Patent Grant
11813463
The present disclosure generally relates to implantable medical devices, and more particularly, to systems that use a leadless cardiac pacemaker for monitoring, pacing and/or defibrillating a patient's heart.
Implantable medical devices are commonly used today to monitor a patient and/or deliver therapy to a patient. For example, and in some instances, pacing devices are used to treat patients suffering from various heart conditions that may result in a reduced ability of the heart to deliver sufficient amounts of blood to a patient's body. Such heart conditions may lead to slow, rapid, irregular, and/or inefficient heart contractions. To help alleviate some of these conditions, various medical devices (e.g., pacemakers, defibrillators, etc.) can be implanted in a patient's body. Such devices may monitor and in some cases provide electrical stimulation (e.g. pacing, defibrillation, etc.) to the heart to help the heart operate in a more normal, efficient and/or safe manner. In some cases, it may be beneficial to detect cardiac events occurring in multiple chambers of the heart. In some cases, this may be used to enhance the effectiveness of the cardiac pacing therapy and/or may allow different types of cardiac pacing therapy to be delivered.
This disclosure generally relates to implantable medical devices, and more particularly, to systems that use a leadless cardiac pacemaker for monitoring, pacing and/or defibrillating a patient's heart. In a first example, a leadless cardiac pacemaker (LCP) may be configured to sense cardiac activity and to deliver pacing therapy to a patient's heart. The LCP may comprise a housing, a first electrode secured relative to the housing and exposed to the environment outside of the housing, a second electrode secured relative to the housing and responsive to the environment outside of the housing, a sensing module (e.g. sensing electronics) disposed within the housing and exposed to the environment outside of the housing, the sensing module configured to detect one or more atrial fiducials that are indicative of an atrial contraction, and a control module (e.g. control electronics) operatively coupled to the first electrode, the second electrode, and the sensing module. The control module may be configured to track the one or more atrial fiducials over a plurality of cardiac cycles and deliver a plurality of different ventricular pacing therapies to the patient's heart via the first electrode and the second electrode, wherein the control module selects which ventricular pacing therapy to deliver based, at least in part, on one or more of the tracked atrial fiducials. patient's heart. The LCP may comprise a housing, a first electrode secured relative to the
Alternatively or additionally to any of the examples above, in another example, the plurality of different ventricular pacing therapies may comprise two or more of VDD, VDDR, VVI, VVIR, VOO and VOOR.
Alternatively or additionally to any of the examples above, in another example, the plurality of different ventricular pacing therapies may comprise a first ventricular pacing therapy having a first pacing rate and a second ventricular pacing therapy having a second pacing rate different from the first pacing rate.
Alternatively or additionally to any of the examples above, in another example, the control module may be configured to dynamically select which ventricular pacing therapy to deliver based, at least in part, on one or more of the tracked atrial fiducials.
Alternatively or additionally to any of the examples above, in another example, the sensing module may be further configured to detect one or more ventricle fiducials that are indicative of a ventricle contraction, and the control module is configured to track the one or more ventricle fiducials over a plurality of cardiac cycles.
Alternatively or additionally to any of the examples above, in another example, the control module may be configured to select which ventricular pacing therapy to deliver based, at least in part, on one or more of the tracked atrial fiducials and one or more of the tracked ventricle fiducials.
Alternatively or additionally to any of the examples above, in another example, the control module may be configured to change from a first ventricular pacing therapy to a second ventricular pacing therapy when a predetermined one of the tracked atrial fiducials comes too close in time to a predetermined one of the tracked ventricle fiducials.
Alternatively or additionally to any of the examples above, in another example, the one or more atrial fiducials may comprise one or more of an electrical p-wave, a pressure a-wave, an acoustic S1 sound, an acoustic S2 sound, an acoustic S3 sound, an acoustic S4 sound, an indication of ventricular volume, an indication of ventricular wall thickness, an indication of cardiac tissue vibration, an indication of mitral valve position, and an indication of tricuspid valve position.
Alternatively or additionally to any of the examples above, in another example, the sensing module may be configured to detect two or more atrial fiducials that are indicative of an atrial contraction, and wherein the control module is configured to select which ventricular pacing therapy to deliver based, at least in part, on a selected one of the tracked atrial fiducials.
Alternatively or additionally to any of the examples above, in another example, the sensing module may be configured to detect two or more atrial fiducials that are indicative of an atrial contraction, and wherein the control module is configured to select which ventricular pacing therapy to deliver based, at least in part, on two or more of the tracked atrial fiducials.
Alternatively or additionally to any of the examples above, in another example, the control module may continuously track the one or more atrial fiducials over a plurality of cardiac cycles.
Alternatively or additionally to any of the examples above, in another example, the control module may intermittently track the one or more atrial fiducials over a plurality of cardiac cycles.
Alternatively or additionally to any of the examples above, in another example, the control module may be configured to switch from delivering a first ventricular pacing therapy to a delivering second ventricular pacing therapy when the control module can no longer track one or more of the atrial fiducials.
Alternatively or additionally to any of the examples above, in another example, the control module may enter a search mode to attempt to re-acquire the one or more of the atrial fiducials that can no longer be tracked.
Alternatively or additionally to any of the examples above, in another example, the sensing module may comprise one or more of a pressure measurement module and an acoustic measurement module.
In another example, a leadless cardiac pacemaker (LCP) may be configured to sense cardiac activity and to deliver pacing therapy to a patient's heart. The LCP may comprise a housing, a first electrode secured relative to the housing and exposed to the environment outside of the housing, a second electrode secured relative to the housing and exposed to the environment outside of the housing, a sensing module disposed within the housing and responsive to the environment outside of the housing, the sensing module including one or more of a pressure measurement module and an acoustic measurement module, the sensing module configured to detect one or more atrial fiducials that are indicative of an atrial contraction and one or more ventricle fiducials that are indicative of a ventricle contraction, and a control module operatively coupled to the first electrode, the second electrode, and the sensing module. The control module may be configured to track the one or more atrial fiducials and one or more ventricle fiducials over a plurality of cardiac cycles and deliver a plurality of different ventricular pacing therapies to the patient's heart via the first electrode and the second electrode, wherein the control module transitions from delivery of a first one of the different ventricular pacing therapies to a second one of the different ventricular pacing therapies based, at least in part, on one or more of the tracked atrial fiducials. The plurality of different ventricular pacing therapies may comprise two or more of VDD, VDDR, VVI, VVIR, VOO and VOOR.
Alternatively or additionally to any of the examples above, in another example, the control module may transition from delivery of a first one of the different ventricular pacing therapies to a second one of the different ventricular pacing therapies based, at least in part, on one or more of the tracked atrial fiducials and one or more of the tracked ventricle fiducials.
Alternatively or additionally to any of the examples above, in another example, the control module may be configured to switch from delivering a first ventricular pacing therapy to a delivering second ventricular pacing therapy when the control module can no longer track one or more of the atrial fiducials.
Alternatively or additionally to any of the examples above, in another example, the plurality of different ventricular pacing therapies may comprise a ventricular pacing therapy having a first pacing rate and a ventricular pacing therapy having a second pacing rate different from the first pacing rate.
In another example, a leadless cardiac pacemaker (LCP) may be configured to sense cardiac activity and to deliver pacing therapy to a patient's heart. The LCP may comprise a housing, a first electrode secured relative to the housing and exposed to the environment outside of the housing, a second electrode secured relative to the housing and exposed to the environment outside of the housing, a sensing module for sensing a hemodynamic state of the patient, and a control module operatively coupled to the first electrode, the second electrode, and the sensing module. The control module may be configured to deliver a plurality of different ventricular pacing therapies to the patient's heart via the first electrode and the second electrode, wherein the control module dynamically selects which ventricular pacing therapy to deliver based, at least in part, on the sensed hemodynamic state of the patient. The plurality of different ventricular pacing therapies may comprise two or more of VDD, VDDR, VVI, VVIR, VOO and VOOR.
Alternatively or additionally to any of the examples above, in another example, the sensing module comprises one or more of a pressure measurement module and an acoustic measurement module.
The above summary is not intended to describe each embodiment or every implementation of the present disclosure. Advantages and attainments, together with a more complete understanding of the disclosure, will become apparent and appreciated by referring to the following description and claims taken in conjunction with the accompanying drawings.
The disclosure may be more completely understood in consideration of the following description of various illustrative embodiments in connection with the accompanying drawings, in which:
While the disclosure is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit aspects of the disclosure to the particular illustrative embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure.
The following description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The description and the drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the disclosure. While the present disclosure is applicable to any suitable implantable medical device (IMD), the description below uses pacemakers and more particularly leadless cardiac pacemakers (LCP) as particular examples.
All numbers are herein assumed to be modified by the term “about”, unless the content clearly dictates otherwise. The recitation of numerical ranges by endpoints includes all numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).
As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include the plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.
It is noted that references in the specification to “an embodiment”, “some embodiments”, “other embodiments”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is contemplated that the feature, structure, or characteristic may be applied to other embodiments whether or not explicitly described unless clearly stated to the contrary.
A normal, healthy heart induces contraction by conducting intrinsically generated electrical signals throughout the heart. These intrinsic signals cause the muscle cells or tissue of the heart to contract in a coordinated manner. These contractions force blood out of and into the heart, providing circulation of the blood throughout the rest of the body. Many patients suffer from cardiac conditions that affect the efficient operation of their hearts. For example, some hearts develop diseased tissue that no longer generate or efficiently conduct intrinsic electrical signals. In some examples, diseased cardiac tissue may conduct electrical signals at differing rates, thereby causing an unsynchronized and inefficient contraction of the heart. In other examples, a heart may generate intrinsic signals at such a low rate that the heart rate becomes dangerously low. In still other examples, a heart may generate electrical signals at an unusually high rate, even resulting in cardiac fibrillation. In some cases such an abnormality can develop into a fibrillation state, where the contraction of the patient's heart chambers are almost completely de-synchronized and the heart pumps very little to no blood. Implantable medical devices, which may be configured to determine occurrences of such cardiac abnormalities or arrhythmias and deliver one or more types of electrical stimulation therapy to patient's hearts, may help to terminate or alleviate these and other cardiac conditions.
It is contemplated that atrial events or artifacts indicative of an atrial event may be used by a device implanted in the right (or left) ventricle to time a pacing pulse for the ventricle in support of treating bradycardia events. In some cases, the timing of the ventricle pacing pulse may be adjusted to maximize the amount of blood entering the right ventricle through passive filling. In some instances, this may include adjusting an AV delay relative to an atrial fiducial (e.g., atrial kick). In some cases, a measured pressure change (or other atrial fiducial) over time may be used to support management of a CRT cardiac therapy (e.g. if placed in the left ventricle), patient health status monitoring and/or any other suitable goal. It is contemplated that measuring events in one of or both of the ventricle and atrium using a single leadless cardiac pacemaker may replicate a dual chamber system using only a single device. For example, such a system may enable a device to be positioned in a ventricle and capable of sensing intrinsic ventricular and atrial events and pacing the ventricle when appropriate (e.g., a VDD pacemaker).
The communication module 102 may be configured to communicate with remote devices such as sensors, other devices, and/or the like, that are located externally and/or internally to the patient's body. The other devices may be device primarily functioning as a medical device (e.g. a LCP programmer, an implanted sensor) or a device primarily functioning as a non-medical device (e.g. a personal computer, tablet computer, smart phone, laptop computer or the like). Irrespective of the location or primary function, the remote devices (i.e., external to the LCP 100 but not necessarily external to the patient's body) may communicate with the LCP 100 via the communication module 102 to accomplish one or more desired functions. For example, the LCP 100 may communicate information, such as sensed signals, data, instructions, messages, etc., to a remote medical device through the communication module 102. The remote medical device may then use the communicated signals, data, instructions and/or messages to perform various functions, such as determining occurrences of arrhythmias, delivering electrical stimulation therapy, storing received data, analyzing received data, transmitting the received data to an external programmer or server or the like for review by a physician, and/or performing any other suitable function. The LCP 100 may additionally receive information such as signals, data, instructions and/or messages from the remote medical device through the communication module 102, and the LCP 100 may use the received signals, data, instructions and/or messages to perform various functions, such as determining occurrences of arrhythmias, delivering electrical stimulation therapy, storing received data, analyzing received data, and/or performing any other suitable function. The communication module 102 may be configured to use one or more methods for communicating with remote devices. For example, the communication module 102 may communicate via radiofrequency (RF) signals, inductive coupling, optical signals, acoustic signals, conducted communication signals, and/or any other signals suitable for communication.
In the example shown in
In some examples, the LCP 100 may not include a pulse generator 104 or may turn off the pulse generator 104. When so provided, the LCP 100 may be a diagnostic only device. In such examples, the LCP 100 may not deliver electrical stimulation therapy to a patient. Rather, the LCP 100 may collect data about cardiac electrical activity and/or other physiological parameters of the patient and communicate such data and/or determinations to one or more other medical devices via the communication module 102.
In some examples, the LCP 100 may include an electrical sensing module 106, and in some cases, a mechanical sensing module 108. The electrical sensing module 106 may be configured to sense the cardiac electrical activity of the heart. For example, the electrical sensing module 106 may be connected to the electrodes 114/114′, and the electrical sensing module 106 may be configured to receive cardiac electrical signals conducted through the electrodes 114/114′. The cardiac electrical signals may represent local information from the chamber (e.g. near field) in which the LCP 100 is implanted. For instance, if the LCP 100 is implanted within a ventricle of the heart, cardiac electrical signals sensed by the LCP 100 through the electrodes 114/114′ may represent ventricular cardiac electrical signals, and possibly some weaker atrial electrical signals. The electrical sensing module 106 may be configured to detect voltage, current and/or impedance. An electrogram sensing module may be provided as a part of the electrical sensing module.
The mechanical sensing module 108 may include one or more sensors, such as an accelerometer, a gyroscope, a microphone, a hydrophone, a blood pressure sensor, a heart sound sensor, a blood-oxygen sensor, a temperature sensor, a flow sensor, a strain sensor, and/or any other suitable sensors that are configured to measure one or more mechanical and/or chemical parameters of the patient. In some cases, the mechanical sensing module 108 may include two or more of a pressure measurement module, an acoustic measurement module, an acceleration measurement module.
Both the electrical sensing module 106 and the mechanical sensing module 108 may be connected to a processing module 110, which may provide signals representative of the sensed mechanical parameters. Although described with respect to
The electrodes 114/114′ can be secured relative to the housing 120 but exposed to the tissue and/or blood surrounding the LCP 100. In some cases, the electrodes 114 may be generally disposed on or near either end of the LCP 100 and may be in electrical communication with one or more of the modules 102, 104, 106, 108, and 110. The electrodes 114/114′ may be supported by the housing 120, although in some examples, the electrodes 114/114′ may be secured relative to the housing 120 through short connecting wires (e.g. tail) such that one or more of the electrodes 114/114′ may be spaced from the housing 120. In examples where the LCP 100 includes one or more electrodes 114′, the electrodes 114′ may in some cases be disposed on the sides of the housing 120 of the LCP 100, which may increase the number of electrodes by which the LCP 100 may sense cardiac electrical activity, deliver electrical stimulation and/or communicate with an external medical device. The electrodes 114/114′ can be made up of one or more biocompatible conductive materials such as various metals or alloys that are known to be safe for implantation within a human body. In some instances, the electrodes 114/114′ connected to LCP 100 may have an insulative portion that electrically isolates the electrodes 114/114′ from adjacent electrodes, the housing 120, and/or other parts of the LCP 100.
The processing module 110 can be configured to control the operation of the LCP 100. For example, the processing module 110 may be configured to receive electrical signals from the electrical sensing module 106 and/or the mechanical sensing module 108. Based on the received signals, the processing module 110 may determine, for example, a need for pacing therapy such as bradycardia therapy, cardiac resynchronization therapy (CRT), anti-tachycardia pacing (ATP) therapy, defibrillation therapy, and/or the like. The processing module 110 may control the pulse generator module 104 to generate electrical stimulation in accordance with one or more pacing therapies. The processing module 110 may further receive information from the communication module 102. In some examples, the processing module 110 may use such received information to help determine the need for pacing therapy and/or what type of pacing therapy. The processing module 110 may additionally control the communication module 102 to send/receive information to/from other devices.
In some examples, the processing module 110 may include a pre-programmed chip, such as a very-large-scale integration (VLSI) chip and/or an application specific integrated circuit (ASIC). In such embodiments, the chip may be pre-programmed with control logic in order to control the operation of the LCP 100. By using a pre-programmed chip, the processing module 110 may use less power than other programmable circuits (e.g., general purpose programmable microprocessors) while still being able to maintain basic functionality, thereby potentially increasing the battery life of the LCP 100. In other examples, the processing module 110 may include a programmable microprocessor. Such a programmable microprocessor may allow a user to modify the control logic of the LCP 100 even after implantation, thereby allowing for greater flexibility of the LCP 100 than when using a pre-programmed ASIC. In some examples, the processing module 110 may further include a memory, and the processing module 110 may store information on and read information from the memory. In other examples, the LCP 100 may include a separate memory (not shown) that is in communication with the processing module 110, such that the processing module 110 may read and write information to and from the separate memory.
The battery 112 may provide power to the LCP 100 for its operations. In some examples, the battery 112 may be a non-rechargeable lithium-based battery. In other examples, a non-rechargeable battery may be made from other suitable materials, as desired. Because the LCP 100 is an implantable device, access to the LCP 100 may be limited after implantation. Accordingly, it is desirable to have sufficient battery capacity to deliver therapy over a period of treatment such as days, weeks, months, years or even decades. In some instances, the battery 112 may a rechargeable battery, which may help increase the useable lifespan of the LCP 100. In still other examples, the battery 112 may be some other type of power source, as desired.
To implant the LCP 100 inside a patient's body, an operator (e.g., a physician, clinician, etc.), may fix the LCP 100 to the cardiac tissue of the patient's heart. To facilitate fixation, the LCP 100 may include one or more anchors 116. The anchor 116 may include any one of a number of fixation or anchoring mechanisms. For example, the anchor 116 may include one or more pins, staples, threads, screws, helix, tines, and/or the like. In some examples, although not shown, the anchor 116 may include threads on its external surface that may run along at least a partial length of the anchor 116. The threads may provide friction between the cardiac tissue and the anchor to help fix the anchor 116 within the cardiac tissue. In other examples, the anchor 116 may include other structures such as barbs, spikes, or the like to facilitate engagement with the surrounding cardiac tissue.
While it is contemplated that the MD 200 may be another leadless device such as shown in
The mechanical sensing module 208, as with the mechanical sensing module 108, may contain or be electrically connected to one or more sensors, such as microphones, hydrophones, accelerometers, gyroscopes, blood pressure sensors, heart sound sensors, blood-oxygen sensors, acoustic sensors, ultrasonic sensors, strain sensors, and/or other sensors which are configured to measure one or more mechanical/chemical parameters of the heart and/or patient. In some examples, one or more of the sensors may be located on the leads 212, but this is not required. In some examples, one or more of the sensors may be located in the housing 220.
While not required, in some examples, the MD 200 may be an implantable medical device. In such examples, the housing 220 of the MD 200 may be implanted in, for example, a transthoracic region of the patient. The housing 220 may generally include any of a number of known materials that are safe for implantation in a human body and may, when implanted, hermetically seal the various components of the MD 200 from fluids and tissues of the patient's body.
In some cases, the MD 200 may be an implantable cardiac pacemaker (ICP). In this example, the MD 200 may have one or more leads, for example leads 212, which are implanted on or within the patient's heart. The one or more leads 212 may include one or more electrodes 214 that are in contact with cardiac tissue and/or blood of the patient's heart. The MD 200 may be configured to sense intrinsically generated cardiac electrical signals and determine, for example, one or more cardiac arrhythmias based on analysis of the sensed signals. The MD 200 may be configured to deliver CRT, ATP therapy, bradycardia therapy, and/or other therapy types via the leads 212 implanted within the heart or in concert with the LCP by commanding the LCP to pace. In some examples, the MD 200 may additionally be configured to provide defibrillation therapy.
In some instances, the MD 200 may be an implantable cardioverter-defibrillator (ICD). In such examples, the MD 200 may include one or more leads implanted within a patient's heart. The MD 200 may also be configured to sense cardiac electrical signals, determine occurrences of tachyarrhythmias based on the sensed signals, and may be configured to deliver defibrillation therapy in response to determining an occurrence of a tachyarrhythmia. In some instances, the MD 200 may be a subcutaneous implantable cardioverter-defibrillator (S-ICD). In examples where the MD 200 is an S-ICD, one of the leads 212 may be a subcutaneously or substernally implanted lead that is spaced from the heart. In at least some examples where the MD 200 is an S-ICD, the MD 200 may include only a single lead which is implanted subcutaneously or substernally, but this is not required. In some cases, the S-ICD lead may extend subcutaneously from the S-ICD can, around the sternum and may terminate adjacent the interior surface of the sternum and spaced from the heart.
In some examples, the MD 200 may not be an implantable medical device. Rather, the MD 200 may be a device external to the patient's body, and may include skin-electrodes that are placed on a patient's body. In such examples, the MD 200 may be able to sense surface electrical signals (e.g., cardiac electrical signals that are generated by the heart or electrical signals generated by a device implanted within a patient's body and conducted through the body to the skin). In such examples, the MD 200 may be configured to deliver various types of electrical stimulation therapy, including, for example, defibrillation therapy. The MD 200 may be further configured to deliver electrical stimulation via the LCP by commanding the LCP to deliver the therapy.
It is contemplated that one or more LCPs 100 and/or one or more MDs 200 may be used in combination as an example medical device system. The various devices 100, 200 may communicate through various communication pathways including using RF signals, inductive coupling, conductive coupling optical signals, acoustic signals, or any other signals suitable for communication. The system may further include and be in communication with a display. The display may be a personal computer, tablet computer, smart phone, laptop computer, or other display as desired. In some instances, the display may include input means for receiving an input from a user. For example, the display may also include a keyboard, mouse, actuatable (e.g., pushable) buttons, or a touchscreen display. These are just examples. Some illustrative medical device systems are described in commonly assigned Patent Application No. 62/547,458, entitled IMPLANTABLE MEDICAL DEVICE WITH PRESSURE SENSOR and filed on Aug. 18, 2017, which is hereby incorporated by reference.
In some cases, the LCP 100 may be in the left ventricle, right atrium or left atrium of the heart, as desired. In some cases, more than one LCP 100 may be implanted. For example, one LCP may be implanted in the right ventricle and another may be implanted in the right atrium. In another example, one LCP may be implanted in the right ventricle and another may be implanted in the left ventricle. In yet another example, one LCP may be implanted in each of the chambers of the heart. Further, the LCP 100 may be used without the second MD 200.
The medical device system 250 may also include an external support device, such as external support device 260. The external support device 260 can be used to perform functions such as device identification, device programming and/or transfer of real-time and/or stored data between devices using one or more of the communication techniques described herein. As one example, communication between the external support device 260 and the MD 200 is performed via a wireless mode (e.g. RF, Bluetooth, inductive communication, etc.), and communication between the MD 200 and the LCP 100 is performed via a conducted mode (e.g. conducted communication). In some examples, communication between the LCP 100 and the external support device 260 is accomplished by sending communication information through the MD 200. However, in other examples, communication between the LCP 100 and the external support device 260 may be direct. In some embodiments, the external support device 260 may be provided with or be in communication with a display 262. The display 262 may be a personal computer, tablet computer, smart phone, laptop computer, or other display as desired. In some instances, the display 262 may include input means for receiving an input from a user. For example, the display 262 may also include a keyboard, mouse, actuatable buttons, or be a touchscreen display. These are just examples.
With reference to
The electrical signal 300 typically instructs a portion of the heart to contract, which then results in a corresponding mechanical contraction. There is a correspondence between a characteristic in the electrical signal (e.g. ECG 300) and a corresponding mechanical response. The mechanical response is typically delayed because it takes some time for the heart to respond to the electrical signal.
It will be appreciated that heart sounds may be considered as one example of mechanical indications of the heart beating. Other illustrative mechanical indications may include, for example, endocardial acceleration or movement of a heart wall detected by an accelerometer in the LCP, acceleration or movement of a heart wall detected by an accelerometer in the SICD, a pressure, pressure change, or pressure change rate in a chamber of the heart detected by a pressure sensor of the LCP, acoustic signals caused by heart movements detected by an acoustic sensor (e.g. accelerometer, microphone, etc.), twisting of the heart detected by a gyroscope in the LCP and/or any other suitable indication of a heart chamber beating.
In some cases, there may be a first heart sound denoted S1 that is produced by vibrations generated by closure of the mitral and tricuspid valves during a ventricular contraction, a second heart sound denoted S2 that is produced by closure of the aortic and pulmonary valves, a third heart sound denoted S3 that is an early diastolic sound caused by the rapid entry of blood from the right atrium into the right ventricle and from the left atrium into the left ventricle, and a fourth heart sound denoted S4 that is a late diastolic sound corresponding to late ventricular filling during an active atrial contraction. These are mechanical responses that can be detected using various sensors (e.g. microphone, hydrophone, accelerometer, etc.).
Because the heart sounds are a result of cardiac muscle contracting or relaxing in response to an electrical signal, it will be appreciated that there is a delay between the electrical signal, indicated by the ECG 300, and the corresponding mechanical indication, indicated in the example shown by the heart sounds trace 302. For example, the P-wave of the ECG 300 is an electrical signal triggering an atrial contraction. The S4 heart sound is the mechanical signal caused by the atrial contraction. In some cases, it may be possible to use this relationship between the P-wave and the S4 heart sound. For example, if one of these signals can be detected, their expected timing relationship can be used as a mechanism to search for the other. For example, if the P-wave can be detected, a window following the P-wave can be defined and searched in order to help find and/or isolate the corresponding S4 heart sound. In some cases, detection of both signals may be an indication of an increased confidence level in a detected atrial contraction. In some cases, detection of either signal may be sufficient to identify an atrial contraction. The identification of an atrial contraction may be used to identify an atrial contraction timing fiducial (e.g. a timing marker of the atrial contraction).
With traditional systems having transvenous leads, the intracardiac electrodes are placed to detect the atrial depolarization while also delivering pacing therapy to one or both ventricles. As a result, the circuitry of a single device would receive, directly, information for the P-wave allowing delivery at a timed interval of a pacing pulse to properly coordinate the ventricular pace with the atrial contraction and improve pumping efficiency. However, with a system only having an LCP implanted within a ventricle, it may be difficult to detect the relatively small P-wave from within the ventricle, and as such, it is contemplated that the LCP may be configured to detect atrial activity without relying on the P-wave (e.g. using S4). The detected atrial activity may be used to identify an atrial timing fiducial that can be used as a basis for timing a pacing pulse in the ventricle (e.g. after an AV delay).
In some examples, a time window for atrial artifact detection is defined during which the LCP 100 may specifically look for atrial artifacts (such as, but not limited to, atrial contraction) to determine an atrial timing fiducial. Such windows may be defined by analysis of the cardiac signals obtained from a patient using, for example, a detected ventricular event such as the R-wave/QRS complex or the T-wave of a previous heart beat as the starting point for timing delays 304, 306, as shown in
In some cases, the relationship of certain electrical signals and/or mechanical indications may be used to predict the timing of other electrical signals and/or mechanical indications within the same heartbeat. Alternatively, or in addition, the timing of certain electrical signals and/or mechanical indications corresponding to a particular heartbeat may be used to predict the timing of other electrical signals and/or mechanical indications within a subsequent heartbeat.
It will be appreciated that as the heart undergoes a cardiac cycle, the blood pressures and blood volumes within the heart vary over time.
Contractions of the atria are initiated near the end of ventricular diastole. The active atrial contraction pushes or forces additional volumes of blood into the ventricles (often referred to as “atrial kick”) in addition to the volumes associated with passive filling. In some cases, the atrial kick contributes in the range of about 20% of the volume of blood toward ventricular preload. At normal heart rates, the atrial contractions are considered highly desirable for adequate ventricular filling. However, as heart rates increase, atrial filling becomes increasingly important for ventricular filling because the time interval between contractions for active filling becomes progressively shorter. Cardiac pressure curves for the pulmonary artery, the right atrium, and the right ventricle, and the cardiac volume curve for the right ventricle, may be similar to those illustrated in
The heart sound signals shown in
In some cases, sensing atrial events or artifacts indicative of an atrial event may allow a device, such as LCP 100 implanted in the ventricle, to detect an atrial contraction, resulting in, for example, an atrial kick. In some cases, signals that provide an indication of an atrial contraction may include one or more of an S3 heart sound signal, an S4 heart sound signal, an A-wave signal (pressure wave) and a P-wave signal. In some cases, signals that can provide an indication of a ventricular contraction may include one or more of an R-wave, a ventricle pressure signal, a ventricle change in pressure signal (dP/dt), a ventricle wall acceleration signal, a ventricle twist signal, a blood flow rate signal, and a ventricle volume signal. These are just some examples.
Some other events or artifacts detected may include, but are not limited to, S1 heart sounds, S2 heart sounds, ventricular volume, ventricular wall dimension, cardiac tissue and/or blood vibration, atrium to ventricle blood movement, ventricular wall and/or atrioventricular (AV) valve position, akinetic pressure, ventricular twist, and any other event or artifact suitable for identifying an atrial event, and/or combinations thereof.
It is contemplated that a number of different sensor modalities may be used to help detect atrial events or artifacts indicative of an atrial event from the ventricle.
In
As shown in
As shown in
As blood enters the ventricle as a result of an atrial contraction, the ventricle may stretch. The stretching of the ventricle may be measure with a strain sensor. A strain sensor may require two or more points of fixation. Acceleration may be used to measure contractility of the heart H, as well as sounds. In some cases, cardiac output can be determined when acceleration measurements are combined with ventricle pressure, cardiac volume and/or other sensed parameters.
It should be understood that the table 320 shown in
The atrial event and/or artifacts indicative of an atrial event may occur during either or both passive ventricular filling or active ventricular filling.
In some instances, ultrasound may use a combined ultrasound source and sensor, although this is not required. The source and sensor may be separately provided, as desired. It is contemplated that ultrasound imaging may be used in a device implanted in the ventricle to see the atrial wall (e.g., through the tricuspid valve), tricuspid closing, and/or a flow increase due to an atrial contraction to help identify an A-wave. In some cases, ultrasound sensor may detect an atrial arrhythmia (e.g. atrial flutter or atrial fibrillation). During normal sinus rhythm (NSR) atrial blood flow into the ventricle is comprised of two sequential components, an E (early) wave followed by an A (atrial) wave. During atrial arrhythmias the E wave is largely unchanged from that in NSR, however the A wave is either missing (atrial fibrillation) or smaller and much faster (atrial flutter). During a detected atrial arrhythmia an LCP with an ultrasound sensor may modify its behavior (e.g. revert from VVD mode to VVI mode).
It should be noted that while the heart sounds are indicated as capable of being identified with an accelerometer, the accelerometer actually measures or detects mechanical vibration associated with the heart sound and not the pressure of the sound waves. In some cases, the measured artifact may not occur distinctly within one cardiac phase or another. For example, ventricular twist may be used to identify the end of active ventricular filling (e.g., ejection). Further, the S1 heart sound may occur at the end of active ventricular filling, while the S2 heart sound may occur shortly before the beginning of passive ventricular filling. These are just some examples.
In some cases, the LCP 100 may be configured to determine an atrial contraction timing fiducial based at least in part upon a sensed indication of an atrial contraction in a first heartbeat and/or a sensed indication of a ventricular contraction in the first heartbeat and/or one or more immediately preceding heartbeat(s). In some cases, the processing module 110 of the LCP 100 may be configured to generate and deliver a ventricle pacing pulse using the determined atrial contraction timing fiducial (e.g. after an A-V delay).
As described above, atrial events or artifacts indicative of an atrial event may be used by an LCP in the ventricle (e.g. right ventricle) to time a pacing pulse for the ventricle in support of treating bradycardia events. In some cases, the timing of the ventricle pacing pulse may be adjusted to improve the amount of blood entering the right ventricle through active filling. In some instances, this may include adjusting an AV delay relative to an atrial fiducial (e.g., atrial kick). In some cases, a measured pressure change (or other atrial fiducial) over time may be used to support management of a CRT cardiac therapy (if placed in the left ventricle), patient health status monitoring and/or any other suitable goal. It is contemplated that detecting events in one of or both of the ventricle and atrium using a single LCP implanted in the ventricle may replicate a dual chamber system with only a single device. That is, a single device positioned in the ventricle may listening to both the ventricle and the atrium and pacing accordingly (e.g., a VDD device).
It is contemplated that the housing 402 may take a variety of different shapes. For example, in some cases, the housing 402 may have a generally cylindrical shape. In other cases, the housing 402 may have a half-dome shape. In yet other embodiments, the housing 402 may be a rectangular prism. It is contemplated that the housing may take any cross sectional shape desired, including but not limited to annular, polygonal, oblong, square, etc.
In some cases, the LCP 400 may include a pulse generator (e.g., electrical circuitry) and a power source (e.g., a battery) within the housing 402 to provide electrical signals to the electrodes 410, 412 to control the pacing/sensing electrodes 410, 412. While not explicitly shown, the LCP 400 may also include a communications module, an electrical sensing module, a mechanical sensing module, and/or a processing module, and the associated circuitry, similar in form and function to the modules 102, 106, 108, 110 described above. The various modules and electrical circuitry may be disposed within the housing 402. Electrical communication between the pulse generator and the electrodes 410, 412 may provide electrical stimulation to heart tissue and/or sense a physiological condition.
In the example shown, the LCP 400 includes a fixation mechanism 414 proximate the distal end 406 of the housing 402. The fixation mechanism 414 is configured to attach the LCP 400 to a wall of the heart H, or otherwise anchor the LCP 400 to the anatomy of the patient. As shown in
The LCP 400 may further include a docking member 420 proximate the proximal end 404 of the housing 402. The docking member 420 may be configured to facilitate delivery and/or retrieval of the LCP 400. For example, the docking member 420 may extend from the proximal end 404 of the housing 402 along a longitudinal axis of the housing 402. The docking member 420 may include a head portion 422 and a neck portion 424 extending between the housing 402 and the head portion 422. The head portion 422 may be an enlarged portion relative to the neck portion 424. For example, the head portion 422 may have a radial dimension from the longitudinal axis of the LCP 400 that is greater than a radial dimension of the neck portion 424 from the longitudinal axis of the LCP 400. In some cases, the docking member 420 may further include a tether retention structure 426 extending from or recessed within the head portion 422. The tether retention structure may define an opening 428 configured to receive a tether or other anchoring mechanism therethrough. The retention structure may take any shape that provides an enclosed perimeter surrounding the opening such that a tether may be securably and releasably passed (e.g., looped) through the opening 428. In some cases, the retention structure may extend though the head portion 422, along the neck portion 424, and to or into the proximal end 404 of the housing 402. The docking member 420 may be configured to facilitate delivery of the LCP 400 to the intracardiac site and/or retrieval of the LCP 400 from the intracardiac site. While this describes one example docking member 420, it is contemplated that the docking member 420, when provided, can have any suitable configuration.
It is contemplated that the LCP 400 may include one or more sensors 430 coupled to or formed within the housing 402 such that the sensor(s) is exposed to and/or otherwise operationally coupled with (e.g., responsive to) the environment outside the housing 402 to measure or detect various artifacts within the heart. The one or more sensors 430 may be of a same modality or a combination of two or more different sensing modalities, as desired. For example, the one or more sensors 430 may be use voltage, pressure, sound, ultrasound, impedance, strain, acceleration, flow, and/or rotation to detect P-waves, A-waves, S1-S4 heart sounds, ventricular volume, ventricular wall dimensions, cardiac tissue and/or blood vibration, atrium to ventricle blood movement, ventricular wall and/or atrioventricular valve position, akinetic pressure, and/or ventricular twist, such as described with respect to
In some cases, the one or more sensors 430 may be coupled to an exterior surface of the housing 402. In other cases, the one or more sensors 430 may be positioned within the housing 402 with an artifact acting on the housing and/or a port on the housing 402 to affect the sensor 430. In one illustrative example, if the LCP 400 is placed in the right ventricle, the sensor(s) 430 may be a pressure sensor configured to measure a pressure within the right ventricle. If the LCP 400 is placed in another portion of the heart (such as one of the atriums or the left ventricle), the pressures sensor(s) may measure the pressure within that portion of the heart. In some cases, the sensor(s) 430 may be sensitive enough to detect an artifact in a heart chamber different from the chamber in which the LCP 400 is positioned. For example, in some instances a sensor 430 may detect a pressure change caused by an atrial contraction (e.g., atrial kick) when the LCP 400 is placed in the right ventricle. Some illustrative sensor configurations will be described in more detail herein.
While it is desirable to identify an atrial contraction often associated with the A-wave, the A-wave can be difficult to detect as it may be very small in magnitude and detection of it may come and go. It is contemplated that a combination of sensor modalities and/or measured atrial artifacts may be used to identify an atrial timing fiducial. For example, it is contemplated that any of the sensor modalities identified with respect to
In some cases, the circuitry and/or processing module of the LCP 400 may also be configured determine an atrial contraction timing fiducial based at least in part upon two or more of a signal received from the electrical sensing module, mechanical sensing module, and/or communication module. In some cases, the electrical cardiac signal received via the electrode arrangement 410, 412 may include at least a portion of an electrocardiogram (ECG). In some cases, the electrical cardiac signal received via electrode arrangement 410, 412 may include a P-wave. In some instances, the electrical cardiac signal received via the electrode arrangement 410, 412 may include a QRS complex, from which a QRS width can be determined. In some cases, the electrical cardiac signal received via electrode arrangement 410, 412 may include two consecutive R waves, from which an R-wave to R-wave interval can be determined. In some cases, the electrical cardiac signal may include a conducted or other communicated electrical signal from another device (e.g. SICD device) that includes an indication of an atrial or other contraction of the heart H. In some cases, the processing module and/or circuity may be configured to generate and deliver a ventricle pacing pulse using the atrial contraction timing fiducial.
It is contemplated that the use of sensors to determine an atrial contraction timing fiducial without having to detect the A-wave may allow the LCP 100, 400 to predict or recognize when an A-wave likely occurred, even when the A-wave itself was not detected. The predicted time of the A-wave may then be used as an atrial contraction timing fiducial for pacing the ventricle. The A-wave may be particularly difficult to detect when, for example, the heart is experiencing atrial fibrillation, a patient is in certain postures, the respiration rate is high, the patient activity is high, the heart rate is high, the atria are hypocontractile or akinetic, and/or during periods of high heart rate variability (HRV).
In the cardiac cycle, the ventricles receive blood from the atria first through passive filling and then through active filling. Discussion of passive and active filling will be described with reference to a right side of the heart, however, it should be understood that a similar process is occurring in the left side of the heart. Passive filling of the right ventricle begins when the there is a pressure gradient between the chambers causing the tricuspid valve to open and blood accumulated in the right atrium to flow into the right ventricle. Both the right atrium and the right ventricle continue to fill as blood returns to the heart. The right atrium contracts near the end of ventricular diastole. Atrial depolarization begins at the P-wave of the electrocardiogram. As a result of the P-wave, atrial cells develop tension and shortening causing the atrial pressure to increase (e.g. A-wave). These active contraction forces force additional volumes of blood into the ventricle (often referred to as the “atrial kick”). The active contraction forces begin the active filling phase. At normal heart rates, the atrial contractions are considered desirable for adequate ventricular filling. As heart rate increases, atrial filling becomes increasingly important for ventricular filling because the time interval between contractions for filling becomes progressively shorter. Atrial fibrillation and/or asynchronized atrial-ventricular contractions can result in a minimal contribution to preload via atrial contraction.
As described above, the fourth heart sound (e.g., S4) is typically a gallop sound that results from a forceful atrial contraction during presystole that ejected blood into a ventricle which cannot expand further. The fourth heart sound occurs during the last one-third of diastole about 90 milliseconds before S1. The frequency of S4 may be in the range of about 15 Hertz (Hz) to about 30 Hz, although the frequency may sometimes be outside this range. Due to the low pitch, S4 (and sometimes S3) are usually not audible with a typical stethoscope. It is contemplated that the S4 heart sound may be used to identify the start of active filling of the ventricle. In some cases, the processing module 110 and/or circuitry may be programmed to begin looking for the S4 heart sound just before the S1 heart sound is expected (projected from one or more previous heart beats).
The heart sounds may be time dependent on the heart rate in manner that changes linearly with the heart rate. For example, as the heart rate increases, the time between the heart sounds (e.g. S1 to S1; S4 to S1, etc.) may decrease in a linear and predicable manner. This may allow the S4 heart sound to be used to identify a reliable atrial event and/or as an atrial timing fiducial over a range of heart rates.
As noted above, the S4 heart sound may be identified and/or detected using a variety of different sensors, including but not limited to a higher frequency pressure sensor (e.g. 15 to 30 Hz), a hydrophone, a microphone, and/or an accelerometer. These are just some examples of how the LCP 400 can detect an artifact during active ventricular filling and identify an atrial timing fiducial based on the detected artifact.
While the above example was described with respect to active filling, it is contemplated that an artifact identified during passive filling may also be used to identify an atrial event which may then be used to identify an atrial timing fiducial. For example, the third heart sound (e.g., S3) occurs near the middle of passive filling. Passive filling may generate a very low frequency sound (in the range of 0 to 10 Hz) which may be detected by a DC capable pressure sensor. This may allow the S3 heart sound to be used to identify an atrial event and/or as an atrial timing fiducial over a range of heart rates.
In some instances, the first signal and/or the second signal may be generated via one or more sensors within or on the housing the LCP. As described above, the sensing module of the LCP 400 may sense different events depending on whether attempting to identify active filling or passive filling (see
The circuitry within the LCP 400 may be configured to determine an atrial timing fiducial based at least in part on the first and/or second sensed signals, as indicated at block 506. For example, the circuitry may be configured to determine when the A-wave occurs based on a sensed S4 heart sound and/or other atrial artifact. This is just one example. Those skilled in the art will recognize that any number of artifacts (or combinations thereof) can be used to determine an atrial timing fiducial. The circuitry may be configured to then generate and deliver a ventricular pacing pulse using the determined atrial timing fiducial, as indicated at block 508. The control circuitry may delay delivering a pacing pulse to the ventricle until an appropriate AV delay expires after the determined atrial timing fiducial. Notably, a different AV delay may be used for different atrial timing fiducials (see
While the control timing of the pacing pulse may be triggered by an atrial timing fiducial that is based on arterial artifacts detected during a single heart beat, it is contemplated that the pacing pulse may be triggered by an atrial timing fiducial that is based on arterial and/or other artifacts detected during two or more previous heart beats. In some cases, the LCP may determine an average timing for a particular atrial artifact and/or atrial timing fiducial over multiple heart beats.
The circuitry of the LCP may further be configured to determine intrinsic intervals within the cardiac cycle. This capability may be provided within the control circuitry or provided as a separate interval determination module in the LCP. In some cases, the circuitry may be configured to identify intrinsic intervals including atrial to atrial event or artifact intervals, atrial to ventricle event or artifact intervals, ventricle to atrial event or artifact intervals, and/or ventricle to ventricle event or artifact intervals. This information may be useful in predicting when, for example, an atrial event (e.g. A-wave) is expected to occur. This may be useful in, for example, confirming an atrial event that is sensed by the LCP. This may also be useful in identifying a window of time around which an atrial event is expected, such that the LCP may increase amplification and/or add special filtering and/or signal averaging (e.g. see
In some cases, the sensing module of the LCP may be configured to manipulate the signal prior to identifying an atrial event. For example, the sensing module may include one or more filters for filtering a signal. In some cases, the filter may include a first filter for passing a first frequency band, a second filter for passing a second frequency band, and a third filter for passing a third frequency band. The filter may include more than three frequency bands or fewer than three frequency bands, as desired. In some cases, the filter may be band-pass filter, a low pass filter, a high pass filter, and/or any other suitable filter. In some cases, a band-pass filter may be in the range of 1 to 5 Hz. In other cases, a bandpass filter may be in the range of 15 to 30 Hz. In yet another example, the filter may be a low-pass filter in the range of 0 to 10 Hz. These are just examples; other frequency ranges can be used, as desired. Also, filters may be employed that are not based on frequency, but rather some other signal feature such as amplitude, phase, etc.
In some cases it may be desirable to limit the time frame in which the LCP 400 is looking for an atrial artifact. For example, battery life may be increased when the circuitry is searching for an artifact only during a limited window or period of time that is less than an entire cardiac cycle. The method for determining a time window for searching for an atrial artifact may include first identifying an expected time frame for the atrial event (e.g., atrial contraction) and then defining a search window accordingly. Referring to
A window 560 where an atrial event is expected to occur can then be isolated. For example, an atrial event (e.g., atrial contraction) may be expected to occur within a time window 560 before the next R-wave. Using this time window 560, the LCP may search for the atrial event. In some cases, the LCP may increase amplification and/or add special filtering and/or signal averaging to help identify the atrial event during the time window 560. In some case, the window 560 can be used as a reference point for determining another window in which another signal should be recorded and searched to identify an atrial artifact from which an atrial event can be deduced.
In some cases, the timing window for identifying an atrial contraction may be based on artifacts occurring during passive filling of the ventricle. In some cases the down-stroke of the ventricular pressure (e.g., when the A-V valve opens) may be used to open a timing window for detecting an atrial artifact and/or atrial contraction. An upslope in ventricular pressure may trigger an open sensing window to detect the atrial kick.
In another example, the S2 heart sound may be used to identify the start of passive filling. It is contemplated that a pressure sensor in the LCP may be used to detect the pressure change associated with the atrial kick, or any of the atrial artifacts identified herein can be used either alone or in combination with the atrial kick as the atrial timing fiducial. The LCP 100, 400 can then pace the ventricle based off of the artifact, the atrial kick or a combination thereof. In another example, ventricular impedance may be used to identify volume changes in the ventricle, which may then be used to infer a pressure wave due to the atrial contraction. In another example, one or more atrial artifacts may be used to identify the end of passive filling for hemodynamic optimization. For example, passive filling may by typically completed approximately 500 milliseconds after the S2 heart sound. In yet another example, the timing window may be open between the S3 and S4 heart sounds. In some cases, the control module of the LCP may set a decreasing signal threshold to allow smaller signals to reach the input amplifier after the S3 heart sound in order to increase the signal. In some cases, the control module may be configured to run a continuous integration of the pressure signal as a surrogate for pressure, which may then be used to create a timing window. It is contemplated that changes in ventricular filling and/or pressures over time may be used to pick up respiration signals that may be used to support other features of the LCP 100, 400. These are just some examples of how atrial artifacts can be detected by an LCP within the ventricle, which can then be used to identify an atrial timing fiducial for use in timing delivery of a pacing pulse to the ventricle.
It is contemplated that the control module of the LCP 100, 400 may be configured to search for an atrial artifact and identify a search window in more than one manner. In some cases, pacing can cover up, hide, or otherwise distort atrial artifacts and may make then difficult to identify. It may be desirable to allow the LCP to enter a listening mode in which the control circuitry does not issue pacing commands. The listening mode may be for a predefined window of time during a cardiac cycle that is less than the entire cardiac cycle. This may allow the LCP 400 to identify an atrial event without hiding or covering up the atrial artifact of interest (e.g. the A-wave). In some cases, such as when the patient is not pacing dependent, pacing can be paused for a cardiac cycle or two when no atrial activity is detected in order to determine if pacing is covering the atrial artifact(s) if interest. If the patient is pacing dependent, the pacing rate may be slowed (period extended) to allow for a larger period of time to search for the atrial artifacts without a pacing pulse present. Once the atrial artifact has been identified, the LCP may use the artifact to control the timing of the pacing pulse for a one or more cardiac cycles. In the event that an atrial artifact is not found, the LCP may return to its original pacing rate. In some cases, the LCP may be configured to pause or delay pacing and look for an atrial artifact and/or event on a predetermined time schedule.
It is further contemplated that in the event that the atrial artifact is not found the control module may be configured to deliver a pacing therapy at an altered pacing rate. In an example, the altered pacing rate may be less than the pacing rate delivered while atrial events are detected. In another example, the altered pacing rate may be greater than the pacing rate delivered while atrial events are detected. In a further example, the altered pacing rate may be static (e.g., remain constant) during the time there is a failure to detect atrial events. In yet another example, the altered pacing rate may be dynamic (e.g., change) during the time there is a failure to detect atrial events.
In another example, the control module may be configured to switch to a pacing only mode (in some cases a VOO mode). In this example, the control module may be configured to analyze the inputs received from the various sensor modules to determine if some sensors are providing a clearer signal than others. The control module may be configured to prioritize which sensor module is used to search for an atrial artifact and/or event before re-entering VDD mode. When in VOO mode, it may be desirable to pace off of the P-wave. However if this is not possible, it may be desirable to open a timing window based on other sensors including, but not limited to, pressure sensors and/or accelerometers to identify an atrial contraction. It is contemplated that the control module may be configured to switch between sensing modes and pacing modes as needed.
The control module may be configured to determine a quality threshold for a timing window, which may reflect the quality of the atrial artifact signal identified during the timing window. For example, the control module may be configured to analyze or grade a current A-wave timing window. If the current A-wave timing window does not meet certain quality metrics (e.g. percent of cardiac cycles in which an A-Wave is detected, the signal-to-noise ration of the detected A-wave signal, etc.), the control module may discard the window and use a previous window or calculate a new timing window. In some cases, the control module may prioritize one type of atrial artifact over another based on the quality of the detected signal.
As described above, the LCP 100, 400 may use different atrial and/or ventricle artifacts to determine when to search for an artifact and when to open the timing window. The LCP 100, 400 may include a sensing module that includes at least two of a pressure measurement module, an acoustic measurement module, an acceleration measurement module, and an electrogram measurement module. In some cases, the sensing module may include at least a pressure measurement module and at least one of an acoustic measurement module, an acceleration measurement module, and an electrogram measurement module. In some cases, the control module may use a ventricular event such as the R-wave to identify when to start a search window. In some cases, the control module may use different search windows to identify atrial artifacts from different measurement modules. The control module may identify a window of time during each of one or more cardiac cycles in which an atrial artifact and/or atrial event is expected to occur. The window of time may be less than an entire cardiac cycle. The control module may analyze information gathered by the sensing module (e.g., using at least one of the pressure measurement module, an acoustic measurement module, an acceleration measurement module, and an electrogram measurement module) to identify an atrial event (e.g., atrial kick). The control module may then deliver or command a pacing module to deliver a ventricular pacing pulse via the pacing electrodes of the LCP. The ventricular pacing pulse is delivered at a time that is based at least in part on the timing of the identified atrial event. For example, the pacing pulse may be delivered a predetermined length of time (e.g. A-V delay) after the identified atrial event. It is contemplated that the A-V delay that is used may depend on the particular atrial event that was identified. That is, different atrial events may cause different A-V delays to be applied.
The control module may be further configured to average the signals gathered from the sensing module in a similar manner to that described with respect to
In some cases, the control module may be configured to move the window of time to search for an atrial artifact and/or atrial event. For example, if one of measurement modules of the sensor module is providing a better signal (e.g. better SNR), the control module may base the window around the detected artifact with a clearer signal. As the artifacts can occur at varying time points within the cardiac cycle, the window may be moved accordingly, sometimes cycle-to-cycle. The control module may be configured to select which measurement module to use dynamically or on a case to case basis.
In some cases, the control module may use different quality measurements to determine which measurement module to use. For example, the control module may select the measurement module with a better Signal-to-Noise Ratio (SNR). In another example, a p-wave detecting atrial activation by an electrogram measurement module may have a higher priority than a pressure signal detecting an atrial kick by a pressure measurement module. However, due to the inability of a ventricle only configuration to reliably sense a P-wave, the LCP may not rely solely on the P-wave to identify an atrial artifact and/or event. It may in fact, it may switch to detecting the A-wave when the P-wave is not available, and/or may use the A-wave to confirm the detection of a noisy P-wave. These are just examples.
In some cases, the control module may combine information gathered from more than one measurement module in identifying an atrial artifact and/or atrial event. For example, the control module may use both pressure data and electrocardiogram data in identifying an atrial artifact and/or event. In some cases, when data is used from two or more measurement modules, the data from each measurement module may be weighted differently (e.g., one may count more or be weighted more heavily than another). It is further contemplated that the control module may be configured to lengthen the window (e.g., make it longer) under certain conditions. For example, the window may not be long enough to identify an atrial artifact and/or event or a pacing pulse may be covering up the atrial event. In other cases, the window may be shortened (e.g., when noise is present, the noise may be reduced with a shortened window).
As described herein, the timing intervals for both searching and pacing may be based on pressure and/or heart sound fiducials (as well as other atrial artifacts described herein) as opposed to basing the intervals off solely of an electrocardiogram.
As illustrated in
The E-E (R-wave to subsequent R-wave), A-A (S1 to subsequent S1), and P-P (max pressure to subsequent max pressure) intervals shown at 702 are three ventricular intervals. The E-E (P-wave to subsequent P-wave), A-A (S4 to subsequent S4), and P-P (atrial kick to subsequent atrial kick) intervals shown at 704 are three atrial intervals. These intrinsic same chamber intervals 706 have the same or roughly the same time interval between same sensed artifacts or events regardless of which parameter is used (e.g., R-wave to R-wave, S1 to S1, max pressure to max pressure). In contrast, intervals between chambers 708 vary substantially. As can be seen at 708 in
As described above, a P-wave may not be consistently detected in a device implanted in the ventricle. As such, it may be desirable to time the ventricular pacing pulse (VP) using a pressure artifact (e.g., a-wave or atrial kick) as the atrial timing fiducial along with a corresponding AV interval. In another example, it may be desirable to time the ventricular pacing pulse (VP) using an acoustic artifact (e.g., S4) as the atrial timing fiducial along with a corresponding AV interval. The corresponding AV interval used with an acoustic artifact (e.g., S4) may be different than the AV interval used with a pressure artifact, as seen at 710 in
The sensing module of the LCP 100, 400 may include one or more of a pressure measurement module and an acoustic measurement module. However, other measurement modules may be used as desired, including but not limited to, measurement modules that include suitable sensors for determining the artifacts described with respect to
In some cases, a pressure measurement module may detect or determine at least one of a maximum pressure (atrial or ventricular), a minimum pressure (atrial or ventricular), a mean pressure (atrial or ventricular), a pressure time integral (atrial or ventricular), and/or a pressure time derivative (atrial or ventricular). An acoustic measurement module may detect or determine at least one of an S1 heart sound, an S2 heart sound, an S3 heart sound, and/or an S4 heart sound. An acceleration measurement module, if present, may detect or determine at least of an S1 heart sound, an S2 heart sound, an S3 heart sound, an S4 heart sound, myocardial (e.g., heart wall) movement, patient activity and/or patient posture. These and other artifacts may be used as the basis for an atrial timing fiducial.
In some cases, it may be desirable for the LCP 100, 400 to be configured to operate in a number of different pacing modes. Some illustrative pacing modes may include, but are not limited to VDD, VDDR, VVI, VVIR, VOO, and VOOR. As used herein, the pacing modes use the North American Society of Pacing and Electrophysiology (NASPE) and British Pacing and Electrophysiology Group (BPEG) pacemaker codes as outlined in Table 1 below:
A VDD device is a device pacing in the ventricle, sensing both the atrium and the ventricle, and using triggered and inhibited pacing.
It is contemplated that a right ventricle LCP 100, 400 using remote tracking of atrial activity such as described herein may automatically revert from one pacing mode to another, depending on one or more sensed conditions. The reversionary behavior may be desirable for safe operation and/or for enhancing the effectiveness of the pacing therapy. The control module may be configured to search for and identify conditions that may indicate a reversion is desirable. Some conditions may include, but are not limited to: an atrial artifact (e.g., atrial timing fiducial) occurring too close to the R-wave (or other ventricular fiducial); a hemodynamic response that indicates that the present pacing therapy is worse than another pacing therapy or no pacing therapy, either actual or anticipated (due to one or more of posture, heart rate, respiratory rate, respiratory cycle, patient activity, physiological noise, environmental noise, etc.); continuous or intermittent loss of an atrial tracking artifact or fiducial; actual or anticipated continuous or intermittent loss of an atrial tracking artifact or fiducial due to search algorithms associated with reacquiring an atrial artifact or fiducial; a time period between adjacent atrial artifacts or fiducials being too short (e.g., due to over sensing caused by physiological or environmental noise or atrial tachyarrhythmia); and/or a ventricular interval being too short (e.g., due to over sensing caused by physiological or environmental noise or ventricular tachyarrhythmia). These are just some examples. Other events and conditions may be detected and cause reversionary behavior.
The LCP 100, 400 may experience or be configured to use different types of reversionary behavior based on the current conditions. In a first example, the control module may be configured to change pacing modes. In the event of a loss of an atrial timing fiducial, an atrial rate above a specified threshold, or atrial noise above a threshold, the LCP may be configured to automatically switch between VDD and VVI modes. In the event of ventricular noise being above a threshold, the LCP may be configured to automatically switch between VDD or VVI and VOO modes. In the event of a reduction in the hemodynamic signal, the LCP may be configured to automatically switch between VDD or VVI and OOO modes.
In an example LCP 100, 400 reverts to a VDI mode wherein the device continues to search and/or measure atrial artifacts but does not use any detected atrial artifacts to trigger ventricular pacing. If the LCP determines the atrial fiducial can be reliably determined the LCP reverts back to a mode that allows triggering of ventricular paces from the atrial fiducial (e.g. VDD mode).
In some cases, the control module may be configured to manipulate the tracking algorithm. For example, the control module may switch between continuous tracking and intermittent tracking with tracking estimate and search. In yet another example, the atrial timing fiducial signal may be reverted. In another example, the type of signal and/or portion of signal used to determine the atrial timing fiducial may be changed or switched. In yet another example, the atrial timing fiducial may be changed from a first weighted average of two or more signals to a second different weighted average of the same or different two or more signals. These are just examples.
The control module may be configured to determine the accuracy of the atrial timing fiducial by analyzing the effectiveness of the pacing therapy. In one example, the control module may use the upstroke (e.g., dP/dt or peak pressure) on sequential cardiac cycles to estimate the accuracy of the A-wave detection. If the LCP 100, 400 is pacing at an incorrect time due to an inaccurate atrial timing fiducial, passive filling may be reduced thereby reducing the dP/dt. Similarly, the control module may use an integrator to find the area under the pressure waveform, which may represents the filling volume of the ventricle, or impedance between the electrodes of the LCP may be used as an indication of ventricle volume. Poor filling volume may indicate an inaccurate atrial timing fiducial. In yet another example, the control module may be configured to search for edges using, for example a high-pass pole to create a differentiator to help identify a sub-par atrial timing fiducial. If the atrial timing fiducial is determined to be inaccurate, the LCP may revert to asynchronous pacing (e.g. VOO mode). Alternatively, if the patient's intrinsic heart rate is high enough (e.g. 50 BPM), the LCP may revert to no pacing (e.g. OOO mode).
In addition to a first-order differentiator, higher-order differentiation could further provide better timing fiducials (e.g., more crisp) and other measures such as verification of signal quality. A third order time derivative of position is known as “jerk”, which is the change in acceleration with respect to time.
Those skilled in the art will recognize that the present disclosure may be manifested in a variety of forms other than the specific examples described and contemplated herein. For instance, as described herein, various examples include one or more modules described as performing various functions. However, other examples may include additional modules that split the described functions up over more modules than that described herein. Additionally, other examples may consolidate the described functions into fewer modules. Accordingly, departure in form and detail may be made without departing from the scope and spirit of the present disclosure as described in the appended claims.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/593,662 filed on Dec. 1, 2017, the disclosure of which is incorporated herein by reference.
| Number | Name | Date | Kind |
|---|---|---|---|
| 3835864 | Rasor et al. | Sep 1974 | A |
| 3943936 | Rasor et al. | Mar 1976 | A |
| 4142530 | Wittkampf | Mar 1979 | A |
| 4151513 | Menken et al. | Apr 1979 | A |
| 4157720 | Greatbatch | Jun 1979 | A |
| RE30366 | Rasor et al. | Aug 1980 | E |
| 4243045 | Maas | Jan 1981 | A |
| 4250884 | Hartlaub et al. | Feb 1981 | A |
| 4256115 | Bilitch | Mar 1981 | A |
| 4263919 | Levin | Apr 1981 | A |
| 4310000 | Lindemans | Jan 1982 | A |
| 4312354 | Walters | Jan 1982 | A |
| 4323081 | Wiebusch | Apr 1982 | A |
| 4357946 | Dutcher et al. | Nov 1982 | A |
| 4365639 | Goldreyer | Dec 1982 | A |
| 4440173 | Hudziak et al. | Apr 1984 | A |
| 4476868 | Thompson | Oct 1984 | A |
| 4522208 | Buffet | Jun 1985 | A |
| 4537200 | Widrow | Aug 1985 | A |
| 4556063 | Thompson et al. | Dec 1985 | A |
| 4562841 | Brockway et al. | Jan 1986 | A |
| 4593702 | Kepski et al. | Jun 1986 | A |
| 4593955 | Leiber | Jun 1986 | A |
| 4630611 | King | Dec 1986 | A |
| 4635639 | Hakala et al. | Jan 1987 | A |
| 4674508 | DeCote | Jun 1987 | A |
| 4712554 | Garson | Dec 1987 | A |
| 4729376 | DeCote | Mar 1988 | A |
| 4754753 | King | Jul 1988 | A |
| 4759366 | Callaghan | Jul 1988 | A |
| 4776338 | Lekholm et al. | Oct 1988 | A |
| 4787389 | Tarjan | Nov 1988 | A |
| 4793353 | Borkan | Dec 1988 | A |
| 4819662 | Heil et al. | Apr 1989 | A |
| 4858610 | Callaghan et al. | Aug 1989 | A |
| 4886064 | Strandberg | Dec 1989 | A |
| 4887609 | Cole | Dec 1989 | A |
| 4928688 | Mower | May 1990 | A |
| 4967746 | Vandegriff | Nov 1990 | A |
| 4987897 | Funke | Jan 1991 | A |
| 4989602 | Sholder et al. | Feb 1991 | A |
| 5012806 | De Bellis | May 1991 | A |
| 5036849 | Hauck et al. | Aug 1991 | A |
| 5040534 | Mann et al. | Aug 1991 | A |
| 5058581 | Silvian | Oct 1991 | A |
| 5078134 | Heilman et al. | Jan 1992 | A |
| 5109845 | Yuuchi et al. | May 1992 | A |
| 5113859 | Funke | May 1992 | A |
| 5113869 | Nappholz et al. | May 1992 | A |
| 5117824 | Keimel et al. | Jun 1992 | A |
| 5127401 | Grevious et al. | Jul 1992 | A |
| 5133353 | Hauser | Jul 1992 | A |
| 5144950 | Stoop et al. | Sep 1992 | A |
| 5170784 | Ramon et al. | Dec 1992 | A |
| 5179945 | Van Hofwegen et al. | Jan 1993 | A |
| 5193539 | Schulman et al. | Mar 1993 | A |
| 5193540 | Schulman et al. | Mar 1993 | A |
| 5241961 | Henry | Sep 1993 | A |
| 5243977 | Trabucco et al. | Sep 1993 | A |
| 5259387 | DePinto | Nov 1993 | A |
| 5269326 | Verrier | Dec 1993 | A |
| 5284136 | Hauck et al. | Feb 1994 | A |
| 5300107 | Stokes et al. | Apr 1994 | A |
| 5301677 | Hsung | Apr 1994 | A |
| 5305760 | McKown et al. | Apr 1994 | A |
| 5312439 | Loeb | May 1994 | A |
| 5313953 | Yomtov et al. | May 1994 | A |
| 5314459 | Swanson et al. | May 1994 | A |
| 5318597 | Hauck et al. | Jun 1994 | A |
| 5324316 | Schulman et al. | Jun 1994 | A |
| 5331966 | Bennett et al. | Jul 1994 | A |
| 5334222 | Salo et al. | Aug 1994 | A |
| 5342408 | deCoriolis et al. | Aug 1994 | A |
| 5370667 | Alt | Dec 1994 | A |
| 5372606 | Lang et al. | Dec 1994 | A |
| 5376106 | Stahmann et al. | Dec 1994 | A |
| 5383915 | Adams | Jan 1995 | A |
| 5388578 | Yomtov et al. | Feb 1995 | A |
| 5404877 | Nolan et al. | Apr 1995 | A |
| 5405367 | Schulman et al. | Apr 1995 | A |
| 5411031 | Yomtov | May 1995 | A |
| 5411525 | Swanson et al. | May 1995 | A |
| 5411535 | Fujii et al. | May 1995 | A |
| 5441489 | Utsumi et al. | Aug 1995 | A |
| 5456691 | Snell | Oct 1995 | A |
| 5458622 | Alt | Oct 1995 | A |
| 5466246 | Silvian | Nov 1995 | A |
| 5468254 | Hahn et al. | Nov 1995 | A |
| 5472453 | Alt | Dec 1995 | A |
| 5522866 | Fernald | Jun 1996 | A |
| 5540727 | Tockman et al. | Jul 1996 | A |
| 5545186 | Olson et al. | Aug 1996 | A |
| 5545202 | Dahl et al. | Aug 1996 | A |
| 5571146 | Jones et al. | Nov 1996 | A |
| 5591214 | Lu | Jan 1997 | A |
| 5620466 | Haefner et al. | Apr 1997 | A |
| 5634938 | Swanson et al. | Jun 1997 | A |
| 5649968 | Alt et al. | Jul 1997 | A |
| 5662688 | Haefner et al. | Sep 1997 | A |
| 5674259 | Gray | Oct 1997 | A |
| 5683426 | Greenhut et al. | Nov 1997 | A |
| 5683432 | Goedeke et al. | Nov 1997 | A |
| 5706823 | Wodlinger | Jan 1998 | A |
| 5709215 | Perttu et al. | Jan 1998 | A |
| 5720770 | Nappholz et al. | Feb 1998 | A |
| 5728154 | Crossett et al. | Mar 1998 | A |
| 5741314 | Daly et al. | Apr 1998 | A |
| 5741315 | Lee et al. | Apr 1998 | A |
| 5752976 | Duffin et al. | May 1998 | A |
| 5752977 | Grevious et al. | May 1998 | A |
| 5755736 | Gillberg et al. | May 1998 | A |
| 5759199 | Snell et al. | Jun 1998 | A |
| 5774501 | Halpern et al. | Jun 1998 | A |
| 5792195 | Carlson et al. | Aug 1998 | A |
| 5792202 | Rueter | Aug 1998 | A |
| 5792203 | Schroeppel | Aug 1998 | A |
| 5792205 | Alt et al. | Aug 1998 | A |
| 5792208 | Gray | Aug 1998 | A |
| 5814089 | Stokes et al. | Sep 1998 | A |
| 5827216 | Igo et al. | Oct 1998 | A |
| 5836985 | Rostami et al. | Nov 1998 | A |
| 5836987 | Baumann et al. | Nov 1998 | A |
| 5842977 | Lesho et al. | Dec 1998 | A |
| 5855593 | Olson et al. | Jan 1999 | A |
| 5873894 | Vandegriff et al. | Feb 1999 | A |
| 5891184 | Lee et al. | Apr 1999 | A |
| 5897586 | Molina | Apr 1999 | A |
| 5899876 | Flower | May 1999 | A |
| 5899928 | Sholder et al. | May 1999 | A |
| 5919214 | Ciciarelli et al. | Jul 1999 | A |
| 5935078 | Feierbach | Aug 1999 | A |
| 5941906 | Barreras, Sr. et al. | Aug 1999 | A |
| 5944744 | Paul et al. | Aug 1999 | A |
| 5954757 | Gray | Sep 1999 | A |
| 5978713 | Prutchi et al. | Nov 1999 | A |
| 5991660 | Goyal | Nov 1999 | A |
| 5991661 | Park et al. | Nov 1999 | A |
| 5999848 | Gord et al. | Dec 1999 | A |
| 5999857 | Weijand et al. | Dec 1999 | A |
| 6016445 | Baura | Jan 2000 | A |
| 6026320 | Carlson et al. | Feb 2000 | A |
| 6029085 | Olson et al. | Feb 2000 | A |
| 6041250 | DePinto | Mar 2000 | A |
| 6044298 | Salo et al. | Mar 2000 | A |
| 6044300 | Gray | Mar 2000 | A |
| 6055454 | Heemels | Apr 2000 | A |
| 6066126 | Li et al. | May 2000 | A |
| 6073050 | Griffith | Jun 2000 | A |
| 6076016 | Feierbach | Jun 2000 | A |
| 6077236 | Cunningham | Jun 2000 | A |
| 6080187 | Alt et al. | Jun 2000 | A |
| 6083248 | Thompson | Jul 2000 | A |
| 6106551 | Crossett et al. | Aug 2000 | A |
| 6115636 | Ryan | Sep 2000 | A |
| 6128526 | Stadler et al. | Oct 2000 | A |
| 6141581 | Olson et al. | Oct 2000 | A |
| 6141588 | Cox et al. | Oct 2000 | A |
| 6141592 | Pauly | Oct 2000 | A |
| 6144879 | Gray | Nov 2000 | A |
| 6162195 | Igo et al. | Dec 2000 | A |
| 6164284 | Schulman et al. | Dec 2000 | A |
| 6167310 | Grevious | Dec 2000 | A |
| 6201993 | Kruse et al. | Mar 2001 | B1 |
| 6208894 | Schulman et al. | Mar 2001 | B1 |
| 6211799 | Post et al. | Apr 2001 | B1 |
| 6221011 | Bardy | Apr 2001 | B1 |
| 6240316 | Richmond et al. | May 2001 | B1 |
| 6240317 | Villaseca et al. | May 2001 | B1 |
| 6256534 | Dahl | Jul 2001 | B1 |
| 6259947 | Olson et al. | Jul 2001 | B1 |
| 6266558 | Gozani et al. | Jul 2001 | B1 |
| 6266567 | Ishikawa et al. | Jul 2001 | B1 |
| 6270457 | Bardy | Aug 2001 | B1 |
| 6272377 | Sweeney et al. | Aug 2001 | B1 |
| 6273856 | Sun et al. | Aug 2001 | B1 |
| 6277072 | Bardy | Aug 2001 | B1 |
| 6280380 | Bardy | Aug 2001 | B1 |
| 6285907 | Kramer et al. | Sep 2001 | B1 |
| 6292698 | Duffin et al. | Sep 2001 | B1 |
| 6295473 | Rosar | Sep 2001 | B1 |
| 6297943 | Carson | Oct 2001 | B1 |
| 6298271 | Weijand | Oct 2001 | B1 |
| 6307751 | Bodony et al. | Oct 2001 | B1 |
| 6312378 | Bardy | Nov 2001 | B1 |
| 6315721 | Schulman et al. | Nov 2001 | B2 |
| 6336903 | Bardy | Jan 2002 | B1 |
| 6345202 | Richmond et al. | Feb 2002 | B2 |
| 6351667 | Godie | Feb 2002 | B1 |
| 6351669 | Hartley et al. | Feb 2002 | B1 |
| 6353759 | Hartley et al. | Mar 2002 | B1 |
| 6358203 | Bardy | Mar 2002 | B2 |
| 6361780 | Ley et al. | Mar 2002 | B1 |
| 6368284 | Bardy | Apr 2002 | B1 |
| 6371922 | Baumann et al. | Apr 2002 | B1 |
| 6398728 | Bardy | Jun 2002 | B1 |
| 6400982 | Sweeney et al. | Jun 2002 | B2 |
| 6400990 | Silvian | Jun 2002 | B1 |
| 6408208 | Sun | Jun 2002 | B1 |
| 6409674 | Brockway et al. | Jun 2002 | B1 |
| 6411848 | Kramer et al. | Jun 2002 | B2 |
| 6424865 | Ding | Jul 2002 | B1 |
| 6434429 | Kraus et al. | Aug 2002 | B1 |
| 6438410 | Hsu et al. | Aug 2002 | B2 |
| 6438417 | Rockwell et al. | Aug 2002 | B1 |
| 6438421 | Stahmann et al. | Aug 2002 | B1 |
| 6440066 | Bardy | Aug 2002 | B1 |
| 6441747 | Khair et al. | Aug 2002 | B1 |
| 6442426 | Kroll | Aug 2002 | B1 |
| 6442432 | Lee | Aug 2002 | B2 |
| 6443891 | Grevious | Sep 2002 | B1 |
| 6445953 | Bulkes et al. | Sep 2002 | B1 |
| 6453200 | Koslar | Sep 2002 | B1 |
| 6459929 | Hopper et al. | Oct 2002 | B1 |
| 6470215 | Kraus et al. | Oct 2002 | B1 |
| 6471645 | Warkentin et al. | Oct 2002 | B1 |
| 6480745 | Nelson et al. | Nov 2002 | B2 |
| 6487443 | Olson et al. | Nov 2002 | B2 |
| 6490487 | Kraus et al. | Dec 2002 | B1 |
| 6498951 | Larson et al. | Dec 2002 | B1 |
| 6507755 | Gozani et al. | Jan 2003 | B1 |
| 6507759 | Prutchi et al. | Jan 2003 | B1 |
| 6512940 | Brabec et al. | Jan 2003 | B1 |
| 6522915 | Ceballos et al. | Feb 2003 | B1 |
| 6526311 | Begemann | Feb 2003 | B2 |
| 6539253 | Thompson et al. | Mar 2003 | B2 |
| 6542775 | Ding et al. | Apr 2003 | B2 |
| 6553258 | Stahmann et al. | Apr 2003 | B2 |
| 6561975 | Pool et al. | May 2003 | B1 |
| 6564807 | Schulman et al. | May 2003 | B1 |
| 6574506 | Kramer et al. | Jun 2003 | B2 |
| 6584351 | Ekwall | Jun 2003 | B1 |
| 6584352 | Combs et al. | Jun 2003 | B2 |
| 6597948 | Rockwell et al. | Jul 2003 | B1 |
| 6597951 | Kramer et al. | Jul 2003 | B2 |
| 6622046 | Fraley et al. | Sep 2003 | B2 |
| 6628985 | Sweeney et al. | Sep 2003 | B2 |
| 6647292 | Bardy et al. | Nov 2003 | B1 |
| 6666844 | Igo et al. | Dec 2003 | B1 |
| 6689117 | Sweeney et al. | Feb 2004 | B2 |
| 6690959 | Thompson | Feb 2004 | B2 |
| 6694189 | Begemann | Feb 2004 | B2 |
| 6704602 | Berg et al. | Mar 2004 | B2 |
| 6718212 | Parry et al. | Apr 2004 | B2 |
| 6721597 | Bardy et al. | Apr 2004 | B1 |
| 6738670 | Almendinger et al. | May 2004 | B1 |
| 6746797 | Benson et al. | Jun 2004 | B2 |
| 6749566 | Russ | Jun 2004 | B2 |
| 6758810 | Lebel et al. | Jul 2004 | B2 |
| 6763269 | Cox | Jul 2004 | B2 |
| 6778860 | Ostroff et al. | Aug 2004 | B2 |
| 6788971 | Sloman et al. | Sep 2004 | B1 |
| 6788974 | Bardy et al. | Sep 2004 | B2 |
| 6804558 | Haller et al. | Oct 2004 | B2 |
| 6807442 | Myklebust et al. | Oct 2004 | B1 |
| 6847844 | Sun et al. | Jan 2005 | B2 |
| 6871095 | Stahmann et al. | Mar 2005 | B2 |
| 6878112 | Linberg et al. | Apr 2005 | B2 |
| 6885889 | Chinchoy | Apr 2005 | B2 |
| 6892094 | Ousdigian et al. | May 2005 | B2 |
| 6897788 | Khair et al. | May 2005 | B2 |
| 6904315 | Panken et al. | Jun 2005 | B2 |
| 6922592 | Thompson et al. | Jul 2005 | B2 |
| 6931282 | Esler | Aug 2005 | B2 |
| 6934585 | Schloss et al. | Aug 2005 | B1 |
| 6957107 | Rogers et al. | Oct 2005 | B2 |
| 6978176 | Lattouf | Dec 2005 | B2 |
| 6985773 | Von Arx et al. | Jan 2006 | B2 |
| 6990375 | Kloss et al. | Jan 2006 | B2 |
| 7001366 | Ballard | Feb 2006 | B2 |
| 7003350 | Denker et al. | Feb 2006 | B2 |
| 7006864 | Echt et al. | Feb 2006 | B2 |
| 7013178 | Reinke et al. | Mar 2006 | B2 |
| 7027871 | Burnes et al. | Apr 2006 | B2 |
| 7050849 | Echt et al. | May 2006 | B2 |
| 7060031 | Webb et al. | Jun 2006 | B2 |
| 7063693 | Guenst | Jun 2006 | B2 |
| 7082336 | Ransbury et al. | Jul 2006 | B2 |
| 7085606 | Flach et al. | Aug 2006 | B2 |
| 7092758 | Sun et al. | Aug 2006 | B2 |
| 7110824 | Amundson et al. | Sep 2006 | B2 |
| 7120504 | Osypka | Oct 2006 | B2 |
| 7130681 | Gebhardt et al. | Oct 2006 | B2 |
| 7139613 | Reinke et al. | Nov 2006 | B2 |
| 7142912 | Wagner et al. | Nov 2006 | B2 |
| 7146225 | Guenst et al. | Dec 2006 | B2 |
| 7146226 | Lau et al. | Dec 2006 | B2 |
| 7149581 | Goedeke | Dec 2006 | B2 |
| 7149588 | Lau et al. | Dec 2006 | B2 |
| 7158839 | Lau | Jan 2007 | B2 |
| 7162307 | Patrias | Jan 2007 | B2 |
| 7164952 | Lau et al. | Jan 2007 | B2 |
| 7177700 | Cox | Feb 2007 | B1 |
| 7181505 | Haller et al. | Feb 2007 | B2 |
| 7184830 | Echt et al. | Feb 2007 | B2 |
| 7186214 | Ness | Mar 2007 | B2 |
| 7191015 | Lamson et al. | Mar 2007 | B2 |
| 7200437 | Nabutovsky et al. | Apr 2007 | B1 |
| 7200439 | Zdeblick et al. | Apr 2007 | B2 |
| 7206423 | Feng et al. | Apr 2007 | B1 |
| 7209785 | Kim et al. | Apr 2007 | B2 |
| 7209790 | Thompson et al. | Apr 2007 | B2 |
| 7211884 | Davis et al. | May 2007 | B1 |
| 7212871 | Morgan | May 2007 | B1 |
| 7226440 | Gelfand et al. | Jun 2007 | B2 |
| 7228183 | Sun et al. | Jun 2007 | B2 |
| 7236821 | Cates et al. | Jun 2007 | B2 |
| 7236829 | Farazi et al. | Jun 2007 | B1 |
| 7254448 | Almendinger et al. | Aug 2007 | B2 |
| 7260436 | Kilgore et al. | Aug 2007 | B2 |
| 7270669 | Sra | Sep 2007 | B1 |
| 7272448 | Morgan et al. | Sep 2007 | B1 |
| 7277755 | Falkenberg et al. | Oct 2007 | B1 |
| 7280872 | Mosesov et al. | Oct 2007 | B1 |
| 7288096 | Chin | Oct 2007 | B2 |
| 7289847 | Gill et al. | Oct 2007 | B1 |
| 7289852 | Helfinstine et al. | Oct 2007 | B2 |
| 7289853 | Campbell et al. | Oct 2007 | B1 |
| 7289855 | Nghiem et al. | Oct 2007 | B2 |
| 7302294 | Kamath et al. | Nov 2007 | B2 |
| 7305266 | Kroll | Dec 2007 | B1 |
| 7310556 | Bulkes | Dec 2007 | B2 |
| 7319905 | Morgan et al. | Jan 2008 | B1 |
| 7321798 | Muhlenberg et al. | Jan 2008 | B2 |
| 7333853 | Mazar et al. | Feb 2008 | B2 |
| 7336994 | Hettrick et al. | Feb 2008 | B2 |
| 7347819 | Lebel et al. | Mar 2008 | B2 |
| 7366572 | Heruth et al. | Apr 2008 | B2 |
| 7373207 | Lattouf | May 2008 | B2 |
| 7384403 | Sherman | Jun 2008 | B2 |
| 7386342 | Falkenberg et al. | Jun 2008 | B1 |
| 7392090 | Sweeney et al. | Jun 2008 | B2 |
| 7406105 | DelMain et al. | Jul 2008 | B2 |
| 7406349 | Seeberger et al. | Jul 2008 | B2 |
| 7410497 | Hastings et al. | Aug 2008 | B2 |
| 7425200 | Brockway et al. | Sep 2008 | B2 |
| 7433739 | Salys et al. | Oct 2008 | B1 |
| 7496409 | Greenhut et al. | Feb 2009 | B2 |
| 7496410 | Heil | Feb 2009 | B2 |
| 7502652 | Gaunt et al. | Mar 2009 | B2 |
| 7512448 | Malick et al. | Mar 2009 | B2 |
| 7515969 | Tockman et al. | Apr 2009 | B2 |
| 7526342 | Chin et al. | Apr 2009 | B2 |
| 7529589 | Williams et al. | May 2009 | B2 |
| 7532933 | Hastings et al. | May 2009 | B2 |
| 7536222 | Bardy et al. | May 2009 | B2 |
| 7536224 | Ritscher et al. | May 2009 | B2 |
| 7539541 | Quiles et al. | May 2009 | B2 |
| 7544197 | Kelsch et al. | Jun 2009 | B2 |
| 7558631 | Cowan et al. | Jul 2009 | B2 |
| 7565195 | Kroll et al. | Jul 2009 | B1 |
| 7584002 | Burnes et al. | Sep 2009 | B2 |
| 7590455 | Heruth et al. | Sep 2009 | B2 |
| 7606621 | Brisken et al. | Oct 2009 | B2 |
| 7610088 | Chinchoy | Oct 2009 | B2 |
| 7610092 | Cowan et al. | Oct 2009 | B2 |
| 7610099 | Almendinger et al. | Oct 2009 | B2 |
| 7610104 | Kaplan et al. | Oct 2009 | B2 |
| 7616991 | Mann et al. | Nov 2009 | B2 |
| 7617001 | Penner et al. | Nov 2009 | B2 |
| 7617007 | Williams et al. | Nov 2009 | B2 |
| 7630767 | Poore et al. | Dec 2009 | B1 |
| 7634313 | Kroll et al. | Dec 2009 | B1 |
| 7637867 | Zdeblick | Dec 2009 | B2 |
| 7640060 | Zdeblick | Dec 2009 | B2 |
| 7647109 | Hastings et al. | Jan 2010 | B2 |
| 7650186 | Hastings et al. | Jan 2010 | B2 |
| 7657311 | Bardy et al. | Feb 2010 | B2 |
| 7668596 | Von Arx et al. | Feb 2010 | B2 |
| 7682316 | Anderson et al. | Mar 2010 | B2 |
| 7691047 | Ferrari | Apr 2010 | B2 |
| 7702392 | Echt et al. | Apr 2010 | B2 |
| 7713194 | Zdeblick | May 2010 | B2 |
| 7713195 | Zdeblick | May 2010 | B2 |
| 7729783 | Michels et al. | Jun 2010 | B2 |
| 7734333 | Ghanem et al. | Jun 2010 | B2 |
| 7734343 | Ransbury et al. | Jun 2010 | B2 |
| 7738958 | Zdeblick et al. | Jun 2010 | B2 |
| 7738964 | Von Arx et al. | Jun 2010 | B2 |
| 7742812 | Ghanem et al. | Jun 2010 | B2 |
| 7742816 | Masoud et al. | Jun 2010 | B2 |
| 7742822 | Masoud et al. | Jun 2010 | B2 |
| 7743151 | Vallapureddy et al. | Jun 2010 | B2 |
| 7747335 | Williams | Jun 2010 | B2 |
| 7751881 | Cowan et al. | Jul 2010 | B2 |
| 7758521 | Morris et al. | Jul 2010 | B2 |
| 7761150 | Ghanem et al. | Jul 2010 | B2 |
| 7761164 | Verhoef et al. | Jul 2010 | B2 |
| 7765001 | Echt et al. | Jul 2010 | B2 |
| 7769452 | Ghanem et al. | Aug 2010 | B2 |
| 7783362 | Whitehurst et al. | Aug 2010 | B2 |
| 7792588 | Harding | Sep 2010 | B2 |
| 7797059 | Bornzin et al. | Sep 2010 | B1 |
| 7801596 | Fischell et al. | Sep 2010 | B2 |
| 7809438 | Echt et al. | Oct 2010 | B2 |
| 7840281 | Kveen et al. | Nov 2010 | B2 |
| 7844331 | Li et al. | Nov 2010 | B2 |
| 7844348 | Swoyer et al. | Nov 2010 | B2 |
| 7846088 | Ness | Dec 2010 | B2 |
| 7848815 | Brisken et al. | Dec 2010 | B2 |
| 7848823 | Drasler et al. | Dec 2010 | B2 |
| 7860455 | Fukumoto et al. | Dec 2010 | B2 |
| 7871433 | Lattouf | Jan 2011 | B2 |
| 7877136 | Moffitt et al. | Jan 2011 | B1 |
| 7877142 | Moaddeb et al. | Jan 2011 | B2 |
| 7881786 | Jackson | Feb 2011 | B2 |
| 7881798 | Miesel et al. | Feb 2011 | B2 |
| 7881810 | Chitre et al. | Feb 2011 | B1 |
| 7890173 | Brisken et al. | Feb 2011 | B2 |
| 7890181 | Denzene et al. | Feb 2011 | B2 |
| 7890192 | Kelsch et al. | Feb 2011 | B1 |
| 7894885 | Bartal et al. | Feb 2011 | B2 |
| 7894894 | Stadler et al. | Feb 2011 | B2 |
| 7894907 | Cowan et al. | Feb 2011 | B2 |
| 7894910 | Cowan et al. | Feb 2011 | B2 |
| 7894915 | Chitre et al. | Feb 2011 | B1 |
| 7899537 | Kroll et al. | Mar 2011 | B1 |
| 7899541 | Cowan et al. | Mar 2011 | B2 |
| 7899542 | Cowan et al. | Mar 2011 | B2 |
| 7899554 | Williams et al. | Mar 2011 | B2 |
| 7901360 | Yang et al. | Mar 2011 | B1 |
| 7904170 | Harding | Mar 2011 | B2 |
| 7907993 | Ghanem et al. | Mar 2011 | B2 |
| 7920928 | Yang et al. | Apr 2011 | B1 |
| 7925343 | Min et al. | Apr 2011 | B1 |
| 7930022 | Zhang et al. | Apr 2011 | B2 |
| 7930040 | Kelsch et al. | Apr 2011 | B1 |
| 7937135 | Ghanem et al. | May 2011 | B2 |
| 7937148 | Jacobson | May 2011 | B2 |
| 7937161 | Hastings et al. | May 2011 | B2 |
| 7941214 | Kleckner et al. | May 2011 | B2 |
| 7945333 | Jacobson | May 2011 | B2 |
| 7946997 | Hübinette | May 2011 | B2 |
| 7949404 | Hill | May 2011 | B2 |
| 7949405 | Feher | May 2011 | B2 |
| 7953486 | Daum et al. | May 2011 | B2 |
| 7953493 | Fowler et al. | May 2011 | B2 |
| 7962202 | Bhunia | Jun 2011 | B2 |
| 7974702 | Fain et al. | Jul 2011 | B1 |
| 7979136 | Young et al. | Jul 2011 | B2 |
| 7983753 | Severin | Jul 2011 | B2 |
| 3000791 | Sunagawa et al. | Aug 2011 | A1 |
| 3000807 | Morris et al. | Aug 2011 | A1 |
| 3001975 | DiSilvestro et al. | Aug 2011 | A1 |
| 3002700 | Ferek-Petric et al. | Aug 2011 | A1 |
| 7991467 | Markowitz et al. | Aug 2011 | B2 |
| 7991471 | Ghanem et al. | Aug 2011 | B2 |
| 7996087 | Cowan et al. | Aug 2011 | B2 |
| 8010209 | Jacobson | Aug 2011 | B2 |
| 8019419 | Panescu et al. | Sep 2011 | B1 |
| 8019434 | Quiles et al. | Sep 2011 | B2 |
| 8027727 | Freeberg | Sep 2011 | B2 |
| 8027729 | Sunagawa et al. | Sep 2011 | B2 |
| 8032219 | Neumann et al. | Oct 2011 | B2 |
| 8036743 | Savage et al. | Oct 2011 | B2 |
| 8046079 | Bange et al. | Oct 2011 | B2 |
| 8046080 | Von Arx et al. | Oct 2011 | B2 |
| 3055350 | Roberts | Nov 2011 | A1 |
| 3060212 | Rios et al. | Nov 2011 | A1 |
| 3065018 | Haubrich et al. | Nov 2011 | A1 |
| 8050297 | DelMain et al. | Nov 2011 | B2 |
| 8050759 | Stegemann et al. | Nov 2011 | B2 |
| 8050774 | Kveen et al. | Nov 2011 | B2 |
| 8055345 | Li et al. | Nov 2011 | B2 |
| 8073542 | Doerr | Dec 2011 | B2 |
| 8078278 | Penner | Dec 2011 | B2 |
| 8078283 | Cowan et al. | Dec 2011 | B2 |
| 8095123 | Gray | Jan 2012 | B2 |
| 8102789 | Rosar et al. | Jan 2012 | B2 |
| 8103359 | Reddy | Jan 2012 | B2 |
| 8103361 | Moser | Jan 2012 | B2 |
| 8112148 | Giftakis et al. | Feb 2012 | B2 |
| 8114021 | Robertson et al. | Feb 2012 | B2 |
| 8121680 | Falkenberg et al. | Feb 2012 | B2 |
| 8123684 | Zdeblick | Feb 2012 | B2 |
| 8126545 | Flach et al. | Feb 2012 | B2 |
| 8131334 | Lu et al. | Mar 2012 | B2 |
| 8140161 | Willerton et al. | Mar 2012 | B2 |
| 8150521 | Crowley et al. | Apr 2012 | B2 |
| 8160672 | Kim et al. | Apr 2012 | B2 |
| 8160702 | Mann et al. | Apr 2012 | B2 |
| 8160704 | Freeberg | Apr 2012 | B2 |
| 8165694 | Carbanaru et al. | Apr 2012 | B2 |
| 8175715 | Cox | May 2012 | B1 |
| 8180451 | Hickman et al. | May 2012 | B2 |
| 8185213 | Kveen et al. | May 2012 | B2 |
| 8187161 | Li et al. | May 2012 | B2 |
| 8195293 | Limousin et al. | Jun 2012 | B2 |
| 8204595 | Pianca et al. | Jun 2012 | B2 |
| 8204605 | Hastings et al. | Jun 2012 | B2 |
| 8209014 | Doerr | Jun 2012 | B2 |
| 8214043 | Matos | Jul 2012 | B2 |
| 8224244 | Kim et al. | Jul 2012 | B2 |
| 8229556 | Li | Jul 2012 | B2 |
| 8233985 | Bulkes et al. | Jul 2012 | B2 |
| 8262578 | Bharmi et al. | Sep 2012 | B1 |
| 8265748 | Liu et al. | Sep 2012 | B2 |
| 8265757 | Mass et al. | Sep 2012 | B2 |
| 8280521 | Haubrich et al. | Oct 2012 | B2 |
| 8285387 | Utsi et al. | Oct 2012 | B2 |
| 8290598 | Boon et al. | Oct 2012 | B2 |
| 8290600 | Hastings et al. | Oct 2012 | B2 |
| 8295939 | Jacobson | Oct 2012 | B2 |
| 8301254 | Mosesov et al. | Oct 2012 | B2 |
| 8315701 | Cowan et al. | Nov 2012 | B2 |
| 8315708 | Berthelsdorf et al. | Nov 2012 | B2 |
| 8321021 | Kisker et al. | Nov 2012 | B2 |
| 8321036 | Brockway et al. | Nov 2012 | B2 |
| 8332036 | Hastings et al. | Dec 2012 | B2 |
| 8335563 | Stessman | Dec 2012 | B2 |
| 8335568 | Heruth et al. | Dec 2012 | B2 |
| 8340750 | Prakash et al. | Dec 2012 | B2 |
| 8340780 | Hastings et al. | Dec 2012 | B2 |
| 8352025 | Jacobson | Jan 2013 | B2 |
| 8352028 | Wenger | Jan 2013 | B2 |
| 8352038 | Mao et al. | Jan 2013 | B2 |
| 8359098 | Lund et al. | Jan 2013 | B2 |
| 8364261 | Stubbs et al. | Jan 2013 | B2 |
| 8364276 | Willis | Jan 2013 | B2 |
| 8369959 | Meskens | Feb 2013 | B2 |
| 8369962 | Abrahamson | Feb 2013 | B2 |
| 8380320 | Spital | Feb 2013 | B2 |
| 8386051 | Rys | Feb 2013 | B2 |
| 8391981 | Mosesov | Mar 2013 | B2 |
| 8391990 | Smith et al. | Mar 2013 | B2 |
| 8406874 | Liu et al. | Mar 2013 | B2 |
| 8406879 | Shuros et al. | Mar 2013 | B2 |
| 8406886 | Gaunt et al. | Mar 2013 | B2 |
| 8412352 | Griswold et al. | Apr 2013 | B2 |
| 8417340 | Goossen | Apr 2013 | B2 |
| 8417341 | Freeberg | Apr 2013 | B2 |
| 8423149 | Hennig | Apr 2013 | B2 |
| 8428722 | Verhoef et al. | Apr 2013 | B2 |
| 8433402 | Ruben et al. | Apr 2013 | B2 |
| 8433409 | Johnson et al. | Apr 2013 | B2 |
| 8433420 | Bange et al. | Apr 2013 | B2 |
| 8447412 | Dal Molin et al. | May 2013 | B2 |
| 8452413 | Young et al. | May 2013 | B2 |
| 8457740 | Osche | Jun 2013 | B2 |
| 8457742 | Jacobson | Jun 2013 | B2 |
| 8457744 | Janzig et al. | Jun 2013 | B2 |
| 8457761 | Wariar | Jun 2013 | B2 |
| 8478407 | Demmer et al. | Jul 2013 | B2 |
| 8478408 | Hastings et al. | Jul 2013 | B2 |
| 8478431 | Griswold et al. | Jul 2013 | B2 |
| 8494632 | Sun et al. | Jul 2013 | B2 |
| 8504156 | Bonner et al. | Aug 2013 | B2 |
| 8509910 | Sowder et al. | Aug 2013 | B2 |
| 8515559 | Roberts et al. | Aug 2013 | B2 |
| 8525340 | Eckhardt et al. | Sep 2013 | B2 |
| 8527068 | Ostroff | Sep 2013 | B2 |
| 8532790 | Griswold | Sep 2013 | B2 |
| 8538526 | Stahmann et al. | Sep 2013 | B2 |
| 8541131 | Lund et al. | Sep 2013 | B2 |
| 8543205 | Ostroff | Sep 2013 | B2 |
| 8547248 | Zdeblick et al. | Oct 2013 | B2 |
| 8548605 | Ollivier | Oct 2013 | B2 |
| 8554333 | Wu et al. | Oct 2013 | B2 |
| 8565882 | Matos | Oct 2013 | B2 |
| 8565897 | Regnier et al. | Oct 2013 | B2 |
| 8571678 | Wang | Oct 2013 | B2 |
| 8577327 | Makdissi et al. | Nov 2013 | B2 |
| 8588926 | Moore et al. | Nov 2013 | B2 |
| 8612002 | Faltys et al. | Dec 2013 | B2 |
| 8615310 | Khairkhahan et al. | Dec 2013 | B2 |
| 8626280 | Allavatam et al. | Jan 2014 | B2 |
| 8626294 | Sheldon et al. | Jan 2014 | B2 |
| 8634908 | Cowan | Jan 2014 | B2 |
| 8634912 | Bomzin et al. | Jan 2014 | B2 |
| 8634919 | Hou et al. | Jan 2014 | B1 |
| 8639335 | Peichel et al. | Jan 2014 | B2 |
| 8644934 | Hastings et al. | Feb 2014 | B2 |
| 8649859 | Smith et al. | Feb 2014 | B2 |
| 8670842 | Bornzin et al. | Mar 2014 | B1 |
| 8676319 | Knoll | Mar 2014 | B2 |
| 8676335 | Katoozi et al. | Mar 2014 | B2 |
| 8700173 | Edlund | Apr 2014 | B2 |
| 8700181 | Bornzin et al. | Apr 2014 | B2 |
| 8705599 | dal Molin et al. | Apr 2014 | B2 |
| 8718766 | Wahlberg | May 2014 | B2 |
| 8718773 | Willis et al. | May 2014 | B2 |
| 8725260 | Shuros et al. | May 2014 | B2 |
| 8738133 | Shuros et al. | May 2014 | B2 |
| 8738147 | Hastings et al. | May 2014 | B2 |
| 8744555 | Allavatam et al. | Jun 2014 | B2 |
| 8744572 | Greenhut et al. | Jun 2014 | B1 |
| 8747314 | Stahmann et al. | Jun 2014 | B2 |
| 8755884 | Demmer et al. | Jun 2014 | B2 |
| 8758365 | Bonner et al. | Jun 2014 | B2 |
| 8768483 | Schmitt et al. | Jul 2014 | B2 |
| 8774572 | Hamamoto | Jul 2014 | B2 |
| 8781605 | Bornzin et al. | Jul 2014 | B2 |
| 8788035 | Jacobson | Jul 2014 | B2 |
| 8788053 | Jacobson | Jul 2014 | B2 |
| 8798740 | Samade et al. | Aug 2014 | B2 |
| 8798745 | Jacobson | Aug 2014 | B2 |
| 8798762 | Fain et al. | Aug 2014 | B2 |
| 8798770 | Reddy | Aug 2014 | B2 |
| 8805505 | Roberts | Aug 2014 | B1 |
| 8805528 | Corndorf | Aug 2014 | B2 |
| 8812109 | Blomqvist et al. | Aug 2014 | B2 |
| 8818504 | Bodner et al. | Aug 2014 | B2 |
| 8827913 | Havel et al. | Sep 2014 | B2 |
| 8831747 | Min et al. | Sep 2014 | B1 |
| 8855789 | Jacobson | Oct 2014 | B2 |
| 8868186 | Kroll | Oct 2014 | B2 |
| 8886339 | Faltys et al. | Nov 2014 | B2 |
| 8903473 | Rogers et al. | Dec 2014 | B2 |
| 8903500 | Smith et al. | Dec 2014 | B2 |
| 8903513 | Ollivier | Dec 2014 | B2 |
| 8909336 | Navarro-Paredes et al. | Dec 2014 | B2 |
| 8914131 | Bornzin et al. | Dec 2014 | B2 |
| 8923795 | Makdissi et al. | Dec 2014 | B2 |
| 8923963 | Bonner et al. | Dec 2014 | B2 |
| 8938300 | Rosero | Jan 2015 | B2 |
| 8942806 | Sheldon et al. | Jan 2015 | B2 |
| 8958892 | Khairkhahan et al. | Feb 2015 | B2 |
| 8977358 | Ewert et al. | Mar 2015 | B2 |
| 8989873 | Locsin | Mar 2015 | B2 |
| 8996109 | Karst et al. | Mar 2015 | B2 |
| 9002467 | Smith et al. | Apr 2015 | B2 |
| 9008776 | Cowan et al. | Apr 2015 | B2 |
| 9008777 | Dianaty et al. | Apr 2015 | B2 |
| 9014818 | Deterre et al. | Apr 2015 | B2 |
| 9017341 | Bornzin et al. | Apr 2015 | B2 |
| 9020611 | Khairkhahan et al. | Apr 2015 | B2 |
| 9037262 | Regnier et al. | May 2015 | B2 |
| 9042984 | Demmer et al. | May 2015 | B2 |
| 9072911 | Hastings et al. | Jul 2015 | B2 |
| 9072913 | Jacobson | Jul 2015 | B2 |
| 9155882 | Grubac et al. | Oct 2015 | B2 |
| 9168372 | Fain | Oct 2015 | B2 |
| 9168380 | Greenhut et al. | Oct 2015 | B1 |
| 9168383 | Jacobson et al. | Oct 2015 | B2 |
| 9180285 | Moore et al. | Nov 2015 | B2 |
| 9192774 | Jacobson | Nov 2015 | B2 |
| 9205225 | Khairkhahan et al. | Dec 2015 | B2 |
| 9216285 | Boling et al. | Dec 2015 | B1 |
| 9216293 | Berthiaume et al. | Dec 2015 | B2 |
| 9216298 | Jacobson | Dec 2015 | B2 |
| 9227077 | Jacobson | Jan 2016 | B2 |
| 9238145 | Wenzel et al. | Jan 2016 | B2 |
| 9242102 | Khairkhahan et al. | Jan 2016 | B2 |
| 9242113 | Smith et al. | Jan 2016 | B2 |
| 9248300 | Rys et al. | Feb 2016 | B2 |
| 9265436 | Min et al. | Feb 2016 | B2 |
| 9265962 | Dianaty et al. | Feb 2016 | B2 |
| 9272155 | Ostroff | Mar 2016 | B2 |
| 9278218 | Karst et al. | Mar 2016 | B2 |
| 9278229 | Reinke et al. | Mar 2016 | B1 |
| 9283381 | Grubac et al. | Mar 2016 | B2 |
| 9283382 | Berthiaume et al. | Mar 2016 | B2 |
| 9289612 | Sambelashvili et al. | Mar 2016 | B1 |
| 9302115 | Molin et al. | Apr 2016 | B2 |
| 9333364 | Echt et al. | May 2016 | B2 |
| 9358387 | Suwito et al. | Jun 2016 | B2 |
| 9358400 | Jacobson | Jun 2016 | B2 |
| 9364675 | Deterre et al. | Jun 2016 | B2 |
| 9370663 | Moulder | Jun 2016 | B2 |
| 9375580 | Bonner et al. | Jun 2016 | B2 |
| 9375581 | Baru et al. | Jun 2016 | B2 |
| 9381365 | Kibler et al. | Jul 2016 | B2 |
| 9393424 | Demmer et al. | Jul 2016 | B2 |
| 9393436 | Doerr | Jul 2016 | B2 |
| 9399139 | Demmer et al. | Jul 2016 | B2 |
| 9399140 | Cho et al. | Jul 2016 | B2 |
| 9409033 | Jacobson | Aug 2016 | B2 |
| 9427594 | Bornzin et al. | Aug 2016 | B1 |
| 9433368 | Stahmann et al. | Sep 2016 | B2 |
| 9433780 | Régnier et al. | Sep 2016 | B2 |
| 9457193 | Klimovitch et al. | Oct 2016 | B2 |
| 9492668 | Sheldon et al. | Nov 2016 | B2 |
| 9492669 | Demmer et al. | Nov 2016 | B2 |
| 9492674 | Schmidt et al. | Nov 2016 | B2 |
| 9492677 | Greenhut et al. | Nov 2016 | B2 |
| 9511233 | Sambelashvili | Dec 2016 | B2 |
| 9511236 | Varady et al. | Dec 2016 | B2 |
| 9511237 | Deterre et al. | Dec 2016 | B2 |
| 9522276 | Shen et al. | Dec 2016 | B2 |
| 9522280 | Fishier et al. | Dec 2016 | B2 |
| 9526522 | Wood et al. | Dec 2016 | B2 |
| 9526891 | Eggen et al. | Dec 2016 | B2 |
| 9526909 | Stahmann et al. | Dec 2016 | B2 |
| 9533163 | Klimovitch et al. | Jan 2017 | B2 |
| 9561382 | Persson et al. | Feb 2017 | B2 |
| 9566012 | Greenhut et al. | Feb 2017 | B2 |
| 9636511 | Carney et al. | May 2017 | B2 |
| 9669223 | Auricchio et al. | Jun 2017 | B2 |
| 9687654 | Sheldon et al. | Jun 2017 | B2 |
| 9687655 | Pertijs et al. | Jun 2017 | B2 |
| 9687659 | Von Arx et al. | Jun 2017 | B2 |
| 9694186 | Carney et al. | Jul 2017 | B2 |
| 9782594 | Stahmann et al. | Oct 2017 | B2 |
| 9782601 | Ludwig | Oct 2017 | B2 |
| 9789317 | Greenhut et al. | Oct 2017 | B2 |
| 9789319 | Sambelashvili | Oct 2017 | B2 |
| 9808617 | Ostroff et al. | Nov 2017 | B2 |
| 9808628 | Sheldon et al. | Nov 2017 | B2 |
| 9808631 | Maile et al. | Nov 2017 | B2 |
| 9808632 | Reinke et al. | Nov 2017 | B2 |
| 9808633 | Bonner et al. | Nov 2017 | B2 |
| 9808637 | Sharma et al. | Nov 2017 | B2 |
| 9855414 | Marshall et al. | Jan 2018 | B2 |
| 9855430 | Ghosh et al. | Jan 2018 | B2 |
| 9855435 | Sahabi et al. | Jan 2018 | B2 |
| 9861815 | Tran et al. | Jan 2018 | B2 |
| 10080887 | Schmidt et al. | Sep 2018 | B2 |
| 10080888 | Kelly et al. | Sep 2018 | B2 |
| 10080900 | Ghosh et al. | Sep 2018 | B2 |
| 10080903 | Willis et al. | Sep 2018 | B2 |
| 10086206 | Sambelashvili | Oct 2018 | B2 |
| 10118026 | Grubac et al. | Nov 2018 | B2 |
| 10124163 | Ollivier et al. | Nov 2018 | B2 |
| 10124175 | Berthiaume et al. | Nov 2018 | B2 |
| 10130821 | Grubac et al. | Nov 2018 | B2 |
| 10137305 | Kane et al. | Nov 2018 | B2 |
| 10201710 | Jackson et al. | Feb 2019 | B2 |
| 10207115 | Echt et al. | Feb 2019 | B2 |
| 10207116 | Sheldon et al. | Feb 2019 | B2 |
| 10226197 | Reinke et al. | Mar 2019 | B2 |
| 10226639 | Zhang | Mar 2019 | B2 |
| 10232182 | Hareland et al. | Mar 2019 | B2 |
| 10265503 | Schmidt et al. | Apr 2019 | B2 |
| 10265534 | Greenhut et al. | Apr 2019 | B2 |
| 10271752 | Regnier et al. | Apr 2019 | B2 |
| 10278601 | Greenhut et al. | May 2019 | B2 |
| 10279165 | Seifert et al. | May 2019 | B2 |
| 10286221 | Sawchuk | May 2019 | B2 |
| 10307598 | Ciciarelli et al. | Jun 2019 | B2 |
| 10328274 | Zhang et al. | Jun 2019 | B2 |
| 10342981 | Ghosh et al. | Jul 2019 | B2 |
| 20020032470 | Linberg | Mar 2002 | A1 |
| 20020035376 | Bardy et al. | Mar 2002 | A1 |
| 20020035377 | Bardy et al. | Mar 2002 | A1 |
| 20020035378 | Bardy et al. | Mar 2002 | A1 |
| 20020035380 | Rissmann et al. | Mar 2002 | A1 |
| 20020035381 | Bardy et al. | Mar 2002 | A1 |
| 20020042629 | Bardy et al. | Apr 2002 | A1 |
| 20020042630 | Bardy et al. | Apr 2002 | A1 |
| 20020042634 | Bardy et al. | Apr 2002 | A1 |
| 20020049475 | Bardy et al. | Apr 2002 | A1 |
| 20020052636 | Bardy et al. | May 2002 | A1 |
| 20020068958 | Bardy et al. | Jun 2002 | A1 |
| 20020072773 | Bardy et al. | Jun 2002 | A1 |
| 20020082665 | Haller et al. | Jun 2002 | A1 |
| 20020091414 | Bardy et al. | Jul 2002 | A1 |
| 20020095196 | Linberg | Jul 2002 | A1 |
| 20020099423 | Berg et al. | Jul 2002 | A1 |
| 20020103454 | Sackner et al. | Aug 2002 | A1 |
| 20020103510 | Bardy et al. | Aug 2002 | A1 |
| 20020107545 | Rissmann et al. | Aug 2002 | A1 |
| 20020107546 | Ostroff et al. | Aug 2002 | A1 |
| 20020107547 | Edinger et al. | Aug 2002 | A1 |
| 20020107548 | Bardy et al. | Aug 2002 | A1 |
| 20020107549 | Bardy et al. | Aug 2002 | A1 |
| 20020107559 | Sanders et al. | Aug 2002 | A1 |
| 20020120299 | Ostroff et al. | Aug 2002 | A1 |
| 20020173830 | Starkweather et al. | Nov 2002 | A1 |
| 20020193846 | Pool et al. | Dec 2002 | A1 |
| 20030009203 | Lebel et al. | Jan 2003 | A1 |
| 20030028082 | Thompson | Feb 2003 | A1 |
| 20030040779 | Engmark et al. | Feb 2003 | A1 |
| 20030041866 | Linberg et al. | Mar 2003 | A1 |
| 20030045805 | Sheldon et al. | Mar 2003 | A1 |
| 20030088278 | Bardy et al. | May 2003 | A1 |
| 20030097153 | Bardy et al. | May 2003 | A1 |
| 20030105497 | Zhu et al. | Jun 2003 | A1 |
| 20030114908 | Flach | Jun 2003 | A1 |
| 20030120337 | Van Tassel et al. | Jun 2003 | A1 |
| 20030144701 | Mehra et al. | Jul 2003 | A1 |
| 20030187460 | Chin et al. | Oct 2003 | A1 |
| 20030187461 | Chin | Oct 2003 | A1 |
| 20030191526 | Van Tassel et al. | Oct 2003 | A1 |
| 20030195572 | Bocek et al. | Oct 2003 | A1 |
| 20030204145 | Manolas | Oct 2003 | A1 |
| 20040024435 | Leckrone et al. | Feb 2004 | A1 |
| 20040068302 | Rodgers et al. | Apr 2004 | A1 |
| 20040087938 | Leckrone et al. | May 2004 | A1 |
| 20040088035 | Guenst et al. | May 2004 | A1 |
| 20040102830 | Williams | May 2004 | A1 |
| 20040127959 | Amundson et al. | Jul 2004 | A1 |
| 20040133242 | Chapman et al. | Jul 2004 | A1 |
| 20040147969 | Mann et al. | Jul 2004 | A1 |
| 20040147973 | Hauser | Jul 2004 | A1 |
| 20040167558 | Igo et al. | Aug 2004 | A1 |
| 20040167587 | Thompson | Aug 2004 | A1 |
| 20040172071 | Bardy et al. | Sep 2004 | A1 |
| 20040172077 | Chinchoy | Sep 2004 | A1 |
| 20040172104 | Berg et al. | Sep 2004 | A1 |
| 20040176817 | Wahlstrand et al. | Sep 2004 | A1 |
| 20040176818 | Wahlstrand et al. | Sep 2004 | A1 |
| 20040176830 | Fang | Sep 2004 | A1 |
| 20040186529 | Bardy et al. | Sep 2004 | A1 |
| 20040204673 | Flaherty | Oct 2004 | A1 |
| 20040210292 | Bardy et al. | Oct 2004 | A1 |
| 20040210293 | Bardy et al. | Oct 2004 | A1 |
| 20040210294 | Bardy et al. | Oct 2004 | A1 |
| 20040215308 | Bardy et al. | Oct 2004 | A1 |
| 20040220624 | Ritscher et al. | Nov 2004 | A1 |
| 20040220626 | Wagner | Nov 2004 | A1 |
| 20040220639 | Mulligan et al. | Nov 2004 | A1 |
| 20040230283 | Prinzen et al. | Nov 2004 | A1 |
| 20040249431 | Ransbury et al. | Dec 2004 | A1 |
| 20040260348 | Bakken et al. | Dec 2004 | A1 |
| 20040267303 | Guenst | Dec 2004 | A1 |
| 20050061320 | Lee et al. | Mar 2005 | A1 |
| 20050070962 | Echt et al. | Mar 2005 | A1 |
| 20050102003 | Grabek et al. | May 2005 | A1 |
| 20050137634 | Hall et al. | Jun 2005 | A1 |
| 20050149138 | Min et al. | Jul 2005 | A1 |
| 20050165466 | Morris et al. | Jul 2005 | A1 |
| 20050182465 | Ness | Aug 2005 | A1 |
| 20050203410 | Jenkins | Sep 2005 | A1 |
| 20050283208 | Von Arx et al. | Dec 2005 | A1 |
| 20050288743 | Ahn et al. | Dec 2005 | A1 |
| 20060042830 | Maghribi et al. | Mar 2006 | A1 |
| 20060052829 | Sun et al. | Mar 2006 | A1 |
| 20060052830 | Spinelli et al. | Mar 2006 | A1 |
| 20060064135 | Brockway | Mar 2006 | A1 |
| 20060064149 | Belacazar et al. | Mar 2006 | A1 |
| 20060085039 | Hastings et al. | Apr 2006 | A1 |
| 20060085041 | Hastings et al. | Apr 2006 | A1 |
| 20060085042 | Hastings et al. | Apr 2006 | A1 |
| 20060095078 | Tronnes | May 2006 | A1 |
| 20060106442 | Richardson et al. | May 2006 | A1 |
| 20060116746 | Chin | Jun 2006 | A1 |
| 20060135999 | Bodner et al. | Jun 2006 | A1 |
| 20060136004 | Cowan et al. | Jun 2006 | A1 |
| 20060155338 | Mongeon et al. | Jul 2006 | A1 |
| 20060161061 | Echt et al. | Jul 2006 | A1 |
| 20060200002 | Guenst | Sep 2006 | A1 |
| 20060206151 | Lu | Sep 2006 | A1 |
| 20060212079 | Routh et al. | Sep 2006 | A1 |
| 20060228452 | Cromack et al. | Oct 2006 | A1 |
| 20060228453 | Cromack et al. | Oct 2006 | A1 |
| 20060240070 | Cromack et al. | Oct 2006 | A1 |
| 20060241701 | Markowitz et al. | Oct 2006 | A1 |
| 20060241705 | Neumann et al. | Oct 2006 | A1 |
| 20060247672 | Vidlund et al. | Nov 2006 | A1 |
| 20060259088 | Pastore et al. | Nov 2006 | A1 |
| 20060265018 | Smith et al. | Nov 2006 | A1 |
| 20060293715 | Plicchi et al. | Dec 2006 | A1 |
| 20070004979 | Wojciechowicz et al. | Jan 2007 | A1 |
| 20070016098 | Kim et al. | Jan 2007 | A1 |
| 20070027508 | Cowan | Feb 2007 | A1 |
| 20070060787 | Peters et al. | Mar 2007 | A1 |
| 20070078490 | Cowan et al. | Apr 2007 | A1 |
| 20070088394 | Jacobson | Apr 2007 | A1 |
| 20070088396 | Jacobson | Apr 2007 | A1 |
| 20070088397 | Jacobson | Apr 2007 | A1 |
| 20070088398 | Jacobson | Apr 2007 | A1 |
| 20070088405 | Jacobson | Apr 2007 | A1 |
| 20070135882 | Drasler et al. | Jun 2007 | A1 |
| 20070135883 | Drasler et al. | Jun 2007 | A1 |
| 20070150037 | Hastings et al. | Jun 2007 | A1 |
| 20070150038 | Hastings et al. | Jun 2007 | A1 |
| 20070156190 | Cinbis | Jul 2007 | A1 |
| 20070179541 | Prakash et al. | Aug 2007 | A1 |
| 20070219525 | Gelfand et al. | Sep 2007 | A1 |
| 20070219590 | Hastings et al. | Sep 2007 | A1 |
| 20070225545 | Ferrari | Sep 2007 | A1 |
| 20070233206 | Frikart et al. | Oct 2007 | A1 |
| 20070239210 | Libbus et al. | Oct 2007 | A1 |
| 20070239244 | Morgan et al. | Oct 2007 | A1 |
| 20070255376 | Michels et al. | Nov 2007 | A1 |
| 20070276444 | Gelbart et al. | Nov 2007 | A1 |
| 20070293900 | Sheldon et al. | Dec 2007 | A1 |
| 20070293904 | Gelbart et al. | Dec 2007 | A1 |
| 20080004663 | Jorgenson | Jan 2008 | A1 |
| 20080009791 | Cohen et al. | Jan 2008 | A1 |
| 20080009910 | Kraetschmer et al. | Jan 2008 | A1 |
| 20080010024 | Diamond | Jan 2008 | A1 |
| 20080021505 | Hastings et al. | Jan 2008 | A1 |
| 20080021519 | De Geest et al. | Jan 2008 | A1 |
| 20080021532 | Kveen et al. | Jan 2008 | A1 |
| 20080065183 | Whitehurst et al. | Mar 2008 | A1 |
| 20080065185 | Worley | Mar 2008 | A1 |
| 20080071318 | Brooke et al. | Mar 2008 | A1 |
| 20080109054 | Hastings et al. | May 2008 | A1 |
| 20080119911 | Rosero | May 2008 | A1 |
| 20080130670 | Kim et al. | Jun 2008 | A1 |
| 20080154139 | Shuros et al. | Jun 2008 | A1 |
| 20080154322 | Jackson et al. | Jun 2008 | A1 |
| 20080228234 | Stancer | Sep 2008 | A1 |
| 20080234771 | Chinchoy et al. | Sep 2008 | A1 |
| 20080243217 | Wildon | Oct 2008 | A1 |
| 20080269814 | Rosero | Oct 2008 | A1 |
| 20080269825 | Chinchoy et al. | Oct 2008 | A1 |
| 20080275518 | Ghanem et al. | Nov 2008 | A1 |
| 20080275519 | Ghanem et al. | Nov 2008 | A1 |
| 20080288039 | Reddy | Nov 2008 | A1 |
| 20080294208 | Willis et al. | Nov 2008 | A1 |
| 20080294210 | Rosero | Nov 2008 | A1 |
| 20080294217 | Lian et al. | Nov 2008 | A1 |
| 20080294229 | Friedman et al. | Nov 2008 | A1 |
| 20080306359 | Zdeblick et al. | Dec 2008 | A1 |
| 20090018599 | Hastings et al. | Jan 2009 | A1 |
| 20090024180 | Kisker et al. | Jan 2009 | A1 |
| 20090036941 | Corbucci | Feb 2009 | A1 |
| 20090048646 | Katoozi et al. | Feb 2009 | A1 |
| 20090062895 | Stahmann et al. | Mar 2009 | A1 |
| 20090082827 | Kveen et al. | Mar 2009 | A1 |
| 20090082828 | Ostroff | Mar 2009 | A1 |
| 20090088648 | Jaffe et al. | Apr 2009 | A1 |
| 20090088813 | Brockway et al. | Apr 2009 | A1 |
| 20090112285 | Cahan et al. | Apr 2009 | A1 |
| 20090131907 | Chin et al. | May 2009 | A1 |
| 20090135886 | Robertson et al. | May 2009 | A1 |
| 20090143835 | Pastore et al. | Jun 2009 | A1 |
| 20090149908 | Bjorling et al. | Jun 2009 | A1 |
| 20090171408 | Solem | Jul 2009 | A1 |
| 20090171414 | Kelly et al. | Jul 2009 | A1 |
| 20090204163 | Shuros et al. | Aug 2009 | A1 |
| 20090204170 | Hastings et al. | Aug 2009 | A1 |
| 20090210024 | M. | Aug 2009 | A1 |
| 20090216292 | Pless et al. | Aug 2009 | A1 |
| 20090216317 | Cromack et al. | Aug 2009 | A1 |
| 20090234407 | Hastings et al. | Sep 2009 | A1 |
| 20090234411 | Sambelashvili et al. | Sep 2009 | A1 |
| 20090266573 | Engmark et al. | Oct 2009 | A1 |
| 20090275998 | Burnes et al. | Nov 2009 | A1 |
| 20090275999 | Burnes et al. | Nov 2009 | A1 |
| 20090299424 | Narayan | Dec 2009 | A1 |
| 20090299447 | Jensen et al. | Dec 2009 | A1 |
| 20100013668 | Kantervik | Jan 2010 | A1 |
| 20100016911 | Willis et al. | Jan 2010 | A1 |
| 20100023085 | Wu et al. | Jan 2010 | A1 |
| 20100030061 | Canfield et al. | Feb 2010 | A1 |
| 20100030327 | Chatel | Feb 2010 | A1 |
| 20100042108 | Hibino | Feb 2010 | A1 |
| 20100056871 | Govari et al. | Mar 2010 | A1 |
| 20100063375 | Kassab et al. | Mar 2010 | A1 |
| 20100063562 | Cowan et al. | Mar 2010 | A1 |
| 20100069983 | Peacock, III et al. | Mar 2010 | A1 |
| 20100094274 | Narayan et al. | Apr 2010 | A1 |
| 20100094367 | Sen | Apr 2010 | A1 |
| 20100114209 | Krause et al. | May 2010 | A1 |
| 20100114214 | Morelli et al. | May 2010 | A1 |
| 20100125281 | Jacobson et al. | May 2010 | A1 |
| 20100131027 | Sathaye et al. | May 2010 | A1 |
| 20100168761 | Kassab et al. | Jul 2010 | A1 |
| 20100168819 | Freeberg | Jul 2010 | A1 |
| 20100174333 | Dewals | Jul 2010 | A1 |
| 20100198288 | Ostroff | Aug 2010 | A1 |
| 20100198289 | Kameli et al. | Aug 2010 | A1 |
| 20100198304 | Wang | Aug 2010 | A1 |
| 20100217367 | Belson | Aug 2010 | A1 |
| 20100228308 | Cowan et al. | Sep 2010 | A1 |
| 20100234906 | Koh | Sep 2010 | A1 |
| 20100234924 | Willis | Sep 2010 | A1 |
| 20100241185 | Mahapatra et al. | Sep 2010 | A1 |
| 20100249729 | Morris et al. | Sep 2010 | A1 |
| 20100268040 | Ben-Oren et al. | Oct 2010 | A1 |
| 20100286744 | Echt et al. | Nov 2010 | A1 |
| 20100298841 | Prinzen et al. | Nov 2010 | A1 |
| 20100312309 | Harding | Dec 2010 | A1 |
| 20110022113 | Zdeblick et al. | Jan 2011 | A1 |
| 20110071586 | Jacobson | Mar 2011 | A1 |
| 20110077708 | Ostroff | Mar 2011 | A1 |
| 20110112600 | Cowan et al. | May 2011 | A1 |
| 20110118588 | Komblau et al. | May 2011 | A1 |
| 20110118810 | Cowan et al. | May 2011 | A1 |
| 20110137187 | Yang et al. | Jun 2011 | A1 |
| 20110144720 | Cowan et al. | Jun 2011 | A1 |
| 20110152970 | Jollota et al. | Jun 2011 | A1 |
| 20110160558 | Rassatt et al. | Jun 2011 | A1 |
| 20110160565 | Stubbs et al. | Jun 2011 | A1 |
| 20110160801 | Markowitz et al. | Jun 2011 | A1 |
| 20110160806 | Lyden et al. | Jun 2011 | A1 |
| 20110166620 | Cowan et al. | Jul 2011 | A1 |
| 20110166621 | Cowan et al. | Jul 2011 | A1 |
| 20110184491 | Kivi | Jul 2011 | A1 |
| 20110190835 | Brockway et al. | Aug 2011 | A1 |
| 20110202099 | Makdissi | Aug 2011 | A1 |
| 20110208260 | Jacobson | Aug 2011 | A1 |
| 20110218587 | Jacobson | Sep 2011 | A1 |
| 20110230734 | Fain et al. | Sep 2011 | A1 |
| 20110237967 | Moore et al. | Sep 2011 | A1 |
| 20110245890 | Brisben et al. | Oct 2011 | A1 |
| 20110251660 | Griswold | Oct 2011 | A1 |
| 20110251662 | Griswold et al. | Oct 2011 | A1 |
| 20110270099 | Ruben et al. | Nov 2011 | A1 |
| 20110270339 | Murray, III et al. | Nov 2011 | A1 |
| 20110270340 | Pellegrini et al. | Nov 2011 | A1 |
| 20110270341 | Ruben et al. | Nov 2011 | A1 |
| 20110276102 | Cohen | Nov 2011 | A1 |
| 20110282423 | Jacobson | Nov 2011 | A1 |
| 20120004527 | Thompson et al. | Jan 2012 | A1 |
| 20120029323 | Zhao | Feb 2012 | A1 |
| 20120041508 | Rousso et al. | Feb 2012 | A1 |
| 20120059433 | Cowan et al. | Mar 2012 | A1 |
| 20120059436 | Fontaine et al. | Mar 2012 | A1 |
| 20120065500 | Rogers et al. | Mar 2012 | A1 |
| 20120065597 | Cohen | Mar 2012 | A1 |
| 20120078322 | Dal Molin et al. | Mar 2012 | A1 |
| 20120089198 | Ostroff | Apr 2012 | A1 |
| 20120093245 | Makdissi et al. | Apr 2012 | A1 |
| 20120095521 | Hintz | Apr 2012 | A1 |
| 20120095539 | Khairkhahan et al. | Apr 2012 | A1 |
| 20120101540 | O'Brien et al. | Apr 2012 | A1 |
| 20120101553 | Reddy | Apr 2012 | A1 |
| 20120109148 | Bonner et al. | May 2012 | A1 |
| 20120109149 | Bonner et al. | May 2012 | A1 |
| 20120109236 | Jacobson et al. | May 2012 | A1 |
| 20120109259 | Bond et al. | May 2012 | A1 |
| 20120116489 | Khairkhahan et al. | May 2012 | A1 |
| 20120150251 | Giftakis et al. | Jun 2012 | A1 |
| 20120158111 | Khairkhahan et al. | Jun 2012 | A1 |
| 20120165827 | Khairkhahan et al. | Jun 2012 | A1 |
| 20120172690 | Anderson et al. | Jul 2012 | A1 |
| 20120172891 | Lee | Jul 2012 | A1 |
| 20120172892 | Grubac et al. | Jul 2012 | A1 |
| 20120172942 | Berg | Jul 2012 | A1 |
| 20120197350 | Roberts et al. | Aug 2012 | A1 |
| 20120197373 | Khairkhahan et al. | Aug 2012 | A1 |
| 20120215285 | Tahmasian et al. | Aug 2012 | A1 |
| 20120232565 | Kveen et al. | Sep 2012 | A1 |
| 20120245665 | Friedman et al. | Sep 2012 | A1 |
| 20120277600 | Greenhut | Nov 2012 | A1 |
| 20120277606 | Ellingson et al. | Nov 2012 | A1 |
| 20120283795 | Stancer et al. | Nov 2012 | A1 |
| 20120283807 | Deterre et al. | Nov 2012 | A1 |
| 20120289776 | Keast et al. | Nov 2012 | A1 |
| 20120289815 | Keast et al. | Nov 2012 | A1 |
| 20120290021 | Saurkar et al. | Nov 2012 | A1 |
| 20120290025 | Keimel | Nov 2012 | A1 |
| 20120296381 | Matos | Nov 2012 | A1 |
| 20120303082 | Dong et al. | Nov 2012 | A1 |
| 20120316613 | Keefe et al. | Dec 2012 | A1 |
| 20130012151 | Hankins | Jan 2013 | A1 |
| 20130023975 | Locsin | Jan 2013 | A1 |
| 20130035748 | Bonner et al. | Feb 2013 | A1 |
| 20130041422 | Jacobson | Feb 2013 | A1 |
| 20130053908 | Smith et al. | Feb 2013 | A1 |
| 20130053915 | Holmstrom et al. | Feb 2013 | A1 |
| 20130053921 | Bonner et al. | Feb 2013 | A1 |
| 20130060298 | Splett et al. | Mar 2013 | A1 |
| 20130066169 | Rys et al. | Mar 2013 | A1 |
| 20130072770 | Rao et al. | Mar 2013 | A1 |
| 20130079798 | Tran et al. | Mar 2013 | A1 |
| 20130079861 | Reinert et al. | Mar 2013 | A1 |
| 20130085350 | Schugt et al. | Apr 2013 | A1 |
| 20130085403 | Gunderson et al. | Apr 2013 | A1 |
| 20130085550 | Polefko et al. | Apr 2013 | A1 |
| 20130090702 | Mongeon et al. | Apr 2013 | A1 |
| 20130096649 | Martin et al. | Apr 2013 | A1 |
| 20130103047 | Steingisser et al. | Apr 2013 | A1 |
| 20130103109 | Jacobson | Apr 2013 | A1 |
| 20130110008 | Bourget et al. | May 2013 | A1 |
| 20130110127 | Bornzin et al. | May 2013 | A1 |
| 20130110192 | Tran et al. | May 2013 | A1 |
| 20130110219 | Bornzin et al. | May 2013 | A1 |
| 20130116529 | Min et al. | May 2013 | A1 |
| 20130116738 | Samade et al. | May 2013 | A1 |
| 20130116740 | Bornzin et al. | May 2013 | A1 |
| 20130116741 | Bornzin et al. | May 2013 | A1 |
| 20130123872 | Bornzin et al. | May 2013 | A1 |
| 20130123875 | Varady et al. | May 2013 | A1 |
| 20130131591 | Berthiaume et al. | May 2013 | A1 |
| 20130131693 | Berthiaume et al. | May 2013 | A1 |
| 20130131750 | Stadler et al. | May 2013 | A1 |
| 20130138006 | Bornzin et al. | May 2013 | A1 |
| 20130150695 | Biela et al. | Jun 2013 | A1 |
| 20130150911 | Perschbacher et al. | Jun 2013 | A1 |
| 20130150912 | Perschbacher et al. | Jun 2013 | A1 |
| 20130184776 | Shuros et al. | Jul 2013 | A1 |
| 20130192611 | Taepke, II et al. | Aug 2013 | A1 |
| 20130196703 | Masoud et al. | Aug 2013 | A1 |
| 20130197609 | Moore et al. | Aug 2013 | A1 |
| 20130204312 | Gill et al. | Aug 2013 | A1 |
| 20130231710 | Jacobson | Sep 2013 | A1 |
| 20130238072 | Deterre et al. | Sep 2013 | A1 |
| 20130238073 | Makdissi et al. | Sep 2013 | A1 |
| 20130253309 | Allan et al. | Sep 2013 | A1 |
| 20130253342 | Griswold et al. | Sep 2013 | A1 |
| 20130253343 | Waldhauser et al. | Sep 2013 | A1 |
| 20130253344 | Griswold et al. | Sep 2013 | A1 |
| 20130253345 | Griswold et al. | Sep 2013 | A1 |
| 20130253346 | Griswold et al. | Sep 2013 | A1 |
| 20130253347 | Griswold et al. | Sep 2013 | A1 |
| 20130261497 | Pertijs et al. | Oct 2013 | A1 |
| 20130265144 | Banna et al. | Oct 2013 | A1 |
| 20130268042 | Hastings et al. | Oct 2013 | A1 |
| 20130274828 | Willis | Oct 2013 | A1 |
| 20130274847 | Ostroff | Oct 2013 | A1 |
| 20130282070 | Cowan et al. | Oct 2013 | A1 |
| 20130282073 | Cowan et al. | Oct 2013 | A1 |
| 20130296727 | Sullivan et al. | Nov 2013 | A1 |
| 20130303872 | Taff et al. | Nov 2013 | A1 |
| 20130324825 | Ostroff et al. | Dec 2013 | A1 |
| 20130325081 | Karst | Dec 2013 | A1 |
| 20130345770 | Dianaty et al. | Dec 2013 | A1 |
| 20140012344 | Hastings et al. | Jan 2014 | A1 |
| 20140018690 | Carlson et al. | Jan 2014 | A1 |
| 20140018876 | Ostroff | Jan 2014 | A1 |
| 20140018877 | Demmer et al. | Jan 2014 | A1 |
| 20140031836 | Ollivier | Jan 2014 | A1 |
| 20140039570 | Carroll et al. | Feb 2014 | A1 |
| 20140039591 | Drasler et al. | Feb 2014 | A1 |
| 20140043146 | Makdissi et al. | Feb 2014 | A1 |
| 20140046395 | Regnier et al. | Feb 2014 | A1 |
| 20140046420 | Moore et al. | Feb 2014 | A1 |
| 20140058240 | Mothilal et al. | Feb 2014 | A1 |
| 20140058494 | Ostroff et al. | Feb 2014 | A1 |
| 20140074114 | Khairkhahan et al. | Mar 2014 | A1 |
| 20140074186 | Faltys et al. | Mar 2014 | A1 |
| 20140094676 | Gani et al. | Apr 2014 | A1 |
| 20140094891 | Pare et al. | Apr 2014 | A1 |
| 20140100624 | Ellingson | Apr 2014 | A1 |
| 20140100627 | Min | Apr 2014 | A1 |
| 20140107723 | Hou et al. | Apr 2014 | A1 |
| 20140121719 | Bonner et al. | May 2014 | A1 |
| 20140121720 | Bonner et al. | May 2014 | A1 |
| 20140121722 | Sheldon et al. | May 2014 | A1 |
| 20140128935 | Kumar et al. | May 2014 | A1 |
| 20140135865 | Hastings et al. | May 2014 | A1 |
| 20140142648 | Smith et al. | May 2014 | A1 |
| 20140148675 | Nordstrom et al. | May 2014 | A1 |
| 20140148815 | Wenzel et al. | May 2014 | A1 |
| 20140155950 | Hastings et al. | Jun 2014 | A1 |
| 20140169162 | Romano et al. | Jun 2014 | A1 |
| 20140172060 | Bomzin et al. | Jun 2014 | A1 |
| 20140180306 | Grubac et al. | Jun 2014 | A1 |
| 20140180366 | Edlund | Jun 2014 | A1 |
| 20140207149 | Hastings et al. | Jul 2014 | A1 |
| 20140207210 | Willis et al. | Jul 2014 | A1 |
| 20140214104 | Greenhut et al. | Jul 2014 | A1 |
| 20140222015 | Keast et al. | Aug 2014 | A1 |
| 20140222098 | Baru et al. | Aug 2014 | A1 |
| 20140222109 | Moulder | Aug 2014 | A1 |
| 20140228696 | Narayan et al. | Aug 2014 | A1 |
| 20140228913 | Molin et al. | Aug 2014 | A1 |
| 20140236172 | Hastings et al. | Aug 2014 | A1 |
| 20140243848 | Auricchio et al. | Aug 2014 | A1 |
| 20140255298 | Cole et al. | Sep 2014 | A1 |
| 20140257324 | Fain | Sep 2014 | A1 |
| 20140257422 | Herken | Sep 2014 | A1 |
| 20140257444 | Cole et al. | Sep 2014 | A1 |
| 20140276929 | Foster et al. | Sep 2014 | A1 |
| 20140277237 | Maskara et al. | Sep 2014 | A1 |
| 20140303704 | Suwito et al. | Oct 2014 | A1 |
| 20140309706 | Jacobson | Oct 2014 | A1 |
| 20140343348 | Kaplan et al. | Nov 2014 | A1 |
| 20140371818 | Bond et al. | Dec 2014 | A1 |
| 20140379041 | Foster | Dec 2014 | A1 |
| 20150025612 | Haasl et al. | Jan 2015 | A1 |
| 20150031966 | Ward et al. | Jan 2015 | A1 |
| 20150038962 | Cohen | Feb 2015 | A1 |
| 20150039041 | Smith et al. | Feb 2015 | A1 |
| 20150045868 | Bonner et al. | Feb 2015 | A1 |
| 20150051609 | Schmidt et al. | Feb 2015 | A1 |
| 20150051610 | Schmidt et al. | Feb 2015 | A1 |
| 20150051611 | Schmidt et al. | Feb 2015 | A1 |
| 20150051612 | Schmidt et al. | Feb 2015 | A1 |
| 20150051613 | Schmidt et al. | Feb 2015 | A1 |
| 20150051614 | Schmidt et al. | Feb 2015 | A1 |
| 20150051615 | Schmidt et al. | Feb 2015 | A1 |
| 20150051616 | Haasl et al. | Feb 2015 | A1 |
| 20150051682 | Schmidt et al. | Feb 2015 | A1 |
| 20150057520 | Foster et al. | Feb 2015 | A1 |
| 20150057558 | Stahmann et al. | Feb 2015 | A1 |
| 20150057721 | Stahmann et al. | Feb 2015 | A1 |
| 20150088155 | Stahmann et al. | Mar 2015 | A1 |
| 20150105836 | Bonner et al. | Apr 2015 | A1 |
| 20150112425 | Cromack et al. | Apr 2015 | A1 |
| 20150126854 | Keast et al. | May 2015 | A1 |
| 20150142069 | Sambelashvili | May 2015 | A1 |
| 20150157861 | Aghassian | Jun 2015 | A1 |
| 20150157866 | Demmer et al. | Jun 2015 | A1 |
| 20150173655 | Demmer et al. | Jun 2015 | A1 |
| 20150190638 | Smith et al. | Jul 2015 | A1 |
| 20150196756 | Stahmann et al. | Jul 2015 | A1 |
| 20150196757 | Stahmann et al. | Jul 2015 | A1 |
| 20150196758 | Stahmann et al. | Jul 2015 | A1 |
| 20150196769 | Stahmann et al. | Jul 2015 | A1 |
| 20150217119 | Nikolski et al. | Aug 2015 | A1 |
| 20150221898 | Chi et al. | Aug 2015 | A1 |
| 20150224315 | Stahmann | Aug 2015 | A1 |
| 20150224320 | Stahmann | Aug 2015 | A1 |
| 20150230699 | Berul et al. | Aug 2015 | A1 |
| 20150238769 | Demmer et al. | Aug 2015 | A1 |
| 20150258345 | Smith et al. | Sep 2015 | A1 |
| 20150290468 | Zhang | Oct 2015 | A1 |
| 20150297905 | Greenhut et al. | Oct 2015 | A1 |
| 20150297907 | Zhang | Oct 2015 | A1 |
| 20150305637 | Greenhut et al. | Oct 2015 | A1 |
| 20150305638 | Zhang | Oct 2015 | A1 |
| 20150305639 | Greenhut et al. | Oct 2015 | A1 |
| 20150305640 | Reinke et al. | Oct 2015 | A1 |
| 20150305641 | Stadler et al. | Oct 2015 | A1 |
| 20150305642 | Reinke et al. | Oct 2015 | A1 |
| 20150306374 | Seifert et al. | Oct 2015 | A1 |
| 20150306375 | Marshall et al. | Oct 2015 | A1 |
| 20150306401 | Demmer et al. | Oct 2015 | A1 |
| 20150306406 | Crutchfield et al. | Oct 2015 | A1 |
| 20150306407 | Crutchfield et al. | Oct 2015 | A1 |
| 20150306408 | Greenhut et al. | Oct 2015 | A1 |
| 20150321016 | O'Brien et al. | Nov 2015 | A1 |
| 20150328459 | Chin et al. | Nov 2015 | A1 |
| 20150335383 | Cohen | Nov 2015 | A9 |
| 20150335884 | Khairkhahan et al. | Nov 2015 | A1 |
| 20150342466 | Thakur et al. | Dec 2015 | A1 |
| 20150360041 | Stahmann et al. | Dec 2015 | A1 |
| 20160015322 | Anderson et al. | Jan 2016 | A1 |
| 20160023000 | Cho et al. | Jan 2016 | A1 |
| 20160030757 | Jacobson | Feb 2016 | A1 |
| 20160033177 | Barot et al. | Feb 2016 | A1 |
| 20160051823 | Maile et al. | Feb 2016 | A1 |
| 20160067486 | Brown et al. | Mar 2016 | A1 |
| 20160067490 | Carney | Mar 2016 | A1 |
| 20160114161 | Amblard et al. | Apr 2016 | A1 |
| 20160121127 | Klimovitch et al. | May 2016 | A1 |
| 20160121128 | Fishier et al. | May 2016 | A1 |
| 20160121129 | Persson et al. | May 2016 | A1 |
| 20160129262 | Sheldon | May 2016 | A1 |
| 20160144192 | Sanghera et al. | May 2016 | A1 |
| 20160213919 | Suwito et al. | Jul 2016 | A1 |
| 20160213937 | Reinke et al. | Jul 2016 | A1 |
| 20160213939 | Carney et al. | Jul 2016 | A1 |
| 20160228026 | Jackson | Aug 2016 | A1 |
| 20160262691 | Jain et al. | Sep 2016 | A1 |
| 20160270734 | Imhoff et al. | Sep 2016 | A1 |
| 20160278657 | Narayan et al. | Sep 2016 | A1 |
| 20160317825 | Jacobson | Nov 2016 | A1 |
| 20160367823 | Cowan et al. | Dec 2016 | A1 |
| 20170014629 | Ghosh et al. | Jan 2017 | A1 |
| 20170027458 | Glover et al. | Feb 2017 | A1 |
| 20170028203 | Ghosh | Feb 2017 | A1 |
| 20170035315 | Jackson | Feb 2017 | A1 |
| 20170043173 | Sharma et al. | Feb 2017 | A1 |
| 20170043174 | Greenhut et al. | Feb 2017 | A1 |
| 20170189681 | Anderson | Jul 2017 | A1 |
| 20170274213 | Ghosh et al. | Sep 2017 | A1 |
| 20170281261 | Shuros et al. | Oct 2017 | A1 |
| 20170281952 | Shuros et al. | Oct 2017 | A1 |
| 20170281953 | Min et al. | Oct 2017 | A1 |
| 20170281955 | Maile et al. | Oct 2017 | A1 |
| 20170312531 | Sawchuk | Nov 2017 | A1 |
| 20170368347 | Muessig | Dec 2017 | A1 |
| 20180008829 | An et al. | Jan 2018 | A1 |
| 20180021567 | An et al. | Jan 2018 | A1 |
| 20180021581 | An et al. | Jan 2018 | A1 |
| 20180021582 | An et al. | Jan 2018 | A1 |
| 20180256902 | Toy et al. | Sep 2018 | A1 |
| 20180256909 | Smith et al. | Sep 2018 | A1 |
| 20180264262 | Haasl et al. | Sep 2018 | A1 |
| 20180264270 | Koop et al. | Sep 2018 | A1 |
| 20180264272 | Haasl et al. | Sep 2018 | A1 |
| 20180264273 | Haasl et al. | Sep 2018 | A1 |
| 20180264274 | Haasl et al. | Sep 2018 | A1 |
| 20180339160 | Carroll | Nov 2018 | A1 |
| 20190167991 | Stahmann | Jun 2019 | A1 |
| Number | Date | Country |
|---|---|---|
| 2008279789 | Oct 2011 | AU |
| 2008329620 | May 2014 | AU |
| 2014203793 | Jul 2014 | AU |
| 1003904 | Jan 1977 | CA |
| 202933393 | May 2013 | CN |
| 104203340 | Dec 2014 | CN |
| 106535987 | Mar 2017 | CN |
| 0362611 | Apr 1990 | EP |
| 503823 | Sep 1992 | EP |
| 1702648 | Sep 2006 | EP |
| 1904166 | Jun 2011 | EP |
| 2471452 | Jul 2012 | EP |
| 2433675 | Jan 2013 | EP |
| 2441491 | Jan 2013 | EP |
| 2452721 | Nov 2013 | EP |
| 2662113 | Nov 2013 | EP |
| 1948296 | Jan 2014 | EP |
| 2760541 | May 2016 | EP |
| 2833966 | May 2016 | EP |
| 2000051373 | Feb 2000 | JP |
| 2002502640 | Jan 2002 | JP |
| 2004512105 | Apr 2004 | JP |
| 2005508208 | Mar 2005 | JP |
| 2005245215 | Sep 2005 | JP |
| 2008540040 | Nov 2008 | JP |
| 5199867 | Feb 2013 | JP |
| 9500202 | Jan 1995 | WO |
| 9636134 | Nov 1996 | WO |
| 9724981 | Jul 1997 | WO |
| 9826840 | Jun 1998 | WO |
| 9939767 | Aug 1999 | WO |
| 0234330 | May 2002 | WO |
| 02098282 | Dec 2002 | WO |
| 2005000206 | Jan 2005 | WO |
| 2005042089 | May 2005 | WO |
| 2006065394 | Jun 2006 | WO |
| 2006086435 | Aug 2006 | WO |
| 2006113659 | Oct 2006 | WO |
| 2006124833 | Nov 2006 | WO |
| 2007073435 | Jun 2007 | WO |
| 2007075974 | Jul 2007 | WO |
| 2009006531 | Jan 2009 | WO |
| 2012054102 | Apr 2012 | WO |
| 2013080038 | Jun 2013 | WO |
| 2013098644 | Jul 2013 | WO |
| 2013184787 | Dec 2013 | WO |
| 2014120769 | Aug 2014 | WO |
| 2016014352 | Jan 2016 | WO |
| Entry |
|---|
| US 8,886,318 B2, 11/2014, Jacobson et al. (withdrawn) |
| International Search Report and Written Opinion for Application No. PCT/US2018/063122, 14 pages, dated Feb. 14, 2019. |
| Chinitz et al; “Accelerometer-Based Atrioventricular Synchronus Pacing with a Ventricular Leadless Pacemaker: Results from the Micra Atrioventricular Feasibility Studies”, Heart Rhythm 15, pp. 1363-1371, 2018. |
| International Search Report and Written Opinion for Application No. PCT/US2018/062469, 12 pages, dated Feb. 26, 2019. |
| International Search Report and Written Opinion for Application No. PCT/US2018/062631, 13 pages, dated Feb. 5, 2019. |
| “Instructions for Use System 1, Leadless Cardiac Pacemaker (LCP) and Delivery Catheter,” Nanostim Leadless Pacemakers, pp. 1-28, 2013. |
| Hachisuka et al., “Development and Performance Analysis of an Intra-Body Communication Device,” The 12th International Conference on Solid State Sensors, Actuators and Microsystems, vol. 4A1.3, pp. 1722-1725, 2003. |
| Seyedi et al., “A Survey on Intrabody Communications for Body Area Network Application,” IEEE Transactions on Biomedical Engineering,vol. 60(8): 2067-2079, 2013. |
| Spickler et al., “Totally Self-Contained Intracardiac Pacemaker,” Journal of Electrocardiology, vol. 3(384): 324-331, 1970. |
| Wegmüller, “Intra-Body Communication for Biomedical Sensor Networks,” Diss. EIH, No. 17323,1-173, 2007. |
| Number | Date | Country | |
|---|---|---|---|
| 20190167991 A1 | Jun 2019 | US |
| Number | Date | Country | |
|---|---|---|---|
| 62593662 | Dec 2017 | US |
