Patent Application
20230149721
Implantable medical devices (IMDs), such as cardiac pacemakers, are often configured to be connected to leads. The leads include electrical conductors that extend through a lead body from a connector assembly provided at a proximal lead end to one or more electrodes located at the distal lead end or elsewhere along the length of the lead body. The conductors connect stimulation and/or sensing circuitry within the IMD housing to respective electrodes or other sensors on the lead.
Therapeutic electrical signals provided by the leads connected to the IMD may include pulses or shocks for pacing, cardioversion, or defibrillation. In some cases, an IMD senses intrinsic depolarizations of the heart, and controls delivery of therapeutic signals to the heart based on the sensed depolarizations. An IMD may also be used to conduct temporary cardiac pacing on a temporary basis (for example, up to about 90 days). Temporary pacing may be prescribed to patients who may have temporary conduction disturbances, such as following the end of an operative procedure, or as a bridge between permanent implants in cases of device or system infection. In some examples, conduction disturbances treatable using a temporary IMD may be the result of transcatheter aortic valve replacement (TAVR), or may be caused by alcohol septal ablation or Lyme carditis.
The implantation of an IMD, such as a temporary or permanent pacemaker, has typically required one or more custom support instruments such as, for example, a device programmer, to perform a number of confirmation checks on the IMD at the time of implant. These confirmation checks help to ensure that the IMD and leads are properly implanted and operational post implant procedure, and can be important to ensure that the system provides prescribed therapy to a patient beginning at the time of implant.
When a temporary or permanent IMD is implanted, in some cases the practitioner performing the implant procedure lacks experience, or performs the implant procedure infrequently. In other cases, the implant procedure may be performed at a location or under emergency conditions where the practitioner performing the implant procedure may not have access to custom device programming instruments. In such situations the practitioner may desire rapid feedback on whether the implantation procedure was performed successfully. In some examples, the most readily available feedback on proper implantation is a surface electrocardiogram (ECG), which, in the absence of a sophisticated external programmer, can be monitored by the clinician performing the implant procedure.
In general, the present disclosure is directed to techniques in which, after leads are attached to the IMD, the IMD triggers performance of diagnostic self-tests and provides rapid feedback to the practitioner to support the implant procedure. In some examples, following lead connection, the temporary or permanent IMD performs at least some of the following diagnostic tests: detection of qualification of connection to a pacing electrode(s), determination that the IMD is able to adequately sense intrinsic cardiac activity of the patient, determination that pacing operations generated by a signal generator or an implantable pulse generator (IPG) in the IMD are acceptable for implant, e.g., that pacing pulses capture the heart, and detection of proper lead fixation via assessment of current of injury (COI) parameters.
In some examples, the IMD performs periodic lead impedance monitoring to detect connection to electrodes, integrity of the lead, and/or connection of the electrodes to the heart. In some examples, detection of lead impedance in a valid range triggers other diagnostic tests such as monitoring a patient electrogram (EGM) to allow measurement of amplitudes alone or in combination with calculation of COI parameters. If the EGM amplitude and COI parameters are satisfied, the IMD may perform other test or measurements. In some examples, the IMD may lower a pacing rate, if necessary, to allow intrinsic conduction to determine EGM amplitudes, e.g., to confirm R-wave detection. In some examples, after EGM sensing has been confirmed, or it is determined that intrinsic conduction does not occur even when the pacing rate is lowered to threshold, e.g., indicating pacer dependency, IMD may perform capture tests to determine the pacing capture threshold (PCT), e.g., to determine whether the PCT is within an acceptable range for operation of the IMD.
In some examples, if the IMD does not itself make capture determinations, a clinician may observe the rhythm of the patient on an ECG monitor, and determine adequate R-wave sensing and device capture based on these observations. In some examples, the IMD confirms device capture by pacing the heart and detecting a signal confirming device capture. In some examples, IMD repeats the qualification test cycle for a predetermined period of time (for example, about 30 minutes) to provide continued monitoring of pacing and sensing effectiveness until (and in some cases after) the implantation procedure is complete (e.g., until or after skin closure). The IMD may provide confirmation of pacing and sensing effectiveness to a clinician via a confirmation signal, as described herein.
In some examples, the IMD performs these self-test algorithms without any external instrument or programming device, other than an optional ECG monitor that can display heart rate with some accuracy, and as such the method of the present disclosure can simplify the IMD implantation procedure and evaluation of device capture. In this manner, the techniques of this disclosure may improve the performance of the IMD during an implantation procedure or other performance evaluation, particularly in cases where custom support instruments may not be available.
In one aspect, the present disclosure is directed to an implantable medical device (IMD) configured to be coupled to at least one implantable medical lead, wherein the IMD comprises: sensing circuitry configured to sense an electrogram (EMG) signal of a patient via at least one electrode of the implantable medical lead; impedance measurement circuitry to measure impedance via the implantable medical lead; and a processor. The processor is configured, in response to coupling of the IMD to the at least one implantable medical lead, to initiate a device test sequence comprising a plurality of qualification tests over an evaluation period in which the processor: (1) controls the impedance measurement circuitry to measure an impedance for at least one electrical path that includes the at least one electrode to determine a connection status of the IMD to the at least one electrode; and (2) compares EGM (electrogram) amplitudes of the patient over an EGM test period against a predetermined threshold.
In another aspect, the present disclosure is directed to a method comprising detecting, by an implantable medical device (IMD), attachment to the IMD of at least one implantable medical lead, wherein the at least one implantable medical lead comprises at least one electrode, and triggering by the IMD, based on the detecting of the attachment to the IMD of the at least one medical lead, a device test sequence in which the IMD performs the following qualification tests over an evaluation period: (1) detecting an impedance for at least one electrical path that includes the at least one electrode to determine a connection status of the IMD to the at least one electrode; and (2) comparing EGM (electrogram) amplitudes of the patient over an EGM test period against a predetermined threshold.
In another aspect, the present disclosure is directed to a computer-readable medium comprising instructions that cause a processor to: following connection of the implantable medical device (IMD) to at least one lead, the lead including an electrode, controlling the IMD to automatically initiate, without input from an external programming device, a device test sequence in which the IMD performs the following qualification tests over an evaluation period: (1) detecting an impedance for at least one electrical path that includes the at least one electrode to determine a connection status of the IMD to the at least one electrode; and (2) comparing, over an EGM test period, cardiac sensed event amplitudes in an electrogram of the patient over an EGM test period against a predetermined threshold.
The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the disclosure will be apparent from the description and drawings, and from the claims.
Like symbols in the drawings indicate like elements.
In general, in this application an IMD is configured to perform a number of diagnostic tests following initial implantation in an automated fashion. In some examples, these diagnostic tests are performed by the IMD without input from an external programmer or other monitoring device. In some examples, the diagnostic tests performed by the IMD include periodic lead impedance monitoring to detect connection to electrodes, which in some examples is triggered by attachment of leads to the IMD. In some examples, detection of lead impedance in a valid range triggers measurement by the IMD of EGM amplitudes, and may include lowering the pacing rate generated by the IMD, if necessary, to uncover intrinsic signals, e.g., R-waves, in the EGM signals. In some examples, detection of lead impedance in a valid range can trigger measurement by the IMD of COI parameters. In some examples, after sensing of R-waves or another indication of adequate sensed EGM amplitudes, or it is determined that the patient does not have intrinsic conduction detectable at a lower escape interval, the IMD performs testing of pacing capture.
In some examples, the IMD presents a confirmation signal to the user based on successful completion of the test sequence, e.g., after determining an adequate pacing capture threshold. In some examples, the confirmation is observable on an ECG by a clinician as a fixed pacing rate, or pacing pattern such as, for example, alternating rates and/or alternating pacing outputs, over a predetermined time period. The confirmation cycle may repeat for a period of time (for example, about 30 minutes) to provide continued monitoring of pacing and sensing effectiveness as (and in some cases after) the implantation procedure is completed. The IMD may provide confirmation of pacing and sensing effectiveness to a clinician via a confirmation signal, as described herein.
A clinician may maneuver distal portion 120 through the vasculature of patient 116 to position distal portion 120 at or near target site 114. For example, the clinician may guide distal portion 120 through the superior vena cava (SVC) to target site 114 on or in a ventricular wall of heart 122, e.g., at the apex of the right ventricle as illustrated in
Implantable medical lead 112 may include electrodes 124A and 124B configured to be positioned on, within, or near cardiac tissue at or near target site 114, and a housing 127 of IMD 126 may include a housing electrode 124C. Electrodes 124A-124C may collectively be referred to “electrodes 124”, and the number and locations of electrodes 124 shown in
Electrodes 124 may be electrically connected to conductors (not shown) extending through lead body 118. In some examples, the conductors are electrically connected to therapy delivery circuitry of IMD 126, with the therapy delivery circuitry configured to provide electrical signals through the conductor to electrodes 124. Electrodes 124 may conduct the electrical signals to the target tissue of heart 122, causing the cardiac muscle, e.g., of the ventricles, to depolarize and, in turn, contract at a regular interval. Electrodes 124 may also be connected to sensing circuitry of IMD 126 via the conductors, and the sensing circuitry may sense activity of heart 122 via electrodes 124. Electrodes 124 may have various shapes such as tines, helices, screws, rings, and so on. Again, although a bipolar configuration of lead 112 including two electrodes 124 is illustrated in
In some examples, one or more housing electrodes 124C may be formed integrally with an outer surface of housing 127 or otherwise coupled to the housing 127. In some examples, housing electrode 124C is defined by an uninsulated portion of an outward facing portion of the housing 127 of the IMD 126. Other divisions between insulated and uninsulated portions of the housing 127 may be employed to define two or more housing electrodes. In some examples, the housing electrode 124C can include substantially all of the housing 127. Any of the electrodes 124A, 124B may be used for unipolar sensing or pacing in combination with the housing electrode 124C. As described in further detail with reference to
The configuration of the therapy system 100 illustrated in
In one or more examples, IMD 126 includes electronic circuitry contained within an enclosure where the circuitry may be configured to deliver cardiac pacing. In the example of
In some examples, the system 100 includes an optional programmer 130. For example, optional programmer 130 can be a handheld computing device such as a tablet or a phone, a computer workstation, or a networked computing device. The optional programmer 130 can include a user interface that receives input from a clinician, which can include a keypad and a suitable display such as, for example, a touch screen display, or a peripheral pointing device, such as a mouse, via which a user may interact with the user interface. The clinician may also interact with the programmer 130 remotely via a networked computing device.
The clinician, such as a physician, technician, surgeon, electrophysiologist, and the like, may in some cases interact with the programmer 130 to communicate with the IMD 126. For example, the clinician may interact with the programmer 130 to retrieve physiological or diagnostic information from the IMD 126. The clinician may also interact with the programmer 126 to program the IMD 126, e.g., select values for operational parameters of the IMD. In some examples, the programmer 130 may include an optional electrocardiogram (ECG) monitor.
The IMD 126 and the programmer 130 may communicate via wireless communication using any techniques known in the art. Examples of communication techniques may include, for example, low frequency or radiofrequency (RF) telemetry, but other techniques are also contemplated. In some examples, the IMD 126 may signal the programmer 130 to further communicate with and pass information through a network such as those available under the trade designation Medtronic CareLink Network from Medtronic, Inc., of Minneapolis, Minn., or some other network linking the patient 116 to a clinician.
In some examples, the system 100 includes an optional electrocardiogram (ECG) monitor 132. In some methods of the present disclosure, if the programmer 130 is not available, the EGC monitor 132 can provide a clinician with feedback regarding the rhythm and electrical activity of the heart following an IMD implantation procedure. In various examples, the ECG monitor can include one or more leads (not shown in
Processor 80 may include processing circuitry, such as any one or more of a microprocessor, a controller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or equivalent discrete or analog logic circuitry. In some examples, the processor 80 may include multiple components, such as any combination of one or more microprocessors, one or more controllers, one or more DSPs, one or more ASICs, or one or more FPGAs, as well as other discrete or integrated logic circuitry. The functions attributed to the processor 80 herein may be embodied as software, firmware, hardware or any combination thereof.
Processor 80 controls signal generator 84 to deliver therapy to heart 122 according to a selected one or more of therapy programs, which may be stored in memory 82. For example, processor 80 may control signal generator 84 to deliver electrical pulses with the amplitudes, pulse widths, frequency, or electrode polarities specified by the selected one or more therapy programs. As discussed in more detail below, processor 80 may control the signal generator to pace the heart in a number of different modes including, but not limited to, VOO, VVI, and OVO.
Signal generator 84 is electrically coupled to electrodes 124A, 124B, e.g., via conductors of lead 120, or, in the case of housing electrode 124C, via an electrical conductor disposed within the housing 127 of the IMD 126. Signal generator 84 includes circuitry, such as capacitors, charge pumps, regulators, current mirrors, and switches, configured to generate and deliver electrical signals to heart 122. For example, signal generator 84 may deliver pacing stimulation in the form of electrical pulses via the electrodes 124A-C. Signal generator 84 may include switches, and processor 80 may use the switches to select which of the available electrodes 124 are used to deliver therapy signals. The switches may include a switch array, switch matrix, multiplexer, or any other type of switching device suitable to selectively couple stimulation energy to selected electrodes.
Sensing module 86 monitors signals from at least one of electrodes 124A-C to monitor electrical activity of heart 122. Sensing module 86 may include electrical sensing circuitry such as filters and amplifiers, as well as an analog-to-digital converter. Sensing module 86 may also include switches to select which of the available electrodes are used to sense the heart activity, e.g., to sense a cardiac EGM, depending upon which electrode combination is used in the current sensing configuration. Sensing module 86 may include one or more detection channels, each of which may be coupled to a respective electrode combination and include an amplifier. The detection channels may be used to sense respective cardiac EGMs. Some detection channels may be configured detect cardiac events, such as, for example, R- or P-waves, or COI parameters, and provide indications of the occurrences of such events to the processor 80. In some examples, processor 80 detects cardiac events or determines other parameters discussed herein, e.g., COI parameters, based on a digitally converted EGM signal.
For generation and delivery of pacing pulses to the heart 122, processor 80 may utilize programmable counters to control the basic time intervals associated with VOO, OVO, DDD, VVI, DVI, VDD, AAI, DDI, DDDR, VVIR, DVIR, VDDR, AAIR, DDIR and other modes of single and dual chamber pacing. In the aforementioned pacing modes, “D” may indicate dual chamber, “V” may indicate a ventricle, “I” may indicate inhibited pacing (e.g., no pacing), and “A” may indicate an atrium. The first letter in the pacing mode may indicate the chamber that is paced, the second letter may indicate the chamber that is sensed, and the third letter may indicate the chamber in which the response to sensing is provided. The intervals may include atrial and ventricular pacing escape intervals, refractory periods during which sensed P-waves and R-waves are ineffective to restart timing of the escape intervals. Processor 80 may also define a blanking period, and provide signals to the sensing module 86 to blank one or more channels, e.g., amplifiers, for a period during and after delivery of electrical stimulation to heart 122. The durations of these intervals may be determined by processor 80 in response to stored data in memory 82.
As discussed above, IMD 126 may implement a number of techniques that improve its operation to, for example, verify satisfactory implantation in a way that may be automated and not require programmer 130. To that end, following attachment of a lead to the IMD 126, processor 80 may be configured to control IMD 126 to initiate a device test sequence according to qualification test parameters 83 stored in memory 82. In some examples, the device test sequence(s) are triggered automatically (without further input from the programmer 130 or other device external to the IMD 126) after the one or more leads are connected to the IMD. In the device test sequence according to some examples, processor 80 causes IMD 126 to conduct, in series or in parallel, the following qualification tests:
(1) detecting an impedance for at least one electrical path that includes the at least one electrode to determine a connection status of the IMD to the at least one electrode and, in some examples, the connection of the electrode to the patient; and
(2) comparing EGM amplitudes of, for example, R-waves, over an EGM test period against a predetermined threshold.
In some examples, IMD 126 further performs a qualification test (3), which includes determining a pacing capture threshold (PCT) for the IMD. Processor 80 may determine whether a PCT threshold is adequate, e.g., below a threshold. In some examples, the IMD 126 detects a signal indicative of capture during the PCT test and/or a clinician monitors the surface ECG of the patient to determine electrical activity of heart associated with pacing capture.
In some examples, the signal generator 84 paces the heart of the patient prior to, during, and/or after performing any of the qualification tests (1)-(3). In some examples, the pacing is in VOO mode (asynchronous ventricular pacing), and in some cases the pacing is in a VVI mode (ventricular demand pacing), but any form of ventricular or atrial pacing may be used. In some examples, IMD 126 operates in OVO mode (no chambers of the heart paced, ventricular sensing only).
Once one or more of the qualification tests (1)-(3) are completed in a passing range, in some examples IMD 126 generates an output signal indicating that the qualification tests are complete. In some examples, IMD 126 generates no output signal, but a clinician may observe on a surface ECG that pacing capture threshold (PCT) in qualification test (3) has been successfully performed by the IMD, e.g., based on observing an ECG signal reflecting successful capture of heart by the pacing delivered by IMD 126. Based on knowledge that successful capture completes the test sequence, the clinician may determine qualification tests have been successfully completed by IMD 126.
In qualification test (1), sensing module 86 and/or processor 80 are capable of collecting, measuring, and/or calculating impedance data according to impedance parameters 81 stored in memory 82 for any of a variety of electrical paths that include two or more of the electrodes 124A-C. Sensing module 86 may include an impedance measurement module 92 with circuitry configured to measure electrical parameter values during delivery of an electrical signal between at least two of the electrodes. Processor 80 may determine impedance values based on parameter values measured by the impedance measurement module 92, and store the measured impedance values in the memory 82.
In some examples, processor 80 may perform an impedance measurement by controlling delivery, from the signal generator 84, of a voltage pulse or other voltage-controlled waveform between selected first and second electrodes 124. The impedance measurement module 92 may measure a resulting current, and the processor 80 may calculate a resistance based upon the voltage amplitude of the pulse and the measured amplitude of the resulting current. In other examples, the processor 80 may perform an impedance measurement by controlling delivery, from the signal generator 84, of a current pulse or other current-controlled waveform between first and second electrodes, the measurement module 92 may measure a resulting voltage, and the processor 80 may calculate a resistance based upon the current amplitude of the pulse and the measured amplitude of the resulting voltage. The measurement module 92 may include circuitry for measuring amplitudes of resulting currents or voltages, such as sample and hold circuitry.
In these examples, signal generator 84 delivers signals that do not necessarily deliver stimulation therapy to the heart 122, due to, for example, the amplitudes of such signals and/or the timing of delivery of such signals. For example, these signals may include sub-threshold amplitude signals that may not stimulate the heart 122. In some cases, these signals may be delivered during a refractory period, in which case they also may not stimulate the heart 122. IMD 126 may use defined or predetermined pulse amplitudes, widths, frequencies, or electrode polarities for the pulses delivered for these various impedance measurements.
In certain cases, IMD 126 may measure impedance values that include both a resistive and a reactive (i.e., phase) component. In such cases, IMD 126 may measure impedance during delivery of a sinusoidal or other time varying signal by signal generator 84, for example. Thus, as used herein, the term “impedance” is used in a broad sense to indicate any collected, measured, and/or calculated value that may include one or both of resistive and reactive components.
Processor 80 may control a plurality of measurements of the impedance of any one or more electrical paths including combinations of electrodes 124A-C according to the impedance parameters 81 stored therein. In some examples, the processor 80 determines that the qualification test (1) is a pass when processor 80 determines that the impedance measurement module 92 detects an impedance threshold stored in the memory 82. In some examples, an impedance measurement of about 300Ω to about 2000Ω, or about 300Ω to about 1000Ω, is sufficient to provide a pass for qualification test (1).
In some examples, before and during IMD 126 performing the qualification test (1), signal generator 84 paces the heart in VOO mode (ventricular pacing, no sensing). For example, signal generator 84 paces the heart at about 80 beats per minute (bpm). In some examples, signal generator 84 and sensing module 86 may be used to pace the heart in VVI mode (sensed ventricular pacing) prior to the IMD performing the qualification test (1). For example, signal generator 84 may pace the heart at about 60 bpm in response to absence of detection of signals (e.g., detection of the absence of intrinsic R-waves) by sensing module 86. In some examples, the heart may be paced in VOO or VVI mode in parallel with the IMD performing the impedance measurements in qualification test (1).
Processor 80 may control signal generator 84 to deliver the pacing pulses during or after impedance measurement according to the qualification test parameters 83 stored in the memory 82. For example, processor 80 may control the timing or amplitude of test pulses based on the qualification test parameters 83 which, in some examples, can specify a period of time, e.g., a window, subsequent a pacing pulse or detected cardiac event, which may be an R-wave or a P-wave, or other EGM measurement, noise, an asystolic EGM signal, or the like, in which one or more impedance measurement pulses may be delivered. In some examples, the duration of the period may be selected as appropriate to determine the most accurate impedance values. Furthermore, by controlling the timing of impedance measurement pulses in this manner, IMD 126 may avoid interference with the accuracy of impedance measurements by intrinsic cardiac signals. Processor 80 may compare the impedances measured from each of the test pulses to an impedance threshold, and evaluate the connection and integrity of lead 112 based on the comparison. In some examples, processor 80 may also switch from a current sensing configuration to an alternative sensing or therapy configuration in response to determining a lead related condition or other integrity issue with a configuration.
In some examples, IMD 126 repeatedly performs the qualification test (1) until the processor 80 determines a passing impedance measurement over a predetermined time period such as, for example, 2 minutes, 5 minutes, 15 minutes, 30 minutes, 45 minutes or 1 hour. If the measured impedance during the predetermined time period is not within a predetermined passing range, qualification test (1) is determined by the processor 80 to be a failure, and the result is optionally stored in the memory 82. In some examples, the predetermined passing range is about 300Ω to about 2000Ω, or about 300Ω to about 1000Ω, but the passing range may be set at any appropriate level. If the measured impedance in qualification test (1) is within the passing range, the qualification test (1) is determined by the processor 80 to be a pass, and the result may optionally be stored in the memory 82. If the qualification test (1) is determined to be a pass, in some examples the processor 80 may cause the signal generator 84 and the sensing module 86 to initiate pacing of the heart in, for example, VVI mode, prior to initiation of qualification tests (2) or (2)-(3). For example, in some cases, the pacing is applied by the IMD to the heart at 60 bpm at a pacing output of about 5 V.
In some examples, the following completion of qualification test (1), processor 80 controls IMD 126 to perform qualification test (2). In qualification test (2), processor 80 may detect aspects of EGM signals sensed by sensing module 86 such as, for example, R-waves, P-waves, and COI parameters, according to test criteria 85 stored within the memory 82. In some examples, the EGM test criteria 85 may include one or more R-wave or P-wave amplitude thresholds, to which the processor 80 may compare amplitudes of sensed R-waves and P-waves. As an example, the suitable EGM threshold may be satisfied by measurable R-waves having an amplitude of at least about 5 mV. If the EGM threshold(s) are satisfied, the qualification test (2) is completed and the processor 80 initiates the optional qualification test (3). If the heart rate is too fast, e.g., whether or not the EGM threshold is determined to be a pass, the processor may repeat one or both of qualification tests (1) and (2), in some examples.
In some examples, if processor 80 and sensing module 84 are unable to detect a threshold number of R-waves or other EGM components satisfying the threshold amplitude, processor 80 may lower the pacing rate, e.g., lengthen the escape interval, to allow more intrinsic conduction. For example, processor 80 may decrement the pacing rate, e.g., by steps or otherwise, to minimum rate, e.g., 40 beats per minute (bpm). If the EGM sensing still does not pass the test, processor may change the EGM sensing parameters, e.g., amplitude threshold or electrodes 124 used for sensing.
In some examples, processor 80 may perform COI tests according to COI test parameters 85 in the memory 82, following the completion of the EGM qualification test (2), or in parallel with the EGM qualification test (2). In some examples, sensing module 86 may sense the heart in, for example, OVO mode, prior to initiation of the COI test parameters stored in the memory 82. Suitable COI parameters 85 in the memory 82 include, but are not limited to, determination of: the maximum amplitude of the ST segment in the EGM of the patient, amplitude of the ST segment 80 milliseconds (ms) from the segment's beginning, the area under the wave curve (from R-wave start to the end of the ST segment), the area under the ST segment, amplitude at a start of ST segment, median and quartile amplitudes of the first 200 ms following ST segment, amplitude of the R wave, duration of the ST segment, duration of the signal (QT), ratio of R-wave amplitude to maximum amplitude of ST segment, ratio of R-wave amplitude to amplitude of ST segment 80 ms from start, and combinations thereof.
In some examples, processor 80 may determine the values of COI parameters based on an analysis of a digitized version of the EGM signal. For example, processor 80 may perform a deconvolution operation of the time-series of EGM samples to recover lower frequency COI content, e.g., emphasize features in the EGM indicative of COI. In some examples, the other EGM signals such as R-wave or P-wave amplitude may be evaluated over the same time period that the COI parameters are determined. If insufficient COI is detected, or if insufficient EGM amplitudes are detected, the qualification test (2) may be terminated by the processor 80.
If processor 80 determines that IMD 126 passes qualification test (2), processor 80 optionally initiates qualification test (3) to evaluate the PCT of IMD 126 according to the PCT/VCM (ventricular capture management) parameters 87 in the memory 82. In the PCT qualification test, VCM module 89, sensing module 86, and signal generator 84 operate according to PCT parameters stored in the memory 82 to evaluate the energy required to cause depolarization and contraction of the heart tissue of the patient, and compares the required energy to a PCT threshold. For example, in some embodiments, the PCT threshold may be evaluated by VCM module 89 to automatically monitor pacing thresholds at periodic intervals. Once the pacing threshold is determined, in some examples VCM module 89 determines a target pacing output based on a predetermined safety margin and a predetermined minimum EGM amplitude.
In some examples, processor 80 may run abbreviated VCM tests in which the PCT capture threshold is required to be less than about 2.5 V. In some examples, the processor 80 initiates the signal generator 84 to pace the heart in VVI mode for a predetermined time period (for example, 30 seconds to 60 seconds) to evaluate PCT capture threshold. In some examples, the heart is paced in VVI mode at about 90 bpm to determine the PCT capture threshold. Such a pacing rate is likely faster than the intrinsic heart rate of the patient so that intrinsic heart beats will not interfere with pacing capture threshold testing.
If the PCT capture threshold is not achieved, the processor 80 indicates that qualification test (3) was not successful, and the result may optionally be stored in the memory 82. If the PCT capture threshold is achieved and qualification test (3) is determined to be a pass, in some examples processor 80 may generate a confirmation signal, and a result is optionally stored in the memory 82. Suitable indications include, for example, energizing a LED, an audible alert, or sending a confirmation signal to an optional programmer 130. In some examples, processor 80 provides no indication of the status of the qualification test (3), and pacing capture may be evaluated by a clinician as pacing at a fixed rate visible to the clinician on a surface ECG monitor.
In some examples, if qualification test (3) is determined to be a pass, IMD 126 switches back to pacing in, for example, OVO mode, for a predetermined period of time (for example, about 6 seconds to about 10 seconds) to allow intrinsic conduction so that sensing module 86 may measure COI parameters. The COI parameters may then be compared to previously measured COI values stored in memory 82, and if a COI percent change threshold is met, the processor 80 provides an indication that the qualification test (3) and the COI parameters were successful. If the COI percent change threshold fails, the processor 80 instructs the signal generator 84 and the sensing module 86 to switch to pacing in, for example, VVI mode, for a predetermined period of time such as, for example, about 60 seconds.
After a selected pacing time of, for example, about 60 seconds, processor 80 may instruct the signal generator 84 and the sensing module 86 to return to OVO mode and the COI parameters are again evaluated and compared the COI values previously stored in memory 82. For example, the COI values may be compared to stored COI values previously stored in memory 82 from COI measurements completed by IMD 126 minutes to 5 minutes earlier. If the COI percent change threshold is met, processor 80 generates an output indicating that the qualification test (3) and the COI determination were a pass. Otherwise, the processor 80 may output an indication that the COI parameters were not satisfied.
The various components of the IMD 126 are coupled to a power source 90, which may include a rechargeable or non-rechargeable battery. A non-rechargeable battery may be capable of holding a charge for several years, while a rechargeable battery may be inductively charged from an external device, e.g., on a daily or weekly basis.
Prior to or at the same time the device test sequence initiates, the signal generator 84 (
If qualification test (1) is a pass (YES of 204), processor 80 triggers the signal generator 84 and the sensing module 86 to perform pacing of the ventricle of the heart of the patient in VVI mode at a rate of 60 bpm and with an R-wave sensitivity of 5 mV (206). Processor 80 then initiates the qualification test (2) by applying R-wave test criteria 85 stored in the memory 82 (208). If the measured intrinsic heart rate exceeds a threshold (210), processor 80 may return to the VOO pacing (202) and re-runs qualification test (1) (204). If the R-wave criteria are not met due to too few measured R-waves (212), processor 80 determines whether the pacing rate has already been decremented to a minimum value, e.g., 40 bpm (214). If so (YES of 214), processor 80 may return IMD 126 to qualification test (1) (202,204) without providing feedback of a successful test. If the pacing rate has not yet been decremented to the minimum value (NO of 214), processor 80 decrements the pacing rate (218) and again attempts to detect and measure R-waves until the R-wave test criteria 85 are satisfied (208). If excessive processor 80 determines that an amount of noise detected in the EGM signal detected by sensing module 86 during qualification test (2) (220), the processor may return to the qualification test (1) (202, 204).
If the measured EGM amplitudes satisfy the EGM test criteria 85 (222), the qualification test (2) is deemed a pass. Processor 80 may delay for 30 seconds (224), and then configured the sensing module 86 and the signal generator 84 to apply pacing to the heart in VVI mode at 90 bpm and 2.5 V for 30 seconds (226). A clinician may then observe a surface ECG monitor to confirm proper pacing and device capture. The operation of
According to the device test sequence, processor 80 controls signal generator 84 (
If qualification test (1) is a pass (YES of 304), processor 80 triggers signal generator 84 and the sensing module 86 to pace the heart of the patient in VVI mode at a rate of 60 bpm (306). Processor 80 may then initiate the qualification test (2) by applying R-wave test interval criteria 85 stored in the memory 82 to the EGM sensing by sensing module 86 (308). If the measured intrinsic heart rate is determined to be too high, e.g., by exceeding a heart rate threshold (310), processor 80 returns to the VOO pacing (302), re-runs qualification test (1) (304).
If the R-wave criteria are not met due to too few measured R-waves (312), processor 80 determines whether the pacing rate has already been decremented to a minimum value, e.g., 40 bpm (314). If so (YES of 314), processor 80 may return IMD 126 to qualification test (1) (302, 304) without confirmation to the clinician or with a signal of non-confirmation (317). If the pacing rate has not yet been decremented to the minimum value (NO of 314), processor 80 may decrement the pacing rate (318) and sensing module 86 may again attempt to detect and measure R-waves until the EGM test criteria 85 are satisfied (308). If sensing module 86 detects an amount of noise in the sensed EGM greater than a threshold (320), processor 80 may return IMD 126 to the qualification test (1) (302, 304) without confirmation to the clinician or with a non-confirmation signal to the clinician (317).
If the R-wave interval criteria 85 are satisfied (YES of 308), processor 80 applies an R-wave amplitude test from the EGM test criteria 85 (322), and determines whether the R-waves meet the criteria, e.g., whether a sufficient number of R-waves were sensed when sensing module 86 applies a threshold of 5 mV (324). If the sensed R-waves meet the criteria (YES of 324), the qualification test (2) is deemed a pass and processor 80 may proceed qualification test (3) (326). If the sensed R-waves do not meet the 5 mV criteria (NO of 324), processor 80 may return IMD 126 to the qualification test (1) (302, 304) without confirmation to the clinician (317).
In qualification test (3), processor 80 may initially perform a rate and stability check (326). If the check is passed (YES of 326), processor 80 may control VCM module 89 to perform an abbreviated VCM test to determine whether capture occurs at or below 2.5V (330). In capture is confirmed (YES of 332), processor 80 may control IMD 126 to provide a confirmation signal (334), which may include pacing at VVI 90 for 30 seconds (336). If the VVI pacing protocol is successful as observed on a surface ECG, the qualification test (3) is deemed a pass, and the implant of the IMD is deemed to be successful. If the PCT is outside the target range at 2.5 V (NO of 332) or the rate and stability check is not passed (NO of 326), the VCM module re-initiates the VCM test, or after a predetermined number of attempts processor 30 controls IMD to provide a non-confirmation signal or returns IMD 126 to the qualification test (1) (302, 304) without confirmation to the clinician (317).
According to the device test sequence, processor 80 controls signal generator 84 and sensing module 86 (
If qualification test (1) is a pass (YES of 404), processor controls IMD 126 to return to the VVI mode. For intrinsic beats that are sensed during pacing in the VVI mode, processor 80 may control sensing module 86 to perform qualification test (2) by applying an interval measurement in the EGM test criteria 85 stored in the memory 82 for sensing intrinsic beats (408). If the measured heart rate is too high, e.g., above a threshold rate, processor 80 returns continues pacing in the VVI mode (410). If the R-wave criteria are not met due to too few intrinsic R-waves (412), processor 80 determines whether the pacing rate is at a minimum value, e.g., 40 bpm (414). If the pacing rate is not at the minimum (NO of 414), processor 80 may decrement the pacing rate (418) and continue VVI pacing and monitoring for intrinsic R-waves. If the pacing rate has already been decremented to 40 bpm (YES 414), processor 80 may provide a non-confirmation signal in step 417 that qualification test (2) is not a pass, and re-initiate qualification tests (1 and 2) (402, 404, and 408).
If processor 80 determines that an amount of noise in the EGM exceeds a threshold (420), the processor may control impedance measurement module 92 to measure impedance and determine whether the measurement is valid (422). If the measured lead impedance is valid (YES of 422), processor 80 may issue a non-confirmation signal 417 and re-initiate qualification tests (1 and 2) (402, 404, and 408). If the measured impedance is not valid (NO of 422), processor 80 may control IMD 126 to switch to VOO pacing, e.g., at a rate of 80 bpm (424), and determine whether the measured impedances meet impedance criteria 81 (404).
If the sensed R-waves satisfy interval criteria of test criteria 85, processor 80 applies an R-wave amplitude test from the EGM test criteria 85 (428). Processor 80 determines whether one or more R-wave amplitudes are greater than a threshold, e.g., 5 mV, and the impedance check from qualification test (1) is a pass (430). If criteria of qualification tests (1) and (2) are met (YES of 430), processor 80 proceeds to perform a capture management rate and stability check (432). If the measured R-wave amplitude(s) do not meet the 5 mV threshold (NO of 430 and 434), processor 80 causes IMD 126 to return the non-qualification signal (417), and may return to VVI pacing at 60 bpm (402). If the measured R-wave amplitude(s) do meet the 5 mV threshold, but the impedance check was not a pass (NO of 430 and YES 434), processor 80 may control IMD 126 to transition to VOO pacing at 80 bpm and control impedance measurement module 92 to measure impedances (436). If the impedance check is not a pass (NO of 437), processor 80 returns the non-confirmation signal (417), and may return to VVI pacing at 60 bpm (402). If the impedance check is a pass (YES of 437), processor 80 proceeds to perform a capture management rate and stability check (432).
If the rate and stability check is passed (YES of 432), processor 80 may control VCM module 89 to perform an abbreviated VCM test to determine whether capture occurs at or below 2.5V (440). Processor 80 sets ventricular pacing output to 2.5V and the PCT is evaluated by the VCM module 89. In capture is confirmed (YES of 442), processor 80 may control IMD 126 to provide a confirmation signal (444), which may include pacing at VVI 90 for 30 seconds (446). If the VVI pacing protocol is successful as observed on a surface ECG, the qualification test (3) is deemed a pass, and the implant of the IMD is deemed to be successful. If capture is not observed/detected at 2.5 V (NO of 442) or the rate and stability check is not passed (NO of 432), the VCM module re-initiates the VCM test, or after a predetermined number of attempts processor 80 controls IMD to provide a non-confirmation signal (417) or returns IMD 126 to the qualification tests (1 and 2) and VVI pacing (402) with a signal of confirmation to the clinician (417).
According to qualification test (2), processor 80 may control IMD 126 to enter an OVO mode and sensing module 86 to sense intrinsic R-wave amplitudes and COI parameters (504,506). As noted above, COI parameters 85 can include the maximum amplitude of the ST segment, the amplitude of the ST segment 80 ms from the segment's beginning, the area under the wave curve (from R-wave start to the end of the ST segment), the area under the ST segment, amplitude at a start of ST segment, median and quartile amplitudes of the first 200 ms following ST segment, amplitude of the R wave, duration of the ST segment, duration of the signal (QT), ratio of R-wave amplitude to maximum amplitude of ST segment, ratio of R-wave amplitude to amplitude of ST segment 80 ms from start, and combinations thereof. If insufficient COI is detected after an evaluation period of about 6 seconds, processor 80 outputs that the implant failed (508). If an insufficient R-wave amplitude is detected, e.g., after an evaluation period of 6 seconds, processor 80 outputs that the implant failed (510).
Otherwise, processor 80 controls IMD 126 to switch to pacing in VVI mode for 60 seconds to evaluate pacing capture threshold (PCT) in qualification test (3) (512). If there is not proper capture as measured by the VCM module 89, processor outputs that implant has failed (508). If there is proper capture, processor 80 controls IMD 126 to switch back to OVO mode for a period of 6 seconds to calculate COI parameters (514). The COI parameter values are compared to the values from a time period before current values, such as 1 minute, 5 minutes, or 10 minutes. If the COI percent change threshold is met, processor 80 outputs that the implant passed (516). If the COI percent change threshold fails, processor 80 controls IMD 126 to pace in VVI mode for 60 seconds (518).
After 60 seconds of pacing, processor 80 returns IMD 126 to OVO mode to calculate COI parameters again (520). The parameters are compared to the initial values from 2 minutes before. If the COI percent change threshold is met, processor 80 outputs that the implant passed (516). Otherwise, processor 80 outputs that the implant failed (508).
If the qualification test (1) is determined to be a pass (YES of 602), processor 80 may switch IMD 126 to operation in the OVO mode, and the sensing module 86 may sense intrinsic R-wave amplitudes and COI parameters for qualification test (2) (604). As noted above, these COI parameters 85 can include determining any or all of the following: the maximum amplitude of the ST segment, the amplitude of the ST segment 80 ms from the segment's beginning, the area under the wave curve (from R-wave start to the end of the ST segment), the area under the ST segment, amplitude at a start of ST segment, median and quartile amplitudes of the first 200 ms following ST segment, amplitude of the R wave, duration of the ST segment, duration of the signal (QT), ratio of R-wave amplitude to maximum amplitude of ST segment, ratio of R-wave amplitude to amplitude of ST segment 80 ms from start, and combinations thereof.
If R-wave amplitude sensing is determined to be insufficient (NO of 605), qualification test (2) is determined to be a failure. If R-wave amplitude sensing is determined to be sufficient (YES of 605), processor 80 switches IMD 126 to pacing in VVI mode for a period of time such as 30 or 60 seconds (606), and proceeds to perform the impedance check of qualification test (1) (608). To avoid intrinsic cardiac interference, in some examples VOO pacing may performed instead of VVI pacing for this impedance measurement. If the impedance check of qualification test (1) is determined to be out of a passing range (NO of 608), processor 80 assumes that a lead is being repositioned or reconnected to the IMD and waits (603) prior to performing another impedance check (602).
If the impedance is within a passing range (YES of 608), processor 80 again implements VVI pacing for 30 seconds (610) and re-checks impedance (612). If the impedance is in a passing range (YES of 612), processor 80 switches to OVO mode for a period of about 6 seconds, and calculates any or all of the COI parameters discussed above with respect to step 604 (614).
Processor 80 controls IMD 126 to initiate overdrive pacing in VVI mode for 30 seconds to evaluate device capture at 1.5 V for PCT qualification test (3) (616). If there is not proper capture at 1.5V as measured by the VCM module 89 (NO of 618), processor 80 outputs that the implant failed (619). If there is proper capture (YES of 618), processor 80 again controls performance of impedance measurements for qualification test (1) (620). If the impedance is within a predetermined passing range (YES of 620), processor 80 controls IMD 126 to pace the heart in VVI mode for 30 seconds (622), and then again checks impedance (624).
If the impedance remains in the passing range (YES of 624), processor 80 switches IMD 126 back to OVO mode for a period of 6 seconds to calculate COI parameters (626). Processor 80 compares the COI parameters to the previously measured COI values from steps 604 and 614 (628). If the COI percent change threshold is met (YES of 628), processor outputs an indication that the implant passed (630). If the COI percent change threshold is not met (NO of 628), processor 80 may indicate that the IMD implantation failed (629).
It should be noted that the therapy system 100 may not be limited to treatment of a human patient. In alternative examples, the therapy system 100 may be implemented in non-human patients, e.g., primates, canines, equines, pigs, and felines. These other animals may undergo clinical or research therapies that my benefit from the subject matter of this disclosure.
As shown in
Electrodes 732 and 740 are carried on the housing created by case 730 and cap 738. In this manner, electrodes 732 and 740 may be considered leadless electrodes, and IMD 700 may be considered a leadless IMD, e.g., a leadless pacemaker or leadless pacing device. In the example of
Electrode 740 may be used as a cathode and electrode 732 may be used as an anode, or vice versa, for delivering cardiac pacing such as bradycardia pacing, CRT, ATP, or post-shock pacing. However, electrodes 732 and 740 may be used in any stimulation configuration. In addition, electrodes 732 and 740 may be used to detect intrinsic electrical signals, e.g., from cardiac muscle.
Fixation mechanisms 742 may attach IMD 700 to tissue, e.g., cardiac tissue. Fixation mechanisms 742 may be active fixation tines, screws, clamps, adhesive members, or any other mechanisms for attaching a device to tissue. As shown in the example of
IMD 700, e.g., processor 80 of IMD 700, may be configured to detect placement of the IMD into a patient and, in response to placement of the IMD into the patient, to initiate a device test sequence, comprising any of the a plurality of qualification tests disclosed herein, over an evaluation period. Processor 80 may be configured to detect positioning of IMD 700 within patient based on a change in impedance measured by impedance measurement circuitry 92 via electrodes 732 and 740 when the electrodes are exposed to blood and/or come into contact with tissue. For the test sequence, processor 80 may control IMD 700 to perform qualification tests including measurement of impedance, comparison of EGM amplitudes to a threshold, evaluation of pacing capture, determining COI parameters, or any one or more of the tests described herein.
The techniques described in this disclosure, including those attributed to the IMDs 126 and 700, the programmer 130, or various constituent components, may be implemented, at least in part, in hardware, software, firmware or any combination thereof. For example, various aspects of the techniques may be implemented within one or more processors, including one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or any other equivalent integrated or discrete logic circuitry, as well as any combinations of such components, embodied in programmers, such as physician or patient programmers, stimulators, image processing devices or other devices. The term “processor” or “processing circuitry” may generally refer to any of the foregoing logic circuitry, alone or in combination with other logic circuitry, or any other equivalent circuitry.
Such hardware, software, firmware may be implemented within the same device or within separate devices to support the various operations and functions described in this disclosure. In addition, any of the described units, modules or components may be implemented together or separately as discrete but interoperable logic devices. Depiction of different features as modules or units is intended to highlight different functional aspects and does not necessarily imply that such modules or units must be realized by separate hardware or software components. Rather, functionality associated with one or more modules or units may be performed by separate hardware or software components, or integrated within common or separate hardware or software components.
When implemented in software, the functionality ascribed to the systems, devices and techniques described in this disclosure may be embodied as instructions on a computer-readable medium such as random access memory (RAM), read-only memory (ROM), non-volatile random access memory (NVRAM), electrically erasable programmable read-only memory (EEPROM), FLASH memory, magnetic data storage media, optical data storage media, or the like. The instructions may be executed to support one or more aspects of the functionality described in this disclosure.
Various examples have been described. These and other examples are within the scope of the following claims.
Embodiment A. A method comprising:
detecting, by an implantable medical device (IMD), attachment to the IMD of at least one implantable medical lead, wherein the at least one implantable medical lead comprises at least one electrode; and
triggering by the IMD, based on the detecting of the attachment to the IMD of the at least one medical lead, a device test sequence in which the IMD performs the following qualification tests over an evaluation period:
(1) detecting an impedance for at least one electrical path that includes the at least one electrode to determine a connection status of the IMD to the at least one electrode; and
(2) comparing EGM (electrogram) amplitudes of the patient over an EGM test period against a predetermined threshold.
Embodiment B. The method of Embodiment A, wherein the device test sequence further comprises a qualification test (3), monitoring pacing capture threshold (PCT) of the IMD.
Embodiment C. The method of Embodiments A to B, wherein qualification tests (1)-(2) are performed sequentially.
Embodiment D. The method of any of Embodiments A to C, wherein qualification tests (1)-(2) are performed in parallel.
Embodiment E. The method of any of Embodiments A to D, wherein qualification tests (2)-(3) are performed following qualification test (1).
Embodiment F. The method of any of Embodiments B to E, wherein the IMD measures current of injury (COI) parameters in an EGM of the patient prior to, during, or after, qualification test (3).
Embodiment G. The method of any of Embodiments A to F, wherein the IMD measures current of injury (COI) parameters following qualification test (1).
Embodiment H. The method of any of Embodiments A to G, wherein the IMD measures current of injury (COI) parameters following qualification test (1), and in parallel with qualification test (2).
Embodiment I. The method of any of Embodiments B to H, wherein if the IMD passes any of the qualification tests (1)-(3) over the evaluation period, the IMD generates a confirmation signal.
Embodiment J. The method of any of Embodiments A to I, wherein the IMD automatically initiates the device test sequence, without input from an external programmer, when the at least one implantable lead is connected to the IMD.
Embodiment K. The method of any of Embodiments A to J, wherein an impedance passing range for the qualification test (1) is about 300Ω to about 2000Ω.
Embodiment L. The method of any of Embodiments A to K, wherein the evaluation period is about 2 minutes to about 1 hour following attachment of the at least one lead to the IMD.
Embodiment M. The method of any of Embodiments A to L, wherein the evaluation period is about 5 minutes to about 30 minutes after attachment of the at least one lead to the IMD.
Embodiment N. The method of any of Embodiments A to M, wherein the IMD paces the heart of the patient in a single chamber asynchronous mode prior to or during performance of the device test sequence.
Embodiment O. The method of Embodiment N, wherein the IMD paces the heart at a fixed rate of at least 80 pulses per minute.
Embodiment P. The method of any of Embodiments A to O, wherein the IMD performs single chamber demand pacing on the heart of the patient prior to or during performance of the device test sequence.
Embodiment Q. The method of Embodiment P, wherein the demand pacing is delivered at a rate of about 60 pulses per minute.
Embodiment R. The method of any of Embodiments A to Q, further comprising generating, by the IMD, an alert confirming termination of the device test sequence.
Embodiment S. The method of any of Embodiments A to R, wherein if the impedance detected by the IMD in qualification test (1) is within an impedance passing range, the IMD paces the heart of the patient in a single chamber demand mode.
Embodiment T. The method of Embodiment S, wherein the IMD paces the heart at about 60 bpm in VVI mode at a pacing output of about 5 V.
Embodiment U. The method of Embodiment S, wherein the IMD paces the heart at 60 bpm in AAI mode at a pacing output of about 1 V.
Embodiment V. The method of any of Embodiments A to U, wherein the qualification test (2) runs over an EGM test period of at least 30 seconds.
Embodiment W. The method of any of Embodiments A to V, wherein if the IMD measures an R-wave amplitude, or an average or a median R-wave amplitude, of at least about 5 mV over the EGM test period, the IMD terminates qualification test (2).
Embodiment X. The method of any of Embodiments A to W, wherein if the IMD measures a P-wave amplitude, or an average or a median P-wave amplitude, of at least about 1 mV over the EGM test period, the IMD terminates qualification test (2).
Embodiment Y. The method of any of Embodiments A to X, wherein if the IMD measures a R-wave amplitude, or an average or a median R-wave amplitude, of less than about 5 mV over the EGM test period, the IMD re-starts qualification test (2).
Embodiment Z. The method of any of Embodiments A to Y, wherein if the IMD measures a P-wave amplitude, or an average or a median P-wave amplitude, of at least about 1 mV over the EGM test period, the IMD re-starts qualification test (2).
Embodiment AA. The method of any of Embodiments A to Z, wherein if the IMD determined no sensed cardiac events in a predetermined time period, the IMD terminates qualification test (2).
Embodiment BB. The method of any of Embodiments A to AA, wherein the IMD performs qualification test (2) on a predetermined number of cardiac sensed events having the lowest measured amplitudes.
Embodiment CC. The method of any of Embodiments A to BB, wherein following termination of qualification test (2) is a pass, the IMD paces a heart of the patient in single chamber demand mode.
Embodiment DD. The method of Embodiment CC, wherein the IMD paces the heart at 90 bpm in single chamber demand mode for about 30 seconds.
Embodiment EE. The method of Embodiment DD, wherein the IMD paces the heart in VVI mode at a pacing output of about 2.5 V.
Embodiment FF. The method of Embodiment DD, wherein the IMD paces the heart in AAI mode at a pacing output of about 1 V.
Embodiment GG. The method of any of Embodiments B to FF, wherein qualification test (3) comprises pacing, by the IMD, of a heart of the patient in single chamber demand mode.
Embodiment HH. The method of any of Embodiments A to GG, wherein the IMD paces the heart in VVI mode at 2.5V for about 30 seconds to about 60 seconds.
Embodiment II. The method of any of Embodiments A to HH, wherein the IMD paces the heart in AAI mode at 1 V for about 30 seconds to about 60 seconds.
Embodiment JJ. The method of any of Embodiments E to II, wherein the IMD measures the current of injury (COI) parameters in an electrogram of the patient by performing at least one of the following steps: determining a maximum amplitude of an ST segment, determining an amplitude of the ST segment 80 milliseconds from a beginning of the segment, determining an area under a wave curve from an R-wave start to the end of the ST segment, and determining an area under the ST segment.
Embodiment KK. The method of Embodiment JJ, wherein the COI parameters are determined in OVO or VVI mode.
Embodiment LL. The method of Embodiments JJ to KK, wherein the COI parameters are determined in OVO mode or VVI mode after completion of the qualification test (3), and wherein the IMD determines the COI parameters over a predetermined interval.
Embodiment MM. The method of Embodiment LL, wherein the predetermined interval is about 6 seconds.
Embodiment NN. A method comprising:
detecting, by an implantable medical device (IMD), attachment to the IMD of at least one implantable medical lead, wherein the at least one implantable medical lead comprises at least one electrode;
triggering by the IMD, based on the detecting of the attachment of the at least one implantable medical lead, a device test sequence in which the IMD performs the following steps over an evaluation period:
(1) delivering a pacing stimulus to a heart of the patient in a single chamber asynchronous mode;
(2) prior to or during step (1), periodically detecting an impedance for at least one electrical path that includes the at least one electrode, and determining, based on whether the impedance detected by the IMD is within a passing range, a connection status of the IMD to the at least one electrode;
(3) pacing the heart of the patient in demand mode;
(4) comparing, over an EGM test period, cardiac sensed event amplitudes in an electrogram of the heart of the patient over an EGM test period against a predetermined threshold; and
(5) pacing the heart of the patient in demand mode to determine a pacing capture threshold (PCT).
Embodiment 00. The method of Embodiment NN, wherein following completion of the steps (1)-(5) over an evaluation period, generating by the IMD a confirmation signal.
Embodiment PP. The method of Embodiments NN to OO, comprising pacing by the IMD the heart of the patient in single chamber asynchronous mode at a fixed rate of at least 80 pulses per minute prior to or after performing the device test sequence.
Embodiment QQ. The method of any of Embodiments NN to PP, wherein in step (3) the IMD paces the heart of the patient at 60 bpm in VVI mode at a pacing output of about 5 V.
Embodiment RR. The method of any of Embodiments NN to QQ, wherein in step (3) the IMD paces the heart of the patient at 60 bpm in AAI mode at a pacing output of about 1 V.
Embodiment SS. The method of any of Embodiments NN to RR, wherein in step (5) the IMD paces the heart of the patient at 90 bpm in VVI mode for 30 seconds at a pacing output of about 2.5 V to determine a device capture.
Embodiment TT. The method of an of Embodiments NN to SS, wherein in step (5) the IMD paces the heart of the patient at 90 bpm in AAI mode for 30 seconds at a pacing output of about 1 V to determine a device capture.
Embodiment UU. A method comprising:
detecting, by an implantable medical device (IMD), attachment to the IMD of at least one implantable medical lead, wherein the at least one implantable medical lead comprises at least one electrode;
triggering by the IMD, based on the attachment to the IMD of the at least one implantable medical lead, a device test sequence in which the IMD performs the following steps over an evaluation period:
(1) pacing a heart of the patient in single chamber demand mode;
(2) periodically detecting an impedance for at least one electrical path that includes the at least one electrode, and determining, based on whether the impedance detected by the IMD is within a predetermined range, a connection status of the IMD to the at least one electrode;
(3) comparing, over an EGM test period, cardiac sensed event amplitudes in an electrogram of the patient over an EGM test period against a predetermined threshold; and
(4) pacing the heart of the patient, for a predetermined time period, in single chamber demand mode to determine a pacing capture threshold (PCT).
Embodiment VV. The method of Embodiment UU, wherein steps (2) and (3) are performed in parallel.
Embodiment WW. The method of Embodiments UU to VV, wherein the IMD generates a confirmation signal when steps (1)-(4) are complete.
Embodiment XX. The method of any of Embodiments UU to WW, wherein the evaluation period is about 2 minutes to about 1 hour.
Embodiment YY. The method of any of Embodiments UU to XX, wherein if step (2) results in an impedance measurement outside a passing range of about 300Ω to about 2000Ω, the 1 MB paces the heart of the patient in single chamber asynchronous mode.
Embodiment ZZ. The method of any of Embodiments UU to YY, wherein if impedance detected by the IMD is outside the impedance passing range of about 300Ω to about 2000Ω, the 1 MB returns to step (1) and repeats step (2) until the IMD detects an impedance in the passing range.
Embodiment AAA. The method of any of Embodiments UU to ZZ, wherein IMD paces the heart of the patient at 60 bpm at a pacing output of about 2.5V in VVI mode in step (1).
Embodiment BBB. The method of any of Embodiments UU to AAA, wherein IMD paces the heart of the patient at 60 bpm at a pacing output of about 1V in AAI mode in step (1).
Embodiment CCC. The method of any of Embodiments UU to BBB, wherein the IMD performs step (3) over an EGM test period of at least 30 seconds.
Embodiment DDD. The method of Embodiment CCC, wherein if the R-wave amplitude measured by the IMD is at least about 5 mV over the EGM test period, the IMD terminates the EGM test sequence.
Embodiment EEE. The method of any of Embodiments UU to DDD, wherein if the R-wave amplitude measured by the IMD is less than about 5 mV over the EGM test period, the IMD re-starts the EGM test sequence.
Embodiment FFF. The method of Embodiment CCC, wherein if the P-wave amplitude measured by the IMD is at least about 1 mV over the EGM test period, the IMD terminates the EGM test sequence.
Embodiment GGG. The method of any of Embodiments UU to FFF, wherein if the P-wave amplitude measured by the IMD is less than about 1 mV over the EGM test period, the IMD re-starts the EGM test sequence.
Embodiment HHH. The method of any of Embodiments UU to GGG, wherein the IMD measures cardiac sensed events, and terminates the test sequence if the number of cardiac sensed events is less than a predetermined threshold.
Embodiment III. The method of any of Embodiments UU to HHH, wherein the IMD performs the EGM test sequence on a predetermined quantity of the measured cardiac sensed events with the lowest amplitudes.
Embodiment JJJ. The method of any of Embodiments UU to III, wherein the IMD paces the heart of the patient at 90 bpm at 2.5 V in VVI mode for 30 seconds in step (4) to determine capture of the device.
Embodiment KKK. The method of any of Embodiments UU to JJJ, wherein the IMD paces the heart of the patient at 90 bpm at 1 V in AAI mode for 30 seconds in step (4) to determine capture of the device.
Embodiment LLL. A method comprising:
detecting, by an implantable medical device (IMD), attachment to the IMD of at least one implantable medical lead, wherein the at least one implantable medical lead comprises at least one electrode;
triggering by the IMD, based on the detecting of the attachment of the at least one implantable medical lead a device test sequence in which the IMD performs the following steps over an evaluation period:
(1) delivering a pacing stimulus to a heart of the patient in single chamber asynchronous mode;
(2) periodically detecting an impedance for at least one electrical path that includes the at least one electrode, and determining, based on whether the impedance detected by the IMD is within a passing range, a connection status of the IMD to the at least one electrode;
(3) pacing the heart of the patient in single chamber demand mode;
(4) comparing, over an EGM test period, cardiac sensed event amplitudes in an electrogram of the patient over an EGM test period against a predetermined threshold; and
(5) pacing the heart of the patient in single chamber demand mode.
Embodiment MMM. The method of Embodiment LLL, wherein an impedance passing range for the device test sequence (2) is about 300Ω to about 2000Ω.
Embodiment NNN. The method of Embodiments LLL to MMM, wherein the evaluation period is about 15 minutes to about 1 hour.
Embodiment OOO. The method of Embodiments LLL to NNN, wherein the IMD paces the heart of the patient in a single chamber asynchronous mode prior to or during step (1) at a fixed rate of at least 80 pulses per minute.
Embodiment PPP. The method of any of Embodiments LLL to OOO, wherein the IMD paces the heart of the patient at 60 bpm at a pacing output of about 5 V in VVI mode in step (3).
Embodiment QQQ. The method of any of Embodiments LLL to PPP, wherein the IMD paces the heart of the patient at 60 bpm at a pacing output of about 1 V in AAI mode in step (3).
Embodiment RRR. The method of any of Embodiments LLL to QQQ, wherein the IMD runs step (4) over an EGM test period of about 5 seconds to about 30 seconds.
Embodiment SSS. The method of Embodiment RRR, wherein if a measured R-wave amplitude is at least about 5 mV over the EGM test period, the IMD terminates step (4).
Embodiment TTT. The method of Embodiment RRR, wherein if a measured R-wave amplitude is less than about 5 mV over the EGM test period, the IMD re-starts the EGM test sequence; or moves to step (5) and re-starts the EGM test sequence at a later time.
Embodiment UUU. The method of Embodiment RRR, wherein if a measured P-wave amplitude is at least about 1 mV over the EGM test period, the IMD terminates step (4).
Embodiment VVV. The method of Embodiment RRR, wherein if a measured P-wave amplitude is less than about 1 mV over the EGM test period, the IMD re-starts the EGM test sequence; or moves to step (5) and re-starts the EGM test sequence at a later time.
Embodiment WWW. The method of Embodiment RRR, wherein the IMD measures the number of cardiac sensed events, and terminates the EGM test sequence if a measured heart rate is less than a predetermined value.
Embodiment XXX. The method of Embodiment RRR, wherein the IMD performs the R-wave test sequence on a predetermined quantity of the measured cardiac sensed events with the lowest amplitudes.
Embodiment YYY. The method of Embodiment RRR, wherein the IMD performs the P-wave test sequence on a predetermined quantity of the measured cardiac sensed events with the lowest amplitudes.
Embodiment ZZZ. The method of any of Embodiments LLL to YYY, wherein the IMD paces the heart of the patient at 90 bpm in VVI mode for 30 seconds at a pacing output of about 2.5 V in step (5) to determine a qualification of pacing capture threshold (PCT).
Embodiment AAAA. The method of any of Embodiments LLL to ZZZ, wherein the IMD paces the heart of the patient at 90 bpm in AAI mode for 30 seconds at a pacing output of about 1 V in step (5) to determine a qualification of pacing capture threshold (PCT).
Embodiment BBBB. A method comprising:
detecting, by an implantable medical device (IMD), attachment to the IMD of at least one implantable medical lead, wherein the at least one implantable medical lead comprises at least one electrode;
triggering by the IMD, based on the detecting of the attachment to the IMD of the at least one medical lead, a device test sequence in which the IMD performs the following steps:
(1) periodically detecting an impedance for at least one electrical path that includes the at least one electrode, and determining, based on whether the impedance detected by the IMD is within a passing range, a connection status of the IMD to the at least one electrode;
(2) sensing a ventricle of the heart in OVO mode;
(3) comparing, in OVO mode, over an EGM test period, cardiac sensed event amplitudes in an electrogram of the patient over an EGM test period against a predetermined threshold;
(4) measuring, in OVO mode, current of injury (COI) parameters in the electrogram of the patient; and
(5) pacing the heart of the patient in VVI mode to determine a pacing capture threshold.
Embodiment CCCC. The method of Embodiment BBBB, wherein steps (3)-(4) are performed in parallel.
Embodiment DDDD. The method of any of Embodiments BBBB to CCCC, wherein the IMD paces the heart in VVI mode for about 5 seconds to about 30 seconds in step (5).
Embodiment EEEE. The method of Embodiment DDDD, wherein following step (5), the IMD performs device test sequence step (4) in OVO mode.
Embodiment FFFF. The method of Embodiment DDDD, wherein the IMD performs steps (3)-(4) sequentially until the PCT is determined.
Embodiment GGGG. The method of Embodiment FFFF, wherein the IMD performs step (4) for a predetermined time and compares a measured COI value to the measured COI value obtained in a previous time period.
Embodiment HHHH. The method of Embodiment DDDD, wherein the IMD measures current of injury (COI) parameters in an electrogram of the patient by determining at least one of the following: a maximum amplitude of an ST segment, an amplitude of the ST segment 80 milliseconds from a beginning of the segment, an area under a wave curve from an R-wave start to the end of the ST segment, and an area under the ST segment.
Embodiment IIII. A method for implanting a prosthetic heart valve in a heart of a patient, the method comprising:
detecting, by an implantable medical device (IMD), attachment to the IMD of at least one implantable medical lead, wherein the at least one implantable medical lead comprises at least one electrode;
triggering by the IMD, based on the detecting of the attachment to the IMD of the at least one medical lead, a device test sequence in which the IMD performs the following steps:
(1) detecting an impedance for at least one electrical path that includes the at least one electrode to determine a connection status of the IMD to the at least one electrode;
(2) comparing, over an EGM test period, cardiac sensed event amplitudes in an electrogram of the patient over an EGM test period against a predetermined threshold; and
(3) monitoring pacing capture threshold (PCT); and
delivering, during or after performance by the IMD of the device test sequence, a valve component in a radially compressed delivery configuration to a location within a native heart valve; and
deploying the valve component such that the valve component expands from the radially compressed delivery configuration to a radially expanded deployed configuration.
Embodiment JJJJ. The method of Embodiment IIII, wherein the IMD performs qualification tests (1)-(2) sequentially.
Embodiment KKKK. The method of any of Embodiments IIII to JJJJ, wherein the IMD performs qualification tests (1)-(2) in parallel.
Embodiment LLLL. The method of any of Embodiments IIII to KKKK, wherein the IMD performs qualification tests (2)-(3) following completion of qualification test (1).
Embodiment MMMM. The method of any of Embodiments IIII to LLLL, wherein the IMD measures current of injury (COI) parameters in an electrogram of the patient prior to, during, or after, step (3).
Embodiment NNNN. The method of Embodiment MMMM, wherein the IMD measures the COI parameters following the completion of qualification test (1).
Embodiment OOOO. The method of Embodiment MMMM, wherein the IMD measures the COI parameters following the completion of qualification test (1), and in parallel with qualification test (2).
Embodiment PPPP. The method of Embodiment MMMM, wherein if the IMD completes the qualification tests (1)-(3) over the evaluation period, the IMD generates a confirmation signal.
Embodiment QQQQ. A system comprising:
at least one implantable medical lead comprising one or more electrodes;
an implantable medical device (IMD) coupled to the at least one lead, wherein the at least one lead senses a cardiac electrogram (EMG) signal of a patient via the electrodes; and
wherein the IMD comprises a processor that causes the IMD to initiate following coupling to the at least one lead, a device test sequence in which the IMD performs any of the methods of claims 1-94.
Embodiment RRRR. The system of Embodiment QQQQ, wherein the IMD comprises an impedance measurement module, and the processor controls the impedance measurement module to measure in qualification test (1) an impedance of each of one or more electrical paths that include the electrodes on the at least one implantable medical lead.
Embodiment SSSS. The system of Embodiments QQQQ to RRRR, further comprising an external programmer that presents an alert to a user in response to one or more of the qualification tests.
Embodiment TTTT. The system of Embodiment SSSS, wherein the external programmer displays an EGM of the patient.
Embodiment UUUU. The system of any of Embodiments QQQQ to TTTT, further comprising an electrocardiogram (ECG) monitor.
Embodiment VVVV. The system of any of Embodiments QQQQ to UUUU, wherein the IMD comprises at least one of a temporary or permanent pacemaker, a cardioverter, and a defibrillator.
Embodiment WWWW. The system of any of Embodiments QQQQ to VVVV, wherein the IMD comprises a stimulation module, and the processor causes the stimulation module to pace a heart of a patient prior to or after detecting a lead impedance in a passing range.
Embodiment XXXX. The system of any of Embodiments QQQQ to WWWW, wherein the IMD comprises a stimulation module, and the processor causes the stimulation module to initiate cardiac pacing prior to initiation of the device test sequence.
Embodiment YYYY. The system of Embodiment XXXX, wherein the stimulation module paces the heart in VOO, AOO, VVI or AAI mode.
Embodiment ZZZZ. The system of any of Embodiments QQQQ to YYYY, wherein the processor causes the IMD to measure current of injury (COI) parameters in an electrogram of the patient.
Embodiment AAAAA. A computer-readable medium comprising instructions that cause a processor to:
following connection of the implantable medical device (IMD) to at least one lead, the lead comprising an electrode, controlling the IMD to automatically initiate, without input from an external programming device, a device test sequence in which the IMD performs the following qualification tests over an evaluation period:
(1) detecting an impedance for at least one electrical path that includes the at least one electrode to determine a connection status of the IMD to the at least one electrode; and
(2) comparing, over an EGM test period, cardiac sensed event amplitudes in an electrogram of the patient over an EGM test period against a predetermined threshold.
Embodiment BBBBB. The computer-readable medium of Embodiment AAAAA, wherein the processor controls the IMD to perform a qualification test (3): monitoring pacing capture threshold (PCT).
Embodiment CCCCC. The computer readable medium of Embodiments AAAAA to BBBBB, wherein the processor further causes the IMD to monitor current of injury (COI) parameters in an electrogram of the patient.
This application claims the benefit of U.S. Provisional patent application Ser. No. 63/264,252 filed on Nov. 18, 2021, the entire contents of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63264252 | Nov 2021 | US |
