The subject matter discussed herein is directed the treatment of heart tissue.
As is well known, the heart has four chambers for receiving and pumping blood to various parts of the body. During normal operation of the heart, oxygen-poor blood returning from the body enters the right atrium. The right atrium fills with blood and eventually contracts to expel the blood through the tricuspid valve to the right ventricle. Contraction of the right ventricle ejects the blood in a pulse-like manner into the pulmonary artery and each lung. The oxygenated blood leaves the lungs through the pulmonary veins and fills the left atrium. The left atrium fills with blood and eventually contracts to expel the blood through the mitral valve to the left ventricle. Contraction of the left ventricle forces blood through the aorta to eventually deliver the oxygenated blood to the rest of the body.
Myocardial infarction (i.e., heart attack) can result in congestive heart failure. Congestive heart failure is a condition wherein the heart can not pump enough blood. When patients have a heart attack, part of the circulation to the heart wall muscle is lost usually due to a blood clot which dislodges from a larger artery and obstructs a coronary artery. If the clot is not dissolved within about 3 to 4 hours, the muscle which lost its blood supply necroses and subsequently becomes a scar. The scarred muscle is not contractile, and therefore it does not contribute to the pumping ability of the heart. In addition, the scarred muscle is elastic (i.e., floppy) which further reduces the efficiency of the heart because a portion of the force created by the remaining healthy muscle bulges out the scarred tissue (i.e., ventricular aneurism) instead of pumping the blood out of the heart.
Congestive heart failure is generally treated with lots of rest, a low-salt diet, and medications such as A.C.E. inhibitors, digitalis, vasodilators and diuretics. In some myocardial infarction instances, the scarred muscle is cut out of the heart and the remaining portions of the heart are sutured (i.e., aneurismechtomy). In limited circumstances a heart transplant may be performed. The condition is always progressive and eventually results in patient death.
Collagen-containing tissue is ubiquitous in normal human body tissues. Collagen makes up a substantial portion of scar tissue, including cardiac scar tissue resulting from healing after a heart attack. Collagen demonstrates several unique characteristics not found in other tissues. Intermolecular cross links provide collagen-containing tissue with unique physical properties of high tensile strength and substantial elasticity. A property of collagen is that collagen fibers shorten when heated. This molecular response to temperature elevation is believed to be the result of rupture of the collagen stabilizing cross links and immediate contraction of the collagen fibers to about one-third of their original length. If heated to approximately 70 degrees Centigrade, the cross links will again form at the new dimension. If the collagen is heated above about 85 degrees Centigrade, the fibers will still shorten, but crosslinking will not occur, resulting in denaturation. The denatured collagen is quite expansile and relatively inelastic. In living tissue, denatured collagen is replaced by fibroblasts with organized fibers of collagen than can again be treated if necessary. Another property of collagen is that the caliber of the individual fibers increases greatly, over four fold, without changing the structural integrity of the connective tissue.
In an embodiment, a system and method for treating an affected portion of heart tissue including, but not limited to, inserting a mono-polar or bi-polar electrode into heart tissue at least proximal to the affected portion; energizing the electrode to emit a radio frequency (RF) signal to heat the affected portion; and measuring a temperature of the affected portion, wherein the energizing of the electrode is associated with the measured temperature. In an embodiment, the electrode is no longer energized upon the measured temperature reaching a desired temperature. In an embodiment, the method further comprises transmitting a signal associated with the measured temperature to a processor, wherein the processor compares the measured temperature to a designated termination temperature. In an embodiment, power supplied to energize the electrode is altered based on the transmitted signal. In an embodiment, inserting further comprises rotating the electrode about an axis into the heart tissue, wherein the electrode includes a helical configuration. The electrode may be inserted directly into the affected portion or inserted directly into healthy tissue to treat the affected portion in at least one of below the healthy tissue or adjacent to the healthy tissue. In an embodiment, the desired temperature is in the range of about 40 degrees Celsius to about 75 degrees Celsius.
The accompanying drawings, which are incorporated into and constitute a part of this specification, illustrate one or more embodiments of the present invention and, together with the detailed description, serve to explain the principles and implementations of the invention.
In the drawings:
Example embodiments are described herein in the context of a system and method to heal an infarct tissue. Those of ordinary skill in the art will realize that the following description is illustrative only and is not intended to be in any way limiting. Other embodiments will readily suggest themselves to such skilled persons having the benefit of this disclosure. Reference will now be made in detail to implementations of the example embodiments as illustrated in the accompanying drawings. The same reference indicators will be used throughout the drawings and the following description to refer to the same or like items.
In the interest of clarity, not all of the routine features of the implementations described herein are shown and described. It will, of course, be appreciated that in the development of any such actual implementation, numerous implementation-specific decisions must be made in order to achieve the developer's specific goals, such as compliance with application- and business-related constraints, and that these specific goals will vary from one implementation to another and from one developer to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of engineering for those of ordinary skill in the art having the benefit of this disclosure.
In accordance with this disclosure, the components, process steps, and/or data structures described herein may be implemented using various types of operating systems, computing platforms, computer programs, and/or general purpose machines. In addition, those of ordinary skill in the art will recognize that devices of a less general purpose nature, such as hardwired devices, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), or the like, may also be used without departing from the scope and spirit of the inventive concepts disclosed herein. Where a method comprising a series of process steps is implemented by a computer or a machine and those process steps can be stored as a series of instructions readable by the machine, they may be stored on a tangible medium such as a computer memory device (e.g., ROM (Read Only Memory), PROM (Programmable Read Only Memory), EEPROM (Electrically Eraseable Programmable Read Only Memory), FLASH Memory, Jump Drive, and the like), magnetic storage medium (e.g., tape, magnetic disk drive, and the like), optical storage medium (e.g., CD-ROM, DVD-ROM, paper card, paper tape and the like) and other types of program memory.
In general, a power generating device provides modulated power to a helical shaped electrode which emits RF signals at a selected frequency and magnitude when energized. The RF signals emitted from the electrode are converted into heat by the affected tissue, whereby heating of the affected tissue to a desired temperature causes reduction of the surface area in the affected infarct tissue without ablating the affected tissue or damaging the healthy tissue surrounding the affected area.
As shown in
In an embodiment, the coupling connector 110 includes an inner shaft 114 which houses a portion of the thermocouple sensor 112. An aperture at the end in the coupling connector 110 may be formed in communication with the inner shaft 114 to allow a portion of the thermocouple sensor 112 to extend out of the coupling connector 110. It should be noted that the thermocouple and coupling connector configuration shown in
As shown in the embodiments in
In an embodiment, the tissue insertion component 106 of the repair device 100 is configured to rotate about axis A to allow the electrode 108 to be inserted into and removed from the affected infarct tissue. When the electrode 108 initially comes into contact with the tissue, rotation of the electrode 108 about axis A will cause the electrode 108 to undergo a screw like motion into the tissue, thereby inserting itself therein. This is at least partially due to the helical configuration of the electrode 108 as well as the sharp tip of the electrode 108 as shown in
In an embodiment, the flexible cable 104 is rotated manually at the distal end by the user to screw the electrode 108 into and from the tissue. The user may rotate the flexible cable 104 itself or may rotate the flexible cable by using a handle 124 (
However, considering that the end of the cable 104 may be rigidly connected to the RF generating device 150 and/or other devices, rotation of the cable 104 after a few turns may twist the cable 104 and make it difficult to manipulate or even damage the device. Accordingly, a freely rotatable coupling device, discussed below, may be incorporated in an embodiment. It should be noted that a combination of the rotating devices described herein may be incorporated into one tissue repair device.
The first portion 126A is shown in
The second portion 126B is shown in
In an embodiment, the first and second portions are fixedly attached to one another as an integrated component, as shown in
In an embodiment, the rotatable coupling device 126 is configured to measure and track the rotational movement of the flexible cable 104 during the procedure. Any appropriate type of sensor may be incorporated into the coupling device 126, whereby the sensor would track the number of rotations of the cable 104 (and thus the electrode 108) and send signals to a processor of a feedback system. The feedback system may be a computer program run on a host computer which is configured to store, analyze and display the measured information to the user to keep track of how many revolutions are performed and/or needed to effective screw the electrode 108 to a desired depth in the heart tissue. In an embodiment that the user utilizes both the handle 124 as well as the coupling device 126, sensors may be incorporated in the handle 124 and coupling device 126 to measure and display data of the relative rotations of each. In another embodiment, an indicator is located directly on the handle 124 and/or coupling device 126 to indicate the number of rotations undergone during the procedure.
The RF generating device 150 provides modulated power to the resistive corkscrew electrode 108 to emit an RF signal at a selected frequency and magnitude. The frequency is in the range of 10 MHz to 1000 MHz. The RF signal emitted from the electrode 108 is converted into heat by the affected tissue, whereby heating of the affected tissue to a desired temperature causes reduction of the surface area in the affected infarct tissue without ablating the affected tissue or damaging the healthy tissue surrounding the affected area. The affected tissue is heated by the electrode 108 under dynamic conditions having variable strain created by the heart muscle itself which may aid in improving the reduction of the affected tissue's size and/or thickness.
The RF generating device 150 applies between 1 W to 40 W to the electrode 108 to effectively heat the affected tissue between 40° C. and 75° C. for optimum reduction of the affected tissue. In an embodiment, the RF generating device 150 has a single channel and delivers the power to the electrode 108 continuously. In an embodiment, the RF energy emitted at the electrode 108 may be multiplexed by applying the energy in different waveform patterns (e.g. sinusoidal wave, sawtooth wave, square wave) over time as appropriate. In an embodiment, the affected tissue is continuously heated by the electrode for a desired amount of time. It should be noted that other power levels, desired temperatures, desired time periods, and/or energy patterns are contemplated based on the type of affected tissue, materials used in the device 100, frequencies and other factors.
A feedback system may be employed to the electrode 108 for detecting appropriate feedback variables during the treatment procedure. In an embodiment, the thermocouple sensor 112 senses the temperature of the infarct tissue during treatment and sends those signals to a processor which provide feedback to allow the system 100 to automatically or manually modulate the power supplied by the RF generator 50 to the electrode 108. The thermocouple 112 senses the temperature of the tissue through its tip (
In an embodiment, the processor 122 compares the measured temperature with a desired or preprogrammed temperature and accordingly informs the user or automatically causes the RF generating device 150 to alter the power supplied to the electrode 108. As the thermocouple 112 measures the affected tissue reaching the desired temperature, the processor 122 continuously receives the information from the thermocouple 112 and provides signals to the RF generating device 150 to increase, decrease, modulate, reinitiate or terminate power to the electrode 108. In an example, the system 100 is configured such that the RF generating device 150 automatically terminates power supplied to the electrode 108 upon the thermocouple 112 indicating the affected tissue has reached the desired temperature. In an example, the system 100 automatically produces an audible sound and/or video display indicating that the affected tissue has reached the desired temperature. In an embodiment, the affected tissue is heated continuously by the electrode for a desired amount of time before or after the desired temperature has been reached. In an embodiment, the affected tissue is heated continuously by the electrode after the desired temperature has been reached until the infarct tissue shrinks or has been reduced a maximum allowable amount for a treatment. It is contemplated that a computer display coupled to the processor and is configured to provide graphical data of the sensed temperature of the tissue and/or a graphical simulation of the tissue treatment process. In an embodiment, a display may be used to show an actual video image of the electrode within the heart tissue in real time, whereby the surgeon is able to see the actual reduction of the infarct tissue as it is heated by the electrode. This provides visual feedback to the surgeon to alter or terminate the modulated power to the electrode if the infarct tissue is no longer shrinking.
In an embodiment, the thermocouple sensor 112 acts as a tissue depth limiting device. As shown in
The configuration of the electrode 108 allows flexibility in treating the affected tissue irrespective of the location of the affected tissue in the heart wall. In addition, the ability for the electrode 108 to be inserted directly into the tissue provides information as to the depth of the infarct tissue while potentially protecting one or both surfaces of the heart tissue. For example, the electrode 108 may be directly inserted into the infarct tissue to treat the affected tissue. The electrode 108 may be inserted into healthy heart tissue to treat and repair infarct tissue located adjacent to or below healthy tissue, without heating the healthy tissue. In the case of the infarct tissue being located below the healthy tissue, infarct tissue located proximal to or on the outer wall of the heart may be effectively treated even though the electrode is inserted from the heart's inner wall. In an embodiment, the electrode is inserted into healthy tissue which is adjacent to the infarct tissue to effectively treat and repair the infarct tissue without heating the healthy tissue. In an embodiment, the electrode may be inserted into healthy tissue located between two areas of infarct tissue to treat both areas simultaneously or individually without heating the healthy tissue. In contrast, the electrode may heat an affected tissue layer located between two healthy tissue layers without heating the healthy layers. In a scenario, the electrode may be heated using one or more heating patterns to allow a controlled depth heating of affected tissue areas interspersed within healthy tissue. Upon treating the infarct tissue, the electrode may be easily removed from the heart tissue and reinserted into another location in the heart to treat another infarct tissue or another area or portion of the previously treated infarct tissue.
In an embodiment, the tissue insertion device 106 has a mono-polar configuration, whereby a ground potential 118 is placed at a location not within the immediate proximity of the electrode 108. The mono-polar configuration allows RF signals emitted by the electrode 108 to spread over a larger area of the affected tissue considering the receiving ground potential is not in immediate proximity but a distance away from the electrode 108. The ground potential 118 can be a conductive grounded receiving wire similar in size to the electrode 108 which is placed on or near the patient's skin and may or may not be connected to the RF generating device 150. In an embodiment, the receiving electrode is placed on the patient's back during the procedure. In an embodiment, the receiving wire is placed in proximity to the location of the electrode 108 within the patient's heart to allow somewhat focused transmission of the RF signals to the receiving wire. In an embodiment, a polarity opposite to that emitted by the electrode 108 is applied to the receiving wire, whereby the opposite polarity can be generated by the RF generating device 150. In an embodiment, the device has a bi-polar configuration, one or more embodiments of which is described below.
In the embodiment shown in
In an embodiment, Mylar is used to form a bag-like structure 222 which is located around the collapsible tissue repair component 210 to completely enclose the struts 212, wire 214 and electrodes 218, 220, whereby the proximal end of the Mylar sheet 222 is connected to the ring 208. In an embodiment, the electrodes 218, 220 may be an integral part of the Mylar sheet 222. In an embodiment, the electrodes 218, 220 may be printed in electrically-conductive ink on the Mylar 222. In an embodiment, the Mylar sheet 222 itself can act as a restraint on the struts 212, thereby obviating the need for the wire 214. It should be noted that Mylar is an example material and other appropriate materials are contemplated for use with the device described herein.
As shown in
In operation for the embodiment in
It should be understood that other types of monitoring and locating systems could be used by a physician to monitor the location of a tissue repair device to properly insert the electrode into the affected infarct tissue. In an embodiment, an electrocardiogram (ECG/EKG) of the heart tissue may be used to monitor the position of the electrode and tissue repair device within the heart in real time. It would be preferred that the electrode or other portion of the tissue insertion device is made of a material which is able to be easily displayed in an ECG/EKG. Particulars of the ECG/EKG are well known in the art and are not described herein.
In an embodiment, magnetic resonance imaging (MRI) may be utilized to monitor the position of the tissue repair device within the heart in real time, whereby magnetic fields are used to orient and move the tissue repair device to the desired affected area. In an embodiment, the electrode of the tissue repair device may emit magnetic fields, instead of RF energy, to heat and thereby heal the affected infarct tissue.
In an embodiment, as shown in
Once it is determined that the electrode is at the desired position with respect to the infarct tissue, the physician rotates the flexible cable itself or a handle to rotate the corkscrew electrode to insert and engage the electrode into the infarct tissue (606). Alternatively, the cable may be rotated automatically. Modulated power is then applied to the electrode, whereby the electrode emits RF signals directly into the infarct tissue (608). A temperature sensor of the repair device may be used to sense the temperature of the infarct tissue. As stated above, the modulated power level is 1 W-40 W and the frequency of the signals is in the range of 10 megahertz to 1000 megahertz, to heat the scar tissue to a temperature sufficient to reduce the surface area of the scar without ablating the scar tissue or damaging the healthy tissue surrounding the infarct tissue. The scar tissue is heated in the range of about 40 degrees Celsius to about 75 degrees Celsius.
Once the infarct tissue has reached a desired temperature for a desired period of time, the treatment is completed. The period of time is between 1 and 2 minutes in an embodiment, although other periods of time are contemplated based on a variety of factors including, but not limited to, wattage, frequency, and size of electrode. Thereafter, the flexible cable is rotated the opposite direction than before to remove the electrode from the infarct tissue (610). Upon treating the infarct tissue, the electrode may be easily removed from the heart tissue and reinserted into another location in the heart to treat another infarct tissue or another area or portion of the previously treated infarct tissue. The tissue repair device is then removed from the catheter sleeve, wherein the catheter sleeve is then removed from the patient.
While embodiments and applications of this tissue repair device have been shown and described, it would be apparent to those skilled in the art having the benefit of this disclosure that many more modifications than mentioned above are possible without departing from the inventive concepts herein.
The present application is a continuation-in-part of co-pending U.S. patent application Ser. No. 11/035,657 filed Jan. 14, 2005, in the name of inventor Michael D. Laufer.
Number | Date | Country | |
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Parent | 11035657 | Jan 2005 | US |
Child | 11599167 | Nov 2006 | US |