TREATMENT OF CONGESTIVE HEART FAILURE WITH ELECTRICAL STIMULATION, AND ASSOCIATED SYSTEMS AND METHODS
Systems and methods for treating congestive heart failure with high frequency stimulation are disclosed. A representative method for treating a patient includes applying an electrical signal having a frequency of from about 1 kHz to about 100 kHz to the patient via a treatment system that includes a signal delivery element in electrical communication with the patient's vagus nerve at a portion of the vagus nerve located at or proximate to the anterior interventricular junction of the patient's heart. The method can further include automatically detecting at least one physiological parameter of the patient, automatically determining at least one of an ejection fraction of the patient's heart and a correlate of the ejection fraction based on the detected parameter, and automatically adjusting the applied signal based on the determined ejection fraction.
The present application claims priority to pending U.S. Provisional Application No. 62/286,892, filed Jan. 25, 2016, and is incorporated herein by reference.
TECHNICAL FIELDThe present technology is directed generally to treatment of congestive heart failure with electrical stimulation, and associated systems and methods.
BACKGROUNDCongestive heart failure (CHF) is a chronic condition characterized by a reduction in contraction strength (e.g., contractility) of one or both of the main pumping chambers of the heart the left and right ventricles. Reduced contractility of the ventricles reduces the volume of blood ejected by each ventricle per heart beat (e.g., stroke volume). When this occurs, the heart cannot pump blood with normal efficiency, and blood and other fluids begin to build up within the cardiovascular system and other parts of the body, such as the lungs, liver, abdomen, and lower extremities. In some cases of CHF, the myocardium (e.g., heart muscle tissue) becomes so weakened that the ventricles stretch or dilate, thereby damaging the Purkinje fibers located in the walls of the ventricles. The Purkinje fibers are responsible for carrying the contraction impulse to the myocardium of the ventricles, and thus damage to the Purkinje fibers by the dilated ventricles compromises the electrical conduction system of the heart and reduces the synchronization of contractility, further compromising the ejection fraction. Accordingly, there is a need for systems and methods for treating congestive heart failure.
The present technology is directed generally to systems for treating congestive heart failure (CHF), and in particular, to systems for treating CHF by improving contraction strength of the left and/or right ventricles via electrical stimulation. In one embodiment, the present technology includes a treatment system having an implantable signal generator and a signal delivery element configured to apply an electrical signal to a parasympathetic nerve innervating a portion of a patient's heart. The system includes one or more real-time feedback mechanisms for evaluating the efficacy of the applied signal and automatically adjusting the applied signal based on the efficacy. For example, in some embodiments the treatment system can automatically determine an ejection fraction of the patient's heart and adjust one or more parameters of the applied electrical signal based on the ejection fraction.
Definitions of selected terms are provided under heading 1.0 (“Definitions”). General aspects of the anatomical and physiological environment in which the disclosed technology operates are described below under heading 2.0 (“Introduction”) with reference to
As used herein, “vagus nerve” refers to any of the following: portions of the left vagus nerve, the right vagus nerve, and/or the cervical vagus nerve, branches of the vagus nerve such as the superior cardiac nerve, superior cardiac branch, and inferior cardiac branch, and the vagus trunk. Similarly, stimulation of the vagus nerve is described herein by way of illustration and not limitation, and it is to be understood that in some embodiments of the present technology, other autonomic and/or parasympathetic nerves and/or parasympathetic tissue are stimulated, including sites where the vagus nerve innervates a target organ, vagal ganglia, nerves in the epicardial fat pads, a carotid artery, a jugular vein (e.g., an internal jugular vein), a carotid sinus, a coronary sinus, a vena cava vein, a pulmonary vein, and/or a right ventricle, for treatment of heart conditions or other conditions.
As used herein, “high frequency” or “HF” refers to a frequency of from about 1 kHz to about 100 kHz, or from about 1.2 kHz to about 100 kHz, or from about 1.5 kHz to about 100 kHz, or from about 2 kHz to about 50 kHz, or from about 3 kHz to about 20 kHz, or from about 3 kHz to about 15 kHz, or from about 5 kHz to about 15 kHz, or from about 3 kHz to about 10 kHz, or 1 kHz, 2 kHz, 3 kHz, 4 kHz, 5 kHz, 8 kHz, 9 kHz, 10 kHz, 11 kHz, 12 kHz, 15 kHz, 20 kHz, 50 kHz, or 100 kHz. As used herein, the term “about” refers to values within +/−10% of the stated value. Moreover, as used herein, “low frequency” or “LF” refers to a frequency less than about 1 KHz.
As used herein, “real-time” refers to within 10 seconds or less, within 5 seconds or less, within 3 seconds or less, within 2 seconds or less, within 1 second or less, within 0.5 seconds or less, within 0.25 seconds or less, and within 0.1 seconds or less.
2.0 IntroductionThe signal generator 102 can transmit signals (e.g., electrical signals or therapy signals) to the signal delivery element 104 that up-regulate (e.g., stimulate or excite) and/or down-regulate (e.g., block or suppress) target nerves (e.g., local vagal nerves). As used herein, and unless otherwise noted, to “modulate,” “stimulate,” or provide “modulation” or “stimulation” to the target nerves refers generally to having either type of the foregoing effects on the target nerves. The signal generator 102 can include a machine-readable (e.g., computer-readable) medium containing instructions for generating and transmitting suitable therapy signals. The signal generator 102 and/or other elements of the treatment system 100 can include one or more processors 110, memories 112 and/or input/output devices. Accordingly, the process of providing electrical signals, detecting physiological parameters of the patient, determining ejection fraction, adjusting the modulation signal, and/or executing other associated functions can be performed by computer-executable instructions contained by computer-readable media located at the signal generator 102 and/or other system components. The signal generator 102 can include multiple portions, elements, and/or subsystems (e.g., for directing signals in accordance with multiple signal delivery parameters) housed in a single housing, as shown in
The signal delivery system 101 can include one or more sensing elements 140 for detecting one or more physiological parameters of the patient before, during, and/or after the application of electrical therapy signals. In some embodiments, one or more of the sensing elements 140 can be carried by the signal generator 102, the signal delivery element 104, and/or other implanted components of the system 101. In other embodiments, the sensing element(s) 140 can be an extracorporeal or implantable device separate from the signal generator 102 and/or signal delivery element 104. Representative sensing elements 140 include one or more of: an electrocardiogram (“ECG”) unit, an impedance cardiography unit, a subcutaneous sensor, a ventricular sensor, an activity sensor (e.g., an accelerometer), a ventricular intracardiac sensor, an atrial intracardiac sensor, a temperature sensor, a flow rate sensor, a chemical sensor, a biosensor, an electrochemical sensor, a hemodynamic sensor, an optical sensor and/or other suitable sensing devices. Physiological parameters detected by the sensing element(s) 140 include heart rate, blood pressure, blood flow rate, activity level, ECG readings, impedance cardiography readings, ventricular and/or atrial pressure, and/or any correlates and/or derivatives of the foregoing parameters (e.g., raw data values, including voltages and/or other directly measured values).
In a representative embodiment, the signal delivery system 101 is configured to operate in either a “calibration mode” or an “active mode.” In the calibration mode, the signal delivery system 101 is configured to apply a low frequency electrical signal (also referred to herein as the “LF calibration signal”) via the signal delivery element 104 at the treatment site to determine a representative (e.g., maximum) signal amplitude that can be applied during subsequent treatment. In one embodiment, for example, the maximum signal amplitude is determined during the calibration mode to be the lower of: (1) the amplitude at which direct, immediate changes are observed to the heart rate, myocardial activation, or chamber sequencing, and (2) the amplitude which creates sensations which are perceived by the patient. In a particular embodiment, the signal delivery system 101 is also configured to apply a high frequency electrical signal (referred to herein as the “HF calibration signal”) when in the calibration mode to validate the maximum signal amplitude identified by the LF calibration signal. In the active mode, the signal delivery system 101 is configured to apply a high frequency electrical signal (also referred to herein as the “HF treatment signal” or “HF therapy signal”) at the treatment site to modulate the parasympathetic nerves proximate the treatment site. Parameters of the electrical signals applied by the signal delivery system 101 during calibration mode and/or active mode can be (1) automatically adjusted in response to a feedback mechanism and/or in accordance with a preset program (described in greater detail with reference to
In some embodiments, the signal generator 102 can obtain power to generate the therapy signals from an external power source 114. The external power source 114 can transmit power to the implanted signal generator 102 using electromagnetic induction (e.g., RF signals). For example, the external power source 114 can include an external coil 116 that communicates with a corresponding internal coil (not shown) within the implantable signal generator 102. The external power source 114 can be portable for ease of use.
In another embodiment, the signal generator 102 can obtain the power to generate therapy signals from an internal power source, in addition to or in lieu of the external power source 114. For example, the implanted signal generator 102 can include a non-rechargeable battery or a rechargeable battery to provide such power. When the internal power source includes a rechargeable battery, the external power source 114 can be used to recharge the battery. The external power source 114 can in turn be recharged from a suitable power source (e.g., conventional wall power).
During at least some procedures, an external programmer 120 (e.g., a trial modulator) can be coupled to the signal delivery element 104 during an initial procedure, prior to implanting the signal generator 102. For example, a practitioner (e.g., a physician and/or a company representative) can use the external programmer 120 in calibration mode to vary the signal parameters provided to the signal delivery element 104 in real-time, and select optimal or particularly efficacious signal parameters and/or signal delivery element 104 placement, as discussed in greater detail below with reference to
After a trial period with the external programmer 120, the practitioner can implant the implantable signal generator 102 within the patient P for longer term treatment. The signal delivery parameters provided by the signal generator 102 can still be updated after the signal generator 102 is implanted, via a wireless physician's programmer 124 (e.g., a physician's remote).
As shown in
In a particular embodiment, the signal delivery system 101 (
Once the maximum treatment signal amplitude has been determined, the system 101 (
Application of the HF treatment signal at the treatment site (e.g., at or proximate an epicardial fat pad) is expected to modulate one or more vagal nerves at or proximate to the treatment site, thereby improving parasympathetic tone and cardiac contractility. One way to assess contractility and/or the efficacy of the treatment is by measuring ejection fraction, or the percentage of blood pumped out of the heart during each beat. An increase in ejection fraction indicates improved contractility and, likewise, a decrease in ejection fraction indicates reduced contractility. Under resting conditions, healthy adults have an average ejection fraction between 50% and 75%. Below 50%, the patient may experience a variety of symptoms, including shortness of breath, inability to exercise, swelling of the feet and lower legs, fatigue, weakness, and rapid or irregular heartbeat. Below 30%, the patient's quality of life is minimal and death may be imminent.
When the signal delivery system 101 (
In block 514, the processor 110 (
As indicated by block 530, if the EF measurement is less than the target EF threshold, the processor 110 (
As indicated by block 520, if the EF measurement is greater than or equal to the target EF threshold, the processor 110 (
It will be appreciated that in any of the above embodiments, the signal delivery system 101 (
Embodiments of the presently disclosed technology are described in the following examples. A method for treating congestive heart failure in a patient in accordance with one example includes applying an electrical signal to the patient via a treatment system that includes a signal delivery element in electrical communication with the patient's vagus nerve at a portion of the vagus nerve located at or proximate to the anterior interventricular junction of the patient's heart, with the electrical signal having a frequency of from about 1 kHz to about 100 kHz. The method further includes automatically detecting at least one physiological parameter of the patient, automatically determining at least one of an ejection fraction of the patient's heart and a correlate of the ejection fraction based on the detected parameter, and automatically adjusting the applied signal based on the determined ejection fraction. In some embodiments of the method, automatically adjusting the applied signal includes stopping the application of the applied signal in response to detecting an ejection fraction greater than or equal to a target ejection fraction threshold. In these and other embodiments, automatically adjusting the applied signal includes increasing at least one of an amplitude of the applied signal and a pulse width of the applied signal in response to detecting an ejection fraction less than a target ejection fraction threshold and/or automatically adjusting the applied signal includes decreasing at least one of an amplitude of the applied signal and a pulse width of the applied signal in response to detecting an ejection fraction greater than or equal to a target ejection fraction threshold. In some embodiments, automatically detecting a physiological parameter includes automatically detecting the patient's heart rate, and automatically adjusting the applied signal includes increasing at least one of an amplitude of the applied signal and a pulse width of the applied signal in response to the increase in the patient's heart rate. Further, in at least some embodiments of the method, applying the electrical signal occurs at a first time and automatically adjusting the applied signal includes applying the electrical signal at a second time in response to detecting an ejection fraction less than the target ejection fraction threshold. In a particular embodiment, applying the electrical signal includes applying the signal to the patient via a lead positioned at or proximate to the atrial-ventricular fat pads of the patient's heart. In certain embodiments of the method, applying the electrical signal includes applying the signal with a pulse width less than or equal to 1/(2×the frequency of the signal). In further embodiments, the treatment system includes an implantable treatment system. In yet further embodiments, the at least one detected physiological parameter includes at least one of the patient's heart rate, the patient's blood pressure, and the patient's blood flow rate.
A method for treating congestive heart failure in a patient in accordance with another representative example includes applying an electrical signal having a frequency of from about 1 kHz to about 100 kHz to an epicardial fat pad of the patient's heart, automatically monitoring an ejection fraction of the patient, automatically comparing the monitored ejection fraction value to a predetermined threshold, and based on the comparison, automatically adjusting the applied signal. In some embodiments of the method, automatically adjusting the applied signal includes stopping the application of the applied signal in response to detecting an ejection fraction greater than or equal to a target ejection fraction threshold. In these and other embodiments, automatically adjusting the applied signal includes increasing at least one of an amplitude of the applied signal and a pulse width of the applied signal in response to detecting an ejection fraction less than a target ejection fraction threshold and/or automatically adjusting the applied signal includes decreasing at least one of an amplitude of the applied signal and a pulse width of the applied signal in response to detecting an ejection fraction greater than or equal to a target ejection fraction threshold. In a particular embodiment of the method, applying the electrical signal occurs at a first time, and wherein automatically adjusting the applied signal includes applying the electrical signal at a second time in response to detecting an ejection fraction less than the target ejection fraction threshold.
Still a further representative example of a system for treating congestive heart failure in a patient in accordance with the present technology includes an electrical signal generator having a computer readable storage medium, and an implantable signal delivery element coupled to the signal generator. The signal generator can be configured to be positioned proximate an epicardial fat pad of the patient and apply an electrical signal having a frequency of from about 1 kHz to about 100 kHz to neural tissue proximate and/or within the epicardial fat pad. In some embodiments of the system, the computer-readable storage medium has instructions that, when executed, determine an ejection fraction of the patient's heart in real-time and adjust the signal applied by the signal delivery element in response to the determined ejection fraction. In a particular embodiment, the system further comprises a sensor in communication with the computer-readable storage medium. In at least some of such embodiments, the sensor is configured to detect a physiological parameter of the patient, and the instructions, when executed, calculate the ejection fraction based on the physiological parameter. In a certain embodiment of the system, the signal generator is an implantable signal generator. In further embodiments of the system, the instructions, when executed, and in response to a determined ejection fraction greater than or equal to a predetermined target threshold, cease to apply the electrical signal. In these and other embodiments, the instructions, when executed, and in response to a determined ejection fraction less than or equal to a predetermined target threshold, start application of the electrical signal and/or in response to a determined ejection fraction less than or equal to a predetermined target threshold, increase at least one of an amplitude or a pulse width of the electrical signal. In a representative embodiment of the system, the signal delivery element is configured to be positioned within a coronary blood vessel of the patient.
From the foregoing, it will be appreciated that specific embodiments of the disclosed technology have been described herein for purposes of illustration, but that various modifications may be made without deviating from the technology. For example, in some embodiments the system 101 (
Certain aspects of the technology described in the context of particular embodiments may be combined or eliminated in other embodiments. For example, in some embodiments the signal generator 102 (
To the extent any materials incorporated herein by reference conflict with the present disclosure, the present disclosure controls.
Claims
1-49. (canceled)
50. A method for treating congestive heart failure in a patient, comprising:
- applying an electrical signal to the patient's vagus nerve via a signal delivery element positioned in electrical communication with the patient's vagus nerve at a portion of the vagus nerve located at or proximate to the anterior interventricular junction of the patient's heart, wherein the electrical signal has a frequency in a frequency range of from about 1 kHz to about 100 kHz, and wherein the electrical signal excites the vagus nerve;
- detecting at least one physiological parameter of the patient via one or more sensing elements;
- based on the detected parameter, determining an ejection fraction indicator that is at least one of an ejection fraction of the patient's heart or a correlate of the ejection fraction; and
- adjusting the applied signal based on the determined ejection fraction indicator.
51. The method of claim 50 wherein the signal delivery device is positioned at or proximate to the atrial-ventricular fat pads of the patient's heart.
52. The method of claim 50 wherein adjusting the applied signal includes stopping application of the applied signal in response to detecting an ejection fraction indicator greater than or equal to a target ejection fraction indicator threshold.
53. The method of claim 50 wherein adjusting the applied signal includes decreasing an amplitude of the applied signal and/or decreasing a pulse width of the applied signal in response to detecting an ejection fraction indicator greater than or equal to a target ejection fraction indicator threshold.
54. The method of claim 50 wherein adjusting the applied signal includes increasing an amplitude of the applied signal and/or increasing a pulse width of the applied signal in response to detecting an ejection fraction indicator less than a target ejection fraction indicator threshold.
55. The method of claim 50 wherein adjusting the applied signal based on the determined ejection fraction indicator includes automatically adjusting the applied signal.
56. The method of claim 50 wherein the at least one detected parameter includes at least one of the patient's heart rate, the patient's blood pressure, and the patient's blood flow rate.
57. The method of claim 50 wherein the frequency range is from about 3 kHz to about 20 kHz.
58. A method for treating congestive heart failure in a patient, comprising:
- applying an electrical signal to the patient's vagus nerve to increase a contraction strength of a left ventricle and/or a right ventricle of the patient's heart, via a signal delivery element positioned in electrical communication with the patient's vagus nerve at a portion of the vagus nerve located at or proximate to the anterior interventricular junction of the patient's heart, wherein the electrical signal has a frequency in a frequency range of from about 1 kHz to about 100 kHz;
- detecting at least one physiological parameter of the patient via one or more sensing elements;
- based on the detected parameter, determining an ejection fraction indicator that is at least one of an ejection fraction of the patient's heart or a correlate of the ejection fraction; and
- adjusting the applied signal based on the determined ejection fraction indicator.
59. The method of claim 58 wherein the signal delivery element is positioned at or proximate to the atrial-ventricular fat pads of the patient's heart.
60. The method of claim 58 wherein:
- detecting the physiological parameter includes detecting the patient's heart rate; and
- adjusting the applied signal includes increasing at least one of an amplitude of the applied signal and a pulse width of the applied signal in response to the increase in the patient's heart rate.
61. The method of claim 58 wherein adjusting the applied signal based on the determined ejection fraction indicator includes automatically adjusting the applied signal.
62. The method of claim 58 wherein applying the electrical signal increases a contraction strength of the left ventricle.
63. The method of claim 58 wherein the frequency range is from about 5 kHz to about 15 kHz.
64. A method for treating congestive heart failure in a patient, comprising:
- programming a patient treatment system to: deliver an electrical signal to the patient's vagus nerve via a signal delivery element positioned in electrical communication with the patient's vagus nerve at a portion of the vagus nerve located at or proximate to the anterior interventricular junction of the patient's heart, wherein the electrical signal has a frequency in a frequency range of from about 1 kHz to about 100 kHz, and wherein the electrical signal increases a contraction strength of a left ventricle and/or a right ventricle of the patient's heart; receive at least one physiological parameter of the patient detected via one or more sensing elements; based on the received physiological parameter, determine an ejection fraction indicator that is at least one of an ejection fraction of the patient's heart or a correlate of the ejection fraction; and adjust the applied signal based on the determined ejection fraction indicator.
65. The method of claim 64 wherein the patient treatment system includes an implantable signal generator, and wherein programming the patient treatment system to deliver the electrical signal includes programming the implantable signal generator to deliver the electrical signal.
66. The method of claim 64 wherein programming the patient treatment system to adjust the applied signal includes programming the patient treatment system to automatically adjust the applied signal.
67. The method of claim 64 wherein programming the patient treatment system to adjust the applied signal includes programming the patient treatment system to:
- decrease an amplitude and/or a pulse width of the applied signal in response to detecting an ejection fraction indicator greater than or equal to a target ejection fraction indicator threshold; and
- increase the amplitude and/or the pulse width in response to detecting an ejection fraction indicator less than a target ejection fraction indicator threshold.
68. The method of claim 64 wherein the electrical signal upregulates neural tissue at or proximate the patient's coronary sinus.
69. The method of claim 64 wherein the electric signal increases the contraction strength of the left ventricle.
Type: Application
Filed: Jan 31, 2023
Publication Date: Aug 31, 2023
Inventors: James R. Thacker (Homer, AK), Kerry Bradley (Glendale, CA)
Application Number: 18/103,652