Selective nerve fiber stimulation for treating heart conditions

Abstract

Apparatus is provided that includes an electrode device, adapted to be coupled to a vagus nerve of a subject, and a control unit, adapted to drive the electrode device to apply to the vagus nerve a current that reduces heart rate variability of the subject. Also provided is a method comprising applying to a vagus nerve of a subject a current that reduces heart rate variability of the subject.

1 - 80 . (canceled) 
     
     
         81 . Apparatus for treating a subject, comprising:
 an electrode device, adapted to be coupled to tissue selected from the group consisting of: a vagus nerve and an epicardial fat pad of the subject;   a heart rate sensor, configured to detect a heart rate of the subject, and to generate a heart rate signal responsive thereto; and   a control unit, adapted to:   receive the heart rate signal, and   responsive to determining that the heart rate is greater than a threshold value, which threshold value is greater than a normal heart rate, drive the electrode device to apply a current to the tissue, and configure the current so as to reduce the heart rate of the subject.   
     
     
         82 . The apparatus according to  claim 81 , wherein the control unit is adapted to configure the current so as to reduce the heart rate towards a target heart rate. 
     
     
         83 . The apparatus according to  claim 81 , wherein the control unit is adapted to drive the electrode device to apply the current in intermittent ones of a plurality of cardiac cycles of the subject. 
     
     
         84 . The apparatus according to  claim 81 , comprising an electrode selected from the list consisting of: an electrode for pacing the heart, and an electrode for defibrillating the heart, wherein the control unit is adapted to withhold driving the electrode device to apply the current to the tissue if the control unit is driving the electrode selected from the list. 
     
     
         85 . The apparatus according to  claim 81 , wherein the control unit is adapted to drive the electrode device to apply the current in respective pulse bursts in each of a plurality of cardiac cycles of the subject. 
     
     
         86 . The apparatus according to  claim 85 , comprising an electrocardiogram (ECG) monitor, adapted to generate an ECG signal, wherein the control unit is adapted to receive the ECG signal, and to initiate the applying of each burst after a delay following detection of a feature of the ECG. 
     
     
         87 . Apparatus for treating a subject, comprising:
 an electrode device, adapted to be coupled to tissue selected from the group consisting of: a vagus nerve and an epicardial fat pad of the subject};   a sensor, configured to detect a heart rate of the subject, and to generate a heart rate signal responsive thereto; and   a control unit comprising an integral feedback controller that has inputs comprising the detected heart rate and a target heart rate, the control unit adapted to:   drive the electrode device to apply a current to the tissue, and   configure the current responsive to an output of the integral feedback controller, so as to reduce the heart rate of the subject toward a target heart rate.   
     
     
         88 . The apparatus according to  claim 87 , wherein the control unit is adapted to drive the electrode device to apply the current in intermittent ones of a plurality of cardiac cycles of the subject. 
     
     
         89 . A method for treating a subject, comprising:
 detecting a heart rate of the subject; and   responsive to determining that the heart rate is greater than a threshold value, which threshold value is greater than a normal heart rate, applying a current to tissue selected from the group consisting of: a vagus nerve and an epicardial fat pad of the subject, and configuring the current so as to reduce the heart rate of the subject.   
     
     
         90 . The method according to  claim 89 , wherein configuring the current comprises configuring the current so as to reduce the heart rate towards a target heart rate. 
     
     
         91 . The method according to  claim 89 , wherein applying the current comprises applying the current in intermittent ones of a plurality of cardiac cycles of the subject. 
     
     
         92 . The method according to  claim 89 , wherein detecting the heart rate comprises:
 detecting a need for a treatment selected from the list consisting of: applying cardiac pacing to the subject and defibrillating the subject;   applying the treatment responsive to detecting the need for the treatment; and   withholding applying the current to the tissue when applying the treatment.   
     
     
         93 . The method according to  claim 89 , wherein applying the current comprises applying the current in respective pulse bursts in each of a plurality of cardiac cycles of the subject. 
     
     
         94 . The method according to  claim 93 , wherein applying the current comprises receiving an electrocardiographic signal, and initiating the applying of each burst after a delay following detection of a feature of the signal. 
     
     
         95 . A method for treating a subject, comprising:
 detecting a heart rate of the subject;   applying a current to tissue selected from the group consisting of: a vagus nerve and an epicardial fat pad of the subject; and   configuring the current so as to reduce the heart rate toward a target heart rate, responsive to an output of an integral feedback controller whose inputs comprise the detected heart rate and a target heart rate.   
     
     
         96 . A method for treating heart failure of a subject, comprising:
 designating a threshold heart rate above a normal heart rate of the subject;   detecting that the heart rate;   determining that the heart rate is greater than the threshold heart rate; and   responsive to the determining, applying a current to tissue comprising a vagus nerve and an epicardial fat pad of the subject respective pulse bursts in each of a plurality of cardiac cycles of the subject   
     
     
         97 . The method according to  claim 96 , wherein detecting the heart rate comprises:
 detecting a need for a treatment selected from the list consisting of: applying cardiac pacing to the subject and defibrillating the subject;   applying the treatment responsive to detecting the need for the treatment; and   withholding applying the current to the tissue when applying the treatment.   
     
     
         98 . The method according to  claim 96 , wherein applying the current comprises applying the current in intermittent ones of the plurality of cardiac cycles of the subject. 
     
     
         99 . Apparatus for applying current to a vagus nerve, comprising:
 a cathode, adapted to be disposed at a cathodic site of the vagus nerve and to apply a cathodic current to the vagus nerve so as to stimulate the vagus nerve;   a first anode, adapted to be disposed at a first anodal site of the vagus nerve; and   a second anode, directly electrically connected to the first anode, and adapted to be disposed at a second anodal site of the vagus nerve, such that the cathodic site is between the first anodal site and the second anodal site.   
     
     
         100 . A method for applying current to a vagus nerve, comprising:
 applying to the vagus nerve, through a common conductor, an anodal current at a first anodal site of the vagus nerve and at a second anodal site of the vagus nerve; and   applying a cathodic current to the vagus nerve at a cathodic site of the vagus nerve, so as to stimulate the vagus nerve, the cathodic site disposed between the first anodal site and the second anodal site.   
     
     
         101 . A treatment method, comprising:
 identifying that a subject suffers from a condition; and   treating the condition by:
 applying a current to tissue selected from the group consisting of: a vagus nerve and an epicardial fat pad of the subject, and 
 configuring the current to affect a behavior of an adrenergic system of the subject. 
   
     
     
         102 . The method according to  claim 101 , wherein identifying that the subject suffers from the condition comprises identifying that the subject suffers from a heart condition. 
     
     
         103 . The method according to  claim 101 , wherein configuring the current to affect the behavior of the adrenergic system comprises configuring the current to affect a behavior of an adrenal gland of the subject. 
     
     
         104 . The method according to  claim 101 , wherein configuring the current to affect the behavior of the adrenergic system comprises configuring the current to suppress the adrenergic system. 
     
     
         105 . A treatment method, comprising:
 identifying that a subject suffers from a heart condition; and   treating the heart condition by:
 applying a current to tissue selected from the group consisting of: a vagus nerve and an epicardial fat pad of the subject, and 
 configuring the current to modulate contractility of at least a portion of a heart of the subject. 
   
     
     
         106 . The method according to  claim 105 , wherein the heart condition is selected from the group consisting of: heart failure, and a heart arrhythmia, wherein identifying comprises identifying that the subject suffers from the selected condition, and wherein configuring the current comprises configuring the current to reduce the heart contractility. 
     
     
         107 . The method according to  claim 106 , wherein the condition includes atrial fibrillation, and wherein identifying comprises identifying that the subject suffers from the atrial fibrillation. 
     
     
         108 . A treatment method, comprising:
 identifying that a subject suffers from a heart condition; and   treating the heart condition by:
 applying a current to tissue selected from the group consisting of: a vagus nerve and an epicardial fat pad of the subject; and 
 configuring the current to increase coronary blood flow of the subject. 
   
     
     
         109 . A treatment method, comprising:
 identify that a subject suffers from a heart condition; and   treating the heart condition by applying, during each of a plurality of cardiac cycles of the subject, exactly one stimulating pulse to tissue selected from the group consisting of: a vagus nerve and an epicardial fat pad of the subject.