Closed loop neural stimulation synchronized to cardiac cycles

Abstract

Various aspects of the present subject matter relate to a method. According to various method embodiments, cardiac activity is detected, and neural stimulation is synchronized with a reference event in the detected cardiac activity. Neural stimulation is titrated based on a detected response to the neural stimulation. Other aspects and embodiments are provided herein.

1 . (canceled) 
     
     
         2 . A system, comprising:
 an implantable medical device (IMD) configured for subcutaneous implantation, the implantable medical device including a housing, electrodes on the housing, neural stimulation circuitry within the housing, and a controller within the housing, wherein the IMD is configured to use the electrodes on the housing to sense cardiac activity and the controller is configured to use the sensed cardiac activity to control the neural stimulation circuitry.   
     
     
         3 . The system of  claim 2 , wherein the electrodes on the housing include ECG electrodes for use to subcutaneously sense ECG signals 
     
     
         4 . The system of  claim 2 , wherein the controller is configured to titrate neural stimulation using the sensed cardiac activity. 
     
     
         5 . The system of  claim 4 , wherein the controller is configured to detect heart rate variability (HRV) using the sensed cardiac activity and to titrate neural stimulation using the detected HRV. 
     
     
         6 . The system of  claim 2 , wherein the controller is configured to detect heart rate turbulence (HRT) using the sensed cardiac activity and to titrate neural stimulation using the detected HRT. 
     
     
         7 . The system of  claim 2 , wherein the controller is configured to detect a PR interval using the sensed cardiac activity and to titrate neural stimulation using the detected PR interval. 
     
     
         8 . The system of  claim 2 , wherein the controller is configured to detect T-wave velocity using the sensed cardiac activity and to titrate neural stimulation using the detected T-wave velocity. 
     
     
         9 . The system of  claim 2 , wherein the controller is configured to detect an action potential duration, and to titrate neural stimulation using the detected action potential duration. 
     
     
         10 . The system of  claim 2 , wherein the controller is configured to identify reference events in the sensed cardiac activity, and use the reference events to control neural stimulation timing. 
     
     
         11 . The system of  claim 10 , wherein the reference events are indicative of cardiac cycles. 
     
     
         12 . The system of  claim 10 , wherein the reference events are P waves. 
     
     
         13 . A system, comprising:
 an implantable medical device (IMD) configured for subcutaneous implantation, the implantable medical device including a housing, ECG electrodes on the housing for use to subcutaneously sense ECG signals, neural stimulation circuitry within the housing, myocardial stimulation circuitry within the housing, and a controller within the housing, wherein the IMD is configured to use the electrodes on the housing to sense cardiac activity and the controller is configured to use the sensed cardiac activity to control the neural stimulation circuitry and to control the myocardial stimulation circuitry.   
     
     
         14 . The system of  claim 13 , wherein the myocardial stimulation circuitry includes bradycardia pacing circuitry, and the controller is configured to use the sensed cardiac activity to control the bradycardia pacing circuitry. 
     
     
         15 . The system of  claim 13 , wherein the myocardial stimulation circuitry includes cardioversion or defibrillation circuitry and the controller is configured to use the sensed cardiac activity to control the cardioversion or defibrillation circuitry. 
     
     
         16 . The system of  claim 13 , wherein the myocardial stimulation circuitry includes anti-tachycardia pacing circuitry and the controller is configured to use the sensed cardiac activity to control the cardioversion or defibrillation circuitry. 
     
     
         17 . The system of  claim 13 , wherein the myocardial stimulation circuitry includes cardiac resynchronization pacing circuitry and the controller is configured to use the sensed cardiac activity to control the cardiac resynchronization circuitry. 
     
     
         18 . The system of  claim 13 , wherein the controller is configured to titrate neural stimulation using the sensed cardiac activity. 
     
     
         19 . The system of  claim 18 , wherein the controller is configured to use the sensed cardiac activity to detect heart rate, detect heart rate variability (HRV), detect heart rate turbulence (HRT), detect a PR interval, detect T-wave velocity or detect an action potential duration. 
     
     
         20 . The system of  claim 13 , wherein the controller is configured to identify reference events in the sensed cardiac activity, and use the reference events to control neural stimulation timing. 
     
     
         21 . The system of  claim 20 , wherein the reference events are indicative of cardiac cycles.