Method and apparatus for preventing cardiac arrhythmias with endovascular stimulation
Certain cardiac arrhythmias can be prevented by appropriate electrical stimulation of autonomic nerves innervating the heart. An implantable cardiac rhythm management device is configured to deliver such stimulation when an autonomic imbalance is predicted to be present via an endovascular electrode. Autonomic imbalance may be predicted to be present based upon circadian rhythms, detected heart rates, or detected heart rate variability.
1. An implantable cardiac rhythm management device, comprising:
a ventricular sensing channel;
an autonomic stimulation channel including a pulse generator and a stimulation electrode adapted for endovascular disposition adjacent sympathetic nerves innervating the head;
a controller programmed to predict the presence of an autonomic imbalance due to increased parasympathetic activity by measurement of heart rate via the ventricular sensing channel; and,
wherein the controller is further programmed to cause the delivery of autonomic stimulation pulses for stimulating sympathetic nerves when an autonomic imbalance reflecting increased parasympathetic activity is predicted to be present.
2. The device of claim 1 wherein the autonomic stimulation channel includes a bipolar stimulation electrode incorporated into a lead adapted for intravenous insertion.
3. The device of claim 1 further comprising a cardioversion/defibrillation shocking channel that includes a shock pulse generator and a shock lead, and wherein the autonomic stimulation channel includes a bipolar stimulation electrode incorporated into the shock lead.
4. The device of claim 1 wherein the pulse generator delivers autonomic stimulation in the form of a pulse train.
5. The device of claim 4 wherein the pulse train is at a frequency of between 5 and 50 Hz.
6. The device of claim 1 wherein the controller is programmed to monitor heart rate via the ventricular sensing channel and to detect increased parasympathetic activity based on the time intervals between successive ventricular senses.
7. The device of claim 6 wherein increased parasympathetic activity is detected based on an average of RR intervals taken over a specified period of time.
8. The device of claim 1 wherein the controller is programmed to monitor heart rate via the ventricular sensing channel and to detect increased parasympathetic activity based upon the variability of the measured heart rate.
9. The device of claim 1 wherein the controller is programmed to deliver sympathetic stimulation at periodic time intervals when increased parasympathetic activity is predicted to be present based upon circadian rhythms.