Atrial pacing therapy for treating mitral regurgitation

1. A method comprising:

identifying a regurgitant mitral or tricuspid valve in a patient;

implanting a cardiac rhythm management device in the patient for delivering pacing therapy to the heart through one or more pacing electrodes;

delivering ventricular pacing therapy and pacing therapy in a manner which excites an atrium during ventricular systole, referred to as secondary atrial pacing;

delivering the secondary atrial pacing with timing based upon ventricular events such that a secondary atrial pace is delivered at a secondary ventricular-atrio interval subsequent to a ventricular pace or sense; and,

delivering left ventricular pacing therapy based upon right ventricular senses, wherein a secondary ventricular-atrio interval of one specified duration is initiated by a left ventricular pace while a secondary ventricular-atrio interval of another duration is triggered by a right ventricular sense.

2. The method of claim 1 wherein the ventricular pacing therapy is delivered as biventricular pacing.

3. The method of claim 1 wherein the secondary atrial pacing is delivered at multiple atrial pacing sites.

4. The method of claim 1 further comprising measuring trans-thoracic impedance to derive a measurement reflective of cardiac stroke volume.

5. The method of claim 4 further comprising modulating the frequency of the secondary atrial pacing in accordance with measured cardiac stroke volume.

6. The method of claim 4 further comprising modulating the duration of the secondary atrial pacing in accordance with measured cardiac stroke volume.

7. The method of claim 1 further comprising initiating a protective period following an atrial sense or pace during which an atrial secondary pace is inhibited.

8. The method of claim 1 further comprising providing a trans-thoracic impedance sensor for providing a measurement reflective of cardiac stroke volume.

9. The method of claim 8 further comprising modulating the frequency of the secondary atrial pacing in accordance with measured cardiac stroke volume.

10. The method of claim 8 further comprising modulating the duration of the secondary atrial pacing in accordance with measured cardiac stroke volume.

11. An implantable cardiac device, comprising:

pulse generating circuitry coupled to one or more electrodes and configured to deliver pacing pulses to a cardiac chamber;

sensing circuitry coupled to one or more electrodes and configured to detect electrical activity from a cardiac chamber;

a controller coupled to the pulse generating and sensing circuitry and configured to control the delivery of pacing pulses;

wherein the controller is programmed to delivering pacing therapy in a manner which excites an atrium during ventricular systole, referred to as secondary atrial pacing;

wherein the controller is programed to deliver ventricular pacing and to deliver the secondary atrial pacing with timing based upon ventricular events such that a secondary atrial pace is delivered at a secondary ventricular-atrio interval subsequent to a ventricular sense or pace; and,

wherein the controller is programmed to deliver left ventricular pacing therapy based upon right ventricular senses, wherein a secondary ventricular-atrio interval of one specified duration is initiated by a left ventricular pace while a secondary ventricular-atrio interval of another duration is triggered by a right ventricular sense.

12. The device of claim 11 wherein the ventricular pacing therapy is delivered as biventricular pacing.

13. The device of claim 11 wherein the controller is programmed to deliver the secondary atrial pacing at multiple atrial pacing sites.

14. The device of claim 11 wherein the controller is programmed to initiate a protective period following an atrial sense or pace during which an atrial secondary pace is inhibited.