Method and apparatus for detecting oscillations in cardiac rhythm with electrogram signals

• US 20050256542A1
• Filed: 07/19/2005
• Published: 11/17/2005
• Est. Priority Date: 03/26/2002
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Pastore, Joseph M., Girouard, Steven D., Zhu, Qingsheng, Ding, Jiang, KenKnight, Bruce H.
• Granted Patent: US 7,257,443 B2
• Time in Patent Office: Days
• US Class Current: 607/9
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/3684 for stimulating the heart at multiple sites of the ventricle or the atrium
• CPC Class Codes: A61N 1/36842 Multi-site stimulation in the same chamber
• CPC Class Codes: A61N 1/36843 Bi-ventricular stimulation

Abstract

A cardiac rhythm management device is configured to detect oscillations in cardiac rhythm by comparing electrogram signals during successive heart beats. Upon detection of electrical alternans, the device may adjust its operating behavior to compensate for the deleterious effects of the condition.

Claims

1. A cardiac rhythm management device, comprising:

a sensing channel for generating an electrogram waveform;

a controller programmed to extract a feature from the electrogram waveform during successive cardiac cycles and to detect electrical alternans by determining if a beat-to-beat oscillation above a specified threshold exists with respect to the extracted feature;

pacing channels configurable for delivering cardiac resynchronization therapy;

wherein the controller is programmed to either initiate or modify the delivery of cardiac resynchronization therapy if electrical alternans is detected.

2. The device of claim 1 wherein the extracted feature is an R-T interval.

3. The device of claim 1 wherein the extracted feature is a T-wave amplitude.

4. The device of claim 1 wherein the controller is programmed to deliver pacing therapy in accordance with a bradycardia mode, and further wherein the controller is programmed to decrease a programmed pacing rate when electrical alternans is detected.

5. The device of claim 1 wherein the controller is programmed to deliver anti-tachycardia pacing therapy when a measured heart rate exceeds a specified tachycardia threshold rate, and further wherein the controller is programmed to decrease the tachycardia threshold rate when electrical alternans is detected.

6. The device of claim 1 wherein the pacing channels are configurable for delivering atrial resynchronization pacing to both atria and further wherein the controller is programmed to either initiate or modify the delivery of atrial resynchronization therapy if electrical alternans is detected.

7. The device of claim 1 wherein the pacing channels are configurable for delivering ventricular resynchronization pacing to both ventricles and further wherein the controller is programmed to either initiate or modify the delivery of ventricular resynchronization therapy if electrical alternans is detected.

8. The device of claim 7 wherein the controller is programmed to adjust an atrio-ventricular delay interval for delivering ventricular resynchronization therapy if electrical alternans is detected.

9. The device of claim 7 wherein the controller is programmed to adjust a biventricular offset interval for delivering ventricular resynchronization therapy if electrical alternans is detected.

10. The device of claim 1 wherein the controller is programmed to reconfigure one or more pacing sites for delivering cardiac resynchronization therapy if electrical alternans is detected.

11. A method, comprising:

generating an electrogram waveform;

extracting a feature from the electrogram waveform during successive cardiac cycles and detecting electrical alternans by determining if a beat-to-beat oscillation above a specified threshold exists with respect to the extracted feature;

initiating or modifying delivery of cardiac resynchronization therapy if electrical alternans is detected.

12. The method of claim 11 wherein the extracted feature is an R-T interval.

13. The method of claim 11 wherein the extracted feature is a T-wave amplitude.

14. The method of claim 11 further comprising delivering pacing therapy in accordance with a bradycardia mode and decreasing a programmed pacing rate when electrical alternans is detected.

15. The method of claim 11 further comprising delivering anti-tachycardia pacing therapy when a measured heart rate exceeds a specified tachycardia threshold rate and decreasing the tachycardia threshold rate when electrical alternans is detected.

16. The method of claim 11 further comprising delivering atrial resynchronization pacing to both atria and either initiating or modifying the delivery of atrial resynchronization therapy if electrical alternans is detected.

17. The method of claim 11 further comprising delivering ventricular resynchronization pacing to both ventricles and either initiating or modifying the delivery of ventricular resynchronization therapy if electrical alternans is detected.

18. The method of claim 17 further comprising adjusting an atrio-ventricular delay interval for delivering ventricular resynchronization therapy if electrical alternans is detected.

19. The method of claim 17 further comprising adjusting a biventricular offset interval for delivering ventricular resynchronization therapy if electrical alternans is detected.

20. The method of claim 11 further comprising reconfiguring one or more pacing sites for delivering cardiac resynchronization therapy if electrical alternans is detected.