Cardiac resynchronization via left ventricular pacing

• US 20040215249A1
• Filed: 04/23/2003
• Published: 10/28/2004
• Est. Priority Date: 04/23/2003
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Corbucci, Giorgio
• Granted Patent: US 7,558,626 B2
• Time in Patent Office: Days
• US Class Current: 607/9
• CPC Class Codes: A61B 5/366 Detecting abnormal QRS complex, e.g. widening
• CPC Class Codes: A61B 5/4836 Diagnosis combined with treatment in closed-loop systems or methods A61B5/0036 takes precedence
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• 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 1/3682 with a variable atrioventricular delay

Abstract

The invention is directed to techniques for providing cardiac resynchronization therapy by synchronizing delivery of pacing pulses to the left ventricle with intrinsic right ventricular depolarizations. An implantable medical device measures an interval between an atrial depolarization and an intrinsic ventricular depolarization is measured. In various embodiments, the intrinsic ventricular depolarization may be an intrinsic right or left ventricular depolarization. The implantable medical device delivers pacing pulses to the left ventricle to test a plurality of pacing intervals. The pacing intervals tested may be within a range around the measured interval between the atrial depolarization and the intrinsic ventricular depolarization. One of the pacing intervals is selected based on a measured characteristic of an electrogram that indicates ventricular synchrony. For example, the pacing interval may be selected based on measured QRS complex widths and/or Q-T intervals. The implantable medical device paces the left ventricle based on the selected pacing interval.

Claims

1. An implantable medical device to provide cardiac resynchronization therapy, the device comprising:

electrodes to detect electrical signals within a heart and deliver pacing pulses to the heart; and

a processor to measure an interval between an atrial depolarization and an intrinsic ventricular depolarization based on the detected signals, control delivery of pacing pulses to a left ventricle of the heart via the electrodes at pacing intervals determined based on the measured interval, and select one of the pacing intervals based on an electrogram signal representing the signals detected by the electrodes.

2. The implantable medical device of claim 1, wherein the processor measures a intervals between atrial depolarizations and intrinsic ventricular depolarizations, determines an average of the measured intervals, and controls delivery of the pacing pulses at the pacing intervals based on the average interval.

3. The implantable medical device of claim 1, wherein the pacing intervals are greater than a first pacing interval that is less than the interval between the atrial depolarization and the intrinsic ventricular depolarization and less than a second pacing interval that is greater than the interval between the atrial depolarization and the intrinsic ventricular depolarization.

4. The implantable medical device of claim 1, wherein the processor measures a plurality of QRS complex widths within the electrogram signal, each of the QRS complex widths corresponding to a respective one of the delivered pacing pulses, and selects one of the pacing intervals that corresponds to a smallest one of the QRS widths.

5. The implantable medical device of claim 1, wherein the processor measures a plurality of Q-T intervals within the electrogram signal, each of the Q-T intervals corresponding to a respective one of the delivered pacing pulses, and selects one of the pacing intervals that corresponds to a largest one of the Q-T intervals.

6. The implantable medical device of claim 1, wherein the processor measures a plurality of QRS complex widths and a plurality of Q-T intervals within the electrogram signal, each of the QRS complex widths and each of the Q-T intervals corresponding to a respective one of the delivered pacing pulses, identifies a first one of the pacing intervals that corresponds to a smallest one of the QRS complex widths, identifies a second one of the pacing intervals that corresponds to a largest one of the Q-T intervals, and determines an average of the first and second pacing intervals, and wherein the selected pacing interval is the average of the first and second pacing intervals.

7. The implantable medical device of claim 1, wherein the processor controls delivery of pacing pulses to the left ventricle via the electrodes based on the selected pacing interval.

8. The implantable medical device of claim 7, wherein the processor determines a difference between the selected pacing interval and the interval between the atrial depolarization and the intrinsic ventricular depolarization, and controls delivery of pacing pulses to the left ventricle based on the difference.

9. The implantable medical device of claim 8, wherein the intrinsic ventricular depolarization is an intrinsic right ventricular depolarization, the difference is substantially zero, and the processor controls delivery of a pacing pulse to the left ventricle upon detection of a subsequent intrinsic right ventricular depolarization.

10. The implantable medical device of claim 8, wherein the intrinsic ventricular depolarization is an intrinsic right ventricular depolarization, the difference is greater than zero, and the processor controls delivery of a pacing pulse to the left ventricle at a time that is the difference after detection of a subsequent intrinsic right ventricular depolarization.

11. The implantable medical device of claim 8, wherein the intrinsic ventricular depolarization is a right ventricular depolarization, the difference is less than zero, and the processor periodically determines a current interval between an atrial depolarization and an intrinsic right ventricular depolarization, determines a current pacing interval that is the difference less than the current interval between the atrial depolarization and the intrinsic right ventricular depolarization, and controls delivery of a pacing pulse to the left ventricle the current pacing interval after detection of a subsequent atrial depolarization.

12. The implantable medical device of claim 8, wherein the intrinsic ventricular depolarization is an intrinsic left ventricular depolarization, and the processor periodically determines a current interval between an atrial depolarization and an intrinsic left ventricular depolarization, determines a current pacing interval based on the difference and the current interval between the atrial depolarization and the intrinsic left ventricular depolarization, and controls delivery of a pacing pulse to the left ventricle the current pacing interval after detection of a subsequent atrial depolarization.

13. The implantable medical device of claim 1, wherein the electrodes comprise a first bipolar electrode pair located proximate to the left ventricle and a second bipolar electrode pair located within an atrium of the heart.

14. The implantable medical device of claim 13, wherein the electrodes further comprises a third bipolar electrode pair located within a right ventricle of the heart.

15. The implantable medical device of claim 1, wherein the device is implanted within the patient.

16. A method for providing cardiac resynchronization therapy comprising:

measuring an interval between an atrial depolarization and an intrinsic ventricular depolarization;

delivering pacing pulses to a left ventricle of a heart at pacing intervals determined based on the interval between the atrial depolarization and the intrinsic ventricular depolarization; and

selecting one of the pacing intervals based on a detected electrogram signal representing signals within the heart.

17. The method of claim 16, wherein measuring an interval between an atrial depolarization and an intrinsic ventricular depolarization comprises:

measuring intervals between atrial depolarizations and intrinsic ventricular depolarizations; and

determining an average of the measured intervals, and

wherein delivering pacing pulses comprises delivering pacing pulses at pacing intervals determined based on the average interval.

18. The method of claim 16, wherein the pacing intervals are greater a first pacing interval that is less than the interval between the atrial depolarization and the intrinsic ventricular depolarization and less than a second pacing interval that is greater than the interval between the atrial depolarization and the intrinsic ventricular depolarization.

19. The method of claim 16, wherein measuring a characteristic of an electrogram comprises measuring a plurality of QRS complex widths, each of the QRS complex widths corresponding to a respective one of the delivered pacing pulses, and

wherein selecting one of the pacing intervals comprises selecting one of the pacing intervals that corresponds to a smallest one of the QRS widths.

20. The method of claim 16, wherein measuring a characteristic of an electrogram comprises measuring a plurality of Q-T intervals, each of the Q-T intervals corresponding to a respective one of the delivered pacing pulses, and

wherein selecting one of the pacing intervals comprises selecting one of the pacing intervals that corresponds to a largest one of the Q-T intervals.

21. The method of claim 16, wherein measuring a characteristic of an electrogram comprises measuring a plurality of QRS complex widths and a plurality of Q-T intervals, each of the QRS complex widths and each of the Q-T intervals corresponding to a respective one of the delivered pacing pulses, and

wherein selecting one of the pacing intervals comprises:

identifying a first one of the pacing intervals that corresponds to a smallest one of the QRS complex widths;

identifying a second one of the pacing intervals that corresponds to a largest one of the Q-T intervals; and

determining an average of the first and second pacing intervals.

22. The method of claim 16, further comprising delivering pacing pulses to the left ventricle based on the selected pacing interval.

23. The method of claim 22, wherein delivering pacing pulses to the left ventricle comprises:

determining a difference between the selected pacing interval and the interval between the atrial depolarization and the intrinsic ventricular depolarization; and

delivering pacing pulses to the left ventricle based on the difference.

24. The method of claim 23, wherein the intrinsic ventricular depolarization is an intrinsic right ventricular depolarization, the difference is zero, and delivering pacing pulses to the left ventricle based on the difference comprises delivering a pacing pulse to the left ventricle upon detection of a subsequent intrinsic right ventricular depolarization.

25. The method of claim 23, wherein the intrinsic ventricular depolarization is an intrinsic right ventricular depolarization, the difference is greater than zero, and delivering pacing pulses to the left ventricle based on the difference comprises delivering a pacing pulse to the left ventricle at a time that is the difference after detection of a subsequent intrinsic right ventricular depolarization.

26. The method of claim 23, wherein the intrinsic ventricular depolarization is a right ventricular depolarization, the difference is less than zero, and delivering pacing pulses to the left ventricle based on the difference comprises:

periodically determining a current interval between an atrial depolarization and an intrinsic right ventricular depolarization;

determining a current pacing interval that is the difference less than the current interval between the atrial depolarization and the intrinsic right ventricular depolarization; and

delivering a pacing pulse to the left ventricle the current pacing interval after detection of a subsequent atrial depolarization.

27. The method of claim 23, wherein the intrinsic ventricular depolarization is an intrinsic left ventricular depolarization, and delivering pacing pulses to the left ventricle based on the difference comprises:

periodically determining a current interval between an atrial depolarization and an intrinsic left ventricular depolarization;

determining a current pacing interval based on the difference and the current interval between the atrial depolarization and the intrinsic left ventricular depolarization; and

delivering a pacing pulse to the left ventricle the current pacing interval after detection of a subsequent atrial depolarization.

28. A computer-readable medium comprising instructions that cause a processor to:

measure an interval between an atrial depolarization and an intrinsic ventricular depolarization;

control delivery of pacing pulses to a left ventricle of a heart at pacing intervals determined based on the measured interval; and

select one of the pacing intervals based on an electrogram signal representing the signals detected by the electrodes.

29. The computer-readable medium of claim 28, wherein the instructions that cause a processor to measure an interval between an atrial depolarization and an intrinsic ventricular depolarization comprise instructions that cause a processor to:

measure a plurality of intervals between atrial depolarizations and intrinsic ventricular depolarizations; and

determine an average of the measured intervals, and

wherein the instructions that cause a processor to control delivery of pacing pulses comprise instructions that cause a processor to control delivery of pacing pulses at pacing intervals determined based on the average interval.

30. The computer-readable medium of claim 28, wherein the pacing intervals are greater than a first pacing interval that is less than the interval between the atrial depolarization and the intrinsic ventricular depolarization and less than a second pacing interval that is greater than the interval between the atrial depolarization and the intrinsic ventricular depolarization.

31. The computer-readable medium of claim 28, wherein the instructions that cause a processor to measure a characteristic of an electrogram comprise instructions that cause a processor to measure a plurality of QRS complex widths within the electrogram, each of the QRS complex widths corresponding to a respective one of the delivered pacing pulses, and

wherein the instructions that cause a processor to select one of the pacing intervals comprise instructions that cause a processor to select one of the pacing intervals-that corresponds to a smallest one of the QRS widths.

32. The computer-readable medium of claim 28, wherein he instructions that cause a processor to measure a characteristic of an electrogram comprises instructions that cause a processor to measure a plurality of Q-T intervals within the electrogram, each of the Q-T intervals corresponding to a respective one of the delivered pacing pulses, and

wherein the instructions that cause a processor to select one of the pacing intervals comprise instructions that cause a processor to select one of the pacing intervals that corresponds to a largest one of the Q-T intervals.

33. The computer-readable medium of claim 28, wherein instructions that cause a processor to measure a characteristic of an electrogram comprise instructions that cause a processor to measure a plurality of QRS complex widths and a plurality of Q-T intervals within the electrogram, each of the QRS complex widths and each of the Q-T intervals corresponding to a respective one of the delivered pacing pulses, and

wherein the instructions that cause a processor to select one of the pacing intervals comprise instructions that cause a processor to:

identify a first one of the pacing intervals that corresponds to a smallest one of the QRS complex widths;

identify a second one of the pacing intervals that corresponds to a largest one of the Q-T intervals; and

determine an average of the first and second pacing intervals.

34. The computer-readable medium of claim 28, further comprising instructions that cause a processor to control delivery of pacing pulses to the left ventricle based on the selected pacing interval.

35. The computer-readable medium of claim 34, wherein the instructions that cause a processor to control delivery of pacing pulses to the left ventricle based on the selected pacing interval comprise instructions that cause a processor to:

determine a difference between the selected pacing interval and the interval between the atrial depolarization and the intrinsic ventricular depolarization; and

control delivery of pacing pulses to the left ventricle based on the difference.

36. The computer-readable medium of claim 35, wherein the intrinsic ventricular depolarization is an intrinsic right ventricular depolarization, the difference is zero, and the instructions that cause a processor to control delivery of pacing pulses to the left ventricle based on the difference comprise instructions that cause a processor to control delivery of a pacing pulse to the left ventricle upon detection of a subsequent intrinsic right ventricular depolarization.

37. The computer-readable medium of claim 35, wherein the intrinsic ventricular depolarization is an intrinsic right ventricular depolarization, the difference is greater than zero, and the instructions that cause a processor to control delivery of pacing pulses to the left ventricle based on the difference comprise instructions that cause a processor to control delivery of a pacing pulse to the left ventricle the difference after detection of a subsequent intrinsic right ventricular depolarization.

38. The computer-readable medium of claim 35, wherein the intrinsic ventricular depolarization is a right ventricular depolarization, the difference is less than zero, and the instructions that cause a processor to control delivery of pacing pulses to the left ventricle based on the difference comprise instructions that cause a processor to:

periodically determine a current interval between an atrial depolarization and an intrinsic right ventricular depolarization;

determine a current pacing interval that is the difference less than the current interval between the atrial depolarization and the intrinsic right ventricular depolarization; and

control delivery of a pacing pulse to the left ventricle the current pacing interval after detection of a subsequent atrial depolarization.

39. The computer-readable medium of claim 35, wherein the intrinsic ventricular depolarization is an intrinsic left ventricular depolarization, and that instructions that cause a processor to control delivery of pacing pulses to the left ventricle based on the difference comprise instructions that cause a processor to:

periodically determine a current interval between an atrial depolarization and an intrinsic left ventricular depolarization;

determine a current pacing interval based on the difference and the current interval between the atrial depolarization and the intrinsic left ventricular depolarization; and

control delivery of a pacing pulse to the left ventricle the current pacing interval after detection of a subsequent atrial depolarization.