Method and Apparatus to Ensure Consistent Left Ventricular Pacing

• US 20090281590A1
• Filed: 05/05/2009
• Published: 11/12/2009
• Est. Priority Date: 05/07/2008
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Maskara, Barun, Brooke, M. Jason, Ding, Jiang
• Granted Patent: US 8,676,314 B2
• Time in Patent Office: Days
• US Class Current: 607/25
• 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
• 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
• CPC Class Codes: A61N 1/371 Capture, i.e. successful stimulation

Abstract

A method of operating a cardiac therapy system to deliver cardiac resynchronization therapy (CRT) pacing that includes pacing both ventricles or pacing only the left ventricle is described. Delivery of the CRT pacing to one or both ventricles is scheduled for a cardiac cycle. If an intrinsic depolarization of a ventricle is detected during a pacing delay of the ventricle, then the scheduled CRT pacing to the ventricle is inhibited for the cycle. The intrinsic interval of the ventricle, such as the intrinsic atrioventricular interval concluded by the intrinsic depolarization, is measured. During a subsequent cardiac cycle, the pacing delay of the ventricle is decreased to be less than or equal to the measured intrinsic interval. Capture of the ventricle is verified after pacing is delivered during the subsequent cardiac cycle.

Claims

1. A method of operating a cardiac therapy system to deliver cardiac resynchronization therapy (CRT) pacing that includes pacing at least a left ventricle, the method comprising:

scheduling delivery of the CRT pacing to one or both ventricles for a cardiac cycle;

if an intrinsic depolarization of a ventricle is detected during a pacing delay of the ventricle;

inhibiting the scheduled CRT pacing to the ventricle for the cardiac cycle;

measuring an intrinsic interval of the ventricle for the cardiac cycle;

decreasing a subsequent pacing delay of the ventricle for a subsequent cardiac cycle to be less than or equal to the measured intrinsic interval; and

determining if capture of the ventricle occurs for the subsequent cardiac cycle.

2. The method of claim 1, wherein the pacing delay comprises one or more of a right atrioventricular delay, a left atrioventricular delay, and an interventricular delay.

3. The method of claim 1, further comprising increasing the pacing delay of the ventricle by a predetermined amount during one or more additional cardiac cycles following the subsequent cardiac cycle.

4. The method of claim 1, wherein:

scheduling the CRT pacing comprises scheduling the CRT pacing to both left and right ventricles;

inhibiting the scheduled CRT pacing to the ventricle comprises inhibiting the scheduled CRT pacing to one or both of the left and right ventricles;

measuring the intrinsic interval of the ventricle comprises measuring intrinsic intervals of one or both of the left and right ventricles; and

decreasing the subsequent pacing delay of the ventricle comprises decreasing subsequent pacing delays of one or both of the left and right ventricles.

5. The method of claim 1, further comprising:

if no intrinsic depolarization of the ventricle is detected during the pacing delay;

delivering the CRT pacing to the ventricle as scheduled;

determining a cardiac response to the pacing; and

adjusting the pacing delay of the ventricle for the subsequent cardiac cycle based on the cardiac response to the delivered CRT pacing.

6. The method of claim 5, wherein determining the cardiac pacing response comprises discriminating between capture, fusion, and non-capture of the ventricle.

7. The method of claim 5, wherein adjusting the pacing delay based on the cardiac pacing response comprises maintaining or increasing the pacing delay if capture is determined as the pacing response.

8. The method of claim 5, wherein adjusting the pacing delay based on the cardiac pacing response comprises incrementally decreasing the pacing delay if fusion is determined as the pacing response.

9. The method of claim 5, further comprising:

measuring cardiac rate; and

adjusting the pacing delay based on the measured cardiac rate.

10. The method of claim 9, wherein adjusting the pacing delay based on the cardiac pacing response and cardiac rate comprises adjusting the pacing delay based on a look-up table indexed by cardiac rate.

11. The method of claim 9, further comprising adjusting one or more pacing energy parameters if the cardiac response is determined to be non-capture.

12. A method of setting pacing delays for cardiac resynchronization therapy (CRT) pacing that includes at least pacing the left ventricle, the method comprising:

scheduling delivery of the CRT pacing for a cardiac cycle;

measuring cardiac rate for the cardiac cycle;

if an intrinsic depolarization of at least one ventricle is detected during the pacing delay of the at least one ventricle;

inhibiting the scheduled CRT pacing to the ventricle; and

measuring an intrinsic interval of the ventricle that is concluded by the intrinsic ventricular depolarization;

if no intrinsic depolarization of the ventricle is detected during the pacing delay of the ventricle, determining a cardiac response to the CRT pacing, including discriminating between capture, fusion, and non-capture of the ventricle;

storing information related to the measured cardiac rate, the measured intrinsic interval, and the cardiac pacing response for a plurality of cardiac intervals; and

presenting information to a clinician indicating relationships between the measured cardiac rate and the cardiac pacing response for the plurality of cardiac intervals.

13. The method of claim 12, further comprising:

analyzing the stored information to determine at least one recommended pacing delay based on one or more of the measured cardiac rate, the measured intrinsic interval; and

the cardiac pacing response for the plurality of cardiac intervals; and

presenting the at least one recommended pacing delay to the clinician via a user interface.

14. The method of claim 13, further comprising analyzing the stored information to determine a look up table of recommended pacing delays based on the measured cardiac rate, the measured intrinsic interval;

and the cardiac pacing response for the plurality of cardiac intervals.

15. A cardiac therapy system capable of delivering cardiac resynchronization therapy (CRT) that includes pacing at least the left ventricle, the system comprising:

electrodes configured to electrically couple to right and left ventricles;

sensing circuitry configured to sense cardiac signals via the electrodes, the cardiac signals including intrinsic depolarization signals;

pacing circuitry configured to generate pacing pulses deliverable through the electrodes;

cardiac response classification circuitry configured to determine cardiac responses to the pacing pulses; and

pacing control circuitry configured to control the pacing circuitry, the pacing control circuitry configured to schedule delivery of CRT pacing to at least one ventricle relative to a pacing delay for the ventricle during a cardiac cycle, and, if an intrinsic depolarization is detected during the pacing delay, to inhibit the scheduled CRT pacing to the ventricle, to measure an intrinsic interval of the ventricle, and to decrease a subsequent pacing delay of the ventricle for a subsequent cardiac cycle to be less than or equal to the measured intrinsic interval.

16. The cardiac therapy system of claim 15, wherein the pacing control circuitry is configured to further decrease the pacing delay for additional cardiac cycles until the cardiac response classification circuitry determines that capture occurs.

17. The cardiac therapy system of claim 15, wherein the pacing control circuitry is further configured to deliver the CRT pacing if an intrinsic depolarization of the ventricle is not detected during the pacing delay of the cardiac cycle, and to adjust a subsequent pacing delay of a subsequent cardiac cycle based on the cardiac pacing response of the ventricle to the delivered CRT pacing.

18. The cardiac therapy system of claim 15, further comprising a memory, configured to store information including measured cardiac rate, measured intrinsic intervals of the at least one ventricle, and cardiac pacing responses of the ventricle for a plurality of cardiac cycles, wherein the pacing control circuitry is configured to analyze the stored information to determine pacing delays for the ventricle, the analysis taking into account the measured cardiac rate, the measured intrinsic intervals, and the cardiac pacing responses of the ventricle for the plurality of cardiac cycles.

19. The cardiac therapy system of claim 18, wherein the pacing control circuitry is configured to develop a look-up table of pacing delays for the ventricle based on the analysis.

20. The cardiac therapy system of claim 18, wherein the pacing control circuitry is configured to increase the pacing delay of the ventricle by a predetermined amount during one or more additional cardiac cycles following the subsequent cardiac cycle.

21. The cardiac therapy system of claim 15, wherein the pacing control circuitry is configured to schedule the CRT pacing to both left and right ventricles, to inhibit the scheduled pace to one or both of the left and right ventricles, to measure the intrinsic intervals of one or both of the left and right ventricles, and to decrease subsequent pacing delays of one or both of the left and right ventricles.

22. The cardiac therapy system of claim 15, wherein:

the pacing control circuitry and pacing circuitry are configured to cooperate to deliver the scheduled CRT pacing if no intrinsic depolarization of the ventricle is detected during the pacing delay; and

the cardiac response classification processor is configured to determine the cardiac pacing response to the delivered pacing including discriminating between capture, fusion, and non-capture of the ventricle, wherein the pacing control circuitry is configured to adjust the pacing delay of the ventricle for the subsequent cardiac cycle based on the cardiac pacing response.

23. The cardiac therapy system of claim 22, wherein the pacing control circuitry is configured to maintain or increase the pacing delay if capture is determined as the pacing response.

24. The cardiac therapy system of claim 22, wherein the pacing control circuitry is configured to decrease the pacing delay if fusion is determined as the pacing response.

25. The cardiac therapy system of claim 22, wherein the pacing control circuitry is configured to measure cardiac rate and to adjust the pacing delay based on the measured intrinsic interval, the cardiac pacing response, and the measured cardiac rate.

26. The cardiac therapy system of claim 22, further comprising

a memory configured to store information related to the measured cardiac rate, the measured intrinsic interval, and the cardiac pacing response for a plurality of cardiac intervals;

and

an external device configured to present to a clinician information indicating relationships between the measured cardiac rate, the measured intrinsic interval, and the cardiac pacing response for the plurality of cardiac intervals.

27. The cardiac therapy system of claim 26, wherein:

the pacing control circuitry is configured to analyze the stored information to determine at least one recommended pacing delay for a subsequent cardiac cycle based on the pacing delay, the measured cardiac rate, the measured intrinsic interval; and

the cardiac pacing response for the plurality of cardiac intervals; and

the external device is configured to present the at least one recommended pacing delay to a human analyst via a user interface.

28. The cardiac therapy system of claim 27, wherein the at least one recommended pacing delay comprises one or more of right atrioventricular delay, a left atrioventricular delay and an interventricular delay.

29. The cardiac therapy system of claim 26 wherein the pacing control circuitry is configured to analyze the stored information to configure a look up table of recommended pacing delays based on previous pacing delays, the measured cardiac rate, the measured intrinsic interval;

and the cardiac pacing response for the plurality of cardiac intervals.

30. The cardiac therapy system of claim 15, further comprising a sensor configured to generate an output based a patient'"'"'s hemodynamic need, wherein the pacing control circuitry is further configured to adjust the pacing delay based on the sensor output.