Cardiac pacing using adjustable atrio-ventricular delays

• US 6,351,673 B1
• Filed: 09/14/2000
• Issued: 02/26/2002
• Est. Priority Date: 05/08/1998
• Status: Expired due to Term

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Yu, Yinghong, Ding, Jiang, Kramer, Andrew P., Spinelli, Julio
• Primary Examiner(s): EVANISKO, GEORGE ROBERT
• Application Number:
  US09/661,608
• Time in Patent Office: 530 Days
• Field of Search: 607/9, 607/17, 607/23-25, 607/27
• US Class Current: 607/24
• 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: E21B 17/01 Risers

Abstract

A pacing system for providing optimal hemodynamic cardiac function for parameters such as contractility (peak left ventricle pressure change during systole or LV+dp/dt), or stroke volume (aortic pulse pressure) using system for calculating atrio-ventricular delays for optimal timing of a ventricular pacing pulse. The system providing an option for near optimal pacing of multiple hemodynamic parameters. The system deriving the proper timing using electrical or mechanical events having a predictable relationship with an optimal ventricular pacing timing signal.

Claims

1. A method, comprising:

selecting a cardiac reference event which repeats every cardiac cycle;

selecting a cardiac variable event which changes as a function of a cardiac performance parameter, the cardiac performance parameter related to optimal atrio-ventricular delay;

measuring an intrinsic time interval between the cardiac reference event and the cardiac variable event in an unpaced condition;

ascertaining an optimal atrio-ventricular delay for optimizing the cardiac performance parameter;

collecting intrinsic time intervals and optimal atrio-ventricular delays for a number of patients;

producing a mathematical relationship for the intrinsic time intervals and the optimal atrio-ventricular delays.

2. The method of claim 1, comprising generating pacing pulses using an estimated optimal atrio-ventricular delay produced from the mathematical relationship and a particular measured intrinsic time interval for a particular patient.

3. The method of claim 1, wherein the cardiac performance parameter is contractility.

4. The method of claim 1, wherein the cardiac performance parameter is maximum pulse pressure or stroke volume.

5. The method of claim 1, wherein the cardiac reference event is an electrical cardiac event.

6. The method of claim 1, wherein the cardiac reference event is a mechanical cardiac event.

7. The method of claim 1, wherein the cardiac variable event is an electrical cardiac event.

8. The method of claim 1, wherein the cardiac variable event is a mechanical cardiac event.

9. The method of claim 1, comprising:

ascertaining a second optimal atrio-ventricular delay for optimizing a second cardiac performance parameter;

collecting intrinsic time intervals and second optimal atrio-ventricular delays for a number of patients;

producing a second mathematical relationship for the intrinsic time intervals, the optimal atrio-ventricular delays and the second optimal atrio-ventricular delays.

10. The method of claim 9, wherein the second mathematical relationship results in an optimal atrio-ventricular delay for optimizing the cardiac performance parameter and the second cardiac performance parameter.

11. The method of claim 9, wherein the cardiac performance parameter is contractility and the second cardiac performance parameter is stroke volume.

12. The method of claim 11, wherein the mathematical relationship among a variable (AVD_cs) representing an atrio-ventricular delay for both contractility and stroke volume, a variable (PRm) representing a time interval measured from a right atrial sensing marker (P) to a right ventricular sensing marker (Rm), and constants (K3 and K4) is:

AVD_cs=K3 PRm−

K4 milliseconds.

13. The method of claim 12, wherein the mathematical relationship is:

AVD_cs=0.5 PRm−

15 milliseconds.

14. The method of claim 9, wherein the atrio-ventricular delay is switchable for a number of different optimal cardiac performance parameters and combinations of cardiac performance parameters.

15. A method, comprising:

selecting a cardiac reference event which repeats every cardiac cycle;

selecting a cardiac variable event which changes as a function of a cardiac performance parameter, the cardiac performance parameter related to optimal atrio-ventricular delay;

measuring an intrinsic time interval between the cardiac reference event and the cardiac variable event in an unpaced condition;

ascertaining an optimal atrio-ventricular delay for optimizing the cardiac performance parameter, including;

applying a pacing signal with varying atrio-ventricular delays while monitoring the cardiac performance parameter; and

determining an optimal atrio-ventricular delay for optimizing the cardiac performance parameter;

collecting intrinsic time intervals and optimal atrio-ventricular delays for a number of patients; and

producing a mathematical relationship for the intrinsic time intervals and the optimal atrio-ventricular delay pairs.

16. The method of claim 15, comprising generating pacing pulses using an estimated optimal atrio-ventricular delay produced from the mathematical relationship and a particular measured intrinsic time interval for a particular patient.

17. The method of claim 15, wherein the cardiac performance parameter is contractility.

18. The method of claim 15, wherein the cardiac performance parameter is maximum pulse pressure or stroke volume.

19. The method of claim 15, wherein the cardiac reference event is an electrical cardiac event.

20. The method of claim 15, wherein the cardiac reference event is a mechanical cardiac event.

21. The method of claim 15, wherein the cardiac variable event is an electrical cardiac event.

22. The method of claim 15, wherein the cardiac variable event is a mechanical cardiac event.

23. The method of claim 15, comprising:

ascertaining a second optimal atrio-ventricular delay for optimizing a second cardiac performance parameter;

collecting intrinsic time intervals and second optimal atrio-ventricular delays for a number of patients;

producing a second mathematical relationship for the intrinsic time intervals, the optimal atrio-ventricular delays and the second optimal atrio-ventricular delays.

24. The method of claim 23, wherein the second mathematical relationship results in an optimal atrio-ventricular delay for optimizing the cardiac performance parameter and the second cardiac performance parameter.

25. The method of claim 23, wherein the cardiac performance parameter is contractility and the second cardiac performance parameter is stroke volume.

26. The method of claim 25, wherein the mathematical relationship among a variable (AVD_cs) representing an atrio-ventricular delay for both contractility and stroke volume, a variable (PRm) representing a time interval measured from a right atrial sensing marker (P) to a right ventricular sensing marker (Rm), and constants (K3 and K4) is:

AVD_cs=K3 PRm−

K4 milliseconds.

27. The method of claim 26, wherein the mathematical relationship is:

AVD_cs=0.5 PRm−

15 milliseconds.

28. The method of claim 23, wherein the atrio-ventricular delay is switchable for a number of different optimal cardiac performance parameters and combinations of cardiac performance parameters.