Cardiac pacing using adjustable atrio-ventricular delays

• US 20050131472A1
• Filed: 02/02/2005
• Published: 06/16/2005
• Est. Priority Date: 05/08/1998
• Status: Active Grant

• 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
• Granted Patent: US 7,856,270 B2
• Time in Patent Office: Days
• US Class Current: 607/9
• 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:

monitoring a signal representing ventricular electrical activity;

determining a ventricular electrical event, Z, which has an approximately constant timing relationship to delivery of ventricular pacing that maximizes peak positive ventricular pressure change; and

delivering a pacing pulse using a timing of event Z.

2. The method of claim 1, wherein the signal representing ventricular electrical activity comprises an electrogram recorded endocardially or epicardially from a ventricle.

3. The method of claim 1, wherein the signal representing ventricular electrical activity comprises a 12-lead surface ECG.

4. The method of claim 1, wherein event Z is a beginning of a QRS complex, Q*.

5. The method of claim 1, wherein event Z is a marker signal delivered by an external or implantable device.

6. A method, comprising:

monitoring a signal representing atrial mechanical activity;

determining an atrial mechanical event, X, which has an approximately constant timing relationship to a peak of atrial systole; and

delivering pacing pulse using the timing of event X.

7. A method, comprising:

delivering a ventricular pacing pulse with an optimal atrio-ventricular delay time interval (AVD_c) which is optimized to provide a maximum increase in LV+dp/dt (contractility) using a time interval, PY, between an atrial electrical event P and a ventricular mechanical event Y.

8. The method of claim 7, comprising:

determining the optimal AVD_c as a function of the time interval PY;

determining a model which approximates the optimal AVD_c to provide an estimated AVD_c; and

delivering a ventricular pacing pulse to a next (new) patient to maximize the LV+dp/dt (contractility) using the estimated AVD_c.

9. The method of claim 8, comprising:

performing a linear regression (best line fit) between the time interval PY and the optimal AVD_c; and

delivering a pacing signal using the estimated AVD_c which is provided by M1·

PY−

M2, where M1, and M2 are coefficients of the linear regression (best line fit).

10. The method of claim 9, wherein the ventricular pacing pulse is delivered to a left ventricle, wherein the time interval PY is measured from a right atrial sensing marker, P, to the beginning of intrinsic LV pressure development, Y, which corresponds to the beginning of LV systole, and wherein M1 is approximately kk, M2 is approximately qq milliseconds, and the best line fit for the estimated AVD_c is kk·

PY−

qq.

11. The method of claim 8, comprising:

measuring the time difference, n, between the time interval PY and the optimal AVD_c;

averaging the time difference n over a patient population; and

delivering a pacing signal using the estimated AVD_c which is provided by PY−

na, where na is the mean of the time difference n.

12. The method of claim 11, wherein the ventricular pacing pulse is delivered to a left ventricle, wherein the time interval PY is measured from a right atrial sensing marker, P, to the beginning of intrinsic LV pressure development, Y, which corresponds to the beginning of LV systole, and wherein na is approximately kk milliseconds, and the estimated AVD_c is PY−

kk.

13. A method, comprising:

filtering a signal representing ventricular electrical events to provide a filtered signal;

determining a portion of the filtered signal related to a Q-point; and

finding Q* at a position where a slope of the filtered signal related to Q-point is a predetermined ratio of the maximum slope of the filtered signal related to Q-point.

14. The method of claim 13, where the predetermined ratio is two (2) percent.

15. An apparatus, comprising:

a programmable pulse generator having a mechanical event sensor that monitors a signal representing ventricular mechanical activity and an electrical event sensor, wherein the programmable pulse generator calculates a time interval, PY, between an atrial electrical event P and the ventricular mechanical event Y and delivers a ventricular pacing pulse with an optimal atrio-ventricular delay time interval (AVD_c) which is optimized to provide a maximum increase in LV+dp/dt (contractility) using the time interval, PY.

16. The apparatus of claim 15, wherein the programmable pulse generator calculates AVD_c from a linear equation M1·

PY−

M2, where M1, and M2 are constants.

17. The apparatus of claim 16, wherein M1 is 0.96 and M2 is 139 milliseconds.

18. The apparatus of claim 15, wherein the programmable pulse generator measures the time interval PY from a right atrial sensing marker, P, to the beginning of intrinsic LV pressure development, Y, which corresponds to the beginning of LV systole, and delivers the ventricular pacing pulse to a left ventricle.

19. The apparatus of claim 15, wherein the programmable pulse generator calculates AVD_c from a linear equation PY−

na.

20. The apparatus of claim 19, wherein na is 150 milliseconds.

21. An apparatus, comprising:

a programmable pulse generator; and

at least one lead coupled to the programmable pulse generator, the at least one lead including at least one sensor adapted to sense a cardiac event,

wherein the programmable pulse generator is adapted to transmit pacing pulses using a delay time interval referenced to a first intrinsic cardiac event for enhancing systolic performance based on a first time interval between the first intrinsic cardiac event and a second intrinsic cardiac event that has an approximately constant timing relationship with respect to the first intrinsic cardiac event, the delay time interval including an atrio-ventricular delay (AVD_s) for optimizing stroke volume.

22. The apparatus of claim 21, wherein the at least one sensor includes a mechanical sensor adapted to sense mechanical events.

23. The apparatus of claim 22, wherein the AVD_S is determined using a model that maps a PX interval to the AVD_s, wherein the PX interval represents a time interval between an atrial electrical event (P) and a left atrial systole peak event (X).

24. The apparatus of claim 21, wherein the at least one sensor includes an electrical sensor adapted to sense electrical events.