System and method for determining optimal atrioventricular delay based on intrinsic conduction delays

• US 20060047319A1
• Filed: 08/27/2004
• Published: 03/02/2006
• Est. Priority Date: 08/27/2004
• Status: Active Grant

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Inventors: Min, Xiaoyi, Park, Euljoon, Levine, Paul A., Bruhns, Ken
• Granted Patent: US 7,248,925 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

Abstract

Techniques are provided for estimating optimal atrioventricular delay values for use in pacing the ventricles. Both the intrinsic inter-atrial conduction delay and the intrinsic atrioventricular conduction delay are determined for the patient and then the preferred atrioventricular pacing delay is derived therefrom. By taking into account intrinsic inter-atrial delay along with intrinsic atrioventricular delay, it is believed that a more reliable estimate of the true optimal atrioventricular delay values for the patient can be achieved than with techniques that only take into account intrinsic atrioventricular delay values. In one example, the technique uses intracardiac electrogram (IEGM) signals and surface electrocardiogram (EKG) signals and hence can be performed by an external programmer without requiring Doppler echocardiography or other cardiac performance monitoring techniques. In another example, wherein the implanted device is equipped with a coronary sinus lead, the technique uses only IEGM signals and hence can be performed by the device itself.

Claims

1. A method for determining an atrioventricular delay value for use in delivering cardiac pacing therapy to the heart of a patient in which an implantable cardiac stimulation device is implanted, the method comprising:

determining an inter-atrial conduction delay for the patient;

determining an intrinsic atrioventricular conduction delay for the patient; and

determining an atrioventricular delay value for use in pacing based on the inter-atrial conduction delay and the intrinsic atrioventricular conduction delay.

2. The method of claim 1 further comprising delivering pacing therapy using the implantable cardiac stimulation device subject to the atrioventricular delay value.

3. The method of claim 1 wherein the atrioventricular delay value comprises a AS-VP delay for use in pacing the ventricles subsequent to an intrinsic atrial depolarization and a AP-VP delay value for use in pacing the ventricles subsequent to an atrial pacing pulse.

4. The method of claim 1 wherein determining the inter-atrial conduction delay for the patient comprises:

determining a width of an electrical atrial event; and

deriving the inter-atrial conduction delay from the width of the atrial event.

5. The method of claim 4 wherein determining the width of the atrial event comprises:

inputting an atrial intracardiac electrogram (A-IEGM) signal derived from a lead implanted within the atria of the patient;

inputting a surface electrocardiogram (EKG) signal derived from leads mounted externally on the patient;

determining a value representative of the duration of an atrial event detected within the A-IEGM signal; and

adjusting the value based on a comparison of the A-IEGM signal and the EKG signal.

6. The method of claim 4 wherein the atrial event is representative of an intrinsic atrial depolarization.

7. The method of claim 4 wherein the atrial event is representative of an atrial evoked response.

8. The method of claim 1 wherein determining the intrinsic atrioventricular conduction delay for the patient comprises:

measuring an intrinsic conduction delay following an atrial electrical event propagating from the atria to the left ventricle (A-VS_L);

measuring an intrinsic conduction delay following the atrial electrical event propagating from the atria to the right ventricle (A-VS_R); and

evaluating the intrinsic atrioventricular delay based on a comparison of A-VS_L and A-VS_R.

9. The method of claim 8 wherein evaluating the intrinsic A-VS delay based on a comparison of A-VS_L and A-VS_R is performed by selecting the shorter of the A-VS_L and A-VS_R values.

10. The method of claim 1 wherein determining the atrioventricular delay value based on the inter-atrial conduction delay and the intrinsic atrioventricular conduction delay comprises:

determining a first candidate delay value (AS-VP₁) based on the inter-atrial conduction delay in combination with the intrinsic atrioventricular delay derived from sensed atrial events;

determining a second candidate delay value (AS-VP₂) based on the inter-atrial conduction delay derived from sensed atrial events; and

evaluating a AS-VP delay based on a comparison of AS-VP₁ and AS-VP₂.

11. The method of claim 10 wherein evaluating the AS-VP delay based on a comparison of AS-VP₁ and AS-VP₂ is performed by selecting among:

AS-VP₁, AS-VP₂, and the shorter of the AS-VP₁ and AS-VP₂ values.

12. The method of claim 1 wherein determining atrioventricular pacing delay values based on the inter-atrial conduction delay and the intrinsic atrioventricular conduction delay comprises:

determining a first candidate delay value (AP-VP₁) based on the inter-atrial conduction delay in combination with the intrinsic atrioventricular delay derived from paced atrial events;

determining a second candidate delay value (AP-VP₂) based on the inter-atrial conduction delay derived from paced atrial events; and

evaluating a AP-VP delay based on a comparison of AP-VP₁ and AP-VP₂.

13. The method of claim 1 wherein determining the atrioventricular delay value is performed by an external programmer based on IEGM signals received from the implantable device and surface EKG signals received from a surface EKG device.

14. The method of claim 13 further comprising transmitting the atrioventricular delay value to the implantable device for use therein.

15. The method of claim 1 wherein determining the atrioventricular delay value is performed by the implanted device based on IEGM signals.

16. The method of claim 1 further comprising adjusting the atrioventricular delay value based on current patient heart rate.

17. The method of claim 16 wherein adjusting the atrioventricular delay value based on patient heart rate is performed by applying a scaling factor (β

) to a AS-VP delay value wherein the scaling factor is based on current heart rate and a rest rate.

18. The method of claim 1 wherein determining an inter-atrial conduction delay for the patient comprises detecting the end of at least one atrial event in an A-IEGM signal by:

detecting the onset of the atrial event in the A-IEGM signal;

opening a detection window within the A-IEGM signal;

setting positive and negative threshold values;

identifying a last point in time within the detection window at which the A-IEGM signal falls outside the threshold values; and

identifying the last point in time as being the end of the atrial event.

19. A system for use in delivering cardiac pacing therapy to the heart of a patient in which an implantable cardiac stimulation device is implanted, the system comprising:

means for determining an inter-atrial conduction delay for the patient;

means for determining an intrinsic atrioventricular conduction delay for the patient;

means for determining a atrioventricular delay value for use in pacing based on the inter-atrial conduction delay and the intrinsic atrioventricular conduction delay; and

means for pacing the ventricles of the patient using the atrioventricular delay value.

20. A system for determining an atrioventricular delay value for use in delivering cardiac pacing therapy to the heart of a patient in which an implantable cardiac stimulation device is implanted, the system comprising:

a telemetry unit operative to receive atrial and ventricular intracardiac electrogram (IEGM signals) from the implanted device;

a surface electrocardiogram (EKG) input unit operative to receive surface EKG signals; and

a programmer-based atrioventricular delay optimization system operative to determine an inter-atrial conduction delay for the patient based on a comparison of atrial IEGM signals and surface EKG signals, determine an intrinsic atrioventricular conduction delay for the patient based on the atrial and ventricular IEGM signals, and to then determine an atrioventricular pacing delay value based on the inter-atrial conduction delay and the intrinsic atrioventricular conduction delay.

21. A method comprising:

determining a value related to a duration of right and left atrial activity;

determining an intrinsic atrioventricular conduction delay; and

determining an atrioventricular delay value for use in pacing based on the value and the intrinsic atrioventricular conduction delay.

22. The method of claim 21 wherein the atrioventricular delay value comprises a AS-VP delay for use in pacing the ventricles subsequent to an intrinsic atrial depolarization and a AP-VP delay value for use in pacing the ventricles subsequent to an atrial pacing pulse.

23. The method of claim 21 wherein determining the value related to duration of the right and left atrial activity comprises:

determining a width of an electrical atrial event; and

deriving an inter-atrial conduction delay from the width of the atrial event.

24. The method of claim 21 wherein determining the atrioventricular delay value is performed by an external programmer based on IEGM signals received from an implantable device and surface EKG signals received from a surface EKG device.