Identifying heart failure patients suitable for resynchronization therapy using QRS complex width from an intracardiac electrogram

• US 7,424,324 B2
• Filed: 05/20/2005
• Issued: 09/09/2008
• Est. Priority Date: 03/30/2001
• Status: Expired due to Fees

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Yu, Yinghong, Ding, Jiang, Spinelli, Julio
• Primary Examiner(s): BOCKELMAN, MARK
• Application Number:
  US11/133,526
• Publication Number:
  US 20050216065A1
• Time in Patent Office: 1,208 Days
• Field of Search: 600/509, 600/516, 607/9, 607/25, 607/27
• US Class Current: 607/27
• CPC Class Codes: A61B 2034/2072 Reference field transducer attached to an instrument or patient
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/366 Detecting abnormal QRS complex, e.g. widening
• 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 1/36592 controlled by the heart rate variability
• CPC Class Codes: A61N 1/3682 with a variable atrioventricular delay

Abstract

Methods and systems are disclosed for determining whether a patient is a responder to cardiac resynchronization therapy. The beginning and ending of the intrinsic ventricular depolarization are determined through signals measured from one or more electrodes implanted in the patient'"'"'s heart. An interval between the beginning and ending of the intrinsic ventricular depolarization is computed and is compared to a threshold. The threshold may be determined empirically. The pacing parameters of a heart stimulation device, such as a pacemaker, may then be configured, for example, by setting the paced atrio-ventricular delay based on whether the patient responds positively to cardiac resynchronization therapy.

Claims

1. A system comprising:

a detection module communicatively linked to a ventricular electrode, wherein the detection module detects a beginning of an intrinsic ventricular depolarization and an ending of the intrinsic ventricular depolarization;

a processing module communicatively linked to the detection module, wherein the processing module computes an interval between the beginning of the intrinsic ventricular depolarization and the ending of the intrinsic ventricular depolarization, compares the interval to a threshold, and determines whether a patient is a responder to resynchronization therapy using the interval; and

wherein the detection module and processing module are included in or coupled to a heart stimulation device that is electrically connected to the electrode, and wherein when the interval is greater than the threshold, the heart stimulation device sets a paced atrio-ventricular delay to substantially less than an intrinsic atrio-ventricular delay of the patient when the patient is determined to be a responder to resynchronization therapy.

2. The system of claim 1, wherein the detection module detects the beginning of the intrinsic ventricular depolarization and the ending of the intrinsic ventricular depolarization from an electrical signal received from the electrode.

3. The system of claim 1, wherein the electrode is configured to be positioned within a left ventricle.

4. The system of claim 1, wherein the threshold is 175 milliseconds.

5. The system of claim 1, wherein the paced atric-ventricular delay is set to one-half of the intrinsic atrio-ventricular delay of the patient.

6. The system of claim 1, wherein when the interval is less than the threshold, the heart stimulation device sets the paced atrio-ventricular delay to approximately 30 milliseconds less than the intrinsic atrio-ventricular delay.

7. The system of claim 1, wherein the detection module and processing module are contained in a device programmer that is in communication with a heart stimulation device that is electrically connected to the electrode, and wherein the device programmer sends an instruction to the heart stimulation device to set the paced atrio-ventricular delay of the heart stimulation device.

8. The system of claim 1, wherein the processing module statistically analyzes multiple intervals detected from multiple intrinsic ventricular depolarizations.

9. The system of claim 8, wherein the statistical analysis involves calculating a median of the multiple intervals.

10. The system of claim 1, wherein the beginning of the ventricular depolarization is Q* and the ending of the ventricular depolarization is S*.

11. The system of claim 10, wherein Q* is computed by smoothing a depolarization signal and finding a point in time in a cardiac cycle prior to an R wave peak where a value of the smoothed depolarization first exceeds a baseline standard deviation value computed from the smoothed waveform and wherein S* is computed by finding a point in time after the R wave peak where a value of the smoothed depolarization last exceeds the baseline standard deviation value.

12. The system of claim 1, wherein the detection module and the processing module are contained in an implantable device.

13. The system of claim 1, wherein the detection module detects the beginning and ending of the ventricular depolarization and the processing module computes the interval and compares the interval to a threshold periodically other than for each cardiac cycle.

14. A system comprising:

means for detecting a beginning of an intrinsic ventricular depolarization and an ending of the intrinsic ventricular depolarization, wherein the means for detecting detects the beginning of the intrinsic ventricular depolarization and the ending of the intrinsic ventricular depolarization from an electrical signal received from an electrode configured to be positioned at a ventricle;

means for computing an interval between the beginning of the intrinsic ventricular depolarization and the ending of the intrinsic ventricular depolarization, comparing the interval to a threshold, and determining whether a patient is a responder to resynchronization therapy using the interval; and

wherein the means for detecting and the means for computing and for comparing are included in or coupled to a heart stimulation device that is electrically connected to the electrode, and wherein when the interval is greater than the threshold, the heart stimulation device sets a paced atrio-ventricular delay to substantially less than an intrinsic atrio-ventricular delay of the patient when the patient is determined to be a responder to resynchronization therapy.

15. The system of claim 14, wherein the electrode is configured to be positioned within a left ventricle.

16. The system of claim 14, wherein the threshold is 175 milliseconds.

17. The system of claim 14, wherein the paced atrio-ventricular delay is set to one-half of the intrinsic atrio-ventricular delay of the patient.

18. The system of claim 14, wherein when the interval is less than the threshold, the heart stimulation device sets the paced atrio-ventricular delay to equal to approximately 30 milliseconds less than the intrinsic atrio-ventricular delay of the patient.

19. The system of claim 14, wherein the means for detecting and the means for computing and for comparing are contained in a device programmer that is in communication with a heart stimulation device, and wherein the device programmer sends an instruction to the heart stimulation device to set the paced atrio-ventricular delay of the heart stimulation device.

20. The system of claim 14, wherein the means for computing and for comparing computes the interval by statistically analyzing multiple intervals detected from multiple intrinsic ventricular depolarizations.

21. The system of claim 20, wherein the means for computing and for comparing statistically analyzes multiple intervals by calculating a median.

22. The system of claim 14, wherein the beginning of the ventricular depolarization is Q* and the ending of the ventricular depolarization is S*.

23. The system of claim 22, wherein Q* is computed by smoothing a depolarization signal and finding a point in time in a cardiac cycle prior to an R wave peak where a value of the smoothed depolarization signal first exceeds a baseline standard deviation value computed from the smoothed depolarization signal and wherein S* is computed by finding a point in time after the R wave peak where a value of the smoothed depolarization signal last exceeds the baseline standard deviation value.

24. The system of claim 14, wherein the means for detecting and the means for computing and comparing are contained in an implantable device.

25. The system of claim 14, wherein the means for detecting detects the beginning and ending of the ventricular depolarization and the means for computing and comparing computes the interval and compares the interval Q a threshold periodically other than for each cardiac cycle.