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

• US 20080306568A1
• Filed: 08/05/2008
• Published: 12/11/2008
• Est. Priority Date: 03/30/2001
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Yu, Yinghong, Spinelli, Julio, Ding, Jing
• Granted Patent: US 8,280,512 B2
• Time in Patent Office: Days
• 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 module that stores information indicative of whether a wide QRS interval is present; and

a heart stimulation device, coupled to the module that stores information indicative of whether the wide QRS interval, between the beginning of the intrinsic ventricular depolarization and the ending of the intrinsic ventricular depolarization, is present, the heart stimulation device configured to set a paced atrio-ventricular delay to be substantially less than an intrinsic atrio-ventricular delay of the patient when the wide QRS interval is present.

2. The system of claim 1 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; and

wherein the module that stores information indicative of whether the wide QRS interval is present comprises 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 to determine when a wide interval is present.

3. The system of claim 2, 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 ventricular electrode.

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

5. The system of claim 1, wherein the wide interval is at least 175 milliseconds.

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

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

8. The system of claim 1, wherein the module that stores information indicative of whether a wide QRS interval is present is 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.

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

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

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

12. The system of claim 11, 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.

13. A system comprising:

means for storing information about whether a wide QRS interval, between the beginning of the intrinsic ventricular depolarization and the ending of the intrinsic ventricular depolarization, is present;

means for setting a paced atrio-ventricular delay to be substantially less than an intrinsic atrio-ventricular delay of the patient when the wide QRS interval is present.

14. The system of claim 13, comprising an electrode configured to be positioned in association with a left ventricle.

15. The system of claim 13, wherein the wide QRS interval is at least about 175 milliseconds.

16. The system of claim 13, wherein the paced atrio-ventricular delay is set to about one-half of the intrinsic atrio-ventricular delay of the patient when the wide QRS interval is present.

17. A method comprising:

obtaining information about whether a wide QRS interval, between a beginning of an intrinsic ventricular depolarization and an ending of the intrinsic ventricular depolarization, is present in a patient; and

setting a paced atrio-ventricular delay of the patient to be substantially less than an intrinsic atrio-ventricular delay of the patient when the wide QRS interval is present in the patient.

18. The method of claim 17, comprising:

detecting a beginning of an intrinsic ventricular depolarization and an ending of the intrinsic ventricular depolarization using an implantable medical device;

computing an interval between the beginning of the intrinsic ventricular depolarization and the ending of the intrinsic ventricular depolarization; and

setting a paced atrio-ventricular delay of the patient to substantially less than an intrinsic atrio-ventricular delay of the patient using information about the interval between the beginning of the intrinsic ventricular depolarization and the ending of the intrinsic ventricular depolarization.

19. The method of claim 18, wherein the detecting the beginning of the intrinsic ventricular depolarization and the ending of the intrinsic ventricular depolarization includes using information obtained from an electrical signal received from a left ventricular electrode.

20. The method of claim 17, comprising declaring a wide QRS interval to be present when the QRS interval exceeds at least 175 milliseconds.