Apparatus and method for ventricular pacing triggered by detection of early ventricular excitation

• US 6,768,923 B2
• Filed: 12/05/2001
• Issued: 07/27/2004
• Est. Priority Date: 12/05/2001
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Spinelli, Julio C., Ding, Jiang, Kramer, Andrew P.
• Primary Examiner(s): Schaetzle, Kennedy
• Application Number:
  US10/004,695
• Publication Number:
  US 20030105492A1
• Time in Patent Office: 965 Days
• Field of Search: 607/9, 600/509, 600/521
• US Class Current: 607/9
• CPC Class Codes: A61N 1/365 controlled by a physiological parameter, e.g. heart potential evoked response A61N1/371

Abstract

A pacing apparatus and method for providing optimum timing for ventricular pacing without referencing atrial activities. The pacing apparatus includes a processor, at least one sensor and a pulse generator. The pacing method includes the sensing of ventricular depolarization and the identification of an early electrical event, such as a depolarization of the HIS bundle or an onset of a ventricular depolarization (Q*). The system derives the proper timing using this early electrical event which provides a predictable relationship with an optimal ventricular pacing signal.

Claims

1. A cardiac rhythm management device, comprising:

at least one sensor configured to sense an electrogram waveform representative of the depolarization of the heart;

a processor receiving data from the sensor, wherein the processor is programmed to ensemble-average a digitized electrogram waveform over a predetermined number of QRS complexes and to derive therefrom the time of occurrence of an early electrical event (Q*) from the data by calculation of an absolute derivative of the ensemble-averaged electrogram waveform and normalizing the absolute derivative using a maximum absolute derivative of the ensemble-averaged electrogram waveform and locating a flattest segment of the normalized derivative of the absolute derivative of the ensemble-averaged electrogram within a window of a predetermined length to establish a threshold as a mean plus standard deviation of the flattest segment; and

a pulse generator configured to provide a pacing stimulus to at least one ventricle in timed relation to the Q* event.

2. The device, as in claim 1, wherein the sensor is configured for placement in sensing proximity to a HIS bundle.

3. A device, as in claim 1, wherein the sensor is configured for placement in one or both ventricles.

4. A device, as in claim 1, wherein the sensor is configured to record an electrocardiogram.

5. A device, as in claim 4, wherein the sensor is configured to record a HIS bundle electrogram.

6. A device, as in claim 5, wherein the processor identifies the onset of HIS bundle depolarization.

7. A device, as in claim 6, wherein the processor identifies the onset of HIS bundle depolarization using template matching.

8. A device, as in claim 4, wherein the sensor is configured to record one of an epicardial electrogram and an endocardial electrogram.

9. A device, as in claim 8, wherein the sensor is configured to record the onset point (Q*) of an electrogram.

10. The device as in claim 1 wherein the Q* event is defined as the first data point in the normalized derivative of the ensemble-averaged electrogram waveform after which there are no more than a predetermined number of consecutive data points whose derivative values fall below said threshold.

11. A method for effecting CRT of AF patients, comprising:

sensing the depolarization of one of the ventricles;

identifying an early electrical event (Q*) in a sensed ventricular depolarization waveform by a template matching algorithm including the steps of;

(i) calculating an ensemble-averaged waveform;

(ii) establishing a Q* point on the ensemble averaged waveform;

(iii) establishing a template; and

(iv) matching a real time electrogram with the template to identify a real time Q* point; and

triggering a pacing stimulus to one or both ventricles in timed relation to the identified event.

12. A method as in claim 11 wherein triggering occurs immediately upon the identification of a depolarization of the HIS bundle.

13. A method as in claim 11, wherein triggering occurs within between 1 and 50 ms of identifying a depolarization of the HIS bundle.