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

• US 20030105492A1
• Filed: 12/05/2001
• Published: 06/05/2003
• 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.
• Granted Patent: US 6,768,923 B2
• Time in Patent Office: Days
• 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 the depolarizations of the heart;

a processor receiving data from the sensor, wherein the processor identifies an early electrical event from the data; and

a pulse generator configured to provide a pacing stimulus to at least one ventricle in timed relation to the identified 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. A device, as in claim 9, wherein the processor identifies the Q* event using template matching.

11. An apparatus, as in claim 10, wherein the template matching comprises:

calculating an ensemble-averaged waveform;

establishing a Q* for the ensemble averaged waveform;

establishing a template; and

matching a real time electrogram with the template to identify a real time Q*.

12. The device as in claim 1 wherein the sensor senses an electrogram waveform and the processor is programmed to ensemble-average a digitized electrogram waveform over a predetermined number of QRS complexes in the digitized electrogram waveform.

13. The device of claim 12 wherein the processor is further programmed to compute a time of occurrence of the Q* event from further processing of the ensemble-average of the digitized electrogram waveform.

14. The device of claim 13 wherein the further processing includes 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 threshold as a mean plus standard deviation of the flattest segment.

15. The device as in claim 14 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.

16. A cardiac rhythm management device comprising:

(a) means for detecting depolarization signals propagating along the HIS bundle; and

(b) means for providing a pacing stimulus to the heart in timed relation to a detected depolarization signal propagating along the HIS bundle

17. A cardiac rhythm management device, comprising:

a means for detecting the depolarization of the ventricles;

a means for identifying an onset of the depolarization (Q* event); and

a means for providing a pacing stimulus to the heart in timed relation to the identified Q* event.

18. A method for triggered ventricular pacing, comprising:

sensing the depolarization of one of the ventricles and the HIS bundle;

identifying an early electrical event in a sensed depolarization waveform; and

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

19. A method as in claim 18 wherein sensing the depolarizations of the ventricles uses a method selected from a group consisting of:

an epicardial electrogram;

an endocardial electrogram;

or

a surface electrocardiogram.

20. A method as in claim 18 wherein an onset of ventricular depolarization (Q*) is identified.

21. A method as in claim 20 wherein identifying the Q* event uses template matching.

22. The method as in claim 21 wherein the template matching comprises:

calculating an ensemble-averaged waveform;

establishing a Q* point on the ensemble averaged waveform;

establishing a template; and

matching a real time electrogram with the template to identify a real time Q* point.

23. A method as in claim 18 wherein triggering occurs immediately upon identifying the early electrical event.

24. A method as in claim 18 wherein triggering occurs within between 1 and 50 milliseconds of identifying the early electrical event.

25. A method as in claim 19 wherein sensing the depolarizations of the HIS bundle comprises a HIS bundle electrogram.

26. A method as in claim 25 wherein a depolarization of the HIS bundle is identified.

27. A method as in claim 18 wherein triggering occurs immediately upon the identification of a depolarization of the HIS bundle.

28. A method as in claim 18, wherein triggering occurs within between 1 and 50 ms of identifying a depolarization of the HIS bundle.