Method and apparatus for predicting recurring ventricular arrhythmias

• US 20030191403A1
• Filed: 04/05/2002
• Published: 10/09/2003
• Est. Priority Date: 04/05/2002
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Sharma, Vinod, Zhou, Xiaohong, Olson, Walter H.
• Granted Patent: US 6,922,585 B2
• Time in Patent Office: Days
• US Class Current: 600/515
• CPC Class Codes: A61B 5/361 Detecting fibrillation
• CPC Class Codes: A61B 5/363 Detecting tachycardia or bradycardia
• CPC Class Codes: A61B 5/4035 Evaluating the autonomic nervous system
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/3962 in combination with another heart therapy
• CPC Class Codes: A61N 1/39622 Pacing therapy

Abstract

An implantable medical device and method are provided for assessing autonomic tone and risk factors associated with arrhythmias and, based on this assessment, an early recurrence of ventricular tachycardia or ventricular fibrillation is predicted. Specifically, changes in R-R interval, heart rate variability, patient activity, and myocardial ischemia are measured prior to and after a detected an arrhythmia episode. A recurrence score is calculated as a weighted sum of measured parameters and compared to a prediction criterion. The prediction criterion may be a preset threshold score or an individualized episode template based on previously calculated recurrence scores associated with recurring episodes. Stored parameters and episode-related data may be downloaded for offline analyses for optimizing prediction criteria and monitoring patient status.

Claims

1. A method for predicting a recurring arrhythmia comprising:

detecting an arrhythmia episode;

measuring a number of parameters based on said arrhythmia episode indicative of autonomic tone;

calculating a recurrence score based on the measured parameters; and

predicting an arrhythmia event with high probabilistic certainty based on said recurrence score.

2. The method of claim 1 wherein said method of detecting includes measuring R-R intervals and P-P intervals.

3. The method of claim 1 wherein said method of measuring includes collecting R-R interval templates.

4. The method of claim 1 wherein said method includes collecting a heart rate variability (HRV) template.

5. The method of claim 1 wherein said method includes collecting an activity template.

6. The method according to claim 5 wherein a correlation between a physical activity and an R-R interval is included in said activity template.

7. The method of claim 1 wherein said collecting method includes determining indicators of autonomic tone and risk factors for VT and VF recurrence.

8. The method of claim 1 wherein said method of predicting includes comparing said recurrence score with a threshold, a VT or VF episode.

9. The method of claim 1 wherein said method of predicting includes using a range of value benchmarks to predict VT or VF episodes if the recurrence score falls within said range of value benchmarks.

10. A processor-implemented software system for providing predictive scores associated with arrhythmic episodes comprising:

means for storing episode data;

means for collecting autonomic assessment data;

means for calculating a recurrence score;

means for determining if said recurrence score meets a prediction criteria;

means for detecting recurring episodes; and

means for establishing episode template;

said means for storing, said means for collecting, said means for calculating, said means for determining, said means for detecting, and said means for establishing being coordinated to operate in logical relations thereof.

11. The software system of claim 10 wherein said means for storing episode data is in data and logic communication with means for detecting termination of delivery of therapies.

12. The software system of claim 10 wherein said means for collecting autonomic assessment data is in data and logic communication with said means for calculating.

13. The software system of claim 10 wherein said means for determining if said recurrence score meets a prediction criteria includes means for marking if a threshold is exceeded.

14. The software system of claim 13 wherein said means for determining if said recurrence score meets a prediction criteria includes means for setting a range of values to compare with said recurrence score.