AV nodal stimulation during atrial tachyarrhythmia to prevent inappropriate therapy delivery

Patent metadata

Field	Value
Publication number	US-9433791-B2
Application number	US-201113105689-A
Country	US
Kind code	B2
Filing date	May 11, 2011
Priority date	May 11, 2011
Publication date	Sep 6, 2016
Grant date	Sep 6, 2016

Abstract

The disclosure describes techniques for delivering electrical stimulation to decrease the ventricular rate response during an atrial tachyarrhythmia, such as atrial fibrillation. AV nodal stimulation is employed during an atrial tachyarrhythmia episode with rapid ventricular conduction to distinguish ventricular tachyarrhythmia from supraventricular tachycardia and thereby prevent delivering inappropriate therapy to a patient.

First claim

The invention claimed is:

1. A method comprising:
incrementing a counter upon detection of a ventricular tachyarrhythmia event;
detecting an atrial tachyarrhythmia;
during the detected atrial tachyarrhythmia, anticipating detection of a ventricular tachyarrhythmia in a heart of a patient based on a ventricular tachyarrhythmia not yet being detected but the counter reaching a threshold value of a ventricular tachyarrhythmia event count;
in response to anticipating detection of the ventricular tachyarrhythmia, delivering electrical stimulation to block the atrioventricular node of the heart; and
terminating the delivery of electrical stimulation based on one or more stimulation termination criteria.

2. The method of claim 1 , further comprising establishing a stimulation time period wherein the electrical stimulation is delivered, the established stimulation time period based on a sense time period over which ventricular depolarizations can be sensed between one or more pulse of the electrical stimulation,
the established stimulation time period being bounded by limits that prevent an accumulation of blanking periods applied to a sensing amplifier that would exceed the sense time period.

3. The method of claim 2 , further comprising determining the sense time period based on an R-R interval of the heart of the patient.

4. The method of claim 3 , wherein determining the sense time period based on an R-R interval of the heart of the patient comprises:
measuring a plurality of R-R intervals for the heart of the patient;
calculating a median R-R interval from the measured R-R intervals; and
setting the sense time period to greater than or equal to a predetermined portion of the median R-R interval.

5. The method of claim 2 , further comprising delivering electrical stimulation to block the atrioventricular node of the heart regardless of the sense time period, before delivering electrical stimulation based on the sensed time period.

6. The method of claim 5 , wherein electrical stimulation is delivered regardless of the sense time period for a stimulation response time period.

7. The method of claim 1 , wherein the one or more stimulation termination criteria comprises at least one of expiration of an electrical stimulation delivery time period, an accumulation of blanking time periods exceeding a threshold percentage of an electrical stimulation delivery time period, failure to detect a threshold ventricular rate response within an electrical stimulation response time period, or detection of a ventricular tachyarrhythmia.

8. The method of claim 7 , wherein the threshold percentage of an electrical stimulation delivery time period comprises less than or equal to approximately 50% a sense time period.

9. The method of claim 1 , further comprising delivering the electrical stimulation via electrodes positioned in the right atrium.

10. The method of claim 1 , wherein anticipating detection of a ventricular tachyarrhythmia in a heart of a patient based on a ventricular tachyarrhythmia not yet being detected but the counter reaching a threshold value of a ventricular tachyarrhythmia event count comprises anticipating detection, in response to detection of the atrial tachyarrhythmia, of a ventricular tachyarrhythmia in a heart of a patient based on a ventricular tachyarrhythmia not yet being detected but the counter reaching a threshold value of a ventricular tachyarrhythmia event count.

11. A method comprising:
incrementing a counter upon detection of a ventricular tachyarrhythmia event;
anticipating detection of a ventricular tachyarrhythmia in a heart of a patient based on a ventricular tachyarrhythmia not yet being detected but the counter reaching a threshold value of a ventricular tachyarrhythmia event count;
determining a sense time period; and
in response to anticipating detection of the ventricular tachyarrhythmia, delivering electrical stimulation to block the atrioventricular node of the heart over an electrical stimulation delivery time period, wherein the electrical stimulation delivery time period is based on the sense time period over which ventricular depolarizations can be sensed during the electrical stimulation delivery time period, the stimulation time period being bounded by limits that prevent an accumulation of blanking periods applied to a sensing amplifier that would exceed the sense time period.

12. The method of claim 11 , further comprising detecting an atrial tachyarrhythmia comprising at least one of atrial fibrillation or atrial tachycardia.

13. The method of claim 12 , wherein detecting an atrial tachyarrhythmia comprises:
detecting a P-P interval value for the heart of the patient that is less than a percentage threshold of an R-R interval value; and
analyzing a rhythm of the heart of the patient for indications of sinus tachycardia.

14. The method of claim 11 , wherein anticipating detection of a ventricular tachyarrhythmia is based at least on a threshold value of a ventricular tachyarrhythmia event count.

15. The method of claim 14 , wherein the ventricular tachyarrhythmia event count comprises a number of sensed ventricular intervals indicative of a ventricular tachyarrhythmia.

16. The method of claim 11 , wherein delivering electrical stimulation comprises delivering the electrical stimulation during a refractory period of the heart of the patient.

17. The method of claim 11 further comprising confirming, prior to delivering electrical stimulation, that a median R-R interval for the heart of the patient is less than a maximum threshold ventricular contraction rate and greater than or equal to a minimum threshold ventricular contraction rate.

18. The method of claim 11 , further comprising determining the sense time period based on an R-R interval of the heart of the patient.

19. The method of claim 18 , wherein determining the sense time period based on an R-R interval of the heart of the patient comprises:
measuring a plurality of R-R intervals for the heart of the patient;
calculating a median R-R interval from the measured R-R intervals; and
setting the sense time period to greater than or equal to a predetermined portion of the median R-R interval.

20. The method of claim 11 , further comprising delivering electrical stimulation to block the atrioventricular node of the heart regardless of the sense time period, before delivering electrical stimulation based on the sensed time period.

21. The method of claim 20 , wherein electrical stimulation is delivered regardless of the sense time period for a stimulation response time period.

22. The method of claim 21 , wherein the stimulation response time period is equal to approximately 10 seconds.

23. The method of claim 21 , wherein the stimulation response time period is equal to a time required for the heart of the patient to beat in a range from approximately 5 to approximately 10 beats.

24. The method of claim 21 , wherein the stimulation response time period is equal to a time required for an approximately 20% reduction in the rate at which the heart of the patient contracts from a contraction rate of the heart when electrical stimulation delivered regardless of when the sense time period begins.

25. The method of claim 21 , wherein the stimulation response time period is equal to a time required for a 40 beats per minute (bpm) reduction in the rate at which the heart of the patient contracts when a contraction rate of t

Assignees

• Warman Eduardo N
• Burnes John E
• Michels Koen J
• Ziegler Paul D
• Kornet Lilian
• Medtronic Inc

Inventors

• Warman Eduardo N
• Burnes John E
• Michels Koen J
• Ziegler Paul D
• Kornet Lilian

Classifications

• A61N1/3624

  occurring in the atrium, i.e. atrial tachycardia · CPC title

• A61N1/3622 Primary

  comprising two or more electrodes co-operating with different heart regions · CPC title

• A61N1/36114

  Cardiac control, e.g. by vagal stimulation (stimulating the heart A61N1/362) · CPC title

• A61N1/3621

  for treating or preventing abnormally high heart rate · CPC title

• A61N1/36053

  adapted for vagal stimulation (A61N1/36114 takes precedence) · CPC title