Method and apparatus for synchronization of atrial defibrillation pulses

• US RE36,765 E
• Filed: 04/01/1997
• Issued: 07/04/2000
• Est. Priority Date: 11/02/1993
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Mehra, Rahul
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): SCHAETZLE, KENNEDY
• Application Number:
  US08/831,052
• Time in Patent Office: 1,190 Days
• Field of Search: 607/4, 607/5
• US Class Current: 607/4
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/395 for treating atrial fibrillation
• CPC Class Codes: A61N 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion

Abstract

A method and apparatus for detecting and treating atrial fibrillation. In response to detecting atrial fibrillation, the device derives an escape interval based on one or more preceding intervals between ventricular depolarizations. The escape interval is initiated in response to a ventricular depolarization, and in response to the expiration of the escape interval, an atrial cardioversion pulse is delivered. In one embodiment of the invention, the cardioverting pulse is delivered immediately upon expiration of the derived escape interval. In a second embodiment of the invention, a ventricular pacing pulse is delivered on expiration of the escape interval, with an atrial cardioversion pulse following after a short delay.

Claims

1. An atrial cardioverter or defibrillator, comprising:

means for detecting a tachyarrhythmia in a patient'"'"'s atrium;

means for delivering a cardioversion or defibrillation pulse to said patient'"'"'s atrium; and

synchronization means for triggering delivery of said cardioversion or defibrillation pulse, said synchronization means comprising;

means for sensing depolarizations of said patient'"'"'s ventricle;

means for measuring intervals between sensed ventricular depolarizations to derive an interval indicative of intrinsic heart rate;

means for deriving an escape interval less than said interval indicative of intrinsic heart rate, initiated on a sensed ventricular depolarization; and

means for triggering delivery of said cardioversion or defibrillation pulse in response to expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval.

3. An atrial cardioverter or defibrillator according to claim 1 or claim 2, wherein said triggering means comprises means for triggering delivery of said cardioversion or defibrillation pulse on expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval.

9. A method according to claim 3 or claim 8, wherein said delivering step comprises delivering said cardioversion or defibrillation pulse on expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval.

2. An atrial cardioverter or defibrillator, comprising:

means for detecting a tachyarrhythmia in a patient'"'"'s atrium;

means for delivering a cardioversion or defibrillation pulse to said patient'"'"'s atrium; and

synchronization means for triggering delivery of said cardioversion or defibrillation pulse, said synchronization means comprising;

means for sensing depolarizations of said patient'"'"'s ventricle;

means for measuring intervals between sensed ventricular depolarizations to determine an interval indicative of intrinsic heart rate;

means for defining a single escape interval less than said interval indicative of intrinsic heart rate, initiated on a said sensed ventricular depolarization; and

means for triggering delivery of said cardioversion or defibrillation pulse in response to expiration of said single escape interval, in the absence of sensed ventricular depolarizations during said single escape interval.

4. An atrial cardioverter or defibrillator comprising:

means for detecting a tachyarrhythmia in a patient'"'"'s atrium;

means for delivering a cardioversion or defibrillation pulse to said patient'"'"'s atrium; and

synchronization means for triggering delivery of said cardioversion or defibrillation pulse, said synchronization means comprising;

means for sensing depolarizations of said patient'"'"'s ventricle;

means for measuring intervals between sensed ventricular depolarizations;

means for deriving an escape interval initiated on a sensed ventricular depolarization, based upon measured intervals between sensed ventricular depolarizations;

means for triggering delivery of said cardioversion or defibrillation pulse in response to expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval; and

means for delivering a pacing pulse to said patient'"'"'s ventricle on expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval, and wherein said triggering means comprises means for triggering delivery of said cardioversion or defibrillation pulse on expiration of a delay interval following expiration of said escape interval.

5. An atrial cardioverter or defibrillator according to claim 4, further comprising capture detection means for determining whether said delivered pacing pulse caused a depolarization of said patient'"'"'s ventricle and wherein said triggering means comprises means responsive to said capture detection means for preventing delivery of said cardioversion or defibrillation pulse if said pacing pulse does not cause a ventricular depolarization.

6. An atrial cardioverter or defibrillator, comprising:

means for detecting a tachyarrhythmia in a patient'"'"'s atrium;

means for delivering a cardioversion or defibrillation pulse to said patient'"'"'s atrium; and

synchronization means for triggering delivery of said cardioversion or defibrillation pulse, said synchronization means comprising;

means for sensing depolarizations of said patient'"'"'s ventricle;

means for measuring intervals between sensed ventricular depolarizations;

means for deriving an escape interval initiated on a sensed ventricular depolarization, based upon measured intervals between sensed ventricular depolarizations; and

means for triggering delivery of said cardioversion or defibrillation pulse in response to expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval; and

wherein said deriving means comprises means for determining whether said derived escape interval is less than a minimum interval, and means for preventing delivery of said cardioversion or defibrillation pulse if said derived interval is less than said minimum interval.

7. A method of atrial cardioversion or defibrillation, comprising:

detecting a tachyarrhythmia in a patient'"'"'s atrium;

sensing depolarizations of said patient'"'"'s ventricle;

measuring intervals between sensed ventricular depolarizations to derive an interval indicative of intrinsic heart rate;

deriving an escape interval less than said interval indicative of intrinsic heart rate, initiated on a sensed ventricular depolarization; and

delivering a cardioversion or defibrillation pulse to said patient'"'"'s atrium in response to expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval.

8. A method of atrial cardioversion or defibrillation, comprising:

detecting a tachyarrhythmia in a patient'"'"'s atrium;

sensing depolarizations of said patient'"'"'s ventricle;

measuring intervals between sensed ventricular depolarizations to derive an interval indicative of intrinsic heart rate;

deriving an escape interval less than said interval indicative of intrinsic heart rate, initiated on a sensed ventricular depolarization; and

delivering a cardioversion or defibrillation pulse to said patient'"'"'s atrium in response to expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval.

10. A method of atrial cardioversion or defibrillation, comprising:

detecting a tachyarrhythmia in a patient'"'"'s atrium;

sensing depolarizations of said patient'"'"'s ventricle,

measuring intervals between sensed ventricular depolarizations;

deriving an escape interval initiated on a sensed ventricular depolarization, based upon measured intervals between sensed ventricular depolarizations; and

delivering a cardioversion or defibrillation pulse to said patient'"'"'s atrium in response to expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval; and

delivering a pacing pulse to said patient'"'"'s ventricle on expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval, and wherein said step of delivering said cardioversion or defibrillation pulse comprises delivering said cardioversion or defibrillation pulse on expiration of a delay interval following expiration of said escape interval.

11. A method according to claim 10, further comprising the step of determining whether said delivered pacing pulse caused a depolarization of said patient'"'"'s ventricle and the step of preventing delivery of said cardioversion or defibrillation pulse if said pacing pulse does not cause a ventricular depolarization.

12. A method of atrial cardioversion or defibrillation, comprising:

detecting a tachyarrhythmia in a patient'"'"'s atrium;

sensing depolarizations of said patient'"'"'s ventricle;

measuring intervals between sensed ventricular depolarizations;

deriving an escape interval initiated on a sensed ventricular depolarization, based upon measured intervals between sensed ventricular depolarizations; and

delivering a cardioversion or defibrillation pulse to said patient'"'"'s atrium in response to expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval; and

wherein said deriving step comprises determining whether said derived escape interval is less than a minimum interval, and further comprising the step of preventing delivery of said cardioversion or defibrillation pulse if said derived interval is less than said minimum interval. .Iadd.

14. interval. .Iaddend..Iadd.21. A method according to claim 20, further comprising the step of determining whether said delivered pacing pulse caused a depolarization of said patient'"'"'s ventricle and the step of preventing delivery of said cardioversion or defibrillation pulse if said pacing pulse does not cause a ventricular depolarization. .Iaddend..Iadd.22. A method of atrial cardioversion or defibrillation, comprising:

detecting a tachyarrhythmia in a patient'"'"'s atrium;

sensing depolarizations of said patient'"'"'s ventricle;

measuring one or more intervals between sensed ventricular depolarizations;

deriving an escape interval initiated on a sensed ventricular depolarization, based upon said one or more measured intervals between sensed ventricular depolarizations; and

delivering a cardioversion or defibrillation pulse to said patient'"'"'s atrium in response to expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval; and

wherein said deriving step comprises determining whether said derived escape interval is less than a minimum interval, and further comprising the step of preventing delivery of said cardioversion or defibrillation pulse if said derived interval is less than said minimum interval. .Iaddend..Iadd.23. An atrial cardioverter or defibrillator, comprising;

means for detecting a tachyarrhythmia in a patient'"'"'s atrium;

means for delivering a cardioversion or defibrillation pulse to said patient'"'"'s atrium; and

synchronization means for triggering delivery of said cardioversion or defibrillation pulse, said synchronization means comprising;

means for sensing depolarizations of said patient'"'"'s ventricle;

means for measuring one or more intervals between sensed ventricular depolarizations to derive an interval indicative of intrinsic heart rate;

means for deriving an escape interval initiated on a sensed ventricular depolarization and based on said one or more measured intervals including a measured interval ending with the sensed depolarization on which said escape interval is initiated; and

means for triggering delivery of said cardioversion or defibrillation pulse in response to expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval.

15. Iaddend..Iadd.24. An atrial cardioverter or defibrillator according to claim 23, wherein said triggering means comprises means for triggering delivery of said cardioversion or defibrillation pulse on expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval. .Iaddend..Iadd.25. A method of atrial cardioversion or defibrillation, comprising:

detecting a tachyarrhythmia in a patient'"'"'s atrium;

sensing depolarizations of said patient'"'"'s ventricle;

measuring one or more intervals between sensed ventricular depolarizations to derive an interval indicative of intrinsic heart rate;

deriving an escape interval initiated on a sensed ventricular depolarization and based on said one or more measured intervals including a measured interval ending with the sensed depolarization on which said escape interval is initiated; and

delivering a cardioversion or defibrillation pulse to said patient'"'"'s atrium in response to expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval. .Iaddend..Iadd.26. A method according to claim 25, wherein said delivering step comprises delivering said cardioversion or defibrillation pulse on expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval. .Iaddend.

13. An atrial cardioverter or defibrillator, comprising:

means for detecting a tachyarrhythmia in a patient'"'"'s atrium;

means for delivering a cardioversion or defibrillation pulse to said patient'"'"'s atrium; and

synchronization means for triggering delivery of said cardioversion or defibrillation pulse, said synchronization means comprising;

means for sensing depolarizations of said patient'"'"'s ventricle;

means for measuring one or more intervals between sensed ventricular depolarizations to derive an interval indicative of intrinsic heart rate;

means for deriving an escape interval less than said interval indicative of intrinsic heart rate, initiated on a sensed ventricular depolarization; and

means for triggering delivery of said cardioversion or defibrillation pulse in response to expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval. .Iaddend..Iadd.14. An atrial cardioverter or defibrillator according to claim 13 wherein said triggering means comprises means for triggering delivery of said cardioversion or defibrillation pulse on expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval. .Iaddend..Iadd.15. An atrial cardioverter or defibrillator comprising;

means for detecting a tachyarrhythmia in a patient'"'"'s atrium;

means for delivering a cardioversion or defibrillation pulse to said patient'"'"'s atrium; and

synchronization means for triggering delivery of said cardioversion or defibrillation pulse, said synchronization means comprising;

means for sensing depolarizations of said patient'"'"'s ventricle;

means for measuring one or more intervals between sensed ventricular depolarizations;

means for deriving an escape interval initiated on a sensed ventricular depolarization, based upon said one or more measured intervals between sensed ventricular depolarizations;

means for triggering delivery of said cardioversion or defibrillation pulse in response to expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval; and

means for delivering a pacing pulse to said patient'"'"'s ventricle on expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval; and

wherein said triggering means comprises means for triggering delivery of said cardioversion or defibrillation pulse on expiration of a delay interval following expiration of said escape interval. .Iaddend..Iadd.16. An atrial cardioverter or defibrillator according to claim 15, further comprising capture detection means for determining whether said delivered pacing pulse caused a depolarization of said patient'"'"'s ventricle and wherein said triggering means comprises means responsive to said capture detection means for preventing delivery of said cardioversion or defibrillation pulse if said pacing pulse does not cause a ventricular depolarization. .Iaddend..Iadd.17. An atrial cardioverter or defibrillator, comprising;

means for detecting a tachyarrhythmia in a patient'"'"'s atrium;

means for delivering a cardioversion or defibrillation pulse to said patient'"'"'s atrium; and

synchronization means for triggering delivery of said cardioversion or defibrillation pulse, said synchronization means comprising;

means for sensing depolarizations of said patient'"'"'s ventricle;

means for measuring one or more intervals between sensed ventricular depolarizations;

means for deriving an escape interval initiated on a sensed ventricular depolarization, based upon said one or more measured intervals between sensed ventricular depolarizations; and

means for triggering delivery of said cardioversion or defibrillation pulse in response to expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval; and

wherein said deriving means comprises means for determining whether said derived escape interval is less than a minimum interval, and means for preventing delivery of said cardioversion or defibrillation pulse if said derived interval is less than said minimum interval. .Iaddend..Iadd.18. A method of atrial cardioversion or defibrillation, comprising;

detecting a tachyarrhythmia in a patient'"'"'s atrium;

sensing depolarizations of said patient'"'"'s ventricle;

measuring one or more intervals between sensed ventricular depolarizations to derive an interval indicative of intrinsic heart rate;

deriving an escape interval less than said interval indicative of intrinsic heart rate, initiated on a sensed ventricular depolarization; and

delivering a cardioversion or defibrillation pulse to said patient'"'"'s atrium in response to expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval. .Iaddend..Iadd.19. A method according to claim 18, wherein said delivering step comprises delivering said cardioversion or defibrillation pulse on expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval. .Iaddend..Iadd.20. A method of atrial cardioversion or defibrillation, comprising;

detecting a tachyarrhythmia in a patient'"'"'s atrium;

sensing depolarizations of said patient'"'"'s ventricle;

measuring one or more intervals between sensed ventricular depolarizations;

deriving an escape interval initiated on a sensed ventricular depolarization, based upon said one or more measured intervals between sensed ventricular depolarizations; and

delivering a cardioversion or defibrillation pulse to said patient'"'"'s atrium in response to expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval; and

delivering a pacing pulse to said patient'"'"'s ventricle on expiration of said escape interval, in the absence of sensed ventricular depolarizations during said escape interval; and

wherein said step of delivering said cardioversion or defibrillation pulse comprises delivering said cardioversion or defibrillation pulse on expiration of a delay interval following expiration of said escape