Implantable atrial defibrillator having ischemia coordinated intervention therapy and method

• US 5,531,768 A
• Filed: 02/21/1995
• Issued: 07/02/1996
• Est. Priority Date: 02/21/1995
• Status: Expired due to Term

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: InControl, Inc. (Daikin Industries Ltd)
• Inventors: Alferness, Clifton A.
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): Getzow, Scott M.
• Application Number:
  US08/391,156
• Time in Patent Office: 497 Days
• Field of Search: 607/4, 607/5, 607/6, 607/14, 128/696, 128/702, 128/705
• US Class Current: 607/6
• 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

An atrial defibrillator coordinates atrial cardioversion with ischemia detection. The defibrillator includes a plurality of sense amplifiers for sensing electrical activity of a heart. An ischemia detector is responsive to the sensed electrical activity of the heart for detecting ischemia of the heart. An atrial fibrillation detector is responsive to the sensed electrical activity of the heart for determining if the atria are in need of cardioversion, and a cardiovertor applies cardioverting electrical energy to the atria of the heart if the atria of the heart are in need of cardioversion and if the ischemia detector fails to detect ischemia of the heart.

Claims

1. An atrial defibrillator comprising:

sensing means for sensing electrical activity of a heart;

an ischemia detector responsive to the sensed electrical activity of the heart for detecting ischemia of the heart;

an atrial fibrillation detector responsive to the sensed electrical activity of the heart for determining if the atria are in need of cardioversion; and

cardioverting means for applying cardioverting electrical energy to the atria of the heart if the atria of the heart are in need of cardioversion and if the ischemia detector fails to detect ischemia of the heart.

2. An atrial defibrillator as defined in claim 1 further including ischemia data generating means for generating ischemia data responsive to the sensed electrical activity of the heart and memory means for storing the ischemia data when the ischemia detector detects ischemia of the heart.

3. An atrial defibrillator as defined in claim 2 wherein the ischemia data includes ST segment deviation data.

4. An atrial defibrillator as defined in claim 2 wherein the ischemia data includes data representative of T wave morphology of the heart.

5. An atrial defibrillator as defined in claim 2 further including telemetry means for transmitting the stored ischemia data to a nonimplanted external receiver.

6. An atrial defibrillator as defined in claim 1 wherein the atrial fibrillation detector determines if the atria are in need of cardioversion if the ischemia detector first fails to detect ischemia of the heart.

7. An atrial defibrillator as defined in claim 1 further including heart activity data generating means for generating heart activity data responsive to the sensed electrical activity of the heart and memory means for storing said heart activity data, said atrial fibrillation detector and said ischemia detector being responsive to the stored heart activity data.

8. An atrial defibrillator as defined in claim 7 wherein the heart activity data includes data representing ST segment amplitudes of the heart.

9. An atrial defibrillator as defined in claim 7 wherein the heart activity data includes data representative of T wave morphology of the heart.

10. An atrial defibrillator as defined in claim 9 wherein the T wave morphology data is representative of T wave width.

11. An atrial defibrillator as defined in claim 1 wherein the sensing means includes first sensing means for sensing electrical activity of the right ventricle of the heart to produce a first electrogram signal.

12. An atrial defibrillator as defined in claim 1 wherein the sensing means includes second sensing means for sensing electrical activity of the heart between the coronary sinus or great vein of the heart and the right ventricle of the heart to produce a second electrogram signal.

13. An atrial defibrillator as defined in claim 12 wherein the sensing means includes a third sensing means for sensing electrical activity of the heart between the right atrium and the coronary sinus or great vein of the heart to produce a third electrogram signal.

14. An atrial defibrillator as defined in claim 13 further including subtracting means for subtracting the third electrogram signal from the second electrogram signal to produce a fourth electrogram signal.

15. An atrial defibrillator as defined in claim 14 wherein the ischemia detector is responsive to the second and fourth electrogram signals for detecting ischemia of the heart.

16. A method of providing therapy to the atria of a heart, said method comprising the steps of:

sensing activity of the heart;

analyzing the sensed activity to detect for ischemia of the heart;

determining from the sensed activity if the atria are in need of cardioversion;

providing cardioverting therapy to the atria if the atria are in need of cardioversion and if ischemia of the heart is not detected; and

withholding therapy to the atria if ischemia of the heart is detected.

17. A method as defined in claim 16 further including the step of generating ischemia data responsive to the sensed electrical activity of the heart and storing the ischemia data in memory when ischemia of the heart is detected.

18. A method as defined in claim 17 wherein the ischemia data includes ST segment deviation data.

19. A method as defined in claim 17 wherein the ischemia data includes data representative of T wave morphology of the heart.

20. A method as defined in claim 17 including the further step of transmitting the stored ischemia data to a nonimplanted external receiver.

21. A method as defined in claim 16 wherein the step of determining if the atria are in need of cardioversion is performed only if ischemia of the heart is not detected.

22. A method as defined in claim 16 further including the steps of generating heart activity data responsive to the sensed electrical activity of the heart, and storing the heart activity data, wherein said analyzing and determining steps being performed with the stored heart activity data.

23. A method as defined in claim 22 wherein the heart activity data includes data representing ST segment amplitudes of the heart.

24. A method as defined in claim 22 wherein the heart activity data includes data representative of T wave morphology of the heart.

25. A method as defined in claim 24 wherein the T wave morphology data is representative of T wave width.

26. A method as defined in claim 16 wherein the sensing step includes sensing electrical activity of the right ventricle of the heart.

27. A method as defined in claim 16 wherein the sensing step includes sensing electrical activity of the heart between the coronary sinus or great vein of the heart and the right ventricle of the heart.

28. A method as defined in claim 16 wherein the sensing step includes establishing electrical contact between the right atrium of the heart and a right atrial electrode, establishing electrical contact between the right ventricle of the heart and a right ventricular electrode, and generating an electrogram signal representing the electrical activity of the heart between the right atrial and the right ventricular electrodes.

29. A method as defined in claim 28 wherein the sensing step includes sensing electrical activity of the heart between the right atrium and the coronary sinus or grat vein of the heart to produce a right atrium to coronary sinus electrogram signal.

30. A method as defined in claim 29 wherein the sensing step includes sensing electrical activity of the heart between the coronary sinus or great vein of the heart and the right ventricle of the heart to produce a right ventricle to coronary sinus electrogram signal.

31. A method as defined in claim 30 wherein the sensing step includes subtracting the right atrium to coronary sinus electrogram signal from the right ventricle to coronary sinus electrogram signal to produce the electrogram signal representing the electrical activity of the heart between the right atrial and right ventricular electrode.

32. An atrial defibrillator comprising:

sensing means for sensing electrical activity of a heart;

an ischemia detector responsive to the sensed electrical activity of the heart for detecting ischemia of the heart;

an atrial fibrillation detector responsive to the sensed electrical activity of the heart for determining if the atria are in need of cardioversion; and

therapy means for providing a predetermined therapy to the atria of the heart if the atria of the heart are in need of cardioversion and if the ischemia detector fails to detect ischemia of the heart and for altering said predetermined therapy if the atria are in need of cardioversion and the ischemia detector detects ischemia of the heart.

33. A method of providing therapy to the atria of a heart, said method comprising the steps of:

sensing activity of the heart;

analyzing the sensed activity to detect for ischemia of the heart;

determining from the sensed activity if the atria are in need of cardioversion;

providing a predetermined therapy to the atria if the atria are in need of cardioversion and if ischemia of the heart is not detected; and

altering said predetermined therapy if ischemia of the heart is detected.