Therapy termination in an atrial defibrillator and method

• US 5,554,175 A
• Filed: 11/29/1994
• Issued: 09/10/1996
• Est. Priority Date: 11/29/1994
• 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): LAYNO, CARL HERNANDZ
• Application Number:
  US08/346,500
• Time in Patent Office: 651 Days
• Field of Search: 607/4, 607/5
• US Class Current: 607/5
• 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 applies cardioverting electrical energy to the atria of a heart when in need of cardioversion. The atrial defibrillator includes an atrial fibrillation detector for determining if the atria of a heart are in need of cardioversion, and a therapy sequencer for performing a therapy sequence to apply cardioverting electrical energy to the atria when the atria are in need of cardioversion. The therapy sequence is terminated when the atrial fibrillation detector fails at least twice in succession to determine that the atria are in need of cardioversion. As a result, a greater atrial fibrillation detection sensitivity is employed for terminating a therapy sequence as is employed for initiating the therapy sequence.

Claims

1. An atrial defibrillator comprising:

therapy means for performing a therapy sequence including cardioverting the atria of a human heart when the atria are in need of cardioversion;

an atrial fibrillation detector for determining if the atria of the heart are in need of cardioversion, the atrial fibrillation detector having a first sensitivity and a second sensitivity for detecting when the atria are in need of cardioversion, said second sensitivity being greater than said first sensitivity;

means for causing said atrial fibrillation detector to determine with said first sensitivity if the atria are in need of cardioversion;

means for initiating said therapy sequence if the atrial fibrillation detector detects with the first sensitivity that the atria are in need of cardioversion;

second means for causing said atrial fibrillation detector during said therapy sequence to determine with said second sensitivity if the atria are still in need of cardioversion; and

means for terminating said therapy sequence if the atrial fibrillation detector fails to detect with the second sensitivity that the atria are still in need of cardioversion.

2. An atrial defibrillator comprising:

an atrial fibrillation detector for determining if the atria of a heart are in need of cardioversion;

therapy means for performing a therapy sequence to apply cardioverting electrical energy to the atria when the atria are in need of cardioversion; and

,

means for terminating the therapy sequence when the atrial fibrillation detector fails at least twice in succession to determine that the atria are in need of cardioversion.

3. An atrial defibrillator for applying cardioverting electrical energy to the atria of a heart when in need of cardioversion, said atrial defibrillator comprising:

sensing means for sensing atrial activity of the heart;

an atrial fibrillation detector responsive to the sensing means for determining when cardioversion is needed;

initiating means for initiating a cardioversion therapy sequence; and

,

therapy sequence control means for controlling said cardioversion therapy sequence and providing therapy sequence control commands including a cardioversion command;

a first command to the atrial fibrillation detector, during said sequence, to cause the atrial fibrillation detector to determine if cardioversion is needed, and a second command to the atrial fibrillation detector to cause the atrial fibrillation detector to determine if cardioversion is needed responsive to the atrial fibrillation detector failing to determine a need for cardioversion in response to the first command; and

a cardiovertor for applying the cardioverting electrical energy to the atria in response to said therapy sequence control means providing the cardioversion command,

wherein said therapy sequence control means provides the first command prior to providing the cardioversion command and further includes means for terminating said sequence in response to the atrial fibrillation detector failing to determine a need for cardioversion in response to both the first and second commands.

4. An atrial defibrillator as defined in claim 3 wherein said therapy sequence control means provides the second command to the atrial fibrillation detector immediately after the atrial fibrillation detector fails to determine a need for cardioversion in response to the first command.

5. An atrial defibrillator as defined in claim 3 wherein said therapy sequence control meansincludes means for repeatedly providing a cardioversion command to said cardiovertor and means for providing the first command after each application of cardioverting electrical energy to the atria by the cardiovertor.

6. A method of providing cardioverting therapy to the atria of a heart, the method including the steps of:

sensing atrial activity of the heart;

detecting from the sensed atrial activity with a first sensitivity if the atria are in need of cardioversion; and

,

initiating a therapy sequence upon detecting that the atria are in need of cardioversion, the therapy sequence including applying cardioverting electrical energy to the atria of the heart, redetecting with a second sensitivity if the atria are in need of cardioversion, and terminating said therapy sequence after the redetecting step if the atria are not in need of cardioversion,

said second sensitivity being greater than said first sensitivity.

7. A method of providing cardioverting therapy to the atria of a heart, the method including the steps of:

sensing atrial activity of the heart;

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

initiating a therapy sequence upon detecting that the atria are in need of cardioversion, the therapy sequence including applying cardioverting electrical energy to the atria of the heart, determining if the atria are in need of cardioversion, and redetermining if the atria are in need of cardioversion if the determining step fails to determine a need for cardioversion; and

,

terminating the therapy sequence if the redetermining step fails to determine a need for cardioversion.

8. A method as defined in claim 7 wherein said determining and redetermining steps are performed prior to said applying step.

9. A method as defined in claim 7 wherein said determining and redetermining steps are performed after said applying step.

10. A method as defined in claim 7 wherein said determining and redetermining steps are performed before said applying step and are repeated after said applying step.

11. A method as defined in claim 7 wherein said redetermining step is performed immediately after said determining step.

12. In an atrial defibrillator which initiates therapy intervention upon initial detection of fibrillation of the atria and which terminates the therapy intervention upon detection of an absence of atrial fibrillation after initiation of therapy intervention, an atrial fibrillation detector comprising:

a processor for analyzing cardiac data under control of a first atrial fibrillation detection algorithm to initially detect atrial fibrillation and initiate therapy intervention; and

means for causing the processor to analyze cardiac data under control of a second atrial fibrillation detection algorithm to detect the absence of atrial fibrillation after the initial detection of atrial fibrillation;

wherein the second atrial fibrillation detection algorithm is different than the first atrial fibrillation detection algorithm.