Tachycardia detection for automatic implantable cardioverter/defibrillator with atrial and ventricular sensing capability

• US 4,860,749 A
• Filed: 01/06/1988
• Issued: 08/29/1989
• Est. Priority Date: 01/06/1988
• Status: Expired due to Fees

• Current Assignee: Wayne State University
• Original Assignee: Wayne State University
• Inventors: Lehmann, Michael H.
• Primary Examiner(s): Jaworski, Francis
• Assistant Examiner(s): MANUEL, GEORGE C
• Application Number:
  US07/141,280
• Time in Patent Office: 601 Days
• Field of Search: 128/419 D, 128/419 PG, 128/419 P
• 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 1/39622 Pacing therapy

Abstract

An automatic tachycardia detection assembly to be implanted in a person for stimulating the heart upon detection of abnormal tachycardias. The assembly includes an atrial sensor (16) and ventricular sensor (18) for sensing activity within the atria and ventricles of the heart, respectively. Also included is an electrical stimulator or cardioverter/defibrillator (20, 22) for therapeutically stimulating the heart upon detection of abnormal tachycardias. The assembly (10) includes a housing (12) enclosing a control circuit (14) to be implanted within a person responsive to the sensors (16, 18) controlling the cardioverter/defibrillator (20, 22). The control circuit (14) distinguishes sinus tachycardia from ventricular tachycardia having 1:1 VA conduction by comparing the measured tachycardia AV interval to a predetermined sinus AV interval.

Claims

1. An automatic tachycardia detection and cardiac stimulating assembly adapted to be implanted in a person for stimulating the heart of the person upon detection of an abnormal tachycardia, said assembly comprising;

atrial sensing means (16) for sensing electrophysiological activity within an atrium of said heart ventricular sensing means (18) for sensing electrophysiological activity within a ventricle stimulation means (20,

     22) adapted to be connected to the heart for electrically and therapeutically stimulating the heart, and control (14) operatively connected to said atrial sensing means and said ventricular sensing means and said stimulating means and responsive to said sensed activity from said atrial sensing means (16) and said ventricular sensing means (18) for (a) determining cycle length of atrial activity and cycle length of ventricular activity (b) for determining the atrium to ventricle time interval (AV interval) (c) detecting ventricular tachycardia from said determined ventricular cycle length and actuating said stimulating means (20,

     22) when ventricular tachycardia is detected, and (d) for distinguishing sinus tachycardia when the determined ventricular cycle length is equal to the determined atrial cycle length and the AV interval during tachycardia is less than or equal to a predetermined AV interval representing a normal sinus AV conduction interval and preventing activation of said stimulating means, thereby to prevent unnecessary stimulation of the heart.

2. A method of detecting tachycardia in a heart and stimulating the heart in response to the detecting the method including the steps of;

sensing electrophysiological activity within an atrium, sensing electrophysiological activity within a ventricle, determining atrial cycle length of the activity within the atrium and ventricular cycle length of the activity within the ventricle, determining ventricular tachycardia from said cycle lengths and stimulating the heart in response thereto while preventing unnecessary stimulation of the heart when the sensed ventricular cycle length is equal to the sensed atrial cycle length and sinus tachycardia detected by the atrium to ventricle time interval (AV interval) length of a beat during tachycardia is less than or equal to a predetermined AV interval representing normal sinus rhythm.

3. A method as set forth in claim 2 further including detecting when the sensed ventrical cycle length is less than a threshold value representing the value below which tachycardia can occur and preventing stimulating when above the threshold value.

4. A method as set forth in claim 3 further including stimulating the heart when the ventricular cycle length is less than or equal to a predetermined value representing the value below which hemodynamically significant tachycardia is presumed.

5. A method as set forth in claim 4 further including stimulating the heart when the ventricular cycle length is less than the atrial cycle length and the ventrical cycle length is less than or equal to the predetermined value.

6. A method as set forth in claim 5 further including stimulating the heart when the ventricular cycle length equals the atrial cycle length and the AV interval is not constant.

7. A method as set forth in claim 6 further including stimulating the heart when the ventricular cycle length equals the atrial cycle length and the ventricular cycle length is less than or equal to a crossover value representing a value below which abnormal tachycardia may occur having a 1:

1 VA conduction.

8. A method as set forth in claim 7 further including stimulating the heart when the ventricular cycle length equals the atrial cycle length and exceeds said crossover value and the tachycardia AV interval is greater than or equal to the sinus AV interval, and preventing firing when tachycardia AV interval is less than the sinus AV interval.

9. A method as set forth in claim 8 further including stimulating the heart when the ventricular cycle length is not less than or equal to the atrial cycle length and the AV interval is not constant and the ventricular cycle length is constant, and preventing stimulation of the heart when the AV interval is constant or when the ventricular cycle length is not constant.

10. An automatic tachycardia detection and cardiac stimulating assembly adapted to be implanted in a person for stimulating the heart of the person upon detection of an abnormal tachycardia, said assembly comprising;

atrial sensing means (16) for sensing electrophysiological activity within the atrium of said heart ventricular sensing means (18) for sensing electrophysiological activity within the ventricle, stimulation means (20,

     22) for stimulating the heart to control the heart rate, and control means (14) operatively connected to said atrial sensing means and said ventricular sensing means and said stimulation means and responsive to said sensed activity from said atrial sensing means (16) and said ventricular sensing means (18) for determining ventricular cycle length and atrium to ventricular time interval (AV interval), for detecting ventricular tachycardia from said ventricular cycle length and said AV time interval and actuating said stimulation means (20,

     22) when tachycardia is detected.

11. A control mechanism for an automatic tachycardia detector assembly to be implanted in a person for stimulating the heart upon detection of abnormal tachycardias including an atrial sensor (16) and ventricular sensor (18) for sensing electrophysiological activity and cycle length of successive beats in the heart and a stimulator (20, 22) for electrically and therapeutically stimulating the heart, said control mechanism (14) including input means for being responsive to the atrial sensor (16) and the ventricular sensor (18) for determining the atrium to ventricular time interval (AV interval) detecting ventricular tachycardia output means for and actuating the stimulator (20, 22) and for distinguishing sinus tachycardia when the ventricular cycle length is equal to the atrial cycle length and the AV interval during tachycardia is less than or equal to a predetermined AV interval normal sinus AV interval to prevent unnecessary stimulation of the heart.

12. A method of detecting ventricular tachycardia and stimulating a heart the method including the steps of;

sensing electrophysiological activity within an atrium measuring the atrial cycle length sensing electrophysiological activity within a ventricle, measuring the ventricular cycle length measuring the atrial to ventricular conduction time interval (AV interval) representative of the time between sensed electrophysiological activity within the atrium and sensed electrophysiological activity ventrical, and comparing the measured AV interval and the ventricle cycle length and the atrial cycle length for determining whether tachycardia is present and stimulating the heart when tachycardia is present.