Tachyarrhythmia pacer

• US 4,493,325 A
• Filed: 05/03/1982
• Issued: 01/15/1985
• Est. Priority Date: 05/03/1982
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Hartlaub, Jerome T., Beckmann, Paul J.
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): Shein, Mitchell J.
• Application Number:
  US06/374,457
• Time in Patent Office: 988 Days
• Field of Search: 128/419 PG, 128/419 D, 128/705-706
• US Class Current: 607/14
• CPC Class Codes: A61N 1/3621 for treating or preventing abnormally high heart rate

Abstract

A pacer subsystem for detecting the existence of tachyarrhythmia including means for measuring the average time interval between successive heart beats and for comparing a sample beat with both a percentage of this average, and with a preset time interval. If the sample beat period is less than both criteria, it is classified as a tachy beat. If the sample beat is longer than either time interval it is classified as a non-tachy beat. Sequences of tachy beats are used to initiate an appropriate therapeutic stimulation regime.

Claims

1. In a pacer of the type having at least one sense amplifier for detecting depolarization of cardiac tissue and, at least one output amplifier for providing electrical stimulation to the cardiac tissue;

an improved tachyarrhythmia detection system comprising;

timing means for determining time periods between successive cardiac depolarizations;

averaging means for calculating the average time period for a preselected number of said time periods producing a running average period;

means for calculating a running average threshold period from said running average period;

means for comparing a time period with said running average threshold period producing a first criteria detection signal if said time period is less than or equal to said running average threshold period;

means for comparing said time period to a preselected programmed threshold period and for producing a second criteria detection signal if said time period is less than or equal to programmed threshold period; and

means responsive to said first and second criteria detection signals for incrementing a tachy beat counter; and

means responsive to said tachy beat counter for initiating a tachyarrythmia treatment regime.

2. The device of claim 1 further including a telemetry system means for permitting the non-invasive interrogation of said tachy beat counter.

3. The device of claim 2 wherein said telemetry system means further including means for the non-invasive alteration of said tachy beat counter.

4. The device of claim 2 wherein said telemetry system means permits the non-invasive alteration of said running average threshold period.

5. The device of claim 2 wherein said telemetry system means permits the non-invasive alteration of said programmed threshold period.

6. The device of claim 2 wherein said telemetry system means permits the non-invasive alteration of said preselected number of said time periods.