Implantable cardiac pacer with programmable antitachycardia mechanisms

• US 4,875,483 A
• Filed: 12/17/1987
• Issued: 10/24/1989
• Est. Priority Date: 10/17/1983
• Status: Expired due to Term

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories), Credit Lyonnais (New York) (Crédit Lyonnais SA), Midland Bank Plc (Hong Kong Branch) (HSBC Holdings plc)
• Original Assignee: Telectronics Incorporated
• Inventors: Vollmann, William, Mumford, Van E.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US07/134,464
• Time in Patent Office: 677 Days
• Field of Search: 128/419 PG
• US Class Current: 607/15
• CPC Class Codes: A61N 1/3621 for treating or preventing abnormally high heart rate
• CPC Class Codes: A61N 1/37211 Means for communicating with stimulators
• CPC Class Codes: A61N 1/37264 Changing the program; Upgrading firmware

Abstract

A multi-programmable ROM-less cardiac pacer employs an intermittent microprocessor turned ON and OFF by a pacer timer clockwise independent of the processor to time intervals preset by the processor. Sensed activity and external communications restart the processor with an interrupt request. Five antitachycardia mechanisms are externally programmable: programmed burst, burst rate scanning, automatic overdrive, programmed critically timed and critically timed scanning. In scanning mechanisms, the interval changes progressively until the tachycardia is terminated by a successful interval which is stored. Runaway protection is executed in the software. For telemetry, the pacer collects the following monitored pacing data over a programmable period of time: percent pacing, average rate, maximum rate, number of tachycardia episodes and maximum tachycardia duration.

Claims

1. An implantable cardiac stimulator, comprising:

an electrical terminal for connection to cardiac tissue;

sensing means connected to said terminal for producing a sense output indicative of cardiac activity;

output means connected to said terminal for applying a stimulation pulse via said terminal on command;

storage means containing selectable, programmable antitachycardia parameters representative of a sequence of stimulation commands and corresponding to either programmed burst, burst rate scanning, automatic overdrive, programmed critically timed, or critically timed scanning;

means for executing the selected sequence of stimulation commands stored in said storage means;

means for setting a programmable tachycardia threshold rate;

tachycardia detection means for issuing an arrhthymia output signal when the tachycardia threshold rate is exceeded a given number of times; and

antitachycardia means responsive to the arrhthymia output signal for causing said storage means under control of the executing means to apply the programmable sequence of stimulation commands to said output means.

2. A cardiac pacer with tachycardia response comprising:

an electrical terminal for connection with cardiac tissue;

sensing means connected to said terminal for producing a sense output indicative of cardiac activity;

output means for applying stimulation pulses via said terminal on command;

storage means containing selectable, programmable antitachycardia parameters representative of a sequence of stimulation commands and corresponding to automatic overdrive;

means for executing the selected sequence of stimulation commands stored in said storage means;

means for setting a predetermined tachycardia threshold rate;

means for determining the average rate of a predetermined number of preceding sensed outputs;

tachycardia detection means responsive to said sensed output exceeding the predetermined threshold rate for issuing an arrhythmia signal; and

antitachycardia means enabled by said arrhythmia signal for causing the storage means under control of the executing means to apply a burst of a predetermined number of output pulse commands at a rate faster than the average rate of a predetermined number of preceding sensed outputs.