Implantable cardiac stimulator wherein the pacing rate is controlled dependent on variations in the spontaneous interval

• US 6,246,909 B1
• Filed: 12/09/1999
• Issued: 06/12/2001
• Est. Priority Date: 10/04/1996
• Status: Expired due to Term

• Current Assignee: Pacesetter AB
• Original Assignee: Pacesetter AB
• Inventors: Ekwall, Christer
• Primary Examiner(s): Jastrzab, Jeffrey R.
• Application Number:
  US09/269,818
• Time in Patent Office: 551 Days
• Field of Search: 607/9, 607/17, 607/25
• US Class Current: 607/9
• CPC Class Codes: A61N 1/365 controlled by a physiological parameter, e.g. heart potential evoked response A61N1/371

Abstract

An implantable stimulating device for electrical stimulation of a heart has a stimulus generator which generates electrical stimuli and at least one lead for delivering the stimuli from the generator to the heart. A measurement unit detects spontaneous intervals between successive intrinsic heartbeats, and forms an average of at least five of these spontaneous intervals. A variation with respect to this average for later spontaneous intervals is then identified, and this variation is then used to control a pacing parameter of the stimulus generator.

Claims

1. An implantable stimulating device for electrical stimulation of a heart, comprising:

a stimulus generator which generates electrical pacing stimuli;

at least one lead connected to said stimulus generator and adapted to deliver said pacing stimuli from said stimulus generator to a heart;

measuring means connected to said lead for measuring respective spontaneous intervals between successive intrinsic heartbeats and for identifying a variation of an average of at least five latest spontaneous intervals of said spontaneous intervals; and

a control unit supplied with said variation from said measuring means for controlling a pacing control parameter of said stimulus generator dependent on said variation.

3. A stimulating device according to claim 1 wherein said control parameter controls a hysteresis interval of said placing stimuli.

4. A stimulating device according to claim 1 wherein said control parameter controls a maximum stimulation rate.

5. A stimulating device according to claim 1 wherein said measuring means comprises a detector connected to the connection lead which detects said time interval, a memory connected to said detector for storing a predetermined number of latest detected time intervals, and a calculator for calculating and producing signals representative of the spontaneous interval variation, said calculator using said latest detected time intervals.

6. A stimulating device as claimed in claim 1 wherein said measuring means calculates said time interval variation by determining a difference between a largest value and a smallest value of a predetermined number of said time intervals.

7. A stimulating device according to claim 1 said measuring means calculates said timer interval variation by determining a variance of a predetermined number of said time intervals.

2. A stimulating device according to claim 9 wherein said control parameter is controlled in dependence from the value of only said time interval variation.