US 5,395,396 AGranted

Method and apparatus for stimulating a heart

AssigneeSiemens Elema AB

InventorsAnders Lindgren, Per Franberg

Life of this patent

Estimating the term…

Loading patent…

Abstract

A heart stimulator is disclosed which is capable of sensing and stimulating both the atrium and the ventricle in a heart such that a ventricular stimulation pulse is emitted, either after expiration of an atrioventricular interval following a stimulated or spontaneous atrial event, or after expiration of a minimum synchronous interval following a stimulated or spontaneous ventricular event, depending on which of the two intervals expires last. After each ventricular event, an atrial refractory period is imposed during which atrial detections are interpreted as noise. Operation of the heart stimulator when the atrium's spontaneous rate is faster than a stimulation rate corresponding to the minimum synchronous interval is improved by measuring the interval between atrial events. If a detection during the atrium's refractory period occurs at a time corresponding to the latest interval timed, the detection is interpreted as an approved atrial event, and a ventricular stimulation pulse is emitted after expiration of the minimum synchronous interval.

Claims18

Dependent claims

A method for electrically stimulating a heart comprising the steps of:

(a) detecting spontaneous and stimulated cardiac events in each of the atrium and the ventricle of a heart;
(b) delivering a series of atrial stimulation pulses to said atrium at a programmable basic interval;
(c) inhibiting delivery of an atrial stimulation pulse if a spontaneous atrial event is detected during said basic interval;
(d) delivering a ventricular stimulation pulse after expiration of an atrioventricular interval following each inhibited or stimulated atrial pulse or a spontaneous atrial event, or after expiration of a minimum synchronous interval following a stimulated or spontaneous ventricular event, dependent on which of said atrioventricular interval or said minimum synchronous interval elapses last;
(e) setting a refractory period following each ventricular stimulation pulse during which detection of an atrial event is normally interpreted as noise rather than as an atrial event;
(f) measuring and updating each interval between consecutive atrial events which are spontaneous atrial events;
(g) monitoring the interval between consecutive atrial events of any type and, if said interval between successive atrial events of any type is less than said minimum synchronous interval, interpreting an atrial event, occurring at a time lapse after a latest atrial event which corresponds to a latest interval between spontaneous atrial events, as an atrial event;
(h) delivering a next ventricular pulse after said minimum synchronous interval expires;
and
(i) repeating steps (f), (g) and (h) until said interval between consecutive atrial events of any type exceeds said minimum synchronous interval, and thereafter returning to step (b).

7 more elements

An apparatus for electrically stimulating a heart comprising the steps of:

means for detecting spontaneous and stimulated cardiac events in each of the atrium and the ventricle of a heart;
means for delivering a series of atrial stimulation pulses to said atrium at a programmable basic interval;
a control unit including means for inhibiting delivery of an atrial stimulation pulse if a spontaneous atrial event is detected during said basic interval;
said control unit further including means for causing delivery of a ventricular stimulation pulse after expiration of an atrioventricular interval following each inhibited or stimulated atrial pulse or a spontaneous atrial event, or after expiration of a minimum synchronous interval following a stimulated or spontaneous ventricular event, dependent on which of said atrioventricular interval or said minimum synchronous interval elapses last;
said control unit further including means for setting a refractory period following each ventricular stimulation pulse during which detection of an atrial event is normally interpreted as noise rather than as an atrial event;
said control unit further including means for measuring and updating each interval between consecutive atrial events which are spontaneous atrial events;
said control unit including means for monitoring the interval for between consecutive atrial events of any type, and if said interval between successive atrial events of any type is less than said minimum synchronous interval, for interpreting an atrial event, occurring at a time lapse after a latest atrial event which corresponds to a latest interval between spontaneous atrial events, as an atrial event and for delivering a next ventricular pulse after said minimum synchronous interval expires, until said interval between consecutive atrial events of any type exceeds said minimum synchronous interval.

4 more elements

Dependencies are inferred from the claim text.