US 5,462,060 AGranted

Methods and apparatus for determining when tachyarrythmia is pace-terminable

AssigneeELA Medical S.A.

InventorsPeter Jacobson, Daniel Kroiss, Christine Henry

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Abstract

Methods and apparatus for classifying cardiac rhythm by analyzing sensed atrial and ventricular heartbeats, and determining if the rhythm might be pace-terminable in a given chamber. The method maintains a histogram of the sensed beat interval in the chamber of interest and a second histogram of conduction time from the other chamber. The method classifies a rhythm as pace terminable in the given chamber when the intervals in that chamber are stable, and the conduction times to that chamber are unstable. It applies further criteria when the intervals in the given chamber are stable, and the conduction times are also stable. Antitachycardia pacing is deliverable to terminate tachyarrhythmias determined to be pace terminable.

Claims81

Dependent claims

A method of analyzing a patient's cardiac activity comprising the steps of:

(a) detecting cardiac events in the atrium and the ventricle;
(b) determining an interval between each detected event in a first chamber, each interval having a time length, said first chamber being one of the atrium and the ventricle;
(c) determining a conduction interval between a sensed cardiac event in the first chamber and a preceding sensed cardiac event in the second chamber, each conduction interval having a time length, the second chamber being the other of the atrium and ventricle;
(d) forming an auto-correlation histogram of determined intervals in said first chamber corresponding to a cardiac cycle in the first chamber that is above a sinus rhythm;
(e) forming a cross-correlation histogram of determined conduction intervals corresponding to a cardiac cycle in the first chamber that is above a sinus rhythm;
(f) processing the auto-correlation histogram by
(i) scanning the auto-correlation histogram with a stability window, determining the number of intervals in the stability window for each position of the stability window in the auto-correlation histogram, and determining the maximum number of intervals within said stability window of all of the possible positions of the stability window,
(ii) determining an auto-correlation peak count as said determined maximum number of intervals that satisfy the stability window, and
(iii) providing an auto-correlation total corresponding to the number of the determined intervals in the auto-correlation histogram;
(g) processing the cross-correlation histogram by
(i) scanning the cross-correlation histogram with a conduction time window, determining the number of intervals in the conduction time window for each position of the conduction time window in the cross-correlation histogram and determining the maximum number of determined conduction intervals within said conduction time window of all of the possible positions of said conduction time window,
(ii) determining a cross-correlation peak count as the determined number of maximum determined conduction intervals that satisfy the conduction time window, and
(iii) providing a cross-correlation total corresponding to the number of the determined conduction intervals in the cross-correlation histogram;
and
(h) determining whether the patient's cardiac events correspond to a tachyarrhythmia that is terminable by a stimulation pulse in the first chamber based on the determined auto-correlation peak and the determined cross-correlation peak.

12 more elements

A method of analyzing a patient's cardiac activity comprising the steps of:

(a) sensing cardiac events in the atrium and the ventricle;
(b) processing the sensed cardiac events including the steps of
(i) determining an interval between each detected event in a first chamber corresponding to a cardiac cycle, each interval having a time length, said first chamber being one of the atrium and the ventricle;
(ii) selecting the determined intervals corresponding to a plurality of cardiac cycles above a sinus rhythm, providing a first total as a count of said selected determined intervals and determining whether said determined intervals satisfy a stability criterion;
(iii) determining a first peak count of the determined intervals that satisfy said stability criterion;
(iv) determining a conduction interval between a sensed cardiac event in the first chamber and each preceding sensed cardiac event in the second chamber for the plurality of cardiac cycles, each conduction interval having a time length, the second chamber being the other of the atrium and ventricle, and providing a second total as a count of said determined conduction intervals;
(v) determining whether each conduction interval time length is within a conduction time stability criterion;
and
(vi) determining a second peak count of the determined conduction intervals that are within the conduction time stability criterion;
and
(c) determining whether the patient's processed cardiac events correspond to a tachyarrhythmia that is terminable by a stimulation pulse in the first chamber based on the determined first and second peaks.

8 more elements

Apparatus for analyzing a patient's cardiac activity comprising:

means for sensing cardiac events in the atrium and the ventricle;
means for processing the sensed cardiac events comprising
first means for determining an interval between each detected event corresponding to a cardiac cycle in a first chamber, each interval having a time length, said first chamber being one of the atrium and the ventricle;
second means for selecting the determined intervals above a sinus rhythm and corresponding to a plurality of cardiac cycles, determining whether the selected determined intervals satisfy a stability criterion;
third means for determining a first peak count of the selected determined intervals that satisfy said stability criterion;
first count means for providing a first total of the number of selected determined intervals;
fourth means for determining a conduction interval between a sensed cardiac event in the first chamber and each preceding sensed cardiac event in the second chamber for the plurality of cardiac cycles, each determined conduction interval having a time length, the second chamber being the other of the atrium and ventricle;
fifth means for determining whether each determined conduction interval time length is within a conduction time stability criterion;
sixth means for determining a second peak count of the determined conduction intervals that are within the conduction time stability criterion;
and
second count means for providing a second total as a count of said determined conduction intervals;
and
seventh means for determining whether the patient's processed cardiac events correspond to a tachyarrhythmia that is terminable by a stimulation pulse in the first chamber based on the determined first and second peaks.

10 more elements

Dependencies are inferred from the claim text.