Tachyarrhythmia detection method
First Claim
1. A method for detecting cardiac arrhythmias, including the steps of:
- detecting a patient'"'"'s cardiac activity and initiating a tachyarrhythmia detection period upon detecting that the cardiac activity satisfies a first selected tachyarrhythmia criterion;
counting the number of intervals which satisfy a second selected tachyarrhythmia criterion, and producing a sinus interval history count indicative of the number of such intervals which are counted;
terminating the tachyarrhythmia detection period and making a preliminary diagnosis of tachyarrhythmia upon detecting that the cardiac activity satisfies a third selected tachyarrhythmia criterion; and
,making a final diagnosis of tachyarrhythmia if the sinus interval history count is less than a selected maximum sinus interval history count, and otherwise, inhibiting a final diagnosis of tachyarrhythmia.
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Abstract
A method for detecting cardiac arrhythmias which includes the steps of detecting a patient'"'"'s cardiac activity, counting the number of intervals which satisfy a first selected criterion, and producing a sinus interval history count indicative of the number of such intervals which are counted, making a preliminary diagnosis of tachyarrhythmia upon detecting that the cardiac activity satisfies a second selected criterion, and, making a final diagnosis of tachyarrhythmia if the sinus interval history count is less than a selected maximum sinus interval history count, and otherwise, inhibiting a final diagnosis of tachyarrhythmia. In an alternative embodiment, the method for detecting cardiac arrhythmias includes the steps of detecting a patient'"'"'s cardiac activity, counting the number of intervals which satisfy a first selected criterion, and producing a sinus interval history count indicative of the number of such intervals which are counted, making a preliminary diagnosis of tachyarrhythmia upon detecting that the cardiac activity satisfies a second selected criterion, determining if the preliminary diagnosis of tachyarrhythmia is proper according to a first measure of interval irregularity, making a qualified preliminary diagnosis of tachyarrhythmia if it is determined that the preliminary diagnosis of tachyarrhythmia is proper according to the first measure of interval irregularity, and otherwise, inhibiting a final diagnosis of tachyarrhythmia, and, if a qualified preliminary diagnosis of tachyarrhythmia is made, then making a final diagnosis of tachyarrhythmia if the sinus interval history count is less than a selected maximum sinus interval history count, and otherwise, inhibiting a final diagnosis of tachyarrhythmia. The invention also includes a cardiac therapy device, e.g., an implantable cardioverter-defibrillator (ICD), programmed to implement the tachyarrhythmia detection method of the present invention.
158 Citations
17 Claims
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1. A method for detecting cardiac arrhythmias, including the steps of:
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detecting a patient'"'"'s cardiac activity and initiating a tachyarrhythmia detection period upon detecting that the cardiac activity satisfies a first selected tachyarrhythmia criterion; counting the number of intervals which satisfy a second selected tachyarrhythmia criterion, and producing a sinus interval history count indicative of the number of such intervals which are counted; terminating the tachyarrhythmia detection period and making a preliminary diagnosis of tachyarrhythmia upon detecting that the cardiac activity satisfies a third selected tachyarrhythmia criterion; and
,making a final diagnosis of tachyarrhythmia if the sinus interval history count is less than a selected maximum sinus interval history count, and otherwise, inhibiting a final diagnosis of tachyarrhythmia. - View Dependent Claims (2, 3, 4, 5)
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6. A method for detecting cardiac arrhythmias, including the steps of:
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detecting a patient'"'"'s cardiac activity and initiating a tachyarrhythmia detection period upon detecting that the cardiac activity satisfies a first selected tachyarrhythmia criterion; counting the number of intervals which satisfy a second selected tachyarrhythmia criterion, and producing a sinus interval history count indicative of the number of such intervals which are counted; terminating the tachyarrhythmia detection period and making a preliminary diagnosis of tachyarrhythmia upon detecting that the cardiac activity satisfies a third selected tachyarrhythmia criterion; determining if the preliminary diagnosis of tachyarrhythmia is proper according to a first measure of interval irregularity; making a qualified preliminary diagnosis of tachyarrhythmia if it is determined that the preliminary diagnosis of tachyarrhythmia is proper according to the first measure of interval irregularity, and otherwise, inhibiting a final diagnosis of tachyarrhythmia; and
,if a qualified preliminary diagnosis of tachyarrhythmia is made, then making a final diagnosis of tachyarrhythmia if the sinus interval history count is less than a selected maximum sinus interval history count, and otherwise, inhibiting a final diagnosis of tachyarrhythmia. - View Dependent Claims (7, 8, 9, 10)
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11. A method for detecting cardiac arrhythmias, comprising the steps of:
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monitoring an electrogram representative of a patient'"'"'s cardiac activity including a sequence of cardiac events; in response to the monitoring step, sensing intervals between successive cardiac events; at every interval, determining the duration of that interval and computing the average duration of a prescribed number of preceding intervals, including that interval, and classifying that interval as either a countable tachyarrhythmia interval or a countable sinus interval, based upon the determined duration of that interval and the computed average duration associated with that interval, and further classifying that interval as an absolute sinus interval if either the duration of that interval or the computed average duration associated with that interval is greater than a prescribed duration threshold; counting the number of absolute sinus intervals; counting the number of countable tachyarrhythmia intervals and countable sinus intervals; making a preliminary diagnosis of tachyarrhythmia if the counted number of countable tachyarrhythmia intervals exceeds a prescribed maximum tachyarrhythmia count before the counted number of countable sinus intervals exceeds a prescribed maximum sinus interval count; and
,making a final diagnosis of tachyarrhythmia if the counted number of absolute sinus intervals is less than a prescribed maximum absolute sinus interval count, and otherwise, inhibiting diagnosis of tachyarrhythmia. - View Dependent Claims (12)
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13. A method for detecting cardiac arrhythmias, comprising the steps of:
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monitoring an electrogram representative of a patient'"'"'s cardiac activity including a sequence of cardiac events; in response to the monitoring step, sensing intervals between successive cardiac events; at every interval, determining the duration of that interval and computing the average duration of a prescribed number of preceding intervals, including that interval; initiating a detection period upon detecting that the computed average duration is less than a prescribed average duration threshold; at every interval after initiation of the detection period, classifying that interval as either a countable tachyarrhythmia interval or a countable sinus interval, based upon the determined duration of that interval and the computed average duration associated with that interval, and further classifying that interval as an absolute sinus interval if either the duration of that interval or the computed average duration associated with that interval is greater than a prescribed duration threshold; counting the number of absolute sinus intervals; counting the number of countable tachyarrhythmia intervals and countable sinus intervals; terminating the detection period and making a preliminary diagnosis of tachyarrhythmia if the counted number of countable tachyarrhythmia intervals exceeds a prescribed maximum tachyarrhythmia count before the counted number of countable sinus intervals exceeds a prescribed maximum sinus interval count; and
,making a final diagnosis of tachyarrhythmia if the counted number of absolute sinus intervals during the detection period is less than a prescribed maximum absolute sinus interval count, and otherwise, inhibiting diagnosis of tachyarrhythmia.
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14. A method for detecting cardiac arrhythmias, comprising the steps of:
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monitoring an electrogram representative of a patient'"'"'s cardiac activity including a sequence of cardiac events; in response to the monitoring step, sensing intervals between successive cardiac events; at every interval, determining the duration of that interval and computing the average duration of a prescribed number of preceding intervals, including that interval, and classifying that interval as either a countable tachyarrhythmia interval or a countable sinus interval, based upon the determined duration of that interval and the computed average duration associated with that interval, and further classifying that interval as an absolute sinus interval if either the duration of that interval or the computed average duration associated with that interval is greater than a prescribed duration threshold; counting the number of absolute sinus intervals; counting the number of countable tachyarrhythmia intervals and countable sinus intervals; determining if the preliminary diagnosis of tachyarrhythmia is proper according to a first measure of interval irregularity; making a qualified preliminary diagnosis of tachyarrhythmia if it is determined that the preliminary diagnosis of tachyarrhythmia is proper according to the first measure of interval irregularity, and otherwise, inhibiting a final diagnosis of tachyarrhythmia; and
,if a qualified preliminary diagnosis of tachyarrhythmia is made, then making a final diagnosis of tachyarrhythmia if the counted number of absolute sinus intervals during the tachyarrhythmia detection period is less than a selected maximum sinus interval count, and otherwise, inhibiting a final diagnosis of tachyarrhythmia.
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15. A method for detecting cardiac arrhythmias, comprising the steps of:
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detecting a patient'"'"'s cardiac activity; counting the number of intervals which satisfy a first selected tachyarrhythmia criterion, and producing a sinus interval history count indicative of the number of such intervals which are counted; making a preliminary diagnosis of tachyarrhythmia upon detecting that the cardiac activity satisfies a second selected tachyarrhythmia criterion; and
,making a final diagnosis of tachyarrhythmia if the sinus interval history count is less than a selected maximum sinus interval history count, and otherwise, inhibiting a final diagnosis of tachyarrhythmia. - View Dependent Claims (16)
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17. A method of discriminating between supraventricular tachycardia and ventricular tachycardia comprising the steps of:
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detecting a patient'"'"'s cardiac activity and measuring successive cardiac interval durations; comparing each cardiac interval to a selected tachycardia threshold and identifying an interval as a tachycardia interval if its duration is less than the tachycardia threshold; initiating a tachycardia detection period upon identifying a tachycardia interval; for each interval during said tachycardia detection period, computing the average duration of a selected number of intervals, including that interval; during said tachycardia detection period counting the number of intervals which have a duration greater than the selected tachycardia threshold or for which the computed average duration is greater the selected tachycardia threshold, to produce a sinus interval history count indicative of the number of such intervals which are counted; terminating said tachycardia detection period when a selected number of tachycardia intervals have been detected; and diagnosing a ventricular tachycardia if said sinus interval history count is less than a selected sinus interval history count threshold and diagnosing a supraventricular tachycardia if said sinus interval history count is greater than or equal to said selected sinus interval history count threshold.
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Specification