Reducing inappropriate delivery of therapy for suspected non-lethal arrhythmias
First Claim
1. A method of determining a status of a ventricular rhythm of a heart using an implantable medical device comprising a sensing electrode, a therapy electrode and a processor, comprising the steps of:
- measuring a ventricular cycle length of a ventricular rhythm of a heart detected by said sensing electrode;
comparing with the processor a number of times the ventricular cycle length exceeds a ventricular cycle length threshold against a predetermined number of intervals to detect threshold (NID threshold) to obtain a comparison;
thendetermining, with the processor and based on the comparison, if the ventricular rhythm is a lethal arrhythmia or a non-lethal arrhythmia; and
thenif the ventricular rhythm is a lethal arrhythmia, delivering a therapy to the heart using the therapy electrode;
if the ventricular rhythm is a non-lethal arrhythmia, withholding the therapy to the heart and increasing the NID threshold;
thenmeasuring a subsequent ventricular cycle length of the ventricular rhythm of the heart detected by said sensing electrode;
comparing with the processor an updated number of times the ventricular cycle length and the subsequent ventricular cycle length exceed the ventricular cycle length threshold against the NID threshold, as updated, to obtain an update of the comparison, the updated number of times additively incorporating an instance of the subsequent ventricular cycle length exceeding the ventricular cycle length threshold;
thenreturning to the determining step; and
wherein the NID threshold is reset to the predetermined NID threshold by the processor upon a first predetermined condition and the number of times the ventricular cycle length exceeds a ventricular cycle length threshold is reset upon a second predetermined condition.
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Accused Products
Abstract
An implantable medical device (IMD) identifies suspected non-lethal ventricular arrhythmia, and takes one or more actions in response to the identification to avoid or delay delivery of a defibrillation or cardioversion shock. The IMD employs number of intervals to detect (NID) thresholds for detection of ventricular arrhythmias. When a NID threshold is met, the IMD determines whether the ventricular rhythm is a suspected non-lethal rhythm despite satisfying a NID threshold. In some embodiments, the IMD increases the NID threshold, i.e., extends the time for detection, in response to identifying a rhythm as a suspected non-lethal rhythm, and monitors subsequent ventricular beats to determine if the increased NID threshold is met before detecting a ventricular arrhythmia and delivering therapy. The IMD can determine whether a rhythm is a suspected non-lethal arrhythmia by, for example, comparing the median ventricular cycle length (VCL) to the median atrial cycle length (ACL).
36 Citations
51 Claims
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1. A method of determining a status of a ventricular rhythm of a heart using an implantable medical device comprising a sensing electrode, a therapy electrode and a processor, comprising the steps of:
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measuring a ventricular cycle length of a ventricular rhythm of a heart detected by said sensing electrode; comparing with the processor a number of times the ventricular cycle length exceeds a ventricular cycle length threshold against a predetermined number of intervals to detect threshold (NID threshold) to obtain a comparison;
thendetermining, with the processor and based on the comparison, if the ventricular rhythm is a lethal arrhythmia or a non-lethal arrhythmia; and
thenif the ventricular rhythm is a lethal arrhythmia, delivering a therapy to the heart using the therapy electrode; if the ventricular rhythm is a non-lethal arrhythmia, withholding the therapy to the heart and increasing the NID threshold;
thenmeasuring a subsequent ventricular cycle length of the ventricular rhythm of the heart detected by said sensing electrode; comparing with the processor an updated number of times the ventricular cycle length and the subsequent ventricular cycle length exceed the ventricular cycle length threshold against the NID threshold, as updated, to obtain an update of the comparison, the updated number of times additively incorporating an instance of the subsequent ventricular cycle length exceeding the ventricular cycle length threshold;
thenreturning to the determining step; and wherein the NID threshold is reset to the predetermined NID threshold by the processor upon a first predetermined condition and the number of times the ventricular cycle length exceeds a ventricular cycle length threshold is reset upon a second predetermined condition. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An implantable medical device for a patient having a heart which generates a ventricular rhythm, comprising:
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a sensing electrode sensitive to the ventricular rhythm; a therapy electrode configured to deliver a therapy to the heart; a processor, operatively coupled to the sensing electrode and the therapy electrode, configured to; measure a ventricular cycle length of the ventricular rhythm; compare a number of times the ventricular cycle length exceeds a ventricular cycle length threshold against a predetermined number of intervals to detect threshold (NID threshold) to obtain a comparison;
then perform a determine operation, based on the comparison, comprising determining if the ventricular rhythm is a lethal arrhythmia or a non-lethal arrhythmia; andthen if a lethal arrhythmia, deliver a therapy to the heart with the therapy electrode; if a non-lethal arrhythmia, withhold the therapy to the heart and increase the NID threshold;
thenmeasure a subsequent ventricular cycle length of the ventricular rhythm of the heart; compare an updated number of times the ventricular cycle length and the subsequent ventricular cycle length exceed the ventricular cycle length threshold against the NID threshold, as updated, to obtain an update of the comparison, the updated number of times additively incorporating an instance of the subsequent ventricular cycle length that exceeds the ventricular cycle length threshold;
thenreturn to the determine operation; and wherein the processor resets the NID threshold to the predetermined NID threshold upon a first predetermined condition and the number of times the ventricular cycle length exceeds a ventricular cycle length threshold is reset upon a second predetermined condition. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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43. An implantable medical device for determining a status of a ventricular rhythm of a heart, comprising:
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means for measuring a ventricular cycle length of a ventricular rhythm of a heart; means for comparing a number of times the ventricular cycle length exceeds a ventricular cycle length threshold against a predetermined number of intervals to detect threshold (NID threshold) to obtain a comparison; means for determining, based on the comparison, if the ventricular rhythm is a lethal arrhythmia or a non-lethal arrhythmia; means for delivering a therapy to the heart if the ventricular rhythm is a lethal arrhythmia,; means for withholding the therapy to the heart and increasing the NID threshold if the ventricular rhythm is a non-lethal arrhythmia; means for measuring a subsequent ventricular cycle length of the ventricular rhythm of the heart; means for comparing an updated number of times the ventricular cycle length and the subsequent ventricular cycle length exceed the ventricular cycle length threshold against the NID threshold, as updated, to obtain an update of the comparison, the updated number of times additively incorporating an instance of the subsequent ventricular cycle length that exceeds the ventricular cycle length threshold; means for returning to the means for determining; and wherein the NID threshold is reset to the predetermined NID threshold upon a first predetermined condition and the number of times the ventricular cycle length exceeds a ventricular cycle length threshold is reset upon a second predetermined condition. - View Dependent Claims (44, 45, 46, 47, 48, 49, 50, 51)
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Specification