Heart rhythm classification method, and implantable dual chamber cardioverter/defibrillator employing the same
First Claim
1. A method for monitoring and classifying cardiac rhythms of a patient'"'"'s heart, comprising the steps of:
- sensing atrial and ventricular events of the heart;
timing A-A intervals between said atrial events and V-V intervals between said ventricular events;
determining A/V interval ratios which comprise ratios of said A-A intervals to said V-V intervals; and
responsive to said sensed events, classifying said rhythms,said classifying step including the sub-steps of (i) providing a first threshold establishing a V-V interval level below which sensed heart rhythms are classified as treatable tachycardia, (ii) providing a second threshold above which sensed heart rhythms are classified as not tachycardia, said first and second thresholds defining therebetween a band of V-V intervals which includes heart rhythms that comprise both non-treatable tachycardias and treatable tachycardias, (iii) providing a third threshold in said band establishing an A/V ratio below which sensed heart rhythms have A-A intervals which are shorter than the V-V intervals thereof and are classified as non-treatable tachycardias, and (iv) providing a fourth threshold establishing an A/V interval ratio above which sensed heart rhythms have V-V intervals which are shorter than the A-A intervals thereof and are classified as treatable tachycardias, said third and fourth thresholds defining therebetween a middle region wherein said A-A intervals and said V-V intervals are approximately the same,said classifying step including a further sub-step, responsive to those heart rhythms that fall within said middle region, of discriminating further among said heart rhythms in said middle region in order to classify said rhythms into non-treatable tachycardias and treatable tachycardias.
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Accused Products
Abstract
An implantable dual chamber ICD and method senses atrial (A-A) and ventricular (V-V) intervals, calculates the ratio (A/V interval ratio) of A-A intervals to V-V intervals, classifies heart rhythms with V-V intervals (i) above a revert rate threshold as not tachycardia, (ii) below a high rate threshold as treatable tachycardia, (iii) between the two thresholds and below an A-dominant A/V interval ratio threshold as a non-treatable tachycardia, (iv) between the revert rate threshold and the high rate threshold and above a V-dominant threshold as treatable tachycardia and, when the heart rhythm is intermediate all four thresholds, (v) utilizes one or a combination of advanced discriminators (e.g., ventricular windowing, ventricular interval variability, sudden onset, AV-delay creep, ventricular electrogram morphology, active sensing, minute ventilation, or right ventricular pressure) to classify whether the heart rhythm is a non-treatable or a treatable tachycardia.
277 Citations
8 Claims
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1. A method for monitoring and classifying cardiac rhythms of a patient'"'"'s heart, comprising the steps of:
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sensing atrial and ventricular events of the heart; timing A-A intervals between said atrial events and V-V intervals between said ventricular events; determining A/V interval ratios which comprise ratios of said A-A intervals to said V-V intervals; and responsive to said sensed events, classifying said rhythms, said classifying step including the sub-steps of (i) providing a first threshold establishing a V-V interval level below which sensed heart rhythms are classified as treatable tachycardia, (ii) providing a second threshold above which sensed heart rhythms are classified as not tachycardia, said first and second thresholds defining therebetween a band of V-V intervals which includes heart rhythms that comprise both non-treatable tachycardias and treatable tachycardias, (iii) providing a third threshold in said band establishing an A/V ratio below which sensed heart rhythms have A-A intervals which are shorter than the V-V intervals thereof and are classified as non-treatable tachycardias, and (iv) providing a fourth threshold establishing an A/V interval ratio above which sensed heart rhythms have V-V intervals which are shorter than the A-A intervals thereof and are classified as treatable tachycardias, said third and fourth thresholds defining therebetween a middle region wherein said A-A intervals and said V-V intervals are approximately the same, said classifying step including a further sub-step, responsive to those heart rhythms that fall within said middle region, of discriminating further among said heart rhythms in said middle region in order to classify said rhythms into non-treatable tachycardias and treatable tachycardias. - View Dependent Claims (2, 3, 4)
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5. An implantable dual chamber cardioverter/defibrillator device for monitoring and classifying cardiac rhythms of a patient'"'"'s heart, comprising:
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means adapted to be coupled to the atrium and ventricle of the heart for sensing atrial and ventricular events thereof, said sensing means including means for timing A-A intervals between said atrial events and V-V intervals between said ventricular events, and said sensing means further including means for determining A/V interval ratios which comprise ratios of said A-A intervals to said V-V intervals; means operatively connected to said sensing means and responsive thereto for classifying said rhythms, said classifying means including (i) a first threshold establishing a V-V interval level below which sensed heart rhythms are classified as treatable tachycardia, (ii) a second threshold level above which sensed heart rhythms are classified as not tachycardia, said first and second thresholds defining therebetween a band of V-V intervals which includes heart rhythms that comprise both non-treatable tachycardias and treatable tachycardias, (iii) a third threshold in said band establishing an A/V interval ratio below which sensed heart rhythms have A-A intervals which are shorter than the V-V intervals thereof and are classified as non-treatable tachycardias, and (iv) a fourth threshold establishing an A/V interval ratio above which sensed heart rhythms have V-V intervals which are shorter than the A-A intervals thereof and are classified as treatable tachycardias, said third and fourth thresholds defining therebetween a middle region wherein said A-A intervals and said V-V intervals are approximately the same, said classifying means further including discriminating means responsive to those heart rhythms that fall within said middle region for classifying said heart rhythms into non-treatable tachycardias and treatable tachycardias. - View Dependent Claims (6, 7, 8)
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Specification