Method and apparatus for discrimination atrial fibrillation using ventricular rate detection
First Claim
1. A method for discriminating heart rhythms in an implantable medical device, comprising the steps of:
- receiving a QRS interval corresponding to the heart rhythm and computing a first predetermined number of RR intervals from the received QRS intervals;
computing a median RR interval corresponding to a predetermined number of the first predetermined number of RR intervals;
determining a rate zone in response to the computed median RR interval;
determining a predetermined beat-to-beat variation corresponding to the rate zone;
varying a count in response to the rate zone and the predetermined beat-to-beat variation;
computing beat-to-beat variation differences between the first predetermined number of RR intervals;
comparing the beat-to-beat variation differences to the predetermined beat-to-beat variation to determine whether the number of the computed beat-to-beat variation differences greater than the predetermined beat-to-beat variation is greater than the count; and
identifying the heart rhythm in response to the number of the computed beat-to-beat variation differences relative to the count.
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Accused Products
Abstract
A method and apparatus for method for discriminating heart rhythms includes computing a first predetermined number of RR intervals from received QRS intervals, and computing a median RR interval corresponding to a predetermined number of the first predetermined number of RR intervals. A predetermined beat-to-beat variation and a corresponding predetermined count are determined based on the computed median RR interval. Beat-to-beat variation differences between the first predetermined number of RR intervals are computed and a determination is made as to whether the computed beat-to-beat variation differences are greater than the predetermined beat-to-beat variation, and as to whether a number of the computed beat-to-beat variation differences that are greater than the predetermined beat-to-beat variation is greater than the predetermined count. The heart rhythm is identified as an irregular rhythm in response to the number being greater than or equal to the predetermined count.
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Citations
16 Claims
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1. A method for discriminating heart rhythms in an implantable medical device, comprising the steps of:
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receiving a QRS interval corresponding to the heart rhythm and computing a first predetermined number of RR intervals from the received QRS intervals;
computing a median RR interval corresponding to a predetermined number of the first predetermined number of RR intervals;
determining a rate zone in response to the computed median RR interval;
determining a predetermined beat-to-beat variation corresponding to the rate zone;
varying a count in response to the rate zone and the predetermined beat-to-beat variation;
computing beat-to-beat variation differences between the first predetermined number of RR intervals;
comparing the beat-to-beat variation differences to the predetermined beat-to-beat variation to determine whether the number of the computed beat-to-beat variation differences greater than the predetermined beat-to-beat variation is greater than the count; and
identifying the heart rhythm in response to the number of the computed beat-to-beat variation differences relative to the count. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for discriminating between heart rhythms in an implantable medical device, comprising the steps of:
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computing a first predetermined number of RR intervals from received QRS intervals;
computing a median RR interval corresponding to a predetermined number of the first predetermined number of RR intervals;
determining a rate zone in response to the computed median RR interval;
determining a predetermined beat-to-beat variation and varying a predetermined count in response to the rate zone and the predetermined beat-to-beat variation;
computing beat-to-beat variation differences between the first predetermined number of RR intervals;
determining whether the computed beat-to-beat variation differences are greater than the predetermined beat-to-beat variation; and
determining whether a number of the computed beat-to-beat variation differences that are greater than the predetermined beat-to-beat variation is greater than the predetermined count;
identifying the heart rhythm as an irregular rhythm in response to the number being greater than or equal to the predetermined count; and
identifying the heart rhythm as a regular rhythm in response to the number being less than the predetermined count. - View Dependent Claims (8, 9, 10)
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11. An implantable medical device, comprising:
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sensing means for sensing cardiac activity of a patient;
first detector means for computing a median RR interval in response to a predetermined number of RR intervals associated with the sensed cardiac activity, determining a rate zone in response to the computed median RR interval, determining a variation associated with the determined rate zone, varying a count in response to the rate zone and the variation, computing variation differences between intervals of the predetermined number of intervals, determining whether the number of the computed variation differences that are greater than the determine variation is greater than the count, and outputting a signal in response to the determined number of the computed variation differences relative to the count; and
trigger means for receiving the signal from the detector means and initiating storage of the sensed cardiac activity. - View Dependent Claims (12, 13, 14, 15, 16)
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Specification