Algorithm for discrimination of 1:1 tachycardias
First Claim
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1. A cardiac rhythm management device, comprising:
- an atrial sensing channel for detecting atrial senses corresponding to atrial depolarizations;
a ventricular sensing channel for detecting ventricular senses corresponding to ventricular depolarizations;
a controller for detecting arrhythmias based upon the atrial and ventricular senses detected in the sensing channels, wherein the controller is programmed to;
compute an AA interval corresponding to a cycle length between consecutive atrial senses, a VV interval corresponding to a cycle length between consecutive ventricular senses, an AV interval corresponding to a cycle length between an atrial sense and a next occurring ventricular sense with no intervening atrial sense, and a VA interval corresponding to a cycle length between a ventricular sense and a next occurring atrial sense with no intervening ventricular sense;
compute variabilities for both the VA and AV intervals based upon their measured individual cycle lengths during a specified time window;
detect a supraventricular tachycardia (SVT) when;
(a) the AA interval is within a tachycardia range defined as below an SVT threshold and (b) the VV interval is within normal limits;
detect a ventricular fibrillation (VF) when the VV interval is below a VF threshold;
detect a ventricular tachycardia (VT) when;
(a) the VV interval is within a tachycardia range defined as above the VF threshold but below a VT threshold and (b) the AA interval is either within normal limits or differs from the VV interval by more than a specified dual tachycardia limit value; and
, if a 1;
1 tachycardia condition is present, defined as when the AA and VV intervals are both within their tachycardia ranges and differ from one another by no more than a specified 1;
1 limit value, discriminate between a supraventricular tachycardia and a ventricular tachycardia based upon a relative variability of the VA and AV intervals.
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Abstract
An algorithm for detection of tachycardias and for discriminating between supraventricular tachycardia (SVT) and ventricular tachycardia (VT) when a 1:1 tachycardia condition is present that can be implemented in an implantable cardiac rhythm management device. Variability measures of AV and VA intervals during the tachycardia are computed and used to distinguish between SVT and VT.
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Citations
26 Claims
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1. A cardiac rhythm management device, comprising:
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an atrial sensing channel for detecting atrial senses corresponding to atrial depolarizations;
a ventricular sensing channel for detecting ventricular senses corresponding to ventricular depolarizations;
a controller for detecting arrhythmias based upon the atrial and ventricular senses detected in the sensing channels, wherein the controller is programmed to;
compute an AA interval corresponding to a cycle length between consecutive atrial senses, a VV interval corresponding to a cycle length between consecutive ventricular senses, an AV interval corresponding to a cycle length between an atrial sense and a next occurring ventricular sense with no intervening atrial sense, and a VA interval corresponding to a cycle length between a ventricular sense and a next occurring atrial sense with no intervening ventricular sense;
compute variabilities for both the VA and AV intervals based upon their measured individual cycle lengths during a specified time window;
detect a supraventricular tachycardia (SVT) when;
(a) the AA interval is within a tachycardia range defined as below an SVT threshold and (b) the VV interval is within normal limits;
detect a ventricular fibrillation (VF) when the VV interval is below a VF threshold;
detect a ventricular tachycardia (VT) when;
(a) the VV interval is within a tachycardia range defined as above the VF threshold but below a VT threshold and (b) the AA interval is either within normal limits or differs from the VV interval by more than a specified dual tachycardia limit value; and
,if a 1;
1 tachycardia condition is present, defined as when the AA and VV intervals are both within their tachycardia ranges and differ from one another by no more than a specified 1;
1 limit value, discriminate between a supraventricular tachycardia and a ventricular tachycardia based upon a relative variability of the VA and AV intervals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for operating a cardiac rhythm management device, comprising:
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detecting atrial senses corresponding to atrial depolarizations;
detecting ventricular senses corresponding to ventricular depolarizations;
computing an AA interval corresponding to a cycle length between consecutive atrial senses, a VV interval corresponding to a cycle length between consecutive ventricular senses, an AV interval corresponding to a cycle length between an atrial sense and a next occurring ventricular sense with no intervening atrial sense, and a VA interval corresponding to a cycle length between a ventricular sense and a next occurring atrial sense with no intervening ventricular sense;
computing variabilities for both the VA and AV intervals based upon their measured individual cycle lengths during a specified time window;
detecting a supraventricular tachycardia (SVT) when;
(a) the AA interval is within a tachycardia range defined as below an SVT threshold and (b) the VV interval is within normal limits;
detecting a ventricular fibrillation (VF) when the VV interval is below a VF threshold;
detecting a ventricular tachycardia (VT) when;
(a) the VV interval is within a tachycardia range defined as above the VF threshold but below a VT threshold and (b) the AA interval is either within normal limits or differs from the VV interval by more than a specified dual tachycardia limit value; and
,if a 1;
1 tachycardia condition is present, defined as when the AA and VV intervals are both within their tachycardia ranges and differ from one another by no more than a specified 1;
1 limit value, discriminating between a supraventricular tachycardia and a ventricular tachycardia based upon a relative variability of the VA and AV intervals. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A cardiac rhythm management device configured to detect atrial and ventricular beats and further configured to discriminate between a supraventricular tachycardia and a ventricular tachycardia by comparing a variability of an AV interval, defined as the interval between an atrial beat and a next occurring ventricular beat with no intervening atrial beat, with a variability of a VA interval, defined as the interval between a ventricular b eat and a next occurring atrial beat with no intervening ventricular beat.
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26. A method for discriminating between a supraventricular tachycardia and a ventricular tachycardia, comprising comparing a variability of an AV interval, defined as the interval between an atrial beat and a next occurring ventricular beat with no intervening atrial beat, with a variability of a VA interval, defined as the interval between a ventricular beat and a next occurring atrial beat with no intervening ventricular beat.
Specification