Multiple stage morphology-based system detecting ventricular tachycardia and supraventricular tachycardia
First Claim
1. A method comprising:
- sensing cardiac signals representative of electrical cardiac activity;
during a tachycardia event, detecting a sensed R-wave from one or more complexes of the cardiac signals;
measuring a width of the sensed R-wave;
comparing the width of the sensed R-wave to a template R-wave width;
if the width of the sensed R-wave is less than a predetermined value of the template R-wave width, analyzing a morphological similarity of the cardiac signals to a normal sinus rhythm template complex to determine if a ventricular tachycardia condition is present.
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Abstract
A system for detecting ventricular tachycardia and supraventricular tachycardia using a multiple stage morphology based system. Cardiac signals are sensed from a patient'"'"'s heart and analyzed for the occurrence of a tachycardia event. When a tachycardia event is detected, the method and system analyzes a plurality of features of the sensed cardiac signals in two or more discrimination stages. Each of the two or more discrimination stages classify the tachycardia event as either a ventricular tachycardia or a candidate supraventricular tachycardia event. When a discrimination stage detects the occurrence of a ventricular tachycardia, therapy is delivered to the heart to treat the ventricular tachycardia.
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Citations
11 Claims
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1. A method comprising:
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sensing cardiac signals representative of electrical cardiac activity;
during a tachycardia event, detecting a sensed R-wave from one or more complexes of the cardiac signals;
measuring a width of the sensed R-wave;
comparing the width of the sensed R-wave to a template R-wave width;
if the width of the sensed R-wave is less than a predetermined value of the template R-wave width, analyzing a morphological similarity of the cardiac signals to a normal sinus rhythm template complex to determine if a ventricular tachycardia condition is present. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
declaring a ventricular tachycardia when the number of ventricular tachycardia complexes reaches a predetermined threshold; and
delivering therapy for treating the ventricular tachycardia when a ventricular tachycardia is declared.
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9. The method of claim 1, where the act of analyzing a morphological similarity includes the acts of:
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analyzing a plurality of features of the sensed cardiac signals;
determining values for each of the plurality of features of the sensed cardiac signals;
determining a similarity value and a dissimilarity value for each of the cardiac signals using the values for each of the plurality of features of the sensed cardiac signals, where the similarity value and the dissimilarity value are assessed relative the normal sinus rhythm template complex; and
using the similarity value and the dissimilarity value to determine if each of the cardiac signals is a ventricular tachycardia complex.
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10. The method of claim 9, wherein the step of using the similarity value and the dissimilarity value includes the acts of:
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defining a boundary on a discrimination plane, where the boundary separates a ventricular tachycardia region from a non-ventricular tachycardia region;
classifying cardiac signals falling in the ventricular tachycardiac region as tachycardia complexes; and
classifying cardiac signals falling in the non-ventricular tachycardiac region as supraventricular tachycardia complexes.
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11. The method of claim 9, including the acts of:
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declaring a ventricular tachycardia when the number of ventricular tachycardia signals reaches a predetermined threshold; and
delivering therapy for treating the ventricular tachycardia when a ventricular tachycardia is declared .
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Specification