System and method for waveform morphology comparison
First Claim
1. A method for comparing a test electrogram to a template electrogram, comprising the steps of:
- (a) collecting a template electrogram;
(b) collecting a test electrogram;
(c) locating a group of three consecutive peaks having a largest cumulative peak amplitude in said template electrogram and extracting template peak information from that portion of said template electrogram;
(d) locating a group of three consecutive peaks having a largest cumulative peak amplitude in said test electrogram and extracting test peak information from that portion of said test electrogram;
(e) comparing polarities and positions of said test peak information with polarities and positions of said template peak information to align said test electrogram with said template electrogram; and
(f) comparing said test peak information with said template peak information to generate a score indicative of similarity between said template electrogram and said test electrogram to thereby provide an indication of whether said test and template electrograms originate from a same region of a patient'"'"'s heart.
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Abstract
A ventricular tachycardia (VT) complex is distinguished from a sinus tachycardia or a supraventricular tachycardia. A template based on morphology of a normal sinus rhythm is collected. A test signal is compared against the template to determine how closely the test and template signals correspond based on morphology. The comparison is done based on peak information in the template and the test signal. A score is generated to indicate the degree of similarity between the template and the test signal. The peak information is extracted as follows. First, a group of three consecutive peaks having a largest cumulative peak amplitude is located in the template and in the test signal. The polarity, position and area of each peak within the group is then determined. The area of each peak is normalized. The polarities, positions and normalized areas represent the peak information that is used for comparison.
307 Citations
21 Claims
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1. A method for comparing a test electrogram to a template electrogram, comprising the steps of:
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(a) collecting a template electrogram; (b) collecting a test electrogram; (c) locating a group of three consecutive peaks having a largest cumulative peak amplitude in said template electrogram and extracting template peak information from that portion of said template electrogram; (d) locating a group of three consecutive peaks having a largest cumulative peak amplitude in said test electrogram and extracting test peak information from that portion of said test electrogram; (e) comparing polarities and positions of said test peak information with polarities and positions of said template peak information to align said test electrogram with said template electrogram; and (f) comparing said test peak information with said template peak information to generate a score indicative of similarity between said template electrogram and said test electrogram to thereby provide an indication of whether said test and template electrograms originate from a same region of a patient'"'"'s heart. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for comparing a test electrogram to a template electrogram, comprising the steps of:
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(a) collecting a template electrogram; (b) collecting a test electrogram; (c) extracting template peak information from said template electrogram; (d) extracting test peak information from said test electrogram; (e) comparing polarities and positions of said test peak information with polarities and positions of said template peak information to align said test electrogram with said template electrogram; (f) comparing said test peak information with said template peak information to generate a score indicative of similarity between said template electrogram and said test electrogram; (g) if in step (e) peaks in said template electrogram and said test electrogram do not match in position and polarity, then in step (f) calculating said score as the sum of the magnitudes of the areas of unmatched template peaks, the areas of unmatched test peaks, and the difference between the areas of any matched template and test peaks; and (h) if in step (e) peaks in said template electrogram and said test electrogram all match in position and polarity, then in step (f) calculating said score as the sum of the magnitudes of the differences between the areas of the matched peaks.
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14. An apparatus for comparing a test electrogram to a template electrogram, comprising:
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(a) collection means for collecting and storing a template electrogram and a test electrogram; (b) peak extraction means for extracting template peak information from said template electrogram and for extracting test peak information from said test electrogram) said extraction means comprising means for locating a group of three consecutive peaks having a largest cumulative area in said electrogram, means for determining a polarity of each peak within said group, means for determining a position of each peak within said group, and means for normalizing the area of each peak in said group, wherein said polarities, said positions and said normalized areas represent said extracted peak information; (c) comparison means for comparing polarities and positions of said test peak information with polarities and positions of said template peak information to align said test electrogram with said template electrogram; and (d) score means for comparing said test peak information with said template peak information to generate a score indicative of similarity between said template electrogram and said test electrogram to thereby provide an indication of whether said test and template electrograms originate from a same region of a patient'"'"'s heart. - View Dependent Claims (15, 16, 17)
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18. A method for distinguishing between a ventricular tachycardia complex and a sinus tachycardia or supra ventricular tachycardia complex, comprising the steps of:
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(a) collecting a template intraventricular electrogram and a test intraventricular electrogram; (b) for each of said intraventricular electrograms, (1) locating a group of three consecutive peaks having a largest cumulative area, (2) determining a polarity and a position of each peak within said group, and (3) normalizing the area of each peak in said group, wherein said polarities, said positions and said normalized areas represent extracted peak information; (c) comparing polarities and positions of said extracted peak information for said test intraventricular electrogram with polarities and positions of said extracted information for said template intraventricular electrogram to align said test intraventricular electrogram with said template intraventricular electrogram; and (d) comparing said extracted peak information for said test intraventricular electrogram with said extracted information for said template intraventricular electrogram to generate a score indicative of similarity between said template intraventricular electrogram and said test intraventricular electrogram. - View Dependent Claims (19, 20, 21)
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Specification