Cardiac arrhythmia analysis system
First Claim
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1. A system for identifying a QRS complex in an electro-cardiac signal representative of cardiac electrical activity, comprising:
- (a) differentiator means, responsive to said electro-cardiac signal, for producing the derivative thereof;
(b) rectifying and filtering means, responsive to said electro-cardiac signal, for producing a signal representative of the low-pass filtered absolute value of said electro-cardiac signal;
(c) first comparator means, responsive to the derivative of said electro-cardiac signal and to said low-pass filtered absolute value signal, for producing a resultant signal when the total of a predetermined reference level less the sum of said derivative and said low-pass filtered absolute value signal is greater than zero; and
(d) output means, responsive to said resultant signal and to said low-pass filtered absolute value signal, for producing an output signal representative of the occurrence of a QRS complex upon the occurrence of said resultant signal when the amplitude of said low-pass filtered absolute value signal exceeds a predetermined threshold level.
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Abstract
A method and apparatus for analyzing cardiac electrical activity and producing a signal representative of the occurrence of a QRS complex. A signal representative of cardiac electrical activity is analyzed by an analog circuit that compares the sum of the rectified and low-pass filtered signal plus the derivative of the signal to a reference level, and compares the rectified and filtered signal to a threshold level, to identify QRS complexes while largely ignoring ventricular fibrillation, and produces an output pulse representative of the occurrence of a QRS complex.
18 Citations
6 Claims
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1. A system for identifying a QRS complex in an electro-cardiac signal representative of cardiac electrical activity, comprising:
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(a) differentiator means, responsive to said electro-cardiac signal, for producing the derivative thereof; (b) rectifying and filtering means, responsive to said electro-cardiac signal, for producing a signal representative of the low-pass filtered absolute value of said electro-cardiac signal; (c) first comparator means, responsive to the derivative of said electro-cardiac signal and to said low-pass filtered absolute value signal, for producing a resultant signal when the total of a predetermined reference level less the sum of said derivative and said low-pass filtered absolute value signal is greater than zero; and (d) output means, responsive to said resultant signal and to said low-pass filtered absolute value signal, for producing an output signal representative of the occurrence of a QRS complex upon the occurrence of said resultant signal when the amplitude of said low-pass filtered absolute value signal exceeds a predetermined threshold level. - View Dependent Claims (2, 3, 4, 5)
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6. A method for analyzing an electro-cardiac signal to detect the occurrence of a QRS complex, comprising:
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(a) differentiating the electro-cardiac signal; (b) rectifying and filtering the electro-cardiac signal; (c) adding the derivative of the electro-cardiac signal to the rectified and filtered electro-cardiac signal to produce a sum signal; (d) comparing said sum signal to a reference level; and (e) comparing said rectified and filtered electro-cardiac signal to a predetermined threshold level, the occurrence of a QRS complex being indicated by the simultaneous occurrence of the sum of the derivative of said electro-cardiac signal and the rectified and filtered electro-cardiac signal being less than said reference level and said rectified and filtered electro-cardiac signal exceeding said threshold level.
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Specification