Method and system for automatically classifying intracardiac electrograms
First Claim
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1. A method for automatically classifying intracardiac electrograms, comprising the steps of:
- (a) receiving a first input signal representing an electrogram;
(b) extracting timing parameters from the first input signal, and deriving from them a first output signal;
(c) receiving a second input signal representing the electrogram;
(d) training a neural network using a signal representative of an arrhythmia to recognize that arrhythmia;
(e) deriving a second output signal, which is a measure of the electrogram'"'"'s likeness to the signal representative of the arrhythmia, from the second input signal, using the neural network; and
(f) indicating the classification taking into account the first output signal derived in step (a), and the second output signal derived in step (b).
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Abstract
The application is directed to a method for automatically classifying intracardiac electrograms, and a system for performing the method. In a further aspect, it concerns an implantable cardioverter defibrillator which incorporates the system and uses the method to monitor cardiac activity and deliver appropriate treatment. The method uses a combination of timing analysis and pattern matching using a neural network in order to correctly classify the electrograms. This technique allows both changes in rate and morphology to be taken into account.
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19 Claims
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1. A method for automatically classifying intracardiac electrograms, comprising the steps of:
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(a) receiving a first input signal representing an electrogram; (b) extracting timing parameters from the first input signal, and deriving from them a first output signal; (c) receiving a second input signal representing the electrogram; (d) training a neural network using a signal representative of an arrhythmia to recognize that arrhythmia; (e) deriving a second output signal, which is a measure of the electrogram'"'"'s likeness to the signal representative of the arrhythmia, from the second input signal, using the neural network; and (f) indicating the classification taking into account the first output signal derived in step (a), and the second output signal derived in step (b). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A system for automatically classifying intracardiac electrograms comprising:
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first signal receiving means to receive a first input signal representing an electrogram;
timing classification means to derive a first output signal from timing parameters extracted from the first input signal;second signal receiving means to receive a second input signal representing the electrogram;
a neural network trained using a signal representative of an arrhythmia to recognize that arrhythmia and including means to derive a second output signal which is a measure of the second input signal'"'"'s likeness to the signal representative of the arrhythmia; anddecision means operative, taking into account the first output signal from the timing classification means and the second output signal from the neural network, to indicate the classification. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. An implantable cardioverter defibrillator comprising:
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first signal receiving means to receive a first input signal representing an electrogram;
timing classification means to derive a first output signal from timing parameters extracted from the first input signal;second signal receiving means to receive a second input signal representing the electrogram;
a neural network trained using a signal representative of an arrhythmia to recognize that arrhythmia and including means to derive a second output signal which is a measure of the second input signal'"'"'s likeness to the signal representative of the arrhythmia; anddecision means operative, taking into account the first output signal from the timing classification means and the second output signal from the neural network, to indicate the classification; wherein the first and second signal receiving means consist of sensing electrodes; and
which includes means to use the indicated classification to determine the appropriate therapy to apply.
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19. A method for automatically classifying intracardiac electrograms, comprising the steps of:
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receiving a first input signal having two channels and representing ventricular activity in a first channel and atrial activity in the second channel; extracting timing parameters from a first input signal, wherein the timing parameters extracted are the ventricular channel period, the atrial channel period, and the phase difference between the ventricular and atrial channels deriving from the timing parameters a first output signal; determining whether the ventricular period is less than a first threshold and indicating, in the first output signal, ventricular fibrillation if the ventricular period is lesser than the first threshold; determining whether the ventricular period is between the first threshold and a second, higher, threshold and determining whether the ratio of the period of the atrial waveform to the period of the ventricular waveform is greater than a predetermined amount; and
indicating, in the first output signal, ventricular fibrillation if the ventricular period is between the first and second threshold and the ratio is greater than the predetermined amount;determining whether the ventricular period is greater than the second threshold and determining whether the ratio of the period of the atrial waveform to the period of the ventricular waveform is greater than a predetermined amount; and
indicating, in the first output signal, ventricular tachycardia if the ventricular period is greater than the second threshold and the ratio is greater than the predetermined amount;
otherwise,determining whether the atrial period is less than a third threshold, between the first and second; and
indicating, in the first output signal, supraventricular tachycardia if the atrial period is less than the third threshold;determining whether the ratio of the phase difference between the ventricular channel and the atrial channel, and the ventricular period is less than a predetermined amount; and
indicating, in the first output signal, normal sinus rhythm if the ratio is less than the predetermined amount;otherwise indicating, in the first output signal, supraventricular tachycardia.
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Specification