System and method for detecting evoked cardiac contractions
First Claim
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1. A method of detecting cardiac contractions induced in response to the application of pacing pulses to a patient heart having a predetermined minimum refractory period, comprising the steps of:
- applying a first pacing pulse to the patient'"'"'s heart;
detecting a first recovery artifact, indicative of cardiac activity, produced in response to application of said first pulse to the patient'"'"'s heart;
applying a second pacing pulse to the patient'"'"'s heart withina time period following the application of said first pulse which is less than said minimum refractory period of the patient'"'"'s heart;
detecting the recovery artifact, indicative of cardiac activity, produced in response to application of said second pulse to the patient'"'"'s heart; and
comparing said first and second recovery artifacts to determine whether cardiac contraction has occurred in response to the application of either of said first or second pacing pulses.
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Abstract
A system and method for detecting evoked cardiac contractions applies pacing pulses to a patient'"'"'s heart while simultaneously monitoring intracardiac electrical activity to detect evoked cardiac contractions. Pacing pulses are generated in pairs such that at most only one pulse of each pair can induce capture. The lead recovery waveforms produced in response to each of the pulses within a pair are electronically subtracted to yield a difference signal indicative of induced cardiac response.
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Citations
13 Claims
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1. A method of detecting cardiac contractions induced in response to the application of pacing pulses to a patient heart having a predetermined minimum refractory period, comprising the steps of:
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applying a first pacing pulse to the patient'"'"'s heart; detecting a first recovery artifact, indicative of cardiac activity, produced in response to application of said first pulse to the patient'"'"'s heart; applying a second pacing pulse to the patient'"'"'s heart withina time period following the application of said first pulse which is less than said minimum refractory period of the patient'"'"'s heart; detecting the recovery artifact, indicative of cardiac activity, produced in response to application of said second pulse to the patient'"'"'s heart; and comparing said first and second recovery artifacts to determine whether cardiac contraction has occurred in response to the application of either of said first or second pacing pulses. - View Dependent Claims (2)
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3. A system for detecting the responsiveness of a patient heart having a predetermined minimum refractory period to pacing pulses having a predetermined energy level, comprising:
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generating means electrically coupled to the heart for generating a series of pacing events signals, each comprising a pair of pulses each of said predetermined energy level separated in time by less than the refractory perod of the heart; detection means electrically coupled to the heart for detecting the artifact signal produced by the heart in response to each of said paired pulses; and comaprison means for comparing the artifact signal detected in response to the first pulse with the artifact signal detected in response to the second pulse of each pacing event signal to determine whether capture has occurred at the energy level of the pulses comprising that signal. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10)
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11. A system for detecting the responsiveness of a patient heart having a predetermined minimum refractory period to pacing pulses having a predetermined energy level, comprising:
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generating means electrically coupled to the heart for generating a series of pacing event signals, each comprising a pair of pulses each of said predetermined energy level separated in time by less than the refractory period of the heart; detection means electrically coupled to the heart for detecting the artifact signal produced by the heart in response to each of said paired pulses; and first waveform storage means for storing the first artifact signal occurring during each pacing signal; second waveform storage means for storing the second artifact signal occurring during each pacing signal; subtraction means for subtracting following each pacing event the absolute values of the artifact signals stored in said first and second storage means to develop a different signal; integrating means for integrating said difference signal to develop an integrated different signal; and output circuit means for providing an output signal indicative of capture when said integrated difference signal exceeds a predetermined threshold level. - View Dependent Claims (12, 13)
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Specification