PACEMAKER ARTIFACT SUPPRESSION IN CORONARY MONITORING

摘要

In heart monitoring systems for use with patients whose hearts may be stimulated by an artificial pacer and which system includes heart rate indicating means, there is provided circuitry for suppressing the recharge waveform portion of a pacer signal artifact in addition to suppression of the discharge pulse portion of the signal artifact, thereby to prevent inaccuracies in the heart rate indication arising from the pacer signal artifact. In addition to suppressing the discharge pulse portion of a pacer signal artifact with conventional means, the invention recognizes that the recharge waveform of the pacer signal may cause a false impression or a QRS complex which actuates heart rate indicating means and provides novel circuitry for suppressing such recharge waveform. Circuitry is provided for recognizing the occurrence of a pacer discharge pulse and for generating a suppression signal in timed relation thereto which, when arithmetically added to the recharge waveform portion, acts to cancel or suppress such recharge portion. The suppression signal is of inverse polarity to the recharge waveform portion and is generated by sampling the pacer signal artifact substantially at the beginning of the recharge waveform to determine the magnitude thereof. In a preferred embodiment, a pacer signal artifact and the termination of the discharge pulse portion thereof is identified by novel rate and duration measuring circuitry.