PACING OUTPUT COUPLING CAPACITOR FOR AUTOMATIC CAPTURE THRESHOLD DETECTION IN CARDIAC PACING SYSTEMS

摘要

This invention is a method, and apparatus for attenuating polarization voltages or "afterpotentials" which develop at the heart tissue/electrode interface following the delivery of a pacing stimulus to the heart tissue such that the evoked response of the heart may be accurately detected to determine whether each pacing stimulus resulted in heart capture or contraction, thereby facilitating improved tracking of the capture threshold, and minimizing power consumption while assuring therapeutic efficacy. The conventional large capacitance coupling capacitor (96) used to suppress DC components of the pacing spike has another, much lower capacitance capacitor (94) connected in series with it. The lower capacitance capacitor (94) may be operable in either the auto-threshold mode or in the normal pacing mode such that its value can be selectively inserted in series with the larger capacitance coupling capacitor (96) to effectively lower the overall capacitance of the coupling capacitor following delivery of the pacing stimulus.