PACING OUTPUT CIRCUITRY FOR AUTOMATIC CAPTURE THRESHOLD DETECTION IN CARDIAC PACING SYSTEMS

摘要

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 for minimizing power consumption while assuring therapeutic efficacy. The conventional large capacitance coupling capacitor used to suppress DC components of the pacing spike has a second, much lower capacitance capacitor connector in series with it, the second capacitor being shunted by a switch so that its value can be selectively inserted in series with the coupling capacitor to effectively lower the overall capacitance of the coupling capacitor following delivery of the pacing spike.