Patent ID: 7092756

Claim:
A cardiac pacing system for use with unipolar or bipolar atrial and ventricular pacing and sensing leads, said cardiac pacing system including: (a) at least an atrial lead having atrial electrodes comprising an atrial tip electrode and an atrial ring electrode electrically coupled thereto; (b) at least a ventricular lead having ventricular electrodes comprising a ventricle tip electrode and a ventricle ring electrode electrically coupled thereto; (c) pacing means for providing a pacing stimulus to at least one of an atrium or ventricle of a heart, said pacing means electrically coupled to at least one of said atrial lead and said ventricular lead; (d) sensing means for sensing a response evoked by the pacing stimulus, said sensing means electrically coupled to at least one of said atrial lead and said ventricular lead said sensing means including multiple independent blanking switches corresponding to independent electrodes; (e) an indifferent electrode and an electrically conductive can that contains the pacing and sensing means, said indifferent electrode being positioned on the can; (f) afterpotential attenuation means for attenuating afterpotentials which result due to the application of the pacing stimulus to the heart by said cardiac pacing system, said afterpotential attenuation means being electrically coupled to said pacing means and including first coupling capacitor means for attenuating afterpotential operatively coupled to second coupling capacitor means for blocking DC components, and also including switching means for selectively coupling said second coupling capacitor means in series with said first coupling capacitor means so as to reduce the effective capacitance of said second coupling capacitor means, said system having a combined reduced coupling capacitance of less than 5 microfarads; and (g) wherein the sensing means is adapted to selectively sense evoked responses between all combinations of any two of said electrodes.