Patent ID: 7697977

Claim:
A cardiac rhythm management device, comprising: a plurality of electrodes for disposition near selected myocardial sites; a plurality of sense amplifiers for amplifying electrogram signals received from selected pairs of the plurality of electrodes; at least one pulse generator for outputting pacing pulses to a selected pair of the plurality of electrodes; a controller for controlling the output of pacing pulses and interpreting electrogram signals; a switching network operated by the controller for connecting a selected electrode pair to a selected sense amplifier or to a selected pulse generator; wherein the controller is programmed with executable instructions for performing functions which include determining relative depolarization times during a cardiac contraction at two selected myocardial sites by: connecting a first electrode of said plurality of electrodes disposable at a first myocardial site to one differential input of a sensing amplifier of said plurality of sense amplifiers and connecting a second electrode of said plurality of electrodes disposable at a second myocardial site to the other differential input of said sensing amplifier; sensing a biphasic electrogram generated by the first and second electrodes during a cardiac contraction, where the biphasic electrogram has positive and negative peaks corresponding to the cardiac contraction's depolarization at the first and second myocardial sites; and, determining which of the first and second myocardial sites is depolarized first during the cardiac contraction by determining that the first myocardial site is depolarized before the second myocardial site if a positive peak occurs before a negative peak in the biphasic electrogram or that the second myocardial site is depolarized before the first myocardial site if a negative peak occurs before a positive peak in the biphasic electrogram.