1. A method for delivering therapy to a heart, comprising: providing a plurality of electrodes in or around the heart; delivering an electrical stimulus to the heart; measuring a polarization potential vector between at least a first pair of electrodes of the plurality of electrodes and a second pair of electrodes of the plurality of electrodes; comparing the polarization potential vector between at least the first pair of electrodes and the second pair of electrodes; and selecting a sensing pair of electrodes from at least the first pair of electrodes and the second pair of electrodes that yields the lowest polarization potential vector, the sensing pair of electrodes operable for use in sensing an evoked response of the heart to a subsequent electric stimulus delivered thereto.