A system and method to process segments of cardiac signals. Each of a plurality of segments in a first signal is correlated at a plurality of offsets to determine a highest correlation coefficient for each of the plurality of segments in the first signal. Each of a plurality of segments in a second signal is correlated at the plurality of offsets to determine a highest correlation coefficient for each of the plurality of segments in the second signal. A plurality of composite correlation coefficients is generated using highest correlation coefficients for segments of the first signal and segments of the second signal. The segments of the first and second signals are approximately contemporaneous. A set of segments including a segment from the first signal and a segment from the second signal is selected. The set is associated with a highest composite correlation coefficient from the plurality of composite correlation coefficients.