A system and method for discriminating cardiac rhythms in sensed cardiac
complexes associated with at least two cardiac signals, which includes at
least two electrodes disposed at different locations in a heart for
sensing at least two cardiac signals. A controller through a sensing
circuit receives the sensed at least two cardiac signals from the
electrodes and processes the sensed at least two cardiac signals to
compute interelectrode time differences between the cardiac complexes
associated with one of the at least two sensed cardiac signals, and
corresponding cardiac complexes associated with the other of the at least
two sensed cardiac signals. The controller further computes a detection
time difference variability from the computed interelectrode detection
time difference variabilities. Then the controller compares the computed
detection time difference variability to a predetermined detection time
difference variability threshold value to discriminate whether the sensed
at least two cardiac signals have a coordinated or an uncoordinated
cardiac rhythm.