A method and system of post-processing of sensing data generated by a medical device that includes transmitting a plurality of stored sensing data generated by the medical device to an access device, the stored sensing data including sensed atrial events and sensed ventricular events. The access device determines, in response to the transmitted data, instances where the medical device identified a cardiac event being detected in response to the sensing data, and determines, in response to the transmitted sensing data, whether one of the sensed ventricular events and the sensed atrial events is initiating conduction of a heart associated with the stored sensing data.