A system for heart performance characterization and abnormality detection includes an interface for receiving sampled data representing an electrical signal indicating electrical activity of a patient heart over multiple heart beat cycles and for receiving a pace signal indicating occurrence of a heart pace pulse applied to the heart. A signal processor uses the received sampled data and pace signal in calculating, a first signal characteristic value comprising a time interval between occurrence of the pace pulse and a cardiac cycle characteristic and a second signal characteristic comprising an average of the time intervals determined over a multiple heart cycles. A comparator compares at least one of the first and second characteristic values with a threshold value to provide a comparison indicator. A patient monitor generates an alert message associated with the threshold in response to the comparison indicator indicating a calculated signal characteristic value exceeds the threshold value.
