Classification of heartbeats based on intracardiac and body surface electrocardiogram (ECG) signals are provided. Intracardiac ECG (IC-ECG) signals and body surface ECG (BS-ECG) signals are processed to perform heartbeat classifications. A BS annotation of BS-ECG signals reflective of a sensed heartbeat is defined, the BS annotation including a BS annotation time value. IC annotations of IC-ECG signals which reflect atrial-activity or ventricular activity of the sensed heartbeat are also defined, each IC annotation including an IC annotation time value. The IC-ECG signals are discriminated as A-activity or V-activity and IC annotations are designated as IC-A annotations or IC-V annotations, respectively. A respective A/V time sequence comparison of IC annotations reflective of the sensed heartbeat is made with one or more time sequence templates for heartbeat classification. Morphology comparisons of the BS-ECG oscillating signal segments reflective of the sensed heartbeat morphology templates for classification may also be made. C)C co) C0' x E co rN i 0N( (D
Apparatus and method for heartbeat classification based on time sequence and morphology of introcardiac and body surface electrocardiogram (ECG) signals