An automatic method for detecting heartbeats of a patient from two or more selected ECG signals, the method comprising: (a) determining a velocity for each of the selected signals； (b) summing together absolute values of each of the velocities； (c) comparing the sum with a threshold T having a value about one-half of an expected maximum value of the sum； and (d) if the sum is greater than the threshold T and if elapsed time since an immediately-previous heartbeat detection is greater than a preset refractory period tR, a heartbeat has been detected at a time tD of the velocity determinations. The method also further includes steps by which the detected heartbeats are categorized based on the velocities at the time of detection.
