A wristband having inner and outer sensing electrodes capable of acquiring signals from bipolar limb leads and being electrically associated with electronics capable of processing such signals in a form representative of the electrical activity of the heart. The inner electrode is in continual electrical contact with the skin of the wrist upon which the band is worn. The outer electrode is isolated from the inner electrode and includes an outer portion exposed for contact by the fingers of the wearer's opposite hand. When such finger contact with the outer electrode is made, the bipolar circuit is completed and the ECG skin potential signals are sensed at the electrodes. The signals are processed to produce a digital indication of heartbeat rate, or other signal representative of heart activity.