Abstract: Apparatus is provided including an implantable sensor, adapted to sense an electrical parameter of a heart of a subject, and a first control unit, adapted to apply pulses to the heart responsively to the sensed parameter, the pulses selected from the list consisting of: pacing pulses and anti-arrhythmic energy. The apparatus further includes an electrode device, adapted to be coupled to a site of the subject selected from the list consisting of: a vagus nerve of the subject, an epicardial fat pad of the subject, a pulmonary vein of the subject, a carotid artery of the subject, a carotid sinus of the subject, a coronary sinus of the subject, a vena cava vein of the subject, a right ventricle of the subject, and a jugular vein of the subject; and a second control unit, adapted to drive the electrode device to apply to the site a current that increases parasympathetic tone of the subject and affects a heart rate of the subject. The first and second control units are not under common control.

Abstract: Apparatus is provided including an electrode device, adapted to be coupled to a site of a subject; and a control unit, adapted to drive the electrode device to apply a current to the site intermittently during alternating “on” and “off”periods, each of the “on” periods having an “on” duration equal to between 1 and 10 seconds, and each of the “off” periods having an “off”duration equal to at least 50% of the “on” duration. Other embodiments are also described.