Recent Developments in Cardiac Pacemakers: Rate-Responsive Pacing

In brief: Over the last 30 years cardiac pacemakers have evolved from simple devices only capable of fixed-rate stimulation of a single chamber of the heart to more sophisticated units able to sense and stimulate electrical activity in both the atrium and the ventricle. These refinements have allowed for more physiologic pacing with maintenance of atrioventricular synchrony and cardiac output. Most recently, new technology has led to development of a single-chamber pacemaker that senses skeletal muscle activity and increases the heart rate in response to exercise. By increasing cardiac output with activity, this rate-responsive pacemaker allows greater exercise tolerance.