Electronic pacemakers.

The number of patients who have cardiac pacemakers has increased markedly over the past few decades since the technology was first introduced in the 1950s. Advances in technology, expanding indications, and the aging of the population ensure that clinicians will encounter patients with cardiac pacemakers on a regular basis. This article summarizes the electrocardiographic manifestations of the normally functioning permanent cardiac pacemaker and abnormalities associated with pacemaker malfunction.