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Cardiac pacemakers are implanted in patients who suffer from bradycardic dysrhythmias. If the patient’s intrinsic rhythm falls below a set target, the pacemaker will provide an electrical stimulus to the myocardium.

Pacemakers are designated with a five‐letter code; the first three letters are referred to most often. The first letter indicates the chamber paced, the second letter indicates the chamber sensed, and the third letter the response after sensing (Box 11.3) [24, 25]. Pacemakers can be single chamber or dual chamber. The more common single‐chamber pacemaker is VVI, which paces the ventricle, senses the ventricle, and inhibits the output pulse if intrinsic ventricular activity is detected. The more common dual‐chamber pacemaker is DDD, which paces and senses in both the atrium and ventricle and has dual response to sensed intrinsic activity [25].