Pacemaker-Mediated Tachycardia: A Complication of Atrioventricular Universal (DDD) Pacemakers

The use of permanent implanted pacemakers as therapy for symptomatic bradyarrhythmias and conduction defects has shown steady growth, since the first implantation was reported in 1960. 1 The early permanent pacemakers were relatively simple devices that paced the ventricle at a fixed rate but did not sense intrinsic cardiac rhythm. During the past 24 years, pacemakers have become progressively more sophisticated devices. The advent of atrioventricular (AV) sequential pacing in the late 1960s and the noninvasive multiprogrammability and dual-chamber sensing and pacing (the so-called AV universal [DDD] pacemaker) in the mid-1970s has led to a tremendous rise in the use of more sophisticated devices. At Jefferson Medical College in Philadelphia dual-chamber devices accounted for 8% of all implantations in 1980. In 1982, 50% of pacemakers were dual-chamber devices, most of which were AV universal pacemakers. These figures are representative of nationwide statistics, 2 highlighting the increasing use of more versatile