Accelerated idioventricular rhythm detected during elective surgery in a healthy man

Accelerated idioventricular rhythm (AIVR) is found most commonly in the presence of underlying heart disease. It is characterized by acceleration of a latent pacemaker that normally depolarizes slowly. We describe a 30-year-old man who was found to have episodes of accelerated idioventricular rhythm (AIVR) on cardiac monitoring during elective orthopedic surgery. Noninvasive evaluation including two-dimensional echocardiography was unremarkable. No late potentials were detected on a signal-averaged electrocardiogram. During an exercise tolerance test, AIVR was suppressed as heart rate increased. A 24-h Holter monitor revealed that the AIVR rate was consistently 73-76 beats/min, which appeared whenever the sinus rate slowed to this level. The patient has been asymptomatic, and the rhythm has persisted at least through a 5-month follow-up period.