Accelerated idioventricular rhythm differential diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

AIVR must be distinguished from normal sinus rhythm, junctional tachycardia, and slow VT.

Because of its slower rate, AIVR may resemble normal sinus rhythm (NSR). AIVR is disnguished by the presence of numerous fusion beats to distinguish it from NSR. Given the difficulty in distinguishing these rhythms, the term accelerated isorhythmic ventricular rhythm has been suggested.

AIVR should also be distinguished from junctional tachycardia with preexisting intraventricular conduction delays (IVCD)s. In patients with junctional tachycardia, there are no fusion beats or capture beats.

In general, the rate of AIVR is slower (<100-120 bpm) than ventricular tachycardia (at least 100-120 bpm). There can, however, be overlap in the rate associated with AIVR and slow VT. The distinction is critical as misdiagnosis as slow VT can results in inappropriate therapy such as cardioversion and anti-arrhythmic administration.

Template:WH Template:WS