Accelerated idioventricular rhythm definition

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

An Accelerated Idioventricular Rhythm is defined as an ectopic ventricular rhythm at a rate between 40 bpm and 100 to 120 bpm. This rate is faster than the intrinsic rhythm (40 bpm) but slower than that of ventricular tachycardia (which would be > 100 to 120 bpm). The ventricular origin of this rhythm can be demonstrated by the usual EKG criteria which include AV dissociation, fusion beats, and capture complexes.

The rate of cardiac contraction is determined by the intrinsic rate of depolarisation of the cardiac cells. In normal hearts the sinoatrial node in the atria depolarises at a rate of 70 beats per minute. This suppresses the intrinsic depolarisation of the other parts of the heart.

The accelerated idioventricular rhythm occurs when depolarisation rate of a normally suppressed focus increases to above that of the “higher order” focuses (the sinoatrial node and the atrioventricular node). This most commonly occurs in the setting of a sinus bradycardia.

CME Category::Cardiology