Idioventricular Rhythm

Excerpt

Idioventricular rhythm is a slow regular ventricular rhythm, typically with a rate of less than 50, absence of P waves, and a prolonged QRS interval. When the sinoatrial node is blocked or suppressed, latent pacemakers become active to conduct rhythm secondary to enhanced activity and generate escape beats that can be atrial itself, junctional or ventricular. When ventricular rhythm takes over, it is essentially called Idioventricular rhythm.

Idioventricular rhythm is similar to ventricular tachycardia, except the rate is less than 60 bpm and is alternatively called a 'slow ventricular tachycardia.' When the rate is between 50 to 110 bpm, it is referred to as accelerated idioventricular rhythm.

Accelerated idioventricular rhythm (AIVR) results when the rate of an ectopic ventricular pacemaker exceeds that of the sinus node with a rate of around 50 to 110 bpm and often associated with increased vagal tone and decreased sympathetic tone. It is a hemodynamically stable rhythm and can occur after a myocardial infarction during the reperfusion phase.