Accelerated idioventricular rhythm

Sinus rhythm interrupted by an accelerated idioventricular rhythm (AIVR). The first beat (N) is a normally conducted sinus beat; the very wide beats are ventricular beats (V); and the beats marked F are fusion beats due to "collision" of a sinus beat and a ventricular beat. Note how the P waves become dissociated from the QRS complexes during the idioventricular rhythm. AIVR is usually seen with underlying heart disease and represents a "slow" type of ventricular tachycardia that does not generally warrant specific therapy. AIVR may be a marker of reperfusion during acute myocardial infarction, occurring spontaneously or after reperfusion therapy. The slow ventricular rate distinguishes this arrhythmia from nonsustained ventricular tachycardia in which the ventricular rate is above 100 beats/min.