Dressler beats in ventricular tachycardia

Dressler beats in ventricular tachycardia

Dressler beat, named after William Dressler from Poland, is a fusion beat interrupting ventricular tachycardia (VT). Fusion beats are recognised by narrower QRS complexes than that of the tachycardia. It is the result of fusion of the ventricular tachycardia beat with a supraventricular beat which could be originating from the sinus node or any other supraventricular focus. Initial part of the QRS is contributed by conduction through the normal conduction system and preceded by a P wave, though it may not be obvious during a tachycardia. The presence of fusion beats (Dressler beats) along with capture beats, strongly support the diagnosis of VT in a wide QRS tachycardia.

The initial report by William Dressler and Hugo Roesler in 1952 had six instances of VT with fusion beats [1]. They noted that this occurs usually when the ventricular tachycardia rate is less than 150 beats per minute. When atrial activity is not visible to demonstrate atrioventricular dissociation during ventricular tachycardia, the presence of fusion beats helps in the diagnosis.

Dressler beats have been described in ventricular tachycardia occurring during atrial fibrillation as well [2].

Reference

1. William Dressler, Hugo Roesler. The occurrence in paroxysmal ventricular tachycardia of ventricular complexes transitional in shape to sinoauricular beats; a diagnostic aid. Am Heart J. 1952 Oct;44(4):485-93.
2. Young RL, Mower MM, Ramapuram GM, Tabatznik B. Atrial fibrillation with ventricular tachycardia showing “Dressler” beats. Chest. 1973 Jan;63(1):96-7.