Non-sustained broad-complex tachycardia following intravenous adenosine.

Adenosine induces short-lived atrioventricular nodal (AVN) blockade when injected intravenously and has superceded verapamil as the drug of choice for the termination of re-entrant paroxysmal supraventricular tachycardias (PSVT).' It has also been found to be useful in the diagnosis of broad-complex tachycardia, distinguishing PSVT with aberrant conduction, which is terminated by adenosine, from pre- excited atrial arrhythmias and ventricular tachycardia (VT), which are not.This agent's excellent safety profile is, in part, a reflection of its short half-life and the more frequent side-effects of dyspnoea, flushing and chest pain are transient and well tolerated. Al- though rhythm disturbances (predominantly bradyarrhythmias) have been described, few serious arrhythmia complications have been documented. We report the observation of non-sustained broadcomplex tachycardia following intravenous adenosine for the treatment of PSVT.