Abstract

Introduction: Adenosine ceases supraventricular arrhythmia affecting the atrioventricular (AV) node. It may also impact atrial tachycardias to discover the underlying mechanism.
Case report: A 51-year-old man was presented in the Emergency Department with supraventricular tachycardia and a heart rate 150 beats/min. Atrial flutter was identified as monomorphic atrial tachycardia with characteristic "saw-toothed heart" notched atrial waves. Adenosine 12 mg was administered, resulting in an atrioventricular block, unmasked the flutter waves, evolved to atrial fibrillation and rapid conversion to Normal Sinus Rhythm (NSR).
Conclusion: The administration of adenosine is an acceptable solution for an unknown SVT arrhythmia to reveal the underlying mechanism at least.

Key words: Adenosine, atrial flutter, tachycardia, cardioversion, ECG.