Unveiling a Rare Side Effect: A Report of a Unique Case of Second-Degree Type 2 Sinoatrial Node Exit Block Induced by Adenosine Infusion.

Adenosine is a widely used pharmacologic agent in the field of cardiology, predominantly for the termination of supraventricular tachycardias and diagnostic purposes. Most of the side effects are short-lasting due to its very short half-life. Fatal complications of adenosine are rare but can include ventricular fibrillation, ventricular tachycardia, and asystole. Proper medical supervision and monitoring are crucial to minimize risks. We report a unique case of a second-degree type 2 sinoatrial node exit block following intravenous adenosine administration in a 25-year-old male presenting with palpitations.

Dual atrio ventricular node in heterotaxy syndrome.

Our interesting electrocardiogram has two qRS morphology without features of preexcitation suggesting two atrio ventricular node conduction system. All cardiologists should be aware of this feature in heterotaxy syndrome as reentrant supraventricular tachycardia may develop in these patients.