Narrow Complex Tachycardia Is Not Always a Supraventricular Tachycardia: A Case of Ventricular Tachycardia Presenting as a Narrow Complex Tachycardia.

Ventricular tachycardia (VT) is a life-threatening arrhythmia in pediatric age. It is distinguished by a wide complex tachycardia on the electrocardiogram (ECG). Herein, we report the case of an 18-month-old toddler who presented with sudden-onset, narrow complex tachycardia at a heart rate of 240 bpm following an upper respiratory tract infection. Initial management, including multiple doses of adenosine and amiodarone, was unsuccessful. Synchronized cardioversion briefly restored sinus rhythm but was not sustained. Given the refractory nature of the tachycardia, an emergency electrophysiological (EP) study was performed, which revealed atrioventricular (AV) dissociation, confirming the diagnosis of VT despite the narrow QRS morphology. This case highlights the importance of considering VT in cases of refractory tachycardia, even when ECG findings suggest supraventricular tachycardia.