Abstract

A 10-year-old female patient, previously healthy, had been experiencing recurrent episodes of palpitations for three months. An electrocardiogram performed in the emergency department during one of these episodes initially raised suspicion of supraventricular tachycardia (SVT) due to the abnormally elevated heart rate (HR) and a relatively narrow QRS complex (100 ms). Pharmacological cardioversion with adenosine was attempted but unsuccessful. Reversion to sinus rhythm occurred only after the administration of intravenous amiodarone at a dose of 5 mg/kg.

During subsequent outpatient evaluation with a specialist, the diagnosis of fascicular ventricular tachycardia (FVT) was established based on characteristic electrocardiographic findings (regular tachycardia with a QRS complex widened for age, right bundle branch block (RBBB) pattern associated with an anterosuperior fascicular block (ASFB), fusion beats, and atrioventricular dissociation). Pharmacological treatment with verapamil was initiated; however, due to symptom recurrence, the patient successfully underwent radiofrequency ablation and has remained asymptomatic and free of recurrence during clinical follow-up.