Abstract
Non-reentrant fascicular tachycardia (NRFT) developed in a 6-year-old Japanese boy. Because of drug-resistant recurrences, he received catheter mapping and ablation at age 10 years. An electrocardiogram exhibited a superior left-axis deviation, a right bundle branch block-type configuration, and relatively narrow QRS with sharp R wave. It suggested verapamil-sensitive ventricular tachycardia (VT), but showed no sensitivity to verapamil or reentrant characteristics in the electrophysiological study. Detailed VT mapping determined the earliest presystolic Purkinje potential on the left posterior fascicle at the mid-ventricular septum. Radiofrequency current applications to the lesion led to his NRFT-free life without restriction. LEARNING OBJECTIVES: Purkinje-related idiopathic ventricular tachycardias (VTs) are commonly due to reentrant mechanisms, and non-reentrant fascicular tachycardia (NRFT) is a rare form of idiopathic VT in adults. Although it is crucial to distinguish NRFT from reentrant VTs, there is no information about the electrophysiological studies and the treatment effect in pediatric-onset NRFT.