Successful mapping and ablation of a pediatric-onset non-reentrant fascicular tachycardia

Non-reentrant fascicular tachycardia (NRFT) developed in a 6-year-old Japanese boy. Because of the 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 for 16 months.