We performed an electrophysiological study, using non-contact mapping, in an 8-year-old girl weighing 39.9 kg who had suffered recurrent symptomatic episodes of exercise-induced non-sustained ventricular tachycardia. Color-coded isopotential maps of the ventricular tachycardia identified the area of earliest endocardial activation high and anterior in the right ventricular outflow tract. Although partial deflation of the balloon was required to position the ablation catheter at the earliest site of activation, this site was still identified accurately, as demonstrated by termination of the ventricular tachycardia and ectopy upon mechanical pressure, as well as application of radiofrequency current.

In this young patient, precise mapping of the earliest endocardial activation using the non-contact mapping system was safe and effective, allowing successful radiofrequency ablation of the tachycardia.