[Localization of the origin of idiopathic right ventricular tachycardia by body surface mapping]

To find the electrocardiographic indices for localizing the origin of idiopathic right ventricular tachycardia (VT), we investigated body surface maps and standard electrograms of 26 VTs of right ventricular outflow origin that were successfully abolished by radiofrequency catheter ablation. The origins were classified into three dimensional relationships; anterior (free wall) and posterior (septal), left (anterior attachment = AA) and right (posterolateral attachment = PA), and upper (near pulmonary valve = NP) and lower (far from pulmonary valve = FP) regions. The following indices on early to mid QRS isopotential maps were useful for localization; the location of minimum for differentiating free wall from septal origin, the potential distribution of upper left anterior chest for differentiating AA from PA region, and the time interval for which the minimum stays at upper anterior chest for differentiating NP from FP region. Electrocardiographic morphology in leads I, II and III, the amplitude of QS wave in leads aVR and aVL, and the amplitude of initial r wave in leads V1 and V2 were also reliable indices for localizing the origin of VT.