Electrophysiology study (EPS) tracing of idiopathic left ventricular tachycardia

Idiopathic LV tachycardia originates from the inferior portion of the ventricular septum. Surface leads (I, II, III, V1, and V6), and intracardiac recordings from the high right atrium (HRA), His bundle region (HBE), right ventricular apex (RVA), right ventricular outflow tract (RVOT), and several recordings from the left ventricle at the site of successful ablation (LV fixed, LV var, LV bipol, LV uni) are shown. The presence of a sharp potential in the LV recordings (arrow) is consistent with local activation of the Purkinje system. This potential precedes the onset of the QRS during ventricular tachycardia (VT) by 40 msec.