Continuous ECGI mapping of spontaneous VT initiation, continuation, and termination with antitachycardia pacing

A 40-year-old woman with nonischemic cardiomyopathy and a left ventricular (LV) ejection fraction of 35% was referred for recurrent ventricular tachycardia (VT). She experienced 248 VT episodes treated by antitachycardia pacing (ATP) over 14 days. In 2005, she received an implantable cardioverter defibrillator for an episode of syncope and nonsustained VT. She later underwent an invasive electrophysiology study (EPS) with inducible VT and an ablation of the AV nodal reentrant tachycardia. Since then, she experienced symptomatic VT, terminated by ATP. Her VT was unresponsive to sotalol and mexiletine. Two EPS in early 2010 failed to induce VT despite intravenous isoproterenol and triple extrastimuli at two right ventricular (RV) sites; therefore, no ablations were performed.