Epicardial Ablation in Post–Myocardial Infarction Ventricular Tachycardia

Since its first description by Sosa et al,1 catheter-based epicardial ablation has been increasingly used for catheter ablation of ventricular tachycardia (VT) due to a variety of substrates.2 It has been recognized that in idiopathic dilated cardiomyopathy, an epicardial origin is frequent and amenable to ablation in some cases.3,4 More recently, similar findings were described in arrhythmogenic right ventricular cardiomyopathy.5Article see p 882 However, the situation in VT related to chronic myocardial infarction (post-MI VT) seemed different. The surgical experience having a high success rate with subendocardial resection spoke for a subendocardial location of the VT substrate.6 The initial series of catheter-based VT ablation, involving well-tolerated VT ablated endocardially based on VT mapping during tachycardia, showed a relatively high acute success rate.7 However, VT recurrences were common.7 The introduction of the concept of substrate ablation, based on locating the VT substrate during sinus rhythm,8 has expanded catheter ablation to a larger number of VT patients, with reasonably good acute results, but the recurrence rate is still high.9,10 It has been suggested that this high recurrence rate could be related to a modification of the substrate over time because of the remodeling process,10 but this has never been demonstrated and the fight for an improvement in results continues.In this issue of the journal, Izquierdo et al11 searched in a different direction. What if the substrate, although partially endocardial, …