INTRODUCTION
Catheter ablation is an effective therapy for ventricular tachycardia (VT) in patients with structural heart disease. Endocardial ablation was often supplemented by epicardial ablation in 15-30% of patients to achieve success.(1-3) Percutaneous epicardial mapping and ablation was first attempted by Sosa and his colleagues.(4) Since then, this technique has been widely used in patients with non-ischemic cardiomyopathy (NICM), arrhythmogenic right ventricular cardiomyopathy (ARVC) and some focal VTs originating epicardially.(5-7) Unfortunately, some VTs are still refractory to combined endocardial and epicardial ablation. These challenging VTs often progress to electrical storm causing frequent implantable cardioverter defibrillator (ICD) shocks and significantly increase the mortality. (8-9) The intramural or subepicardial VT substrate may cause the ablation failure. Percutaneous epicardial ablation frequently was limited by poor contact force or fat tissue. Some non-conventional ablation strategies for intramural ventricular arrhythmias have been reported recently including bipolar ablation, needle ablation, half-normal saline irrigated ablation. (10-12) However, these techniques required specific devices or equipment which have not been available in most of centers. Transvessel ethanol ablation has also been reported as an effective alternative strategy for VTs with previously failed radiofrequency ablation.(13, 14) However, its success was limited by the anatomy of coronary branches. Surgical epicardial ablation has been reported as a feasible alternative strategy for VTs.(15-17) Meanwhile, intramyocardial ethanol injection has been proved effectively in animal models. (18) There have been no reports on effects of intramyocardial ethanol injection for the treatment of VTs in human. We hypothesized that surgical catheter ablation supplemented by direct ethanol injection might be a powerful treatment in those challenging VTs, especially when concomitant surgical interventions were needed.