SY07-4 Long-Term Follow-Up in Patients with Right Ventricular Outflow Tract Tachycardia and Arrhythmogenic Right Ventricular Cardiomyopathy Who Underwent Catheter Ablation

Catheter ablation of ventricular tachyarrhythmia is a standard modality of treatment and is increasingly preformed. In our laboratory, a total 239 patients received mapping/ablation for VT from 2000 to 2010; the common types of VT were idiopathic right ventricular outflow tract tachycardia (RVOT-T, 43%) and arrhythmogenic right ventricular cardiomyopathy (ARVC, 19%). In between, we performed substrate mapping in 72 patients with optimal successful result. In these patients, substrate mapping can be applied to use to guide ablation, and predict the long-term clinical outcome. In all patients with RVOT-T fulfilling or not fulfilling the Task force criteria for ARVC, the presence of low voltage zone (<0.5 mV) in the ROVT free wall and RV free wall, and ablation lesions away from the pulmonary valve (near the body) had significant risk of VT recurrence. This study highlights the limitations of conventional criteria for identification of high risk RVOT-T patients with mild or atypical form of RV cardiomyopathy. With a follow-up period of 68±10 months, recurrence of ventricular arrhythmia was noted in 30% of patients. In patients with ARVC, long-term prognosis is favorable. ARVC patients who underwent catheter ablation were totally free of any rapid VT/VF during follow-up, and late occurrence of rapid VT/VF is very rare.