Predictors for Successful Ablation of Right- and Left-Sided Idiopathic Ventricular Tachycardia

This study reports on predictors for successful radiofrequency (RF) ablation of idiopathic ventricular tachycardia (VT) in 48 patients—35 with right ventricular (RV) outflow tract and 13 with left ventricular VT. In RV outflow tract idiopathic VT, RF ablation was successful in 29 of 35 patients (83%). The following information allowed differentiation between patients with and without a successful RF ablation: >1 induced VT morphology (0 vs 3); presence of delta wave-like beginning of the QRS (2 vs 3) and ≥11 of 12 leads showing a “match” between the clinical VT and the pacemap (28 vs 1). Endocardial activation times were not different between both groups (−15 ± 18 vs −4 ± 5 ms). In left ventricle idiopathic VT, RF ablation was successful in 12 of 13 patients (92%). In patients who underwent successful ablation, 1 VT morphology was induced and no delta wave-like beginning of the QRS was present; a correlation between clinical VT and the pacemap ≥11 of 12 leads was found and the endocardial activation time preceded the QRS (range of −5 to −58 ms [mean −30 ± 14]). Purkinje activity was observed in 5 of 7 patients with an idiopathic VT originating from the inferoposterior region but not from the inferoapical region of the left ventricle. Four patients (14%) with RV outflow tract idiopathic VT had recurrence during a mean follow-up of 2 to 50 months (mean 30 ± 12). Thus, (1) in RV outflow tract idiopathic VT a good pacemap was more important than an early endocardial activation time; (2) an optimal pacemap as well as an early endocardial activation time were important predictors for successful ablation of the left ventricle idiopathic VT; (3) Purkinje activity was recorded in VTs arising in the inferoposterior region of the left ventricle; and (4) factors for unsuccessful ablation for idiopathic VT were >1 induced VT morphology, a delta wave-like beginning of the QRS, and a VT/pacemap correlation <11 of 12 leads. Idiopathic VT can be successfully ablated with both immediate and long-term success.