Comparison of presystolic Purkinje and late diastolic potentials for selection of ablation site in idiopathic verapamil sensitive left ventricular tachycardia

Background: Idiopathic verapamil-sensitive left ventricular tachycardia (ILVT) is the most common form of idiopathic left ventricular tachycardia (VT). Different methods have been proposed for ablation of ILVT. Methods: Between June 2002 and February 2004, 15 patients (12 men; age 28+/-11 years, range 12 to 51) with ILVT underwent radiofrequency (RF) ablation at our center. We retrospectively assessed the significance of recording purkinje potential (PP) and late diastolic potential (DP) and its effect on selection of ablation target and number of RF application. Results: Sixteen VTs were observed. The clinical VT had either RBBB and left axis morphology (14 cases) or RBBB and right axis morphology (2 cases). The QRS duration during tachycardia was 124+/-12 ms and the tachycardia cycle length was 356+/-53 ms. DP and PP were recorded at the targeted area for RF ablation in 11 and 9 patients respectively. The PP-Q interval, DP-Q interval and DP width were 18+/-4, 53+/-18 and 14+/-8 ms, respectively. The number of RF application was 7.2+/-4.3. Fewer applications were needed in whom RF ablation was initially targeted to PP (with or without DP) recording site (10 patients, 4.7+/-1.8) compared to those targeted to DP recording site (5 patients, 12.2+/-3.3) (P<0.05). Conclusion: Compared to DP alone, earliest PP (with or without concomitant DP) might be superior for selection of target site of RF ablation in patients with ILVT.