LONG-TERM RESULTS OF CATHETER ABLATION FOR IDIOPATHIC VENTRICULAR-TACHYCARDIA ORIGINATED FROM THE RIGHT-VENTRICULAR OUTFLOW

We performed catheter ablation in 10 consecutive patients with idiopathic monomorphic right ventricular tachycardia and studied the long-term outcome. All ventricular tachycardias had a left bundle branch block configuration with an inferior axis, and originated from right ventricular outflow. Antiarrhythmic drugs (3-6 drugs) had been ineffective in controlling ventricular tachycardia. The 2 patients who underwent direct-current ablation (2 shocks of 150 J) had no recurrence of ventricular tachycardia and did not require antiarrhythmic drugs during a follow-up of 56 and 51 months, respectively. Of the 8 patients who underwent radiofrequency ablation (30-40 watt, 20-40 sec, 2 - 15 application, using Inter Nova RA 50, 13.56 MHz), 1 patient had no rccurrence of ventricular tachycardias and did not require antiarrhythmic drugs, 4 patients had no recurrence of ventricular tachycardias but did require antiarrhythmic drugs, and 3 patients experienced recurrence of non-sustained ventricular tachycardia despite the use of antiarrhythmic drugs during a follow-up of 15 40 months. There were no complications except for cardiac perforation which occurred immediately after direct-current ablation in 1 patient. In conclusion, long-term success in preventing ventricular tachycardia was achievable with direct-current ablation, but this success was associated with serious risks, such as cardiac perforation. Radiofrequency ablation was safer than direct-current ablation, but had a lower long-term success rate.