Catheter ablation of ventricular outflow tract arrhythmias using an electroanatomic mapping system

BACKGROUND: In some patients with arrhythmias originating from the ventricular outflow tract, catheter ablation may be considered for curative treatment. The conventional ablation procedure may be limited particularly in cases with nonsustained arrhythmias. Only little information is available about three-dimensional electroanatomic mapping combined with the cooled radiofrequency (RF) catheter ablation technique in the treatment of such arrhythmias. PATIENTS AND METHODS: 17 symptomatic and drug-refractory patients were included into this study. Using an electroanatomic mapping system (CARTO), activation mapping was obtained in twelve patients during ventricular tachycardia (VT) or ventricular ectopic beats. In five cases with nonsustained arrhythmias pace mapping during sinus rhythm was performed. The aim was to identify the precise localization of the arrhythmia origin and to abolish its activity by cooled ablation. RESULTS: Procedure time was 117 +/- 35 min, fluoroscopy time totaled 17 +/- 13 min. Ablation was performed with a mean of 7 +/- 5 ablation pulses. In 15 patients (88%) ablation of the clinical VT was acutely successful. During a follow-up of 9 +/- 9 months, two patients had a recurrence of the clinical VT. In one of these cases a successful reablation was performed. No major complications were observed. CONCLUSION: Electroanatomic mapping combined with focal cooled ablation strategy is a safe method to treat ventricular outflow tract arrhythmias effectively.