The potential role of local voltage potentials in right ventricular outfl ow tract arrhythmias: 47 cases with ventricular arrhythmias originating from right ventricular outfl ow tract

OBJECTIVE: The object of this study was to investigate the possible role of local voltage potentials (LVPs) in mapping the ventricular arrhythmias originating from right ventricular outflow (RVOT). METHODS: Forty-seven patients with RVOT VAs (ventricular arrhythmias), referred for radiofrequency catheter ablation to our hospital, were analysed retrospectively for the prevalence, characteristics and electrophysiological evaluation of the LVPs recorded in successful and unsuccessful ablation sites. RESULTS: Radiofrequency ablation was successful immediately in all the 47 cases. Catheter ablation was performed at a mean of 8 +/- 6 sites per patient. There were 58 effective ablation sites, 5 cases with changing morphology of ventricular arrhythmias (VAs), and 318 invalid ablation sites. Activation times at effective ablation sites were slightly earlierthan those at invalid ablation sites (-28 +/- 8 ms vs-24 +/- 7 ms, P < 0.05). The LVPs appeared during VAs in 47 sites of the 58 effective ablation sites (81.0%), far more than the 22 sites of the 318 invalid ablation sites (6.9%) (P < 0.01). In two cases VAs recurred during follow-up. They received a second catheter ablation. CONCLUSIONS: Local ventricular potentials can be recorded in most patients with idiopathic VAs originating from the right outflow tract.The local potentials may facilitate successful radiofrequency ablation.