Radiofrequency catheter ablation for management of refractory ventricular ectopic beats originating from right ventricular outflow tract

Objective:To observe the effect of radiofrequency catheter ablation on frequent ventricular ectopic beats originating from right ventricular outflow tract(RVOT).Methods:Twelve patients with frequent and severely symptomatic ventricular ectopic activity originating from RVOT were selected. The mean frequency of ventricular ectopic activity was (24 786±7 227)beats/24 h documented by ambulatory electrocardiographic (ECG) monitoring. These patients had previously been unable to tolerate or had been unsuccessfully treated with antiarrhythmic drugs. Radiofrequency catheter ablation was performed in these patients when the site of ventricular ectopic activity was mapped by pace mapping technique.Results:In 10 patients, frequent ventricular ectopic beats were successfully eliminated by catheter delivered radiofrequency energy at the site where the QRS complex waves mapped by pace mapping were identical to spontaneous ventricular ectopic beats in 12 lead surface ECG. The successful ablation sites were at septum of RVOT in seven patients, and at free wall in three patients.The same therapeutic measure failed in two patients whose QRS complex waves were identical to spontaneous ventricular ectopic beats only in 11 lead surface ECG. Ablation success rate was 83.3 %. The mean frequency of ventricular ectopic activity was respectively (2±3)beats/24 h and (4±11) beats/24 h as documented by ambulatory ECG monitoring one week and 5～15 months after the successful ablation. During follow up, there were no recurred ventricular ectopic beats in ten successful patients. No complications encountered.Conclusion:Radiofrequency catheter ablation is an effective and safe treatment for ventricular ectopic activity originating from RVOT. It may be a reasonable alternative for the treatment of severely symptomatic, drug resistant or intolerable ventricular ectopic activity in patients.