Radiofrequency catheter ablation of frequent ventricular pre-mature contractions from left ventricular outflow tract

Objective:To observe the results of radiofrequency catheter ablation for frequent premature ventricular contractions(PVCs)originating from left ventricular(LV)outflow tract and to evaluate its feasibility and safety.Methods:Severely symptomatic frequent PVCs in eight patients were refractory to antiarrhythm drugs.Radiofrequency catheter ablation was performed in these patients when the site of PVCs origin was identified with pace mapping technique and activation-mapping.Results:Radiofrequency catheter ablation was success in seven patients.In which,a local activation time(31±8)ms earlier than the onset of PVCs on site of left ventricular outflow tract just beneath the left aortic valve was recorded in six patients,and 12-lead pace mapping ECG demonstrated concordance with the PVCs in 11-lead(one patient)to 12-lead(five patients);in a patient,a local activation time 33 ms earlier than the onset of PVCs was recorded in the aortic sinus.PVCs were not inducible in seven patients successfully performed radiofrequency ablation.During a follow up period of 3~21 months,no PVCs recurrence in this seven cases,and the symptoms of the patients was significantly improved.One patient with PVC origininating from LV outflow tract failed to radiofrequency catheter ablation because no find ideal ablation target.Conclusion:Radiofrequency catheter ablation is a safe and effective treatment for patients with frequent premature ventricular contractions originating from left ventricular outflow tract.