RADIOFREQUENCY CATHETER ABLATION OF SYMPTOMATIC VENTRICULAR ECTOPIC BEATS ORIGINATING IN THE RIGHT OUTFLOW TRACT

Ectopic activity originating in the right ventricular outflow tract is a frequent finding and may result in severe symptoms such as dyspnea, palpitations, and lack of physical capacity correlated with a low cardiac output. In 12 consecutive symptomatic and drug refractory patients, we performed a study with intracardiac mapping and ablation procedure. The origin of the ectopic beats was identified, and the ablation procedure was performed. Patients were examined by serial ECG, Holter ECG, bicycle ECG, echocardiography, and thoracic X ray. At baseline, the mean number of ectopic beats was 23,823 during Holter ECG. No other arrhythmias were present. Patients underwent basic electrophysiological study, mapping process, and ablation in a single procedure. Ablation was performed with a deflectable thermocoupled catheter with tip electrodes of 4 mm. Criteria for identification of the origin of the ectopic beats included pace mapping with 12 leads and earliest endocardial activation. One male patient suffered from myocarditis; the other 11 patients had no underlying structural heart disease. The mean age was 38 years. Ablation procedure with delivered temperature of 70 °C was successful in 11 of 12 patients eliminating the focus. The mean procedural time was 79± 34 minutes; mean fluoroscopy time was 13.8± 8.8 minutes; and mean number of applications was 4.4± 2.8. No adverse effects occurred during a follow-up period of 10 months after ablation. The mean number of ectopic beats per 24 hours after ablation was 317 ± 599 with a P value of 0.00024. The clinical symptoms improved in all but one patient. One patient had a recurrence after 2 months that could be successfully treated by a second procedure. In our experience, temperature guided radiofrequency catheter ablation is safe and effective for the treatment of patients with symptomatic ectopic activity of the right outflow tract. As long as we lack the experience of a greater patient cohort and a longer follow-up, only drug resistant and highly symptomatic patients should be selected.