Electrocardiographic predictors of long-term outcomes after radiofrequency ablation in patients with right-ventricular outflow tract tachycardia.

AIMS: The objectives of this study were to identify electrocardiographic (ECG) predictors of long-term outcomes after radiofrequency (RF) ablation in patients with right-ventricular outflow tract (RVOT) tachycardia. METHODS AND RESULTS: We correlated ECG characteristics with RF ablation outcomes in 144 patients with RVOT tachycardia who underwent RF ablation for >1 year. Unfavourable RF ablation outcomes were predefined as unsuccessful RF ablation or recurrence of tachycardia requiring repeated ablation. RF ablation was not successful in 11 (7.6%) patients and 16 (12%) patients had arrhythmia recurrence requiring repeated ablation. Average follow-up time was 72.2+/-28.4 months. Selected parameters from univariate analysis included number of RF applications, pacemapping, application of bonus burn, procedure time, monophasic R-wave in lead I, QS pattern in leads I and aVL, QRS duration in leads II and V(2), and right axis deviation, in ventricular tachycardia. From logistic regression analysis, only monophasic R-wave in lead I remained in the final equation (P=0.004, odds ratio 12.9). CONCLUSION: Monophasic R-wave in lead I during RVOT tachycardia is associated with unfavourable outcomes after RF ablation. This finding may help clinicians in the selection of patients for RF ablation and for the prediction of RF ablation outcome.

A randomized clinical trial of the efficacy of radiofrequency catheter ablation and amiodarone in the treatment of symptomatic atrial fibrillation.

The limited efficacy and proarrhythmic risks of antiarrhythmia agents have resulted in alternative therapeutic approaches. Radiofrequency ablation has been reported to be an effective treatment of patients with atrial fibrillation. However, there is no randomized clinical trial comparing drug and radiofrequency ablation. The authors randomized 30 patients with chronic atrial fibrillation refractory to medication into amiodarone and radiofrequency ablation. The primary objective of this study was to compare the efficacy of amiodarone and radiofrequency ablation in the maintenance of sinus rhythm at 1 year after randomization. Pulmonary vein isolation and linear ablation of right atrium was the technique used for radiofrequency ablation. There were no significant differences in baseline patient characteristics between the 2 groups. The results of this study showed that the probability of free from atrial fibrillation was better in the radiofrequency ablation group compared to amiodarone (78.6% in the ablation group and 40% in the amiodarone group, p = 0.018). Radiofrequency ablation results in a significant reduction in symptoms relating to atrial fibrillation and a significant improvement in quality of life, whereas amiodarone had no significant effect on symptoms and quality of life. There was an ischemic stroke as a major complication related to radiofrequency ablation. Amiodarone was associated with adverse effects in 46.7 per cent of patients and needed discontinuation in 1 patient. In conclusion, radiofrequency ablation is an effective alternative treatment in patients with atrial fibrillation refractory to medication.

Transcatheter coil occlusion of small patent ductus arteriosus: experience at Siriraj Hospital.

UNLABELLED: Transcatheter coil occlusion of small-to-moderate-size patent ductus arteriosus (PDA, < 3.5 mm) is well established as a procedure of first choice in many institutions. Its much lower cost compared with surgical ligation or other devices makes it an attractive option, especially in Thailand. PATIENTS AND METHOD: Between September 1995 and June 2000, all patients diagnosed with PDA with audible murmur and echo-Doppler confirmation of diameter less than 3.5 mm were scheduled for transcatheter coil occlusion at the Department of Pediatrics, Faculty of Medicine Siriraj Hospital. The hemodynamic studies were obtained both pre and post occlusion. The immediate and late outcome, including complication were assessed. RESULTS: A total of 77 cases, 78 procedures of transcatheter PDA coil occlusion were performed. Seventy cases (90.9%), comprised of 19 males (27.1%) and 51 females (72.9%) were successfully deployed with coils. The remainder were unsuccessfully deployed and later referred to surgery. The median age of the successful group was 6 years and 6 months and median weight was 16.5 kg. Twenty cases (28.6%) had other associated intra and extracardiac anomalies. All patients were asymptomatic, except one case having bronchopulmonary dysplasia (BPD) from prolonged ventilation. Single-coil occlusions were performed in 74.3 per cent and double-coil occlusions in 25.7 per cent. Conventional 0.038-inch Gianturco coils were deployed in 86.5 per cent. The mean procedure time was 78.1 +/- 35.1 minutes. The mean fluoroscopic time was 20.2 +/- 15.6 minutes. The total complete occlusion rate was 87.7 per cent. Tiny residual flow of PDA was demonstrated by follow-up echocardiogram in 12.3 per cent. Seven per cent of the patients were lost to follow-up. There was no significant difference in PDA size and hemodynamics between the groups of patients with complete occlusion and having residual shunt. Minor complications occurred in 12.9 per cent, including mild left pulmonary artery stenosis (10%), coil embolization to distal pulmonary artery (8.6%), slippage of catheter with coil (2.9%) and decreased dorsalis pedis pulse (1.4%). One late death was found in a BPD patient from pneumonia 2 months after the procedure. CONCLUSION: Transcatheter coil occlusion of PDA is as effective, feasible, safe and less costly than surgical ligation. With improvement in technique and device selection and appropriate case selection, there should be an increase rate of complete occlusion and a decrease in complications.