The catheter ablation usin radiofrequency(RF) energy in patients with atrioventricular nodal reentrant tachycardia(AVNRT) and atrioventricular reentrant tachycardia(AVRT) ahs been proved as a safe and effective nonpharmacologic therapeutic modality. The purpose of our study was to evaluate the success rate and complications of the initial experience and to determine the extent of myocardial damage of RF catheter ablation.

Electrophysiologic study was performed with the standard technique. Twenty five patinents(M:F=16:9, mean age:42 years old) underwent RF catheter ablation in St. May's Hospital from April to December in 1994. The RF generator in this study was RFG-3D model and catheters were 6F or 7F steerable catheters with 4mm kistal tip. In order to evaluate the extent of myocardial damage the WBC count, LDH, CK, and CK-MB fraction were checked before and after RF catheter ablation and the Tc99m myocardial scintigraphy was performed within 72 hours of the porcedure.

Six of twenty five patients had AVNRT, in which the success rate of selective ablation of the slow pathway was 83.8%. Nineteen patients with AVRT had one accessory pathway. The ablation success rate of 14 accessory pathways in left free wall location was 85.7%, and that of 3 in left posteroseptal location was 66.6%. Two right sided accessory pathways were not ablated successfully. The level of CK-MB fraction after ablation was within normal limit. Only one case revealed grade 2 of hot spot in Tc99m myocardial scintigraphy.

The RF catheter ablation in patients with AVNRT and AVRT is a safe and effective nonpharmacologic therapeutic modality. But right sided accessory pathways are more difficult to ablate than left sided accessory pathways, requiring more experiences and better technique. The extent of myocardial damage after RF catheter ablation reveals relatively minimal by cardiac enzyme study and Tc^99mmyocardial scintigraphy.