UNLABELLED The aim of the study was to evaluate the efficacy of radiofrequency (RF) ablation with anatomical approach in treatment of atrioventricular nodal reentrant tachycardia (AVNRT). The study group consisted of 45 patients (pts), 34 F, 11 M, mean age 46.3 +/- 11.8 y in whom AVNRT was diagnosed. In all the pts successful RF ablation of slow pathway was performed. Ablation catheter was positioned under fluoroscopy control in the bottom part of Koch's triangle using anatomical approach. Mean number of RF applications during the procedure was 6.9 +/- 7.5. During successful RF application accelerated junctional rhythm or junctional beats were present in 36 pts (80%) and in 6 pts (13.3%) respectively. Slow pathway potentials (SPp) were recorded at successful ablation site in 8 pts (17.8%). Follow-up time after ablation was mean 15.5 +/- 10.7 m. In 2 pts (4.4%) tachycardia recurred after successful procedure. In 1 pt episodic asymptomatic second degree atrioventricular block developed 4 weeks after ablation. CONCLUSIONS 1) slow pathway RF ablation using anatomical approach is highly effective in the treatment of AVNRT, 2) SPp have a low sensitivity as indicators of successful ablation site.