This paper reports the authors' preliminary experience in catheter ablation by radiofrequency current of 46 accessory atrioventricular pathways in 45 symptomatic patients with supraventricular tachyarrhythmias resistant to medical therapy. With an average follow-up period of 5.5 +/- 4 months the global success rate was 80%, ranging from 96% in left lateral to 33% in antero septal accessory pathways. It increased from 65% in the first 20 patients to 88% in the last 25 patients. The average duration of radioscopy was significantly shorter in left lateral pathways than in other localisations (p < 0.02); it was also shorter when ablation was successful. Complications were observed in 4 patients (9%) and included one complete atrioventricular block and 3 femoral arterial lesions. Anaesthetic assistance was required in 14 cases (31%), either at the patient's request or to allow reduction of atrial fibrillation. Percutaneous catheter ablation of accessory atrioventricular pathways with radiofrequency current is effective and gives good results; very strict selection of initial patients and the respect of certain conditions taking into account the experience of the medical team, the technically difficult approach of certain accessory pathways and the risks of ablation of pathways running near the atrioventricular node or His bundle, are necessary for successful results when learning this technique.