This paper reports the initial results of radio-frequency ablation of accessory pathways in 3 consecutive patients with left lateral bundles of Kent and indications for accessory pathway ablation. A modified Polaris catheter was used with a wide distal tip through which the radio-frequency current was delivered by a generator with an intensity of 0.5 Ampères and a potential of 50 Volts, i.e. power of 25 Watts. The appearances of ventricular preexcitation disappeared in all cases and did not reappear during follow-up of 7 to 28 days. These preliminary results are encouraging. Further studies with longer follow-up are required to confirm the safety and efficacy of this new promising technique of ablation.