Treatment of tachycardias associated with the Wolff-Parkinson-White syndrome by transvenous electrical ablation of accessory pathways.

Three patients with tachycardias associated with the Wolff-Parkinson-White syndrome had failed to respond to antiarrhythmic drugs and underwent transvenous ablation of accessory pathways. Intracardiac studies located the site of accessory pathway to the septum in two patients and mid-posterobasal left atrioventricular junction in one. Ablation was performed by positioning an electrode lead as close as possible to the accessory tract and delivering shocks of 50 to 100J using a conventional defibrillator. In all patients the accessory pathway was abolished after the first three shocks. In two patients followed for four and nine months there was no recurrence of tachycardia or pre-excitation. The other patient developed pre-excitation again three weeks later and repeat ablation was performed. This patient has been followed for six months with no evidence of a recurrence of pre-excitation. This method may provide a valuable alternative to pacemaker and surgical treatment in selected patients with drug resistant arrhythmias associated with accessory atrioventricular connexions.