Between 1985 and 1990, 1242 patients with supraventricular arrhythmias were followed-up at our Institution. Six hundred and twenty patients had atrial fibrillation or flutter; 7 of them (1%) underwent modulation of atrioventricular conduction. Four hundred and twenty-eight patients had ventricular preexcitation; in 23 (5%) surgical or transcatheter ablation of an accessory pathway were performed. Atrioventricular node reentrant tachycardias were diagnosed in 111 patients; 8 patients (7%) underwent antitachycardia pacemaker implantation. Surgical and catheter ablative techniques eliminate the substrate of the tachycardia; death and complete A-V block (paraseptal pathways) are at this moment rarely reported. Antitachycardia pacemakers do not offer a definitive therapy. For their safeness and effectiveness they are still indicated in patients with A-V node reentrant tachycardias, until technological development will reduce the risks of ablative techniques.