Radiofrequency ablation of the bundle of His was performed in 33 patients with intractable atrial arrhythmias (fibrillation in 23, flutter in seven, atrial tachycardia in three). Complete AV block was produced in 30 patients, and clinically satisfactory incomplete block in another two. All were subsequently treated by pacemaker. The ablation was a failure in one patient with hypertrophic cardiomyopathy. Today ablation can be targeted at atrial tachycardias and flutter, and ablative modification of the AV node can reduce ventricular rate in chronic atrial fibrillation. However, His bundle ablation is still the treatment of choice in drug refractory atrial fibrillation when no other measure can provide adequate rate control.