Torsades de pointes following radiofrequency catheter His ablation.

A case of polymorphic ventricular tachycardia torsade de pointes type, appearing in a 70-year-old female following radiofrequency catheter His ablation, is presented. The substrate was slow rate with ventricular bigeminy and QT prolongation which appeared after ablation. The same phenomenon reappeared after permanent VVIR pacemaker implantation with a basal rate of 55 beats/min. One episode of polymorphic ventricular tachycardia deteriorated into ventricular fibrillation, requiring a 360-J DC shock. Raising the pacemaker rate to 80 beats/min abolished the arrhythmias.