Efficacy of an implanted automatic defibrillator which had induced atrial fibrillation.

A 54 year old man with refractory life threatening ventricular tachycardia was given an automatic defibrillator. The initial system was a transvenous defibrillator coil electrode and this was later modified by implantation of two patch electrodes at thoracotomy. The modified system successfully controlled ventricular tachycardia. On one occasion reversion of ventricular tachycardia by the defibrillator precipitated atrial fibrillation, a previously unreported side effect.