A biatrial pacemaker was inserted in a 68-year-old female with paroxysmal atrial fibrillation and atrial flutter refractory to antiarrhythmic drugs based on a sick-sinus-syndrome and concomitant interatrial conduction delay. One electrode positioned in the right atrium and another electrode located in the coronary sinus were connected to a dual-chamber pacemaker. The electrode in the right atrium was connected to the atrial channel, the electrode in the coronary sinus to the ventricular channel. The pacemaker was programmed in DDD-mode with an AV-delay of 30 ms. Under a chronic antiarrhythmic medication with 160 mg sotalol per day there was no evidence for recurrent episodes of atrial tachyarrhythmias in the patient's history, 24-h-Holter-ECG, nor in the memory of the pacemaker during a follow-up of 8 months.