1. Department of Electrophysiology, Alfried Krupp Hospital , Essen , Germany
2. Department of Medicine, Witten/Herdecke University , Witten , Germany
3. Department of Pulmonology, Alfried Krupp Hospital , Essen , Germany
4. Department of Gastroenterology, Alfried Krupp Hospital , Alfried-Krupp-Str. 21, 45131 Essen , Germany