1. Cardiac Pacing and Electrophysiology, Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
2. Department of Cardiology, New York University Langone Medical Center, New York, NY, USA
3. Department of Cardiology, Akron General Hospital, OH, USA
4. Clinical Studies, Biotronik, Lake Oswego, OR, USA
5. Department of Cardiology, University of Pennsylvania, PA, USA