1. Cardioangiologisches Centrum Bethanien (CCB)Frankfurt Academy For Arrhythmias (FAFA)Frankfurt am Main Germany
2. Department of Cardiology, Medizinische Klinik IIIAgaplesion Markus KrankenhausFrankfurt am Main Germany
3. Department of Cardiology and ElectrophysiologyAcibadem City Clinic Cardiovascular CenterSofia Bulgaria