1. Cardiology, Hôpital René Muret, Hôpitaux Universitaires de Paris Seine Saint-Denis , Avenue du docteur Schaeffner , France
2. Department of Cardiology, Medical University of Pleven , 1, Kl. Ohridski Street, Pleven , Bulgaria
3. Cardiology Department, Vall d'Hebron Hospital, and Universitat Autònoma de Barcelona , CIBERESP , Spain
4. Servicio de Cardiología, Hospital Universitario de La Princesa, Universidad Autónoma de Madrid , Spain