1. Arrhythmia Unit, Cardiology Department; Ramón y Cajal Hospital; Madrid Spain
2. Medtronic Ibérica; Madrid Spain
3. Txagorritxu Hospital; Vitoria Spain
4. Virgen de la Victoria Hospital; Málaga Granada Spain
5. Santa Creu i Sant Pau Hospital; Barcelona Spain
6. Clinic of Valladolid Hospital; Valladolid Spain
7. Donostia Hospital; Donostia Spain
8. Canarias Hospital; Santa Cruz de Tenerife Spain
9. Vigo Hospital; Vigo Spain
10. Puerta de Hierro Hospital; Madrid Spain
11. Complejo Hospitalario Universitario de Granada; Granada Spain