1. Department of Cardiology São João Hospital Centre, E.P.E. Alameda Prof. Hernâni Monteiro Porto 4200‐319 Portugal
2. Department of Surgery and Physiology, Cardiovascular R&D Centre, Faculty of Medicine University of Porto Porto Portugal
3. Department of Cardiothoracic Surgery São João Hospital Centre, E.P.E. Porto Portugal
4. Department of Anaesthesiology São João Hospital Centre, E.P.E. Porto Portugal