1. Department of Physiology and Cardiothoracic SurgeryCardiovascular Research and Development UnitFaculty of MedicineUniversity of PortoPortoPortugal
2. Department of MedicineBrigham and Women's HospitalBostonMassachusettsUSA
3. MedStar Heart InstituteWashington Hospital CenterWashington, DCUSA
4. Department of CardiologyChildren's National Medical CenterWashington, DCUSA
5. Department of CardiologyBoston Children's HospitalBostonMassachusettsUSA