1. Department of Cardiology, Royal Brompton and Harefield Hospital (V.D.N., S.E.), Royal Brompton & Harefield NHS Trust, Imperial College London, United Kingdom
2. Department of Cardiology, Doncaster and Bassetlaw Hospitals NHS Foundation Trust, Doncaster, United Kingdom (V.D.N.).
3. Cardiac Morphology, Paediatrics (S.Y.H.), Royal Brompton & Harefield NHS Trust, Imperial College London, United Kingdom.