1 Royal Brompton Hospital, London, SW3 6NP, United Kingdom. Electronic address: [email protected].
2 University College London Hospital, London, NW1 2BU, United Kingdom.
3 Royal Brompton Hospital, London, SW3 6NP, United Kingdom.
4 Royal Brompton Hospital, London, SW3 6NP, United Kingdom; National Heart and Lung Institute, Imperial College London, London, SW3 6LY, United Kingdom.