1. British Heart Foundation Centre of Research Excellence and National Institute for Health and Care Research Biomedical Research Centre at the School of Cardiovascular and Metabolic Medicine and Sciences, King’s College London, UK (S.M.E., M.R., D.P.).
2. University Medical Center Utrecht, Utrecht University; and Cardiovascular and Respiratory Physiology, University of Twente, Enschede, the Netherlands (D.W.D.).
3. Cardiothoracic and Vascular Anesthesia and Intensive Care, Azienda Ospedaliera Santi Antonio e Biagio e Cesare Arrigo, Alessandria, Italy (F.P.).
4. Department of Critical Care Medicine, Guy’s and St Thomas’ National Health Service Foundation Trust, London, UK (N.B., L.C.).
5. Departments of Critical Care and Cardiology, Royal Brompton and Harefield Hospitals, London, UK (S.P.).
6. National Heart and Lung Institute, Imperial College, London, UK (S.P.).
7. Cardiovascular Center, Tufts Medical Center, Boston, MA (N.K.K.).