1 Robertson Centre for Biostatistics and Clinical Trials, University of Glasgow, Glasgow, Scotland, United Kingdom; National Heart and Lung Institute, Imperial College, London, United Kingdom. Electronic address: john.cleland@glasgow.ac.uk.
2 Department of Cardiology, University of Hull, Kingston-upon-Hull, United Kingdom.
3 Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom.