1. West of Scotland Regional Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, United Kingdom (D.T.Y.A., A.K., R.S., D. Collison, C.B.).
2. British Heart Foundation, Glasgow Cardiovascular Research Centre, School of Cardiovascular and Metabolic Health (D.T.Y.A., A.K., R.S., C.B.), University of Glasgow, United Kingdom.
3. Department of Cardiology, University Hospital Hairmyres, Lanarkshire, United Kingdom (D.T.Y.A., D. Carrick, R.J.M.).
4. Robertson Centre for Biostatistics, School of Health and Wellbeing (A.M.), University of Glasgow, United Kingdom.