1. University of Edinburgh Centre for Cardiovascular Science, Royal Infirmary of Edinburgh, United Kingdom (A.J.F., M.B.J.S., D.E.N., N.L.W.).
2. Centre for Genomics and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, United Kingdom (T.J.A.).
3. Scottish Adult Congenital Heart Disease Service, Golden Jubilee National Hospital, Clydebank, Glasgow, United Kingdom (N.L.W.).