1. From the University of Birmingham Institute of Cardiovascular Sciences, City Hospital, United Kingdom (J.S.C., G.Y.H.L., D.K.); Department of Maternity and Perinatal Medicine, Sandwell and West Birmingham Hospitals NHS Trust, United Kingdom (J.S.C., F.T.); Epsom and St Helier University Hospitals NHS Trust, Epsom, United Kingdom (R.G.); and Department of Cardiology, University Hospitals Birmingham NHS Foundation Trust, United Kingdom (R.P.S., D.K.).