Forest plot of intelligence (author/year/journal—CHD type). Forest plot of intelligence (author/year/journal—CHD type). TGA, d-transposition of the great arteries; VSD, ventricular septal defect; TOF, tetralogy of Fallot; ASD, atrial septal defect; CHD, congenital heart disease; ECMO, extracorporeal membrane oxygenation; V.d.Rijken, Van der Rijken; cath, catheterisation; surg, surgery; CA, circulatory arrest; CPB, cardiopulmonary bypass. Caroline Sterken et al. Open Heart 2015;2:e000255 ©2015 by British Cardiovascular Society