Of 182 children who in the years 1990 to 1995 underwent surgical closure of a congenital VSD at Aarhus University Hospital (AUH), Denmark, a small group of 20 is randomly selected to participate. These children form a homogenous group of patients comparing surgeons, anesthetists, surgical procedures and post-surgical period. An equal amount of healthy controls, matched on age and gender, form the control group.