Background Ventricular septal defects (VSDs) are the most common congenital heart defects (CHDs). Previous studies indicate an increased risk of endocarditis, aortic regurgitation, left ventricular outflow tract obstructions, pulmonary hypertension, arrhythmias and sudden death in patients with isolated VSDs. The present nationwide cohort study reports mortality and cardiac complications requiring hospitalisation or intervention in children with isolated VSDs.

Methods and results Medical information concerning all 943 871 live births in Norway in 1994–2009 was retrieved from the Medical Birth Registry of Norway, the Cardiovascular Disease in Norway project, the Oslo University Hospital's Clinical Registry of Congenital Heart Defects and the Norwegian Cause of Death Registry. Isolated VSDs were identified in 3495 children without known chromosomal aberrations or extracardiac malformations. Surgical or catheter-based treatment of VSD was performed in 181 (5.2%) cases. Twelve (0.3%) children with VSDs died before 2013. There was no operative mortality, and no excess mortality in children with isolated VSDs compared with children without VSDs (adjusted HR 0.8 (0.5 to 1.4), p=0.48). The following conditions were recorded as possible cardiac complications of the VSDs: endocarditis in 3 children (0.9‰), aortic regurgitation in 12 children (3.4‰), left ventricular outflow tract obstructions in no children (0.0‰), pulmonary hypertension in 1 child (0.3‰) and arrhythmias in 16 children (4.6‰).

Conclusions The entire group of children with isolated VSDs had a favourable prognosis without excess mortality. Cardiac complications requiring hospitalisation or intervention, including endocarditis, aortic regurgitation, left ventricular outflow tract obstructions, pulmonary hypertension and arrhythmias, were infrequent during childhood.

Trial registration number NCT02026557.