Aims To establish the frequency of complications in adults with small
ventricular septal defects, which have not undergone surgery. Methods
and Results One hundred and eighty-eight adults aged 17-72 (mean, 29.2
) years with a small ventricular septal defect were studied. They were
referred to a national cardiac centre (National Heart Hospital) and s
pecialized grown-up congenital heart unit. One hundred and thirty-eigh
t were examined in 1994-95. Fifty patients (26.6%) had additional card
iovascular lesions, most commonly a bicuspid aortic valve and/or coarc
tation. Spontaneous closure occurred in 19 (10%) between the age of 17
and 45 (mean, 27) years. Twenty-one (11.2%) had infective endocarditi
s. Aortic regurgitation developed in 37 (19.7%) patients; it was sever
e in nine. Atrial arrhythmias (supraventricular tachycardia or atrial
fibrillation) occurred in 12 patients. In four patients, atrial fibril
lation produced severe right-sided congestion with a left ventricular
to right atrial shunt and haemodynamic features suggesting restrictive
cardiomyopathy'. Four patients had ventricular arrhythmia. Disproport
ionate left ventricular enlargement on echocardiography and/or chest r
adiography was present in 26 (13.8%) without lesions to account for it
. Conclusions Eighty nine patients (47%) aged 17-44 (mean, 26.8) years
had no complications through many years, while spontaneous closure oc
curred in 19 (10%) during adulthood. Forty-six (25%) had serious compl
ications: infective endocarditis (11%), progressive aortic regurgitati
on (5%), age-related symptomatic arrhythmias (8.5%) and atrial fibrill
ation the commonest. Accepting that there may be a referral bias for t
hose with complications, the course of a small ventricular septal defe
ct is not necessarily benign during adult life.