From 24.10.1969 to 31.12.1986, seventeen years, 1274 infants and children with proven isolated ventricular septal defect were observed and followed in Pediatric Cardiology of Santa Marta Hospital. There were 659 males and 615 females, ranging from 3 days to 12 years, born in portuguese territory and without syndromes. As early detection and referring is crucial to prevent pulmonary vascular disease with fixed pulmonary arterial resistance, the annual variation of the referring age was studied. The results improved since 1972 with a steady faster improvement during the last 7 years of the study.