Epidemiology and diagnosis of ventricular septal defect in Malta.

Malta is a small island with minimal changes in its population, making it an ideal location for epidemiological and historical studies dealing with congenital heart malformations. Ventricular septal defect was studied retrospectively from 1930 to 1994. A sharp and significant decline in age at diagnosis was found, predating echocardiography. All defects are now diagnosed by echocardiography, which has resulted in an increased prevalence of this lesion as seen at birth, particularly of minor defects. The prevalence of ventricular septal defect from 1990 to 1994 was 3.85/1000 live births, with 3.03/1000 not needing surgery and 0.83/1000 requiring operative intervention. Half the defects closed spontaneously. The majority of ventricular septal defects overall, and those spontaneously closing, were muscular defects. The overall prevalence at birth was significantly higher than that reported in recent studies using similar methodologies, implying that the reported rate is more likely to be the true prevalence at birth of clinically detectable defects.