Increase in diameter of ventricular septal defect and membranous septal aneurysm formation during the infantile period

Serial changes in diameters of ventricular septal defect (VSD), and in the formation patterns of membranous septal aneurysm (MSA), were evaluated usin g two-dimensional (2-D) echocardiography during the infantile period. We st udied 65 patients with VSD, who were classified into three groups by clinic al feature. The patients with severe respiratory symptoms and significant f ailure to thrive were classified as group A (n = 15). The patients with no respiratory symptoms and mild or moderate failure to thrive were classified as group B (n = 38). Group C had no or trivial clinical symptoms and no ne ed for surgical repair (n = 12). Group A showed rapid enlargement of VSD du ring early infancy. In this group, the mean diameter of VSD at age 5 months was 75% larger than the mean diameter at age 1 month (an increase of 5.5 t o 9.6 mm; p < 0.05). The other two groups (B, C) showed a slower enlargemen t as compared with group A. The rapid enlargement of VSD in group A seemed to induce the rapid increase in pulmonary blood flow with severe clinical s ymptoms. We suggest that careful observation of the changes in VSD diameter s by periodic echocardiography is important in predicting the clinical cour se and in deciding the operation indication.