Spontaneous Closure of Physiologically Advantageous Ventricular Septal Defects

The clinical and pathological features of two cases in which physiologically advantageous ventricular septal defects closed spontaneously are presented. The first patient, with tricuspid atresia, Type I(c), developed symptoms and signs of increasing systemic hypoxemia, decreasing pulmonary blood flow, and a systolic murmur of decreasing intensity. His ventricular septal defect, previously demonstrated angiocardiographically, could not be found at autopsy; it is presumed to have closed by fusion of its muscular rims with subsequent covering by endocardial proliferation. The second patient, with a double-outlet right ventricle, demonstrated progressive left ventricular enlargement and congestive failure despite increasing pulmonary vascular resistance. Postmortem examination showed that this defect was sealed by adherence of the septal leaflet of the tricuspid valve to the edges of the defect. Appreciation of the true nature of the changing anatomical situation would have resulted in more rational effective therapeutic approaches.The cases presented and review of pertinent literature contribute to more complete understanding of circumstances surrounding the spontaneous closure of ventricular septal defects.