Echocardiographic assessment of left-to-right shunt volume in children with ventricular septal defect.

Echocardiograms were performed in 20 infants and children with isolated ventricular septal defects (VSD) undergoing cardiac catheterization. The magnitude of the left-to-right shunt was expressed as the pulmonary-to-systemic flow ratio (Qp/Os) and was compared to a ratio of the echographic left atrial (LA) diameter to the aortic root (Ao) diameter (LA/Ao). The Qp/Qs was also compared to LA/m2. Thirty-three normal children served as controls. The LA/m2 and Ao/m2 were significantly larger in normal infants under one year of age than in children above one year. The LA/Ao, however, was not influenced by age or size. A strong linear relationship was found between Qp/Qs and the LA/Ao (r = 0.96). The LA/Ao measurement appears to be helpful in the noninvasive assessment of the left-to-right shunt in patients with VSD.