Echocardiographic assessment of Qp/Qs in children with atrial septal defect or partial anomalous pulmonary venous connection.

In 24 children with atrial septal defect of the secundum type and/or partial anomalous pulmonary venous connection, the pulmonary to systemic blood flow ratio (Qp/Qs) was estimated by echocardiography. Using M-mode echocardiography, right ventricular diameter (RVD), left ventricular diameter (LVD), total cardiac diameter (TCD) and aortic root (AOR) were measured, and the following 5 indices were obtained: RVD/LVD, RVD/TCD, RVD/AOR, RVD/BSA (body surface area) and TCD/BSA. The single linear correlation coefficients between these 5 indices and Qp/Qs, obtained by the Fick method during cardiac catheterization, were 0.88, 0.80, 0.74, 0.75 and 0.55, respectively. Thus, RVD/LVD ratio was the most sensitive echocardiographic index to assess Qp/Qs in these children. Clinically, however, the multiple linear regression equation derived from 3 indices (RVD/BSA, RVD/LVD and TCD/BSA) might be more useful (r = 0.89). Although the abnormal motion of the interventricular septum was analyzed, the quantification of this motion as an index of Qp/Qs was difficult.