LEFT-TO-RIGHT SHUNT IN ATRIAL SEPTAL-DEFECT - QUANTIFICATION BY ECHOCARDIOGRAPHY

Time motion echocardiograms (ECHO) of 30 patients with atrial septal defect (ASD) and 36 individuals without heart disease (C) were comparatively studied to see whether parameters may be defined indicating the size of the left-to-right shunt (LRS). The diagnosis was proven by cardiac catheterization; in the patients with ASD the pulmonic-to-systemic blood flow ratios, Qp:Qs, ranged from 1.33 to 3.85:1, and pulmonary vascular resistance was normal. The ratio of the left (LVD) and right ventricular dimension (RVD), LVD:RVD, and the RVD indices of the patients with ASD were significantly different from those of the C:1.07±0.04 vs. 3.1±0.03 and 22.5±0.5 vs. 9.8±0.2 mm/m2 respectively (mean ±1 SEM), p≦0.001. These parameters and the abnormal interventricular septal motion in 84% of patients with ASD did not correlate with the size of the LRS. However, the ratio Qp:Qs between 1.33 and 3.85:1 linearly correlated with the ratio derived from the maximal diastolic opening of the tricuspid (TVO) and mitral valve (MVO), TVO:MVO, with a coefficient of r=0.76, p < 0.001. In each patient with ASD and a Qp:Qs ratio ≧ 1.4:1 the ratio TVO:MVO was > 1.15, while in the C TVO:MVO ranged from 0.7-1.13 with a mean of 1.02±0.01 (1 SEM). The data suggest that in patients with ASD a significant left-to-right shunt may be quantified by ECHO and that these patients may be separated either from patients with ASD and a small LRS and/or from normal subjects. © 1979 Springer-Verlag.