Predictive value of the echocardiographic left atrial dimension in isolated ventricular septal defect

Echocardiographic left atrial dimension has been reported to correlate with left-to-right shunt (Qp/Qs) in children with isolated ventricular septal defect (VSD) or patent ductus arteriosus (PDA). In 17 children with isolated VSD, we prospectively compared Qp/Qs with the ratio of echocardiographic left atrial dimension to aortic root diameter (LAD/Ao) and with the left atrial dimension corrected for body surface area (LAD/M2). The correlation between LAD/Ao and Qp/Qs was not statistically significant (r = 0.49, p > 0.05). The LAD/M2 correlated significantly with Qp/Qs (r = 0.66, p < 0.01); however, prediction intervals were excessively wide. Our findings indicate that it is inappropriate to predict Qp/Qs in these patients from echocardiographic LAD.