Echocardiographic prediction of left-to-right shunt with atrial septal defects

We investigated the ability of transthoracic echocardiography to predict a ratio of pulmonary to systemic now (Qp/Qs) greater than or equal to1.5 in p atients with secundum atrial septal defects. The 44 study patients included 31 patients undergoing catheterization for device closure of atrial septal defects and 13 additional control patients with normal echocardiograms (me dian age 7.8 years, mean age 15.9 years, range 1.5 to 69 years). Right atri al end-systolic area, right ventricular end-diastolic volume, and the ratio of pulmonary annulus diameter to aortic annulus diameter were determined f rom standard transthoracic echocardiographic views. The 26 subjects in the shunt group had Qp/Qs between 1.5 and 3.0. The control subjects included th e 5 catheterization patients with QP/Qs between 0.9 and 1.2 and the 13 pati ents that did not undergo catheterization with assumed Qp/Qs = 1. The shunt patients had significantly increased median-indexed right atrial area (13. 8 versus 8.5 cm(2)/M-2, P < .0001), median-indexed right ventricular volume (85 versus 39 mL/M-2, P < .0001), and median ratio of pulmonary valve annu lus to aortic valve annulus (1.26 versus 1.13, P = .008) compared with cont rols. indexed right ventricular volume was the best predictor of significan t shunt. A combination of right ventricular volume and right atrial area id entified subjects with Qp/Qs greater than or equal to1.5 with 96% sensitivi ty 94% specificity, and 96% positive and 94% negative predictive value. We conclude that quantitative transthoracic echocardiography can be used to sc reen for a significant shunt in patients with atrial septal defects.