| Abstract: | Although echocardiography has been useful in diagnosing significant left-to-right shunts at the atrial level, few studies using this technique to quantitate shunt size have been performed. Echocardiograms and hemodynamic data from 28 patients, ages 15 to 58 (mean : 30 years) were reviewed. Twenty patients had isolated atrial septal defects (ASD), 6 patients has associated partial pulmonary venous returns (PPVR) and 2 patients had isolated PPVR. Echocardiograms in the supine position were performed within 24 hours preceding cardiac catheterization. The presence or absence of paradoxical septal motion was noted and right ventricular diameter index (RVDE : right ventricular diameter/body surface area) was calculated. Hemodynamic parameters studied included pulmonary to systemic flow ratio (Qp/Qs) determined by oxymetry, right ventricular pressure (RVP) and pulmonary resistance (PR). One patient with a Qp/Qs of 1.3 had normal septal motion. Type A paradoxical septal motion was noted in 22 cases, type B in 5 cases. For these 27 patients, the average RVDI was 2.42 (range 1.45 to 3.7), Qp/Qs ranged from 1.5 to 5 (mean : 2.45), RVP from 23 to 71 mmHg (mean : 39) and PR from 0.6 to 4 units (mean : 1.79). A very strons correlation between RVDI and Qp/Qs was observed from equation Qp/Qs : 1.19 RVDI-0.43 with a standard error of 0.4. This relationship was not altered by either RVP or PR values, which also had no apparent correlation with RVDI. This study indicates that echocardiographic measurement of RVDI is a reliable and non-invasive method of evaluating the size of left to right shunts at the atrial level. |
