[Measurement by Doppler echocardiography of the ratio of pulmonary/systemic flow rates in atrial septal defects. Apropos of 15 cases].

Fifteen patients with an ostium secundum type atrial septal defect, aged between 5 and 68 (mean = 31) underwent Doppler-echocardiographic evaluation of the ratio of pulmonary and systemic flow rates. Systemic flow was evaluated at the aortic orifice, as well as at the mitral ring and at the extremities of the mitral cusps, based upon the measurement of valve diameters by 2D or TM echocardiography, pulsed Doppler velocity curve and hear rate. Pulmonary flow was measured by the same technique at the site of insertion of the pulmonary cusps. The values obtained were compared with cardiac catheterisation findings, the reference method being an oxymetric measurement of the shunt ratio. Feasibility of the Doppler investigation was 100 per cent. Correlation between the two techniques was r = 0.85 when the Doppler measurement was at the aorta, r = 0.81 for the mitral ring and r = 0.71 at the extremity of the mitral cusps. Doppler-echocardiography thus appears to be a reliable and reproducible method for the evaluation of left-right shunts, confirming data from the literature.