[Evaluation of the left-to-right shunt in interatrial septal defects (ostium secundum) using Doppler echocardiography. Apropos of 12 cases].

In 12 patients with inter-atrial communication (ostium secundum) (IAC-OS), and ages ranging between 8 and 63 years (mean = 21 years), the ratio between pulmonary and systemic flow (QP/QS) was evaluated with the use of Doppler ultrasonography and compared with the QP/QS obtained by oxymetric measurement during catheterization. The pulmonary or systemic flow is evaluated from the diameter of the opening (d) and the velocity curve (ITV) recorded by pulsated Doppler in the aorta and the pulmonary artery; Q = d2/4 x ITV x heart rate both examinations (sonogram and catheterization) are performed in less than 24 hours. The results show a good correlation between both methods (R = 0.948) (Y = 0.756 X + 0.692). There is no significant variation between intra- or inter-observer. The findings of this study are comparable to those already published; the main difficulty in evaluating of the QP/QS by Doppler sonography are related to the measurement of the pulmonary diameter and there recording of good velocity curves. The QP/QS evaluated by Doppler sonography from a simplified calculation method advocated by Oloez et al. (QP/QS = d2 Ap x V max Ap/d2 Ao x V max Ao were compared, in retrospect, to the data provided by catheterization. The correlation is also satisfactory (R = 0.893). The Doppler ultrasonography is therefore a reliable and reproducible method in as far as the measurement of QP/QS in young or adults subjects affected with IAC OS.