Noninvasive pulsed Doppler echocardiographic detection of the direction of shunt flow in patients with atrial septal defect: usefulness of the right parasternal approach.

Abstract

Noninvasive pulsed Doppler echocardiography combined with two-dimensional echocardiography by the right parasternal approach was performed to detect the shunt flow through the defect in 31 patients with suspected secundum atrial septal defect (ASD). A defect of the interatrial septum was seen on the two-dimensional echocardiograms of 30 of 31 patients. In all the 30 patients, Doppler signals of shunt flow could be recorded by placing the sample volume in the center of the defect on the two-dimensional echocardiogram. Neither a defect nor Doppler signal indicating shunt flow were demonstrated in any of 15 normal control subjects. Cardiac catheterization indicated significant shunt flow in all the 31 patients with suspected ASD. Doppler signals obtained from the center of the defect showed left-to-right and/or right-to-left shunt flow patterns. The direction of the shunt flow was mainly left to right, with its peak in late systole and atrial systole in 28 of 30 patients; mainly right-to-left flow was present in the remaining two patients, who had Eisenmenger's syndrome. The direction of flow as predicted by the Doppler signal was confirmed by the coincidence of direction of flow as seen on the contrast two-dimensional echocardiogram. In 22 patients for whom the measurement of the pulmonary-to-systemic flow ratio by oximetry was believed to be reasonably accurate, the ratio was fairly well correlated with Doppler-determined left-to-right shunt flow velocity (r = .71, SEE = 6.7 cm/sec). In 13 patients with ASD who underwent surgical repair of the defect, postoperatively the defect on the two-dimensional echocardiogram and the Doppler signals indicating shunt flow disappeared. In conclusion, noninvasive pulsed Doppler echocardiography by the right parasternal approach is useful in the assessment of the direction of shunt flow in patients with ASD.

An endocardial pathway involving Tbx5, Gata4, and Nos3 required for atrial septum formation

“…2C) that could be caused by a reversal of the left-to-right shunting. This has been observed in humans with right ventricle failure or stiffness in which the left-to-right shunting decreases and right-to-left shunting may occur and increase the flow in the left atrium, causing the increase in MV flow (31,32). Other causes explaining the increased MV pressure gradient were eliminated.…”

Echocardiographic Detection of Atrial Septal Defects: The Forgotten View

“…Minagoe and colleagues demonstrated that the right parasternal view provided a useful window to assess the direction of flow across an atrial septal defect many years ago, 6 and later that this approach provided visualization of the deviated interatrial septum in patients with mitral stenosis and giant left atria. 7 In this second study, the right parasternal view was also used to assess flow velocity within the IVC.…”

Bidirectional flow in congenital ventricular septal defect: A doppler echocardiographic study

“…Recently, in a study similar to OUTS, pulsed Doppler echo combined with 2D echo was reported to be a useful tool for detecting bidirectional flow patterns in patients with atrial septal defect (Minagoe et al, 1985).…”