ASD with right to left shunt on colour Doppler echocardiography

Subcostal view on echocardiography showing atrial septal defect (ASD) with right to left shunt
Classically atrial septal defect (ASD) is best imaged from the subcostal view on echocardiography as the septum is perpendicular to the ultrasound beam in this view. The ASD is marked with stars in the left image panel. Right image panel shows the colour Doppler flow pattern across the ASD. Blue colour indicates that the flow is away from the transducer. In this case a downward flow across the ASD in this view is from right atrium to left atrium (right to left shunt). When right to left shunt across the atrial septum is noted in an infant during echocardiography, the first thing to look for is total anomalous pulmonary venous connection. When all the pulmonary veins are connected to the right atrium instead of the left, there is an obligatory right to left shunt across the ASD in order to sustain life. In an adult, right to left shunt across the ASD would mean severe pulmonary hypertension and reversal of the shunt. But transient right to left shunt across the ASD can occur even without severe pulmonary hypertension due to phasic fluctuation of atrial pressures with respiration and Valsalva maneuver.

Source: Cardiophile MD - December 18, 2015 Category: Cardiology Authors: Prof. Dr. Johnson Francis, MD, DM, FACC, FRCP Edin, FRCP London Tags: General Cardiology Source Type: blogs