Crab view is the view of the pulmonary veins by colour Doppler using a low velocity to capture pulmonary venous flow, as it enters the left atrium (in normal configuration). Beware that pulmonary veins may partially or totally be draining in another structure than the left atrium (TAPVR or PAPVR). We attempt to locate the ostium. A PW Doppler should be done on every vein at its opening in the left atrium. The biphasic or triphasic pattern should be identified. Some flow reversal may occur during the atrial contraction. A prolonged atrial reversal duration may be associated with underlying LV diastolic dysfunction (poor compliance). This sign of diastolic dysfunction is often reported in the pediatric or adult literature. However, it has not been systematically reported in neonatal conditions with LV diastolic dysfunction (such as in the conditions with LV hypertrophy).