Which of the following features on X-ray chest can differentiate an Atrial septal Defect (ADH) from a Ventricular Septal Defect (VSD) ?

Usually left atrium does not enlarge in size in ASD unless associated with other anomalies like mitral regurgitation, but in large left to right shunt VSD there will be left atrial enlargement. DIFFERENTIATING AN ASD FROM A VSD USING A CHEST X-RAY Left atrium is not dilated in a case of atrial septal defect (ASD). It is dilated in patients with ventricular septal defect. (VSD). Pulmonary plethora is present in both ASD and VSD. Pulmonary aery is dilated in both. Size of the aoa is normal in both. Ref : Ghai essential of pediatrics ,eighth edition, P.no:413