<prompt> Water bottle hea is seen in -PDAChronic emphysemaPericardial effusionConstrictive pericarditis  <response>: It refers to the shape of the cardiac silhouette on erect front chest xrays in paients who has a large pericardial effusion. there can be globular enlargement of the cardiac shadow giving a water bottle configuration lateral CXR may show a veical opaque line pericardial fluid separating a veical lucent line directly behind the sternum pericardial fat anteriorly from a similar lucent veical lucent line epicardial fat posteriorly; this is known as the Oreo cookie sign 5 