Water bottle hea is seen in -

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