Case Presentation: 75 year old with non-alcoholic cirrhosis, heart failure preserved ejection fraction (HFpEF) and recurrent abdominal abscesses presented with platypnea orthodeoxia syndrome (POS) following diuresis. His oxygen saturation was 100% when lying flat and 78-80% when upright. Trans-esophageal echocardiogram confirmed a sinus venosus defect (SVD) with partial anomalous pulmonary venous return (PAPVR) of right [...]