Missed case of sinus venosus atrial septal defect post coronary artery bypass grafting

We report a case of a 41-year-old Indian man who initially underwent an emergency coronary artery bypass grafting surgery (CABG) after presenting with an anterolateral myocardial infarction.Post-operatively he developed progressively worsening symptoms of right heart failure with increasing abdominal distension and lower limb swelling. Clinically, the patient was in NYHA class 4 heart failure.He was admitted multiple times for the treatment of his heart failure, which was recalcitrant to diuretic therapy.He subsequently underwent an MRI scan, which revealed near transmural myocardial infarction involving mainly the left side of the heart. The right atrium and ventricle were grossly dilated, with moderate to severe right ventricular systolic dysfunction. A sinus venosus atrial septal defect with right-sided partial anomalous pulmonary venous drainange (PAPVD) was noted. He subsequently underwent surgery to repair the sinus venosus atrial septal defect (ASD) as well as re-route the PAPVD to the left atrium (LA). He was discharged on post-operative day 19 with oral diuretics.On follow-up at 1 month, the patient's symptoms had resolved and his clinical status corresponded to NYHA class 1-2.