Disproportionate right heart enlargement in a patient with small atrial septal defect: hidden abnormal pulmonary venous return

Abstract

A 39-year-old male patient admitted due to palpitations. His past medical history was unremarkable. A cardiovascular examination and surface electrocardiography results were normal. Transthoracic echocardiography revealed normal left ventricular function with moderate right heart chamber dilation, mild tricuspid regurgitation, a small secundum atrial septal defect (ASD), and systolic pulmonary artery pressure of 30 mm Hg.