[Right heart failure in a patient with unexplained tricuspid regurgitation and a rare congenital heart disease].

We report the case of a 63-year-old woman admitted to the intensive care unit because of acute decompensated right heart failure. Transthoracic and transesophageal echocardiography revealed severe right ventricular dysfunction with severe tricuspid regurgitation of unknown origin and a large membrane running from the inferior vena cava to the interatrial septum with significant diastolic transmembrane gradient, consistent with the diagnosis of cor triatriatum dexter. The clinical interest of our findings relies on the coexistence of multiple diseases, which actually contributed in a different but synergistic manner to right heart failure.