Typically, right heart failure (RHF) may occur following left heart failure (LHF) in chronic volume overload states such as chronic severe mitral regurgitation (MR) through chronically elevated pulmonary pressures. In Lutembacher syndrome (LS), the direct shunting through a secundum type atrial septal defect (ASD) results in congestive heart failure in the setting of severe mitral stenosis (MS) with or without elevated pulmonary arterial or venous pressures. We report a rare case of severe isolated RHF and bi-atrial enlargement resulting from the direct shunting through a secundum type ASD in the presence of a severe eccentric primary MR. There are no significant cases documented like this after a thorough search using PubMed, Medline, and Google Scholar. A review of the literature suggests that LS is also caused by a combination of mitral regurgitation and a secundum-type atrial septal defect without mitral stenosis, though rarely. Because this is a primary MR, we feel it is a case of LS with MR, ruling out a combination of secondary MR and secundum-type atrial septal defect.