Papillary muscle stump mimicking a left ventricular mass after mitral valve replacement with partial chordal preservation

Background: Maintaining continuity between the mitral valve and the subvalvular apparatus during mitral valve replacement (MVR) maximizes the left ventricular (LV) function and increases the survival rate. However, MVR potentially cause rupture of the papillary muscles, systemic embolization, or dehiscence of the mitral annulus from the transposed position. Objective: We presented a case with severe rheumatic mitral valve disease treated with MVR and partial preservation of the posterior and anterior chordae tendineae. Methods: Retrospectively review of medical records. Results: Transthoracic echocardiography performed two weeks after surgery revealed a floating mass in the posterior inferior aspect of the left atrium and a lobulated mass joining the tip of the posterior papillary muscle in the left ventricle. Perioperative examination confirmed a large thrombus in the left atrium and the stump of the preserved posterior papillary muscle of the mitral valve. Conclusion: Thus, the papillary muscle could present itself as an abnormal mass on echocardiography, resulting in misdiagnosing.