Accessory Mitral Valve Tissue in Mirror-Image Dextrocardia

A 20-year-old man was referred to us for further evaluation due to infective endocarditis. He had mirror-image dextrocardia with visceral situs inversus. He had a history of dyspnea on exertion (NYHA class II) of several years’ duration with no new onset symptoms. On physical examination, he had no peripheral stigmata of infective endocarditis. Laboratory examination showed a normal erythrocyte sedimentation rate with normal hemoglobin. Three separate sets of blood cultures obtained over a 24-hour period and cultures were negative in aerobic and anaerobic media. Transthoracic and transesophageal echocardiographic studies showed mirror-image dextrocardia with total situs inversus as well as accessory mitral valve tissue with chordal attachment to the posteromedial papillary muscle with no significant LVOT obstruction (Figs. 1,2) but resulting in mild to moderate aortic insufficiency (Fig.3). There was also aneurysmal dilation of the membranous part of the interventricular septum with a residual pouch and no residual ventricular septal defect according to computational fluid dynamics and contrast studies (Fig 4). There was no other concomitant abnormality. The patient was discharged in good physical condition