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