Left-sided 3D totally endoscopic mitral valve repair guided by left atrial appendage orientation in situs inversus totalis with mirror-image dextrocardia: a case report

Situs inversus totalis with mirror-image dextrocardia is a rare anatomical condition that creates specific challenges for minimally invasive mitral valve surgery. In totally endoscopic procedures, the reversed cardiac orientation may affect thoracic access, peripheral cannulation, left atrial exposure and accurate identification of mitral valve segments. We report a case of left-sided three-dimensional totally endoscopic mitral valve repair in this setting, with emphasis on operative planning and intraoperative segment orientation. A 39-year-old woman presented with progressive exertional dyspnea and New York Heart Association class II to III symptoms. Echocardiography showed severe mitral regurgitation caused by posterior leaflet prolapse involving P2 and extending toward P3. Computed tomography angiography confirmed situs inversus totalis, mirror-image dextrocardia, a right-sided aortic arch, bilateral superior vena cavae and an uninterrupted inferior vena cava. A left-sided three-dimensional totally endoscopic approach was used with peripheral cardiopulmonary bypass through the left femoral vessels and supplemental left internal jugular venous drainage. Intraoperative segment orientation was deliberately re-established using the left atrial appendage as a fixed landmark to identify the A1/P1 side and distinguish it from A3/P3. Valve repair consisted of neochordal implantation to the prolapsing posterior leaflet and ring annuloplasty. Intraoperative transesophageal echocardiography, predischarge transthoracic echocardiography and 1-month follow-up transthoracic echocardiography showed no residual or recurrent mitral regurgitation, with preserved left ventricular systolic function at follow-up. This case illustrates that valve-preserving, totally endoscopic mitral repair can be feasible in situs inversus totalis with mirror-image dextrocardia when imaging, cannulation, access and segment orientation are planned as a single operative strategy. The main educational message is that, in this case, the left atrial appendage served as a practical anatomical reference for maintaining segmental orientation during mitral repair in mirror-image anatomy.