A registry is installed to collect (pre-, intra- and postoperative) data on patients undergoing mitral valve surgery at the Department for Cardiac Surgery of Universitätsspital Basel/ Switzerland since 2009. Retrospective data (since 2009) as well as prospective data are included in this ongoing registry to analyse the development of mitral valve surgery at the Department of Cardiac Surgery University Hospital of Basel/ Switzerland.

Inclusion Criteria:

- patients undergoing mitral valve surgery at the Department for Cardiac Surgery of Universitätsspital Basel/ Switzerland since 2009

Exclusion Criteria:

- patients refusing consent for data use

patients undergoing mitral valve surgery at the Department for Cardiac Surgery of Universitätsspital Basel/ Switzerland since 2009