Cardiac herniation through a pericardial defect after minimally invasive mitral valve surgery

Minimally invasive mitral valve surgery has been increasingly performed because of its presumed advantages over traditional surgery performed through median sternotomy. Cardiac herniation is an extremely rare complication initially reported by Bettman and Tannenbaum in 1948. It is usually reported after blunt chest trauma or pneumonectomy, but can potentially occur after any minimally invasive surgery involving a pericardial incision. In this case report, we present 2 cases of cardiac herniation occurring after minimally invasive mitral valve surgery; the 2 cases had different surgical exposures and clinical presentations. Early diagnosis is crucial for a timely lifesaving definitive management.