Spontaneous coronary artery dissection is a rare condition usually encountered in young women without risk factors for atherosclerotic disease but with tortuous coronary artery or contemporary presence of fibromuscular dysplasia. Sometimes spontaneous coronary dissection occurs in patients with atherosclerotic disease, although without significant epicardial coronary artery stenosis. We report a case of a patient who underwent minimally invasive mitral valve repair, whose initially uneventful postoperative course was complicated by spontaneous coronary artery dissection of the left main causing a life threatening condition. A subsequent emergency sternotomy was required to perform a coronary artery bypass.