Study of four personal cases and of twelve cases reported in the literature makes it possible to describe the characteristics of coronary embolism in mitral stenosis, a rare complication but indicating the presence of a left intra-atrial thrombosis: -- variable clinical picture, dominated by a syndrome combining simultaneously a picture of myocardial infarction and of peripheral arterial emboli of other localizations; -- diagnosis to be discussed within the framework of coronary syndromes in mitral heart disease: embolism requiring to be distinguished from coronary atherosclerosis combined with mitral stenosis, more rarely a functional coronary insufficiency; -- severe course and prognosis: besides the possibility of rapidly lethal cases, coronary embolism seems liable to result in weakening and diminishing of the adaptation possibilities of the left ventricle, responsible for attacks of heart failure after mitral valvulotomy.