Since the successful clinical introduction of extracorporeal circulation1 in 1953, the majority of operations performed with the aid of this technique have been for congenital heart disease. Open heart surgery for acquired heart disease has developed more slowly, and mitral insufficiency, among other acquired valvular defects, only recently has come under direct surgical attack. Until relatively recently, pure mitral insufficiency was considered a rarity and of debatable significance with regard to cardiac function. We now know that mitral insufficiency, although less common than mitral stenosis as a predominant lesion, is a recognizable entity and can be a progressive disabling disease.
The anatomic factors which may underlie incompetence of the mitral valve are many and complex. They have been reviewed in some detail by Edwards and Burchell2 and need not be repeated here. It is of importance, however, to recognize that "mitral insufficiency begets mitral insufficiency." That is to