Non-rheumatic mitral incompetence and papillary muscle dysfunction.

Non-rheumatic mitral incompetence may be caused by a variety of conditions affecting the relationships between the papillary muscles, chordae tendineae and mitral valve cusps. Among the commonest of these conditions are ventricular dilatation, ischaemia, congenital and familial abnormalities, senile atrophy of the muscles and spontaneous rupture. There is a very wide range of severity of the resultant clinical syndromes. Some patients are asymptomatic, others are moderately or severely incapacitated, while the severest cases may have acute pulmonary oedema which may be rapidly fatal. The diagnosis is strongly suggested by a late systolic murmur which may be initiated by a mid-systolic click while in others there is the unusual combination of an ejection-type systolic murmur with a quick-rising pulse. The diagnosis can be conclusively established by cineangiography and severe cases can be greatly helped by replacement of the mitral valve with a prosthesis.