Pure mitral regurgitation. Etiology, pathology and clinical patterns.

The varied etiology of pure mitral regurgitation is demonstrated in this clinicopathological study, comprising 59 surgically treated cases with this condition. One third of the cases was of rheumatic origin, one fifth had ischemic heart disease, another fifth floppy valves and one eighth an isolated rupture of the chordae with necrosis of the chord matrix. To our knowledge the histopathological findings in the last group have not been described before. Congenital mitral regurgitation, bacterial endocarditis and cardiomyopathy were rare causes of mitral regurgitation. Differences between the groups were observed in the sex ratio, duration of history, auscultatory findings ECG signs, compliance of the left ventricle and in the morphological findings.