STRUCTURAL BASIS FOR MITRAL-VALVE DYSFUNCTION ASSOCIATED WITH OSTIUM-SECUNDUM ATRIAL SEPTAL-DEFECTS

Mitral valve (MV) specimens obtained at operation from 50 patients wit h ostium secundum atrial septal defect and associated MV dysfunction w ere studied macro- and microscopically to evaluate the structural lesi ons. The functional abnormalities in these patients were isolated mitr al stenosis, isolated mitral regurgitation, mitral valve prolapse or m itral stenosis with regurgitation. Post-inflammatory lesions were comm only found in those with mitral stenosis who had a past history of rhe umatic fever. Patients with mitral valve prolapse had either post-infl ammatory lesions or lesions attributable to haemodynamic stress but di fferent from the extensive lesions seen in floppy MV syndrome.