[Basedow's disease and mitral valve prolapse].

The prevalence of mitral valve prolapse was investigated in 60 patients with Graves' disease (42 with ophthalmopathy) and in 20 patients with toxic nodular goitre. 2410 patients from the echocardiography laboratory served as controls. Standard M-mode, Doppler and two-dimensional echocardiography were performed. Mitral valve prolapse was defined as a systolic buckling greater than or equal to 3 mm. In patients with thyroid disease HLA antigens were determined. Patients with Graves' disease showed a significantly higher incidence of mitral valve prolapse (36/60, 60%) compared to the group with toxic nodular goitre (2/20, 10%) and to controls (238/2410, 9,9%) (P less than 0.0001). 16 of 36 patients had a prolapse of the anterior, in 3 of 36 the posterior leaflet was involved and 17 of 36 had both. Mean systolic buckling was 4.3 +/- 1.5 mm. 28 of 42 patients with ophthalmopathy (67%) showed a mitral valve prolapse. 20 of 60 patients (33.3%) with Graves' disease but none in the goitre group showed a thickened myxomatous valve (P less than 0.001). Thyroid function did not influence the incidence and intensity of the prolapse. The HLA phenotypes B8 were seen in 22 of 36 and DR3 in 24 of 36 patients with mitral valve prolapse. Since thyroid function was comparable in both groups an involvement of the mitral valve in an autoimmune process affecting several organs can be considered probable.