Fibromuscular dysplasia of small coronary arteries and fibrosis in the basilar ventricular septum in mitral valve prolapse, , ,

The mechanism of sudden cardiac death in patients with mitral valve prolapse is poorly understood. Twenty-four hearts from patients with mitral valve prolapse who suddenly died (mean age 34 ± 8 years) and 16 trauma control hearts (mean age 30 ± 7 years) were histologically studied. Dysplasia of the atrioventricular nodal artery was present in 18 of 24 hearts with mitral valve prolapse and four of 16 controls hearts ( p = 0.003). The degree of luminal narrowing, as morphometrically measured, was significantly greater in hearts with mitral valve prolapse ( p = 0.003). The degree of fibrosis in the base of the ventricular septum, as calculated by computerized morphometry, was greater in hearts with mitral valve prolapse ( p = 0.0002) and independent of age, sex, and heart weight ( p = 0.005). We conclude that arterial dysplasia in mitral valve prolapse may contribute to sudden cardiac death mediated by ventricular fibrosis. (AM Heart J 1997;134:282-91.)