The multifactorial etiology of mitral valve prolapse, a new entity of postinflammatory mitral valve prolapse

As etiologic factors for mitral valve prolapse, papillary muscle dysfunction due to coronary artery disease, hypertrophic obstructive cardiomyopathy, atrial septal defect and trauma have been reported. Connective tissue diseases such as Marfan's syndrome. Ehlers-Danlos syndrome or Turner's syndrome may also result in mitral valve prolapse. In the majority of patients with mitral valve prolapse, however, the etiology is unknown, in which case the condition is considered primary or idiopathic. We evaluated 33 consecutive surgically-excised mitral valves removed from patients with regurgitant prolapsing mitral valves and congestive heart failure. On microscopic examination, myxomatous degeneration was observed in 14 cases, postinflammatory changes, however, were seen in the other 19 cases and included diffuse vascularization with thick-walled vessels, round-cell infiltration and destruction of valve architecture. These valves showed a varying degree of doming and/or interchordal hooding as well as an increased surface area. Elongated chordae tendineae were seen in 37%, chordal rupture in 16% of the patients. Slightly fused chordae tendineae, minimal commissural fusion and/or fibrous thickening of cusps were also observed, findings which simulate closely rheumatic valvulitis. Patients with postinflammatory mitral valve prolapse were younger at the time of operation and at the onset of symptoms, had smaller surface areas of the anterior mitral leaflet and more marked leaflet thickening than patients with myxomatous mitral valve prolapse. The results of the study show that mitral valve prolapse in patients with severe mitral regurgitation can be attributed to postinflammatory changes; we suggest, therefore, the term "postinflammatory valve prolapse". Postinflammatory mitral valve prolapse may be due to manifest or subclinical rheumatic fever.(ABSTRACT TRUNCATED AT 250 WORDS)