The mitral valve prolapse syndrome. Spectrum and therapy

The medicalization of normal variants: the case of mitral valve prolapse

Mild mitral valve prolapse, hypoglycemia, irritable colon, and premenstrual syndrome are examples of anatomico-physiologic phenomena that largely overlap with normal. Such "overlap syndromes" become labeled disease entities by the medical community through a process called medicalization. This report uses mitral valve prolapse (MVP) to exemplify the effects of medicalization on patients, physicians, and society. Ascertainment bias and insufficient controlled clinical studies have led to the description of a clinical entity replete with false associations (e.g., mitral valve prolapse syndrome) and overly pessimistic prognostication (e.g., risk of sudden death or endocarditis), leading to clinical overreaction, overtreatment, and unnecessary induction of disability. Though some physical complications may be prevented by recognizing severe MVP, there is substantial risk of iatrogenic harm by attributing complex symptoms and illness behavior to mild MVP, which is probably a normal variant. A three-dimensional analysis of illness experience is presented that may be of use in conceptualizing the clinical approach to overlap syndromes such as mild MVP. Conservative criteria for the diagnosis of significant MVP have been developed at the National Institutes of Health. Treatment of patients with mild MVP must emphasize that it is a normal variant without serious consequences. Because the risks of overmedicalization are so substantial, the impact of diagnostic labels on individual patients and society must be analyzed continually.

Infective endocarditis: a challenging disease

Enhanced clinical awareness of infective endocarditis, along with improved microbiologic methodology and more aggressive surgical intervention, has favorably influenced the outcome of the disease. The evolving nature of infective endocarditis over the past decade is described, as are the changing epidemiologic factors, microbiologic techniques, and echocardiographic contributions in the clinical management of patients with infective endocarditis.

Mitral valve prolapse. Recognizing and treating its manifestations and complications

Mitral valve prolapse is a common, multisystem syndrome for which the myxomatous mitral valve provides an anatomic hallmark. Symptoms are often unrelated to the valvular abnormality and rarely hazardous and should generally be handled conservatively. In contrast, cardiovascular complications are not rare and should be anticipated and treated aggressively.

Mitral valve prolapse. Cross sectional and provocative M-mode echocardiography

False-negative supine M-mode echocardiograms occur in some patients with proved mitral valve prolapse. To investigate further, we performed M-mode echocardiography (MME) during standing and after the inhalation of amyl nitrite in 17 patients (group 1) selected for auscultatory evidence of mitral valve prolapse (MVP) but negative supine MME. To validate the standing MME technique, eight patients with classic auscultatory MVP with positive supine MME for MVP (group 2) and 15 control subjects (group 3) were studied. Supine cross-sectional echocardiography (CSE) was compared to MME in all three groups. Standing MME elicited echocardiographic evidence of MVP in 14/17 (82 percent) of group 1--auscultatory evidence of MVP but negative supine MME; CSE demonstrated MVP in 8/13 (62 per cent) of the same patients. There was no clear advantage of the CSE long axis view over the CSE apical four chamber view in the diagnosis of MVP in these selected subjects; however, the two views were complementary. Amyl nitrite was ineffective in eliciting echocardiographic evidence of MVP.

Mitral valve prolapse and cerebral ischemic events. A comparison between a neurology population with stroke and a cardiology population with mitral valve prolapse observed for five years

Two populations of patients with mitral valve prolapse were analyzed to identify factors predisposing to the development of cerebral emboli. Of 760 patients followed for up to five years by our cardiologists with echocardiographically demonstrated mitral valve prolapse (MVP), only one, aged 82 years, has had a stroke. In contrast, of 43 patients admitted to our neurology service with a cerebral embolus and no evidence of carotid or other cardiac lesion and in whom echocardiography was performed, MVP was present in 9. No contributing etiologic mechanisms were uncovered to account for the disparity between the cardiology and neurology populations. However, with the apparent increased incidence of MVP in young patients with cerebral ischemia, both groups require longitudinal follow-up to understand better the factors that predispose a small percentage of patients with mitral valve prolapse to the development of cerebral ischemia.