Floppy mitral valve/mitral valve prolapse syndrome: Beta-adrenergic receptor polymorphism may contribute to the pathogenesis of symptoms

AbstractBackgroundCertain patients with floppy mitral valve (FMV)/mitral valve prolapse (MVP) may have symptoms that cannot be explained on the severity of mitral valvular regurgitation (MVR) alone; hypersensitivity to adrenergic stimulation has been suggested in this group defined as the FMV/MVP syndrome.MethodsNinety-eight patients (75 men, 23 women) with mitral valve surgery for FMV/MVP were studied. Of those 41 (42%) had symptoms consistent with FMV/MVP syndrome [29 men (39%), 12 women (52%)]; median age of symptom onset was 30 years (range 10–63 years) and median duration of symptoms prior to valve surgery was 16 years (range 3–50 years). Ninety-nine individuals (70 men, 29 women) without clinical evidence of any disease were used as controls. Genotyping of β1 and β2 adrenergic receptors was performed.Resultsβ-Adrenergic receptor genotypes (β1 and β2) were similar between control and overall FMV/MVP patients. Subgroup analysis of patients, however, demonstrated that the genotype C/C at position 1165 resulting in 389 Arg/Arg of the β1 receptor was more frequent in women compared to those without FMV/MVP syndrome and to normal control women (p<0.025). This polymorphism may be related to hypersensitivity to adrenergic stimulation as reported previously in these patients.ConclusionThis study shows a large proportion of patients with FMV/MVP, predominantly women, had symptoms consistent with the FMV/MVP syndrome for many years prior to the development of significant MVR, and thus symptoms cannot be attributed to the severity of MVR alone. Further, women with FMV/MVP syndrome, symptoms at least partially may be related to β1-adrenergic receptor polymorphism, which has been shown previously to be associated with a hyperresponse to adrenergic stimulation

Floppy Mitral Valve (FMV) – Mitral Valve Prolapse (MVP) – Mitral Valvular Regurgitation and FMV/MVP Syndrome

Mitral valve prolapse (MVP) results from the systolic movement of a portion(s) or segment(s) of the mitral valve leaflet(s) into the left atrium during left ventricular (LV) systole. It should be emphasised that MVP alone, as defined by imaging techniques, may comprise a non-specific finding because it also depends on the LV volume, myocardial contractility and other LV hemodynamics. Thus, a floppy mitral valve (FMV) should be the basis for the diagnosis of MVP. Two types of symptoms may be defined in these patients. In one group, symptoms are directly related to progressive mitral regurgitation and its complications. In the other group, symptoms cannot be explained only by the degree of mitral regurgitation alone; neuroendocrine dysfunction has been implicated for the explanation of symptoms in this group of patients that today is referred as the FMV/MVP syndrome. When significant mitral regurgitation is present in a patient with FMV/MVP, surgical intervention is recommended. In patients with a prohibitive risk for surgery, transcatheter mitral valve repair using a mitraclip device may be considered. Furthermore, transcatheter mitral valve replacement may represent an option in the near future as clinical trials are underway. In this brief review, the current concepts related to FMV/MVP and FMV/MVP syndrome will be discussed