Mitral Valve Prolapse

Basics

Description

  • Bulging of 1 or both of the mitral valve leaflets into the left atrium during systole
  • Occurs when the leaflet edges of the mitral valve do not coapt
  • Commonly due to abnormal stretching of 1 of the mitral valve leaflets during systole:
    • Myxomatous proliferation of the spongiosa layer within the valve causing focal interruption of the fibrosa layer
    • Excessive stretching of the chordae tendineae, leading to traction on papillary muscles
  • Theoretical explanations for associated chest pain:
    • Focal ischemia from coronary microembolism due to platelet aggregates and fibrin deposits in the angles between the leaflets
    • Coronary artery spasm
  • Mitral regurgitation (MR) may occur in some patients
  • Age of onset is 10–16 yr
  • Female > male (3:1)
  • Typically benign in young women, whereas men >50 yr tend to have serious sequelae and more often develop severe regurgitation requiring surgical intervention
  • Can be identified by ECG in 2–4% of the general population and in 7% of autopsies
  • A variety of neuroendocrine and autonomic disturbances occur in some patients
  • Genetics:
    • Strong hereditary component
    • Sometimes transmitted as an autosomal dominant trait with varying penetrance

Etiology

  • Marfan syndrome
  • Relapsing polychondritis
  • Ehlers–Danlos syndrome (i.e., types I, II, IV)
  • Osteogenesis imperfecta
  • Pseudoxanthoma elasticum
  • Stickler syndrome
  • Systemic lupus erythematosus
  • Polyarteritis nodosa
  • Polycystic kidney disease
  • von Willebrand syndrome
  • Duchenne muscular dystrophy

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