Table 1: The aetiology of chronic and acute MR
Chronic MR Acute MR
  • Rheumatic heart disease
  • LV dilatation secondary to ischaemic heart disease or cardiomyopathy
  • Myxomatous degeneration
  • Mitral valve prolapse
  • Ruptured chordae tendinae or partial or complete papillary muscle rupture (e.g. due to acute myocardial infarction, trauma or infective endocarditis)

Mitral regurgitation is back flow of blood from the left ventricle into the left atrium during systole. This causes volume overloading of the left atrium and an increased workload for the ventricle to maintain the ejection fraction. As with aortic valve incompetence, mitral regurgitation may be acute or chronic.

Mitral Valve regurgitation occurs in about 2% of the population. Acute MR is a cardiovascular emergency. The aetiology of chronic and acute MR is shown in Table 1.