Mitral Regurgitation

The pathological backflow of blood through the mitral valve into the left atrium.




  • Look for stigmata of endocarditis
  • Features of Marfans syndrome
  • bruising from warfarin for AF
  • Irregularly irregular pulse of AF
  • JVP: May be raised in RVF secondary to severe MR, can get giant CV waves due to functional TR from severe MR
  • Displaced apex and can have an apical systolic thrill.
  • Auscultation:
    • Soft S1 (closing of the mitral valve isn’t as loud due to MR)
    • High pitched pan systolic murmur that radiated to the apex and like all left sided valvular lesions is louder during expiration.
    • Widely split S2 if severe
    • S3 or S4 may be present


Severe Signs: Soft S1, S3 or S4, LV enlargement, mid-diastolic flow murmur, pulmonary congestion.


Signs of Mitral valve prolapse:


  • Normal S1
  • Later murmur, mid-late systole with opening click
  • Dynamic murmur: quieter on squatting and louder on standing




Acute: IE, rupture of chordae tendinae (IE, Rheumatic fever or more commonly post MI), Traumatic


Chronic: Rheumatic fever, Mitral valve prolapse (see below), functional (secondary to LV dilatation), Marfans syndrome, Ehlers Danlos syndrome, RA, SLE (libman-sachs endocarditis), cardiomyopathies and Mitral annular calcification


LV dilatation causes dilatation of MV annulus and this causes lateral displacement of the papillary muscles and thus functional MR.


Conditions associated with MVP: Polycystic kidneys, cardiomyopathy, Wolf-Parkinson-White syndrome, Patent ductus arteriosus, Marfans syndrome and muscular dystrophy




Bedside: ECG: AF, atrial hypertrophy (bifid P waves in II), Left axis deviation

Bloods: FBC &CRP & ESR & Blood cultures (IE), U&E (CKD in Polycystic kidneys) Rheumatoid Factor, ANA screen (SLE), 12 hr troponin if in setting of acute abdominal pain +/- ECG changes of MI.




MV repair or replacement is recommended in asymptomatic patients with LV EF 30-60% and LV end-systolic dimensions >40mm.

Patients with chronic MR who have new onset  AF if they have pulmonary pressures at rest in systole >50mmHg and a normal LVSF.

Surgery is rarely recommended in patients with severe LVSD.



Written by Dr Thomas Craven


Resources used to write this document are listed in the references section of this webpage