Mitral regurgitation is when an incompetent mitral valve allows blood to leak back through during systolic contraction of the left ventricle.

• The second most common valve disease after aortic stenosis

Pathophysiology

• MR leads to a less efficient heart as less blood is pumped out to body - however it is common in otherwise healthy patients (not requiring Tx)
• As the degree of regurgitation becomes more severe, the body’s oxygen demands may exceed what the heart can supply and as a result, the myocardium can thicken over time. While this may be benign initially, patients may find themselves increasingly fatigued as a thicker myometrium becomes less efficient, and eventually go into irreversible heart failure.

Causes

Primary:

• degenerative mitral valve prolapse - deformed leaflets dont close properly
• infective endocarditis - when vegetations colonising the heart grow on the vbalve preventing it from closing properly
• Rheumatic fever - inflammation of valves causing regurgitation (uncommon in developed countries

Secondary:

• Post MI - damage to papillary muscles/chordae tendinae: no support to mitral valve

Risk factors:

• Female sex
• Lower body mass
• Age