AKT · Cardiovascular/Valves & endocardium

Mitral regurgitation

Incompetent mitral valve → systolic backflow into the left atrium

Overview

Systolic leakage of blood back into the left atrium. Primary MR is a valve problem (myxomatous prolapse, rheumatic, endocarditis, ruptured chordae tendineae, papillary muscle rupture post-MI); secondary (functional) MR results from LV dilatation. Chronic MR causes a pansystolic murmur radiating to the axilla and gradual LA/LV dilatation; acute MR (chordae/papillary rupture) causes sudden pulmonary oedema.

Recognise

Pansystolic murmur at the apex radiating to the axilla; soft S1; displaced hyperdynamic apex; may have a 3rd heart sound
Chronic: exertional dyspnoea, fatigue, AF; acute (ruptured chordae tendineae or post-MI papillary rupture): sudden severe pulmonary oedema and shock
Mitral valve prolapse: mid-systolic click + late systolic murmur
Pressure-trace clue: MR generates a large systolic V-WAVE in the LA (and PCWP) tracing — the regurgitant jet fills the atrium during ventricular systole; a tall LA v-wave on aorta/LV/LA tracings points to (acute) MR rather than aortic stenosis

Red flags

Acute severe MR from papillary muscle rupture (days after an inferior MI) → cardiogenic shock → emergency surgery
New MR + fever → endocarditis

Differentials & how to tell them apart

Aortic stenosisejection systolic, radiates to carotids, slow-rising pulse

Tricuspid regurgitationleft lower sternal edge, louder on inspiration, giant V waves in JVP

Ventricular septal defectharsh pansystolic at the left sternal edge with a thrill

Investigations

Echo (mechanism, severity, LV size/function, LA size — the key test); ECG (AF, LVH, P mitrale); CXR; coronary angiography before surgery; blood cultures if endocarditis suspected.

Management

HF therapy for symptoms/secondary MR; mitral repair (preferred) or replacement for severe primary MR

1Confirm mechanism and severity on echo; assess LV function and LA size. Treat symptoms/secondary MR with heart-failure therapy and anticoagulate for AF.Gate: Acute severe MR (papillary muscle rupture post-MI) → emergency surgery — it presents as sudden pulmonary oedema/shock.
2Severe primary MR with symptoms or LV dysfunction → mitral valve REPAIR (preferred over replacement) or TEER in selected high-risk patients.

Heart-failure therapy (ACEi/ARB, beta-blocker, diuretic) for symptoms / secondary MR — manage LV dysfunction; secondary MR improves with HF treatment

Mitral valve repair (preferred) or replacement — for severe primary MR with symptoms or LV dysfunction; repair preserves function

Transcatheter edge-to-edge repair (TEER) — for selected high-risk/secondary MR

Anticoagulation for AF — common in chronic MR

Key points

Pansystolic murmur at the apex radiating to the axilla = mitral regurgitation. Chronic → HF therapy and repair when severe/symptomatic. Sudden pulmonary oedema days after an inferior MI = papillary muscle rupture (acute MR) → emergency surgery.

Monitor & prognosis

Serial echo (LV/LA, EF), symptom status, AF management.

Good with timely repair; acute MR is an emergency.

Source: NICE NG208; ESC valve guideline