💡 Key Point: Mitral regurgitation (MR) = backward flow of blood from LV → LA during systole.
This leads to LA + LV volume overload, pulmonary congestion, AF, and eventual HF if untreated.
📖 About
- Definition: Retrograde systolic flow from LV → LA due to incomplete valve closure.
- Acute MR: 🚨 Sudden, no time for LA adaptation → pulmonary oedema + acute HF.
- Chronic MR: 🕰️ Gradual; LA dilates & compensates → later LV failure.
🧬 Pathophysiology
- Volume overload: Regurgitant jet ↑ LA pressure & volume → LA dilatation, eccentric LV hypertrophy.
- Acute MR: Sudden rise in LA pressure → pulmonary oedema, cardiogenic shock.
- Chronic MR: Initially well-tolerated → progressive LV dysfunction, HF, AF.
🔎 Causes
- 🎈 Mitral Valve Prolapse (MVP): Most common in developed world.
- 🌍 Rheumatic Heart Disease: Post-strep scarring & fusion (still common globally).
- ❤️ Ischaemic Heart Disease: Papillary muscle rupture or dysfunction post-MI.
- 🦠 Infective Endocarditis: Leaflet/chordal destruction → acute/chronic MR.
- ⚙️ Degenerative Valve Disease: Annular dilatation, calcification.
- 💔 Cardiomyopathy: Dilated/HCM distorts valve apparatus.
- 👶 Congenital: Cleft/parachute valve anomalies.
- 🧬 Connective Tissue: Marfan, Ehlers-Danlos, OI.
- 🩸 Trauma: Papillary/chordal rupture after chest injury.
🩺 Clinical Features
- Symptoms: Palpitations (AF), exertional dyspnoea, fatigue, orthopnoea/PND if severe.
- Signs:
- 🎶 Pansystolic murmur @ apex → axilla.
- 💓 S3 gallop (volume overload).
- Diffuse, displaced apex beat (LV dilatation).
- Soft S1, loud P2 (pulmonary HTN).
- ± Mid-diastolic rumble if large regurgitant volume.
🧪 Investigations
- Bloods: FBC, U&E; cultures if IE suspected.
- ECG: AF, LA enlargement (P mitrale), LVH.
- CXR: LA enlargement, pulmonary oedema, cardiomegaly.
- Echocardiography (TOE best detail): Valve anatomy, regurgitant jet, LA/LV size, pulmonary pressures.
- Cardiac cath: Confirms MR; PCWP shows giant V waves.
⚕️ Management
- 💊 Medical:
– Diuretics → relieve pulmonary congestion.
– ACEi/ARB → reduce afterload.
– Rate control in AF (β-blockers, digoxin, Ca²⁺ blockers).
– Anticoagulation in AF (per CHA₂DS₂-VASc).
- 🔧 Surgical:
– Valve repair preferred (better survival, LV preservation).
– Valve replacement if not repairable (mechanical vs bioprosthetic).
- 🩹 Percutaneous:
– MitraClip for high-risk surgical patients.
– TMVR emerging option.
- ⚡ AF Management:
– Rate control, rhythm control, anticoagulation.
- 📊 Monitoring:
– Serial echo (LV function, LA size, pulmonary HTN).
– Clinical: symptoms, functional class.
- 🌱 Lifestyle:
– Moderate exercise.
– Low-salt diet.
– Stop smoking, manage HTN, lipids.
📚 Teaching Pearl
💡 Think MR = pansystolic apex murmur → axilla.
🧠 Acute MR = pulmonary oedema & shock.
🕰️ Chronic MR = AF + heart failure later.
Repair > Replace whenever feasible.
