About This Page
This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
The Bottom Line
- AR = diastolic backflow through incompetent aortic valve → LV volume overload → eccentric hypertrophy → eventual dilatation and failure
- Causes: degenerative (commonest), bicuspid aortic valve, aortic root dilatation (Marfan, aortic dissection), infective endocarditis, rheumatic
- Early diastolic decrescendo murmur best heard at left sternal edge, sitting forward, in expiration
- Wide pulse pressure, collapsing (waterhammer) pulse, displaced hyperdynamic apex beat
- Surgery indicated when symptomatic or when LV dilates (LVESD >50 mm or LVEF <55%)
Overview
Aortic regurgitation (AR) occurs when the aortic valve fails to close completely during diastole, allowing blood to flow back from the aorta into the left ventricle. This creates a volume-loaded LV that compensates by eccentric hypertrophy and dilatation. Chronic AR may be well tolerated for years, but once the LV begins to fail, prognosis worsens significantly. Acute AR (e.g. from aortic dissection or endocarditis) is a surgical emergency as the non-compliant LV cannot accommodate the sudden volume load, leading to acute pulmonary oedema and cardiogenic shock.
Epidemiology
Moderate-to-severe AR affects approximately 0.5% of the population. The prevalence increases with age. In developed countries, degenerative disease and bicuspid aortic valve are the commonest causes. Rheumatic heart disease remains the leading cause in low-income countries. Other important causes include connective tissue disorders (Marfan syndrome, Ehlers-Danlos), aortic root dilatation, syphilitic aortitis (now rare), and inflammatory conditions (ankylosing spondylitis, reactive arthritis).
Clinical Features
Symptoms
Often asymptomatic for many years (chronic AR)
Exertional dyspnoea (earliest symptom)
Palpitations (awareness of forceful heartbeat, especially when lying on left side)
Angina (reduced diastolic coronary perfusion despite normal coronaries)
Orthopnoea and PND (LV failure)
Acute AR: sudden severe dyspnoea, cardiogenic shock
Signs
Early diastolic decrescendo murmur at left sternal edge — best heard sitting forward in held expiration
Collapsing (waterhammer) pulse — lift arm above heart to accentuate
Wide pulse pressure (e.g. 170/50 mmHg)
Displaced, hyperdynamic apex beat (volume-loaded LV)
Austin Flint murmur — low-pitched mid-diastolic rumble at apex (regurgitant jet impinging on anterior mitral leaflet)
Eponymous signs: de Musset (head bobbing), Quincke (nail-bed pulsation), Corrigan (visible carotid pulsation), Duroziez (femoral bruit with compression)
Investigations
First-line
Echocardiography (TTE)Assess severity of regurgitation (jet width, vena contracta, regurgitant volume), LV dimensions (LVEDD, LVESD), LVEF, aortic root size
ECGLVH with strain pattern. May show left axis deviation
Second-line
Chest X-rayCardiomegaly, aortic root dilatation, pulmonary congestion if decompensated
Cardiac MRIAccurate quantification of regurgitant volume/fraction; aortic root assessment
Specialist
CT aortogramIf aortic root pathology suspected (dissection, aneurysm, Marfan)
Cardiac catheterisationPre-operative coronary assessment; invasive haemodynamics if non-invasive data discordant
1
Surveillance (asymptomatic, normal LV)
- Serial echocardiography: mild every 3–5 years, moderate every 1–2 years, severe 6–12 monthly
- Educate patient on symptom recognition and when to seek review
2
Medical therapy
- No medical therapy delays need for surgery in chronic AR with normal LV function
- Vasodilators (ACEi/ARBs, nifedipine) may be used if hypertension present or if surgery declined/deferred
- Treat heart failure with standard therapy if decompensated while awaiting surgery
3
Surgical referral — aortic valve replacement/repair
- Symptomatic severe AR → surgical AVR
- Asymptomatic severe AR with LVEF <55% or LVESD >50 mm (or ESDI >24 mm/m²) → consider referral (NICE NG208)
- Aortic root dilatation ≥55 mm (or ≥50 mm in bicuspid valve / Marfan) → aortic root replacement
- Acute severe AR (dissection, endocarditis) → emergency surgery
Complications
- Heart failure: Progressive LV dilatation and systolic dysfunction — the most common complication
- Infective endocarditis: Regurgitant jets predispose to endocarditis
- Arrhythmias: AF, ventricular arrhythmias in dilated LV
- Aortic dissection: Especially with aortic root dilatation (Marfan syndrome)
- Sudden cardiac death: Rare, but occurs in severe AR with very dilated LV
UKMLA Exam Tips
- 1Early diastolic murmur at left sternal edge + collapsing pulse + wide pulse pressure = AR
- 2Acute AR (dissection, endocarditis) = surgical emergency — unlike chronic AR, the LV has no time to dilate and compensate
- 3The Austin Flint murmur mimics mitral stenosis — differentiate by noting there is no opening snap and the murmur increases in severity with worsening AR
- 4Marfan syndrome → think aortic root dilatation → AR + risk of dissection (tall, thin patient with long arms)
- 5In chronic AR, the apex beat is displaced AND hyperdynamic (volume-loaded) — contrast with AS where it is heaving but non-displaced (pressure-loaded)
practicetest your knowledge on aortic regurgitationApply what you've learnt with UKMLA-style questions from the iatroX Q-Bank — cardiovascular and beyond.
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