Aortic Regurgitation
Cardiology
Illness script · Cardiology
Aortic Regurgitation
Incompetent aortic valve allows diastolic backflow from aorta into LV, causing progressive volume overload and eccentric LV hypertrophy.
This illness script for Aortic Regurgitation covers predisposing factors, classic presentation, mechanism, workup, management, and the clinical pivots that separate it from look-alikes—written for USMLE Step 1 and clerkship reasoning.
01
Predisposing factors
- Bicuspid aortic valve — most common cause in young patients in the US
- Rheumatic heart disease — most common cause worldwide
- Aortic root dilation: Marfan syndrome, ankylosing spondylitis, tertiary syphilis
- Infective endocarditis — classic cause of acute severe AR
- Chronic hypertension and age-related aortic root dilation
02
Presentation
- Chronic AR: asymptomatic for decades, then exertional dyspnea and fatigue
- High-pitched, blowing early diastolic decrescendo murmur at left sternal border (3rd ICS)
- Best heard leaning forward in full expiration
- Wide pulse pressure (e.g., 160/60) with bounding water-hammer (Corrigan) pulse
- Austin Flint murmur: mid-diastolic apical rumble from regurgitant jet vibrating anterior mitral leaflet
- Peripheral signs: Quincke pulse, De Musset head bobbing, Duroziez femoral bruit; acute AR presents with cardiogenic shock/pulmonary edema
03
Pathophysiology
- Incompetent valve → diastolic regurgitation into LV → volume overload
- LV compensates via eccentric hypertrophy (dilation + wall thickening) to maintain SV
- Increased total SV raises systolic BP; runoff back into LV drops diastolic BP → wide pulse pressure
- Decompensation: LV dilates beyond reserve → EF falls → heart failure; acute AR has no time to compensate → flash pulmonary edema
04
Diagnostics
- TTE (echocardiography) — first-line and gold standard for diagnosis and severity
- Key echo metrics: regurgitant fraction, LV end-systolic diameter >50 mm, LVEF <55% trigger surgery
- CXR: cardiomegaly, dilated aortic root; ECG shows LVH pattern
- Cardiac MRI: best quantification of regurgitant volume when echo is suboptimal
- Cardiac cath used pre-operatively or when noninvasive data is discordant
05
Management
- Chronic compensated AR: serial echo surveillance every 1–2 years
- Vasodilators (ACE inhibitors, nifedipine) for hypertension or to temporize until surgery
- AVR indications: symptomatic AR, LVEF <55%, LV end-systolic diameter >50 mm, or concomitant cardiac surgery
- Acute severe AR: surgical emergency — urgent AVR; bridge with IV nitroprusside
- Avoid beta-blockers in acute AR (bradycardia prolongs diastole, worsening regurgitation); IABP is contraindicated
06
Clinical pivots
How to separate this script from the look-alikes that show up on exams and on the wards.
Aortic Stenosis
AS causes a systolic crescendo-decrescendo murmur radiating to carotids with narrow pulse pressure; AR causes a diastolic murmur with wide pulse pressure.
Mitral Stenosis
MS produces a low-pitched mid-diastolic rumble at the apex with an opening snap and no peripheral pulse signs; AR is a high-pitched early diastolic murmur with wide pulse pressure.
Pulmonary Regurgitation (Graham Steell murmur)
PR is also an early diastolic decrescendo at left sternal border but occurs in the setting of pulmonary hypertension with a loud P2 and RV heave; AR has wide pulse pressure and peripheral signs.
Patent Ductus Arteriosus
PDA produces a continuous machinery murmur peaking at S2, not isolated to diastole, and is heard best at the left infraclavicular area.
Keep reading
Full library- Aortic DissectionTear in aortic intima allows blood to enter and split the media, creating a false lumen; classified Type A (ascending) vs Type B (descending).
- Asthma ExacerbationAcute worsening of reversible airflow obstruction from bronchospasm, mucosal edema, and mucus plugging in a known or new asthmatic.
Educational use only. This illness script is a study framework, not medical advice. Confirm decisions with current guidelines and your clinical supervisors.