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Heart Valve Disease for USMLE Step 3

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Heart Valve Disease for the USMLE Step 3 Exam
Types of Heart Valve Disease
Heart valve disease includes stenosis and regurgitation affecting the aortic, mitral, tricuspid, and pulmonic valves.
Aortic Stenosis
  • Etiology:
    • Calcific Degeneration: Common in older adults.
    • Bicuspid Aortic Valve: Congenital defect that leads to early degeneration.
    • Rheumatic Heart Disease: Rare in developed countries, often affects multiple valves.
aortic valve stenosis
  • Pathophysiology: Stenosis creates left ventricular (LV) outflow obstruction, causing increased LV pressure and hypertrophy.
  • Clinical Presentation:
    • Symptoms: Dyspnea, angina, and syncope with exertion.
    • Heart Sound: Crescendo-decrescendo systolic murmur at the right upper sternal border, radiating to the carotids.
    • Pulsus Parvus et Tardus: Delayed and diminished carotid upstroke.
  • Diagnosis:
    • Echocardiography: Gold standard for assessing severity and LV function.
  • Management:
    • Aortic Valve Replacement (AVR): Indicated for symptomatic or severe cases; options include surgical or transcatheter replacement.
Aortic Regurgitation
  • Etiology:
    • Valve Disease: Bicuspid valve, infective endocarditis.
    • Aortic Root Disease: Aortic dissection, Marfan syndrome.
  • Pathophysiology: Regurgitation leads to LV volume overload, causing eccentric hypertrophy and progressive LV dilation.
  • Clinical Presentation:
    • Symptoms: Dyspnea, fatigue, and palpitations.
    • Heart Sound: High-pitched, decrescendo diastolic murmur at the left sternal border.
    • Widened Pulse Pressure: Signs include bounding pulses (e.g., Corrigan’s pulse).
  • Diagnosis:
    • Echocardiography: Assesses regurgitation severity and LV size.
  • Management:
    • Valve Replacement: Indicated for symptomatic patients or those with declining LV function.
    • Medical Therapy: Vasodilators (e.g., ACE inhibitors) in asymptomatic patients.
Mitral Stenosis
  • Etiology:
    • Rheumatic Fever: Most common cause, leading to leaflet thickening and fusion.
  • Pathophysiology: Narrowing of the mitral valve impedes blood flow from the left atrium to the LV, raising left atrial pressure and predisposing to atrial fibrillation and pulmonary hypertension.
  • Clinical Presentation:
    • Symptoms: Dyspnea, orthopnea, and hemoptysis.
    • Heart Sound: Low-pitched, rumbling diastolic murmur with an opening snap at the apex.
  • Diagnosis:
    • Echocardiography: Defines stenosis severity and left atrial size.
  • Management:
    • Percutaneous Mitral Balloon Valvotomy: Preferred for symptomatic patients with severe stenosis.
    • Anticoagulation: Necessary if atrial fibrillation is present.
Mitral Regurgitation
  • Etiology:
    • Primary: Mitral valve prolapse (MVP), infective endocarditis.
    • Secondary: Left ventricular dilation from ischemic or non-ischemic causes.
  • Pathophysiology: Regurgitation causes left atrial and LV volume overload, resulting in dilation and heart failure if severe.
  • Clinical Presentation:
    • Symptoms: Dyspnea, fatigue, and reduced exercise tolerance.
    • Heart Sound: Holosystolic murmur at the apex, radiating to the axilla.
  • Diagnosis:
    • Echocardiography: Key for evaluating regurgitation severity and LV function.
  • Management:
    • Surgical Repair or Replacement: Indicated in symptomatic patients or those with LV dysfunction.
    • Medical Therapy: Diuretics and vasodilators for symptom relief if surgery is delayed.
Tricuspid and Pulmonic Valve Disease
  • Tricuspid Regurgitation:
    • Usually secondary to right ventricular (RV) dilation from pulmonary hypertension or left-sided heart disease.
    • Presents with a holosystolic murmur at the left sternal border that increases with inspiration (Carvallo’s sign).
    • Managed with diuretics for volume control; surgery for severe cases.
  • Pulmonic Stenosis:
    • Primarily congenital, characterized by a systolic murmur at the left upper sternal border.
    • Severe cases are treated with balloon valvuloplasty.
  • Pulmonic Regurgitation:
    • Often secondary to pulmonary hypertension.
    • Typically asymptomatic; management focuses on treating the underlying cause.
Key Points
  • Aortic Stenosis: Presents with dyspnea, angina, and syncope; treated with valve replacement for symptomatic or severe cases.
  • Aortic Regurgitation: Causes wide pulse pressure and dyspnea; valve replacement recommended if symptomatic or if LV dysfunction develops.
  • Mitral Stenosis: Often due to rheumatic heart disease, presenting with dyspnea and diastolic murmur; managed with balloon valvotomy or anticoagulation if atrial fibrillation is present.
  • Mitral Regurgitation: Causes exertional dyspnea and holosystolic murmur; surgery indicated for symptomatic cases or LV dysfunction.
  • Tricuspid and Pulmonic Valve Disease: Tricuspid regurgitation often secondary to RV dilation; pulmonic stenosis is congenital and treated with balloon valvuloplasty if severe.

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