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Heart Valve Disease for USMLE Step 2

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Heart Valve Disease for the USMLE Step 2 Exam
Types of Heart Valve Disease
Heart valve disease can involve stenosis (narrowing) or regurgitation (backflow) of the four heart valves: aortic, mitral, tricuspid, and pulmonic. The most commonly affected are the aortic and mitral valves.
Aortic Stenosis
  • Etiology:
    • Calcific Degeneration: Most common cause in older adults.
    • Bicuspid Aortic Valve: Congenital, often leading to early calcification.
    • Rheumatic Heart Disease: Rarely affects the aortic valve alone and usually involves the mitral valve as well.
aortic valve stenosis
  • Pathophysiology: Stenosis causes left ventricular (LV) outflow obstruction, leading to LV hypertrophy as compensation for increased pressure.
  • Clinical Presentation:
    • Symptoms: Dyspnea on exertion, angina, and syncope (especially with exertion).
    • Heart Sound: Crescendo-decrescendo systolic murmur at the right upper sternal border, radiating to the carotids.
    • Pulsus Parvus et Tardus: Weak, delayed carotid pulse.
  • Diagnosis:
    • Echocardiography: Gold standard for assessing stenosis severity and LV function.
  • Management:
    • Aortic Valve Replacement (AVR): Recommended for symptomatic patients or severe cases.
    • Transcatheter Aortic Valve Replacement (TAVR): An alternative for patients who are not surgical candidates.
Aortic Regurgitation
  • Etiology:
    • Valve Disease: Bicuspid valve, infective endocarditis.
    • Aortic Root Disease: Aortic dissection, connective tissue disorders (e.g., Marfan syndrome).
  • Pathophysiology: Regurgitation causes LV volume overload, leading to eccentric hypertrophy.
  • Clinical Presentation:
    • Symptoms: Dyspnea and fatigue.
    • Heart Sound: High-pitched, decrescendo diastolic murmur at the left sternal border.
    • Widened Pulse Pressure: Bounding pulses (e.g., Corrigan’s pulse in the carotids, Quincke’s pulse in the nail beds).
  • Diagnosis:
    • Echocardiography: Evaluates severity of regurgitation and LV dilation.
  • Management:
    • Surgical Valve Replacement: Indicated for symptomatic patients or those with LV dysfunction.
Mitral Stenosis
  • Etiology:
    • Rheumatic Fever: Most common cause worldwide.
  • Pathophysiology: Obstruction of blood flow from the left atrium to the LV leads to increased left atrial pressure, left atrial dilation, and pulmonary hypertension.
  • Clinical Presentation:
    • Symptoms: Dyspnea, orthopnea, and paroxysmal nocturnal dyspnea (PND).
    • Heart Sound: Low-pitched, rumbling diastolic murmur with an opening snap, best heard at the apex.
  • Diagnosis:
    • Echocardiography: Confirms stenosis and assesses left atrial size.
  • Management:
    • Percutaneous Mitral Balloon Valvotomy: First-line for symptomatic patients with severe stenosis.
    • Rate Control and Anticoagulation: For patients with atrial fibrillation.
Mitral Regurgitation
  • Etiology:
    • Primary: Mitral valve prolapse (MVP), infective endocarditis, rheumatic disease.
    • Secondary: LV dilation from ischemic or non-ischemic cardiomyopathy.
  • Pathophysiology: Causes left atrial and LV volume overload, leading to heart failure if severe.
  • Clinical Presentation:
    • Symptoms: Dyspnea, fatigue, and exercise intolerance.
    • Heart Sound: Holosystolic murmur at the apex, radiating to the axilla.
  • Diagnosis:
    • Echocardiography: Evaluates severity of regurgitation and LV function.
  • Management:
    • Surgical Repair or Replacement: Indicated in symptomatic patients or those with LV dysfunction.
    • Medical Management: Diuretics and vasodilators for symptom control.
Tricuspid and Pulmonic Valve Disease
  • Tricuspid Regurgitation:
    • Often secondary to right ventricular dilation from pulmonary hypertension or left-sided heart disease.
    • Presents with a holosystolic murmur that increases with inspiration (Carvallo’s sign).
    • Managed with diuretics; surgery is reserved for severe cases.
  • Pulmonic Stenosis:
    • Often congenital, presenting with a systolic murmur at the left upper sternal border.
    • Balloon valvuloplasty is the treatment of choice for severe cases.
  • Pulmonic Regurgitation:
    • Often due to pulmonary hypertension, typically asymptomatic.
    • Management focuses on treating the underlying condition.
Key Points
  • Aortic Stenosis: Presents with exertional dyspnea, angina, and syncope; treated with valve replacement if severe.
  • Aortic Regurgitation: Symptoms include dyspnea and fatigue; features widened pulse pressure. Replacement indicated in symptomatic patients or those with LV dysfunction.
  • Mitral Stenosis: Most commonly caused by rheumatic fever, presents with dyspnea and diastolic murmur. Percutaneous valvotomy is the treatment of choice.
  • Mitral Regurgitation: Presents with exertional dyspnea and holosystolic murmur; surgical repair/replacement is indicated if symptomatic or if LV function is compromised.
  • Tricuspid and Pulmonic Valve Disease: Tricuspid regurgitation often secondary to RV dilation, managed with diuretics. Pulmonic stenosis is typically congenital and treated with balloon valvuloplasty if symptomatic.

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