Which valvular heart disease is most commonly associated with syncope?

• A. Mitral stenosis
• B. Aortic stenosis
• C. Mitral regurgitation
• D. Aortic regurgitation

Answer: (B)

Exertional syncope is most characteristic of severe aortic stenosis. The narrowed aortic valve creates a fixed left ventricular outflow obstruction, so the heart cannot increase stroke volume during exercise. As vasodilation lowers venous return and blood pressure, cerebral perfusion drops and syncope can occur. This presentation is classically part of the angina–syncope–dyspnea triad seen with severe AS. Other valvulopathies usually cause symptoms from volume overload or pulmonary congestion (mitral stenosis, mitral or aortic regurgitation) rather than sudden loss of consciousness during activity, so syncope is less typical for them.