Which statement best describes the pathophysiology of cardiac tamponade?

Which statement best describes the pathophysiology of cardiac tamponade?

• A. Increased intrapericardial pressure compresses the heart, limiting diastolic filling
• B. The heart becomes hyperdynamic with decreased venous return
• C. The left ventricle increases ejection fraction
• D. The pericardial sac thickens with fibrosis

Answer: (A)

In tamponade, fluid buildup in the pericardial sac raises intrapericardial pressure enough to physically compress the heart. That external pressure prevents the ventricles from expanding adequately during diastole, so they fill poorly (reduced preload). With less filling, stroke volume and cardiac output fall. Because the pressure is applied around all chambers, diastolic pressures tend to equilibrate, and the patient develops signs of reduced forward flow and venous congestion. This description best fits the scenario because it directly links increased pericardial pressure to restricted diastolic filling and decreased cardiac output. The other ideas don’t match: a hyperdynamic state with decreased venous return isn’t typical of tamponade, and increased left ventricular ejection fraction isn’t the defining feature. Thickening of the pericardium with fibrosis points to constrictive pericarditis, not acute tamponade.

In tamponade, fluid buildup in the pericardial sac raises intrapericardial pressure enough to physically compress the heart. That external pressure prevents the ventricles from expanding adequately during diastole, so they fill poorly (reduced preload). With less filling, stroke volume and cardiac output fall. Because the pressure is applied around all chambers, diastolic pressures tend to equilibrate, and the patient develops signs of reduced forward flow and venous congestion.

This description best fits the scenario because it directly links increased pericardial pressure to restricted diastolic filling and decreased cardiac output. The other ideas don’t match: a hyperdynamic state with decreased venous return isn’t typical of tamponade, and increased left ventricular ejection fraction isn’t the defining feature. Thickening of the pericardium with fibrosis points to constrictive pericarditis, not acute tamponade.