Fluid accumulates within the pericardial sac and compresses the heart; this condition is called:

• A. Pulmonary edema
• B. Tension pneumothorax
• C. Aortic dissection
• D. Cardiac tamponade

Answer: (D)

Fluid building up inside the pericardial sac creates pressure around the heart, especially during diastole, which prevents the ventricles from filling properly. When filling is restricted, preload drops, stroke volume falls, and cardiac output declines, leading to shock-like symptoms. This situation is cardiac tamponade.

It’s different from pulmonary edema, which is fluid backing up into the lungs from heart failure; from tension pneumothorax, where air in the chest cavity compresses the heart and great vessels; and from aortic dissection, a tear in the aorta causing chest pain and potential shock. The hallmark here is the pressure on the heart itself from the fluid in the pericardial sac.