What is cardiac tamponade?

• A. A mild fluid around the heart causing no symptoms.
• B. A congenital defect.
• C. A medical emergency where the pericardial sac fills with blood, preventing the heart from functioning properly.
• D. An infection of the pericardium.

Answer: (C)

Cardiac tamponade is a dangerous condition in which fluid accumulates in the space around the heart (the pericardial sac) quickly enough to compress the heart and prevent it from filling properly during diastole. When the heart can’t fill, its ability to pump blood drops, leading to low blood pressure, fast heart rate, and signs of reduced cardiac output. The reason this is treated as a medical emergency is that even small amounts of rapidly accumulating fluid can cause life-threatening hemodynamic collapse, so urgent relief of the pressure—usually by draining the fluid—is essential. This scenario is different from a simple pericardial effusion that causes few or no symptoms, and it’s distinct from infections of the pericardium or congenital defects, which have other mechanisms and presentations. In tamponade you may also see signs like distended neck veins and muffled heart sounds, reflecting the heart being squeezed by the fluid.