What can cause a pericardial effusion according to the provided material?

• A. Cardiac chamber perforation
• B. Atherosclerotic plaque in coronary arteries
• C. Pulmonary embolism
• D. Myocardial infarction without pericarditis

Answer: (A)

Fluid in the pericardial sac most often comes from a direct leakage into that space, such as when a cardiac chamber is perforated. A perforation allows blood from the heart to spill into the pericardial cavity, creating a hemopericardium and often a pericardial effusion with potential tamponade. This direct mechanism makes cardiac chamber perforation the best fit for causing a pericardial effusion.

The other options don’t fit as well because they describe processes that affect the heart or vessels but do not reliably produce fluid accumulation in the pericardial space on their own. Atherosclerotic plaque in the coronary arteries leads to ischemia and myocardial infarction, not a direct pericardial effusion. Pulmonary embolism can be associated with a small effusion but is not a primary or common cause. Myocardial infarction without pericarditis implies no pericardial inflammation or fluid accumulation, whereas effusions related to infarction typically occur with concurrent pericarditis.