Ask the doctor

What causes fluid to build up around the heart and what can be done to treat it?

Q. My brother-in-law was told that he has some fluid around his heart. What does that mean, and how is it treated?

A. The heart is surrounded by a thin, two-layer sac called the pericardium. It looks a bit like a cellophane bag. The pericardium protects the heart, limits its motion, and prevents it from expanding too much when blood volume increases.