The surgical puncture to remove fluid from the pericardial sac is known as pericardiocentesis, according to WebMD. The pericardial sac is a layer of tissue that surrounds a person's heart.
Sometimes, pericardiocentesis is referred to as a pericardial tap. It is most often performed in order to determine the type of fluid around the heart and the cause of it, as stated by the National Institutes of Health. Commonly, the fluid is tested for signs of an infection, cancer or to see if blood is present. Only an experienced medical professional can perform this test and interpret the results.