indications include cardiac tamponade, as well as the need to analyze the fluid surrounding the heart. cardiac tamponade is a condition in which an accumulation of fluid within the pericardium (pericardial effusion) creates excessive pressure, which then prevents the heart from filling normally with blood. this can critically decrease the amount of blood that is pumped from the heart, which can be lethal. the removal of the excess fluid reverses this dangerous process. examples of the need for fluid analysis would be to differentiate whether a fluid collection within the pericardium is due to an infection, spread of cancer, or possibly an autoimmune condition.