<unk>  is compression of the heart that occurs when blood or fluid builds up in the space between the myocardium (heart muscle) and the pericardium (outer covering sac of the heart). This prevents the ventricles from expanding fully. The excess pressure from the fluid prevents the heart from functioning normally.
Cardiac tamponade
Acute chest syndrome
Pneumopericardium
Myocardial rupture
Flail chest
Uremic pericarditis
Myopericarditis
Pericarditis