The early symptoms of acute pericarditis are pain, which is located behind the sternum or in the precordial area, typically seen in the fibrin exudative type of inflammation. This pain arises from the friction between the visceral pericardium and the parietal pericardium. The nature of the pain is very sharp and related to respiratory movement, commonly exacerbated by coughing, deep breathing, or swallowing. The pain can radiate to the neck, left shoulder, and left arm. As fluid accumulates in the pericardium and the two layers of the pericardium separate, the pain may decrease or disappear.