The clinical manifestations of acute pericarditis include symptoms and signs. The symptoms of acute pericarditis are pain behind the sternum and in the precordial region, which often occurs during the fibrinous exudative phase of inflammation. The pain can radiate to the neck, left shoulder, left arm, and even the upper abdomen. The nature of the pain is sharp, related to respiratory movements. As the condition progresses, the pain can disappear and be replaced by difficulty breathing. Some patients may develop significant pericardial effusion leading to cardiac tamponade, resulting in symptoms such as difficulty breathing, edema, and other related symptoms. During acute pericarditis, the most diagnostically valuable sign is the pericardial friction rub, typically located in the precordial area. A typical friction rub can be heard consistent with atrial contraction, ventricular contraction, and ventricular relaxation, known as a triphasic friction rub, and so on.