The presence of an area with an outer fibrous layer encapsulated by concentrated blood components and body fluids is often found, suggesting that intrapericardial hemorrhage is an important factor in the formation of pericardial constriction. Larger cardiac wounds, smaller pericardial wounds or periwound tissues blocked by blood clots. Acute intrapericardial hemorrhage of 100 to 200 ml can cause a sharp rise in pressure in the pericardial cavity, which affects the normal diastole of the heart and produces acute pericardial compression signs. The first to be pressurized are the vena cava and atria, resulting in an increase in central venous pressure and end-diastolic pressure, and a gradual rise in peripheral venous pressure. Initially, the blood pressure is normal or slightly elevated due to reflex constriction of the peripheral vessels. When the heart is severely restricted in diastole, the blood volume per beat is significantly reduced and the arterial pressure falls rapidly. When the pressure in the pericardial cavity rises to 17 cmH2O, so that no blood is expelled from the heart beat, the patient quickly enters the symptoms of shock unless the venous pressure is increased by rapid rehydration. Symptoms of acute pericardial compression include peripheral cold sweat, facial and lip cyanosis, shortness of breath, angry superficial neck veins, decreased blood pressure, fine and rapid pulse, and odd pulse. The classic Beck’s triad: distant heart sounds, decreased systolic blood pressure and elevated venous pressure when present, is helpful in the diagnosis of acute pericardial compression. However, only 35% to 40% of patients generally have all the typical symptoms. In fact, elevated venous pressures appear earliest and decreased arterial pressures appear later. Because the amount of blood in the pericardium is low in pericardial compression due to penetrating cardiac injury, and blood collects in the posterior pericardial cavity of the heart in the supine position, distant heart sounds are less common, but odd pulses are more common.