• Two-layered sac which encircles the heart; inner serosal layer (visceral layer) and tough fibrous outer layer (parietal).
• layer of lymph in between
• Three functions: fixes heart within mediastinum and limits its motion, prevents extreme dilatation of the heart during sudden rises of intracardiac volume, and functions as a barrier to limit infection. Heart can function fine without pericardium.

• Fluid inside pericardium (Pericardial effusions) – problem with filling of the heart Þ cardiac tamponade
• Types: Idiopathic (inflammatory), myocardial infarction, trauma (stab and gunshot wounds), connective tissue disease (rheumatic fever, LE), specific infections (bacterial, tuberculosis, fungus, viral), metastic malignancy, aortic aneurysm (rupture), radiation, uremia, and post thoracotomy syndrome. Main cause is viral infections recently.
• Pericardial Effusion – Accumulation of fluid in the pericardial sac
• Rapid: a few 100 cc can cause cardiac compression and tamponade; trauma, accidents.
• Slow: fibrous wall can stretch gradually; 1000 cc may not cause cardiac tamponade; pericardium can stretch.
• Cardiac Tamponade – impairment of diastolic filling of the heart caused by an unchecked rise in intrapericardial pressure.
• Cardiac tamponade = pericardial effusion + hemodynamic features of cardiac compression.
• Die from hypotension; inject saline into pericardium and look at pericardial pressure Þ at a certain point the intrapericardial pressure Þ ß CO and ß BP.
• Pathophysiology:
• Vena cava and atria compressed by intrapericardial pressure Þ venous return impaired Þ Ý venous pressure
• Atrial and ventricular end-diastolic pressure increasesÞ effective ventricular filling and volume fallÞ ß SV Þ ß CO Þ ß arterial and pulmonary pressures Þ Shock
• Equalization of pressures in diastole
• Compensatory mechanism: Ý Central Venous Pressure ; Ý HR, Ý peripheral resistance.
• Clinical Manifestations:
• Presents with chest pain, friction rub, ST elevation (1-2 mm rise) in all leads, sitting down leaning forward, pain increases with inspiration.
• Friction rub – systolic, diastolic, atrial contraction – 3 components
• Dyspnea, Ý venous pressure, ß systemic arterial blood pressure, paradoxical pulse. Kussmaul’s sign Þ more distention on inspiration.
• Paradoxical Pulse Þ decrease in systemic blood pressure (> 10 mmHg) is exaggerated with inspiration.
• Normal: Ý venous return to right ventricle, pooling of blood in lungs, decreased left venous return, decrease in systolic pressure of 0-10mmHg.
• Inspiration: Pooling of blood in lungsÞ ß left venous return Þ ß SV Þ ß in systolic pressure.
• Pericarditis: Increase venous return to RVÞ Ý intrapericardial pressureÞ further compression of LVÞ ß SV Þ ß in systolic pressure.
• When both ß in SV and ß systolic pressure are added Þ ß ß BP.
• Treatment: needle aspiration, blood transfusion (diuretics are contraindicated), specific treatment, surgery.

 Chronic Pericarditis (Constrictive)

• Fibrous pericardial scar with calcification.
• Etiology: Idiopathic, specific infections (tuberculosis, bacterial, viral or fungus), connective tissue disease, occasionally due to tumor metastasis, post-irradiation, and uremia .
• Pathophysiology: elevated venous pressure, simulation of cirrhosis of the liver (ascites, hepatomegaly).
• Clinical Manifestations: distended neck veins, ascites, hepatomegaly, splenomegaly, fatigue, paradoxical pulse (40%), pericardial knock 0.06-0.12 sec after A₂. Heart sounds can be diminished.
• Chest x-ray: normal cardiac silhoutte, clear lungs, calcificaiton of pericardium
• ECG: low voltage, a. fibrillation can be present.
• Cardiac catheterization: equalization of elevated diastolic pressure in RA, RV, PA, and pulmonary artery wedge pressure. Ventricular diastolic dip. Elevated M-pattern right atrial pressure, drop in x and y descent.
• Treatment: surgical resection of pericardium.