diseases of pericardium

Question 1

Pericardial anatomy

Answer 1

pericardium is composed of 2 layers
Visceral pericardium- membrane of a single layer of mesothelial cells, similar to pleural and peritoneal cavity
Adherent ot the epicardial surface of the heart

Parietal pericardium: fibrous layer 2 mm thick, collagen and elastic fibers, Collagen (low levels of stretch - wavy bundle, High levels of stretch–straight bundles), reflects the mechanical characteristics of the pericardial tissue

Question 2

Pericardial anatomy

Answer 2

the visceral pericardium reflects back near the origin of the great vessels and becomes the parietal pericardium, pericardial space (contains 50 ml serous fuid, part of posterior wall of the left atrium is extrapericardial)

Stabilized by ligamentous attachments to the diaphragm, sternum, spine

Phrenic nerve enveloped by parietal pericardium, phrenic nerve irritation–> hiccups

Question 3

Function of the pericardium

Answer 3

Maintains heart position, lubrication of visceral and parietal layers barrier to infection, prostaglanding secretion, modulation of Coronary vascular tone

Restraining effect on cardiac volume, mechanical properties of pericardial tissue, small reserve volume, tensile strength, normal cardiac volume (more elastic–stretches easily), increase cardiac volumes, pericardial tissue becomes stiff (resistant to further stretch)

Question 4

pericardial physiology

Answer 4

flat compliant segment transitions relatively abruptly to a non compliant segment, practical significance in pericardial effusion. critical volume of effusion is reached small adittional amount lead to larger increase in intrapericardial pressure. Removal of small amount of fluid–> improvement of pressure

chronic cardiac dilatation results in adaptation to accomodate increased cardiac volumes

Pericardial growth occurs in response to chronic stretch, pressure volume curve shifts to the right with decreased slope, slowly accumulating pericardial effusions can become very large before symptoms (hypothyroidism)

Question 5

Acute pericarditis

Answer 5

acute pericardial inflammation, majority idiopathic (usually viral

symptoms - chest pain, better when sitting forward, worse when lying down, sharp pleurutuc like, substernal, dyspnea, caugh, hiccups fever

pericardial friction rub , sometimes tachycardia

ecg- ST elecation, upright t wave, pr depression,

treatment- cholchicineinhibits movements of intercellulat granules and the secretio of substances in leukocytes, peak conc, 16 times the peak in plasma