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What are the functions of the pericardium? (3)
prevent acute dilatation, compliance, barrier
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Why are chronic pericardial effusions better tolerated than acute?
they activate the same compensatory mechanisms as in heart failure to increase filling and maintain CO
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What's a major difference between dogs and cats with peritoneopericardial diaphragmatic hernia?
- dogs often contain intestines and require surgical correction
- cats often contain only fat and liver and may be an incidental finding
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How do you diagnose peritoneopericardial diaphragmatic hernia?
radiography and ultrasound
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How can you manage peritoneopericardial diaphragmatic hernia?
Surgery- not necessary in all cases (6 year old cat with just fat and liver and no other signs....shouldn't go to surgery)
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What is the pathognomonic radiographic finding with peritoneopericardial diaphragmatic hernia?
persistent mesothelial remnant (dorsal communication of the hernia) [also suggestive: extremely large cardiac silhouette]
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What are the 3 classifications of pericardial effusion?
transudate, exudate (septic or sterile), hemorrhage
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Hardware disease causes ___________.
fibrinosuppurative pericarditis
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Recurrent infection or hemorrhage of the pericardium eventually leads to _____________.
constrictive pericardial disease (organized fibrin becomes fibrous connective tissue)
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What are the 2 most common causes of hemorrhagic pericardial effusion in dogs, and in what age group does each occur?
- Idiopathic- young dogs
- Neoplastic- old dogs
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What types of neoplasms most commonly cause hemorrhagic pericardial effusions in dogs? (6)
hemangiosarcoma, chemodectoma (aortic body tumor/ heart base tumor), mesothelioma, ectopic thyroid carcinoma, lymphoma (more common in cows and cats), metastatic neoplasia
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What is the definition of cardiac tamponade?
right-sided cardiac compression resulting from rise in intrapericardial fluid pressure (which is normally subatmospheric) with clinical signs
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What are the 2 ways patients present with cardiac tamponade?
- acute: reduced filling and hypotension
- chronic: compensations lead to R- or biventricular CHF
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What is an important therapeutic point concerning acute cardiac tamponade?
tap the effusion!!! removing even a little portion of the pericardial pressure leads to rapid relief of tamponade
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Describe the pathophysiology of cardiac tamponade.
fluid (pericardial effusion)—> pressure gets high enough and pericardium can no longer expand—> compression of right heart—> acutely, reduced filling of the heart, lower preload—>reduced CO and low BP—> chronically, patient retains fluid—> get really high venous pressures—> helps to fill central veins better in thorax—> better filling of RV due to higher pressure—> turns into congestive heart failure (ascites, congestion of liver, pleural effusion)
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What are the 3 pathophysiologies of pericardial effusion?
cardiac tamponade, constrictive disease, mass obstruction of venous return
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What clinical findings can be present with pericardial effusion? (9)
anorexia, depression, collapse/ weakness, distant heart sounds, elevated jugular venous pressure, abnormal arterial BP, friction rubs (LAs), pulsus paridoxicus, R-CHF
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What is pulsus paridoxicus?
- pulses get stronger as the animal expires and weaker as the animal inspires--> classic for cardiac tamponade
- during inspiration, the RV fills more, shifting the septum to the left, causing a decrease in LV filling and decreased SV and BP
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What are potential findings on ECG with pericardial effusion? (4)
- ST elevation (pericarditis), electrical alternans (very large effusions only), small complexes, cardiac rhythm disturbances
- these are all possible but not in every case
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What are radiographic findings that may be associated with pericardial effusion? (6)
globoid heart, sharp edges (not moving as much as they should be, usually "blurred"), rounding near LA, decreased pulmonary vascularity, +/- mass, pleural effusion
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Why SHOULDN'T you tap pericardial effusion in cats?
the most common reason for pericardial effusion in cats s CHF... treat the HF
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What are potential echocardiographic signs with pericardial effusion? (3)
sonolucent/mixed echoic space/fluid between the parietal pericardium and epicardium, compression/collapse of RA +/- RV, +/- mass lesion
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What is the principal therapy of pericardial effusion?
pericardiocentesis
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Why don't we use CHF drugs in the management of pericardial effusion?
they will reduce cardiac filling even more... BAD
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Why don't we use diuretic in CHF?
predispose to volume depletion; CO is already low
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What are the main indications for surgery with pericardial effusion? (2)
- pericarditis (to reduce the risk for constrictive disease)
- exploratory (FB or tumor)
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Subtotal pericardiectomy is indicated for... (3)
septic/inflammatory pericarditis, recurrent idiopathic pericardiac hemorrhage, exploratory examination/biopsy/pericardiectomy
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Classify the causes of pericardial effusion in cattle and the related prognosis. (3 causes)
- lymphosarc of the RA and ventricles-->hemorrhagic pericardial effusion (poor prognosis)
- perforating FB/ hardware--> fibrinosuppurative pericarditis and exudative effusion (poor prognosis)
- sterile idiopathic hemorrhagic pericarditis--> exudative effusion ad hemorrhage (poor prognosis)
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What are the classic clinical findings ("triad") of cardiac tamponade?
- low arterial BP
- distended jugular veins (increased JVP)
- distant, muffled heart sounds
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Chemodectoma occurs most commonly in ________.
old brachycephalic dogs
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