Pericardial Effusion Flashcards
What are the 4 functions of the pericardium?
- tethers heart into place in the chest
- limits cardiac filling and ventricular compliance
- physical protective barrier from lungs and thorax
- lubricates moving surfaces of the heart
What affect does pericardial effusion have on the heart?
- increased intracardiac pressure around the entirety of the heart
- this decreases venous return, ventricular filling, and CO
- RV = increased venous pressure, jugular venous distension, hepatic congestion, ascites, peripheral edema
- LV = systemic hypotension, weakness, tachycardia
Would Furosemide help treat pericardial effusion?
no —> decreases BP and preload, which are already low and only thing keeping blood in circulation
What cardiac tamponade? What does this cause?
cardiac compression resulting from a rise in intraparticardial pressure due to effusion build up in the pericardial sac
compression of RA, RV, and cranial vena cava = heart cannot fill properly
How does acute and chronic presentation with pericardial effusion differ?
ACUTE = reduced filling and hypotension - cardiogenic shock —> rapid onset of weakness, collapse, death
CHRONIC = low CO compensation causes right-sided CHF or biventricular failure —> exercise intolerance, abdominal distension, weight loss, coughing
What are the 4 most common PE findings indicative of pericardial effusion? What else is seen?
- muffled heart sounds
- poor pulse quality (will improve following a tap!)
- pale MM
- jugular distension, right heart failure
- tachycardia
- pulsus paradoxus
- ascites
- tachypnea
What is pulsus paradoxus? Why does this occur?
pronounced variation in cardiac filling over the respiratory cycle
arterial blood pressure decreases during inspiration (less LV filling), resulting in weaker femoral pulses
How is BP affected by pericardial effusion?
hypotensive
How does signalment affect etiology of pericardial effusion?
YOUNG - congenital PPDH or pericardial cyst
OLDER - neoplasia, idiopathic, heart failure, left atrial tear, infection, metabolic/toxins (uremia, coagulopathy)
PPDH:
Middle-aged to older patient with pericardial effusion:
What is the most common neoplasia in dogs that can lead to pericardial effusion? What dog is most commonly predisposed?
HSA of the right auricle —> high rate of malignancy, 8-25% of dogs with splenic tumors have RA tumors (observe heart before splenectomy)
Golden Retriever
Where are chemodectomas most commonly found? What breeds are predisposed?
heart base (aorta or pulmonary artery) —> late metastasis, slow growing = decent prognosis until it presses on heart and organs
M>F brachycephalics
What is restrictive pericarditis? What are 3 causes?
stiff pericardium +/- effusion impairs filling by preventing late diastolic expansion, causing signs of right-sided CHF
- chronic inflammation/infection
- recurrent hemorrhage
- calcification
What are the 2 most common causes of infective pericarditis? How does it appear grossly?
- bacterial/fungal contamination from migrating grass awns or penetrating FB
- FIP
flocculent and suppurative
What are 5 bacterial/fungal agents that can cause pericarditis?
- Bacterioides
- Actinomyces
- Streptococcus
- Pasteurella
- Coccidioides immitis (Valley Fever)
What are the 2 most common cardiovascular causes of pericardial effusion?
- LA rupture - mitral regurgitation from CVD (small breeds!)
- CHF - rarely enough fluid to cause significant hemodynamic compromise (cat > dog)
What are the 3 most common metabolic causes of pericardial effusion?
- uremia
- hypothyroidism - cholesterol-based effusion
- hyperthyroidism (cats) - small effusions without heart disease
What toxin most commonly causes pericardial effusion?
anticoagulant rodenticide —> coagulation disorders, DIC
What laboratory tests are most commonly recommended for possible cases of pericardial effusion?
- CBC/Chem
- fluid cytology
- culture
- fungal titers
- coagulation panel
- biomarkers (not as helpful)
How does the type of effusion give information about possible causes of pericardial effusion?
- transudate/modified transudate - hernia, cyst, CHF, hypoproteinemia, chemodectoma
- exudate - FB, idiopathic inflammation, Nocardia, fungal, FIP
- hemorrhage - HSA, chemodectoma, ectopic thyroid, mesothelioma, lymphoma, metastasis, LA rupture, coagulopathy
In what way is pericardial fluid analysis not as helpful for diagnosing cause of pericardial effusion? What are some occasional positive findings?
neoplasia —> typically do not exfoliate well (reactive mesothelial cells common)
- lymphoma
- infectious
What is the most common rhythm seen on ECG in cases of pericardial effusion? What 2 changes are seen?
sinus tachycardia
- dampened amplitude of QRS complexes
- electrical alternans - heart swings in pericardium
What are the 2 most common findings in cases of pericardial effusion on radiographs? What else is seen?
- globoid cardiac silhouette
- crisp cardiac margins
- dorsal deviation of trachea
- small/enlarged caudal vena cava
- small pulmonary vasculature
- pleural effusion
What 3 limitations are there with diagnosing pericardial effusion of radiographs?
- cannot determine etiology (unless PPDH)
- severe cardiac dilation (DCM) can mimic effusion
- large amount of pleural effusion can high cardiac silhouette
What is the gold standard for diagnosing pericardial effusion?
echo —> confirms effusion, determines etiology, can r/o structural heart disease
What treatment is recommended in acute cases of pericardial effusion? What is avoided?
- pericardiocentesis - do not delay if in cardiogenic shock
- rapid fluid resuscitation (only if going to tap the heart!) - only way for heart to get blood is by increasing volume to the heart
diuretics —> decreases BP
When is pericardiocentesis indicated? Is it commonly done in cats?
- evidence of hemodynamic compromise - tachycardia, weakness, hypotension
- moderate to large volume of pericardial effusion
no —> effusion is the main manifestation of heart failure
What equipment is used for pericardiocentesis?
- over-the-needle catheter
- extension IV set
- three-way stopcock
- syringe
- scalpel blade
- collection bowl
- graduated cylinder
- red top and lavender top tubes
- sterile gloves
- local anesthetic block
- continuous ECG
How is pericardiocentesis performed? What sedation can be used?
- place patient in lateral or sternal recumbency - safest on right side due to the cardiac notch, which helps avoid major cardiac vasculature on the left
- shave and scrub 4th-6th ICS (if time allows)
- tap cranial to the rib to avoid IC arteries, veins, and nerves
Butorphanol - rapid and short acting to not affect hypotension as much
What does it mean if blood from a pericardiocentesis clots?
frank blood —> likely blood from chambers in the heart
- fluid in pericardium will not clot due to loss of clotting factors and dilution decreasing PCV
What 2 complications are associated with pericardiocentesis? What monitoring should be performed?
- arrhythmias, usually ventricular (Lidocaine!)
- laceration/puncture of heart/lungs (pneumothorax)
- BP
- attitude
- observe in hospital for 12-24 hours and recheck in a week for reaccumulation, then every 2-4 weeks
What are 3 options for treatment of chronic pericardial effusion?
- percardiectomy - not recommended for neoplastic causes (except chemodectoma!), only option for constrictive pericardial disease
- balloon pericardiotomy
- medical - steroids for idiopathic disease, chemotherapy and radiation to decrease bleeding and tumor growth
What is the most common cause of pericardial effusion in cats? What are some other causes?
CHF
- PPDH
- neoplasia
- FIP
- hyperthyroidism (tapping not necessary)
What treatment is most commonly recommended for pericardial effusion in cats? What is rarely needed?
treat underlying cause - Furosemide, Pimobendan
pericardiocentesis - only if there is a large amount of volume causing an issue, not heart-failure associated, or hemodynamically compromised
