Pericardial Disease

Question 1

Which breeds are predisposed to PE?

Answer 1

Golden retriever ** (more echo negative)
German shepherd dog (more echo positive)
St Bernard - present younger
Crossbreed 
Labrador 
Newfoundland 

N.B echo negative are more likely to be male

Question 2

What are the most common clincal signs in PE cases?

Answer 2

muffled heart sounds (74 percent),
weakness or lethargy (73 per cent),
ascites (68 per cent) More in echo negative
exercise intolerance (57 per cent)
Collapse - more common in echo positive dogs
Cough

Question 3

What are common clin path findings?

Answer 3

Non regenerative anaemia

Rarely low TP

Question 4

What may you see on rads with PE?

Answer 4

Cardimegaly with a globoid heart in most (not all)
1/3 will have pleural effusion
May see a mass

Question 5

What is the risk of peri-operative death with pericardiectomy?

Answer 5

13% die

Question 6

What means the PE animal has a worse prognosis?

Answer 6

Presents collapsed
Not having ascites
Echo positive

Question 7

What is the role of the normal pericardium?

Answer 7

• Maintain heart in normal position in mediastinum /thoracic cavity
• Protect the heart
• Prevent excessive dilatation of heart chambers
• Preserve normal ventricular interdependence
• “Lubrication” – normally 0.25 mLs/ kg body weight pericardial fluid.

Question 8

What is cardiac tamponade?

Answer 8

• “Collapse” of the right atrium, usually during ventricular diastole, if pericardial pressure > right atrial pressure.
• May also see tamponade (“collapse”) of the RV.
• Seen on echocardiography.
• If the animal has R-CHF signs with a pericardial
effusion, it will have cardiac tamponade.

Question 9

What are possible clinical signs of PE?

Answer 9

Right sided congestive heart failure (R-CHF) (if chronic)
• Ascites
• Distended jugular veins
• Positive hepatojugular reflux
• Hepatomegaly (may have ALT)
• +/- Pleural effusion

Forward heart failure (acute or chronic)
• Lethargy / exercise intolerance / collapse
• Weak femoral pulses
• Variable pulse quality with respiration (pulsus paradoxus)
• Pallor, slow capillary refill
• Blood pressure may be low (e.g. SBP <100 mmHg)

Muffled heart sounds?
• Not always – especially if bloody effusion

Question 10

What is pulsus paradoxus?

Answer 10

Almost pathognomic for PE
• Inspiration: greater venous return to right heart (due to negative thoracic pressure).
• This then “compresses” left heart, reducing LV filling.
• Reduced cardiac output from left heart during inspiration, so reduced pulse volume.

Question 11

What are all the possible causes of PE?

In order of likelihood

Answer 11

• Idiopathic
• Neoplastic
• Septic (pericarditis)
• CHF (especially cats)
• Left atrial tear (dogs with MMVD)
• Coagulopathies (e.g. rodenticide intoxication)
• Systemic disease: SIRS (inflammatory disease), uraemia (especially cats), FIP, Hypoalbuminaemia

Question 12

Outline idiopathic PE

Answer 12

• Causes approximately 50% of canine PEs in general
practice
• Cause unknown; inflammatory process
• Usually haemorrhagic effusion (“port-wine” appearance) (often high PCV fluid)
• Large and giant breeds of dogs predisposed:
Labradors, Golden retrievers, St Bernards, Newfoundlands etc

Question 13

Outline haemangiosarcoma PE

Answer 13

• Predilection for RA / RA appendage or R AV groove
• Highly malignant / metastatic; need to screen for splenic or other lesions.
• Predisposed breeds: GSDs, Golden Retrievers recently, Bichon frisés in SATH), but any breed possible.
• Often heterogeneous echo appearance.
• Bleeds into pericardial space can be acute or chronic.
• Very guarded prognosis.
• Palliative pericardiocentesis?
• Metronomic chemotherapy?
• Tranexamic acid? (to reduce bleeds??)

Question 14

Outline chemodectoma PE

Answer 14

• Tumour of chemoreceptors, so most commonly Boxers or other brachycephalic breeds.
• Location: most commonly aortic arch / periaortic.
• Homogeneous appearance on echo.
• Very slow growing and rarely metastasize.
• Sometimes an incidental finding at PM or on echocardiography.
• Can result in pericardial effusion or “compression” of heart chambers, resulting in clinical signs.

Question 15

Can you FNA tumours of the heart

Answer 15

It is possible if you don’t have to go through major vessels/ lung

Question 16

What less common neoplasias of the heart are there?

Answer 16

• Ectopic thyroid carcinoma (heart base mass)
• Lymphoma (may not have a mass lesion)
• Other cardiac neoplasia may occur without causing pericardial effusion, but mass lesions identified on
echocardiography.
• Mesothelioma

Question 17

Outline mesotheliomas as a cause of PE

Answer 17

• Difficult to diagnose as no mass lesions identified on
echocardiography
• May have tricavitatory effusions.
• Cytology: difficult to distinguish between reactive mesothelial cells in an effusion and neoplastic mesothelial cells.
• Even histopathology of pericardium may not confirm diagnosis.
• Some dogs treated for idiopathic can develop mesotheliomas years later

Question 18

How can you try to distinguish between idiopathic PEs and neoplastic ones

Answer 18

Cytology - more useful if PCV <10%

Troponin levels higher in haemangiosarcs, mid range for some neoplasias, low if idiopathic (not 100% accuracy)

Question 19

Outline septic pericarditis

Answer 19

• Rare in small animals
• Most commonly seen in gundog breeds (especially
spaniels); thought to be due to initiating foreign body
of organic material, but often not proven).
• Dog is unwell, usually febrile.
• Diagnosis based on cytology (& culture / sensitivity).
Lavage and pericardectomy

Question 20

What may you see on ECG with PE

Answer 20

• Pericardial effusion may result in low amplitude QRS
complexes (“damping”)
• May see variable height of R waves - called electrical
alternans. This is due to the heart swinging in the
pericardial effusion, so altering position relative to recording electrodes.
• Not always present, but typical of PE if seen.
• Usually sinus tachycardia with significant PE.
• Note: the ECG should be monitored during pericardiocentesis ventricular ectopics occur if the heart is touched with the catheter.

Question 21

What are the roles of pericardiocentesis?

Answer 21

• For diagnostic purposes (fluid analysis may give
diagnosis, especially cytology)
• For therapeutic purposes. Draining the pericardial effusion immediately improves preload (venous return to the heart) and therefore cardiac output.
• EMERGENCY treatment, if the patient is HYPOTENSIVE

Question 22

What should and shouldn’t you give PE patients?

Answer 22

• With improved venous return, the R-CHF resolves without further treatment.
• DO NOT GIVE diuretics or vasodilator drugs before
pericardiocentesis. They will further reduce preload and further compromise cardiac output.
• DO GIVE intravenous fluid therapy; improves preload so maintains cardiac output, especially if the dog is
hypotensive (or if sedation required).

Question 23

How do you prep a patient for pericardiocentesis?

Answer 23

• Sedation: normally required if the patient is not collapsed. E.g. Butorphanol.
• Pericardiocentesis generally by right hemithorax (avoids coronary arteries on left heart)
• Clip and aseptically prepare the skin
• +/- sterile drape
• Pericardiocentesis site is generally 5th intercostal space, costocondral junction. Can be ultrasound guided.
• Local anaesthetic infiltration into the skin, intercostal space and pleurae.

Question 24

What is the basic procedure for pericardiocentesis?

Answer 24

• Large bore, sufficiently long IV catheter (e.g. 14G).
• Consider adding side-holes with scalpel blade (but no more than one-third of circumference)
• With syringe attached, introduce catheter into the
pericardial effusion, remove syringe & stylet.
• Connect 3-way tap (possibly with extension tubing)
• With syringe, continue to drain pericardial effusion,
emptying into a jug.
• Measure what you have removed.
• Remember to do PCV (compare with blood PCV) and
keep fluid for analysis (especially cytology)

Question 25

What is constrictive or constrictive effusive pericardial disease?

Answer 25

• Uncommon
• May be consequence (endstage) of chronic or recurrent pericardial effusions (whatever the initial cause)
• Severe thickening of both the parietal and visceral
pericardium; adhesions.
• May be associated with small amount of residual pericardial effusion (constrictive effusion).
• Constricts the heart so venous return is compromised.
• If no fluid, difficult diagnosis to make (advanced
echocardiography or cardiac catheterisation)

Question 26

Outline PPDH

Answer 26

Peritoneo-Pericardial Diaphragmatic Hernia
• Failure of embryological closure of the diaphragm (septum transversum)
• Residual communication between the pericardial sac and abdominal cavity (variable size).
• Abdominal organs can be located within the pericardial scan.
• May result in pericardial effusion (e.g. herniated fat or liver)
• May result in GI signs of obstruction (herniated gut or stomach).
• Often NO clinical signs; diagnosed as an incidental finding.
• Predisposed breeds: Weimaraner. Pedigree, long-haired breeds of cat (e.g. Himalayan, Maine coon).

Question 27

Outline pericardial cysts

Answer 27

Tend to be on the RHS, can expand and fill with fluids and compress the RHS of the heart,
Some can be easily shelled out

Question 28

What is a closed PPDH?

Answer 28

No apparent communication, but can get things like encapsulated fat stuck

Question 29

Outline pericardial defects

Answer 29

• Rarely diagnosed except at PM
• Usually incidental finding
• If herniated heart chamber through the defect, may
cause issues (especially if that chamber dilates – e.g.
herniated left atrial appendage and then development
of MMVD).
• Usually needs CT to diagnose