Pericardial Disease Flashcards
Which breeds are predisposed to PE?
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
What are the most common clincal signs in PE cases?
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
What are common clin path findings?
Non regenerative anaemia
Rarely low TP
What may you see on rads with PE?
Cardimegaly with a globoid heart in most (not all)
1/3 will have pleural effusion
May see a mass
What is the risk of peri-operative death with pericardiectomy?
13% die
What means the PE animal has a worse prognosis?
Presents collapsed
Not having ascites
Echo positive
What is the role of the normal pericardium?
- 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.
What is cardiac tamponade?
• “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.
What are possible clinical signs of PE?
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
What is pulsus paradoxus?
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.
What are all the possible causes of PE?
In order of likelihood
- 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
Outline idiopathic PE
• 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
Outline haemangiosarcoma PE
- 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??)
Outline chemodectoma PE
- 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.
Can you FNA tumours of the heart
It is possible if you don’t have to go through major vessels/ lung
What less common neoplasias of the heart are there?
• 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
Outline mesotheliomas as a cause of PE
• 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
How can you try to distinguish between idiopathic PEs and neoplastic ones
Cytology - more useful if PCV <10%
Troponin levels higher in haemangiosarcs, mid range for some neoplasias, low if idiopathic (not 100% accuracy)
Outline septic pericarditis
• 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
What may you see on ECG with PE
• 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.
What are the roles of pericardiocentesis?
• 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
What should and shouldn’t you give PE patients?
• 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).
How do you prep a patient for pericardiocentesis?
- 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.
What is the basic procedure for pericardiocentesis?
• 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)
