Pericardial disease

Question 1

Anatomy of the pericardium

Answer 1

Fibrinous pericardium (outer)

Serous pericardium (inner)
- Parietal layer
- Pericardial fluid
- Visceral layer

Question 2

Fibrinous pericardium (outer)

Answer 2

Thin, tough sac that is continuours with the adventitia of the great vessels dorsally and with the sterno-pericardial ligament ventrally

Question 3

Serous pericardium (inner)

Answer 3

Consists of two layers and the pericardial fluid between them.
A thin layer of mesothelial cells is present in the inner aspects of the layers

Parietal layer: inner surface of the fibrinous pericardium, composed of collagenous fibers

Pericardial fluid: between the layers, small volume, serous, thin, clear fluid

Visceral layer: forms the epicardium

Question 4

Blood supply to the pericardium

Answer 4

Via branches of the aorta, internal thoracic artery, and musculophrenic arteries

Question 5

Lymphatic drainage from the pericardium

Answer 5

Cardiac, mediastinal, and pre-sternal lymph nodes

Question 6

Function of the pericardium

Answer 6

Prevention of overdilation
Protection from infection
Maintain the heart in a fixed position within the thorax
Coordinates the left and right ventricular function

NOT VITAL

Question 7

Congenital pericardial disease

Answer 7

Peritoneopericardial diaphragmatic hernia (PPDH)

Pericardial cysts

Question 8

Peritoneopericardial diaphragmatic hernia (PPDH)

Answer 8

Defect in the ventral diaphragm and pericardium during embryonic development

Incomplete sepration of the thoracic and abdominal cavities

Most common congenital defect

Weimeraners and Persian cats

Often asymptomatic
Can be GI signs or less commonly resp signs

Surgical correction can be curative

Question 9

Pericardial cysts

Answer 9

Rare

Result from the entrapment of the omentum or falciform ligament in the pericardium

Often asymptomatic but can cause pericardial effusion and cardiac tamponade

Surgical removal is possible

Question 10

Acquired pericardial diseases

Answer 10

Pericardial effusion

Question 11

Categories of pericardial effusion

Answer 11

Haemorrhagic

Transudate

Exudate

Question 12

Causes of haemorrhagic pericardial effusion

Answer 12

Neoplastic

Idiopathic

Left atrial rupture

Coagulopathy

Trauma

Question 13

Causes of transudate pericardial effusion

Answer 13

Congestive heart failure

Neoplasia

PPDH

(Less common: hypoproteinaemia, uraemia with renal failure)

Question 14

Causes of exudate pericardial effusion

Answer 14

FIP

Infection

Foreign bodies

Question 15

Neoplastic pericardial effusions

Answer 15

Haemangiosarcoma

Chemodectomas (heart base tumour)

Mesothelioma

Question 16

Pericardial effusion caused by haemangiosarcoma

Answer 16

Most common

Predilection site: right atrial appendage and right atrium

GSDs and Golden retrievers

High rate of metastasis (sleen/liver common)

Rapid recurrence following pericardiocentesis

Grave prognosis

Surgical excision rarely feasible, chemotherapy not generally advised

Question 17

Pericardial effusion caused by chemodectomas (heart base tumour)

Answer 17

Second most common

Arise from chemoreceptors in the pulmonary artery and ascending aorta

Predisposed: brachycephalics, older dogs

Benign, typically slow growing with slow metastatic rate - but can be locally invasive

Clinical signs due to compression of the great vessels

Pericardiectomy can prolong survival with good QOL

Question 18

Pericardial effusion caused by mesothelioma

Answer 18

Low-grade malignancy originating from mesothelial cells lining coelomic cavities

Malignanacy uncommon in dogs

Predilection site: pleura +/- pericardium

Often large volume pericardial effusion

Pericardiectomy palliative

Intracavity chemo an option

Question 19

Paragangliomas

Answer 19

Another form of aortic body tumour

Functional - secrete catecholamines

Question 20

Idiopathic pericardial effusion

Answer 20

Diagnosis of exclusion - neoplasia more common in older dog

Second most common cause of pericardial effusion

Unknwon aetiology

Large breeds over-represented

50% recurrence rate - pericardiectomy is indicated

Pericardial fibrosis with a mixed inflammatory response and no vasculitis

Question 21

Left atrial rupture

Answer 21

Rare

Typically older, small breed dogs

Secondary to severe myxamatosus mitral valve associated with severe left atrial dilation and jet lesions

Guarded prognosis

Question 22

Right-sided congestive heart failure

Answer 22

CHF is most common cause of pericardial effusion in cats

Effusion occurs due to passive congestion and decreased drainage

It rarely results in a volume large enough to cause tamponade

Treatment: CHF therapy

Guarded prognosis

Question 23

Septic pericardial effusions

Answer 23

Rare

May be associated with penetrating or migrating foreign bodies

Cytology and culture and sensitivity

Aggressive antibiosis, exploratory thoracotomy often required

FIP in cats

Clinical signs usually associated with cardiac tamponade

Question 24

Constrictive pericarditis

Answer 24

Uncommon

Thickened, fibrotic pericardium

Can be idiopathic, neoplastic or occur secondary to recurrent pericardial effusions

Signs of right sided heart failure

Pericardiectomy required

Guarded prognosis

Question 25

Cardiac tamponade

Answer 25

Once intrapericardial pressures exceed right atrial, and subsequently right ventricular, pressures, this results in diastolic collapse of the right atrium +/- ventricle Impedes ventricular filling and so reduced stroke volume and cardiac output

Question 26

Pulsus paradox

Answer 26

During pericardial effusion Increase in right ventricular filling on inspiration causing the interventricular septum to shift toward left ventricle (reducing stroke volume) Variation in pulses quality with the respiratory cycle

Question 27

Signalment and history of a patient with pericardial effusion

Answer 27

Often large breed, older dogs Collapse Exercise intolerance Lethargy Abdominal distension Cough Polydipsia Hyporexia Acute pericardial effusion is more likely to result in signs of reduced cardiac output while chronic effusions are more likely to present with signs of right sided congestive heart failure (ascites)

Question 28

Clinical examination of pericardial effusion

Answer 28

Muffled heart sounds Weak femoral pulse, pulses paradoxus Tachycardia Ascites Jugular distension Positive hepatojugular reflux Hepatomegaly/splenomegaly +/- respiratory signs

Question 29

Diagnostics of pericardial effusion

Answer 29

Echocardiography Blood pressure ECG Radiography Clinical pathology Pericardial fluid analysis

Question 30

Echocardiography of pericardial effusion

Answer 30

Best non-invasive method Easy to identify (hypoechoic fluid, contained within bright hyperechoic pericardium) Also look for pleural effusion and ascites Ideally do a thorough search for a cardiac or heart base mass

Question 31

Blood pressure - pericardial effusion

Answer 31

Assess degree of haemodynamic compromise. Hypotension with forward failure

Question 32

ECG - pericardial effusion

Answer 32

Often sinus tachycardia Electrical alternans a common finding

Question 33

Radiography of pericardial effusion

Answer 33

Inferior to thoracic ultrasound Globoid, enlarged cardiac silhouette with very distinct margins Dilated CdVC Abdominal effusion Small pulmonary vessels Clear lung fields

Question 34

Clin path of pericardial effusion

Answer 34

Pre-renal azotaemia common finding Mildly elevated liver enzymes Albumin may be low Anaemia Cardiac troponin I often elevated

Question 35

Pericardial fluid analysis

Answer 35

Assess volume, gross appearance PCV Cytology - low diagnostic yield for neoplastic effusions, useful for diagnosis of septic pericarditis C&S if suspicion of septic pericarditis

Question 36

Key treatment points for pericardial effusion

Answer 36

If tamponade is present, pericardiocentesis should be performed (unless left atrial tear) If haemodynamically unstable patients - high rate IV fluids DO NOT give furosemide

Question 37

Pericardiocentesis

Answer 37

Essential if cardiac tamponade Often palliative rather than curative Owner must know that the effusion may recur

Question 38

Patient prep for pericardiocentesis

Answer 38

Mild sedation Sternal or left lateral recumbency Pericardiocentesis performed via the right side to avoid the large coronary artery Place IV catheter and give IVFT if required Connect ECG Aseptic preparation 3rd-8th ICS, ventral half of the right chest

Question 39

Technique for pericardiocentesis

Answer 39

Use US to find best point of entry, or 5-6th ICS at level of costochondral junction Local anaesthetic infiltration Small stab incision through skin Over-needle catheter (14G) approach: - advance catheter over needle and remove needle once in pericardium Modified Seldinger technique: - Advance introducer catherter into pericardium over the needle, withdraw needle, then thread the guidewire through and remove introducer catheter Attach 3-way tap Aspirate fluid, maintain some for analysis Ensure it does not clot Monitor ECG Once fully drained, remove catheter

Question 40

Complications of pericardiocentesis

Answer 40

Haemorrhage and catastrophic bleeding Arrhythmias Pneumothorax Pulmonary oedema

Question 41

Pericardiectomy

Answer 41

If more than 3 pericardiocentesis are required Pericardium should be sent for histopathology Subtotal pericardiectomy preferred to a pericardial window May be curative in cases in cases of idiopathic pericardial effusion but in most cases palliative