Pericardial disease Flashcards
What is the pericardium?
- sac surrounding the heart
- inner: visceral layer - surface of heart
- outer: parietal layer
- visceral layer = epicardium
- parietal layer contiguous with BV adventitial layer
- sterno-pericardial ligament (attaches it to the sternum)
- phrenic-pericardial ligament (attaches it to the diaphragm)
- prevents distension
Function of the pericardium
- not essential
- fixes the heart anatomically
- reduce friction
- equalises gravitational forces (pericardial fluid)
- prevention of over dilation (pericardial restraint)
- regulation between stroke volumes of both ventricles (ventricular coupling)
What can go wrong with the pericardium?
Pericardial sac can fill with fluid:
- blood
- transudate
- exudate
Mass can be present within the pericardial space, heart or the pericardium:
- neoplasia (haemangiosarcoma, mesothelioma, chemodectoma, mets tumours - thyroid, osteosarcoma, MCT)
- pericardial peritoneal diaphragmatic hernias: cats (often asymptomatic)
- pericardial cysts: congenital
The pericardium can become stiff - ‘constrictive’
Pericardial dz
Impaired ventricular filling as a consequence of increased intrapericardial pressures (not volume)
- fluid accumulation
- presence of a mass
- pericardial constriction
Cardiac tamponade
Constrictive pericardial dz
- restriction of pericardial filling secondary to reduced pericardial compliance
Why does pericardial dz cause cardiac tamponade?
- intrapericardial pressure equilibrates with the right atrial and right ventricular filling pressures
- continuum that ranges from subclinical to fulminant heart failure
- chronic tamponade -> congestive right heart failure
- acute tamponade -> low cardiac output and shock
Pericardial dz - Typical history
Depends on pathophysiology but 2 common types of presentation
1. acute cases
- sudden onset exercise intolerance, weakness, collapse, shock, rapid death if untreated
2. chronic cases - more common
- 2w hx of ascites, progressive exercise intolerance, lethargy, GIT signs, collapse
Pericardial dz - Clinical signs
- jugular distension
- positive hepatojugular reflexes
- ascites
- tachycardia
- muffled heart sounds
- weak femoral pulses
- pale mm
- tachypnoea/dyspnoea
- GIT signs
Why do these cases get tachycardia?
- fall in output = fall in bp = increase in sympathetic activity = tachycardia
Pericardial dz - Clinical presentation
Triad of CS
1. muffled heart sounds
2. right sided heart failure
- ascites
- distended jugular veins
- positive hpeatojugular reflex
3. forward failure
- poor peripheral pulses
Pericardial dz - Diagnosis
Triad of CS
ECG
- tachycardia
- small complexes
- electrical alternans
Echocardiography
- gold standard
- effusion, mass, hernia, cyst
- important to perform echo prior to drainage IF pt stable enough
- ECHO ANY DOG WITH ASCITES
Radiography
- globoid enlargement of the cardiac silhouette with a sharp outline
- herniation of intestinal organs or cystic lesion
What is electrical alternates on ECG?
- QRS size changes regularly from beat to beat
Pericardial dz - tx
- do not give these animals diuretics
– giving diuretics would further reducing circulating volume and make them worse - emergency care
– oxygen
– iv fluid? - pericardiocentesis/pericardial strip
Common causes of pericardial effusion
Transudate/modified transudate
- congenital percardioperitoneal hernia
- right sided congestive heart failure
- hypoalbuminaemia
- idiopathic
Haemorrhage
- LA rupture
- intrapericardial neoplasia
- trauma
- coagulopathy
- benign pericardial haemorrhage
Exudate
- infection
Pericardial dz - acquired disorders
Pericardial effusion in dogs
- cardiac neoplasia (most common): haemangiosarcoma, heart base tumours, mesotheliomas, lymphosarcoma
- idiopathic (haemorrhage)
- LA rupture
- coagulopathies, uremic, infection (bacterial & fungal)
Pericardial effusion in cats
- CHF, FIP
Haemangiosarcomas
- signalment
- where?
- mets?
- presentation
- tx
- older GSF & GRets
- RA / right auricular appendage
- mets is common
– worth scanning the spleen as well - acute tamponade (haemorrhage): can be a small volume if an acute bleed
- can present with forward failure
- surgical resection
Heart base tumours
- what are they?
- signalment
- where?
- mets?
- presentation
- tx
- theory as to why they happen
- chemodectomas
- ectopic thyroid carcinoma
- older brachycephalic
- around the aortic arch
- rarely mets
- chronic tamponade
- present in RHF
- no surgical tx
- often incidental finding in breaches PM: constantly hypoxaemic so receptors in the aortic arch are constantly stimulated
Mesotheliomas
- where do they arise from?
- presentation
- tx
- arise from serous membranes
– pericardium
– pleura
– peritoneum
– tunica vaginalis of the testes - severe pleural & pericardial effusion
- histopathological diagnosis
- chronic tamponade
- present in RHF
- pericardiectomy
Idiopathic pericardial effusion
- aetiology
- signalment
- presentation
- tx
- idiopathic (haemorrhagic)
- large breed dogs (St Bernards, GRets)
- chronic tamponade
- present in RHF
- pericardiocentesis
- pericardiectomy at 3rd recurrent
Left atrial rupture
- what is it secondary to?
- signalment
- presentation
- what to not do
- secondary to CVD (severe MR, jet lesions)
- small breed dogs (CKCS)
- acute tamponade
- presented forward failure
- NO pericardiocentesis
Peritoneal pericardial diaphragmatic hernia
- prevalence
- what is it?
- what is it associated with?
- signalment
- CS
- tx
- most common congenital pericardial dz
- communication between the pericardial and the peritoneal cavities allowing herniation of abdominal contents
- abnormal fusion of the septum transverse with the pleuroperitoneal folds / post natal injuries
- associated to umbilical hernias or abnormal sternebrae
- Weimaraners & Persian
- CS vary with the herniated structures and the onset ranges from 4w-15y
- incidental finding
- surgical correction
Pericardiocentesis
- use
- how to
- therapeutic & diagnostic
- L lateral recumbency
– avoids laceration of main coronary vessels
– the R side has a larger cardiac notch - between the 4th & 6th ICS at the level of the costochondral junction (elbow crosses the costochondral junction)
- sedation? fluid therapy? ECG monitor
- surgical prep & LA
- stab incision
- 5 inch catheter
- advance until feel scratch/pop
- check if clots: if in the right place the needle hub shouldn’t clot
- several different catheter types can be used
Pericardiocentesis
- is it safe?
- complications
Safe procedure
- risk inversely related to the amount of effusion
Complications
- cardiac puncture
- arrhythmias
- dissemination of infection or neoplasia
- atrial fibrillation
- myocardial stunning
