20 Pericardium and pericardial pathology Flashcards
Describe the anatomy of the pericardium.
The pericardium is a double layered sac around the heart which is thin and echogenic. The pericardial layers are the outer fibrous pericardium which lines the diaphragm and the inner serous pericardium which lines the great vessels. The inner serous pericardial layers are the parietal layer, which lines the fibrous pericardium, and the visceral layer (epicardium), which lines the outside of the heart. The parietal layer reflects on the great vessels to form the sinuses. The transverse sinus divides the great arteries and the great veins. The oblique sinus is posterior to the heart and offers a space for expansion. The pericardial space is the space between the parietal layer and visceral layer, which holds the pericardial fluid, which is thin and echolucent.
What are the pericardial pathologies.
Pericarditis (inflammation of the pericardium) can cause a pericardial effusion (increased fluid in the pericardium) which can cause cardiac tamponade (decreased CO). Long term pericardial inflammation can cause pericardial thickening and pericardial constriction.
How do patient position and fluid volume affect the location of the pericardial effusion?
If the patient is supine, the pericardial fluid is located posteriorly, and, if the patient is sitting up, the pericardial fluid is located inferiorly.
If the volume is small, the pericardial effusion is localised and dependent on the patient’s position, and, if the volume is large, the pericardial effusion is circumferential and can cause cardiac tamponade.
How is a pericardial effusion differentiated from a pleural effusion?
A pericardial effusion is superior and is located between the LA and the front of the descending aorta and is diagnosed with TTE. A pleural effusion is inferior and is located between the LA and the back of the descending aorta and is diagnosed with a CXR.
A pericardial effusion causes muffled heart sounds but normal breath sounds.
What are the depths and volumes for small, moderate and large pericardial effusions?
A small pericardial effusion has a depth of 0.5-1.0cm and a volume of 100-250ml.
A moderate pericardial effusion has a depth of 1.0-2.0cm and a volume of 250-500ml.
A large pericardial effusion has a depth of >2.0cm and a volume of >500ml.
What are the causes of pericardial effusions?
Idiopathic, infection (bacterial or viral), inflammation (Dressler’s syndrome post-MI, uraemia secondary to renal failure, collagen vascular diseases (e.g. RA or SLE), post-cardiac surgery or post-radiotherapy), injury (chest trauma, post-cardiac surgery, aortic dissection) and malignant tumours (primary or secondary).
When is a pericardiocentesis and a pericardiectomy indicated?
Cardiac tamponade, suspected purulent or tuberculous effusions, and/or effusions measuring >2.0cm during diastole.
Permanent pericardial constriction.
What may be present within pericardial effusions?
Fluid, blood or pus and/or strands of fibrin or masses.
What are the echo characteristics of cardiac tamponade?
RA and/or RV collapse during diastole, IVC dilatation (>2.1cm) with decreased inspiratory collapse (<50%), and increased respiratory variation in AV valve E wave velocities (TV E wave variation >25% and MV E wave variation >15%).
Why do pericardial effusions cause the echo characteristics of cardiac tamponade?
The pericardial effusions compress the RA (RA collapse). This increases the RA pressure which increases the systemic venous pressure (IVC dilatation). This increases the RV pressure which shifts the IVS towards the LV which decreases LV filling. This increases the respiratory variation.
What are the symptoms and signs of cardiac tamponade?
Dyspnoea (with normal lungs), tachycardia (>100bpm), hypotension (<100mmHg), pulsus paradoxus (>10mmHg decrease in SBP during inspiration), elevated JVP and/or quiet heart sounds.
What is cardiac tamponade?
The haemodynamic decompensation which is present when the pericardial effusion compresses the heart.
What is pericardial constriction?
In pericardial constriction, the serous pericardium is thickened and fibrosed so it constricts the heart and decreases ventricular filling during diastole.
In pericardial constriction, the heart is within a rigid shell so the ventricles are interdependent.
What are the symptoms and signs of pericardial constriction?
Dyspnoea, fatigue and/or abdominal discomfort/swelling.
Elevated JVP, increase in JVP on inspiration, hypotension with low pulse pressure, quiet heart sounds, pleural effusions, hepatomegaly, ascites, peripheral oedema and/or muscle wasting.
What are the echo characteristics of pericardial constriction?
Fibrosed and calcified and thickened and echogenic pericardium.
Diastolic dysfunction with increase MV and TV E wave velocities (E/A >1) and decreased E wave deceleration times (DT <160ms).
Increased respiratory variation (TV and MV E wave variation >25%).
Bi-atrial dilatation.
Inspiratory IVS bounce (IVS shifts left during inspiration).
IVC dilatation (>2.1cm) with decreased inspiratory collapse (<50%).
