Myocarditis + Pericardial disease

Question 1

What is myocarditis?

Answer 1

inflammation of the myocardium

Question 2

Causes of myocarditis

Answer 2

external triggers:
- infection (mostly viral)
- drugs/toxins (eg. alcohol)

internal triggers (immune-mediated):
- hypersensitivity reaction to vaccines
- autoimmune diseases

Question 3

3 main clinical presentations of myocarditis

Answer 3

chest pain (can mimic MI)
arrhythmias (AV block, ventricular arrhythmias)
heart failure (acute or chronic)

Question 4

Describe the layers of the pericardium

Answer 4

2 layered sac that encircles the heart

tough outer fibrous layer (parietal pericardium)
inner serosal layer (visceral pericardium)

potential space with <50ml fluid between layers

Question 5

What does the pericardium do?

Answer 5

anchors the heart in the thorax
acts as a barrier to infection
limits sudden dilatation of the heart

[however it is not essential for life]

Question 6

Causes of pericardial disease

Answer 6

idiopathic
infectious - viral, TB, bacteria
non-infectious - autoimmune (eg. Dressler’s syndrome), cancer, metabolic (eg. renal failure), trauma (iatrogenic or direct chest trauma), radiation, drugs

Question 7

What 3 things could go wrong with the pericardium and how can they be treated?

Answer 7

effusion - fluid in pericardial space - drain

pericarditis - inflammation - anti-inflammatories

constriction - fibrosis - surgery

Question 8

What is the most common cause of acute pericarditis?

Answer 8

viral/idiopathic

Question 9

Pericarditis symptoms

Answer 9

chest pain worse on breathing in and lying down (increases venous return to heart, stretches heart and therefore stretches pericardium)

pericardial rub can be present (due to movement of inflamed pericardial layers against one another)

Question 10

How is acute pericarditis treated?

Answer 10

NSAIDs and Colchicine

colchicine = has anti-inflammatory properties and reduces recurrence rate after initial episode

Question 11

Describe ECG changes in acute pericarditis

Answer 11

ST elevation - saddle-shaped and widespread

[whereas an MI would be dome-shaped and regional]

Question 12

What is cardiac tamponade?

Answer 12

when a pericardial effusion compresses the cardiac chambers and limits filling of the heart

Question 13

Causes of cardiac tamponade

Answer 13

neoplastic
postviral
uraemic
traumatic

Question 14

Which 2 factors determine the effect of a pericardial effusion on the heart?

Answer 14

how much fluid is present (more fluid = more effect)

how quickly the fluid accumulates (quicker = more effect as heart doesn’t have time to adapt)

Question 15

What can happen to QRS complexes in large pericardial effusions?

Answer 15

small and vary in height from beat to beat
due to heart swinging within the effusion
causes electrical axis to constantly change

Question 16

Clinical features of cardiac tamponade (‘tamponade quadrad’)

Answer 16

hypotension (interferes with heart filling, decreased preload, decreased stroke volume, decreased cardiac output)

tachycardia (compensatory mechanism to try and preserve cardiac output)

raised JVP

pulsus paradoxus (decrease in systolic BP >10mmHg during inspiration)

Question 17

What is pulsus paradoxus?

Answer 17

decrease in systolic BP >10mmHg during inspiration)

Question 18

How is cardiac tamponade treated?

Answer 18

pericardiocentesis

Question 19

What causes constrictive pericarditis?

Answer 19

thickened scarred pericardium forms a rigid shell around heart –> inhibits normal filling of chambers
most commonly idiopathic

Question 20

Clinical features of constrictive pericarditis and reasons why these occur

Answer 20

increased systemic venous pressure:
- raised JVP
- distended neck veins
- hepatomegaly
- ascites
- peripheral oedema

low cardiac output:
- fatigue
- low blood pressure

other features:
- Kussmaul’s sign (raised JVP on inspiration)
- pericardial knock (early diastolic sound)

Question 21

Constrictive pericarditis treatment

Answer 21

surgical removal of pericardium