Chapter 4 - cardiac causes of cardiac arrest

Question 1

what are the 3 types of ACS?

Answer 1

STEMI
NSTEMI
Unstable angina

Question 2

what is the definition of ACS?

Answer 2

group of clinical syndromes that cause chest pain/discomfort, resulting from myocardial ischaemia

Question 3

what causes ACS? (pathophysiology)

Answer 3

Originally from coronary artery disease, initiated by rupture of an atherosclerotic plaque within a coronary artery. This causes acute thrombosis within the vessel lumen often with haemorrhagic extension into the atherosclerotic plaque. This eventually causes partial or complete obstruction of the lumen, causing sudden loss of blood flow to the coronary artery.

Question 4

Typical symptoms of angina?

Answer 4

chest tightness
pain in jaw/neck
radiates left arm
worse on exertion, relieved by rest

Question 5

Atypical symptoms of angina/MI?

Answer 5

pain radiating to the neck, both arms, abdomen

breathlessness

Question 6

what is the criteria for unstable angina?

Answer 6

1) angina on exertion, which is occuring in increasing frequency over several days due to less and less exertion (i.e. crescendo)
2) angina pain occuring randomly not due to exercise - relieved by GTN
3) prolonged period of pain, but without ECG/trop changes

Question 7

what is the most reliable way of differentiating between angina and MI?

Answer 7

trop

Question 8

typical symptoms of MI?

Answer 8

chest pain and tightness radiating to left jaw and left arm, or both arms and abdomen 
sweating 
nausea/vomiting 
beltching 
lasting 20mins 

however - MI can be silent or atypical symptoms such as breathlessness

Question 9

Criteria for diagnosis of STEMI?

Answer 9

History of sustained chest pain
ECG changes of STEMI or new LBBB
troponin rise - however not needed to initiate treatment

Question 10

What are the lateral leads?

Answer 10

I, aVL, v6

Question 11

what vessel causes an infarct in the lateral leads?

Answer 11

circumflex artery

Question 12

what are the anterior leads?

Answer 12

V2, V3, V4

Question 13

what vessel causes infarct in the anterior leads?

Answer 13

LAD

Question 14

what are the inferior leads?

Answer 14

II, III, aVF

Question 15

what vessel causes infarct in the inferior leads?

Answer 15

right coronary artery

less commonly circumflex

Question 16

What ECG changes indicate a posterior infarct?

Answer 16

reciprocal ST segment depression in anterior chest leads

Question 17

how can you confirm a posterior infarct?

Answer 17

repeat the ECG using posterior leads -V8, V9, V10 placed in horizontal line across the chest

Question 18

what conditions may also cause ECG abnormalities that replicate STEMI?

Answer 18

subarachnoid haemorrhage, TBI, PE, brugada syndrome, takutsobu

Question 19

what score indicates risk of further MI/complications?

Answer 19

GRACE score

Question 20

what does GRACE score stand for?

Answer 20

Global Registry of Acute Coronary Events

Question 21

what does the GRACE score take into consideration?

Answer 21

age
signs of HF
HR at presentation 
BP at presentation
serum creatinine concentration 
ECG changes
troponin concentration 
cardiac arrest at presentation

Question 22

what is the initial management of ACS generally?

Answer 22

aspirin 300mg 
clopidogrel 300mg 
GTN 
O2 if hypoxic 
Morphine IV pain relief

Question 23

what is the management of STEMI specifically?

Answer 23

CORONARY REPERFUSION!!

PPCI
Fibrinolytic therapy

Question 24

how quickly should PPCI be done?

Answer 24

Generally within 12 hrs of symptoms

Hospitals should aim for <120 mins of call to balloon time

Question 25

what medications are given alongside PPCI for maximum effect?

Answer 25

clopidogrel 600mg OR ticagrelor 180mg OR prasugrel 60mg (if not <75yrs, <60kg, history of bleeding or stroke) unfractionated or LWMH

Question 26

What is the benefit of fibrinolytic therapy?

Answer 26

does not need to be delivered in cardiac catheter laboratory or skilled angioplasty team

Question 27

contraindications for fibrinolytic therapy?

Answer 27

``` previous haemorrhagic stroke ischaemic stroke in last 6 months CNS damage recent surgery active bleeding known or suspected aortic dissection known bleeding disorder ```

Question 28

what is given alongside fibrinolytic therapy?

Answer 28

aspirin 300mg ticagrelor 180mg LMWH

Question 29

what should be done for patients who have undergone unsuccesful fibrinolytic therapy?

Answer 29

transfer for urgent rescue PCI

Question 30

management of NSTEMI?

Answer 30

``` fondaparinux 2.5mg OD aspirin 75mg OD clopidogrel 75mg OD OR ticagrelor 90mg OD start BB consider ACE-I statin GTN stop smoking diuretics if HF manage HTN plan for angio ```

Question 31

management of arrest in cath lab?

Answer 31

if VF/VT- 3 stacked shocks should be attempted. If ROSC not achieved - follow ALS guidelines.

Question 32

management of acute cardiogenic shock?

Answer 32

inotropes insertion of intra-aortic balloon pump I+V

Question 33

what are some causes of sudden cardiac death?

Answer 33

``` long QT syndrome brugada syndrome short QT syndrome hypertrophic cardiomyopathy WPW syndrome severe AS dilated cardiomyopathy ```

Question 34

what is the process following sudden cardiac death?

Answer 34

autopsy -> molecular autopsy -> if no cause found then termed "sudden arrhythmic death syndrome"

Question 35

indicator or risk of sudden cardiac death?

Answer 35

regular syncope, particularly during exertion