acute coronary syndrome

Question 1

what does acute coronary syndrome include

Answer 1

Umbrella term that includes:

1. ST-elevation myocardial infarction
2. Unstable angina
3. Non-ST-elevation myocardia infarction

Question 2

what is normal troponin an indication of

Answer 2

unstable angina

Question 3

what is high troponin an indication of

Answer 3

NSTEMI

Question 4

define unstable angina

Answer 4

A new onset of angina or deterioration in previously diagnosed stable angina.

Chest pain that occurs at rest, is not relieved by GTN and occurs more frequently and lasts for longer.

Question 5

what does unstable angina require

Answer 5

usually requires immediate admission or referral to hospital

Question 6

what is STEMI

Answer 6

Complete occlusion of a MAJOR coronary artery

This leads to full thickness damage of heart muscle

Question 7

how is STEMI diagnosed

Answer 7

Diagnosed on ECG at presentation

Question 8

what is NSTEMI

Answer 8

Partial occlusion of a MAJOR coronary artery or complete occlusion of a MINOR coronary artery
Causes partial thickness damage of the heart

Question 9

how is NSTEMI diagnosed

Answer 9

Diagnosis made on troponin results

Question 10

what may NSTEMI ECG show

Answer 10

ECG may show ST-depression and/or T wave inversion

Question 11

pathology of acute coronary syndromes

Answer 11

1. Rupture or erosion of the fibrous cap of a coronary artery atheromatous plaque
2. Subsequent formation of a platelet-rich clot (thrombosis), inflammation and vasoconstriction produced by platelet release of serotonin and thromboxane A2

Question 12

how does unstable angina differ to NSTEMI

Answer 12

in NSTEMIs the occluding thrombus is sufficient to cause myocardial damage and an elevation in serum markers of myocardial injury (troponin and creatine kinase)

Question 13

do acute coronary syndromes always present with ST elevation

Answer 13

NO

Question 14

ECG changes in unstable angina

Answer 14

normal or T wave depression

Question 15

ECG changes in STEMI

Answer 15

1. ST elevation and tall T waves
2. Will produce pathological Q waves sometime after an MI
3. There may be a new LBBB in larger MIs (WiLLiaM)
   V1 – W shape
   V6 – M shape

Question 16

ECG changes in NSTEMI

Answer 16

A retrospective diagnosis

Will see ST depression and/or T wave inversion

Question 17

ECG changes in infarction

Answer 17

ST depression

T wave flattening or inversion

Question 18

what are Q waves evidence of

Answer 18

previous infarction

Question 19

how do pathological Q waves differ to normal ones

Answer 19

are deeper and wider than normal (>35% QRS height and wider than one small square)

The larger the infarction is, the more likely it will result in pathological Q waves

Question 20

what would a posterior STEMI ECG show

Answer 20

will show ST depression in V1 to V4 as the view of the heart on the ECG is inverted.

V7-V9 are additional leads that can be placed on someone’s back to check for a posterior MI

Question 21

main cause of acute coronary syndrome

Answer 21

Rupture of atherosclerotic plaque and consequent arterial thrombosis

Question 22

other causes of acute coronary syndromes

Answer 22

1. coronary vasospasm without plaque rupture
2. drug abuse (amphetamines, cocaine)
3. dissection of the coronary artery related to defects of the vessel connective tissue
4. thoracic aortic dissection

Question 23

investigations for acute coronary syndromes

Answer 23

1. ECG
2. Bloods
3. cardiac enzymes
4. CT angiography

Question 24

which blood tests to do for ACS (4)

Answer 24

FBC
U&E
Glucose
Lipids

Question 25

what do cardiac enzymes do

Answer 25

released into blood stream when cardiac muscle is damaged

Question 26

3 examples of cardiac enzymes

Answer 26

1. Troponin T and I 2. creatine kinase 3. myoglobin

Question 27

describe troponin T and I

Answer 27

highly sensitive and specific markers of cardiac muscle injury but not diagnostic Rise within 3-12 hours Peak at 24-48 hours Return to baseline by 5-14 days

Question 28

diagnostic criteria for troponin T and I

Answer 28

<14g/l normal = no MI 14-30 ng/l = possible MI >30ng/l = definite MI

Question 29

what does creatine kinase do

Answer 29

catalyses conversion of creatine and utilises ATP to create phosphocreatine (PCr) and ADP

Question 30

3 types of creatine kinase

Answer 30

1. CK-MM 2. CK-BB 3. CK-MB

Question 31

where is CK-MM found

Answer 31

mainly in skeletal muscle

Question 32

where is CK-BB found

Answer 32

predominantly in the brain

Question 33

where is CK-MB found

Answer 33

predominantly in the heart highly specific and sensitive, will peak earlier if reperfusion occurs

Question 34

how is CK-MB used to determine infarction

Answer 34

CK-MB rise within 3-12 hours of onset of pain and can be used to determine re-infarction as levels drop back to normal after 36-72 hours

Question 35

what do myoglobins do

Answer 35

Rises within 1-4 hours of onset of pain Highly sensitive but not specific

Question 36

2 types of causes for raised troponin

Answer 36

1. cardiac causes 2. non cardiac causes

Question 37

5 cardiac causes for raised troponin

Answer 37

1. Congestive heart failure 2. Acute or chronic stable coronary artery disease 3. Myocarditis (and endocarditis and pericarditis) 4. Tachy/bradyarrhythmia’s 5. Heart block

Question 38

8 non cardiac causes for raised tropnin

Answer 38

1. PE 2. Gram negative sepsis 3. Severe pulmonary hypertension 4. Renal failure 5. COPD 6. Diabetes 7. Drugs 8. Acute neurological events

Question 39

3 things to classify unstable angina

Answer 39

1. cardiac chest pain at rest 2. May have crescendo pattern (it gets worse and worse more readily) 3. New onset angina

Question 40

what happens to untreated unstable angina

Answer 40

50% of patients with unstable angina will get an infarction within 30 days if left untreated

Question 41

diagnosis and investigations for unstable angina

Answer 41

History FBC – anaemia aggravates it Cardiac enzymes (troponin normal) – excludes infarction ECG – ST depression when patient is in pain CT Coronary angiography Risk assessment (QRISK2) – if low risk do an elective stress test

Question 42

management options for unstable angina

Answer 42

1. risk factor modification 2. PCI & CABG 3. anti platelet therapy 4. anti coagulants 5. nitrates 6. beta blockers 7. statins 8. ACE inhibitors 9. calcium channel blockers

Question 43

4 risk factor modifications for unstable angina

Answer 43

Stop smoking Lose weight Healthy diet Exercise

Question 44

3 examples of anti coagulants

Answer 44

1. heparin 2. enoxaparin - LMWH 3. Fondaparinux

Question 45

what does heparin do

Answer 45

interferes with thrombus formation at site of plaque rupture by inhibiting factors II (prothrombin), VII, IX and X and reduces risk of ischaemic events and death

Question 46

why is enoxaparin better than heparin

Answer 46

enoxaparin has better efficacy than unfractionated heparin

Question 47

what does Fondaparinux do

Answer 47

synthetic polysaccharide) inhibits factor Xa of the coagulation cascade and has a lower risk of bleeding than heparin

Question 48

differences between the 3 conditions

Answer 48

NSTEMI and unstable angina have similar management, only difference is that an NSTEMI is an acute infarction and will not involve the whole of the heart wall like a STEMI. Both are due to a narrowing of the coronary artery lumen rather than a total occlusion like a STEMI

Question 49

complications of CS (DARTH VADER)

Answer 49

Death Arrhythmias Ruptured septum Tamponade HF Valve disease Aneurysm of ventricle Dressler’s syndrome – pericarditis and pericardial effusion after 2-12 weeks Embolism Reoccurrence of ACS