Myocardial Infarction

Question 1

List symptoms of MI?

Answer 1

• sweaty/clammy
• SOB
• jaw pain
• chest pain
• back pain

Question 2

List signs of MI?

Answer 2

• tachycardia >100bpm
• distress
• HF (crackles, raised JVP)
• shock
• arrhythmia

Question 3

Why is troponin measured to check for MI?

Answer 3

Part of the cardiac myocyte which is released to the bloodstream.
It is a marker of cardiac necrosis.
High sensitivity so can detect even small MI’s

Question 4

Define an MI?

Answer 4

An elevated troponin in a clinical setting consistent with MI.

Question 5

Explain the types of MI.

Answer 5

1. Spontaneous MI due to a primary coronary event.
2. Increased O2 demand or decreased O2 supply. e.g HF, sepsis, anaemia, hypertension.
3. Sudden cardiac death.
   4a. MI associated with percutaneous coronary intervention.
   4b. MI stent thrombus documented by angiography or PM.
4. MI associated with CABG.

Question 6

List non-coronary causes of MI (type 2)?

Answer 6

• acute congestive HF
• tachy-arrhythmias
• pulmonary embolism
• sepsis
• apical ballooning syndrome

Question 7

What is apical ballooning syndrome?

Answer 7

(takotsubo cardiomyopathy)

- due to stress you get ballooning of the heart apex.

Question 8

What are chronic non-MI causes of elevated troponin?

Answer 8

• renal failure
• chronic HF
• infiltrative cardiomyopathies e.g. amyloidosis, haemochromotosis, sarcoidosis.

Question 9

What is unstable angina?

Answer 9

an acute coronary event without a rise in troponin

- clinical presentation of MI and ECG changes.

Question 10

What is Glagovian remodelling?

Answer 10

When an artery remodels to increase cross-sectional area to accomodate plague without reduction in lumen.

Question 11

How do the coronary arteries differ in NSEMI and STEMI?

Answer 11

NSTEMI: CA is not fully occluded.
STEMI: CA is fully occluded.

Question 12

Describe ECG patterns in a STEMI?

Answer 12

• ST elevation

Question 13

Where would a posterior infarct be seen on ECG?

Answer 13

Wouldnt as no leads here, but can see reciprocal depression in anterior leads? (CHECK THIS)

Question 14

What is the immediate management of a STEMI?

Answer 14

• ABCD
• Take ambulance to cardiac centre
• Have defib attached while in ambo
• Give 300mg of aspirin PO
• Give 5000u of unfractionated heparin
• Morphine 5-10mg IV for pain
• Anti-emetics
• Clopidogrel in ambulance
• Ticagrelor in hospital
• Activate PPCI team

Question 15

Why is PCI better than thrombolysis?

Answer 15

• improves survival
• reduces stroke
• reduces chance of further MI
• reduces change of further angina
• speeds up recovery
• shortens time spent in hospital

Question 16

What care would be given as subsequent management of STEMI?

Answer 16

• Monitor in coronary care unit for complications of MI
• Echocardiogram too look at LV function and cardiac structure
• Cardiac rehabilitation
• Secondary prevention drugs.

Question 17

What drugs can be given for secondary prevention of STEMI?

Answer 17

• ACEi: For all
• B-blockers: For all
• Statins: For all
• Eplerenone: In diabetes, LVSD or HF (K+-sparring diuretic).

Question 18

What complications of MI can occur?

Answer 18

• Arrythmias: VT/VF/AF
• Heart failure
• Cardiogenic shock
• Myocardial rupture:
  
  • Septum - VDS
  • Papillary muscle - mitral regurg.
  • Free wall - tamponade.
• Psychological: Anxiety/depression

Question 19

What is the subsequent management of NSTEMI’s?

Answer 19

• Monitor in coronary care unit for complications.
• aspirin
• clopidegrel/tricagrelor
• LMWH or fondaparinux
• Drugs (same as STEMI).
• Echo
• Cardiac rehabilitation.

Question 20

Describe a ACS risk model?

Answer 20

GRACE model

• Used to calculate risk of ‘in hospital death/MI’ and ‘death in 6 months/MI’
• Based on
  - Age, HR, BP, Creatinine
  - If cardiac arrest at admission
  - If ST segment deviation
  - If elevated cardiac markers
  - CHF (rales and JVD)

If low risk: discharge on medical treatment.
If intermediate risk: discharge to be readmitted for angiogram in 1-2 weeks.
If high risk (GRACE >140): urgent inpatient angiogram.