Cardiac Arrest

Question 1

Which 3 arteries may be blocked in MI

Answer 1

LAD (most likely), then Right coronary artery (2nd most common), then left circumflex

Question 2

The first area of infarction is the subendocardium (inner 1/3rd of endocardium). How does this look on an ECG

Answer 2

ST segment depression (i.e. no ST elevation).

aka subendocardial infarction is an NSTEMI

Question 3

After 3-6 hours of infarction, the full thickness of the endocardium becomes ishcaemic and necroses. This is called a transmural infarct. How does it present on an ECG

Answer 3

Transmural infarct = ST segment rise (STEMI)

Question 4

How can lab diagnostics be used for MIs

Answer 4

Troponin I/T rises and peaks at 48 hours.

CKMB rises and peaks after 24 hours - useful to tell if second infarction has occurred

Question 5

What are the complications of MIs

Answer 5

1. Arrhythmias
2. Cardiogenic shock
3. Pericarditis
4. Myocardial rupture
5. Heart failure

Question 6

What treatment is given for MI

Answer 6

1. Fibrinolytic therapy immediately. Other treatments include anti platelets, anticoagulants, nitrates, beta blockers, pain medications, statins
2. Angioplasty
3. PCI

Watch out for reperfusion injury though