STEMI Assessment

Question 0

Acute Coronary Syndrome

Answer 0

Development of thrombus at site of atherosclerotic plaque disruption within wall of coronary artery
Disruption can manifest as superficial erosion of the endothelium over fibrous cap or acute deep plaque rupture

Question 1

Transmural infarct pathophysiology

Answer 1

Ischaemic necrosis involves full or nearly full thickness of ventricular wall - in distribution of single coronary artery
Usually associated with atherosclerosis, plaque rupture, super-imposed atherosclerosis

Question 2

Following plaque disruption…

Answer 2

Thrombosis! Results from
Adherence, aggregation, activation of platelets
Thrombin and fibrin production via coagulation cascade/platelet activation
Vasoactive molecules released from platelets cause vasoconstriction

Question 3

STEMI & NSTEMI

Answer 3

STEMI - ST elevation is marker if complete coronary occlusion
NSTEMI - incomplete occlusion, ST depression, variable t-wave abnormalities

Question 4

NSTEMI interventions

Answer 4

Restore vessel patency
- mechanical intervention, thrombolysis
Reverse/prevent thrombosis
- anti platelet, heparin, GPIIbIIIa antagonists
Reduce myocardial oxygen demand
 - B blockers, nitrates

Question 5

ACS immediate assessment

Answer 5

ECG, history, examination
And
Risk stratification, blood marker tests inc troponin I

Question 6

ECG in ACS

Answer 6

Record immediately! Especially if still in pain
If normal or non-diagnostic ECG with continuing pain, repeat after 10-30 min
If pain resolves repeat after 1-2 hours - changes can appear late
Repeat ECG if chest pain repeats or recurs

Question 7

ECG STEMI diagnosis

Answer 7

> 1mm in contiguous limb leads
2mm in contiguous precordial leads
Or
New left bundle brand block

Question 8

Left bundle branch block criteria

Answer 8

QRS duration >120ms (3 small squares)

Broad, notched or slurred R wave in I, aVL, V5&6

Question 9

Non- MI causes ST elevation

Answer 9

Acute pericarditis
Myocarditis
Massive PE (V1-2)
Hyperkalaemia (1-2)
Hypothermia
Hypercalcaemia

Question 10

True posterior MI criteria

Answer 10

ST elevation in posterior leads
Reciprocal ST-depression in V1-3
Component of inferior ischaemia
Often occurs with inferior MI (LCx territory)

Question 11

MI presenting symptoms

Answer 11

Central pain/discomfort lasting more than a few minutes
Radiating to other areas eg arms, jaw, neck, back
Collapse

Question 12

Elderly/diabetic patients often present with…

Answer 12

Dyspnoea only
Tachycardia/palpitations
Nausea/vomiting

Question 13

Complications of acute MI

Answer 13

Ischaemic - angina, reinfarction, infarct extension
Mechanical - HF, cardiogenic shock, aneurysms, cardiac rupture
Arrhythmic
Embolism - CNS or periphery
Inflammatory - pericarditis

Question 14

Cardiac rupture

Answer 14

Complication of acute MI - 1-5% cases
Due to weakening of necrotic / inflamed myocardium
Commonest 4-7 days post-infarct