STEMI

Question 1

What does STEMI stand for?

Answer 1

ST - segment elevation myocardial infarction.

Question 2

What is a STEMI also known as?

Answer 2

A heart attack.

Question 3

What is the epidemiology of a STEMI?

Answer 3

· More common in men than women.
· Tends to occur at a younger age in men.
· Incidence in women increases after the menopause.

Question 4

What is the pathophysiology of a STEMI?

Answer 4

· Plaques begin with LDL and saturated fat accumulation in the intima.
· Leukocytes adhere to the endothelium, enter the intima and become foam cells.
· Followed by the adhesion of leukocytes t the endothelium, then diapedesis and entry into intima where they accumulate lipids and become foam cells – rich source of proinflammaotry mediators&raquo_space;> FATTY STREAK
· Plaques can form calcifications as they grow.
· Eventually, stenosis can limit blood flow under conditions of increased demand, causing angina.
· STEMI occurs after abrupt disruption of a cholesterol-laden plaque.
· The substances are exposed, promoting platelet aggregation, thrombin, and thrombus generation.
· When coronary artery blood flow is interrupted, the zone of myocardium supplied loses its ability to perform contractile work.
· Necrotic myocytes slip past each other and lead to infarction expansion.

Question 5

What does the prognosis depend on?

Answer 5

· Time to presentation after onset of chest pain.

· Time to treatment after presentation.

Question 6

What is prognosis improved by?

Answer 6

Early reperfusion, adherence to medical therapy and risk factor modification.

Question 7

What is the aetiology of a STEMI?

Answer 7

· Consequence of CAD - atherosclerosis with plaque fissuring or rupture and thrombus formation.

· A small proportion are caused by a coronary spasm, following chest trauma or spontaneous coronary/aortic dissection.

Question 8

List the risk factors that might cause a STEMI?

Answer 8

· Smoking. 
· HTN (hypertension)
· Diabetes. 
· Obesity.
· Metabolic syndrome. 
· Physical inactivity.
· Dyslipidaemia. 
· Renal insufficiency.
· Established CAD. 
· FH of premature CAD.

Question 9

What are the common signs and symptoms of a STEMI?

Answer 9

· Chest pain. 
· Dyspnoea. 
· Diaphoresis. 
· Nausea and vomiting. 
· Dizziness.
· Distressed. 
· Tachycardia.

Question 10

Describe the typical presenting chest pain.

Answer 10

Diffuse, severe pain, at rest or on exertion, heavy in nature, central with radiation to left arm or jaw, and lasts for at least 20 minutes.

Question 11

What is dyspnoea usually due to?

Answer 11

Due to pulmonary congestion from diastolic dysfunction.

Question 12

What is pallor usually due to?

Answer 12

High sympathetic output.

Question 13

What are the features of cardiogenic shock?

Answer 13

Reduced consciousness, profound hypotension, acute shortness of breath and imminent cardiac arrest.

Question 14

What investigations would you request if you suspected a patient had a STEMI?

Answer 14

· ECG. 
· Cardiac biomarkers. 
· Glucose. 
· U&E's. 
· Serum lipids. 
· CXR.
· Coronary angiogram.
· ECHO.

Question 15

What would a typical STEMI ECG show?

Answer 15

ST-elevation in 2 or more leads.

Question 16

What would cardiac biomarkers typically show?

Answer 16

Elevated troponin.

Question 17

Why is the patient’s glucose level measured?

Answer 17

Because hyperglycaemia is common in acute MI, with or without diabetes.

Question 18

Why might a coronary angiogram be performed?

Answer 18

To show the presence of a thrombus with occlusion of artery.

Question 19

When and why might an ECHO be performed?

Answer 19

After reperfusion therapy to assess left ventricular function.

Question 20

List potential differentials.

Answer 20

· Unstable angina. 
· NSTEMI.
· Aortic dissection.
· PE.
· Pneumothorax.
· Pneumonia.
· Pericarditis.
· Myocarditis.
· GORD.
· Oesophageal spasm.
· Costochondritis.
· Anxiety.

Question 21

How would you treat a suspected MI?

Answer 21

· 1st - Aspirin.
· Adjunct - Oxygen.
· Plus - Morphine.
· Adjunct - GTN.

Question 22

How would you treat a harm-dynamically unstable patient?

Answer 22

· 1st - Emergency revascularisation (PCI or CABG).
· Plus - Anti-coagulation.
· Plus - Aspirin.
· Plus - Morphine.
· Adjunct - Oxygen. 
· Adjunct - Inotrope support.

Question 23

What does CABG stand for?

Answer 23

Coronary artery bypass graft

Question 24

What does an inotrope agent do?

Answer 24

Alters the force or energy of muscular contractions.

Question 25

List the complications that can arise.

Answer 25

· Congestive heart failure. 
· Sinus bradycardia, first degree heart block and type I second degree heart block. 
· Recurrent chest pain. 
· Post-infarction pericarditis (Dressler's syndrome). 
· Ventricular arrhythmia's. 
· Recurrent ischaemia and infarction.
· Depression.
· In-stent thrombosis.