STEMI Flashcards
What does STEMI stand for?
ST - segment elevation myocardial infarction.
What is a STEMI also known as?
A heart attack.
What is the epidemiology of a STEMI?
· More common in men than women.
· Tends to occur at a younger age in men.
· Incidence in women increases after the menopause.
What is the pathophysiology of a STEMI?
· 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»_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.
What does the prognosis depend on?
· Time to presentation after onset of chest pain.
· Time to treatment after presentation.
What is prognosis improved by?
Early reperfusion, adherence to medical therapy and risk factor modification.
What is the aetiology of a STEMI?
· 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.
List the risk factors that might cause a STEMI?
· Smoking. · HTN (hypertension) · Diabetes. · Obesity. · Metabolic syndrome. · Physical inactivity. · Dyslipidaemia. · Renal insufficiency. · Established CAD. · FH of premature CAD.
What are the common signs and symptoms of a STEMI?
· Chest pain. · Dyspnoea. · Diaphoresis. · Nausea and vomiting. · Dizziness. · Distressed. · Tachycardia.
Describe the typical presenting chest pain.
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.
What is dyspnoea usually due to?
Due to pulmonary congestion from diastolic dysfunction.
What is pallor usually due to?
High sympathetic output.
What are the features of cardiogenic shock?
Reduced consciousness, profound hypotension, acute shortness of breath and imminent cardiac arrest.
What investigations would you request if you suspected a patient had a STEMI?
· ECG. · Cardiac biomarkers. · Glucose. · U&E's. · Serum lipids. · CXR. · Coronary angiogram. · ECHO.
What would a typical STEMI ECG show?
ST-elevation in 2 or more leads.
What would cardiac biomarkers typically show?
Elevated troponin.
Why is the patient’s glucose level measured?
Because hyperglycaemia is common in acute MI, with or without diabetes.
Why might a coronary angiogram be performed?
To show the presence of a thrombus with occlusion of artery.
When and why might an ECHO be performed?
After reperfusion therapy to assess left ventricular function.
List potential differentials.
· Unstable angina. · NSTEMI. · Aortic dissection. · PE. · Pneumothorax. · Pneumonia. · Pericarditis. · Myocarditis. · GORD. · Oesophageal spasm. · Costochondritis. · Anxiety.
How would you treat a suspected MI?
· 1st - Aspirin.
· Adjunct - Oxygen.
· Plus - Morphine.
· Adjunct - GTN.
How would you treat a harm-dynamically unstable patient?
· 1st - Emergency revascularisation (PCI or CABG). · Plus - Anti-coagulation. · Plus - Aspirin. · Plus - Morphine. · Adjunct - Oxygen. · Adjunct - Inotrope support.
What does CABG stand for?
Coronary artery bypass graft
What does an inotrope agent do?
Alters the force or energy of muscular contractions.
List the complications that can arise.
· 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.
