Acute coronary syndrome presentation and management Flashcards
What is the main cause of myocardial infarction?
MI occurs due to coronary artery occlusion, most often from rupture of an atherosclerotic plaque leading to thrombus formation.
What happens at the cellular level during an MI?
Ischaemia → Lack of oxygen supply.
Myocyte injury → Switch to anaerobic metabolism, ATP depletion.
Myocardial cell necrosis → Irreversible damage if blood flow is not restored.
What are STEMI and NSTEMI?
STEMI (ST-Elevation Myocardial Infarction) → Full-thickness myocardial infarction with ST elevation on ECG.
NSTEMI (Non-ST Elevation Myocardial Infarction) → Partial-thickness infarction with ST depression or T wave inversion.
What are the major risk factors for MI?
Modifiable → Smoking, hypertension, hyperlipidaemia, diabetes, obesity, sedentary lifestyle.
Non-modifiable → Age, male gender, family history of coronary artery disease (CAD).
How has MI epidemiology changed over time?
Overall decline in mortality due to early interventions and prevention.
Increasing incidence in younger adults due to lifestyle factors.
More cases in women and diabetics, often with atypical symptoms.
What are the classic symptoms of MI?
Severe, crushing chest pain → Retrosternal, radiates to jaw, left arm, or back.
Associated symptoms → Sweating, nausea, breathlessness, palpitations.
Pain lasting >20 minutes, not relieved by nitrates.
What are atypical MI symptoms?
More common in elderly, women, and diabetics:
Epigastric pain, dyspnoea, dizziness, or syncope.
What are signs of cardiogenic shock in MI?
Hypotension, cold clammy skin, confusion, reduced urine output.
What are the ECG findings in STEMI?
ST-segment elevation in affected leads.
Reciprocal ST depression in opposite leads.
Q waves appear later, indicating full-thickness infarction.
What are the ECG findings in NSTEMI?
ST depression or T wave inversion, no ST elevation.
What is the role of troponin in MI diagnosis?
Troponin I/T → Highly specific for myocardial damage, rises 3-6 hours after MI, peaks at 24 hours, remains elevated for 7-10 days.
What imaging tests are used for MI diagnosis?
Coronary angiography → Identifies the blocked artery.
Echocardiography → Assesses wall motion abnormalities.
What are the immediate treatments for STEMI?
“MONA-B” approach:
Morphine → Pain relief.
Oxygen → If hypoxic.
Nitrates → Vasodilation.
Aspirin + P2Y12 inhibitor (e.g., clopidogrel) → Prevent clot progression.
Beta-blockers → Reduce heart rate and oxygen demand.
What are the main revascularization strategies for MI?
Primary Percutaneous Coronary Intervention (PCI) → Preferred for STEMI, restores blood flow via stenting.
Thrombolysis (fibrinolytic therapy) → Used if PCI is unavailable within 2 hours.
Coronary Artery Bypass Grafting (CABG) → For multi-vessel disease.
What medications improve long-term survival post-MI?
Dual antiplatelet therapy (Aspirin + P2Y12 inhibitor).
Beta-blockers → Reduce mortality.
ACE inhibitors/ARBs → Prevent heart failure and remodeling.
Statins → Reduce cholesterol, stabilize plaques
