Acute Coronary Syndromes

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ACS Unveiled - Rogue Clots & Risks

⭐ Unstable angina, NSTEMI, and STEMI represent a spectrum of acute myocardial ischemia, primarily due to atherothrombosis.

  • Pathophysiology: Atherosclerotic plaque rupture/erosion → thrombus formation → ↓ coronary blood flow.

    • Key event: Platelet activation & aggregation, coagulation cascade. Atherosclerosis progression to blood clot formation
  • Spectrum of ACS - Key Differences:

    FeatureUnstable Angina (UA)NSTEMISTEMI
    ECGST↓/T inv (transient) / NormalST↓/T inv (persistent) / NormalST↑ (persistent)
    Cardiac BiomarkersNormal↑ Troponins↑ Troponins
    Coronary OcclusionPartial/TransientPartial (non-occlusive thrombus)Complete (occlusive thrombus)

ACS Detectives - ECGs, Enzymes, Scores

  • ECG (obtain within 10 mins):
    • STEMI: ST-Elevation ≥1mm in ≥2 contiguous leads (V2-V3: ≥2mm M, ≥1.5mm F); new LBBB.
    • NSTEMI/UA: ST-Depression ≥0.5mm; T-wave inversion ≥1mm; dynamic changes. ACS Pathophysiology and ECG Findings
  • Cardiac Enzymes (Biomarkers):
    • Troponin (cTnI/T): Preferred. Rise 2-4h, peak 12-24h, lasts 7-14d.
    • CK-MB: Rise 4-6h, peak 12-24h, normal 48-72h. Useful for re-infarction.
  • Risk Scores:
    • TIMI (UA/NSTEMI): 7-point score (Age, Markers, ECG, Risk factors, Ischemia, CAD, Aspirin). 📌 Mnemonic: AMERICA.
    • GRACE: Predicts in-hospital & 6-month mortality; more complex, more accurate.

⭐ High-sensitivity cardiac troponins are the preferred biomarkers for diagnosing myocardial injury in ACS due to their high sensitivity and specificity.

ACS Battle Plan - Timely Interventions

  • All ACS - Initial Rx:

    • Oxygen (if SpO2 <90%).
    • Aspirin (300-325mg chewed).
    • Nitroglycerin (SL, if SBP >90mmHg, no RV infarct/PDE5i).
    • Morphine (if pain persists).
    • P2Y12 inhibitor (e.g., Clopidogrel 300-600mg or Ticagrelor 180mg loading dose).
    • Anticoagulant (e.g., LMWH/UFH).
    • High-dose Statin (e.g., Atorvastatin 80mg).
    • Beta-blocker (oral, within 24h, if no contraindications).
  • STEMI: Reperfusion Therapy

    • Goal: Rapid restoration of coronary flow.
  • NSTEMI/UA: Risk Stratification & Strategy
    • Risk scores: TIMI, GRACE.
    • 📌 DAPT: Aspirin + P2Y12 inhibitor (Clopidogrel/Ticagrelor/Prasugrel).

STEMI Reperfusion Strategies: PCI vs Fibrinolysis

⭐ Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor is a cornerstone of ACS management for at least 12 months post-event unless contraindicated.

ACS Aftercare - Healing & Shielding

  • Post-MI Complications:

    ComplicationTimingKey Features
    Arrhythmias (VF/VT)<48 hrsCommon early death
    Papillary Muscle Rupture2-7 daysSevere MR, new murmur
    VSD3-5 daysHarsh pansystolic murmur
    Free Wall Rupture3-7 daysTamponade, PEA
    LV AneurysmWks-MosPersistent ST↑, HF
    Dressler's SyndromeWks-MosPericarditis, fever
    Mural ThrombusDays-WksEmbolic risk
  • Secondary Prevention (Lifelong): 📌 ABCDE

    • Aspirin (75-100mg) + P2Y12-I (Ticagrelor 90mg BD $\ge$12mo).
    • Beta-blocker.
    • Cholesterol: Statins (LDL-C <55 mg/dL). Quit Smoking.
    • Diet, DM control (HbA1c <7%).
    • E ACEi/ARB (LVEF $\le \text{40%}$/HTN/DM/CKD). Exercise.

⭐ Dressler's syndrome (post-MI pericarditis) typically occurs weeks to months after MI and responds to NSAIDs or corticosteroids.

High‑Yield Points - ⚡ Biggest Takeaways

  • STEMI demands immediate reperfusion: PCI <90 min or fibrinolysis <30 min if PCI delayed >120 min.
  • NSTE-ACS (NSTEMI/UA) requires risk stratification (TIMI/GRACE scores) and dual antiplatelet therapy (DAPT).
  • ECG is crucial: ST elevation (STEMI), ST depression/T-wave inversion (NSTE-ACS).
  • Cardiac troponins differentiate Myocardial Infarction (MI) (↑) from Unstable Angina (UA) (normal).
  • Aspirin plus a P2Y12 inhibitor (e.g., ticagrelor, prasugrel) are core antiplatelets.
  • Beta-blockers, statins, and ACE inhibitors/ARBs are vital for long-term management.
  • Initial approach includes MONA (Morphine, Oxygen if SpO2 <90%, Nitrates, Aspirin).

Practice Questions: Acute Coronary Syndromes

Test your understanding with these related questions

A 40-year-old male patient presents to the Emergency department with central chest pain for 2 hours. The ECG shows ST segment depression and cardiac troponins are elevated. The patient has a positive history of previous PCI 3 months back. He is administered Aspirin, Clopidogrel, Nitrates, and LMWH in the Emergency Department and shifted to the coronary care unit. What is the best recommended course of further action?

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Flashcards: Acute Coronary Syndromes

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In Inferior wall MI with hypotension, brisk administration of _____ is recommended to prevent cardiogenic shock

TAP TO REVEAL ANSWER

In Inferior wall MI with hypotension, brisk administration of _____ is recommended to prevent cardiogenic shock

IV fluids

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