Acute Coronary Syndromes

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.

• Spectrum of ACS - Key Differences:

  Feature	Unstable Angina (UA)	NSTEMI	STEMI
  ECG	ST↓/T inv (transient) / Normal	ST↓/T inv (persistent) / Normal	ST↑ (persistent)
  Cardiac Biomarkers	Normal	↑ Troponins	↑ Troponins
  Coronary Occlusion	Partial/Transient	Partial (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.
• 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).

⭐ 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:

  Complication	Timing	Key Features
  Arrhythmias (VF/VT)	<48 hrs	Common early death
  Papillary Muscle Rupture	2-7 days	Severe MR, new murmur
  VSD	3-5 days	Harsh pansystolic murmur
  Free Wall Rupture	3-7 days	Tamponade, PEA
  LV Aneurysm	Wks-Mos	Persistent ST↑, HF
  Dressler's Syndrome	Wks-Mos	Pericarditis, fever
  Mural Thrombus	Days-Wks	Embolic 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).