Acute Coronary Syndrome Lecture Notes
Introduction
- Topics Covered: Acute coronary syndrome, unstable angina, STEMI, NSTEMI, Dressler syndrome, cocaine-induced MI.
- Purpose: Key points for PANCE exam preparation.
Acute Coronary Syndrome (ACS)
- ACS refers to suspicion or confirmed acute myocardial ischemia or infarction.
- Often due to plaque rupture leading to secondary artery thrombosis.
Types of ACS
- Unstable Angina: Partial occlusion of coronary arteries.
- NSTEMI (Non-ST Elevation Myocardial Infarction): Positive cardiac enzymes without ST elevation.
- STEMI (ST Elevation Myocardial Infarction): Complete 100% occlusion and ST elevation on EKG.
Clinical Manifestations of ACS
- Pain Characteristics:
- Not relieved with rest or nitroglycerin.
- Lasts over 30 minutes.
- Can radiate to the left arm, jaw, back.
- Non-positional, non-pluritic, and non-reproducible.
- Sympathetic Activation: Tachycardia, diaphoresis, nausea, vomiting.
- Atypical Presentations: Syncopal episodes, weakness, palpitations, dyspnea, or epigastric pain especially in women, elderly, and diabetics.
Diagnosing ACS
- EKG:
- Unstable Angina: No ST elevation, possible T-wave inversion, or ST depression.
- NSTEMI: Similar EKG to unstable angina but with positive cardiac enzymes.
- STEMI: ST elevation in two or more contiguous leads.
- Cardiac Biomarkers:
- Troponin: Most sensitive and specific, rises 4 hours post-MI, stays elevated up to 10 days.
- CK-MB: Used if troponin is unavailable or in cases of reinfarction.
- Myoglobin: Peaks quickly (2 hours), not commonly used.
Treatment of ACS
- Initial Treatment (MOAN):
- Morphine: Only if pain is unmanageable.
- Oxygen: If SpO2 <90%.
- Aspirin: 325 mg chew and swallow upon arrival.
- Nitrates: Avoid if patient is hypotensive, has right ventricular MI, or has taken PDE5 inhibitors.
- Long-term Management (BASH):
- Beta blockers: unless contraindicated.
- ACE inhibitors: Improves mortality, started within 24-48 hours.
- Statins: High intensity for patients with CAD.
- Heparin or other antithrombotics.
Reperfusion Therapy
- Percutaneous Coronary Intervention (PCI): Preferred, done within 90 minutes.
- Thrombolytics (e.g., TPA): Used if PCI is not available within 90 minutes.
Miscellaneous Topics
- Cocaine-Induced MI:
- Presentation similar to MI due to coronary artery vasospasm.
- Treatment: Calcium channel blockers, avoid non-selective beta blockers.
- Dressler Syndrome (Post-MI Pericarditis):
- Treatment with aspirin or colchicine.
- Right Ventricular Infarction:
- Clinical triad: Increased JVP, clear lungs, Kussmaul sign.
- Avoid nitrates and morphine.
Important EKG Leads for MI
- Inferior Wall MI: Leads II, III, aVF.
- Anterior Wall MI: Leads V2-V5.
- Septal Wall MI: Leads V1-V2.
- Lateral Wall MI: Leads I, aVL, V5-V6.
- Posterior Wall MI: ST depression in V1-V2, confirmed with posterior leads V7-V9.
Review Questions
- Atypical ACS Presentation Populations: Women, elderly, diabetics.
- Cocaine-Induced MI Treatment: Calcium channel blockers.
- Inferior Wall MI EKG Leads: II, III, aVF.
- Fastest Peaking Cardiac Biomarker: Myoglobin.
- Post-MI Pericarditis: Dressler syndrome.
This lecture provides a comprehensive overview of acute coronary syndrome, its types, clinical manifestations, diagnosis, and treatment. Remember, EKG and troponins are key for diagnosis. Treatment involves a systematic approach using MOAN and BASH mnemonics. Reperfusion therapy is critical for restoring blood flow in patients with acute MI.