Key Concepts
Overview
Myocardial infarction (MI) occurs when prolonged ischemia causes irreversible myocardial cell death. MI is classified by ECG pattern and biomarker elevation: - STEMI (ST-elevation MI): complete occlusion of a coronary artery; ST elevation in ≥ 2 contiguous leads. Requires emergent reperfusion within 90 minutes (door-to-balloon time ≤ 90 min for primary PCI, or fibrinolytics within 30 minutes if PCI unavailable). - NSTEMI (non-ST-elevation MI): partial or temporary occlusion; elevated troponin without ST elevation. Managed with anticoagulation and early catheterization (within 24–72 hours). - Unstable angina: chest pain without troponin elevation — no myocardial necrosis but high risk of progression. For NCLEX-RN, recognize the classic presentation, understand the time-sensitive reperfusion window, and know the nursing priorities in the first hours. On the exam, writers often pair stable-sounding options with unstable data—notice the mismatch before you commit. If the stem names a license or role, reread that line; scope errors are classic trap answers even when the clinical topic is familiar. Run a 60-second scan: breathing work and oxygenation, perfusion and end organs, neuro baseline, likely infection sources, and devices that can...