Recognizing and Confirming MI
Classic MI presents with substernal chest pain radiating to the jaw or left arm, diaphoresis, and nausea unrelieved by rest or nitroglycerin. Atypical presentations, especially in women and diabetics with neuropathy, include fatigue, indigestion, or back pain, and the NCLEX tests whether you'll dismiss these as non-cardiac. Troponin I and T are the most specific cardiac biomarkers, rising within 3-4 hours and remaining elevated for days, while CK-MB rises and falls faster and is used to detect reinfarction. A 12-lead ECG showing ST-elevation indicates STEMI requiring emergent reperfusion, while ST-depression suggests NSTEMI or ischemia.
MONA and Time-Critical Reperfusion
MONA is a memory aid, not a strict order: morphine for pain unrelieved by nitrates, oxygen if saturation is low, nitroglycerin for vasodilation (hold if systolic BP under 90 or recent PDE5 inhibitor use), and aspirin to inhibit platelet aggregation, chewed for faster absorption. For STEMI, door-to-balloon time for PCI should be under 90 minutes, and door-to-needle time for fibrinolytics should be under 30 minutes. Absolute contraindications to thrombolytics include active internal bleeding, recent hemorrhagic stroke, and suspected aortic dissection. NCLEX questions often test whether you recognize a contraindication before the drug is given.
Post-MI Complications and Monitoring
Dysrhythmias, especially ventricular fibrillation, are the leading cause of death in the first hour after MI, so continuous cardiac monitoring is essential. Cardiogenic shock develops when a large portion of myocardium is damaged, presenting with hypotension, tachycardia, and cool clammy skin. Papillary muscle rupture causes a new holosystolic murmur and acute mitral regurgitation, usually 2-7 days post-MI. Cardiac rehabilitation teaching includes gradual activity progression, avoiding Valsalva maneuver, and recognizing recurrent angina symptoms. Discharge teaching must cover risk factor modification, medication adherence including antiplatelets and statins, and when to call emergency services versus a provider.