Cardiovascular Emergencies
Core concepts
Acute coronary syndrome anchors this domain. Know the STEMI thresholds (≥1 mm in two contiguous limb leads; ≥2 mm in V2–V3 for men ≥40, ≥2.5 mm for men <40, ≥1.5 mm for women) and the equivalents: posterior MI (ST depression V1–V3 with upright T waves), left main or severe multivessel disease (aVR elevation with diffuse depression), de Winter and Wellens patterns, and the Sgarbossa criteria for LBBB. Aortic dissection causes abrupt tearing pain, pulse or blood pressure differential, or new aortic regurgitation; the chest radiograph is insensitive, so CT angiography is the test. Acute decompensated heart failure is managed by profiling (wet/dry, warm/cold): nitrates plus noninvasive ventilation for hypertensive pulmonary edema, diuretics for congestion, inotropes or pressors for cardiogenic shock. Unstable tachyarrhythmias get synchronized cardioversion. Stable regular narrow-complex SVT gets adenosine; stable wide-complex tachycardia is treated as VT with amiodarone or procainamide. In pre-excited atrial fibrillation (WPW), AV nodal blockers can accelerate conduction into ventricular fibrillation - use procainamide or electricity instead. Bradycardia: atropine boluses, then transcutaneous pacing or epinephrine/dopamine. Tamponade shows Beck triad, pulsus paradoxus, and electrical alternans; treat with volume and pericardiocentesis.
Traps
A single early troponin does not exclude MI; repeat testing and ECGs matter. Labeling chest pain as GERD or anxiety is the classic miss. Nitroglycerin in an inferior MI with right ventricular involvement can cause profound hypotension. Giving thrombolytics to a dissection is catastrophic. Treating rate-related demand ischemia as plaque rupture (or vice versa) sends the patient down the wrong pathway.
Rule of thumb
Hypotension plus tachycardia is shock until proven otherwise; obtain an ECG within 10 minutes of arrival and repeat it whenever the story changes.