Cardiovascular System
Core concepts
Organize cardiovascular questions into four buckets: ischemia, pump failure, rhythm, and vascular catastrophe.
Ischemia: troponin rises within hours and peaks near 24 hours, so a single early normal value never excludes myocardial infarction. STEMI shows ST elevation in contiguous leads with reciprocal depression; pericarditis shows diffuse ST elevation, PR depression, and pleuritic positional pain.
Pump failure: BNP supports but does not establish the diagnosis. HFrEF is a dilated ventricle with reduced ejection fraction; HFpEF is a stiff ventricle with preserved ejection fraction, typically in an older hypertensive patient.
Murmurs: aortic stenosis is a crescendo-decrescendo systolic murmur radiating to the carotids; mitral regurgitation radiates to the axilla; mitral stenosis gives an opening snap and diastolic rumble; hypertrophic cardiomyopathy softens with squatting and handgrip and intensifies with Valsalva and standing.
Rhythm: an unstable tachyarrhythmia means electricity, a stable one means drugs; atrial fibrillation needs rate control plus stroke-risk stratification.
Vascular: aortic dissection is tearing pain with a pulse or blood pressure differential, and thrombolytics are contraindicated.
Traps
- Dismissing atypical chest pain in a diabetic or older adult without an ECG.
- Excluding dissection because the chest radiograph was normal.
- Giving nitrates or aggressive beta blockade to a hypotensive patient with right ventricular infarction or acute decompensation.
- Treating every pericardial effusion with a needle.
Rule of thumb
ST elevation in II, III, and aVF with reciprocal change in I and aVL is an inferior STEMI; if that patient is hypotensive, suspect right ventricular involvement and give a fluid bolus rather than nitroglycerin.