| EKG Finding | Differentials |
|---|---|
| RAD (Right Axis Deviation) | Normal Variation: vertical heart with an axis of 90º Right Ventricular Hypertrophy (RVH) Right heart strain (e.g. PE) Left Posterior Fascicular Block Pre-excitation Syndrome (Wolff-Parkinson-White) Lateral Wall Myocardial Infarction |
| LAD (Left Axis Deviation) | Normal Variation Left ventricular hypertrophy Left bundle branch block Left anterior fascicular block Pre-excitation syndromes (Wolff-Parkinson-White) Inferior wall myocardial infarction |
| Early R-wave progression | Posterior MI RVH RBBB WPW |
| Poor R-wave progression | Anterior MI LVH RVH Cor-pulmonale |
| Important differentials for Q waves | MI LVH RVH Cor-pulmonale (Q waves in inferior and anterior leads) Cardiomyopathy |
| Important ST-T changes | Non-specific ST-T changes: < 1 mm ST elevation/ depression; flat T- waves or < 1 mm inversion of T- waves MI/ Angina Pericarditis Early repolarization Juvenile T waves LVH: ST depression and T- inversion, typically in I, aVL, V5, V6. Can be seen in other leads as well RVH: ST depression and T- inversion, typically in V1-3 Bundle Branch blocks Persistent ST- elevation (Usually present for over 3 weeks): Consider ventricular aneurysm |
| Peaked T-waves | Hyperkalemia MI Intracranial bleed LVH/ RVH LBBB |
| Deep T-waves | MI Intracranial bleed LVH/ RVH Takusubo cardiomyopathy Apical Hypertrophic cardiomyopathy Digoxin ST elevation in aVR with ST depression in multiple leads: suspect 3 vessel disease or left main disease |
| Short QTc | Hypercalcemia, Hyperkalemia, Congenital |
| Long QTc | Drugs Antiarrhythmics: IA, IC, III Antipsychotics, tricyclics Methadone Antibiotics: Floroquinolones, Macrolides Fluconazole Most antiemetics Hypocalcemia (T- waves usually normal) Hypomagnesemia Hypokalemia Congenital |
| Important differentials for U-waves | Hypokalemia Hypothermia Bradyarrhythmias Drugs (e.g., digoxin, class IA, and class III anti-arrhythmics) |
| Electrical alternans | Pericardial effusion Tachyarrhythmias Severe CHF/ CAD/ HTN |
| Inverted P-QRS-T in I and aVL and upright in aVR | Dextrocardia (shows reverse R wave progression) LA/RA lead reversal (Shows normal R- progression) |
| In WPW pattern, be cautious diagnosing the following on EKG | Ventricular hypertrophy MI and ischemia (since WPW can cause Q-waves and ST-T changes) Axis deviation Any other conduction abnormalities |
Smarter Medicine in a Snap
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