Key Points:
- The Must-Know DDx hub is your rapid reference for ECG-centered differential diagnosis in acute care.
- Use it when you recognize an ECG abnormality but need a focused list of the most important possible causes before anchoring too early.
- In acute care, rule out killers first. Start with life-threatening causes, then work toward less urgent and benign explanations.
- Think in terms of the ECG finding, not just the presumed diagnosis: wide regular tachycardia, diffuse ST elevation, prolonged QT, no clear P waves.
- Your differential should evolve with the clinical story, serial ECGs, labs, imaging, and bedside echo.
How to Use This Hub:
1. Name the ECG abnormality (not the diagnosis): describe what you actually see: wide regular tachycardia, diffuse ST elevation, prolonged QTc, no clear P waves, etc.
2. Open the relevant DDx post: use the buttons below to jump directly to the focused differential for that specific ECG abnormality.
3. Rule out killers first: once you have the differential in front of you, use the clinical story, vitals, serial ECGs, labs, and bedside data to prioritize the most dangerous causes first.
Search above or browse the Must-Know DDx collection here:
Key Clinical Pearls:
- Always consider the worst-case diagnosis first. For any abnormal ECG, explicitly consider acute coronary occlusion, malignant arrhythmia, hyperkalemia or toxicity, high-risk PE, tamponade, and aortic catastrophe when clinically plausible.
- Do not anchor on the first explanation. A familiar pattern can still represent a dangerous mimic.
- Serial ECGs are a diagnostic tool. Dynamic change may expose evolving ischemia, reperfusion, worsening toxicity, or conduction deterioration.
- Avoid single-lead thinking. Territorial patterns, reciprocal change, QRS morphology, and comparison to prior ECGs are often more useful than any isolated finding.
- If the ECG is unexplained in a sick patient, treat it as high risk until proven otherwise.
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