ECG library
Long QT
coreA 44-year-old on methadone, ondansetron, and now ciprofloxacin. Routine ECG before discharge.
25 mm/s · 10 mm/mV · synthetic tracing
100%
Calipers:2000 ms50.0 small boxes30 bpm if R-RDrag the orange markers. One small box = 40 ms.
Key findings
- QTc above 500 ms
- An additive medication list
- Check potassium and magnesium
Learning points
- Eyeball rule: a QT beyond half the RR interval deserves a formal measurement.
- The fix is subtraction: stop the QT-prolonging drugs, replace K and Mg, and repeat the tracing.
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