A 38-year-old woman presents with atypical-sounding low-risk chest pain. Describe and interpret her initial 12-lead electrocardiogram:
INTERPRETATION:
- 84 bpm
- Sinus rhythm
- PR interval 150 ms
- Normal QRS axis (-7°)
- QRS duration 82 ms
- QTc 441 ms
- Early repolarisation phenomenon:
- Widespread concave ST elevation, most prominent in the precordial leads (V2-5)
- Notching/slurring at the J-point
- Prominent, slightly asymmetrical T-waves that are concordant with the QRS complexes
- No reciprocal ST elevation to suggest a STEMI
- Global negativity in lead III
- Greater P-wave amplitude in lead I compared with lead II (usually the other way round)
DIAGNOSIS:
Left upper and lower limb electrode reversal.
This has the following effects on the ECG:
- Lead III becomes inverted
- Leads I and II switch places
- Leads aVL and aVF switch places
- Lead aVR remains unchanged
