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- 60 bpm
- Atrial activity present but inverted P wave leads V2 & V5
- PR - Normal
- QRS - Normal
- T wave inversion leads II, III, aVF, V1-2, V5
- Abnormal R wave transition in precordial leads
- Negative QRS leads V1-2
- Positive QRS leads V3-4
- Negative QRS leads V5-6
- Complete lead inversion V2 & V5 (Negative P, negative QRS, negative T)
The combination of abnormal R wave transition, complete lead inversion leads V2 & V5 plus extreme axis should always alert us to the possibility of lead reversal.
This is clearly not a 'simple' reversal i.e. only 2 leads misplaced but far more complex. The odds of every lead being attached to a patient incorrectly is very small but the connection between the leads and the machine is much easier to misconnect especially when old and worn. This what happened in this case with the connecting terminal for all the leads was placed upside down into the ECG machine with resultant lead swaps as below.
Expected lead Actual lead
References / Further Reading
Life in the Fast Lane
- Lead reversal
- Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.