Pathological ECG that seemed normal following electrode misplacement.

We report the case of a 57-year-old woman found at home who received an ECG after having recovered from a seizure, without any clinical cardiac anomaly. The ECG revealed an elevation of the ST segment from the V1 to V5 leads and negative T waves from V1 to V5 leads. At her hospital admission, the emergency care unit (ECU) nurse performed another ECG. It no longer showed any repolarisation anomaly. However, the ECU nurse had put the precordial electrodes 3 cm too low, probably due to the patient's voluminous breasts. In the end, the pathological trace reappeared after we returned the electrodes to their initial positions. Malpositioning of the electrodes caused a seemingly normal ECG result with life-threatening consequences.