Transient hyperkalemia-induced T-wave oversensing as a cause of inappropriate ICD discharges.

The present case describes a patient with an implantable cardioverter-defibrillator (ICD) who reported several ICD inappropriate discharges due to transient T-wave oversensing in the setting of acute hyperkalemia. T-wave oversensing was detected only at telemetry interrogation while T-wave amplitude at surface 12-lead electrocardiogram was normal. Oversensing was abolished by reducing potassium levels and by device reprogramming. This case report underscores the importance of identifying a potentially reversible cause of ICD inappropriate discharges and the utility of careful review of stored electrograms. <Learning objective: This case report underscores the importance of understanding the diversity of causes of implantable cardioverter-defibrillator malfunctioning and the utility of careful review of stored electrograms.>.