A case of inappropriate implantable cardioverter defibrillator therapy induced by T‐wave oversensing due to hyperkalemia

Abstract

There have been reports of hyperkalemia-induced T-wave oversensing in patients with implantable cardioverter defibrillators (ICDs). However, a comparison of T-wave amplitudes and morphologies between the surface 12-lead electrocardiogram (ECG) and ICD electrogram has not been reported. We present the case of a 70-year-old man who received inappropriate ICD shocks due to hyperkalemia-induced T-wave oversensing. The T-wave amplitudes on both the ICD electrogram and 12-lead ECG corresponded and normalized after normalization of the potassium level.

Inappropriate subcutaneous implantable cardioverter-defibrillator shocks for bradycardia

“…Differences between the action potential characteristics of ventricular endocardial and epicardial tissues and predominant distribution of the I k1 in the endocardial tissue leads to a strong association of extracellular potassium concentration with the repolarization process. 3 In addition, the resting membrane potential becomes less negative with hyperkalemia thereby reducing the rate of rise of phase 0 which causes widening of the QRS complex. 4 As a result, patients with cardiac devices who develop hyperkalemia are vulnerable to T wave oversensing and QRS over-counting.…”