Human Electrical Muscular Incapacitation and Effects on QTc Interval

Human Electrical Muscular Incapacitation ( HEMI ) is used to subdue combative individuals. Changes in cardiac electrical activity have been proposed as the cause of death in a small fraction of these individuals. The current study sought to determine whether changes in QT c interval occur after HEMI exposure. Twenty‐four participants had EKG readings before a 5‐second HEMI exposure and within 30 min after exposure. All subject EKG s were read by a data‐blinded cardiac electrophysiologist who calculated a QT corrected ( QT c) interval. QT c interval was calculated using Bazett method. QT c prolongation was defined as >430 ms and a threshold of 30 ms for identifying QT c lengthening. Five participants experienced QT c prolongation and six had QT c lengthening. One participant developed QT c prolongation exceeding 500 ms, which carries a risk of developing multifocal ventricular tachycardia. These results suggest that HEMI exposure may cause EKG changes with a risk of ventricular tachycardia.