Dysfunction of implantable defibrillators caused by slot machines.

The electrogram storage is a feature offered by the last generation of defibrillators, which enables the physician to establish whether the sensed episode and the electrical therapy delivered by the device was appropriate. The incidence of electromagnetic interferences may be higher than initially suspected with the latest generation of defibrillators. Such interference was documented in 4 out of 100 patients over a 24-month period. The electrical interference occurred in all four of them, while they were playing with slot machines. In the RR interval history, irregular QRS sensing of variable frequency was documented in some episodes. The intervals were irregular and nonphysiological satisfying the rate cut-off criteria in an intermittent and nonsustained way. There may be high risk of electromagnetic interference between slot machines and defibrillators. Our experience calls for a warning to all defibrillator patients and, perhaps some regulatory intervention.