Research has found that handheld electro-shockers commonly used for self-defense can potentially interact with cardiac implantable electronic devices (CIEDs) such as pacemakers, putting individuals at risk.

The study in Heart Rhythm shows that the individual interactive risk is primarily based on the applied voltage, but also on the manufacturer and type of implanted CIED.

The use of TASER pistols by security forces has been controversial because of the associated health risks for subjects receiving a TASER shock. In contrast to TASER pistols, which shoot electrical darts over a distance of up to 10 meters and transmit electrical currents through large parts of a person's body, a handheld electro-shocker delivers energy superficially by directly applying the device to a target.

The handheld electro-shockers tested in this study are legal to own and carry in most countries, and therefore, patients with CIEDs might have an increased risk of coming into contact with these devices. This is the first time a study has evaluated the effects of these electro-shockers on CIEDs.

Lead investigator Felix K. Wegner, MD, Department of Cardiology II—Electrophysiology, University Hospital Muenster, Germany, says, "Current literature and manufacturer guidelines don't fully address patients' concerns about living with a CIED.

"To investigate the interaction between electro-shockers and cardiac devices, we devised an experimental model in which six pacemakers and ten implantable cardioverter-defibrillators from different manufacturers were implanted in a subcutaneous and submuscular location in an isolated section of a porcine chest and connected to an interactive heart simulator.

"Subsequently, three types of electro-shockers were applied to the chest."

Data analysis showed that the electro-shocker with the highest applied voltage ("PowerMax," 500,000 volts) had a high potential of interaction with all tested CIEDs.

Depending on the CIED manufacturer, there was a relevant risk of inadequate shock delivery by implantable cardioverter-defibrillators. Conversely, smaller handheld electro-shockers with lower applied voltages ("Electric Guard," 250,000 volts, and "Bikenda," <50,000 volts) had a significantly reduced risk of interaction.

Dr. Wegner notes, "We were surprised to find that submuscular CIED implantation did not significantly reduce the risk of interaction when compared to subcutaneous CIED implantation. Additionally, we expected the distance between the electro-shocker application and the CIED implantation site to have a greater impact on the risk of interaction than it did in the present study.

"These unexpected findings indicate that electro-shocker applications to a large part of a patient with a CIED's body may pose a relevant risk of interaction with the respective CIED."

Senior author Lars Eckardt, Department of Cardiology II—Electrophysiology, University Hospital Muenster, Germany, concludes, "Commercially available handheld electro-shockers pose a relevant risk of interaction when applied in proximity to CIEDs.

"The risk of interaction is primarily dependent on applied voltage, but resulting changes in cardiac device behavior differ according to the respective manufacturer.

"In this experimental study, which is the result of an excellent and fruitful cooperation with our local traumatologists, no signs of cardiac device damage were noted due to handheld electro-shocker application. Further research is warranted to evaluate whether our findings are transferable to all current and legacy CIED systems."