Possible Influences of Spark Discharges on Cardiac Pacemakers

Abstract

Exposure to spark discharges may occur beneath high voltage transmission lines when contact is initiated with a conductive object (such as a motor vehicle) with the spark discharge mediated by the ambient electric field from the line. The objective of this study was to assess whether such exposures could interfere with the normal functioning of implanted cardiac pacemakers (PMs). The experiment consisted of PMs implanted in a human-sized phantom and then exposed to spark discharge through an upper extremity. A circuit was designed that produced spark discharges between two spherical electrodes fed to the phantom's left hand. The circuit was set to deliver a single discharge per half cycle (every 10 ms) about 10 μs in duration with a peak current of 1.2-1.3 A, thus simulating conditions under a 400-kV power line operating at 50 Hz. Of 29 PMs acquired, all were tested in unipolar configuration and 20 in bipolar configuration with exposure consisting of 2 min of continuous exposure (one unit was exposed for 1 min). No interference was observed in bipolar configuration. One unit in unipolar configuration incorrectly identified ventricular extra systoles (more than 400 beats min(-1)) for 2 s. The use of unipolar configuration in new implants is extremely rare, thus further minimizing the risk of interference with the passage of time. Replication of this study and, if safety for human subjects can be assured, future testing of human subjects is also advisable.

Occupational Exposure to Electromagnetic Fields and Health Surveillance according to the European Directive 2013/35/EU

“…Workers with active implanted medical devices (AIMD) may be at an increased risk of interference of EMF with the devices; among the main examples of these devices are cardiac pacemakers, cardiac defibrillators, cochlear implants, brainstem implants, inner ear prostheses, neurostimulators, retinal encoders, implanted drug infusion pumps, and others [7,21]. EMF interference with AIMDs can be possible also in the case of relatively low EMF exposure, possibly below the 2013/35/EU directive ELVs, causing temporary disturbances of the sensing and/or stimulating functions of the devices, or, in the worst cases, determining permanent malfunctions, deactivations needing resets of the implants, and even inappropriate or unneeded stimulations [22][23][24][25][26]. Of course, interference problems can be possible also in case of body-worn medical devices, such as external hormone infusion pumps, hearing aids, continuous glucose monitoring systems, and metalized drug-delivery patches [7,21].…”

The Possibility of Decreasing 50-Hz Electric Field Exposure near 400-kV Power Lines with Arc Flash Personal Protective Equipment

“…Typically, the workers are not grounded with a conductor and do not wear equipment that would specifically protect them from exposure to the electric field. Occupational and public electric field exposures have been studied earlier in Finland [1,2,3,4,5,6,7,8]. For example, cardiac pacemakers and implantable cardioverter defibrillators in the electric fields of 400-kV power lines have been tested [1,2].…”

“…Threshold values for these effects are lowest at frequencies between 10 and 100 Hz. Spark discharges can occur when an individual comes into very close proximity with an object of a different electric potential without actually touching it [3,10]. Indirect effects for the threshold current (mA) at a 50-Hz frequency are touch perception (0.2–0.4 mA), pain on finger contact (0.9–1.8 mA), painful shock (8–16 mA), and severe shock (12–23 mA) [11].…”