Experimental studies have reported that strong electric and magnetic fields have the potential to affect the function of a pacemaker if these fields exceed a pacemaker’s immunity level. Pacemakers are designed to minimize the effect of interference whatever the source and so even though a change in function may be noted, it does not mean that a patient is at risk. Magnetic field levels directly under a transmission line are but a fraction of a pacemaker’s immunity level to magnetic fields. Electric field levels under some transmission lines may be comparable to the pacemaker’s electric field immunity level. While electric fields may affect some models of pacemakers, this would be most likely directly under higher voltage AC transmission lines operating at 500 kV since electric field levels drop rapidly with distance and are shielded by many materials. AltaLink is not aware of any cases of confirmed interference to pacemakers by transmission lines.
In addition, most modern pacemakers are designed to filter out electrical interference or revert to a safe mode of steady pacing (called asynchronous pacing) if interference becomes too great. Your doctor will be able to identify if interference has occurred by reviewing the telemetry data on your next visit. If you have a concern about potential interference from exposure to an electric field, contact your doctor. AltaLink will work together with your doctor to help you determine if your device is immune to electrical fields from a transmission line.