The use of the iHealth HS5 scale, like any other device that makes a weak electrical signal pass through the body, is not recommended for persons with a pacemaker or any other electronic medical implant.
Persons with non-electronic medical implants can use the iHealth HS5 scale without risk.
Metal implants can affect the accuracy of the body fat measurement, giving slightly underestimated results. However, if these implants are present in your body at each measurement you can just as effectively track the changes in your body fat over time.
*credit to Sylvain of iHealth Labs EU
https://helpcenter.ihealthlabs.eu/hc/en-gb/articles/115005876365-iHealth-HS5-I-have-a-pacemaker-can-I-use-the-scale-