Back in January 2021 we cautioned patients with pacemakers and ICDs about the risk posed to them from smartphones, particularly if stored in a pocket over the cardiac device site (see here). Now it’s time to turn the spotlight on smart watches.
Smart watches and some either types of wearable technology such as fitness trackers send a small electrical current, imperceptible to the wearer, into the body and read the signals that come back to generate information such as heart rate and oxygen saturation. This is known as bioimpedance and is completely harmless in most people. However, this electrical current may cause a pacemaker to behave as though the heart is beating normally when actually it isn’t, and could trigger delivery of an unnecessary shock to a patient with an ICD.
Patients with pacemakers and ICDs are generally advised to keep devices such as smartphones and tablets at least 6 inches away from their pacing site to avoid interference. With smart watches and other wearable technologies which use bioimpedance to gather data, the advice is much stricter and patients with pacemakers and ICDs should avoid these devices completely.