Abstract
The rare dermatological condition X-linked ichthyosis (XLI) is associated with a substantially-increased risk of cardiac arrhythmias. Arrhythmias predispose to multiple serious health conditions, and there is a need to identify them at an early stage, ideally using non-invasive, convenient, cost-effective, and reliable wearable technology methods. We tested the feasibility of monitoring heart rhythms using an Apple Watch in five adult males from the United Kingdom diagnosed with XLI. Participants returned routine electrocardiogram (ECG) traces from the watch three times per week for eight weeks (plus any traces associated with 'watch alerts' indicating arrhythmic episodes) for cardiologist review. Participant feedback was also obtained on the perceived usability/wearability of the watch/app, and on the study requirements. Participants were generally happy with the study conduct, found the watch/app straightforward to use, and there was a > 95% data return rate. Minor protocol improvements were suggested. There were few issues reported with wearability of the watch. Three participants exhibited no ECG abnormalities, but two presented with ventricular ectopic beats (VEs). Only one watch 'alert' ECG was returned, and this was considered normal sinus rhythm, suggesting the possibility of 'false positive' calls. Based on our small sample, smartwatch-based screening for cardiac rhythm abnormalities in the high-risk male XLI population appears useful, feasible, and acceptable to patients and a larger-scale clinical trial is warranted. Potentially, such devices may be more suited to detecting persistent abnormalities rather than unpredictable, acute, arrhythmic episodes. The high VE burden in some participants with XLI is consistent with septal defects underlying arrhythmia risk.