Wearable Devices for Patient Monitoring in Long QT Syndrome

• Wearable device (Device): This is an observational study that does not impact routine clinical care for participants

Primary outcomes

• 1. Determine the accuracy of repeated QT interval measurements using Fitbit-derived ECGs in patients with Long QT syndrome compared with the current standard (12-lead ECG and ambulatory monitors) [From enrollment to 3 months]
• 2. Establish intra-patient QT variability from weekly Fitbit-ECGs and frequency of measurements over 500ms. [From enrollment to 3 months]

Secondary outcomes

• 1. Establish the utility of wearable devices for determining symptom aetiology in LQTS. [From enrollment to 3 months]
• 2. Develop pipelines for the analysis of ECG data collected remotely including use of in-house QT automated algorithms for future machine learning applications. [From enrollment to 3 months]

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Clinical diagnosis of Long QT Syndrome
* Aged 18 years or over
* Phone with iOS version 15 or Android OS 9.0 or higher
* Able and willing to provide informed consent

Exclusion Criteria:

* Unwilling or unable to give consent
* Ventricular pacing at recruitment
* Bundle branch block or pre-excitation at baseline

• William J Young, MBBS, PhD, Principal investigator, Queen Mary University of London and St Bartholomew's Hospital