Pulsewatch: A Smartwatch System Designed with Stroke Survivors for Continuous Monitoring of Atrial Fibrillation in Older Adults after Stroke or Transient Ischemic Attack (Preprint)

BACKGROUND Atrial fibrillation (AF) prevalence increases with age and may lead to stroke. Therefore, older adults are a group that may benefit most from AF screening. Yet older adult populations tend to lag younger groups in terms of adoption of, and comfort with, the use of mobile health applications. Furthermore, although mobile apps that can detect AF are available to the public, most of them are designed for intermittent AF detection and for younger users. No app designed for long-term AF monitoring has released detailed system design specifications that can handle especially large data collection, especially in this age group. OBJECTIVE In collaboration with AF patients and their medical providers, this study aimed to design an innovative smartwatch-based AF monitoring mHealth solution for the older adult population. METHODS Based on functionality that patients and caregivers suggested, we designed the Pulsewatch system. The resulting system consisted of linked smartwatch and smartphone applications, a website for data verification, and user data organization on a cloud server. The smartwatch in the Pulsewatch system continuously monitored the pulse rate with embedded AF detection algorithms, and the smartphone in the Pulsewatch system serves as the data transferring hub to our cloud storage server. The user interface of the smartwatch and smartphone apps were specifically designed for older adults at risk for AF. We improved our Pulsewatch system based on the feedback from focus groups consisting of stroke patients and healthcare providers. The Pulsewatch system was used by the intervention group for up to 6 weeks in the two Phases of our randomized clinical trial (NCT03761394). RESULTS At the conclusion of Phase 1, 90 trial participants who had used Pulsewatch app and smartwatch for 14 days completed a System Usability Scale (SUS) to assess the usability of the Pulsewatch system; 64% of participants endorsed that the smartwatch app is “easy to use.” For Phases 1 and 2 of the study, we collected 9224.4 hours of watch recordings from participants. The longest recording streak in Phase 2 was 21 days of consecutive recording out of the 30 days of data collection. CONCLUSIONS This is one of the first studies to provide a detailed design for a smartphone-smartwatch dyad for ambulatory AF monitoring. In it, we report on the system’s usability and opportunities to increase the acceptability of mHealth solutions among older patients with cognitive impairment. CLINICALTRIAL ClinicalTrials.gov NCT03761394 INTERNATIONAL REGISTERED REPORT RR2-10.1016/j.cvdhj.2021.07.002