Background: Commercially available wearable devices, capable of measuring cardiac rhythm, are gaining popularity for convenient heart health monitoring. Accurate measurement of key intervals, specifically RR intervals for rhythm and QT and corrected QT (QTc) intervals for arrhythmia risk, is crucial for assessing potential cardiac morbidity. Objective: This study aimed to evaluate the agreement of RR, QT, and QTc intervals measured by a consumer wearable device (Withings ScanWatch series 1) with those measured using a research-grade 3-lead electrocardiogram (ECG; Biopac) and a clinically approved single-lead patch (Cardea SOLO). Methods: This was a cross-sectional study of 28 healthy adults aged 21 to 65 years, with a mean age of 39.4 (SD 13.0) years. Participants underwent 4 concurrent ECG measurements per device: twice seated at rest, once supine, and once after exercise. All RR and QT intervals were manually measured using standardized caliper software (EP calipers) by trained reviewers, and QTc was calculated using the Bazett formula. Agreement was assessed via repeated-measures correlation () and linear mixed-effects models (LMMs) for repeated-measures Bland-Altman analysis. Results: Strong agreement was observed for RR intervals when comparing the Withings ScanWatch with both the Biopac (=0.84; .001) and the SOLO (=0.80;

How the Apple Watch improves my life: fitness, heart-monitoring, unobtrusive reminders, timers, alarms, sleeping, and meditation

How the Apple Watch improves my life: fitness, heart-monitoring, unobtrusive reminders, timers, alarms, sleeping, and meditation

How the Apple Watch improves my life: fitness, heart-monitoring, unobtrusive reminders, timers, alarms, sleeping, and meditation