Safety and Utility of Smartphone‐Based Heart Monitors in Pediatric Patients With Cardiovascular Implantable Electronic Devices

BACKGROUND: Portable heart monitors enable on-demand electrocardiogram (ECG) recordings and enhance symptom-rhythm correlation. However, concerns have been raised regarding potential electromagnetic interference (EMI) from these monitors that may affect cardiovascular implantable electronic devices (CIEDs). The safety and clinical benefits of portable heart monitors in children and adolescents with implanted CIEDs remain to be established. OBJECTIVES: The primary objective was to determine whether KardiaMobile 6L and Apple Watch induce EMI, impacting the function of CIEDs in pediatric patients. Secondary aims included the assessment of the accuracy of heart rate measurement and their ability to detect non-capture events. METHODS: In this cross-sectional study, patients aged 5 years or older with implanted CIEDs were recruited from a tertiary pediatric cardiac center. Each subject had four 30 s ECGs acquired using KardiaMobile 6L and Apple Watch. Subjects were monitored for cardiac symptoms during ECG acquisition, and CIEDs were assessed for EMI. The collected ECGs were analyzed for interpretability, accuracy of heart rate measurement, and detection of non-capture events. RESULTS: Thirty-two patients (median age 14.0 years, IQR 9.9-16.6) were recruited. No adverse clinical events were identified. No EMI was detected during ECG acquisition, regardless of patient and CIED characteristics. Ninety-eight percent of acquired ECGs were interpretable. Both devices demonstrated excellent accuracy of heart rate measurement (ρ = 0.99) and a sensitivity of 100% for identifying ventricular non-capture events. CONCLUSIONS: KardiaMobile 6L and Apple Watch did not induce EMI in children and adolescents with CIEDs, enabling reliable heart rate measurement and accurate identification of ventricular non-captures on these smartphone-based portable heart monitors.