When Do Smartwatch Heart Rate Concerns in Children Indicate Arrhythmia?

OBJECTIVE: To determine the incidence and predictors of true arrhythmia in pediatric patients presenting with concerns about smartwatch cardiac data. STUDY DESIGN: Single-center, retrospective cohort study of children aged 10-18 years who had presented to a pediatric cardiology clinic between January 2018 and December 2021 with concerns related to smartwatch cardiac data. The primary study outcome was diagnosis of arrhythmia based on clinical evaluation or documentation of arrhythmia by clinical testing. RESULTS: There were 126 patients (mean age 15.6 ± 2.4 years) who presented with a smartwatch-based rhythm concern, with tachycardia in 89%. In all, 19 of 126 (15%) patients were diagnosed with true arrhythmia. The odds of a true arrhythmia diagnosis with symptoms vs no symptoms were 3.2 (95% CI 0.7-14.5), and with heart rate (HR) ≥190 beats/min vs HR <190 beats/min, it was 14.3 (95% CI 3.8-52.8). The positive predictive value of HR ≥190 beats/min and symptoms together to predict arrhythmia was only 39% (95% CI 28-52). The negative predictive value for arrhythmia having neither symptoms nor HR >190 was 95% (95% CI 75-99). CONCLUSION: The likelihood of a true arrhythmia in pediatric patients presenting with a smartwatch-based HR concern was low. Rarely, smartwatch electrograms or trend data were sufficient for arrhythmia diagnosis.

Detection of Tachyarrhythmias in a Large Cohort of Infants Using Direct-to-Consumer Heart Rate Monitoring.

OBJECTIVE: Current estimates of the incidence of tachyarrhythmias in infants rely on clinical documentation and may not reflect the true rate in the general population. Our aim was to describe the epidemiology of tachyarrhythmia detected in a large cohort of infants using direct-to-consumer heart rate (HR) monitoring. STUDY DESIGN: Data were collected from Owlet Smart Sock devices used in infants in the US with birthdates between February 2017 and February 2019. We queried the HR data for episodes of tachyarrhythmia (HR of ≥240 bpm for >60 seconds). RESULTS: The study included 100 949 infants (50.8% male) monitored for more than 200 million total hours. We identified 5070 episodes of tachyarrhythmia in 2508 infants. The cumulative incidence of tachyarrhythmia in our cohort was 2.5% over the first year of life. The median age at the time of the first episode of tachyarrhythmia was 36 days (range, 1-358 days). Tachyarrhythmia was more common in infants with congenital heart disease (4.0% vs 2.4%; P = .015) and in females (2.7% vs 2.0%; P < .001). The median length of an episode was 7.3 minutes (range, 60 seconds to 5.4 hours) and the probability of an episode lasting longer than 45 minutes was 16.8% (95% CI, 15.4%-18.3%). CONCLUSIONS: We found the cumulative incidence of tachyarrhythmia among infants using direct-to-consumer HR monitors to be higher than previously reported in studies relying on clinical diagnosis. This finding may represent previously undetected subclinical disease in young infants, the significance of which remains uncertain. Clinicians should be prepared to discuss these events with parents.

Novel ryanodine receptor 2 mutation associated with a severe phenotype of catecholaminergic polymorphic ventricular tachycardia.

An adolescent girl with a history of anxiety associated seizure-like episodes was ultimately diagnosed with catecholaminergic polymorphic ventricular tachycardia. She tested positive for a novel mutation of the ryanodine receptor. The report underscores how genetic arrhythmia syndromes may be mistaken for neurologic disorders.