Pediatric Apple Watch Study

Specific Aim #1 - To determine the accuracy of Apple Watch ECG tracings heart rate in children. Specific Aim #2 - To determine if extended monitoring with the Apple Watch can identify arrhythmia events that were not detected by short term clinical monitoring.

Inclusion Criteria: * All pediatric patients age 6 - 21 years undergoing clinically indicated arrhythmia monitoring * Patients with developmental ability (as determined by patient and parents) to safely wear the Apple Watch and utilize the patient activated trigger buttons on both the clinical monitor and the Apple Watch. Exclusion Criteria: * Age \< 6 years. Those under 6 many not be able to safely use the watch and have the developmental ability (as gauged by clinician and parents) to utilize the trigger features on the watch and cardiac rhythm monitor. * Inability to effectively utilize the triggered features of the monitor or watch * Patients unable to utilize the Apple Watch.