Barry OM, et al. - Researchers determined the frequency of arrhythmias during pediatric exercise stress tests (ESTs) and assessed criteria to recognize patients at risk of clinically important arrhythmias. They conducted a retrospective review of ESTs from 2013 to 2015. In a high-volume pediatric cardiology program, there was a common prevalence of self-terminating arrhythmias, but dangerous arrhythmias rarely occurred during ESTs. Identification of all patients with the most serious events was successfully done via pre-defined high-risk criteria; a low risk for arrhythmias was predicted by the absence of any criteria that required test termination. Informed choices regarding supervision of ESTs could be made with the aid of these data.