Fernando SM, et al. - Quality of bystander cardiopulmonary resuscitation (CPR) provided during out-of-hospital cardiac arrest (OHCA) was determined using CPR quality data stored by Automated External Defibrillators (AEDs). Researchers identified 100 cases of OHCA of presumed cardiac etiology involving bystander CPR and with corresponding AED data. Findings revealed that high-quality CPR was performed by the bystanders, with strong adherence rates to existing Resuscitation Guidelines. High-quality CPR is maintained over the first five minutes of resuscitation but was lowest in the first minute.