Strategies for Defibrillation During Out-of-Hospital Cardiac Arrest

Inclusion Criteria: 1. Out-of-hospital cardiac arrest 2. Age ≥ 18 years 3. ≥ 1 manual defibrillation attempt by emergency medical services 4. Shockable rhythm as the last known rhythm 5. Two manual defibrillators present on-site Exclusion Criteria: 1. Blunt trauma, penetrating trauma, or burn injury suspected to be the cause of the cardiac arrest 2. Prior enrollment in the trial 3. Posterior pad placement not deemed possible by on-site clinician