This document provides information about cardiac arrest and chest compression-only CPR. It discusses that cardiac arrest can happen to anyone at any age, and that chest compression-only CPR is effective for cardiac arrest until emergency services arrive. The key points are that chest compressions alone are sufficient to circulate blood to the brain and heart when performed at a rate of 100 per minute with a depth of at least 2 inches. Bystander CPR, even just chest compressions, can double or triple a person's chance of survival from cardiac arrest.