Chain of Survival
The AHA Chains of Survival describe the sequence of actions that give a cardiac-arrest victim the best chance of survival. There are separate chains for out-of-hospital and in-hospital arrest because the resources and first responders differ.
One Chain of Survival for everyone
The 2025 AHA Guidelines consolidated the four chains introduced in 2020 into a single six-link Chain of Survival that applies to adult and pediatric, in-hospital and out-of-hospital cardiac arrest: recognition and emergency activation, high-quality CPR, defibrillation, advanced resuscitation interventions, post–cardiac arrest care, and recovery. Prevention and preparedness — such as early warning systems and rapid response teams in hospitals — remain important but are named as the chain's missing link rather than a link of their own. The CPR link's symbol now shows compressions and breaths.
Why each link matters
The chain is only as strong as its weakest link: delayed recognition, delayed CPR or delayed defibrillation each lowers survival. The 2025 Guidelines call early, high-quality CPR and prompt defibrillation the most important interventions for adult cardiac arrest, and cite registry data in which each minute of delay to the first shock for witnessed VF was associated with about a 6% decrease in the probability of survival to discharge. That is why BLS providers recognize arrest quickly, start compressions at once, and get an AED on the chest as fast as possible.
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