cardiopulmonary resuscitation and emergency cardiac care, The International Liaison Committee on Resuscitation (ILCOR) echoed the concept in 1997. The links of the Chain of survival are described below. Early access to emergency medical care Ideally, someone must recognize an impending cardiac arrest or otherwise witness the cardiac arrest and activate the EMS system as early as possible with an immediate call to the emergency services. Unfortunately, many persons experiencing symptoms (for example, angina) that may lead to a cardiac arrest ignore these warning symptoms or, recognizing these warning symptoms correctly, fail to activate the EMS system, preferring to contact relatives instead (e.g., the elderly often contact their adult offspring rather than contact emergency services). Early CPR To be most effective, bystanders should provide CPR immediately after a patient collapses. In their 2015 guidelines, the American Heart Association re-emphasized the importance of more bystanders performing hands-only CPR until EMS personnel arrive because, at present, fewer than 40% of people who have an out-of-hospital cardiac arrest receive CPR from a bystander. The guidelines recommend lay rescuers start CPR on a person with presumed cardiac arrest because the overall risk of harm to patients from CPR is low, even if their heart hasn't stopped beating. Properly performed CPR can keep the heart in a shockable rhythm for 10–12 minutes longer. Early defibrillation Most adults who can be saved from cardiac arrest are in ventricular fibrillation or pulseless ventricular tachycardia, which means their heart has fallen out of rhythm. Early defibrillation is the link in the chain most likely to improve survival since defibrillation can help shock the heart back into a regular beat. Early, rapid defibrillation is considered the most important link in the chain of survival. Rapid defibrillation outside of the hospital improves the chances of survival by as much as 30%, and involves using an automated external defibrillator (AED) to shock the patient's heart. While CPR keeps blood flowing artificially, rapid defibrillation is the only way to restart the heart and reset it to a healthy rhythm. And while only 40% of adults experiencing cardiac arrest receive CPR, fewer than 12% receive shocks from an AED before EMS arrival. What is more, the chances of the patient's survival decrease by as much as 10% with every minute that they do not receive rapid defibrillation. AEDs are becoming more common in businesses, schools, and even the home as the public becomes more