Sudden cardiac arrest is the leading killer of modern times. Annually, 100,000 persons die from sudden cardiac arrest. The number of deaths from sudden cardiac arrest remain needlessly high. Due to advancements in Emergency Medical Services, like 911 Access and Automatic Defibrillation, the chances of surviving a sudden cardiac arrest are on the increase.

The "Chain of Survival" describes the links needed to coincide to successfully resuscitate a person who experience sudden cardiac arrest. The concept of Chain of Survival has been introduced and supported by the American Heart Association. The links of the Chain of Survival are:

• Early Access
• Early CPR
• Early Defibrillation
• Early Advanced Life Support

The public is important for successful completion of the Chain of Survival. Early Access means prompt recognition of a possible cardiac problem and immediate access to Emergency Medical Services. The best outcome happens by calling 911 when symptoms of a heart attack begin. In the event of a cardiac arrest, Early CPR is just as important as access. By manually pumping for the heart and moving air within in the lungs, CPR spares vital organs from being starved from oxygen. Properly performed CPR will extend the time frame that Early Defibrillation is successful. This makes the victims heart respond to defibrillation and correct the electrical disturbance. The final link in the chain is Early Advanced Life Support. The chances of survival from a cardiac arrest are best when the links of the chain coincide.

Defibrillation is simply applying an electrical shock to the heart, which aids the heart to resume a normal pumping action. The heart will enter a irritable phase at the beginning of cardiac arrest called Ventricular Fibrillation. Fibrillation means "to quiver". Essentially, the heart is quivering inside of the chest during Ventricular Fibrillation. Random electrical impulses cause the heart muscle to contract in a disorganized pattern, much opposite from the organized conduction used to pump blood to the body. Only by defibrillation, the heart is allowed to reorganize the electrical impulses into proper conduction. The longer a victim must wait before defibrillation, lessens the chance of defibrillation being effective. .

Because Defibrillation must be performed quickly after sudden cardiac arrest occurs, this skill has been placed in the hands of first responders. First Responders use a machine called an Automatic External Defibrillator (AED). The AED is computerized machine that automatically determine the hearts electrical rhythm and delivers a shock if needed. The machine will record the electrical impulses along with the operation of the machine on a cassette tape used to gauge the machines effectiveness. Launched in 1987, all First Responder departments in Johnson County are trained to used an Automatic External Defibrillator.