Cardiac arrest is the complete stop of the heart beat, which is the pumping of blood through the arteries. Many heart conditions are chronic and, under a physician’s care, can be successfully managed. Even a life-threatening emergency such as a heart attack offers a short period of time in which treatment can save the person’s life. However, cardiac arrest must be treated immediately to avoid losing the patient. This is because the heart has a markedly abnormal rhythm, most often from ventricular fibrillation. Other causes include ventricular tachycardia and asystole. Unfortunately, most people cannot get help fast enough. Those who survive cardiac arrest are said to have lived through an "aborted" sudden cardiac death.

Although cardiac arrest often happens without warning, the event rarely takes place in a normal heart unless other factors (drug use and trauma) are present. Otherwise, there is almost always underlying heart disease heart damage maybe from a previous heart attack that may progress to the point where a critical situation develops.
Therefore, people should make lifestyle changes to prevent the conditions that could trigger cardiac arrest. Experts also recommend medical treatment of those underlying conditions, which may involve taking medications and/or having surgery.