Sudden death from cardiac arrest is a major health problem that has received much less publicity than heart attack. The American Heart Association offers these statistics as part of our public awareness campaign to increase cardiac arrest survival across the United States.

Although the direct medical costs are much less than for lingering illnesses, the economic and social impacts of sudden death from cardiac arrest are huge. Sudden death occurs on average at about 60 years of age, claims many people during their most productive years, and devastates unprepared families.

Sudden death (also called sudden cardiac death) occurs when the heart stops abruptly (cardiac arrest). The victim may or may not have diagnosed heart disease. Death can occur within minutes after symptoms appear, or there may be no symptoms before collapse. The most common underlying reason that patients die suddenly from cardiac arrest is coronary heart disease.

In 90 percent of adult victims of sudden death, two or more major coronary arteries are narrowed by atherosclerosis. Scarring from a prior heart attack is found in two-thirds of victims. When sudden death occurs in young adults, other heart abnormalities are more likely causes. Adrenaline released during intense athletic or physical activity often triggers sudden death when these abnormalities are present. Under certain conditions, various heart medications and other drugs -- as well as illegal drug abuse -- can lead to abnormal heart rhythms that cause sudden death.

Cardiac arrest occurs suddenly and dramatically. It's also sometimes called sudden cardiac arrest or unexpected cardiac arrest. Most known heart diseases can lead to cardiac arrest and sudden death. Most of the cardiac arrests that lead to sudden death occur when the electrical impulses in the heart become rapid (ventricular tachycardia) or chaotic (ventricular fibrillation) or both. This irregular heart rhythm causes the heart to suddenly stop beating. A small number of cardiac arrests are caused by extreme slowing of the heart (bradycardia).

No statistics are available for the exact number of cardiac arrests that occur each year. However, about 310,000 people a year die of coronary heart disease without being hospitalized. That's about half of all deaths from CHD -- about 850 Americans each day. Most of these are sudden deaths caused by cardiac arrest. Other factors besides heart disease and heart attack can cause cardiac arrest. They include respiratory arrest, electrocution, drowning, choking or trauma. Cardiac arrest also can occur without any known cause.

Brain death and permanent death start to occur in just 4 to 6 minutes after someone experiences cardiac arrest. Cardiac arrest can be reversed in most victims if it's treated with immediate CPR and an electric shock to the heart within 7 to 10 minutes. CPR consists of mouth-to-mouth breathing and chest compressions. The shock eliminates the abnormal rhythm and allows the heart's normal rhythm to resume. This process is called defibrillation.

A victim's chances of survival are reduced by 7-10 percent with every minute that passes without treatment. Few resuscitation attempts succeed after 10 minutes have elapsed. It's estimated that more than 95 percent of cardiac arrest victims die before reaching the hospital. In cities where defibrillation is provided within 5 to 7 minutes, the survival rate from cardiac arrest is as high as 49 percent.

Early CPR and rapid defibrillation combined with early advanced care can produce high long-term survival rates for witnessed cardiac arrest. In one case, automated external defibrillators (AEDs) were mounted a distance of one minute apart in plain view at Chicago's O'Hare and Midway Airports in June 1999. In the first 10 months, 14 cardiac arrests occurred with 12 of the 14 victims in ventricular fibrillation. Nine of the 14 victims (64 percent) were revived with an AED and had no brain damage.
If bystander CPR was more consistently started, AEDs were more widely available, and the survival rate from cardiac arrest was increased to 20 percent, at least 40,000 lives could be saved each year. The American Heart Association urges the public to
be prepared for cardiac emergencies:

• Know the warning signs of heart attack and cardiac arrest.  During cardiac arrest, a victim becomes unresponsive, stops normal breathing, and loses pulse or other signs of circulation. (See heart attack warning signs.)
  
• Call 9-1-1  immediately to access the emergency medical services (EMS) if you see any warning signs of heart attack or if someone collapses suddenly and is unresponsive.
  
• Begin cardiopulmonary resuscitation (CPR) immediately. This will help keep the cardiac arrest victim alive until emergency help arrives. CPR keeps blood flowing to the heart and brain until defibrillation can be provided.
  

Death from cardiac arrest isn't inevitable. If more people react quickly by calling 9-1-1 and performing CPR, more lives can be saved. In the remainder of this booklet, statistics relating to sudden death and cardiac arrest are highlighted in pink.