Sudden Cardiac Death
Provided by AmericanHeart.org

AHA Scientific Position

Sudden death from cardiac arrest is a major health problem that's received much less publicity than heart attack. The American Heart Association supports implementing the "chain of survival" to rescue people who suffer a cardiac arrest in the community. The adult chain consists of

• Early Access to Medical Care (calling 9-1-1 immediately)
• Early CPR
• Early Defibrillation
• Early Advanced Care

What is sudden cardiac death?

Sudden cardiac death (also called sudden arrest) is death resulting from an abrupt loss of heart function (cardiac arrest). The victim may or may not have diagnosed heart disease. The time and mode of death are unexpected . It occurs within minutes after symptoms appear. The most common underlying reason for patients to die suddenly from cardiac arrest is coronary heart disease (fatty buildups in the arteries that supply blood to the heart muscle).

About 340,000 people a year die of coronary heart disease without being hospitalized or admitted to an emergency room. That's about half of all deaths from CHD - more than 930 Americans each day. Most of these are sudden deaths caused by cardiac arrest.

What causes sudden cardiac death?

All known heart diseases can lead to cardiac arrest and sudden cardiac death. Most of the cardiac arrests that lead to sudden death occur when the electrical impulses in the diseased heart become rapid (ventricular tachycardia) or chaotic (ventricular fibrillation) or both. This irregular heart rhythm (arrhythmia) causes the heart to suddenly stop beating. Some cardiac arrests are due to extreme slowing of the heart. This is called bradycardia.

In 90 percent of adult victims of sudden cardiac death, two or more major coronary arteries are narrowed by fatty buildups. 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 physical or athletic activity often acts as a trigger for 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.

The term "massive heart attack" is often wrongly used in the media to describe sudden death. The term "heart attack" refers to death of heart muscle tissue due to the loss of blood supply, not necessarily resulting in a cardiac arrest or the death of the heart attack victim. A heart attack may cause cardiac arrest and sudden cardiac death, but the terms aren't synonymous.

Can the cardiac arrest that causes sudden death be reversed?

Brain death and permanent death start to occur in just four to six minutes after someone experiences cardiac arrest. Cardiac arrest is reversible in most victims if it's treated within a few minutes with an electric shock to the heart to restore a normal heartbeat. This process is called defibrillation. A victim's chances of survival are reduced by 7 to 10 percent with every minute that passes without defibrillation. Few attempts at resuscitation succeed after 10 minutes. If someone becomes unconscious, call 9-1-1 immediately.  They may be suffering from sudden cardiac arrest.

What are treatments for survivors?

If a cardiac arrest was due to ventricular tachycardia or ventricular fibrillation, survivors are at risk for another arrest, especially if they have underlying heart disease.

Survivors of cardiac arrest must have all causes corrected to prevent future episodes. Possible causes include myocardial ischemia (inadequate blood flow to the heart muscle), arrhythmia (abnormal heart rhythm), etc.

Possible tests and treatments include

• cardiac catheterization 
• electrophysiologic tests
• coronary artery bypass surgery
• balloon angioplasty or PTCA
• antiarrhythmic medicine
• implantable cardioverter / defibrillator 
• implantable pacemaker
• heart transplant

Provided by AmericanHeart.org

 

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