Key Points

• Sudden cardiac arrest (SCA) is when the heart suddenly and unexpectedly stops beating. This is often because of a problem with the heart's electrical system.
• SCA is not the same thing as a heart attack, although it may happen during recovery from a heart attack.
• The first sign of SCA is usually sudden loss of consciousness.
• Ninety-five percent of people who have SCA die from it, most within minutes.
• Several factors can cause electrical problems that trigger SCA, including coronary artery disease, physical stress, inherited disorders, and structural changes in the heart.
• People with heart disease have a greater chance of having SCA. But most cases occur in people who appear healthy and have no known heart disease or other risk factors for SCA.
• SCA occurs most often in adults in their mid-thirties to mid-forties. It affects men twice as often as women. SCA rarely occurs in children (although children with certain inherited heart conditions are at increased risk).
• Several tests can help show if people have a greater chance for having SCA. These tests are EKG, echocardiogram, MUGA test, magnetic resonance imaging (MRI) heart scan, cardiac catheterization, and electrophysiology study.
• SCA requires immediate treatment with a device called a defibrillator, which delivers an electrical shock to the heart. Successful defibrillation restores normal rhythm to the heart.
• Defibrillation must be provided within minutes after SCA to avoid permanent damage to the body and brain and to prevent death. With every minute of delay in providing defibrillation, the chances of surviving SCA drop rapidly.
• People experiencing SCA should be given cardiopulmonary resuscitation (CPR) until they can be treated with a defibrillator.
• Special defibrillators called automated external defibrillators (AEDs) can be used by untrained bystanders in an emergency. AEDs are becoming increasingly available at public places, such as airports, office building, and shopping centers.
• People who survive SCA may need an implantable cardioverter defibrillator to help prevent death if another SCA happens.
• Beta blocker drugs also help reduce the chance of death from SCA in people with known heart disease.
• Heart healthy lifestyle choices may lower people's chances for SCA.