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Sudden cardiac arrest (SCA)

  • Sudden cardiac arrest

    For more about sudden cardiac arrest, call 651-241 4470 or email

    Sudden cardiac arrest (SCA) is usually caused by an electrical malfunction of the heart called ventricular fibrillation.

    Ventricular fibrillation causes a quivering of the heart muscle that makes it unable to pump blood through the body. Once the blood stops circulating, a person quickly loses consciousness and the ability to breathe, and will die without effective treatment.

    More people die of sudden cardiac arrest than lung cancer, breast cancer and AIDS combined.  

  • What is the treatment for sudden cardiac arrest?

    The only effective treatment is an electric shock to the heart called defibrillation. The electrical current can interrupt ventricular fibrillation and allow the heart's normal rhythm to regain control.

    Defibrillation is most effective if it is applied within three to five minutes into sudden cardiac arrest. With each passing minute, the likelihood of recovery drops about 10 percent. After 10 minutes, one's chance of survival falls to about 2 percent.

    While defibrillation with an automated external defibrillator (AED) is important, we also encourage immediate cardiopulmonary resuscitation (CPR). If you are hesitant or unwilling to do mouth-to-mouth breathing, immediately begin "hands only" or "compression only" CPR.  This can improve the success of the AED and improve chances of survival.

    People who survive sudden cardiac arrest have a 30 to 50 percent chance of having a second one. That is why they are often referred to an electrophysiologist, a heart rhythm specialist, to receive an implantable cardioverter-defibrillator (ICD).

    How common is sudden cardiac arrest?

    Sudden cardiac arrest (SCA) can happen to anyone, anywhere, any time. Every day in the United States, it strikes about 1,000 people. Tragically, almost all of them die, making SCA a leading causes of death. In fact, some experts commonly refer to it as sudden cardiac death.

    Is sudden cardiac arrest the same as a heart attack?


    Sudden cardiac arrest is usually caused by ventricular fibrillation, an electrical malfunction of the heart.

    A heart attack occurs when plaque or clots block blood flow to the heart. Although the heart continues to beat, irreversible damage to the heart muscle begins within 15 to 30 minutes. The longer the blood flow is interrupted, the more extensive the damage done. Treatment for heart attack includes angioplasty - using a tiny balloon to widen blocked vessels - and 'clot-busting' drugs known as thrombolytics.

  • Source: American Heart Association; Darren Boser, Lance Stephenson, A Heart for the Community: Public Access Defibrillation and the HeartSave Awareness Program, Access Medical Incorporated 2003
    Reviewed by: Charles Lick, MD, medical director, Allina Health Emergency Medical Services
    First published: 05/06/2004
    Last reviewed: 02/19/2007