Sudden cardiac arrest (SCA) requires immediate treatment with a defibrillator, a device that sends an electrical shock to the heart. Defibrillation can restore a normal rhythm to a heart that is beating irregularly. To be effective, defibrillation must be provided within minutes of cardiac arrest. With every minute of delay in providing defibrillation, the chances of surviving SCA drop rapidly.
Police, emergency medical technicians, and other first responders are usually trained and equipped to use a defibrillator. The sooner 9–1–1 is called after a person experiences SCA, the sooner potentially lifesaving defibrillation can be provided.
Special defibrillators that untrained bystanders can use in an emergency are becoming more available in some public places, like airports, office buildings, and shopping centers. These devices are called automated external defibrillators (AEDs). To prevent delivering a shock to someone who may have fainted but is not having a SCA, AEDs are programmed to deliver a shock only if the computer detects a dangerously abnormal heart rhythm, such as ventricular fibrillation.
Cardiopulmonary resuscitation (CPR) should be given to a person having SCA until defibrillation can be provided.
A person who survives SCA is usually admitted to the hospital for observation and treatment. In the hospital, the heart is monitored closely, medicines may be given to try to reduce the chance of another SCA, and tests are performed to identify the cause of the SCA. If coronary artery disease is detected, the person may undergo a procedure called angioplasty to restore blood flow through blocked coronary arteries.
Often, a device called an implantable cardioverter defibrillator (ICD) will be surgically placed under the skin. An ICD continuously monitors the heart for dangerous rhythms. If SCA or another dangerous rhythm is detected, the ICD immediately delivers an electric shock to restore a normal rhythm.
The National Heart, Lung and Blood Institute (NHLBI), National Institutes of Health, "Heart Failure" section, provides leadership for a national program in diseases of the heart, blood vessels, lung, and blood; blood resources; and sleep disorders.