Cardiac arrest occurs when the heart suddenly stops functioning. With no effective heartbeat, the brain and other vital organs are deprived of blood, leading to death within minutes.
Cardiac arrest is not a heart attack. The heart usually continues beating during a heart attack; however, cardiac arrest may occur as a result of a heart attack.
An estimated 250,000 to 450,000 Americans suffer cardiac arrest each year. Ninety-five percent die, often before receiving advanced medical attention.
Causes of Cardiac Arrest
Electrical signals in the heart synchronize heart function so that the heart beats properly and pumps blood through the body. Arrhythmias (abnormal heart rhythms) can interfere with normal heart function.
Ventricular fibrillation is a dangerous type of arrhythmia and the most common cause of cardiac arrest. It makes the lower chambers of the heart beat rapidly or chaotically. Other types of electrical problems that can lead to cardiac arrest include electrical signals that slow and stop, or the heart muscle's inability to respond to electrical signals.
Cardiac Arrest Risk Factors
Several factors can increase the risk for developing the electrical problems that can trigger cardiac arrest.
Cardiac arrest can also occur for no known reason.
Symptoms of Cardiac Arrest
People who suffer cardiac arrest lose consciousness and stop breathing. They have no pulse or blood pressure. An electrocardiogram shows either no electrical activity in the heart or a rhythm that is inadequate for heart function.
Treatment of Cardiac Arrest
When victims experience cardiac arrest, immediate treatment with a defibrillator (a device that delivers an electrical shock to the heart) can help restore the heart's normal rhythm. CPR (Cardiopulmonary resuscitation), when performed properly, can help provide adequate blood circulation until defibrillation and other emergency care is available.
Preventing Cardiac Arrest
Different strategies are available for preventing cardiac arrest, depending on a person's risk. Doctors may recommend that patients who are at very high risk for or have survived cardiac arrest undergo surgery to place an implantable cardioverter defibrillator under the skin of their abdomen or chest. These devices have tiny wires that connect to the heart and constantly monitor heart rhythms. When they detect dangerous arrhythmias, they deliver electrical shocks that help reestablish normal heart rhythm.
Doctors may also prescribe beta-blocker medications or perform procedures to address underlying coronary artery disease and other problems that can cause cardiac arrest.
Those who have no known risk can take these steps to help prevent cardiac arrest:
Get regular medical care
Follow a healthy diet, be physically active, lose extra pounds and quit smoking
Work with a doctor to control chronic conditions, such as diabetes, high blood pressure and high cholesterol
What can bystanders do?
The odds of surviving cardiac arrest decline dramatically during every minute that defibrillation and/or CPR is not provided. A bystander who sees someone who may be suffering cardiac arrest should call 911 immediately and, if possible, use an automated external defibrillator (AED). AEDs are portable defibrillator devices posted in many public areas. If an AED is not readily available, the bystander should perform CPR until the victim has access to defibrillation.
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