What is sudden cardiac arrest?

Sudden cardiac arrest means the heart has suddenly and unexpectedly stopped beating. It stops pumping blood to the brain and the rest of the body. Without immediate treatment, it causes death.

What is the cause?

Sudden cardiac arrest is caused by an abnormal heart rhythm that is too fast, too slow, or not regular. Abnormal heart rhythms can be caused by several conditions. Examples of these conditions are:

• Coronary artery disease. A blocked blood vessel may affect the part of the heart that carries the signal for the heart to beat. This kind of blockage is especially dangerous if the heart is already scarred from a heart attack.
• Cardiomyopathy. Cardiomyopathy is a disease of the heart muscle. The heart muscle may be weakened or thickened. This makes it harder for the heart to pump enough blood through all of the body.
• Long Q-T syndrome (LQTS). This is a form of heart disease that some people are born with. It sometimes causes heart rhythm problems, particularly when there is emotional or physical stress. LQTS can appear at any age but often happens in children and young adults.

Several things make sudden cardiac arrest or death more likely if you have heart disease.

• If you do not exercise regularly and then engage in heavy physical activity, you have a higher risk of sudden cardiac death.
• Stress may cause cardiac arrest if you have heart disease.
• Some medicines can cause an irregular heartbeat that is life threatening.
• Some types of illegal drug use can also cause sudden cardiac death.

What are the symptoms?

The sudden and severe symptoms of cardiac arrest are:

• Fainting (loss of consciousness)
• No pulse
• No breathing

Before fainting, symptoms may include:

• Dizziness
• Chest pain
• Trouble breathing
• Nausea or vomiting

In some cases, cardiac arrest may happen with no warning.

How is it treated?

When cardiac arrest happens, lack of blood flow to the brain and other parts of the body can cause severe damage and death. The only treatment is to get the heart beating normally again before there is severe damage.

Call 911 FIRST. The best thing you can do for someone in cardiac arrest is to call for medical help right away. Start CPR (cardiopulmonary resuscitation) if you have been trained in it. CPR can keep blood flowing to the brain and other organs until a normal heart rhythm is restored. You may be able to use an automatic external defibrillator (AED) to get the heart to start pumping normally again. AEDs are available in many public places and on some airplanes. They are designed to be used by people without medical training. AEDs shock the heart and can change an abnormal rhythm back to a normal rhythm.

How can I help prevent sudden cardiac arrest?

The first step is to see if you have any medical problems that increase your risk of sudden cardiac arrest. Often these conditions can be treated with medicines or a pacemaker. It is important to make healthy lifestyle changes that prevent coronary artery disease, and to treat conditions that increase your risk for cardiac arrest.

If you have had a heart attack, follow the treatment prescribed by your healthcare provider.

People at highest risk for cardiac arrest may need an implantable cardioverter defibrillator (ICD). ICDs detect abnormal heart rhythms and shock the heart back to a normal rhythm. For other people, medicines such as beta blockers can reduce the risk of sudden cardiac death.