October 11, 2017

Sudden Cardiac Arrest: How Does It Happen and What Can Be Done to Prevent It?

In sudden cardiac arrest, the heart is suddenly unable to pump blood effectively to the rest of the body, leading to loss of consciousness. Sudden cardiac arrest most often occurs in the setting of abnormal heart rhythms from a variety of causes (more on that below). If the heartbeat is not restored to a regular rhythm within minutes, the person will die. Sudden cardiac arrest is different from a heart attack, which happens when part of the heart muscle dies or is in the process of dying because blood flow to it has been blocked (although heart attacks are a common cause of sudden cardiac arrest).

What causes it?

Sudden cardiac arrest is often caused by a problem with the heart’s electrical system. In most cases, the heart’s rhythm is too fast and irregular, with the most feared rhythm being ventricular fibrillation (say “ven-TRICK-yuh-ler fib-ruh-LAY-shun”). The lower chambers of the heart (ventricles) quiver very fast and do not effectively pump blood. Sudden cardiac arrest often happens to people who didn’t know they had a heart problem.

Some other health problems can increase the chance of a deadly heart rhythm. They include:

  • Coronary artery disease
  • Congestive heart failure
  • Hypertrophic cardiomyopathy (say “hy-per-TROH-fik kar-dee-oh-my-AWP-uh-thee”), a condition, sometimes genetic or familial, where a particular area of the heart muscle is very thick
  • Advanced heart block (electrical conduction)
  • Valvular heart disease

How is it treated?

Health professionals, family or friends, and even strangers may be able to help a person right away who has sudden cardiac arrest. They can use CPR or a device called an automated external defibrillator (AED) to help restore a stable rhythm in the heart to save someone’s life. An AED can safely shock the heart back to a normal rhythm. AEDs are often available in airports, malls and other public places. To save a person, the device needs to be used within minutes of cardiac arrest. In the ambulance and hospital, the person will receive emergency care. This care keeps the heart and lungs working to prevent damage to the body due to lack of oxygen. Doctors will try to find the primary cause of the cardiac arrest to prevent another one from occurring again.

What you can do

A healthy lifestyle can help keep your heart strong and healthy. Try to:

  • Eat a heart-healthy diet. Eat more fruits and vegetables and other high-fiber foods.
  • Exercise for at least 30 minutes on most, if not all, days of the week.
  • Stay at a healthy weight. Lose weight if you need to.
  • Quit smoking, if you smoke. Smokers who quit cut their risk of coronary artery disease by half after one year.
  • Drink alcohol only in moderation. That means no more than two drinks a day for men, one drink a day for women.
  • Avoid using illegal drugs, such as stimulants like cocaine, ecstasy or methamphetamine. They can affect your heart’s rhythm.

If you take medicine for a heart problem, take it exactly as prescribed. Go to your doctor appointments, and call your doctor if you’re having problems.


Reviewed by Michael Chenier, MD, Mission Heart and Asheville Cardiology Associates

To learn more about your heart health, visit mission-health.org/heart.

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