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Cardiac Arrest Causes

Cardiac arrest occurs when your heart stops suddenly. With the pumping action of your heart disrupted, blood is unable to flow to vital organs, resulting in loss of breathing and consciousness. Here is a comprehensive overview of the causes and risk factors that increase your chances for cardiac arrest.


The most common cause of cardiac arrest is an irregular heartbeat, also known as an arrhythmia. When something goes wrong with the flow of electric impulses through your heart, an arrhythmia develops. This can cause your heart to beat too fast, too slow, or in an otherwise irregular way. Although often harmless, some types of arrhythmia can be serious and fatal.
The type of arrhythmia that is most commonly the cause of cardiac arrest is known as ventricular fibrillation. Ventricular fibrillation occurs when your heart’s electrical system becomes disrupted and the lower chambers of your heart contract in a rapid, abnormal way. Your heart then stops pumping or pumps very little blood, and cardiac arrest occurs. 

Coronary Artery Disease

With coronary artery disease, blood flow to your heart is reduced due to clogged arteries, making it harder for your heart to receive electrical impulses normally. Cardiac arrest most commonly occurs in people who have coronary artery disease.

Heart Attack

A heart attack can cause ventricular fibrillation and cardiac arrest. Scar tissue can also be left behind from a heart attack—irregular heartbeats are known to develop due to electrical short circuits around the scar tissue.

Enlarged Heart

Also referred to as cardiomyopathy, an enlarged heart occurs when your heart’s muscular walls stretch and grow or thicken. This condition usually leads to damaged heart tissue and an increased risk for arrhythmias—thus, an increased risk for cardiac arrest as well.

Congenital Heart Disease

If cardiac arrest occurs in adolescents or children, it may  be because of a heart condition that was present at birth—this is known as congenital heart disease. Even if you have undergone corrective surgery for the birth defect, you still have an increased risk of cardiac arrest.

Cardiac Arrest Risk Factors

Cardiac arrest is often associated with coronary artery disease, because the same factors that increase your risk for coronary artery disease also increase your risk for cardiac arrest. These factors include:

  • A family history of coronary artery disease
  • Smoking
  • High blood pressure
  • High cholesterol
  • Obesity
  • Diabetes
  • Excessive alcohol intake
  • A past episode of cardiac arrest
  • A past heart attack
  • Being male
  • Using illegal drugs (specifically cocaine or amphetamines)
Last Updated: April 25, 2016