Sudden Cardiac Arrest and Heart Attack - What's the Difference?

Sudden Cardiac Arrest vs. Heart Attack

Think that sudden cardiac arrest (SCA) and a heart attack are the same thing? Think again! While they are both conditions of the heart, they are actually very different in definition and cause. Since October is National Sudden Cardiac Arrest Awareness Month, let's take this opportunity to explain the differences.

Electrical System vs. Circulatory System

The main difference between sudden cardiac arrest (also called cardiac arrest) and heart attack can be explained by the system in which they occur. Here's the breakdown:

  • Cardiac arrest is an "electrical" problem. It occurs when the heart malfunctions and stops beating unexpectedly due to a problem in the electrical system.
  • A heart attack is a "circulation" problem. It occurs when blood flow to the heart is blocked due to a problem in the circulatory system.

What Happens During Cardiac Arrest?

Cardiac arrest is triggered by an electrical malfunction in the heart that causes an irregular heartbeat (arrhythmia). With its pumping action disrupted, the heart cannot pump blood to the brain, lungs and other organs. Seconds later, a person becomes unresponsive, is not breathing or is only gasping. Death occurs within minutes if the victim does not receive treatment.

What Happens During a Heart Attack?

Unlike with cardiac arrest, the heart usually does not stop beating during a heart attack. Instead, a blocked artery prevents oxygen-rich blood from reaching a section of the heart. If the blocked artery is not reopened quickly, the part of the heart normally nourished by that artery begins to die. Symptoms of a heart attack may be immediate, but most often they start slowly and persist for hours, days or even weeks. The longer the person goes without treatment, the greater the damage.

What's the Link?

Most heart attacks do not lead to cardiac arrest. But when SCA occurs, a heart attack is a common cause. That said, other conditions may also disrupt the heart's rhythm and lead to cardiac arrest.

What To Do: Call 9-1-1

Whether you suspect a heart attack or SCA, you should call 9-1-1 for emergency medical assistance. In the case of cardiac arrest, someone should begin performing CPR immediately while another person calls 9-1-1. When the EMS team arrives, they will apply defibrillation (a high energy shock) to try and restore a normal heartbeat. Every minute matters!

Source content for this article was provided by our partners at the American Heart Association. Learn more at

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