Heart Attack or Sudden Cardiac Arrest—How They Differ and What to Do

Senior woman clutching chest

From the American Heart Association

People often use these terms interchangeably, but they are not the same thing. A heart attack is when blood flow to the heart is blocked, and sudden cardiac arrest is when the heart malfunctions and suddenly stops beating. A heart attack is a “circulation” problem and sudden cardiac arrest is an “electrical” problem.

What is a heart attack?

A heart attack occurs when 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. The longer a person goes without treatment, the greater the damage.

Symptoms of a heart attack may be immediate and intense. More often, though, symptoms start slowly and persist for hours, days or weeks before a heart attack. Unlike with sudden cardiac arrest, the heart usually does not stop beating during a heart attack.

What is cardiac arrest?

Sudden cardiac arrest occurs often without warning. It 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 loses consciousness and has no pulse. Death occurs within minutes if the victim does not receive treatment.

What is the link?

These two distinct heart conditions are linked. Sudden cardiac arrest can occur after a heart attack, or during recovery. Heart attacks increase the risk for sudden cardiac arrest. Most heart attacks do not lead to sudden cardiac arrest. But when sudden cardiac arrest occurs, heart attack is a common cause.

Other heart conditions may also disrupt the heart’s rhythm and lead to sudden cardiac arrest. These include a thickened heart muscle (cardiomyopathy), heart failure, arrhythmias, ventricular fibrillation, and long Q-T syndrome.

What to do: Heart Attack

Even if you’re not sure it’s a heart attack, call 911 or your emergency response number. Every minute matters! It’s best to call EMS to get to the emergency room right away. Emergency medical services staff can begin treatment when they arrive — up to an hour sooner than if someone gets to the hospital by car. EMS staff are also trained to revive someone whose heart has stopped. Patients with chest pain who arrive by ambulance usually receive faster treatment at the hospital, too.

What to do: Sudden Cardiac Arrest

Cardiac arrest can strike without warning and is reversible in most victims if it’s treated within a few minutes. Here are the signs:

Sudden loss of responsiveness: The person doesn’t respond, even if you tap him or her hard on the shoulders, or ask loudly if he or she is OK. The person doesn’t move, speak, blink or otherwise react.

No normal breathing: The person isn’t breathing or is only gasping for air.

If you have tried and failed to get the person to respond, and you think the person may be suffering cardiac arrest, here’s what to do:

  • Yell for help: Tell someone nearby to call 911 or your emergency response number. Ask that person or another bystander to bring you an AED (automated external defibrillator), if there’s one on hand. Tell them to hurry—time is of the essence. If you’re alone with an adult who has signs of cardiac arrest, call 911 and get an AED (if one is available).
  • Check breathing: If the person isn’t breathing or is only gasping, administer CPR.
  • Give CPR: Push down hard and fast at least two inches at a rate of 100 to 120 pushes a minute in the center of the chest, allowing the chest to come back up to its normal position after each push.
  • Use an AED: Use the automated external defibrillator as soon as it arrives. Turn it on and follow the prompts.
  • Keep pushing: Continue administering CPR until the person starts to breathe or move, or until someone with more advanced training takes over, such as an EMS provider.

Common heart attack warning signs

  • Shortness of breath
  • Jaw, neck or back pain
  • Pain or discomfort in chest
  • Nausea, vomiting or light-headedness
  • Discomfort or pain in arm or shouder

Note for women: As with men, women’s most common heart attack symptom is chest pain or discomfort. But women are somewhat more likely than men to experience some of the other common symptoms, particularly shortness of breath, nausea/vomiting, back or jaw pain, fainting, indigestion and extreme fatigue.

Learn more about how to administer CPR and find additional information about heart conditions that can lead to heart attack or cardiac arrest at the American Heart Association’s website: heart.org.