What Is Sudden Cardiac Arrest? Everything to Know

Medically Reviewed By Uzochukwu Ibe, MD, MPH

Sudden cardiac arrest happens when the heart unexpectedly stops beating. It is a medical emergency that requires immediate treatment, including using an automatic external defibrillator and performing CPR. An electrical malfunction in the heart can cause irregular heartbeats or arrhythmias. When an arrhythmia prevents the heart from pumping blood, this can cause sudden cardiac arrest.

Around 9 out of 10 people who experience sudden cardiac arrest outside the hospital will die, according to the National Heart, Lung, and Blood Institute. When this happens, this is called sudden cardiac death.

It is important to be aware of the symptoms of sudden cardiac arrest and how to treat a person experiencing sudden cardiac arrest.

What are the symptoms of sudden cardiac arrest?

A woman has her hand on her chest.
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In most cases, according to MedlinePlus, the first symptom of sudden cardiac arrest is fainting or loss of consciousness. This happens once the heart stops beating.

Other symptoms a person may display when they experience sudden cardiac arrest include:

  • ineffective breathing
  • either no pulse or breathing
  • unresponsiveness to shaking or shouting

Early symptoms

Some people experience symptoms in the hour before they experience sudden cardiac arrest. These can include:

What should I do if somebody is experiencing sudden cardiac arrest?

Call the emergency services if somebody is in sudden cardiac arrest. It is a medical emergency, and immediate treatment is crucial.

After you call the emergency services, check to see if there is an automatic external defibrillator (AED) available. Most AEDs include clear, easy-to-follow instructions for using them. Learn more about defibrillation.

After using the AED, or if no AED is available, begin CPR. This includes hands-only chest compressions. The American Heart Association recommends doing this to the beat of the song “Stayin’ Alive,” which they say can double or triple a person’s chance of surviving sudden cardiac arrest.

Find out more about how to perform CPR.

What are the treatments after sudden cardiac arrest?

After receiving emergency medical attention for sudden cardiac arrest, you may receive treatment in the hospital.

Possible treatments you may receive in the hospital include:

  • oxygen therapy, which can help you get enough oxygen into your lungs while you recover
  • targeted temperature management, which involves protecting the brain by lowering your body temperature with cool pads
  • extracorporeal membrane oxygenation, during which blood pumps through an artificial lung to add oxygen and remove the carbon dioxide before the blood returns to your body

You may require other treatments depending on the cause of sudden cardiac arrest. This can include medications and surgery.

What causes sudden cardiac arrest?

A person may experience cardiac arrest from almost any heart condition, according to the American Heart Association.

Ventricular fibrillation is a type of arrhythmia that can cause sudden cardiac arrest. Ventricular fibrillation happens when the electrical signals cause the ventricles in your heart to quiver instead of pumping as they usually should.

Learn more about ventricular fibrillation.

Risk factors

There are certain factors that increase your risk of ventricular fibrillation or sudden cardiac arrest. These include:

Learn more about causes and symptoms of heart conditions.

Triggers

There are certain factors that may trigger sudden cardiac arrest. These include:

  • physical exercise or exertion, which accounts for around 2 in 20 cardiac arrests
  • heavy alcohol use, which accounts for up to 3 in 20 cardiac arrests
  • heavily drinking coffee, particularly if you do not regularly drink coffee
  • severe emotional distress within the last month
  • the flu within the last month
  • recent use of cannabis, amphetamines, or cocaine

Contact your doctor if you have concerns about the risk factors or triggers of sudden cardiac arrest.

When should I see a doctor?

Get immediate medical help if somebody is in sudden cardiac arrest. Call the emergency services before using any available AED and performing CPR.

Contact your doctor if you have concerns about your heart health. Also, contact your doctor if you recently experienced sudden cardiac arrest and have questions about any treatments they put in place for you.

How do doctors diagnose the cause of sudden cardiac arrest?

At the time of the sudden cardiac arrest, a first responder will check for a pulse. They will then use an AED and carry out CPR.

Once you are in the hospital, your doctor will carry out a physical examination and order tests to help with confirming the cause of sudden cardiac arrest.

Tests they may order include:

Your doctor may also carry out genetic testing on both you and your family members. This is because certain genetic changes can increase your risk of cardiac arrest.

Your doctor can explain the tests that they order and answer any questions you may have.

What are the complications of sudden cardiac arrest?

People who survive sudden cardiac arrest are likely to experience injury to the brain or nervous system, according to the Centers for Disease Control and Prevention.

Other possible complications of sudden cardiac arrest include:

If you experienced sudden cardiac arrest and have psychological distress, contact your doctor for advice. They can refer you to a mental health specialist.

Can I prevent sudden cardiac arrest?

Following your doctor’s treatment plan for any heart condition and making sure you attend your appointments can help you to stay on top of your heart health. This can help to reduce your risk of sudden cardiac arrest.

Taking steps to look after your heart can also help reduce your risk of sudden cardiac arrest. These steps can include:

  • eating heart-healthy foods
  • maintaining a moderate weight
  • getting regular exercise
  • managing stress
  • quitting smoking if you smoke

Contact your doctor for more advice about ways you can look after your heart.

Summary

Sudden cardiac arrest is a medical emergency that occurs when the heart unexpectedly stops beating.

It is important to get immediate medical help if somebody goes into sudden cardiac arrest. Then, use any available AED and perform CPR.

Almost any heart condition can cause sudden cardiac arrest. Following your treatment plan, attending your appointments, and looking after your heart health can help reduce your risk of cardiac arrest.

Contact your doctor if you have concerns about your heart health. They can carry out tests to confirm the cause of your symptoms and advise on any treatments they recommend.

Medical Reviewer: Uzochukwu Ibe, MD, MPH
Last Review Date: 2022 Oct 12
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