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Sudden Cardiac Arrest Vs Heart Attack: What’s the Difference?

Sudden Cardiac Arrest Vs Heart Attack: What’s the Difference?

April 22, 2021 | Last Updated: July 27, 2021
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Despite the fact that “heart attack” and “cardiac arrest” are commonly used interchangeably in the news and on TV shows, these conditions are actually different. It is a frequent misconception that heart attacks and cardiac arrest are the same thing. 

To understand what is cardiac arrest vs heart attack, let’s define what both of these heart problems are and unpack how they are different.

Cardiac Arrest Vs Heart Attack

The main difference between Sudden Cardiac Arrest vs heart attack is the underlying problem that occurs in the heart. 

  • Cardiac arrest is an electrical problem where a malfunction in the heart’s electrical system causes it to stop beating. Normally, the heart is controlled by regular electrical impulses that make it beat. When Sudden Cardiac Arrest happens, these electrical impulses become scrambled and the heart can no longer pump blood (containing oxygen that is necessary for life) around the body. 
  • By contrast, a heart attack is when the blood supply to the heart is cut off due to a blockage in an artery. This blockage causes damage to the heart and the muscle begins to die. 

Cardiac Arrest Definition

Medically-defined, cardiac arrest describes when the heart suddenly stops beating. Cardiac arrest can occur in an individual who has been diagnosed with a pre-existing heart condition or in people who are seemingly healthy.  

When someone suffers cardiac arrest, the electrical system in their heart stops functioning properly, causing the heart to stop beating. Without immediate treatment with CPR and an Automated External Defibrillator (AED), victims of cardiac arrest will die.  CPR manually pumps blood throughout the body until shocks from an AED actually restart the victim’s heart so that it beats normally again. 

Heart Attack Definition

A heart attack happens when the blood flow to the heart is cut off, which prevents the heart from receiving sufficient oxygen. Blood flow becomes restricted when one or more of the coronary arteries become blocked. A blockage in these arteries deprives the heart from receiving enough oxygen to function properly. 

When the heart does not receive oxygen, the blocked section of the heart starts to die. To save the muscle from dying, physicians must perform medical treatment to physically open the blockage or dissolve it. 


Cardiac arrest vs heart attack symptoms are what can distinguish these conditions, so it is important to know them. Recognizing the various signs can help someone receive the proper treatment they need efficiently. 

Cardiac Arrest

Victims of cardiac arrest will suddenly become unconscious and collapse. They are unresponsive and not rousable. They will also not be breathing normally. Sometimes, victims of cardiac arrest will make ragged breathing noises called agonal respirations that might sound like snoring or gasping.

This is not normal breathing and the victim needs treatment at once. Victims may also have strange muscle movements like clenching or shaking as if they are having a seizure. These are not normal movements and they do not mean the person is responsive. 

Likewise, there are also warning signs that cardiac arrest may occur:

  • Chest pain
  • Shortness of breath
  • Nausea
  • Weakness
  • Palpitations 

While some of these are similar to heart attack symptoms, sudden collapse, unresponsiveness, and no breathing are indicative of cardiac arrest. 

Heart Attack

Early detection of heart attack is very important for ensuring survival. Unlike cardiac arrest, which always happens suddenly, a heart attack can be sudden or may develop over time. The following signs and symptoms indicate that a heart attack may be happening: 

  • Chest pain
  • Spreading of chest pain to arms, jaw, neck, back, and abdomen
  • Coughing and wheezing
  • Anxiety
  • Weakness
  • Palpitations 
  • Shortness of breath
  • Dizziness
  • Sweating
  • Sick feelings

Chest pain is most commonly a feeling of tightness that centers on the chest and does not feel better with rest. While chest pain is often experienced by heart attack victims, not all patients will have these pains. The pain associated with a heart attack can manifest differently for men and women. In the event of any of these symptoms, it is essential to seek medical help immediately by calling 911. It is not recommended that people experiencing heart attack symptoms drive themselves to the hospital as their condition can deteriorate rapidly. 

Causes & Risk Factors

Along with differences in symptoms, cardiac arrest vs heart attack can have different causes or risk factors. Keep in mind that several things can cause either one of these medical emergencies. 

Cardiac Arrest

A cardiac arrest can be caused by a long list of conditions and risk factors, including:


Additionally, although cardiac arrest and heart attacks are different, the damage to the heart caused by a heart attack can cause an individual to go into cardiac arrest. In fact, most instances of cardiac arrest happen as a result of heart attacks.

Heart Attack

The most common cause of heart attacks is coronary heart disease. This disease happens when fatty deposits begin to build up in the coronary arteries. The following factors put individuals at a higher risk of coronary heart disease: 

  • Smoking 
  • Unhealthy diet 
  • Diabetes 
  • High blood pressure
  • Age 
  • Low exercise
  • Obesity 
  • Genetics 
  • Air pollution 

These factors and conditions can increase arterial plaque buildup, which can split off and block the coronary artery.

What to Do

Because cardiac arrest and heart attacks are both serious medical emergencies, it is critical that you know what to do should they occur.

Cardiac Arrest

The first thing you should always do if you suspect someone is experiencing cardiac arrest is to call 9-1-1 immediately. While on the phone with 911, it is essential that you jump into action by performing CPR. If you have never been trained in CPR, do NOT let that stop you from performing hands-only CPR where you push hard and fast on the center of the chest. Performing hands-only CPR immediately can double or triple a person’s chances of survival. While CPR manually pumps blood through the body, an Automated External Defibrillator or AED is needed to restart the heart. Instruct someone nearby to get an AED and use it. These devices come with step-by-step voice instructions that will tell you exactly what to do, even if you’ve never used one before. AEDs are designed for people without specialized medical training to use. 

Heart Attack

Like with cardiac arrest, immediately call 9-1-1 for emergency medical help if someone is having heart attack symptoms. From there, do your best to make the individual comfortable, supporting their head and shoulders and keeping their knees bent. 

Loosen their clothing around their neck, chest, and waist and continue to monitor their pulse, breathing, and consciousness. If they lose consciousness and you don’t feel a pulse, they may have entered cardiac arrest. 

Link Between Cardiac Arrest and Heart Attack

Cardiac arrest and heart attack are likely so commonly interchanged among the general public because the two are linked. In fact, the most common cause of cardiac arrest is a heart attack. 

Should a heart attack progress far enough before receiving treatment, it can impact heart muscle sufficiently to cause cardiac arrest. When this happens, the heart can stop beating. Once the heart stops beating, the individual has entered into cardiac arrest and they need immediate treatment with CPR and an AED. 


Cardiac arrest and heart attacks are emergency medical conditions that require fast action and quick thinking. In the event of these emergencies, it’s best to have the right equipment. An AED is the only tool that can restart the heart in the event of cardiac arrest.


Take a look at some common questions we see about heart attacks and cardiac arrest. 

Which is worse, a heart attack or cardiac arrest?

While both conditions are considered severe, cardiac arrest is more serious as it can lead to death within minutes. However, a heart attack can lead to cardiac arrest. In either case, individuals should receive immediate medical treatment and assistance from bystanders.

How do you know if you are having a heart attack or cardiac arrest?