Cardiac Arrest vs. Heart Attack: What’s the Difference?

People often use the terms “cardiac arrest” and “heart attack” interchangeably, as if they’re two ways of saying the same thing. But cardiac arrest and heart attack are two distinct conditions with different causes.

In the most basic of explanations:

• Cardiac arrest is an electrical issue in your heart. It occurs when quick, irregular impulses take over your heart’s rhythm to stop it from squeezing effectively (or at all).
• A heart attack is a blood-flow issue to your heart, usually because of a blockage in an artery. It disrupts the pumping function of your heart, which can reduce or stop blood flow to your body.

Let’s break it down more with cardiologist Andrew Higgins, MD.

How to tell the difference

Cardiac arrest and heart attack are both medical emergencies involving your heart. Both can be very, very bad — even life-threatening.

But there are often key differences in how they look in the moment.

During a cardiac arrest, when the heart stops beating and shuts down, expect someone to:

• Collapse suddenly
• Lose consciousness
• Stop breathing

“Cardiac arrest symptoms typically start without warning,” says Dr. Higgins. “You may or may not experience chest pain before you faint and become unconscious.”

During a heart attack, when blood flow slows or stops, symptoms tend to be less dramatic and can range from mild to severe. How a heart attack feels can vary widely based on your sex, age and underlying medical conditions, too.

Common symptoms include:

• Chest pain or pressure
• Shortness of breath
• Nausea or vomiting
• Sweating
• Dizziness or lightheadedness

“What may seem minor — like slight chest discomfort or shortness of breath — could be a warning sign of something much more serious,” says Dr. Higgins. “Never just dismiss what your body is trying to tell you.”

Can one cause the other?

Cardiac arrest itself does not directly cause a heart attack. But a heart attack can lead to cardiac arrest if your heart’s electrical system is disrupted due to the lack of blood flow.

“A heart attack can create chaos in the heart’s electrical system to trigger cardiac arrest,” explains Dr. Higgins. “That’s why it’s so important to recognize and respond to any symptoms so you can get treatment.”

What should you do for each?

If you’re in a situation dealing with either cardiac arrest or a heart attack, your first move is the same: Dial 911 or whatever number brings emergency workers to your location.

“Getting immediate medical treatment should be your No. 1 priority,” emphasizes Dr. Higgins.

After calling for help, here’s what else you can do in each situation.

In the case of cardiac arrest

Immediate action is critical. Cardiac arrest can be fatal if CPR (cardiopulmonary resuscitation) isn’t started within eight minutes to help your heart begin pumping again.

If an automated external defibrillator (AED) is available, use it to jumpstart the heart.

“Timely defibrillation could mean the difference between walking out of the hospital or dying,” stresses Dr. Higgins.

Unless a heart rhythm is restored as soon as possible, your brain starts to die from a lack of oxygen and blood flow. The results can be fatal.

“If you’re reading this and are unsure how to perform CPR or use an AED, organizations like the American Heart Association, local schools, libraries and fire departments offer courses,” shares Dr. Higgins. “You could save a life by preparing yourself now.”

In case of a heart attack

A heart attack may not be as intense a situation as a cardiac arrest, but that doesn’t mean you can relax. Action is needed, as a lack of blood flow to your heart can permanently damage or kill muscle within it.

So, while you wait for emergency crews to begin treatment, you can:

• Take medication. If you have a prescription for a medication like nitroglycerin, take it while you wait for an ambulance to arrive. Another option? Slowly chewing 325 milligrams of aspirin may help reduce damage and prevent blood clots from forming.
• Get comfortable. Sitting in a semi-reclined position with your chest elevated can help reduce strain on your heart and lungs. It’s best not to lie flat, as that may make breathing more difficult.
• Stay calm. Panicking can cause your heart rate and blood pressure to rise, which can put additional strain on your heart. So, difficult as it may be, try to remain calm and relaxed.

Final thoughts

While cardiac arrest and heart attack are different, both are emergencies that deserve immediate attention.

“Whether it’s sudden collapse from cardiac arrest or subtle chest discomfort from a heart attack, your best chance for a positive outcome starts with a fast response,” reiterates Dr. Higgins. “Every second counts.”