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From Symptoms to CPR: What to Know about Sudden Cardiac Arrest

From Symptoms to CPR: What to Know about Sudden Cardiac Arrest

October 27, 2023 Posted in: Heart & Vascular Care  4 minute read time


Sudden cardiac arrest (SCA) is the medical term for the sudden loss of heart function. It’s different from a heart attack and often occurs without warning. However, experts now say that sudden cardiac arrest may not be so sudden or subtle after all. In a study published in The Lancet, investigators found that half of all people who have sudden cardiac arrest will feel symptoms the day before. What’s more, the study also suggests that the signs are different in men than in women–with men feeling chest pain and women experiencing shortness of breath.

News of these possible warning signs may give people a better fighting chance. Knowing what to do and acting promptly can make a lifesaving difference. Here’s what you need to know and do if you or someone you know is in sudden cardiac arrest.

What is sudden cardiac arrest?

Sudden cardiac arrest happens when the heart suddenly stops beating, and no blood is pumped to the brain and other vital organs. If left untreated, the chances of survival may be slim. Someone is likely having a cardiac arrest if they:

  • Collapse or pass out suddenly

  • Are not breathing, or are gasping for air

  • Do not respond to shaking or shouting

  • Have no pulse

If you or someone you know is in sudden cardiac arrest, call 911 immediately, start CPR by hand and use an automated external defibrillator (AED) if one is available.

Is sudden cardiac arrest the same as a heart attack?

Sudden cardiac arrest is different from a heart attack. In fact, sometimes it can happen after or while recovering from a heart attack. A heart attack is a “circulation” problem, and sudden cardiac arrest is an “electrical” problem. During a heart attack, the blood supply to the heart is blocked, but the heart keeps beating. In sudden cardiac arrest cases, the heart suddenly stops beating, and there’s no blood supply to the rest of the body. Unlike people who experience a heart attack, those with sudden cardiac arrest won’t have a pulse.

What causes sudden cardiac arrest?

Your heart has an electrical system that controls the rate and rhythm of your heartbeat. Sudden cardiac arrest can happen when the heart's electrical system malfunctions and causes irregular heartbeats, also called arrhythmias. There are different types of arrhythmias. Some may cause the heart to beat too fast, too slow or irregularly. Others can cause the heart to stop pumping blood to the body, potentially leading to cardiac arrest. Certain diseases and conditions can cause electrical problems that lead to sudden cardiac arrest. They include ventricular fibrillation, coronary artery disease (CAD), cardiomyopathy, valvular heart disease, arrhythmias, some inherited disorders and some types of physical stress.

How common is sudden cardiac arrest?

Sudden cardiac arrest can happen at any age. It’s rare in young people, but it can happen in young athletes who don’t know they have a heart problem. Warning signs to watch out for during exercise include dizziness, chest pain, seizures, fainting and shortness of breath. 

How can sudden cardiac arrest be prevented?

Your risk for sudden cardiac arrest is higher if you’re an older man or identify as Black or African American – especially if you already have diabetes, high blood pressure, heart failure or chronic kidney disease. Having coronary artery disease, heart attack or heart failure also makes you more likely to have sudden cardiac arrest.

You may lower your risk of sudden cardiac arrest by following a heart-healthy diet, exercising regularly, quitting smoking, staying on top of your blood pressure and cholesterol and limiting alcohol. If you have heart disease, treating your condition can also lower your risk. If you have had a sudden cardiac arrest episode before, getting an implantable cardioverter defibrillator (ICD) can lower your chance of having another one.

The takeaway.

Cardiac arrest occurs when the heart suddenly and unexpectedly stops beating. Quick action can result in double or triple survival rates. Shortness of breath and chest pain can be telltale signs, but these symptoms can occur for other reasons. If you see that someone is unconscious or gasping for air, they may be in cardiac arrest. Call 911 immediately, start CPR and use a defibrillator, if available. Talk to your doctor if you have an existing heart condition or other chronic conditions that may elevate your risk for sudden cardiac arrest.


Warning symptoms associated with imminent sudden cardiac arrest: a population-based case-control study with external validation - The Lancet Digital Health

Cardiac Arrest - Treatment | NHLBI, NIH

Sudden Cardiac Arrest | Sudden Cardiac Death | MedlinePlus

Cardiac Arrest |

Sudden Cardiac Death in Athletes - PMC (

Heart Attack and Sudden Cardiac Arrest Differences | American Heart Association

Cardiac Arrest - Symptoms | NHLBI, NIH

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