This One Symptom Could Warn of Cardiac Arrest in 24 Hours

Nine out of 10 people who experience sudden cardiac arrest outside of a hospital setting die—often within minutes.

One reason for these fatal outcomes is the commonly held belief that cardiac arrest occurs without warning. But research suggests telltale symptoms may appear before cardiac arrest, and recognizing them can give folks more than a fighting chance.

For men, the main symptom before cardiac arrest is the unexpected onset of chest pain. For women, however, it’s the unexpected onset of shortness of breath. These signs may occur 24 hours before sudden cardiac arrest. according to a study published in the Lancet Digital Health in 2023.

“Fully 50% of men and women report these warning symptoms before cardiac arrest,” study author Sumeet Chugh, MD, the medical director of the Heart Rhythm Center in the Department of Cardiology, tells The Healthy by Reader’s Digest.

What is cardiac arrest?

Cardiac arrest occurs when the heart unexpectedly stops pumping blood. Cardiac arrests are caused by certain types of arrhythmias or heart rhythm abnormalities that prevent the heart from pumping blood.

The first obvious sign of cardiac arrest is often a loss of consciousness. From there, there’s is a 10% chance of death for every minute that goes by, and within 10 minutes, most people will have passed.

Recognizing early warning signs, however, could dramatically improve a person’s odds of survival.

Look for the warning signs

Dr. Chough and his colleagues conducted studies in Ventura County, California, and Portland, Oregon. They looked for individual symptoms and sets of symptoms before sudden cardiac arrest and compared these findings to the symptoms of people who also sought emergency medical care but did not have a cardiac arrest.

Indeed, half of the 823 people who had a sudden cardiac arrest witnessed by a bystander or emergency medicine professional in California experienced at least one telltale symptom 24 hours previously. The Oregon-based study showed similar results.

Most people just blow off these symptoms, but calling 911 can be a lifesaver, Dr. Chough says: “Only 20% of people experiencing these symptoms before cardiac arrest call 911, but they had a six-fold higher survival than the 80% who don’t.”

Quick action is vital

Warning symptoms matter, but not all cases of chest pain or shortness of breath are harbingers of cardiac arrest, Dr. Chough notes. “We have to combine other features with warning symptoms to help people understand if they are likely experiencing a cardiac arrest and need help right away,” he says. These may include high blood pressure, diabetes, or other underlying diseases, Dr. Chough says.

If you experience an unexpected onset of chest pain or shortness of breath, seek medical care immediately, especially if you have known heart disease.

Bystander CPR saves lives, he adds. “We need the public to learn CPR and how to locate and use an automated external defibrillator (AED).” Such quick action is why Lebron James’ son Bronny and NFL player Damar Hamlin, for example, survived cardiac arrests.

Knowing the early warnings symptoms of cardiac arrest may save lives, says Deepak L. Bhatt, MD, MPH, the Director of Mount Sinai Heart in New York City. “There may be an incorrect belief out there that sudden cardiac arrests never have any symptoms, but a proportion of them do have warning symptoms, as seen in this study,” he tells The Healthy. “And in those cases, it could potentially have been lifesaving to call 911 as soon as those symptoms, such as chest pain, started instead of waiting.”

• Cardiac Arrest vs. Heart Attack: A Cardiologist Explains the Differences
• 6 Warning Signs You May Be at Risk for Cardiac Arrest
• The Widowmaker Heart Attack: Cardiologists Explain the Meaning
• Can You Die from a Broken Heart? A Cardiologist Answers