WEDNESDAY, Aug. 6, 2025 (HealthDay News) — Cardiac arrest is defined as a sudden stop in heart function. Essentially, the pumping function of the heart is compromised, oftentimes due to a dangerous malfunction of the heart’s electrical system. 

Cardiac arrest can be fatal if not immediately treated with cardiopulmonary resuscitation (CPR). More than 436,000 people die each year in the United States as a result of cardiac arrest. Knowing the signs of cardiac arrest and how to respond quickly can save lives. 

Cardiac arrest often comes on abruptly and without warning. It can happen in individuals who have been diagnosed with a previous heart condition, and also in those who have had no prior heart problems. It usually is the result of an electrical failure in the heart’s rhythm conduction system (referred to as an arrhythmia). 

This compromises the heart’s ability to pump effectively and limits its ability to circulate blood to other organs, including the brain and lungs. The heartbeat essentially stops, and individuals who experience a cardiac arrest will lose their pulse, lose consciousness and stop breathing. 

What is cardiac arrest?

The terms cardiac arrest and heart attack are often confused. A heart attack is different from a cardiac arrest, and refers to a blood flow problem in an artery of the heart due to a blockage. Patients having a heart attack (also called myocardial infarction) often experience chest pain or difficulty breathing.      

The heart can usually continue to beat despite a heart attack, but it can sustain significant damage if left untreated. Cardiac arrest can sometimes occur if a heart attack progresses and is not treated. 

Causes of cardiac arrest

Heart attack is not the only cause of cardiac arrest. It can also happen in patients with an underlying cardiomyopathy, which causes chronic heart muscle damage. These patients are prone to heart failure. 

Cardiomyopathies can be the result of congenital heart issues or genetic conditions such as hypertrophic cardiomyopathy (HCM), which is a condition where the heart muscle is thickened.

Cardiomyopathies can also develop in patients with longstanding, uncontrolled high blood pressure (hypertension), which can eventually lead to both heart muscle thickening and heart pumping failure.

Patients with a history of arrhythmias such as ventricular tachycardia (VT) are also at risk for cardiac arrest. These are just a few examples of some of the conditions that can lead to chronic heart damage.

Symptoms of cardiac arrest

It is important to identify the signs of a cardiac arrest. If a hospitalized patient experiences a cardiac arrest, this is usually immediately identified by a heart rhythm monitor or a physical exam that demonstrates the loss of a pulse. Unfortunately, many cardiac arrests occur outside of a hospital, and that is why knowing the signs and symptoms of a cardiac arrest is crucial. 

Some individuals will experience symptoms such as sweating, chest discomfort, difficulty breathing or heart racing before having a cardiac arrest. However, some individuals will not experience any notable symptoms and may collapse suddenly and without warning. 

Immediate treatment for cardiac arrest

The good news is that anyone, regardless of their level of medical experience, has the opportunity to save someone’s life by initiating life-saving CPR. Taking a CPR course can help you become properly trained and certified, better preparing you for any scenario. 

When someone loses consciousness, first check for a pulse by placing fingers on the neck (carotid artery) or wrist (radial artery). Immediately shout for help and call 911 to request emergency services. 

While waiting for emergency services to arrive, it is imperative to initiate CPR with chest compressions. You should push hard and fast in the center of the chest to administer CPR.

It is recommended that chest compressions be performed at a rate of about 100 to 120 compressions per minute. The American Heart Association suggests doing compressions to the beat of the song “Stayin’ Alive.”

If possible, have someone locate an automated external defibrillator (AED). Turn it on and follow the instructions as soon as it arrives. You should continue CPR and follow the prompts from the AED until emergency services arrive. 

It can be frightening to think about having to act fast in an emergency. People can be afraid and it can be challenging to jump into action when an emergency occurs. It can be especially overwhelming if the individual is a friend or loved one.

However, by bravely initiating CPR, you have the ability to save a life. Bystander CPR has consistently been shown to improve an individual’s odds of survival from cardiac arrest. The earlier that CPR is started, the better the chances of survival. Chest compressions will temporarily replace the pumping function of the heart, helping to provide blood circulation to the organs. The AED has the ability to shock the heart externally, and help to restore heart rhythm. 

Anyone can learn to perform effective, life-saving CPR by taking a course and becoming certified. You can check out cpr.heart.org to locate a training course near you.  

Survival rate and prognosis

With early treatment and medical care, individuals who have suffered a cardiac arrest can recover. With early CPR, they have a better chance of improved blood flow to the brain, improving their chances of recovering without significant brain damage. 

Prevention of cardiac arrest

In addition to becoming familiar with CPR training, it is also important to know your own cardiac risk factors. Routine health screenings will make you aware of your own risk factors, including your blood pressure, cholesterol levels and diabetes risk.

It is imperative to quit smoking. If you have a family history of heart problems, have high blood pressure, high cholesterol, diabetes or are a smoker, you may be at an increased risk of heart disease. 

When to seek medical help

Though cardiac arrest can occur suddenly and without warning, sometimes there are early warning signs, and it is important to stay proactive about heart health screening. If you experience any symptoms that may be suggestive of an underlying heart condition, it is vital to seek medical attention.

Some of these warning signs and symptoms include chest discomfort (pain, tightness or pressure), shortness of breath, difficulty breathing at night, palpitations (heart racing, fluttering or skipping beats), swelling in the legs, increased sweating, or a decrease in your energy levels or tolerance of exercise.

It is important to seek out a trusted medical provider who can evaluate these symptoms and potentially order further tests to identify whether you may be at risk for heart complications in the future. They can begin treatment to lower your risk for complications such as a heart attack and cardiac arrest. 

Though cardiac arrest can be a dangerous and fatal condition, with the appropriate health screening, risk factor assessment, and education, it can potentially be avoided. In cases where cardiac arrest occurs, the proper CPR training and preparation have the ability to restore blood flow and save a life. Wehave the tools to fight back against heart disease and live longer and healthier lives. Additionally, with the right education and proper CPR training, we also have the ability to serve as heroes for our family, friends and communities.

About the expert

Alana Lewis, MD, is a board-certified cardiologist at Northwestern Medicine Bluhm Cardiovascular Institute. Her practice focuses on coronary artery disease, echocardiography, general cardiology, preventive care, and women’s cardiovascular health. Dr. Lewis is certified by the American Board of Internal Medicine in both internal medicine and cardiovascular disease.