Both are emergencies; one is more fatal than the other

By Rachael Zimlich, BSN, RN 

Updated on October 25, 2023

 Medically reviewed by Richard N. Fogoros, MD

Cardiac arrest and heart attack are medical emergencies, but cardiac arrest is more fatal. A heart attack is when blood flow to the heart is disrupted, whereas cardiac arrest is when the heart suddenly stops beating.¹² Immediate intervention is critical for both events.

This article discusses the differences and symptoms of cardiac arrest vs. heart attack.

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Cardiac Arrest vs. Heart Attack: Major Differences

A heart attack is a medical emergency that occurs when the blood flow to the heart is disrupted or the heart muscle gets too weak to pump blood efficiently. Heart attacks can lead to cardiac arrest, but not always.

 Myocardial Infarction (Heart Attack)

Cardiac arrest happens when the heart suddenly stops beating altogether. Heart attack (also called myocardial infarction) is one cause of cardiac arrest, but there are others, too, including:³²

• Cardiomyopathy: Stiffened and enlarged areas of the heart muscle that cause abnormal contractions

• Coronary artery disease: Narrowing or blockages in the blood vessels that bring blood to the heart

• Valvular heart disease: Problems with the valves that separate the chambers of the heart and direct blood flow

• Arrhythmias: Abnormal beats and electrical signals that change the pattern of the heartbeat, such as long QT syndrome

 Restrictive Cardiomyopathy

Emergency Symptoms

A heart attack can appear with several symptoms that signal a problem. Heart attack symptoms include:⁴⁵

• Chest pain

• Dizziness

• Pain in the jaw, shoulder, or back

• Pain or discomfort in one or both arms

• Shortness of breath

• Sweating

Cardiac arrest, on the other hand, is typically sudden and unexpected. There may be warning signs like heart attack symptoms, but a person experiencing cardiac arrest may also:⁶²

• Gasp for air or stop breathing

• Have no pulse

• Lose consciousness

Quick Check: Heart Attack or Cardiac Arrest?

Symptoms of a heart attack, like chest pain and shortness of breath, can come before a heart attack or cardiac arrest. People who suffer from cardiac arrest suddenly lose a pulse, stop breathing, and become unconscious. If you see someone collapse, assume they are in cardiac arrest and call 911.

 Warning Signs of a Heart Attack in Women

Causes and Risk Factors

Heart problems like coronary artery disease or cardiomyopathy are leading contributors to heart attack and cardiac arrest. Still, the following can play a role in heart disease, heart attack, and cardiac arrest:⁷⁸

• Cigarette smoking

• Drug use

• Heavy alcohol consumption

• High blood pressure

• High cholesterol

While heart-related factors often cause heart attacks, cardiac arrest has a broader range of causes, including:⁹

• Abnormal electrical activity in the heart (arrhythmias)

• A change in the body's pH levels (acidosis)

• A lack of oxygen in the blood (hypoxia)

• Blood clots (thrombosis)

• Changes in the pressure in the lungs (tension pneumothorax)

• Fluid collections around the heart (cardiac tamponade)

• Severe dehydration or blood loss (hypovolemia)

• Too much or too little potassium in the blood (hyperkalemia/hypokalemia)

Cardiac Arrest vs. Heart Attack: Immediate Actions to Take

Heart attacks and cardiac arrest require emergency treatment. How they are treated will depend on the underlying cause, but chances of survival with cardiac arrest depend more on immediate actions.

Heart Attack Care

The heart requires a constant flow of oxygen-rich blood, and any disruption in this blood flow can cause permanent loss of cardiac muscle. A heart attack occurs when blood flow to the heart is interrupted. Heart attack treatment depends on whether you have a partial or complete blockage of blood supply to the heart and the extent of damage to the heart.⁷¹

Treatment for heart attacks can range from medications, such as anticoagulants (blood thinners), to surgery, often requiring a combination of both.¹⁰

Cardiac Arrest Care

Cardiac arrest requires immediate intervention to support heart function. The brain and other tissues become quickly damaged without blood flow, and high-quality cardiopulmonary resuscitation (CPR) can keep blood flowing.

CPR

CPR should be started as soon as possible after observing a cardiac arrest. Even CPR from an untrained person can help. According to the American Heart Association, nearly 75% of cardiac arrests happen outside the medical setting, and only about 40% of those people get the immediate care, such as CPR, needed for survival.

When basic life support (BLS) is administered effectively and immediately, it can double or even triple survival rates after cardiac arrest.¹¹

Sometimes, CPR may be enough to resolve cardiac arrest, though most people with cardiac arrest require medications like epinephrine or amiodarone and treatments like defibrillation or mechanical ventilation.

Automated external defibrillators (AEDs) are available in some public areas. They can help guide untrained individuals through the steps of BLS and ensure rapid use of defibrillation if needed—ideally within five minutes of the cardiac event.¹¹¹²

Even after recovery from cardiac arrest—also known as return of spontaneous circulation (ROSC)—a person will require additional monitoring and treatment to identify and treat any ongoing problems.

How Heart Attack Can Become Cardiac Arrest 

Heart attacks usually only lead to cardiac arrest when the damage is severe, or blood flow to the heart is completely blocked. By interrupting blood flow to the heart muscle, a heart attack can trigger a dangerous heart arrhythmia called ventricular fibrillation, which immediately stops the heart from pumping.

Cardiac Arrest vs. Heart Attack vs. Heart Failure 

You may hear "cardiac arrest," "heart attack," and "heart failure" being used interchangeably, but they are different events, as follows:

• Cardiac arrest is a medical emergency requiring immediate intervention and treatment. Even with excellent care, many cases of cardiac arrest are fatal or result in chronic health problems.²

• Heart attacks can also be fatal or cause ongoing problems, depending on how quickly and effectively the blockage in blood flow to the heart is cleared. Treatment usually involves medications and procedures like cardiac catheterization or bypass.¹

• Heart failure is a chronic condition resulting from weakened heart muscle or other cardiac problems that limit the heart's ability to pump blood throughout the body. Cardiac arrest and heart attacks can lead to heart failure.¹

Recovery and Prognosis 

More than 350,000 cardiac arrests happen outside of medical facilities each year, and only about 10% of these people survive.¹³ Survival depends on immediate treatment and the factors contributing to cardiac arrest. Even if a heartbeat is restored, cardiac arrest can cause additional complications that cause ongoing problems or even death.

Immediate intervention from a medical provider and CPR from a bystander can help improve the chances of survival. The long-term prognosis depends on the cause of cardiac arrest, the success of post-arrest care, and any additional complications.¹¹¹³

Heart attacks that don't progress to the point of cardiac arrest have a better outlook. As many as 90% of people now survive heart attacks—a vast improvement from 50 years ago.¹⁴¹⁵

Advanced cardiac care—including cardiac catheterization, stents, and medication management—has helped improve survival rates. However, it also means more people live with cardiac or heart failure problems.

Scarring and loss of heart muscle after a heart attack can cause chronic problems, and it's estimated that more than 1 million people are hospitalized due to heart failure yearly.¹⁵

Prevention Measures

Caring for your heart can help you avoid heart attack and cardiac arrest. Prevention measures include:

• Eating a balanced, healthy diet rich in fresh fruits, vegetables, and fiber

• Maintaining a healthy cholesterol level

• Avoiding heavy drinking, smoking, and drug use

• Getting regular exercise

If you are diagnosed with cardiac problems, high blood pressure, high cholesterol, and other chronic health issues, staying compliant with your prescribed medication regimen, making appropriate lifestyle changes, and seeing a healthcare provider regularly can help keep you on track to avoid severe complications like heart attack and cardiac arrest.

Summary

Cardiac arrest and heart attacks require immediate medical treatment to avoid severe and ongoing health problems. Heart attacks result from disrupted blood flow to the heart, whereas cardiac arrest has varying causes that ultimately stop the heart from beating. If you witness someone experiencing cardiac arrest, intervening with CPR or BLS may help save their life.