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

April 04, 2022

People often confuse heart attack and cardiac arrest, or think they are the same thing.

They aren’t.

In short, heart attack is a plumbing issue. Sudden cardiac arrest is an electrical issue.

A heart attack can sometimes trigger sudden cardiac arrest, but most do not, says University Hospitals interventional cardiologist Yulanka Castro-Dominguez, MD.

Heart attack happens when a blockage in a coronary artery stops blood flow to a portion of the heart muscle. Cardiac arrest usually happens because of an electrical malfunction, often a rhythm disorder called ventricular fibrillation. Faulty electrical signals cause the lower pumping chambers of the heart – the ventricles – to quiver. The heart then can’t pump blood to vital organs.

Symptoms

Usually, symptoms of heart attack such as chest discomfort persist for a while (symptoms are variable). Emergency treatment involves reopening blocked arteries before lack of blood flow damages the heart muscle.

About 800,000 people in the United States suffer heart attacks every year.

Cardiac arrest happens quickly. A person loses consciousness and stops breathing. Automatic external defibrillators found in many public buildings can jolt the heart back into a beating rhythm.

Absent a defibrillator, immediate chest compressions can double or triple chance of survival, according to American Heart Association. Without treatment, a person will die within minutes.

“For this reason, obtaining training in preforming cardiopulmonary resuscitation (CPR) is so important and can potentially save lives,” Dr. Castro-Dominguez says.

More than 350,000 people a year suffer cardiac arrest outside of hospitals in the United States. About 90 percent are fatal.

Causes

Coronary artery disease – narrowing of the arteries due to buildup of substances called plaques – causes most heart attacks. When plaque ruptures, a clot forms and partially or completely blocks an artery.

Sudden cardiac arrest can be caused by coronary artery disease and other heart conditions.

A severe heart attack causing lack of blood flow to a significant portion of the heart muscle can lead to a cardiac arrest, Dr. Castro-Dominguez says.

Certain heart medications, congenital heart defects, electrical abnormalities and using certain recreational drugs also increase the risk.

Who’s at risk?

Risk factors for coronary artery disease, heart attack and sudden cardiac arrest are similar: high blood pressure, high cholesterol, smoking, diabetes, obesity and sedentary lifestyle.

You can reduce your risk with lifestyle changes and by getting regular checkups and screenings for heart disease.

“Knowing your numbers is key to understanding your personal risk of developing heart disease,” Dr. Castro-Dominguez says. “This means knowing your blood pressure, cholesterol levels, fasting blood sugar and body mass index. We recommend visiting your primary doctor and asking about evaluating your risk of having heart disease. “