Do you know the difference between a heart attack and cardiac arrest? Both are medical emergencies so it’s important to understand their causes, symptoms, and potential outcomes.

We asked Christopher B. Haas, DO, an interventional cardiologist and medical director of the UPMC Heart and Vascular Institute at UPMC Western Maryland, to explain the difference between these two serious conditions.

What Is A Heart Attack?

A heart attack, also called a myocardial infarction (MI), occurs when a heart artery (coronary artery) is unable to supply a part of the heart muscle with enough blood to keep it alive. This often is due to a sudden clot that forms in the artery, which stops the flow of blood in that artery, or to the slow build-up of cholesterol plaques around the heart artery that causes the artery to narrow significantly over months to years.

When blood flow is restricted or blocked, the heart muscle cells don’t get the oxygen they need and, after just a few minutes, they begin to die. This causes the heart muscle to malfunction and can lead to heart failure and/or death.

“Knowing the warning signs and symptoms of a heart attack is crucial,” says Dr. Haas. “Early treatment, especially within the first 90 minutes of the onset of a heart attack, can reduce the damage done to the heart and save your life.”

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Heart Attack Symptoms

Chest pain/pressure/discomfort lasting a few minutes or more is the main symptom of a heart attack. It is important to point out that although chest pain is an important symptom for women to recognize, they are less likely than men to feel it and often only have some of the other symptoms listed below. Men may have these, as well:

  • Shortness of breath.
  • Nausea.
  • Vomiting.
  • Sudden profuse sweating.
  • Dizziness.
  • Extreme weakness.
  • Anxiety.

A heart attack is a medical emergency that can be deadly without treatment. If you think you or someone else are having a heart attack, call 911 right away. Emergency medical services will provide the fastest, safest route to the hospital and are trained to treat you on the way.

What Is Cardiac Arrest?

“Cardiac arrest is when the heart stops beating, usually because of a problem with its electrical system,” explains Dr. Haas. “Typically, an electrical discharge from the heart’s electrical system causes the heart muscle to squeeze. If there is one electrical discharge per second, it usually results in a heart rate of 60 beats per minute and so forth.

“A common type of cardiac arrest is called ventricular fibrillation, or VF, which is from an electrical system gone haywire causing electrical chaos in the heart. There are so many electrical discharges in the heart conduction system per minute that the muscle cannot properly respond. The heart stops squeezing, and no blood circulates to the body or the brain,” says Dr. Haas.

“Another situation called ventricular tachycardia, or VT, also is due to a haywire electrical system, but it is less chaotic than VF. In VT, the heart beats so fast that the muscle becomes completely inefficient and little to no blood circulates. Last, the heart may beat so slowly, called bradycardia, that blood pressure cannot be maintained at a level high enough to circulate blood.”

Dr. Haas says what ties everything together is that a heart attack can lead to cardiac arrest if the blocked artery supplies a part of the electrical system. And the lack of blood there causes that part of the system to shut down or go haywire.

“Heart attacks also may cause such extensive damage to the muscle itself that it no longer is able to work properly, and the heart basically just stops beating,” he says. “Cardiac arrest may also be indirectly caused by a heart attack a person had years earlier since the heart attack leaves behind scar tissue in the affected part of the heart. This scar tissue can cause disturbances in how the normal electrical impulses of the heart travel around the organ, and lead to those deadly rhythms – especially VF and VT.”

Cardiac Arrest Symptoms

Cardiac arrest symptoms can include:

  • Sudden loss of consciousness.
  • Lack of pulse.

Cardiac arrest is a medical emergency that is deadly without immediate treatment. If you think someone is in cardiac arrest, call 911 immediately and start CPR. If an AED is available, use it as soon as possible.

If you think you are at risk of heart disease or heart attack, consult your primary care physician or visit the UPMC Heart and Vascular Institute website.

About Heart and Vascular Institute

The UPMC Heart and Vascular Institute has long been a leader in cardiovascular care, with a rich history in clinical research and innovation. As one of the first heart transplant centers in the country and as the developer of one of the first heart-assist devices, UPMC has contributed to advancing the field of cardiovascular medicine. We strive to provide the most advanced, cutting-edge care for our patients, treating both common and complex conditions. We also offer services that seek to improve the health of our communities, including heart screenings, free clinics, and heart health education. Find an expert near you.