Many people use the terms heart attack and cardiac arrest interchangeably, but these conditions aren’t the same.

A heart attack occurs when your heart doesn’t get enough blood flow. A cardiac arrest occurs when you experience a sudden collapse and loss of consciousness because your heart stops beating and can’t pump blood to supply oxygen to the rest of your organs. In many cases, a heart attack can raise your risk of developing cardiac arrest.123

Both heart attacks and cardiac arrest are life-threatening. While these conditions are related and can share similar symptoms, there are key differences.

Symptoms of a Heart Attack vs. Cardiac Arrest

Cardiac arrest and heart attacks both affect the heart, but each condition has different symptoms. A heart attack can often lead to cardiac arrest, so it’s important to recognize the symptoms of a heart attack and seek immediate medical care. Here’s a breakdown of how symptoms compare and contrast:1

Differences

Heart attacks and cardiac arrest are both serious conditions that affect your heart and overall cardiovascular health. However, they do differ in causes, treatments, and overall outcomes.

Different Conditions Causes Heart Attacks and Cardiac Arrest

Heart attacks happen when the heart does not get enough blood flow. The coronary arteries are the blood vessels that bring blood, oxygen, and nutrients to the heart muscle. The heart muscle is continuously working, normally beating 60-100 times per minute, so it needs a constant blood supply to work properly.6

The leading cause of heart attacks is atherosclerosis, a buildup of cholesterol plaque in the coronary arteries. These plaques can rupture, forming a blood clot that either partially or completely blocks blood flow to the heart.1

On the other hand, several conditions can lead to cardiac arrest. A heart attack is one of the primary reasons someone might experience cardiac arrest, but these conditions can also cause your heart to stop beating:

Arrhythmias (abnormal heart rhythms), such as ventricular fibrillation and ventricular tachycardia
Other heart conditions, like congenital heart defects and valvular heart disease
Hypoxia (low oxygen levels)
Hypothermia (low body temperature)
Low blood volume, such as with excess hemorrhaging (bleeding)
Excessively high or low potassium levels in the blood, with possibly severe magnesium and calcium imbalances
Hypoglycemia (low blood sugar)
Pulmonary embolism (blood clot in the lungs’ arteries)
Cardiac tamponade (fluid build-up around the heart)
Pneumothorax (collapsed lung)

A Quick Review

Heart attacks and cardiac arrest often get mistaken as the same thing, but they’re two separate conditions. A heart attack is more common and occurs when something blocks the blood supply to your heart. This can often lead to cardiac arrest, which occurs when your heart stops beating and causes you to lose all consciousness.

While both conditions require immediate care, the underlying causes, treatments, and outcomes for each condition differ—and understanding these differences is important so you know when to seek care for yourself or someone else.