The difference between a heart attack and cardiac arrest

insider@insider.com (Kelly Burch)
A heart attack often results in severe chest pain — cardiac arrest leads to an immediate loss of consciousness.

Science Photo Library/Getty Images

  • A heart attack is not as dangerous as cardiac arrest, though both heart conditions are serious. 
  • A heart attack occurs when blood flowing to the heart is blocked, while cardiac arrest occurs when the heart suddenly stops pumping blood. 
  • Cardiac arrest is fatal 89% of the time — a heart attack is only fatal if it leads to cardiac arrest, which occurs in 14% of cases. 
  • This article was reviewed by Purvi Parwani, MD, cardiologist and director of the Women's Heart Health Clinic at Loma Linda University International Heart Institute
  • Visit Insider's homepage for more stories.

While heart attacks and cardiac arrest are both dangerous heart conditions, they have some key differences. 

Understanding the different symptoms, causes, and risk factors can help you get the appropriate help and treatment in each case. Here's what you need to know. 

Cardiac arrest is more dangerous than a heart attack 

Cardiac arrest is when the heart stops pumping blood through the body because it's not beating effectively. Someone experiencing cardiac arrest will lose consciousness within a matter of seconds, and it can be deadly if it's not reversed within minutes. In fact, cardiac arrest is fatal more than 89% of the time.

During the time that blood isn't flowing through the body, other organs are deprived of oxygen. This can be particularly dangerous in the brain, and neurological injuries are common for those that survive cardiac arrest. 

A heart attack is a blockage in an artery that prevents blood from flowing to the heart, leading to damage in the muscle. Heart attack symptoms include chest pain and tightness, which can radiate through the neck, jaw, and left shoulder, and may be accompanied by nausea, lightheadedness, shortness of breath, and sweating — but generally doesn't cause the person to pass out like cardiac arrest. In 20% of cases, heart attacks are "silent" and have no noticeable symptoms at all. 

Major heart attacks, where an artery is completely blocked, are very serious and require immediate treatment. About 14% of heart attacks are fatal. Severe heart attacks, even when treated, can lead to cardiac arrest, in rare cases, or heart failure, a condition where the heart fails to provide enough blood to the body over time (though it doesn't stop beating entirely, like cardiac arrest). 

There are different risk factors and symptoms 

According to Emily Zeitler, MD, a cardiologist at Dartmouth-Hitchcock Medical Center, cardiac arrest happens when the electric pulses that control the beating of the heart malfunction. This can cause the heart to suddenly stop beating or to beat so fast that it's not able to pump blood, which can happen with conditions like ventricular fibrillation

Most heart attacks do not lead to cardiac arrest, Zeitler says. However, when the damage from lack of blood flow to the heart causes the heart to stop beating, cardiac arrest can occur — these are the 14% of heart attacks that are fatal. 

A previous heart attack or coronary heart disease increases your risk of experiencing cardiac arrest in the future. Seventy-five percent of deaths from cardiac arrest are linked with a previous heart attack, and 80% of deaths from cardiac arrest are linked to coronary heart disease. 

The risk for experiencing cardiac arrest following a heart attack is highest within the first six months. Heart failure and other cardiovascular health complications can also increase your risk. 

Treating cardiac arrest and heart attacks

In cases of cardiac arrest, the heart must be restarted within minutes, using CPR or a defibrillator. The chance of surviving cardiac arrest decreases the longer the episode lasts, and drops to just 10% after 8 minutes and 24 seconds without a pulse. People who go into cardiac arrest around others who are able to call for help are nearly three times as likely to survive the incident.

Once the cardiac arrest victim is brought back to life, the treatment focuses on identifying and mitigating the cause of cardiac arrest. High-risk patients might be fitted with an implantable cardioverter defibrillator (ICD), a device that shocks the heart into a normal rhythm when an irregular rhythm is detected. 

The treatment for heart attacks depends on the position and size of the blockage. Sometimes the blockage can be cleared with thrombolytic therapy, the use of medications to break up clots. 

Sometimes patients who have a heart attack may be given a stent. This medical device is placed using a catheter and props the artery open, ensuring proper blood flow to the heart. 

After the immediate blockage is treated, many heart attack patients are prescribed medication to reduce cholesterol or prevent clots. Aspirin can reduce the likelihood of heart-attacks in high-risk patients and people with heart disease. Doctors will also recommend lifestyle changes, like reducing fatty foods and exercising regularly.

Related stories about heart health:

Read the original article on Insider