Heart attack vs. cardiac arrest

Heart attacks and cardiac arrest are two different things. In the last 15 years of taking care of hospitalized patients with heart attacks and cardiac arrest, I noticed many people didn’t properly understand the difference between the two. In this article, I will compare and contrast heart attacks and cardiac arrest so you can clearly tell the difference between the two. I am writing this article based on my personal experience as well as a review of relevant medical journals.

A heart attack is an important cause of cardiac arrest, but not all heart attacks lead to cardiac arrest. There are many causes of cardiac arrest other than a heart attack.

Here is a table contrasting heart attacks to cardiac arrest.

Heart attackCardiac arrest
CauseBlocked artery supplying blood to the heart, leading to damaged heart musclesHeart stops pumping blood
SymptomsMost common symptom is heavy pressure-like pain in the middle of the chest radiating to the left arm or shoulder. May have many other symptoms, read the article for details.Sudden collapse, no response when calling or shaking, no breathing, no pulse
DiagnosisNeeds evaluation by ER doctor for proper diagnosisDiagnosis of cardiac arrest is evident when you see the symptoms. Diagnosis of what caused the cardiac arrest needs full evaluation by ER doctor.
TreatmentTreatment is effective when started urgently after proper diagnosis in the ER.Treatment is only effective if CPR is started right away. AED may help. Waiting for paramedics may close the window of opportunity for treatment. Learn CPR and AED use if you want to save lives by reviving cardiac arrest.
OutcomeMay have a good outcome if proper diagnosis and treatment is performed within an acceptable timeframe.Outcome depends on the cause of the cardiac arrest. Very good outcome in some reversible causes of cardiac arrest if revived in time.
Comparing heart attacks and cardiac arrests

Read the rest of the article for details.

What’s the difference between heart attacks and cardiac arrest?

A diagram showing how a heart attack causes damaged heart muscles while cardiac arrest leads to a collapse of blood circulation.
A diagram showing the differences between a heart attack and cardiac arrest

A heart attack is caused by a sudden blockage of blood flow to the heart muscles. Heart attacks may damage your heart muscles if not treated urgently.

Cardiac arrest, on the other hand, happens when the heart suddenly stops pumping blood. Unlike heart attacks, cardiac arrest results in death if CPR is not started right away. A major heart attack that damages heart muscles so badly that they stop pumping blood is when a heart attack and cardiac arrest happen at the same time. Immediate cardiac arrest from a heart attack is rare, but patients who have suffered heart attacks are at a high risk of having cardiac arrest later.

How often does a heart attack lead to cardiac arrest?

Based on several studies, it is estimated that 2% to 4% of patients are at risk of having a cardiac arrest within a year of the initial heart attack. The risk of having a cardiac arrest after a heart attack is the highest in the first 30 days and goes significantly down after 2 years.

Here is a table that gives you the risk of cardiac arrest after a heart attack (Based on the data provided by Massachusetts Medical Society in 2005):

Time since heart attackRisk of cardiac arrest
First 30 days1.4% per month
1 month to 6 months0.5% per month
6 months to 12 months0.27% per month
12 months to 24 months0.18% per month
Greater than 24 months0.14% per month
Risk of cardiac arrest after a heart attack

Symptoms of heart attacks vs cardiac arrests

In most cases, symptoms of cardiac arrest are quite different from symptoms of heart attacks. You can easily recognize cardiac arrest when you see it. The symptoms of a heart attack are not always as easy to recognize.

Here are the symptoms of cardiac arrest:

  1. Sudden collapse
  2. Person not responding when called or shaken after the collapse
  3. Person not breathing after the collapse
  4. No pulse or heart rate detected after the collapse

If you see those 4 symptoms, you need to start CPR right away if you know how to do it. Otherwise, call 911 and try to find someone near you who can perform CPR. Basic CPR classes are widely available throughout the United States, and it is a good idea to get yourself certified for CPR. You don’t need any special training for it. No matter what you do for a living, you can get certified in basic CPR after short training that only takes a day or two. Many high schools across the nation have CPR certification as a part of a class. You could be at the right place at the right time and save someone’s life by getting CPR certified.

If you are in a public place like an airport or train station where you have an access to an AED, it will greatly improve the odds of successful revival. CPR training usually gives you the basic knowledge to operate an AED. If you are not comfortable using an AED, you can continue CPR until the paramedics arrive. CPR alone can buy the person some time, greatly increasing the chances of survival.

Symptoms of a heart attack vary significantly from person to person. Sometimes even doctors have a hard time knowing whether the particular symptoms of a person are related to a heart attack or not. A diagnosis of a heart attack requires an EKG and blood tests. It is important to have a high level of suspicion and seek help whenever you think you or someone you love might be having a heart attack. Call 911 immediately if you suspect a heart attack. The actual symptom you see could be slightly different from any of those listed below, but the list should give you a general idea of what symptoms of a heart attack look like.

Here are the possible symptoms of a heart attack, in order from most to less common:

  1. Heavy pressure-like pain in the middle of the chest, radiating to the left arm or shoulder
  2. Dull chest pain going into the left shoulder
  3. Sudden onset chest tightness and heaviness without actual pain
  4. Left arm or left jaw pain that feels like a crushing pressure, tightness, or heaviness
  5. Sudden onset heavy sweating
  6. Heart suddenly racing in the chest with a feeling of tightness
  7. Feeling very uncomfortable in the chest without actual pain or pressure
  8. Upper back pain that feels dull and pressure-like
  9. Shortness of breath with chest tightness
  10. Sudden nausea
  11. Feeling like you suddenly lost all of your energy
  12. Feeling like you have indigestion
  13. Feeling like you have heartburn all of a sudden
  14. Feeling like a rope is tightening around your chest area
  15. Sudden stomach discomfort or pain

Which is worse: a heart attack or cardiac arrest?

From our discussion so far, it seems obvious that cardiac arrest is definitely worse than a heart attack because cardiac arrest can lead to quick death if not reversed right away. However, there are situations where your outcome may be better with cardiac arrest than with a heart attack. So, the right answer to the question is: it depends. In most cases, a heart attack is better than cardiac arrest, because a heart attack is treatable if you seek help right away. With a heart attack, you are usually awake enough to call 911 and get the help you need. You can’t call for help yourself after a cardiac arrest; you need someone to help you right away.

When is cardiac arrest better than a heart attack?

There are certain reversible cases of cardiac arrest that can be revived without any permanent damage. A heart attack applies at least some degree of permanent damage to the heart muscles. In those situations, you may have a better outcome with cardiac arrest than a heart attack. But it doesn’t matter if the cardiac arrest is reversible if there is nobody to revive you when you have a cardiac arrest. That is why the American Heart Association is trying to educate as many people as they can on basic life-saving techniques. They are also trying to make AEDs, or Automatic External Defibrillators, accessible in public locations, so that people with reversible cardiac arrests can be revived.

Another situation when you are better off having a reversible cardiac arrest than a heart attack is when you are hospitalized for an unrelated condition. Most hospitals in the United States have specially-trained medical staff that respond immediately to a cardiac arrest and start the revival. In these situations, it is relatively easy to treat reversible cardiac arrest than a heart attack. Depending on the cause of the cardiac arrest, you may have a better outcome than a heart attack.

What are the causes of cardiac arrests, other than heart attacks?

Many diseases and conditions can cause cardiac arrest. Sometimes, it is related to abnormal electrical activity in the heart, but at other times, it could have normal electrical activity without an actual heartbeat.

Here are several things that can lead to a cardiac arrest:

  1. Abnormal electrical circuit inside the heart
  2. Thickened heart muscles
  3. Heart valve problems
  4. Very high or very low blood potassium
  5. Very low magnesium in the blood
  6. Alcohol-related heart disease
  7. Dilated heart muscles
  8. Infected heart valve
  9. Major blood clot in the lungs
  10. Major tear in the aorta
  11. Bleeding inside the lining of the heart
  12. Bad sepsis with low blood pressure (link to sepsis article here)
  13. Severe internal bleeding
  14. Very low oxygen
  15. Punctured lungs
  16. Drug overdose
  17. Very low blood sugar
  18. Poisoning

It is important to note that not all people with cardiac arrests can be revived. You won’t know who may survive a cardiac arrest until you start CPR and continue it until the paramedics arrive. ER doctors can reassess the situation and make appropriate treatment decisions when patients get there. You can save a life by keeping their blood circulating with CPR until the paramedics arrive.

In conclusion, a heart attack and cardiac arrest are two different things. Get basic CPR training so that you can save someone in cardiac arrest.