Cardiac Arrest

About Cardiac Arrest

Cardiac arrest is the abrupt loss of heart function in a person who may or may not have been diagnosed with heart disease. It can come on suddenly, or in the wake of other symptoms. Cardiac arrest is often fatal, if appropriate steps aren’t taken immediately.

What is cardiac arrest?

Cardiac arrest is the abrupt loss of heart function in a person who may or may not have been diagnosed with heart disease. It can come on suddenly, or in the wake of other symptoms. Cardiac arrest is often fatal, if appropriate steps aren’t taken immediately.

Each year in the United States, more than 350,000 cardiac arrests occur outside of a hospital setting.

Is a heart attack the same as cardiac arrest?

No. The term “heart attack” is often mistakenly used to describe cardiac arrest. While a heart attack may cause cardiac arrest, the two terms don’t mean the same thing.

Heart attacks are caused by a blockage that stops blood flow to the heart. A heart attack (or myocardial infarction) refers to death of heart muscle tissue due to the loss of blood supply. Heart attack can be understood as a “circulation” problem. A heart attack is quite serious, sometimes fatal.

By contrast, cardiac arrest is caused when the heart’s electrical system malfunctions. The heart stops beating properly. Hence the name: The heart’s pumping function is “arrested,” or stopped.

In cardiac arrest, death can result quickly if proper steps aren’t taken immediately. Cardiac arrest may be reversed if CPR (cardiopulmonary resuscitation) is performed and a defibrillator is used to shock the heart and restore a normal heart rhythm within a few minutes.

Learn more about the differences between cardiac arrest and heart attack.

Download our Cardiac Arrest vs. Heart Attack infographic.

Cardiac arrest may be caused by irregular heart rhythms, called arrhythmias. A common arrhythmia associated with cardiac arrest is ventricular fibrillation. Ventricular fibrillation means that the heart’s lower chambers suddenly start beating chaotically and don’t pump blood.

Causes of Cardiac Arrest

Cardiac arrest may be caused by almost any known heart condition.

Most cardiac arrests occur when a diseased heart’s electrical system malfunctions. This malfunction causes an abnormal heart rhythm such as ventricular tachycardia or ventricular fibrillation. Some cardiac arrests are also caused by extreme slowing of the heart’s rhythm (bradycardia).

Irregular heartbeats such as these that can cause cardiac arrest should be considered life-threatening arrhythmias.

Other causes of cardiac arrest include:

• Scarring of the heart tissue Such scarring may be the result of a prior heart attack or another cause. A heart that’s scarred or enlarged from any cause is prone to develop life-threatening ventricular arrhythmias. The first six months after a heart attack represents a particularly high-risk period for sudden cardiac arrest in patients with atherosclerotic heart disease.
• A thickened heart muscle (cardiomyopathy) Damage to the heart muscle can be the result of high blood pressure, heart valve disease or other causes. A diseased heart muscle can make you more prone to sudden cardiac arrest, especially if you also have heart failure. Learn more about cardiomyopathy.
• Heart medications Under certain conditions, various heart medications can set the stage for arrhythmias that cause sudden cardiac arrest. (As odd as it may sound, antiarrhythmic drugs used to treat arrhythmias can sometimes produce ventricular arrhythmias even at normally prescribed doses. This is called a “proarrhythmic” effect.) Significant changes in blood levels of potassium and magnesium (from using diuretics, for example) also can cause life-threatening arrhythmias and cardiac arrest.
• Electrical abnormalities Certain electrical abnormalities such as Wolff-Parkinson-White syndrome and Long QT syndrome may cause sudden cardiac arrest in children and young people.
• Blood vessel abnormalities In rare cases, congenital blood vessel abnormalities, particularly in the coronary arteries and aorta, may cause cardiac arrest. Adrenaline released during intense physical activity often acts as a trigger for sudden cardiac arrest when these abnormalities are present.
• Recreational drug use Use of certain recreational drugs can cause sudden cardiac arrest, even in otherwise healthy people.

Emergency Treatment of Cardiac Arrest

Cardiac arrest can strike without warning

Do you suspect that someone is experiencing cardiac arrest? Here are the signs:

• Sudden loss of responsiveness The person doesn’t respond, even if you tap him or her hard on the shoulders, or ask loudly if he or she is OK. The person doesn’t move, speak, blink or otherwise react.
• No normal breathing The person isn’t breathing or is only gasping for air.

What to do

If you have tried and failed to get the person to respond, and you think the person may be suffering cardiac arrest, here’s what to do:

• Yell for help Tell someone nearby to call 911 or your emergency response number. Ask that person or another bystander to bring you an AED (automated external defibrillator), if there’s one on hand. Tell them to hurry – time is of the essence.
  • If you’re alone with an adult who has these signs of cardiac arrest, call 911 and get an AED (if one is available).
• Check breathing If the person isn’t breathing or is only gasping, administer CPR.
• Give CPR: Push hard and fast Push down at least two inches at a rate of 100 to 120 pushes a minute in the center of the chest, allowing the chest to come back up to its normal position after each push.
• Use an AED Use the automated external defibrillator as soon as it arrives. Turn it on and follow the prompts.
• Keep pushing Continue administering CPR until the person starts to breathe or move, or until someone with more advanced training takes over, such as an EMS team member.

Learn more:

• Learn why the American Heart Association does not endorse “cough CPR,” a coughing procedure widely publicized on the Internet.

The majority of cardiac arrest survivors have some degree of brain injury and impaired consciousness. Some remain in a persistent vegetative state. Determining the survivor's prognosis and making the decision to treat or to withdraw care is complicated and based on many variables (many of which have not been thoroughly studied).

Factors before cardiac arrest:

• Age
• Ethnicity
• Poor health including diabetes, cancer, infection, kidney disease and stroke

Factors during cardiac arrest:

• Time between collapse and start of CPR/defibrillation
• Quality of CPR/defibrillation
• Whether survivor had any neurological function during or immediately after CPR

Factors after cardiac arrest and resuscitation:

• Neurological function: Generally, poor function equals poor prognosis but could be complicated by medical instability and treatments. Some patients suffer a stroke after a cardiac arrest.
• Neurophysiologic function: tests include somatosensory evoked potentials (SSEP) and electroencephalogram (EEG).
• Neuroimaging and monitoring: to determine structural brain injury — such as cranial CT, MRI, magnetic resonance spectroscopy, positron emission tomography (PET) — mostly to exclude hemorrhage or stroke.
• Biochemistry: from blood or cerebrospinal fluid
• Whether therapeutic hypothermia (intentionally lowering the patient's body temperature) was used.

Cardiac Arrest Tools and Resources

Tools and resources related to cardiac arrest.

• Answers by Heart Patient Information Sheets
  • What is an Automated External Defibrillator? (PDF)
  • What is Arrhythmia? (PDF)
  • See all Answers by Heart sheets
• Order Cardiac Arrest and Other Educational Brochures
• Helping people 'Stay Alive' is easy with Hands-Only™ CPR

https://www.heart.org/en/health-topics/cardiac-arr...