If you see that someone is experiencing symptoms of cardiac arrest, contact 911 immediately.

What is Cardiac Arrest?

What is Cardiac Arrest?

Cardiac arrest is when the heart suddenly stops beating. During cardiac arrest, oxygen-rich blood cannot reach the brain and other organs, resulting in unconsciousness or even death if not treated immediately. Also known as sudden death, this condition is usually caused by an issue with the electrical signals in the heart.

Cardiac arrest is a common cause of death and is responsible for about 350,000 deaths in the U.S. annually. A defibrillator is a device that sends an electrical shock to the heart to restore normal rhythm. These devices are sometimes accessible in public places and can help treat a person having cardiac arrest until emergency responders arrive.

Cardiopulmonary Resuscitation (CPR) can also be performed to increase a person's chances of surviving cardiac arrest.

Cardiac arrest vs. heart attack

Malfunctioning electrical signals in the heart cause cardiac arrest. This malfunction can cause the heart to beat abnormally or cause the ventricles (the heart's lower chambers) to quiver. When the heart stops, it can’t adequately pump oxygen-rich blood to the rest of the body.

In contrast, heart attacks are caused by a blockage in one of the major blood vessels connected to the heart. This prevents the heart from receiving oxygen-rich blood and may trigger fatal electrical signals resulting in cardiac arrest.

Signs & Symptoms of Cardiac Arrest


Symptoms of cardiac arrest happen quickly and require immediate care. They may include:

  • Loss of consciousness
  • Inability to breathe
  • No pulse
  • Sudden collapse

Some symptoms may occur before cardiac arrest begins. These are "warning signs" of cardiac arrest and should be taken seriously. These may include:

  • Shortness of breath or gasping for air
  • Chest pain
  • Fatigue
  • Dizziness
  • Nausea
  • Rapid heart rate
  • Heart palpitations, including a fluttering or pounding heart

What Causes Cardiac Arrest?


Causes of cardiac arrest include:

  • Arrhythmias - Irregular heart rhythms caused by malfunctioning electrical signals in the heart. They can cause the heart to beat too quickly, slowly, or abnormally. In particular, the most common cause of cardiac arrest is ventricular fibrillation, which causes the heart's ventricles to quiver rather than fully pump blood to the rest of the body.
  • Coronary artery disease - Coronary arteries are the blood vessels that supply oxygen-rich blood to the heart. When the coronary arteries are blocked or narrowed by the accumulation of fatty materials, the heart cannot get the oxygen it needs to function properly, leading to cardiac arrest.
  • Valvular heart disease - Valves regulate blood flow between the different parts of the heart. When valves leak or narrow, they put extra strain on the heart and increase the risk of arrhythmia and cardiac arrest.
  • Congenital heart conditions - Heart conditions that are present from birth. This may include heart defects such as having a hole in the heart or issues with heart valves or blood vessels around the heart.
  • Cardiomyopathy (enlarged heart) - Occurs when the heart's muscle thickens, leading to abnormal muscle contractions
  • Heart attack - Can trigger sudden cardiac arrest. Also, a heart attack can leave scar tissue that disrupts normal heart rhythm and thus increases the likelihood of cardiac arrest.
  • Severe physical stress - This includes traumatic events that cause a lack of oxygen, like choking or drowning. This also includes severe blood loss, which disrupts the heart's ability to pump oxygenated blood to different body parts. Also, severe electrical shocks can interrupt the electrical signals that control the heart's muscle motion and cause cardiac arrest.

Risk Factors for Cardiac Arrest

Risk Factors

Certain factors can increase the risk of sudden cardiac arrest. Some of these risk factors are influenced by lifestyle choices and behaviors, while others may be impacted by family health history. Cardiac arrest risk factors include:

  • Heart conditions – Heart conditions, including coronary artery disease, congenital heart conditions, valve problems, arrhythmias, and cardiomyopathy, can disrupt normal blood flow, alter heart rate, and strain the heart
  • Previous heart attacks - The resulting scar tissue on the heart muscle can disrupt its proper functionality
  • Family history – Family history of heart disease, arrhythmias, or cardiac arrest increases a person's risk of cardiac arrest. Certain inherited genes within families are also associated with issues in the heart's electrical system, thus increasing the likelihood of cardiac arrest.
  • Age - The risk of cardiac arrest increases with age. Cardiac arrest rarely occurs in people younger than 30 years old.
  • Sex - Cardiac arrest is more common in men—the risk for women increases after menopause
  • Race - The risk of cardiac arrest is twice as high for black people compared to white people, and black women are at a higher risk than black men. The risk is lower for Hispanic and Asian people.
  • High blood pressure - The force of blood against your blood vessel walls is higher than normal
  • High cholesterol – Can cause fatty deposits to build up in blood vessels, making it more difficult for the heart to pump blood to other body parts
  • Obesity - Changes in body composition due to obesity can affect heart structure and functionality
  • Diabetes - People with diabetes have an increased risk of cardiac arrest. This is partly due to abnormalities in blood vessels but also because diabetes correlates with other risk factors, such as obesity, high blood pressure, and high cholesterol.
  • Chronic kidney disease (CKD) - As the stage of CKD increases, so does the risk of sudden cardiac death
  • Use of recreational drugs – Such as cocaine and amphetamines. These drugs increase blood pressure and heart rate, putting strain on the heart.
  • Certain medications - Some antibiotics and diuretics can intensify arrhythmias and increase the risk of cardiac arrest
  • Abnormal potassium and magnesium levels - These minerals help the heart's electrical system function properly, so low levels can increase the risk of cardiac arrest
  • Smoking - The risk of cardiac arrest and other heart-related issues is higher in people who smoke
  • Sleep apnea - Causes irregular heart rhythms and decreased oxygen levels, putting extra stress on the heart

Certain behaviors like excessive alcohol consumption, extreme physical exertion, severe emotional trauma, or recent influenza infection can act as triggers of cardiac arrest, particularly in individuals who already have existing heart conditions. Still, even people without any of these risk factors can experience cardiac arrest.



There is no guaranteed way to prevent cardiac arrest, but certain measures can be taken to maintain a healthy lifestyle and reduce your risk:

  • Engage in regular exercise
  • Have a balanced diet low in trans and saturated fats and rich in vegetables, fruits, and lean proteins
  • Avoid smoking and drug use
  • Regularly visit your doctor; get screened for heart disease and medical complications that can lead to cardiac arrest
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Trust NewYork-Presbyterian for Cardiac Care

The healthcare professionals at NewYork-Presbyterian are experts in the diagnosis and treatment of heart diseases and medical conditions that can lead to cardiac arrest. Make an appointment today to speak with one of our heart health specialists.