How is Cardiac Arrest Diagnosed?


Since cardiac arrest occurs suddenly and unexpectedly, the condition is often diagnosed after an episode occurs. If a person survives cardiac arrest, diagnostic tests are performed to determine its cause and help prevent future cardiac arrest episodes.

Diagnostic tests include:

  • Electrocardiogram - Also known as an EKG or ECG. Electrode sensors are placed on the chest and sometimes the arms and legs. The electrodes detect and record information about heart activity and electrical impulses in the heart. This test provides an easy, painless way for a doctor to check for irregularities that could lead to sudden cardiac death.
  • Blood tests - A doctor can analyze a blood sample to detect abnormal levels of potassium, magnesium, hormones, and other chemicals that influence the electrical signals in the heart. Blood tests can also measure certain enzyme levels that are indicators of heart damage or a heart attack.
  • Imaging tests, including:
    • Echocardiogram - A doctor uses a wand-like instrument that emits ultrasound waves to produce computerized images of the heart in motion. This enables the doctor to detect structural or blood flow issues within the heart and damage or abnormalities in the heart muscle or valves that may lead to cardiac arrest.
    • Chest X-ray - Uses radiation to produce images of the heart and surrounding blood vessels. The X-ray can reveal the size and shape of the heart, fluid accumulation around the heart, or issues with valves.
    • Nuclear scan - Trace amounts of a radioactive substance are injected into the bloodstream. Specialized cameras can detect the radioactive substance in the blood as it flows throughout the body, allowing doctors to detect blood flow issues that may lead to cardiac arrest.
    • Coronary catheterization - A thin tube is fed through a blood vessel to the heart and injects a liquid dye into the bloodstream. X-ray images are then used to view the dye and detect artery blockages and blood flow issues.

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How is Cardiac Arrest Treated?


Because of its sudden nature, you should immediately contact 911 if you or someone else is experiencing symptoms of cardiac arrest. Immediate treatment for cardiac arrest may involve:

  • CPR - Involves repeated compressions of the chest performed by another individual. This can help maintain blood and oxygen flow to vital organ systems within the body until more advanced treatment or help is available.
  • Defibrillation - A device called a defibrillator sends an electrical shock through the chest to the heart. This can stabilize an individual by restoring a normal heartbeat. First responders and medical personnel can use a defibrillator. However, these devices are also available in certain public spaces, like schools and exercise facilities, to treat a person experiencing cardiac arrest until emergency services arrive.
  • Medications - A combination of CPR and life support medications may be given to patients who have experienced cardiac arrest

Once a cardiac arrest patient is brought to the hospital, treatment methods may include:

  • TTM - Involves reducing an individual's core body temperature to minimize the potential damage caused by hypoxia or lack of sufficient oxygen in the blood and tissues to sustain bodily functions
  • Oxygen therapy - A doctor can recommend this to supplement the amount of oxygen in your body after cardiac arrest. Your heart may be weakened after such an incident, which can result in your body not getting the amount of oxygen it needs. This can be administered through a mask or nasal cannula (tubes that rest inside the nose) or intubation.
  • ECMO, or extracorporeal membrane oxygenation -Involves pumping blood to a heart-lung machine to remove carbon dioxide from the blood and return oxygenated blood back into the body. This can be used to assist your heart and lungs in delivering oxygen to your tissues.
  • Percutaneous left ventricular device - May be used as an alternative to ECMO. These devices are connected to the circulatory system by inserting tubes into a femoral artery and can help the heart to work until it has been repaired.

Long-term treatment methods can be used to reduce the risk of having another cardiac arrest episode. These may include:

  • Medications - Including anti-arrhythmic drugs such as beta-blockers or ACE (angiotensin-converting enzyme) inhibitors
  • ICDs - Devices implanted under the skin, usually in the chest. They monitor an individual's heartbeat and can sense potentially dangerous abnormalities in your heart rhythm. The ICD can deliver electrical impulses to help your normal heartbeat to continue if complications or irregularities are detected.
  • Coronary angioplasty - This procedure opens up arteries that are clogged or narrowed. It involves inserting a catheter into the blocked blood vessel with a balloon on its tip. This balloon is then inflated, pressing the blood clot or plaque against the artery's sides, allowing blood flow to increase. Learn more about how we've expanded our cardiac catheterization practice.
  • Coronary bypass surgery - Allows blood flow to be redirected around a blocked artery in your heart. This procedure uses a blood vessel taken from another part of the body and connects it so that blood flow can be rechanneled around the blockage.
  • Catheter ablation - Involves electrode catheters being guided through your veins to various positions in the heart. The electrodes then either use cold temperatures (cryoablation) or radiofrequency waves (radiofrequency ablation) to burn tissue and block abnormal electrical impulses in the heart that may lead to cardiac arrest.
  • Corrective heart surgery - May be recommended to mend faulty valves, diseased or damaged heart tissue, or congenital heart deformities to reduce the risk of cardiac arrest due to life-threatening arrhythmias



Over 350,000 people in the United States experience cardiac arrest yearly, and only about 10% of people survive. However, if treatment like CPR is administered immediately, the survival rate can double or possibly even triple.

Cardiac arrest occurs quickly, so someone may suddenly collapse, lose consciousness, and stop breathing. Just before cardiac arrest, a person may feel chest pain or discomfort and may experience shortness of breath. Some people feel dizzy, nauseous, fatigued, and can even pass out just before a cardiac arrest episode.

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