If you witness someone experiencing sudden cardiac arrest, immediately dial 9-1-1 or call your local emergency personnel and initiate CPR. If done properly, CPR can save a person’s life, as the procedure keeps blood and oxygen circulating through the body until help arrives.

If an AED (Automated External Defibrillator) is available, the best chance of rescuing the patient includes defibrillation with that device. The shorter the time until defibrillation, the greater the chance the patient will survive. It is CPR plus defibrillation that rescues the patient.

Once emergency personnel arrive, defibrillation can be used to restart the heart. This is done through an electric shock delivered to the heart through paddles placed on the chest.

After successful defibrillation, most patients require hospital care to treat and prevent future cardiac problems.

Can sudden cardiac arrest be prevented?

If you have any of the risk factors listed above, it is important to speak with your doctor about how to reduce your risk.

Keeping regular follow-up appointments with your doctor, making certain lifestyle changes, taking medications as prescribed and having interventional procedures or surgery (as recommended) are ways you can reduce your risk.

Follow-up care with your doctor:

Your doctor will tell you how often you need to have follow-up visits. To prevent future episodes of sudden cardiac arrest, your doctor will want to perform diagnostic tests to determine what caused the cardiac event. Tests may include electrocardiogram (ECG or EKG), ejection fraction, ambulatory monitoring, echo-cardiogram, cardiac catheterization and electrophysiology study.

Ejection fraction (EF):

Ejection fraction is a measurement of the percentage of blood pumped out of the heart with each beat. Ejection fraction can be measured in your doctor’s office during an echocardiogram (echo) or during other tests such as a multiple gated acquisition (MUGA) scan, cardiac catheterization, nuclear stress test or magnetic resonance imaging (MRI) scan of the heart.

The Ejection fraction of a healthy heart ranges from 55 to 65 percent. Your Ejection fraction can go up and down, based on your heart condition and the effectiveness of the therapies that have been prescribed.

If you have heart disease, it is important to have your Ejection fraction measured initially, and then as needed, based on changes in your condition. Ask your doctor how often you should have your Ejection fraction checked.

Reducing your risk factors:

If you have coronary artery disease (and even if you do not) there are certain lifestyle changes you can make to reduce high blood pressure and cholesterol levels and manage your diabetes and weight, thereby reducing your risk of sudden cardiac arrest.

These lifestyle changes include:

  • Quitting smoking
  • Losing weight if overweight
  • Exercising regularly
  • Following a low-fat diet
  • Managing diabetes
  • Managing other health conditions

If you have questions or are unsure how to make these changes, talk to your doctor.

Patients and families should know the signs and symptoms of coronary artery disease and the steps to take if symptoms occur.


To help reduce the risk of sudden cardiac arrest, doctors may prescribe medications to patients who have had heart attacks, or who have heart failure or arrhythmias. These medications may include angiotensin- converting enzyme (ACE) inhibitors, beta blockers, calcium channel blockers and other antiarrhythmics. For patients with high cholesterol and coronary artery disease, statin medications may be prescribed.

If medication is prescribed, your doctor will give you more specific instructions.

Last reviewed by a Cleveland Clinic medical professional on 05/14/2019.

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