What are sudden cardiac arrest and sudden cardiac death?
Sudden cardiac arrest (SCA) means your heart suddenly stops beating, usually without warning. Without immediate treatment, SCA can cause sudden cardiac death (SCD). Sudden cardiac death is the most common cause of death in the United States and many other countries.
How is SCA different from a heart attack?
Sudden cardiac arrest is not a heart attack. When you have a heart attack, your heart keeps beating, but it can’t get enough blood because of blockages in the coronary arteries. As a result, your heart muscle can be damaged.
Sudden cardiac arrest is caused by a problem with your heart’s electrical system. Impulses that control your heartbeat get erratic. Your heart beats dangerously fast and then stops. This stops your blood flow, usually causes you to lose consciousness, and can lead to brain damage or SCD.
What are the symptoms of SCA?
Many people who have SCA do not have symptoms. Others feel their heart racing or get dizzy as their heartbeat gets out of control.
If someone has SCA, they need emergency treatment. Call 911 and start CPR, or if possible, use an automated external defibrillator (AED) to shock their heart back into a normal rhythm. Cardiopulmonary resuscitation can keep enough oxygen in the lungs and brain until the heart can be shocked back into a normal rhythm. Many public areas have automated external defibrillators (AEDs).
The survival rate is as high as 90% if you get emergency treatment in the first minutes after SCA starts. The survival rate drops about 10% per minute. The risk of death is almost certain without emergency treatment.
What causes SCA?
The most common cause of SCA is ventricular fibrillation. This is an abnormal heart rhythm that starts in the heart’s lower chambers (ventricles). It causes an erratic, fast heartbeat, and stops blood flow to your body.
Who is most likely to have SCA?
Many things can put you at risk of having SCA and SCD. The biggest risk factors are:
- A previous heart attack Your risk of SCD is higher in the first 6 months after a heart attack, and 75% of people who have SCD have had a heart attack. It is possible to have had a heart attack without having symptoms.
- Coronary artery disease. Most (80%) of people who have SCD have coronary artery disease.
Other risk factors for SCA and SCD are:
- Male gender. More men have SCA and SCD than women do.
- Age. Your risk is higher as you get older.
- Abnormal heart rhythm (arrhythmia) or a family history of arrhythmias, including long QT syndrome, Wolff-Parkinson-White syndrome, extremely low heart rate or heart block.
- Previous SCA or a family history of SCA or SCD.
- Heart failure, especially if your ejection fraction is less than 40% and you have ventricular tachycardia.
- Congenital heart defects or abnormal blood vessels.
- History of fainting without knowing the cause.
- Dilated cardiomyopathy (the left ventricle stretches out, gets weak, and your heart can’t pump enough blood to your body).
- Hypertrophic cardiomyopathy (thick heart muscle, especially in the ventricles).
- Significant changes in the levels of potassium and magnesium in your blood.
- Obesity.
- Diabetes.
- Substance Use Disorder.
There is also research that shows your risk of SCA and SCD is higher if you are black, especially if you have health problems like chronic kidney disease, diabetes, heart failure and high blood pressure.
What can I do to prevent SCA and SCD?
Talk to your healthcare provider about your risk of SCA and SCD. You may need to have tests to check for heart problems, make lifestyle changes, take medicine or have a procedure to reduce your risk of heart problems, including SCA and SCD.
Manage health conditions
It is important to control health problems that put you at risk for SCA and SCD. This includes following your plan of care and keeping all appointments for follow-up visits and tests.
Live a heart-healthy lifestyle
This includes managing your cholesterol levels, weight, blood pressure and diabetes. You should also make changes as needed:
- Don’t smoke or use tobacco products.
- Eat a heart-healthy diet.
- Exercise most days of the week.
Medicine
You may need medicine to control your cholesterol levels, help your heart beat normally or work as well as it can. If your healthcare provider prescribes medicine, it is important to take it exactly as prescribed. Do not stop or start taking any medicine or supplement without talking to your healthcare provider.
Devices
If your risk of SCA or SCD is very high, your doctor may talk to you about getting an implantable cardioverter-defibrillator (ICD). This is a small device that goes under your skin. It monitors your heart rate and uses an electric shock to correct abnormal heart rhythms.
Procedures and surgery
If you have coronary artery disease or another heart problem, your healthcare provider may talk to you about procedures or surgery to correct the problem and reduce your risk of SCA and SCD. For example, angioplasty/stenting and coronary artery bypass graft surgery are used to restore blood flow to your heart. Catheter ablation and cardioversion are procedures to correct abnormal heart rhythms.
Talk to your family and friends
If your risk for SCA and SCD is high, make sure those close to you know the signs of a problem and how important it is to call 911. They should also learn CPR and how to use an AED.
Sudden Cardiac Death and Athletes
You may have seen or heard news stories about athletes who have SCD. It is not common for athletes to have SCD, but because cases are often reported, it can seem common.
Many people who have SCD have heart disease they don’t know about.
Younger athletes
Sudden cardiac death affects about 1 in 100,000 to 300,000 young athletes — mostly males involved in team sports. Many of them are born with heart problems they don’t know about.
Older athletes
Running is the most common activity to trigger SCD among athletes aged 35 and older. About 1 in 15,000 joggers and 1 in 50,000 marathon runners have SCD that is often linked to coronary artery disease.
Screening
The American Heart Association recommends cardiovascular screening for high school and collegiate athletes. The screening should include a physical exam and complete evaluation of the athlete’s personal and family history.
If you are a man who is 40 or older or a woman 50 or older, you should have an exercise stress test and get education about cardiac risk factors and symptoms before taking part in sports.
If the screening shows signs of a heart problem, see a cardiologist for an evaluation and possible treatment before you start your activity.
For More Information
Sudden Arrhythmia Death Syndromes Foundation
A nonprofit organization established to help prevent sudden and unexpected cardiac death in children and young adults.
4527 South 2300 E
Suite 104
Salt Lake City, UT 84117
1.800.272.3023
sads.org
Heart Rhythm Society
1325 G Street NW, Suite 400, Washington D.C. 20005
202.464.3400
HRSonline.org
CPR
For more information about CPR, please contact your local chapter of the American Red Cross or the American Heart Association, or ask your doctor for more information.
