Cardiac Arrest

Sport games and Sudden Cardiac Arrest (SCA)

Sudden cardiac arrest (SCA) is a sudden loss of heart function. It is caused by a problem in the heart’s electrical system. The heart beats dangerously fast or stops beating and fails to pump blood to the rest of the body. SCA is different from a heart attack, which involves a blockage in a blood vessel to the heart.

What is Sudden Cardiac Arrest?

Sudden cardiac arrest (SCA) happens when the heart beats dangerously fast or suddenly stops beating. This is a medical emergency and can progress quickly to sudden cardiac death (SCD). If you suspect someone is in sudden cardiac arrest, call 911 and start CPR right away.

When playing sports, an athlete’s heart is working faster and pumping harder. Adrenaline is pumped throughout the body, and the heart needs more oxygen than normal. Dehydration, fever or changes in electrolytes (minerals in the body) can also play a part.

In people whose hearts are not normal to begin with, these extra stresses can sometimes trigger the electrical system of the heart at exactly the wrong time and cause sudden cardiac arrest.

While rare, SCA is the leading medical cause of death in young athletes. Use this condition center to learn more about sports and sudden cardiac arrest.

Signs and Symptoms

More than half the time, sudden cardiac arrest in athletes happens without warning. In these cases, the heart stops beating and the person collapses.

You can tell when someone is in SCA because the individual stops breathing, and no pulse is felt in the neck or wrist (no heartbeat). This is a medical emergency that requires action at once. Call 911 right away and start CPR right away.

When there are warning signs, the person can experience:

  • sudden irregular heartbeat
  • lightheadedness or dizziness
  • chest pain
  • shortness of breath
  • prior episodes of passing out

If you have these symptoms, either with or without exercise, or if you have a family member who suffered an SCA, talk to your health care professional before continuing to exercise or play sports.


Exercise has many good effects on the body. For a small number of people, though, it can cause harm. This is because during exercise higher levels of adrenaline and stress affect your body. Your heart requires more oxygen to function. Also, there may be dehydration and electrolyte problems. If you have a normal heart, you can adjust to these changes. But physical activity can sometimes trigger an abnormal heart rhythm if you have certain types of heart disease.

Exercise may be risky for people who are born with certain heart conditions. In people younger than 35 years old, a genetic heart disease is a common cause of SCA. In these cases, people are born with a mutation in a gene that increases the chances of SCA. Some of these include:

  • heart muscle disorders, such as hypertrophic cardiomyopathy or arrhythmogenic right ventricular cardiomyopathy
  • heart rhythm disorders, such as Wolff-Parkinson-White syndrome, Long QT syndrome, or catecholaminergic polymorphic ventricular tachycardia

Other conditions that increase your risk of SCA:

  • being born with an abnormal heart artery
  • heart infections
  • Marfan syndrome, when the aorta — the main artery of the heart — ruptures

These conditions affect either the electrical or mechanical structure of the heart and may go undetected until sudden cardiac arrest happens. Electrical problems can stop the heart’s contractions. Mechanical problems can prevent blood from leaving the heart so not enough flows to the body and this may lead to an electrical problem. Both kinds of problems may give warning signs such as a racing heart, shortness of breath, chest pain or fainting with exercise.

In athletes older than 35, coronary artery disease is the most common heart condition to be a cause of SCA. But even in people with coronary artery disease, exercise can be safe.

For people with coronary artery disease, there are important benefits to exercise. Physical training lowers blood pressure and helps control diabetes and cholesterol.

Also, taking part in cardiac rehabilitation, an exercise-based program, after a heart attack lowers the chances of another heart attack. During exercise, if you feel chest pain, shortness of breath or dizziness, be sure to contact your physician.

Exercise is a good thing, but it’s important to talk to your doctor before starting an exercise regimen if you have heart disease.

Exams and Tests

Your health care professional will ask you questions about your symptoms and family history. To know if your symptoms are normal or not, it’s important to consider what sports and exercises you do, how long you’ve been doing them, and your exercise intensity.

You should find out if anyone in your family died suddenly, especially at a young age. It’s important to know if you or any of your relatives had episodes of passing out for no reason, drowning, car accidents, or seizures. These all may have been due to a heart condition.

Typically, your physician will obtain a thorough personal and family medical history and perform a physical exam. Long-term endurance athletes may have a slow pulse. Your health care professional also may listen closely to your heart for any murmurs.

Depending on your history and exam findings, she may recommend other diagnostic tests. The goal of these tests is to identify and treat the problems that might increase your risk of sudden cardiac arrest. Common tests include:

  • Electrocardiogram (ECG). Your ECG should be interpreted with the knowledge that you are an athlete. People who exercise a lot, especially when young, may have an ECG that would look abnormal if you were a non-athlete.
  • Echocardiogram (echo). An echocardiogram, or ultrasound of the heart . This test doesn’t hurt and shows the size and function of the heart. It can also look at the heart valves. For a more detailed look at your heart, your doctor may order a cardiac MRI (magnetic resonance imaging).
  • Home ECG Monitor. If your heartbeat has been fast or irregular or if you have passed out, your doctor may want you to wear an ECG monitor at home. This may be for only one day or up to 30 days, depending on how often you have your symptoms. Some of these monitors are called Holter monitors and some are called event monitors.
  • Stress Test. If symptoms occur during exercise, you may undergo a stress test when you run on a treadmill attached to an ECG. This can mimic the exercise that triggers your symptoms. Sometimes your doctor may also want to do this test using an echocardiogram or a nuclear medicine image. Another test may be a coronary calcium score. Interestingly, higher levels of exercise increase the amount of calcium and plaques in the arteries of the heart, but people in this situation are less likely to have a heart attack.

Genetic Testing may be recommended in specific cases. This requires either a cheek swab or blood work.

In rare cases, your doctor may do an electrophysiology study (EPS) to find out whether you have an issue with your heartbeat.

Playing Sports If You Are at Increased Risk

Health benefits of exercise are well known and proven. Exercise lowers cholesterol levels, aids in regulating blood sugar, helps with depression, supports a healthy weight and prolongs life. But exercise may be riskier for some than for others. If you are diagnosed with a heart condition, you should talk to your doctor about how best to go back to exercising.

In the past, patients with heart conditions were automatically told not to play sports. In recent years, research has shown that many people with heart conditions can participate in sports, with very low risk, under the right circumstances. You and your doctor will decide on the intensity of your sports participation and how closely you should be monitored. There may be recommendations about staying well hydrated, avoiding a fever, and watching electrolytes.

On your part, be sure to take the medications prescribed by your doctor. If you are an athlete with heart disease who has chosen to continue, with your doctor’s guidance, it is important to have a plan in place should an emergency occur. You should choose sports venues that are equipped to provide the best possible care if a medical emergency does arise.

We all have seen news articles about people dying suddenly during sports, but for many people with heart conditions, it can be OK to play again. Talk to your doctor about what is best for you.

Cardiac Arrest

Treatment and Preventions of sudden cardiac Arrest


The only effective treatment for sudden cardiac arrest, SCA, is as soon as possible to restore the heart’s normal rhythm by using an automated external defibrillator, or AED, to deliver a shock to the heart. For every minute that passes without treatment, a person’s chance of surviving drops by 7% to 10%.  

People who happen to be in the area during the event play a critical role in saving lives. Their action can mean the difference between life and death.

What to Do?

  1. Call 911 or have someone else call if other people are available.
  2. Start CPR at once while waiting for emergency help to arrive.
  3. Ask another person to find the nearest AED. AEDs are portable devices found in EMS vehicles and public places. They give simple instructions and are programmed to identify an electrical problem and shock the heart.  

People who survive an SCA need advanced emergency and cardiac care. Doctors will use basic cardiac testing to identify the cause of SCA, and adjust treatment.

For some patients, an implantable cardioverter defibrillator (ICD) placed under the skin may be needed. ICDs can detect an abnormal rhythm and send low shocks to the heart to restore a normal heartbeat.


Because most cases of sudden cardiac arrest, SCA, occur in people who have had a heart attack, or who have hearts with lowered ability to pump blood (called a low ejection fraction) or heart failure, health care teams can take steps to prevent a repeat event.

It is critical that people who survive sudden cardiac arrest follow their treatment plan.Otherwise, the best approach is to live a healthy lifestyle by:

  • Eating a diet low in saturated and trans fats, and high in soluble fiber and fruits and vegetables
  • Exercising regularly
  • Getting to a healthy weight and keeping it
  • Managing stress
  • Quitting smoking

What Else Can You Do?

Know how to respond if someone is in sudden cardiac arrest. Survival rates could double or triple if more people take action and know what to do, according to the Sudden Cardiac Arrest Foundation.

  • Know the warning signs of an SCA.
  • Act fast. Chance of survival goes down for every minute treatment is delayed. Don’t waste time debating whether it’s SCA.
  • Take a CPR class or brush up on your skills if you’ve taken one.
  • Learn how to use an automated external defibrillator (AED), and where they can be found.

Keep in mind:

  • AEDs are not in all places. Do not delay CPR or calling 911 if an AED is not available.
  • AEDs at home don’t seem to affect survival. This could be because many who have an SCA at home are alone.
Cardiac Arrest

Signs and Symptoms of sudden cardiac arrest

Sudden cardiac arrest tends to happen without warning. Usually, the first sign is someone fainting, collapsing or seeming to be lifeless. You may not be able to feel a pulse. It’s critical to call 911 right away.

Recent studies of SCA survivors find that, in some cases, people remember that something didn’t feel quite right beforehand. They recalled:

  • Dizziness
  • Unexplained shortness of breath
  • Chest pains
  • Seizures (usually in the arms and legs)
  • Feeling sick to the stomach or vomiting an hour before the event

Another study shows that half of patients ages 35 to 65 had warning signs — mainly chest pain and shortness of breath in the 24 hours before the SCA. Some had warning signs for weeks.

What Increases Your Risk?

Why sudden cardiac arrest happens is not clearly understood. It is most often caused by a dangerous heart rhythm called ventricular fibrillation.

SCA can happen to anyone at any age. But the risk is greater among certain people. For example, it is more likely if you’ve had an SCA. And it’s more likely if a parent, child or sibling has had one. Men and African Americans also are at greater risk.

Still, certain diseases or conditions can cause the heart’s electrical system to misfire and lead to SCA. These include:

• Coronary heart disease
• Structural changes in the heart, for example, a thickened heart muscle/enlarged heart
• Heart failure with reduced pumping function, often referred to as a low ejection fraction (ejection fraction less than 35%)
•  Heart attack – 75% of people who suffer sudden cardiac arrest were found to have had a heart attack, many of which went undiagnosed; survivors of heart attack are 4 to 6 times more likely to have SCA than the general population
• Physical stress such as trauma, blood loss, dehydration/electrolyte imbalance or (in rare cases) very intense physical activity
• Heart problems you are born with make you more prone to heart rhythm problems.

Cardiac Arrest

Sudden Cardiac Arrest

Sudden cardiac arrest (SCA) happens when the heart suddenly stops beating. It happens without warning. Someone may seem fine one minute and collapse the next.

Sudden cardiac arrest is a medical emergency. You should dial 911 and start CPR right away if you suspect SCA in someone.

Without quick action to revive the heart, a person can die in minutes. But delivering an electric shock to restore a normal heartbeat as soon as possible and giving CPR can be lifesaving.

If another person is available, ask him or her to look for an automated external defibrillator (AED). An AED is a portable device that can detect a harmful change in the heart’s rhythm (arrhythmia) and give an electric shock, called defibrillation. AEDs are available in many locations including shopping centers, sports venues, airports, community centers and office buildings.

Giving CPR and using an AED within the first few minutes of SCA can greatly improve the chances of survival.

SCA: What it is and isn’t

Sudden cardiac arrest is different from a heart attack.

During a heart attack …During sudden cardiac arrest …
Blood supply to the heart muscle is reduced or blocked, but the heart keeps beating; however, there may be damage to the heart muscle.The electrical system of the heart goes wrong (think of the way the lights flash before the power goes out), and the heart stops pumping blood.
Usually, the person knows something is happening, and can talk about his or her symptoms.Usually, the person is unconscious, and a pulse may not be found.

In some cases, a heart attack might trigger the electrical issues that cause sudden cardiac arrest. But these events don’t need to happen at the same time.

Sudden cardiac arrest can happen in people without heart disease. About 80% of cases are due to existing coronary artery disease. However, in most cases SCA is the first sign of a heart problem. That is, those affected were unaware of their heart disease until they had sudden cardiac arrest.