Sudden Cardiac Death

What is sudden cardiac death?

Sudden cardiac death (SCD) is sudden, unexpected death within an hour due to a heart issue. Performing CPR can double someone’s chances of surviving. Cardiac arrest can lead to sudden cardiac death.

What happens during sudden cardiac death?

When you have a sudden cardiac arrest, your heart stops pumping oxygen-rich blood out to your body. This means your organs can’t receive any oxygen, which they need to function and keep you alive. Without immediate help to get oxygen to your brain and other vital organs, this is fatal. At that point, it becomes sudden cardiac death.

How common is sudden cardiac death?

Sudden cardiac death is the leading cause of natural death in the United States. It causes half of all heart disease deaths.

Every year, more than 356,000 people in the United States have a cardiac arrest outside a hospital. Only about 10% of them survive, even with paramedic treatment.

Sudden cardiac death affects men and people assigned male at birth (AMAB) twice as often as it does women and people assigned female at birth (AFAB). It’s rare in children, affecting only 1 to 2 per 100,000 children each year.

Are there signs before sudden cardiac death?

Yes, some sudden cardiac death symptoms may happen hours or weeks before sudden cardiac death, like:

1. Abnormal vital signs.
2. Heart attack.
3. Severe infections (sepsis).
4. Fatigue.
5. Shortness of breath.
6. Chest pain.
7. Fainting.
8. Heart palpitations.

If you notice any of these, seek emergency care right away.

What causes sudden cardiac death?

Coronary artery disease is the most common cause of sudden cardiac death.

An abnormal heart rhythm (arrhythmia) most often causes sudden cardiac death in people younger than 35. Congenital (since birth) heart issues or genetic conditions that affect your heart’s electrical system often cause the arrhythmia.

Most professional sports programs screen athletes for the most common cause of sudden cardiac death in that population. In the United States, that’s hypertrophic cardiomyopathy (a thickened heart muscle that especially affects your ventricles). Sudden cardiac death in athletes is rare (about 1 to 6 in 100,000 athletes younger than 35).

In people 35 and older, the cause of sudden cardiac death is more often related to coronary artery disease.

Besides coronary artery disease and arrhythmia, other sudden cardiac death causes include cardiomyopathy from having:

• Alcohol use disorder.
• Obesity.
• Genetic disorders of your heart muscle, including hypertrophic cardiomyopathy and arrhythmogenic cardiomyopathy.

What are the risk factors for sudden cardiac death?

Sudden cardiac death has many risk factors. But you’re more likely to have a higher risk as you age and if you’re Black and assigned male at birth (AMAB). Certain genetic causes of heart disease like hypertrophic cardiomyopathy also increase the risk of sudden cardiac death.

Many factors can increase your risk of sudden cardiac arrest and sudden cardiac death. The two leading risk factors include:

• Previous heart attack: Your risk of sudden cardiac death is higher after a heart attack.
• Coronary artery disease: Risk factors for coronary artery disease include smoking, family history of cardiovascular disease, high cholesterol or an enlarged heart.

Other risk factors include having:

• A prior episode of sudden cardiac arrest.
• A family history of sudden cardiac arrest or sudden cardiac death.
• A personal or family history of certain abnormal heart rhythms, including long QT syndrome, Wolff-Parkinson-White syndrome and ventricular tachycardia.
• Ventricular tachycardia or ventricular fibrillation after a heart attack.
• A history of congenital (since birth) heart issues or blood vessel abnormalities.
• A history of syncope (fainting episodes of unknown cause).
• Heart failure (when your heart’s pumping power is weaker than normal). People with heart failure are six to nine times more likely than most people to have ventricular arrhythmias that can lead to sudden cardiac arrest.
• Dilated cardiomyopathy (causes about 10% of sudden cardiac deaths). Scarring and damage to your heart muscle increase the chance of abnormal heart rhythms. This can also lead to heart failure.
• Hypertrophic cardiomyopathy.
• Significant changes in blood levels of potassium and magnesium.
• Obesity.
• Diabetes.
• A history of taking recreational drugs or drugs that can cause arrhythmias.

If you have any of these risk factors, talk with a healthcare provider about how to reduce your risk.

How is sudden cardiac death diagnosed?

A healthcare provider can confirm sudden cardiac death after ruling out death from other causes. They may suspect sudden cardiac arrest leading to sudden cardiac death if you:

• Weren’t breathing.
• Didn’t have a pulse.
• Weren’t conscious.

How can I lower my risk of sudden cardiac death?

You can reduce your risk in many ways, like:

• Keeping your regular follow-up appointments with your healthcare provider.
• Making healthy lifestyle changes such as getting to a weight that’s healthy for you, being physically active and eating a low-fat diet.
• Avoiding all tobacco products.
• Taking medications your healthcare provider prescribes for high cholesterol or arrhythmia.
• Getting an implantable cardioverter defibrillator (ICD) if your healthcare provider recommends it.
• Having procedures or surgery your provider recommends, like angioplasty or catheter ablation.
• Having genetic testing (if your provider recommends it) to look for potential causes of sudden cardiac death.
• Teaching your family the importance of immediate care and learning CPR.

Competitive athletes should undergo prescreening annually for a heart condition. This should include an evaluation of their personal and family history (updated each year) and a physical exam. Their sports physician may recommend more testing if the first evaluation has any concerning findings.

If your healthcare provider suspects a heart problem, you should get a referral to a cardiologist.

What is the difference between a heart attack and sudden cardiac death?

A heart attack is an issue with oxygen-rich blood reaching your heart muscle. Sudden cardiac death happens when someone can’t revive you after your heart stops beating.

A blockage in your coronary arteries (which supply blood to your heart muscle) causes a heart attack. An electrical issue with your heart’s signaling system causes a sudden cardiac arrest and possibly sudden cardiac death. While a heart attack can lead to sudden cardiac death, there are other causes of sudden cardiac death.

How quick is sudden cardiac death?

A cardiac arrest leaves you without enough blood flow to your brain. This can make you unconscious in just seconds. Sudden cardiac death can happen in a few minutes.