What is the cause of Sudden Cardiac Arrest

What is the cause of Sudden Cardiac Arrest?

It happens every 90 seconds in America.

It strikes those young and old, caring little for race, gender, status, or lifestyle. And it’s unpredictable.

Roughly 1 in every 900 people will suffer a Sudden Cardiac Arrest this year alone. That’s 75 fans at a NFL football game with average attendance.

And it’s why it ranks among the top killers of Americans today.

But what is the cause of Sudden Cardiac Arrest? Who is at risk and how do we protect our loved ones?

Related: How to Respond to a Sudden Cardiac Arrest

Sudden Cardiac Arrest occurs when something in the heart’s electrical system malfunctions, causing the heart to stop beating and cease pumping blood, while halting a victim’s breathing. At this point, a person collapses and can die if left untreated.

The cause of this medical emergency is often a heart condition the victim was unaware they even had, with no symptoms presenting itself until the actual cardiac arrest. These conditions can be caught and corrected, however, with proper preventative heart screenings.

What are the Causes of Sudden Cardiac Arrest

An abnormal heart rhythm is the initial cause of an electrical malfunction in the heart, leading to a Sudden Cardiac Arrest.

The following are common conditions that can trigger this event, but not an exhaustive list:


Perhaps one of the most common hidden heart conditions, Cardiomyopathy causes the heart to become enlarged, often weakening the muscles during heavy activity because of the strain.

When a person is involved in sports or other high energy activities, the strain to the weakened muscles can often cause an SCA, leading to sudden death. When caught early, activity restrictions are often put in place to avoid straining the heart muscles, thus saving a young life.

Cardiomyopathy is an inherited condition but can also be contracted from viral infection or as the result of chemotherapy for cancer. It is presently the leading cause of cause of SCA among youth and was spotlighted this past summer in a number of our #WhyItMatters feature posts.

Long QT & Brugada Syndrome

These two syndromes account for a large percentage of SCA related deaths.

Both cause fast or irregular heartbeats, usually in response to exercise or stress. This can in turn lead to what is called an arrhythmia. When this happens, the heart struggles to pump blood to vital organs like it needs to in order to survive. An arrhythmia leads to a cardiac arrest, and ultimately death, because of the malfunction of the heart.  

Related: After daughter dies from Long QT related SCA death, mother works to change culture for preventative heart screenings

Coronary Artery Disease or Ischemic Heart Disease

When your coronary arteries become blocked with plaque, the flow of blood to the heart in inhibited, often causing problems with proper oxygen traveling through the blood to the heart. When a piece of plaque breaks off, it can trigger a heart attack or sudden cardiac arrest.

This disease is often found in those 35 years of age or older, and can be prevented through the adoption of a heart-healthy lifestyle.

Congenital Heart Disease & Defects at Birth

While often corrected after birth, those who were born with a heart defect are often at a higher risk for a life-threatening arrhythmia which can lead to a SCA related death.

How to Prevent Sudden Cardiac Arrest

Preventing cardiac arrest related deaths can be as simple as knowing how to respond, and being prepared to do so.

Considering adding an AED to your home or workplace, and know how to use it. This the device that delivers the needed shock to an SCA victim’s heart. Time is of the essence when responding, which is why having an AED on hand is often one of the best measures of prevention.

Taking a class on hands-only CPR and encouraging others to do so as well increases the number of people willing and able to respond.

Sadly, most conditions that lead to a SCA event go undetected because of standard medical practices that do not screen for these during formative years.

Even physicals for athletic participation do not require preventative heart screenings, so life-threatening heart issues are often missed. And because the first symptom is often a cardiac arrest, there are rarely warning signs to take notice of.

RELATED: Collegiate football player dies from SCA event despite 25 pre-performance physicals.

The best way to prevent a SCA in your children or loved ones is to have their and your heart screened. Seemingly normal, healthy adolescents and adults die daily due to SCA because they did not know about the ticking time bomb inside their heart.

To find a preventative heart screening near you, check out this resource by state, provided by Parent Heart Watch.

To prevent Coronary Artery Disease, The National Heart, Lung, And Blood Institute recommends the following heart-healthy life-style:

Sources: Sudden Cardiac Arrest Association, National Heart, Lung, and Blood Institute, WebMD