What is sudden cardiac arrest?
Sudden cardiac arrest (SCA) is a condition in which the heartbeat stops abruptly and unexpectedly. This usually is caused by ventricular fibrillation (VF), an abnormality in the heart's electrical system. When this happens, blood stops flowing to the brain the heart and the rest of the body, and the person collapses. A quick combination of CPR and defibrillation can restore life.
Is SCA the same as a heart attack?
No. A heart attack is a condition in which a blood clot suddenly blocks a coronary artery, resulting in the death of the heart muscle supplied by that artery, unless the clot is opened within a few hours. Heart attack victims usually experience symptoms such as chest discomfort or pain and remain conscious. Most people who have a heart attack survive the event. Some will develop an SCA. Other people have an SCA independently from a heart attack and without warning signs. SCA results in death if it is not treated immediately.
Who is at risk for SCA?
SCA often occurs in active people who seem to be healthy and have no known medical conditions. In these patients, SCA is the first indication of a heart condition. However, some people can be identified in advance as being at risk for SCA. Risk factors include:
- Previous heart attack
- Coronary artery disease (and risk factors for CAD including smoking, high blood pressure,
- diabetes, elevated LDL cholesterol, family history of heart disease, sedentary lifestyle)
- Heart failure from other causes
- Abnormal heart rate or rhythm (arrhythmia) of unknown cause
- Episodes of fainting of unknown cause
- Low ejection fraction (EF) (<35%)
Because sudden cardiac arrest can affect any seemingly healthy student, we recommend that parents partner with their pediatricians to evaluate their child’s need for a more detailed cardiac evaluation. Learn more about sudden cardiac arrest screening recommendations.
What causes SCA in young people?
There are three common causes.
- Long QT syndrome is an often unrecognized congenital condition that predisposes the child to an abnormality in the heart's electrical system, which can lead to SCA. This is a genetic disease that affects 1 in 7,000 young people. Episodes are most commonly triggered by physical exertion or emotional stress.
- Commotio cordis is an electrical disturbance cases by a blow to the chest. It occurs most often in baseball, but has been reported in other sports and situations in which there is a blow to the chest. Researchers at the U.S. Commotio Cordis Registry studied 124 cases and found the average age is 14. Only 18 victims (14%) survived; most who survived received prompt CPR and defibrillation.
- Hypertropic cardiomyopathy is a congenital heart muscle disease. The walls of the heart's left ventrical become abnormally thickened (hypertrophy). The structural abnormality can lead to obstruction of blood flow from the heart, causing loss of consciousness and irregular heartbeat, leading to SCA. About 1 in 500 to 1000 young people have this condition.
Source: Sudden Cardiac Arrest Foundation