What is SCA

SUDDEN CARDIAC ARREST (SCA) IS NOT THE SAME AS A HEART ATTACK

Sudden cardiac arrest (SCA) is a condition in which the heart suddenly and unexpectedly stops beating. When this happens, blood stops flowing to the brain and other vital organs. SCA usually causes death if it’s not treated within minutes. It is not the same as a heart attack, which is a plumbing problem that can lead to SCA, which is an electrical problem.SCA is a leading cause of death among physically active young adults.

What is the difference between
Sudden Cardiac Arrest and Heart Attack?

Sudden Cardiac Arrest (SCA)

Heart Attack (Myocardial Infarction)

Primary Problem

Electrical malfunction—the heart suddenly stops beating effectively due to a malignant arrhythmia (e.g., ventricular fibrillation or tachycardia).

Circulatory problem—a blockage in a coronary artery stops blood flow to part of the heart muscle.

Result

Abrupt loss of heart function, collapse, and death within minutes if not treated.

Myocardial ischemia and tissue damage; may cause chest pain, but not always immediate collapse.

Onset

Sudden, often without warning.

May have preceding symptoms such as chest pain or shortness of breath.

Typical Causes
in Athletes

<35 years: inherited or congenital heart conditions (e.g., hypertrophic cardiomyopathy, arrhythmogenic cardiomyopathy, long QT, Brugada, coronary anomalies). 
>35 years: coronary artery disease or demand ischemia.

Atherosclerotic plaque rupture and thrombosis causing blockage of a coronary artery.

Relationship Between the Two

SCA can occur with or without a heart attack; often due to electrical or structural heart disease.

A heart attack can lead to SCA if it triggers a fatal arrhythmia, but most do not.

Type of Event

Electrical—disruption of rhythm and cardiac output.

Vascular—interruption of blood flow causing muscle injury.

What causes Sudden Cardiac Arrest in Athletes?

  • Young athletes: inherited electrical or structural heart diseases (arrhythmia syndromes, cardiomyopathies, coronary anomalies).
  • Older athletes: acquired coronary artery disease.
  • Some cases remain unexplained even after autopsy, suggesting undiagnosed electrical (ion channel) disorders.

What are current Screening Strategies for SCA in Athletes?

  • U.S.: History and physical are the foundation; ECG only if indicated.
  • Europe: Routine ECG for competitive athletes.
  • Key principle: Use expert, athlete-specific interpretation to minimize false positives and maximize early detection.

How does SCA compare among military athletes vs. professional athletes?

SCA in the military is more common than in young athletes, often linked to early atherosclerotic disease, and shows better survival outcomes thanks to rapid recognition, bystander CPR, and early defibrillation.

  • SCA occurs more frequently in military personnel than in athletes, but less frequently than in the general population.
  • Survival is far higher in the military due to a controlled environment with immediate emergency response—mirroring best practices in well-prepared athletic venues.
  • Etiology shifts with age: congenital/inherited causes dominate in younger athletes, while atherosclerotic disease is predominant in older service members and civilians.
  • Both groups highlight the importance of emergency preparedness (AEDs + trained responders) and targeted screening to reduce SCA deaths.

Did you know…

  • SCA is the leading cause of non-traumatic death in military populations and specifically among recruits in training.
  • Over half of those who suffer SCA have no prior symptoms.
  • When someone suffers SCA, only a shock from an Automated External Defibrillator (AED) within 3 to 5 minutes will revive them.
  • For every minute of delay, the chance of survival drops by 10%.
  • CPR is an essential life-saving procedure that buys some time until the AED can get there.
  • Time is of the essence!
  • SCA can happen to anyone of any age and is linked to Sudden Infant Death Syndrome (SIDS).