A young, college basketball player was rumored to be a potential top pick in the professional basketball draft. Yet, during a game midseason, he experienced arrhythmias (irregular rhythms of the heart's beating). He was removed immediately from the game and was treated. Three months later, during a tournament game, he collapsed and died. The cause of death? Sudden cardiac arrest. Other athletes, professionals and amateurs, have taken to the field only to meet a fatal defeat. Statistics show that this condition is rare, but what is sudden cardiac arrest? And why has it taken the lives of such strong, healthy athletes?

What Is Sudden Cardiac Arrest?

Sudden cardiac arrest in its simplest terms means an abrupt cessation of the blood flow. "It's the abrupt loss of the heart's ability to pump blood," says Robert J. Myerburg, MD, director of the division of cardiology and a professor of medicine and physiology at the University of Miami in Florida.

Although there is usually no forewarning of a problem, symptoms can be missed or ignored, says John C. McMahon, PhD, a cardiovascular physiologist at the University of Texas in Houston. Symptoms might include fainting spells, chest pain, or shortness of breath.

Sudden cardiac arrest is not synonymous with a heart attack, Myerburg says. In a heart attack, the loss of blood supply causes heart muscle tissue to die. With sudden cardiac arrest, however, the body's electrical system becomes defective and the heart is not able to form an organized beat and is plunged into rapid or chaotic activity.

What Causes Sudden Cardiac Arrest?

One of the largest studies of sudden cardiac arrest appeared in the Journal of the American Medical Association (JAMA). In the study, researchers examined 158 sudden deaths that had occurred in trained athletes throughout the United States between 1985 and 1995.

More than half of the athletes competed at the high school level, 22% competed at the collegiate level, and 7% were professional athletes. Basketball and football accounted for the largest percentage of sports. Other sports included track, soccer, baseball, swimming, volleyball, ice hockey, boxing, crew, ice skating, tennis, and wrestling.

Of those 158 athletes, 134 suffered from cardiovascular causes of sudden death. The most common cause was hypertrophic cardiomyopathy (an inherited condition that causes the left ventricle to be abnormally thick). Other causes of sudden cardiac death in this study included coronary artery abnormalities and myocarditis, an inflammation of the heart's muscular wall. Researchers reported that about 90% of the athletes collapsed during or immediately after a training session, indicating that physical exertion appeared to trigger sudden death.

Sudden cardiac arrest may also be caused by other conditions, such as:.

• Aortic stenosis (narrowing of the aortic valve)
• Inherited (congenital) heart disease

Small Risk

Fortunately, sudden cardiac arrest in young, fit athletes is rare. "Only a small percentage of sudden death cases occurs in what appears to be overly healthy people who don't have any evidence of heart problems," says Arthur Moss, MD, professor of medicine (cardiology) at the University of Rochester Medical Center in Rochester, NY.

Can Anything Be Done to Prevent Sudden Cardiac Arrest?

The American Heart Association (AHA) recommends that young athletes are screened before participation in sports to determine their risk for sudden cardiac arrest. During the screening, the doctor will ask questions about whether the young person has a:

• Personal history of chest pain or discomfort, fainting, heart murmur, high blood pressure
• Family member who has died for heart disease at an early age
• Family history of heart conditions, like cardiomyopathy

Also during the physical exam, the doctor will listen to the heart to check for a murmur and take the pulse rate and blood pressure reading, as well as look for other signs (like fainting or shortness of breath). In addition to these preparticipation screenings, Moss adds that schools, colleges, and professional teams should have personnel trained in CPR and have a defibrillator nearby in case of an emergency.