Sat, May 12, 2012

Sudden Death in Athletes

Sudden death in athletes is most commonly caused by heart problems. Although rare in children and teenagers, several episodes happen every year across the country.

What is sudden cardiac death?

Sudden cardiac death refers to any process by which the heart suddenly stops beating. The vast majority of cases of sudden cardiac death occur in older adults who have pre-existing heart problems. For example, in older people who have had heart attacks, or myocardial infarctions, sudden cardiac death is often triggered by electrical disturbances related to the injured heart muscle.

What causes sudden death in athletes?

Sudden death in athletes is rare. Most cases are caused by heart related problems, although other causes do exist. Heat stroke, asthma, and severe dehydration are potential non-heart related causes. Heart related causes include hypertrophic cardiomyopathy, congenital coronary artery anomalies, and electrical disturbances such as long QT syndrome.

Hypertrophic cardiomyopathy (HCM) is responsible for up to 50% of cases of sudden death in athletes. HCM is a genetic abnormality in which the heart muscle is much thicker than normal. In particular, the ventricular septum, or middle wall of the heart, is thickened out of proportion to the rest of the heart. This can lead to obstruction of blood flow out of the heart during times of intense activity. Obstruction of blood flow can predispose to ischemia, or decreased blood and oxygen flow to the heart muscle. This in turn can trigger electrical disturbances leading to sudden death.

Congenital coronary artery anomalies are the second most common cause of sudden death in athletes. The most common congenital coronary artery anomaly causing sudden cardiac death is an anomalous origin of the left coronary artery from the right sinus of Valsalva. In this situation, the left coronary artery passes between the aorta and pulmonary artery. The acute takeoff of the left coronary artery, as well as possible compression between the great arteries, predisposes to ischemia and sudden death.

Finally, electrical disturbances may cause of sudden death in athletes. Long QT syndrome is a genetic disorder of cardiac ion channels. Cardiac ion channels are responsible for the exchange of electrolytes across the cardiac cell wall. In long QT syndrome, abnormalities in the cardiac ion channels create an environment where the heart is predisposed to episodes of ventricular tachycardia. This can result in sudden death.

Can sudden death in athletes be prevented?

A number of measures have been instituted to prevent sudden death in athletes. Preparticipation screening involves a thorough history and physical examination in an effort to detect potential underlying heart disorders. In the presence of suspicious findings, children and teenagers may be referred for further cardiac evaluation, including an ECG and echocardiogram. Currently mass screening of children and teenagers is not endorsed by the American Heart Association. Nevertheless many local community hospitals and clinics offer this service to young athletes.

The most effective means to prevent sudden death in athletes involves immediate resuscitation and defibrillation/cardioversion with automated external defibrillators (AED). An AED is an external device which can automatically diagnose potentially life-threatening arrhythmias and administer a life-saving electrical shock. The increasing widespread use of AED's on high school and college athletic campuses may very well prove to be the most effective way in preventing sudden death in athletes.