WEDNESDAY, Sept. 13 (HealthDay News) -- Young adolescent boys with a heart condition known as long-QT syndrome (LQTS) are four times more prone to cardiac arrest and sudden cardiac death than girls of similar age, a new study shows.

Reporting in the Sept. 13 issue of the Journal of the American Medical Association, a team from the University of Rochester Medical Center tracked the health of nearly 2,800 adolescents with LQTS, an abnormality of the heart's electrical rhythm.

During the study, 81 of the adolescents had an "aborted cardiac arrest" -- an abrupt loss of heart function that does not result in death because it is reversed, as with defibrillation. Forty-five experienced sudden cardiac death.

The researchers found three factors to be associated with cardiac arrest or sudden cardiac death: a recent loss of consciousness, the duration of the QTc interval (an electrocardiogram measurement), and gender.

Among the 10- to 12-year-olds, boys were four times more likely than the girls to have cardiac arrest or sudden cardiac death. Gender did not affect risk in 13- to 20-year-olds.

Adolescents who had lost consciousness once during the last two years were nearly 12 times more likely than those who had not done so for the past 10 years to have a life-threatening event, the researchers said. Losing consciousness two or more times during the last two years boosted the risk 18-fold compared with those who had not lost consciousness.

In the adolescents who had lost consciousness during the last two years, receiving beta-blocker therapy reduced their risk of life-threatening events by 64 percent.

The authors of the study concluded that identifying these risk factors "might serve as a useful guide for prophylactic treatment decisions to reduce the risk of sudden death in patients with LQTS during the high-risk teenage years."

More information

The American Heart Association has more about long-QT syndrome.