You may have heard about young athletes, still teenagers, whose hearts stop beating, sometimes while playing sports. In many of these cases, their parents and doctors find out after the fact that these young athletes have a heart condition.  But for those with a specific genetic disease, implantable defibrillators may save their lives.  Here is VOA's Carol Pearson.

It is a tragic story.  A young athlete has a heart attack and dies. 

Brandon Williams

Since then, the school Brandon attended has acquired an external defibrillator, a device that can shock a heart back into a normal rhythm. But the solution for some people is a miniature, implantable defibrillator.

Twenty-two-year-old Paul McSweeney was only 11 when doctors diagnosed him with a genetic heart disease called hypertrophic cardiomyopathy. It causes the heart wall to thicken.

Dr. Barry Maron examines Paul McSweeney

To reduce that risk, Paul had a defibrillator implanted in his chest. Later, when he took a nap after the stress of studying for final exams, his heart started beating irregularly. "I just abruptly woke up and I wasn't really sure what had happened at that point in time, and I later went in for a medical check up and they confirmed the fact that I had been defibrillated," he recalls.

His mother adds, "The timing was amazing.  He got a defibrillator only months before he needed it and it saved his life."

Dr. Barry Maron is an expert hypertrophic cardiomyopathy.  He and his colleagues studied about 500 patients like Paul with implanted defibrillators.  "We have found that it is now possible to change the natural course of the disease for some patients by preventing sudden cardiac death," said Dr. Maron.

The study was published in the Journal of the American Medical Association.

During the course of the study, the defibrillators sent electric shocks to more than 100 patients who had irregular heartbeats, saving their lives.