By Debra Sherman

CHICAGO (Reuters) - Manufacturers of implantable heart defibrillators should focus on making them last longer as more children and young adults receive the devices to treat a genetic heart disorder, a top U.S. cardiologist said.

Dr. Barry Maron, director of the Hypertrophic Cardiomyopathy Center at the Minneapolis Heart Institute, said that recent studies have shown implantable cardioverter defibrillators, known as ICDs, can prevent sudden cardiac death in young people with hypertrophic cardiomyopathy (HCM).

One problem, Maron said in an interview this week, is that critical parts of the ICD, such as the wire leads that connect it to the heart, wear out over time. A young patient may need four or five lead changes in a lifetime, he said.

"That's a big deal," Maron said, and a factor that increases the hesitancy of some physicians to implant devices in younger patients. "There should perhaps be more focus on lead longevity," he said.

The disease -- which captured headlines when it claimed the lives of high-profile athletes such as "Pistol" Pete Maravich, Reggie Lewis and Hank Gaithers -- affects as many as 300,000 people in the United States and is the most common cause of sudden cardiac death in people under the age of 30.

HCM is marked by an abnormal thickening of the left ventricle, the heart's main pumping chamber, making it harder for the heart to pump blood, and can be fatal when it causes malignant heart rhythms.

"We've been able to develop this area with data to show that the most common cause of sudden death in young athletes and young people can be prevented with the judicious use of an implantable defibrillator," Maron said.

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