October 3, 2003

ON HEART DEGENERATION AND MUSCULAR DYSTROPHY

At the end of September, when summer finally loosened its grip on the Arizona desert here in Tucson, some 50 neuromuscular and cardiac experts and several MDA staff members undertook two days of intense exploration of an emerging problem in muscular dystrophy: heart disease. (To read a full report of this meeting, see “Conference Report” ).

When I say that heart disease is an emerging problem, I don’t mean that its existence is anything new. After all, the heart is a muscle and is affected in many forms of MD. But, until now, the cardiac aspects of this group of diseases haven’t received much attention.

Years ago, by the time the heart muscle had lost pumping power in diseases like Duchenne dystrophy, most children were almost entirely unable to move, causing their hearts little stress. At the same time, the failure of their respiratory muscles was making breathing difficult and pneumonia frequent -- and often fatal.

But times have changed, thanks to MDA’s research program and its extensive network of dedicated physicians. Assisted ventilation and mechanical aids for secretion clearance have markedly improved the respiratory function of many children with even the most severe forms of MD, allowing many to become adults, attend college and hold jobs.

Spine-straightening surgery, heel cord releases, physical therapy and, in some cases, treatment with prednisone, have allowed children with MD to remain active, some even walking, longer.

But now the heart must keep up with these advances in care.

Understanding the precise mechanisms that underlie cardiac muscle degeneration and heartbeat abnormalities in MD was much of this recent meeting’s focus. Such understanding should lead to specific treatment targets.

While we study those mechanisms, it was encouraging to learn that it seems we can use the same drugs and electronic devices that treat cardiac disease in the general population when we treat it in MD.

Drugs called angiotensin-converting enzyme (ACE) inhibitors and others known as beta blockers, given early and in a systematic way, can save lives in MD and improve their quality. So can electronic pacemakers and implantable defibrillators. Some people with MD have even undergone successful heart transplants.

In the future, specific repair procedures using cardiac stem cells and gene transfer strategies, as well as new biochemical approaches, may bring about a true reversal of the degenerative process in the heart.

There’s much work to be done, to be sure, and this meeting will, we hope, foster many collaborations between basic scientists and clinicians, and among different laboratories across the country and around the world.

With every best wish...

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