DMD Research: Doubts About EKGs

The widely used test may not screen reliably for heart problems in DMD

by Quest Staff on April 12, 2009 - 9:00pm

Kid getting EKG
An electrocardiogram (EKG) transmits information about heart rhythms, in the form of electrical signals, to a computer. Researchers warn that the test “should not serve as a basis for decisions regarding treatment” in people with DMD.

Electrocardiograms, or EKGs, have long been used to screen children and young men with Duchenne muscular dystrophy (DMD) for the heart-muscle deterioration (cardiomyopathy) often seen in this disease. Children with DMD who have abnormalities on an EKG are generally referred for further cardiac evaluation, usually including a cardiac imaging study called an echocardiogram.

But, according to new MDA-supported research conducted at Nationwide Children's Hospital in Columbus, the EKG, which measures electrical activity in the heart, may not be a reliable screening tool for cardiomyopathy.

When the researchers administered an EKG and echocardiogram to 115 DMD patients at Nationwide who were between 3 and 27 years old, they found there were no differences in the EKGs of the 40 in whom cardiomyopathy was found by echocardiogram and the 75 in whom it was not found.

The research team, which published its findings Jan. 15, 2009, in the American Journal of Cardiology, included neurologist Jerry Mendell, co-director of the MDA clinic at Nationwide and a longtime MDA research grantee; pediatric cardiologist Hugh Allen at the same institution, whose work helped develop the field of echocardiography and who has a special interest in the effects of muscular dystrophy on the heart; Philip Thrush, resident in Pediatrics at Nationwide; and Laurence Viollet, at Nationwide's Center for Gene Therapy.

Kid getting echocardiogram
An echocardiogram transmits sound waves to a computer, where they’re converted to an actual image of the beating heart. In DMD, this test, or an MRI (magnetic resonance imaging), may be more accurate than an EKG at picking up heart-muscle deterioration.

They concluded that the EKG, while revealing abnormalities in heart rhythm typical of DMD, "should not serve as a basis for decisions regarding treatment."

Heart
For more about the effects of DMD on the heart, see Let the Beat Go On (Quest, March-April 2006).

They say echocardiography is a better way to diagnose cardiomyopathy in this disease, although they also note that it may be technically difficult and subject to varying interpretations. They suggest magnetic resonance imaging (MRI) of the heart may offer the most accurate assessment of cardiomyopathy in DMD but note that it's costly and requires sedation of young patients.

   
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