Genetic mutation is cause behind cardiac conduction disease
An Amsterdam emergency room finding became the first molecular insight into cardiac conduction disease that is a disorder slowing down rhythm of the heart to necessitate pacemaker implantation in millions worldwide.
The newly defined genetic mutation could be serving as a model for understanding what happens in aging hearts, according to senior author of the report Dr. Jeffrey R. Balser, associate professor of Anesthesiology and Pharmacology and holder of the James Tayloe Gwathmey Physician-Scientist Chair at Vanderbilt University.
From Sciencedaily.com:
“The heart is very sensitive to how its sodium channels work, and we suspect that aging may have subtle effects on sodium channels, not unlike the effects we see in this unusual family. We don’t know that yet, but at least we have some insight now into how sodium channel defects can produce isolated conduction disturbances.”
Balser and colleagues also made the surprising discovery that steroids inhibit the effect of the mutation. Steroids were used to treat the Dutch child before it was understood that she had a mutation-her physicians originally thought that inflammation of the heart might have been preventing normal conduction. Oddly, steroids improved her condition.
Likewise, when the investigators bathed the cultured mutant channels in steroids before studying their behavior, the functional defects disappeared.
“We theorize that steroids are inducing the production of a protein that interacts with the sodium channel and somehow cancels out the effects of the mutation,” Balser said. “We’d really like to know if there is such a protein and what it is-if we knew that, it might be possible to provide that protein, instead of pacemakers, to patients with acquired conduction disease.”
The studies were supported by the Interuniversity Cardiology Institute Netherlands, the Dutch Heart Foundation, and the National Institutes of Health.
Tags: cardiac conduction, genetic mutation, pacemaker, pacemakers, Steroids
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