The largest assessment of people with adult muscular dystrophy has identified risk factors that can lead to sudden death for individuals with the most common form of this disease.
The results of the multicenter study, lead by the Indiana University School of Medicine, are reported in the June 19 issue of the New England Journal of Medicine.
Neurologists and cardiologists at 23 neuromuscular disease clinics nationwide affiliated with the Muscular Dystrophy Association assessed 406 adult patients with myotonic dystrophy type 1 using clinical history, genetic assessment and electrocardiograms (ECG) to determine the risk factors that cause arrhythmias and sudden cardiac death.
"The study has prospectively identified risk factors that predict a high risk of sudden death in people with myotonic dystrophy, the most common form of muscular dystrophy that we see in adults," said the study's principal investigator and lead author William J. Groh, M.D., M.P.H., associate professor of medicine at the Indiana University School of Medicine and the Krannert Institute of Cardiology. Sudden death is defined as a death that occurs in a stable patient within one hour of the onset of symptoms.
During the 10 years of the study, 20 percent of the people enrolled died, said Dr. Groh. Of those, one-third died of sudden death likely attributable to cardiac arrhythmia.
"Patients who had significant abnormalities on their ECG were at a 3.5 times higher risk of sudden death," said Dr. Groh. "Those with atrial (upper) chamber arrthymias had a 5 times higher risk."