Adults with the most common form of muscular dystrophy who have abnormal electrocardiograms are more than three times more likely to suddenly die than patients whose ECGS are normal, research showed Wednesday.
"Patients who had significant abnormalities on their ECG were at a 3.5 times higher risk of sudden death," said William Groh, lead author of research appearing in the June 19 edition of the New England Journal of Medicine.
"Those with atrial (upper) chamber arrthymias had a five times higher risk," said Groh, a professor at the Indiana University School of Medicine.
Over ten years, neurologists and cardiologists at 23 clinics assessed 406 adults with myotonic dystrophy, the most common form of the muscular dystrophy -- a group of genetic, hereditary diseases that cause progressive muscle weakness and wasting.
During that time 20 percent of the patients enrolled in the study died, one-third of them in sudden death likely attributable to cardiac arrhythmia, Groh said.
Sudden death was defined as death occurring in a stable patient within one hour of the onset of symptoms.
"The study has prospectively identified risk factors that predict a high risk of sudden death in people with myotonic dystrophy," Groh said.
Physicians can guard against sudden death in patients presenting this risk factor using electrophysiological studies or by surgically implanting a cardioverter-defibrillator, Groh said.
The research revealed that pacemakers, commonly used to treat some forms of arrhythmia, did not help these patients prevent sudden death, Groh said.
Myotonic muscular dystrophy affects approximately one of every 8,000 people in the United States. The heart muscle is adversely affected in many muscular dystrophies.