What Is The Risk Factor For Sudden Death in Patients With Myotonic Dystrophy?
Posted Sep 07 2008 2:15am
When we talk about muscular dystrophy (MD), we refer it to a group of more than 30 genetic diseases characterized by progressive weakness and degeneration of the skeletal muscles that control movement.
Myotonic muscular dystrophy or in short myotonic dystrophy, being the most common form of MD, will cause a person prolonged muscle spasms, cataracts, cardiac abnormalities, and endocrine disturbances. Patients with myotonic dystrophy have long, thin faces, drooping eyelids, and a swan-like neck.
Statistics showed that approximately 1 of every 8,000 people in the United States was affected by myotonic dystrophy. The heart muscle of the people with such disease is adversely affected.
Over the period of 10 years, neurologists and cardiologists at 23 clinics studied 406 adults with myotonic dystrophy. During that period, 20 percent of the patients enrolled in the study died, one-third of them in sudden death were likely due to cardiac arrhythmia.
Cardiac arrhythmia (also known as dysrhythmia) is a condition in which abnormal electrical activity occurred in the heart. The heartbeat, either regular or irregular, may become too fast or too slow. Some arrhythmias are life threatening, which can cause cardiac arrest and sudden death. Sudden death means death occurs in a stable patient within 1 hour of the onset of symptoms.
The study carried out by the Indiana University School of Medicine found that adults having myotonic dystrophy and abnormal electrocardiograms are more than 3 times more likely to die suddenly than patients who have normal ECG, while those with atrial (upper) chamber arrthymias had a 5 times higher risk.
The researchers had identified the risk factors that predict a high risk of sudden death in people with myotonic dystrophy and their findings were published in the June 19, 2008 edition of the New England Journal of Medicine.
The report also revealed that pacemakers, commonly used to treat some forms of arrhythmia, did not help these patients prevent sudden death. However, using electrophysiological studies or by surgically implanting a cardioverter-defibrillator, doctors can guard against sudden death in patients showing this risk factor.