Usefulness of heart rate variability as a predictor of sudden cardiac death in muscular dystrophies.

Sudden cardiac death, or cardiac arrest, is a major health problem, causing about 166,200 deaths each year among adults in the United States. It may be caused by almost all known heart diseases. Most cardiac arrests occur when the diseased heart begins to exhibit rapid and/or chaotic activity, such as ventricular tachycardia or fibrillation. Some are due to extreme slowing of the heart. All these events are called life-threatening arrhythmias. Arrhythmogenic cardiomyopathy is a frequent feature in several muscular dystrophies with a potential risk of cardiac sudden death. Among the measures able to predict the propensity to develop life-threatening arrhythmias, heart rate variability is an accepted non invasive measurement of cardiac autonomic modulation. The use of heart rate variability to measure the extent of changes in autonomic nervous system is an established risk stratification procedure in different diseases. In fact numerous studies have demonstrated the positive prognostic power of altered heart rate variability values to predict all-cause mortality, cardiac events, sudden cardiac death and heart transplantation. Usefulness of heart rate variability as a predictor of sudden cardiac death in muscular dystrophies has been reviewed.