Cardiomyopathy in neuromuscular disorders

Many neuromuscular disorders affect more than skeletal muscle. Because of the common structural and now more apparent molecular features between skeletal and cardiac muscles, many of the neuromuscular disorders also result in cardiovascular complications. Cardiomyopathy and conduction system diseases are the most frequent extramuscular features seen with many muscular dystrophies. The most common pediatric neuromuscular diseases with cardiac involvement will be discussed, including Duchenne muscular dystrophy, the sarcoglycanopathies, the laminopathies, Friedreich ataxia and Myotonic dystrophy. Although different molecular mechanisms lead to cardiac and skeletal muscle dysfunction in each of these disorders, the primary cardiac consequences include arrhythmias and cardiomyopathy that may or may not lead to congestive heart failure. As different experimental therapies are moving into clinical trials, the effect on the cardiac aspects of disease must be considered. Similarly, as treatments for cardiomyopathy are being tested, the effects on skeletal muscle must be determined.