ABSTRACT
Muscular dystrophies encompass a group of distinct genetic disorders, sharing a common feature of skeletal muscle weakness and wasting that is believed to be due to a disease process that occurs within skeletal muscle cells. The pathological hallmarks of muscular dystrophy patients include high serum levels of cytosolic muscle enzymes and, upon muscle biopsy, evidence of ongoing muscle necrosis, muscle regeneration, intersitial fibrosis and fatty replacement. The vast genetic heterogeneity of the more than 30 forms of muscular dystrophy has been realized. It has long been recognized that many muscular dystrophy patients have significant risk of developing cardiovascular disease, with a description of a patient dying from an enlarged heart in one of the earliest known papers describing muscular dystrophy patients.1 Given that there are significant similarities, both structural and functional, between cardiac and skeletal muscle, similar disease mechanisms may be involved in both skeletal muscle fibers and cardiac muscle cells. Elevations in cardiac-specific cytoplasmic markers such as cardiac troponin I in some muscular dystrophy patients may be analogous to release of creatine kinase from skeletal muscle. However, many proteins mutated in muscular dystrophy patients are also expressed in the vasculature or the cardiac conduction system, and have the potential to modify cardiovascular function in addition to any primary defect in cardiac muscle cells themselves.
