Invited Review Cardiomyopathy of Duchenne Muscular Dystrophy: Current Understanding and Future Directions

Duchenne muscular dystrophy (DMD) is the most common and severe form of muscular dystrophy and occurs in 1 in 3500 male births. Improved survival due to improvements in clinical care of the musculoskeletal and respiratory systems has led to an increased incidence of cardiomyopathy. Cardiac-related deaths are now seen in approximately 20% of DMD patients. Our current understanding of DMD cardiomyopathy has increased significantly over the past 10 years, but further research is required to improve cardiac treatment and outcomes in DMD. This review provides a summary of the current literature and discussion of potential new therapies for DMD cardiomyopathy. Muscle Nerve 44: 8–19, 2011 Duchenne muscular dystrophy (DMD) is the most common and severe form of muscular dystrophy and occurs in 1 in 3500 male births. Due to a mutation in the protein dystrophin, patients with DMD develop progressive muscle weakness and lose the ability to walk between 10 and 12 years of age. In the second decade of life, respiratory and cardiac muscle diseases become significant contributors to disease progression and quality of life. Improvements in the treatment of respiratory muscle disease, including assist devices and mechanical ventilation, allow patients to live longer with improved respiratory function. Eagle et al. showed that patients who undergo spinal surgery and nocturnal ventilation have a mean survival of 30 years, compared with patients who are only ventilated (22.2 years). However, this increased lifespan has allowed cardiac disease to emerge as a major cause of patient morbidity and mortality. Cardiomyopathy is now a leading cause of death in DMD patients. As this paradigm switch continues, new focus on the diagnosis and treatment of cardiac disease in DMD is essential. This review focuses on our current understanding of the diagnosis and treatment, along with potential new therapies, for the cardiomyopathy of DMD.