The Importance of Early Diagnosis and Treatment to Limit the Impact of Dystrophic Cardiomyopathy-We've Seen This Film Before, and We Didn't Like the Ending.

Duchenne muscular dystrophy (DMD) is a rare neuromuscular disorder that is characterized by skeletal muscle wasting, loss of ambulation, and respiratory failure. In addition to these obvious external signs of disease, heart disease, the leading cause of death in DMD patients, is also progressing. Dystrophic cardiomyopathy is largely clinically silent with cardiac dysfunction masked by concurrent loss of skeletal muscle function. In older DMD patients the prevalence of heart disease is very high, offering the unique potential to predict impending heart disease from a much earlier genetic diagnosis. Randomized clinical trial data and subsequent retrospective studies in DMD demonstrate that early initiation of cardiac directed therapy results in a significant delay in the onset of cardiac dysfunction and prolonged survival. Clinical guidelines reflect this, recommending the initiation of cardiac therapy at an age of 10 years old, even in the absence of documented contractile dysfunction. Despite this data, a recent examination of registry data reveals that most DMD patients are not receiving the treatments recommended by these guidelines. While there is great excitement regarding newly developed therapies for DMD, there are so many signs that deploying the safe and effective therapies we already have can improve clinical outcomes. This review will highlight the basic science behind and clinical importance of using early cardiac directed therapy to extend the duration and quality of life of DMD patients and will offer some suggestions that may aid in achieving this goal.