Cardiac involvement in muscular dystrophy: advances in diagnosis and therapy

The term muscular dystrophy (MD) comprises various neuromuscular disorders that are characterised by progressive muscle weakness affecting certain muscle groups, which are specific for the respective genetic disorder. Muscular dystrophy type Duchenne (DMD) and type Becker (BMD) represent the most common X-linked genetic diseases: DMD is believed to affect one in 3500 male births whereas BMD is less frequent (one in 18 450 male births).w1 w2 However, due to the longer life expectancy of BMD patients, the prevalence of DMD and BMD is rather similar and at least 2.4/100 000.w1 Apart from progressive proximal skeletal muscle weakness and wasting, DMD and BMD are characterised by cardiac muscle involvement. Indeed, progressive cardiomyopathy has become a major cause of morbidity and mortality in these patients since progressive respiratory failure—the former number one cause of death—can be better managed due to advances in respiratory therapy today.w3 w4 Hence, cardiologists should be familiar with the distinctiveness of cardiac pathophysiology, the challenges and state-of-the-art methods in diagnosing cardiomyopathy, and the respective therapeutic options in patients with DMD and BMD. The specific clinical features of DMD and BMD in comparison to other forms of muscular dystrophy, such as limb girdle muscular dystrophy, have been described in detail previously.1 2 Briefly, initial symptoms in DMD start in early childhood and are characterised by difficulties in running and later climbing stairs caused by progressive weakness and wasting of the proximal skeletal muscles. Ambulation is lost in most DMD patients by the age of 12 years and only a few patients survive until the third decade of life. Respiratory failure constitutes one of the main causes of mortality in DMD patients, whereas BMD patients demonstrate a later onset and a similar, although slower, progression of the disease. BMD patients may survive until the sixth decade of life and …