Cardiovascular Complications of Neuromuscular Disorders

In the past decade, advances in molecular genetics have shown that many familial neuromuscular and cardiovascular diseases share a common pathophysiology. They are caused by inherited mutations in the cellular cytoskeleton of cardiac and skeletal muscle cells. The clinical manifestation of cardiac disease in neuromuscular disorders is common and their management should include both periodic cardiac assessment and appropriate symptomatic and definitive therapy. Dilated cardiomyopathy is a common complication of neuromuscular diseases. Cardiac function may decline progressively as part of the natural history of the disease, but current medical therapy, including angiotensin-converting enzyme inhibitors, beta-blockers, and diuretics, can be used to alleviate symptoms of left ventricular dysfunction. Conduction disturbances may be an important cause of mortality, especially in patients with Emery Dreifuss muscular dystrophy, Kearns-Sayre syndrome, and myotonic dystrophy, and thus pacemaker implantation can be life-saving. Rhythm disturbances, such as atrial fibrillation and ventricular tachyarrhythmias, have been reported in patients with neuromuscular diseases. Treatment is based on preventing sudden death and embolic phenomena and cardioverting or controlling atrial fibrillation. In these patients, problems may arise with anticoagulation and antiarrhythmic therapy due to the inherent locomotor instability associated with the disease, and the presence of concomitant atrioventricular disease. Although uncommon, hypertrophic cardiomyopathy may be a feature of some neuromuscular disorders. Patients should undergo regular risk stratification for sudden cardiac death and symptoms such as heart failure can be treated with medical therapy.