Cardiac function tests in neuromuscular diseases

[Neurology and cardiology: points of contact]

Strokes resulting from cardiac diseases, and cardiac abnormalities associated with neuromuscular disorders are examples of the many points of contact between neurology and cardiology. Approximately 20-30% of strokes are related to cardiac diseases, including atrial fibrillation, congestive heart failure, bacterial endocarditis, rheumatic and nonrheumatic valvular diseases, acute myocardial infarction with left ventricular thrombus, and cardiomyopathies associated with muscular dystrophies, among others. Strokes can also occur in the setting of cardiac interventions such as cardiac catheterization and coronary artery bypass procedures. Treatment to prevent recurrent stroke in any of these settings depends on the underlying etiology. Whereas anticoagulation with vitamin K antagonists is proven to be superior to acetylsalicylic acid for stroke prevention in atrial fibrillation, the superiority of anticoagulants has not been conclusively established for stroke associated with congestive heart failure and is contraindicated in those with infective endocarditis. Ongoing trials are evaluating management strategies in patients with atrial level shunts due to patent foramen ovale. Cardiomyopathies and conduction abnormalities are part of the spectrum of many neuromuscular disorders including mitochondrial disorders and muscular dystrophies. Cardiologists and neurologists share responsibility for caring for patients with or at risk for cardiogenic strokes, and for screening and managing the heart disease associated with neuromuscular disorders.

The heart in muscular dystrophy

Pediatricians and other healthcare professionals need to be alert to the presence and progression of cardiac involvement in patients with MD. The signs and symptoms of cardiac involvement may be minimal, necessitating careful interval history, physical examination, and noninvasive cardiac testing. Available treatment strategies may reduce disease morbidity and mortality. It is reasonable to expect that a child who has skeletal muscle weakness from MD may have cardiac involvement, even if it is subclinical. Treatment of the muscular dystrophies through genetic engineering is a future dream. However, the improvements in clinical care, evaluation and treatment standards, and multidisciplinary supportive care are able to benefit the current generation of children.