Objective Heart failure is one of the most serious complications in Duchenne muscular dystrophy (DMD). Beta-blocker medication is known to improve the prognosis of chronic heart failure of adults, but its efficacy and safety for DMD patients has not been fully assessed. Thus we conducted a multicenter open trial. Methods Fifty-four DMD patients participated; 41 received carvedilol (BB group) and 13 did not (non BB group). All patients with an ejection fraction of less than 50% received angiotensin-converting enzyme inhibitor. Then, patients in BB group were started on carvedilol. The mean maintenance dose of carvedilol in BB group was 7.85±2.80 mg/day. Clinical signs and cardiac function were monitored regularly and statistical analysis was done. Results The survival rate free from primary endpoints (death, deterioration of heart failure and severe arrhythmia) was higher in the BB group. The survival rate free from all-cause death was also higher in the BB group, although not significantly higher. Patients with primary endpoints received lower maintenance doses of carvedilol and presented higher mean heart rates (HR) during the observation period. In the BB group, mean HR at enrollment and the reduction of mean HR were correlated with the change of ejection fraction. Although serious adverse events were rare during the introduction of carvedilol, patients with advanced cardiac dysfunction required a longer period for up-titration and frequently presented with minor complaints. Conclusion The present study suggests that carvedilol is relatively safe and can prevent cardiac events even in patients with DMD.

Myotonic dystrophy is an inherited systemic disorder affecting skeletal muscle and the heart. Genetic testing for myotonic dystrophy is diagnostic and identifies those at risk for cardiac complications. The 2 major genetic forms of myotonic dystrophy, type 1 and type 2, differ in genetic etiology yet share clinical features. The cardiac management of myotonic dystrophy should include surveillance for arrhythmias and left ventricular dysfunction, both of which occur in progressive manner and contribute to morbidity and mortality. To promote the development of care guidelines for myotonic dystrophy, the Myotonic Foundation solicited the input of care experts and organized the drafting of these recommendations. As a rare disorder, large scale clinical trial data to guide the management of myotonic dystrophy are largely lacking. The following recommendations represent expert consensus opinion from those with experience in the management of myotonic dystrophy, in part supported by literature‐based evidence where available.

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Objective To investigate the relationship between heart rate variability and hypercapnia. Patients and Methods

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