Relationship between Respiratory Muscle Strength and Cardiac Function in Duchenne Muscular Dystrophy

Objective: To investigate the relationship between respiratory muscle strength and cardiac function in patients with Duchenne muscular dystrophy (DMD). Method: This study included 37 patients with DMD. Cardiac function of patients was evaluated by thoracic echocardiography, which recorded left ventricular ejection fraction (LVEF). Maximal expiratory pressure (MEP) and maximal inspiratory pressure (MIP) representing respiratory muscle strength and blood sampling for brain natriuretic peptide (BNP) were performed. Results: LVEF did not show significant correlation with MIP, MEP or age. However, LVEF was negatively correlated with BNP level. Conclusion: Cardiac dysfunction of patients with DMD didn't correlate with age or respiratory muscle strength. Therefore, investigation of cardiac function itself is needed for patients with DMD irrespective of respiratory compromises.