Muscle pathology associated with cardiac function in Duchenne muscular dystrophy

This study aimed to investigate the associations between echocardiogram-based cardiac function indices and fibrosis of the abdominal and lower extremity muscles in Duchenne muscular dystrophy (DMD) and identify the indices predictive of cardiac function changes during disease progression. Twenty-one non-ambulant patients with DMD who consented to participate in the study were enrolled. The association between cardiac dysfunction and fibrosis of the abdominal and lower extremity muscles was determined by analyzing the echocardiography and elastography data for the abdominal and extremity muscles. The patients’ mean age was 18.45 ± 4.28 years. The strain ratios of the abdominal and quadriceps muscles were significantly higher than that of the medial gastrocnemius muscle (GCM). The rectus abdominis muscle showed a higher strain ratio than the biceps femoris muscle and GCM, and the quadriceps muscle showed a higher strain ratio than the GCM. The strain ratio of the rectus abdominis muscle was negatively correlated with the left ventricular ejection fraction. The degree of fibrosis of respiratory muscles was also significantly associated with cardiac dysfunction; therefore, it can be used as a predictor of cardiac dysfunction in patients with DMD in clinical practice.