Association between motor function decline and early cardiac dysfunction in ambulatory boys with Duchenne muscular dystrophy

Background Duchenne muscular dystrophy (DMD) is an X-linked recessive neuromuscular disorder caused by mutations in the dystrophin gene. It is a severe form of muscular dystrophy that is characterized by increasing muscle weakness. Heart problems may begin early in the course of the disease and may be associated with declining motor function. Aim To determine if there is a relationship between declining motor function and early cardiac dysfunction in ambulatory boys with DMD. Subjects and methods This analytic observational study consisted of 32 ambulatory boys diagnosed with genetically diagnosed DMD and who sought Neurology Clinic services at Fayoum University Hospitals. All subjects underwent clinical evaluation, including evaluation using the Motor Function Measure (MFM) scale and electrocardiogram and echocardiogram studies. Results The study revealed that the average age of the patients was 8.9 ± 1.8 years, with the average symptom duration being 4.1 ± 1.5 years. The average total Motor Function Measure was found to be 72.8 ± 13. The average left ventricular ejection fraction was found to be 58.4 ± 5.6%, whereas the average global longitudinal strain was found to be − 18.1 ± 2.3%. Mild systolic dysfunction was observed in 25% of the patients. Significant correlations were observed between total motor score and left ventricular ejection fraction ( r = 0.46, p = 0.004), total motor score, and global longitudinal strain ( r = − 0.51, p = 0.002). Conclusion It was observed that the deterioration of motor functions in ambulatory boys with DMD is associated with the early signs of cardiac dysfunction. It was found that the motor functions, if monitored by the MFM scale, would help to identify the patients at a high risk of developing cardiac dysfunction, thereby highlighting the need for early cardiological examination.