Cardiac Assessment in Duchenne and Becker Muscular Dystrophies

Song, Tae Jin; Choi, Young Chul

Abstract

BACKGROUND: Cardiac problems are common and are a major cause of death in both Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD). Early diagnosis and proper management are very important for prolonging life expectancy, improving mobility and the quality of life in dystrophinopathic patients. The object of this study was to assess the cardiac dysfunction in dystrophinopathic patients.
METHODS
We reviewed the clinical and laboratory findings of 53 male patients with DMD/BMD. The diagnosis was based on clinical criteria suggested by the European neuromuscular center, dystrophin gene analysis and immunohistochemistry of dystrophinopathic patients. We investigated 12-lead electrocardiography (EKG) findings, cardiac echocardiography findings and exon deletion analysis of dystrophin by multiplex polymerase chain reaction.
RESULTS
The mean age of 53 patients was 20.98+/-7.85 years old. On EKG findings of DMD/BMD patients, 50 patients (94.3%) revealed abnormal findings (DMD 36 [94.7%]/BMD 14 [93.3%]). Of the forty nine patients investigated by cardiac echocardiography, 25 patients (51.1%) showed abnormal echocardiographic findings (DMD 18 [51.4%]/BMD 7 [50.0%]), 18 patients (36.7%) had dilated cardiomyopathy, and 7 (14.3%) patients had cardiac symptoms (DMD 4 [11.4%] /BMD 3 [21.4%] numbers). There was no difference in the neurological disability score between normal echocardiographic finding patients and abnormal patients. On DNA analysis by multiplex PCR, the proximal exon deletion of dystrophin genes (exon 1-30) has a significant association with cardiac involvement compared to those of distal exon deletion (exon 31-60) (p=0.034).
CONCLUSIONS
Because DMD/BMD patients mostly have affected cardiac dysfunctions without clinical symptoms, early diagnosis and appropriate management of asymptomatic cardiac dysfunctions is very important.