Background

Duchenne muscular dystrophy is caused by mutations in the DMD gene, resulting in cardiomyopathy in all affected children by 18 years. Although cardiomyopathy is now the leading cause of mortality in these children, there is ongoing debate regarding timely diagnosis, secondary prevention, and treatment of this condition. The purpose of this study was to use exercise cardiac magnetic resonance imaging in asymptomatic young boys with Duchenne muscular dystrophy to describe their heart function and compare this with healthy controls.

Methods

We studied 11 boys with Duchenne muscular dystrophy aged 8.6 to 13.9 years and 11 healthy age- and sex-matched controls.

Results

Compared with the controls, boys with Duchenne muscular dystrophy had lower ejection fraction at rest (57% versus 63%; P = 0.004). During submaximal exercise, they reached similar peak tachycardia but increased their heart rate and cardiac output only half as much as controls (P = 0.003 and P = 0.014, respectively). End-systolic volume remained higher in boys with Duchenne muscular dystrophy both at rest and during exercise. When transthoracic echocardiography was compared with cardiac magnetic resonance imaging, 45% of the echocardiograms had suboptimal or poor views in the Duchenne muscular dystrophy group.

Conclusions

Boys with Duchenne muscular dystrophy had abnormalities in left ventricular systolic function that were exaggerated by exercise stress. Exercise cardiac magnetic resonance imaging is feasible in a select population of children with Duchenne muscular dystrophy, and it has the potential to unmask early signs of cardiomyopathy.

中文翻译：

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在没有心脏病的杜氏肌营养不良症男孩中锻炼心脏磁共振成像

背景

杜氏肌营养不良症是由DMD基因突变引起的，导致所有受影响的儿童在 18 岁时出现心肌病。虽然心肌病现在是这些儿童死亡的主要原因，但关于及时诊断、二级预防和治疗这种疾病的争论仍在继续。本研究的目的是对患有杜氏肌营养不良症的无症状年轻男孩使用运动心脏磁共振成像来描述他们的心脏功能，并将其与健康对照组进行比较。

方法

我们研究了 11 名年龄在 8.6 至 13.9 岁的杜氏肌营养不良症男孩和 11 名年龄和性别匹配的健康对照。

结果

与对照组相比，杜氏肌营养不良症男孩在休息时的射血分数较低（57% 对 63%；P  = 0.004）。在次极量运动期间，他们达到了相似的心动过速峰值，但心率和心输出量仅增加了对照组的一半（分别为P  = 0.003 和P  = 0.014）。杜氏肌营养不良症男孩在休息和运动期间的收缩末期容积仍然较高。当将经胸超声心动图与心脏磁共振成像进行比较时，杜兴肌营养不良组中 45% 的超声心动图显示次优或较差。

结论

患有杜氏肌营养不良症的男孩左心室收缩功能异常，运动压力夸大了这些功能。运动心脏磁共振成像在特定的杜氏肌营养不良儿童人群中是可行的，它有可能揭示心肌病的早期迹象。