Dhargave Pradnya, Nalini Atchayaram, Abhishekh Hulegar Ashok, Meghana Adoor, Nagarathna Raghuram, Raju Trichur R, Sathyaprabha Talakad N
National Institute of Mental Health and Neurosciences, Bangalore, India.
Bangalore Medical College and Research Institute, Bangalore, India.
Eur J Paediatr Neurol. 2014 May;18(3):317-20. doi: 10.1016/j.ejpn.2013.12.009. Epub 2014 Jan 8.
Duchenne muscular dystrophy (DMD) is a hereditary neuromuscular disorder frequently associated with progressive cardiac dysfunction, and is one of the common causes of death in these children. Early diagnostic markers of cardiac involvement might help in timely intervention. In this study we compared the short term HRV measures of DMD children with that of healthy subjects.
One hundred and twenty-four genetically confirmed boys with DMD and 50 age matched controls were recruited. Error-free, electrocardiogram was recorded in all subjects at rest in the supine position. HRV parameters were computed in time and frequency domains. Time domain measures included standard deviation of NN interval (SDNN), and root of square mean of successive NN interval (RMSSD). Frequency domain consisted of total, low frequency and high frequency power values. Ratio of low frequency and high frequency power values (LF/HF) was determined using customized software.
HRV parameters were significantly altered in DMD children as compared to healthy controls. Following parameters [mean (SD)] were reduced in DMD as compared to controls; RMSSD (in ms) [52.14 (33.2) vs 64.64 (43.2); p = 0.038], High frequency component (nu) [38.77 (14.4) vs 48.02 (17.1); p = 0.001] suggesting a loss of vagal tone. In contrast, measure of sympathovagal balance LF/HF [1.18 (0.87) vs 0.89 (0.79); p = 0.020] was increased in DMD group.
In this cross sectional study we have demonstrated alteration in autonomic tone in DMD. Loss of vagal tone and an increase in sympathetic tone were observed in DMD children. Further prospective studies are required to confirm the utility of these measures as predictors of adverse cardiac outcome in DMD.
杜氏肌营养不良症（DMD）是一种遗传性神经肌肉疾病，常伴有进行性心脏功能障碍，是这些儿童常见的死亡原因之一。心脏受累的早期诊断标志物可能有助于及时干预。在本研究中，我们比较了DMD患儿与健康受试者的短期心率变异性（HRV）指标。
招募了124名基因确诊的DMD男孩和50名年龄匹配的对照。所有受试者均在仰卧位休息时记录无误差心电图。在时域和频域计算HRV参数。时域指标包括NN间期标准差（SDNN）和连续NN间期均方根（RMSSD）。频域由总功率、低频功率和高频功率值组成。使用定制软件确定低频与高频功率值之比（LF/HF）。
与健康对照组相比，DMD患儿的HRV参数有显著改变。与对照组相比，DMD患儿的以下参数[平均值（标准差）]降低；RMSSD（单位：毫秒）[52.14（33.2）对64.64（43.2）；p = 0.038]，高频成分（nu）[38.77（14.4）对48.02（17.1）；p = 0.001]，提示迷走神经张力丧失。相比之下，DMD组交感神经与迷走神经平衡指标LF/HF[1.18（0.87）对0.89（0.79）；p = 0.020]升高。
在本横断面研究中，我们证明了DMD患儿自主神经张力的改变。观察到DMD患儿迷走神经张力丧失，交感神经张力增加。需要进一步的前瞻性研究来证实这些指标作为DMD患儿不良心脏结局预测指标的实用性。
