Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Dr Subotica Street 6, 11 000 Belgrade, Serbia.
J Neurol Sci. 2011 Aug 15;307(1-2):30-3. doi: 10.1016/j.jns.2011.05.028. Epub 2011 Jun 11.
To evaluate cardiac autonomic control in patients with myasthenia gravis (MG) and thymoma.
The study was performed on 21 patients with MG and thymoma and the same number of matched healthy volunteers. Standard cardiovascular reflex tests according to Ewing and baroreflex sensitivity (BRS) at rest was applied. Spectral analysis of heart rate variability (HRV) at rest was assessed using a 20-minute ECG recording (normalized low- and high-frequency bands-LFnu-RRI, HFnu-RRI and LF/HF-RRI) Time-domain analysis of HRV was derived from 24-hour ECG monitoring.
Overall autonomic score according to Ewing was significantly increased in patients with MG and thymoma (p<0.05), mostly due to parasympathetic dysfunction. Time-domain parameters representing the overall and long-term sympathetic activity of HRV did not differ significantly between the two groups (p>0.05), but there was a significant decrease in measures of the short-term vagal variations in HRV (p<0.01). HFnu-RRI was lower, while LFnu-RRI and LF/HF-RRI were higher in patients with MG and thymoma in comparison to healthy controls but these differences were not of statistical significance (p>0.05). BRS at rest was highly significantly reduced in patients group (p<0.01).
Our results showed mainly parasympathetic cardiac impairment in patients with myasthenia gravis and thymoma. Since autonomic dysfunction may lead to cardiac conduction abnormalities and sudden death, the investigation of autonomic nervous system function in these patients may be significant in everyday clinical practice.
评估重症肌无力（MG）和胸腺瘤患者的心脏自主神经控制。
本研究对 21 例 MG 和胸腺瘤患者和相同数量的匹配健康志愿者进行了研究。应用 Ewing 标准心血管反射试验和自主神经反射敏感性（BRS）检测。采用 20 分钟心电图记录（LFnu-RRI、HFnu-RRI 和 LF/HF-RRI 的正常低和高频带）评估心率变异性（HRV）的频谱分析，从 24 小时心电图监测中得出 HRV 的时域分析。
MG 和胸腺瘤患者的 Ewing 整体自主神经评分显著升高（p<0.05），主要是由于副交感神经功能障碍。HRV 代表整体和长期交感神经活动的时域参数在两组之间无显著差异（p>0.05），但 HRV 短期迷走神经变化的测量值显著降低（p<0.01）。与健康对照组相比，MG 和胸腺瘤患者的 HFnu-RRI 较低，而 LFnu-RRI 和 LF/HF-RRI 较高，但这些差异无统计学意义（p>0.05）。BRS 在休息时显著降低。
我们的结果表明，MG 和胸腺瘤患者主要存在心脏副交感神经损伤。由于自主神经功能障碍可能导致心脏传导异常和猝死，因此在日常临床实践中对这些患者的自主神经系统功能进行检查可能具有重要意义。
