Department of Clinical Medicine, Clinical Immunology Unit-Scleroderma Center, Sapienza University of Rome, Rome, Italy.
Department of Radiological, Oncological and Pathological Sciences, Sapienza University of Rome, Rome, Italy.
Int J Rheum Dis. 2019 Jun;22(6):1029-1035. doi: 10.1111/1756-185X.13569. Epub 2019 Apr 15.
Autonomic dysfunction (AD) is an early feature of systemic sclerosis (SSc). A regular endothelial function is a prerequisite for normal response of the myocardial blood flow (MBF) to cold pressure test (CPT). The aim of the study was to evaluate the relation between MBF and AD at rest and after CPT in asymptomatic SSc patients.
Twenty SSc patients and 10 age-, sex- and body mass index-matched healthy controls underwent cardiac magnetic resonance at rest and after CPT. All subjects underwent 24 hours ambulatory 3-channel electrocardiogram Holter to evaluate AD by heart rate variability.
We did not observe any significant difference in MBF (mL/g/min) at rest and after CPT between SSc patients and healthy controls. Delta of MBF (difference between MBF after CPT and rest MBF) was lower (P = 0.039) in SSc patients than healthy controls (0.28 [0.04-0.40] vs 0.33 [0.24-0.54]). The low frequency/high frequency (LF/HF) was higher (P = 0.002) in SSc patients than healthy controls (3 [1.7-6] vs 1.8 [1.1-2.8]). The high frequencies (HF), modulated mainly by paraympathetic system, was lower (P = 0.003) in SSc patients than healthy controls (30 [16-42] vs 36.5 [24-44]). Sympathetic hyperactivity, due to reduction of parasympathetic activity (HF), is present in SSc patients. A negative correlation was observed between Delta of MBF and LF/HF (r = -0.572, P = 0.0031).
AD, characterized by sympathovagal imbalance due to a reduced parasympathetic tone with high LF/HF ratio, could be responsible for the reduced myocardial vasodilatory response after CPT.
自主神经功能障碍（AD）是系统性硬化症（SSc）的早期特征。正常的内皮功能是心肌血流（MBF）对冷压力测试（CPT）正常反应的先决条件。本研究旨在评估无症状 SSc 患者静息和 CPT 后 MBF 与 AD 之间的关系。
20 例 SSc 患者和 10 例年龄、性别和体重指数匹配的健康对照者在静息和 CPT 后进行心脏磁共振检查。所有受试者均进行 24 小时动态 3 通道心电图 Holter 检查，通过心率变异性评估 AD。
我们未观察到 SSc 患者和健康对照组之间在静息和 CPT 后 MBF（mL/g/min）有任何显著差异。CPT 后 MBF 与静息 MBF 的差值（CPT 后 MBF 减去静息 MBF）在 SSc 患者中较低（P=0.039）（0.28 [0.04-0.40] vs 0.33 [0.24-0.54]）。SSc 患者的低频/高频（LF/HF）比值较高（P=0.002）（3 [1.7-6] vs 1.8 [1.1-2.8]）。HF 主要由副交感神经调制，在 SSc 患者中较低（P=0.003）（30 [16-42] vs 36.5 [24-44]）。由于副交感神经活动减少（HF），SSc 患者存在交感神经活动亢进。MBF 差值与 LF/HF 呈负相关（r=-0.572，P=0.0031）。
AD 表现为交感-副交感神经失衡，由于副交感神经张力降低导致 LF/HF 比值升高，可能是 CPT 后心肌血管舒张反应减弱的原因。
