摄食行为对小型猪心脏自主神经功能的影响

目的观察摄食行为对小型猪心脏自主神经功能的影响。方法利用大动物无创遥测技术观察清醒活动状态下小型猪摄食前（BI）、摄食过程中（IP）、摄食后（AI）、AI 2 h和AI 4h的心电图（ECG）和自主活动,并用HRV功率谱分析其自主神经功能。结果与摄食前比较,小型猪摄食过程中心率（HR）、自主活动和标准化低频成分（LFnu）明显增加,RR间期（RRI）、总功率（TP）、极低频成分（VLF）、高频成分（HF）明显减少,LF/HF比值明显升高;且随着摄食后恢复时间的延长,小型猪HR、自主活动、LFnu均有所降低,而RRI、TP、VLF、HF均有所升高,LF/HF比值逐渐降低,并在摄食后2 h、4 h时变化显著;相关分析显示摄食行为与TP、VLF、HF、LF和LF/HF密切相关,多元线性逐步回归分析亦显示摄食行为与VLF、LF/HF和TP密切相关,且VLF起主要作用。结论小型猪摄食行为不仅影响心脏活动;而且能引起小型猪心脏自主神经控制能力发生改变,其中VLF在摄食行为过程中占有重要作用。     

2型糖尿病患者心率变异性时域及频域参数与颈动脉粥样硬化的相关性分析

摘要 目的：探讨2型糖尿病患者心率变异性（HRV）时域及频域参数与颈动脉粥样硬化（CAS）患病风险的相关性。方法：根据纳入与排除标准共收集2019年7月至2021年8月上海交通大学医学院附属第九人民医院内分泌代谢科住院的377例2型糖尿病患者的临床资料,并通过3分钟的心电图记录HRV时域[R-R间隔的标准差（SDNN）、相邻R-R间隔差值的均方根（RMSSD）、相邻R-R间隔差值>50 ms的数目占所有R-R间隔总数百分比（PNN50）]和频域[低频功率（LF）、高频功率（HF）、LF/HF、总功率（TP）]参数。根据颈动脉超声有无斑块形成分为无CAS组和CAS组,分析其与HRV各参数的关系。结果：与无CAS组相比,CAS组年龄、心血管疾病、体质量指数（BMI）、糖化血红蛋白A1c（HbA1C）、甘油三酯（TG）水平明显升高,舒张压（DBP）、空腹血糖（FPG）水平降低,差异具有统计学意义（P＜0.05）。CAS组大多数HRV参数低于无CAS组,包括SDNN、RMSSD、PNN50、LF、LF/HF、TP,差异有统计学意义（P＜0.05或P＜0.01）。SDNN与年龄、病程、心血管疾病、饮酒呈负相关（P＜0.05或P＜0.01）;RMSSD与病程、饮酒呈负相关（P＜0.05或P＜0.01）;PNN50与病程呈负相关（P＜0.05）;LF与年龄、病程、心血管疾病呈负相关,与DBP、低密度脂蛋白（LDL）呈正相关（P＜0.05或P＜0.01）;HF与年龄、病程呈负相关,与LDL呈正相关（P＜0.05或P＜0.01）;LF/HF与年龄、心血管疾病、TG呈负相关（P＜0.05或P＜0.01）;TP与年龄、病程、心血管疾病呈负相关,与DBP、LDL呈正相关（P＜0.05或P＜0.01）。使用多因素logistic回归对部分可能的混杂因素进行校正后,SDNN、RMSSD、LF、LF/HF、TP降低仍然与CAS发生的风险增加相关（均P＜0.05）。进一步按糖化血红蛋白（≤7.0%、＞7.0%）分层后分析,糖化血红蛋白＞7.0%组的患者SDNN、RMSSD、LF、TP的降低与CAS发生的风险增加相关（P＜0.05）,而在糖化血红蛋白≤7.0%组,仅RMSSD、PNN50有统计学意义（P＜0.05）。结论：2型糖尿病患者HRV参数SDNN、RMSSD、LF、TP降低与CAS发生的风险增加有关,且糖化血红蛋白＞7.0%的患者有更多的HRV参数（SDNN、RMSSD、LF、TP）与CAS相关。     

清醒高血压大鼠心率变异分析的动物模型建立

目的：研究两种不同血浆肾素水平高血压大鼠心率变异的变化,进而探讨肾素。血管紧张素系统（RAS）影响心率变异（HRV）的机制。方法：制备两种高血压大鼠模型,采集其连续心电图数据。分析HRV的变化。并测定血浆血管紧张素Ⅱ（AngⅡ）的浓度。结果：肾性高血压大鼠血浆AngⅡ明显升高（P〈0．01）,心率变异频域指标中TP（总功率谱）、VLF（极低频功率）、LF（低频功率）和HF（高频功率）明显降低,LF／HF（低高频比）升高;DOCA-盐型高血压大鼠血浆AngⅡ水平明显降低,TP、VLF、LF和HF也明显降低。LF／HF比值升高。结论：两种不同血浆肾素水平的高血压大鼠交感和迷走神经均受损,同时交感神经活性相对占优势;提示肾素血管紧张素系统是通过脑内RAS的激活而影响HRV,不是循环RAS的外周作用。     

高血压病不同级别心功不全的自主神经功能变化及相关性研究

目的通过动态心电监护下心率变异性(HRV)分析自主神经功能对高血压病不同级别心功能不全的HRV变化。方法应用动态心电图和无创性心功能测定高血压病不同级别心功能不全的心率变异性的结果进行比较。结果发现高血压病不同级别心功能不全的患者随心功能损害的加重心率变异时域参数SDNN、SDRNN、RMSSD、PNN50和频域参数TP、VLF、LF、HF、LF/HF均明显降低,且有统计学差异。结论自主神经功能损害在高血压病不同级别的心功能不全患者起着重要的作用。     

急性心肌梗死患者PCI治疗后抑郁对心率变异性、内皮功能及不良心血管事件发生率的影响

目的:探讨急性心肌梗死(AMI)患者经皮冠状动脉介入(PCI)治疗后抑郁对心率变异性(HRV)、内皮功能及不良心血管事件(MACE)发生率的影响。方法:选择2017年1月-2018年12月期间在本院接受PCI治疗的AMI患者117例作为研究对象,根据PCI术后出院当日的抑郁自评量表(SDS)评分值将其分为抑郁组(评分值≥53分)41例、非抑郁组(评分值<53分)76例。对比两组患者HRV相关指标[正常RR间期标准差(SDNN)、5 min内正常RR间期平均值标准差(SDANN)、相邻正常RR间期差值均方的平方根(RMSSD)、总功率(TP)、低频功率(LF)、高频功率(HF)、低频功率与高频功率比值(LF/HF)]、内皮功能指标[内皮依赖性血管舒张功能(FMD)、非内皮依赖性血管舒张功能(NMD)]水平差异,记录两组随访期内MACE发生情况。结果:PCI术后出院当日,抑郁组患者的HRV时域指标SDNN、SDANN、RMSSD水平低于非抑郁组患者;频域指标中LF、LF/HF的水平高于非抑郁组,HF的水平低于非抑郁组(P<0.05),两组患者TP水平的差异无统计学意义(P>0.05)。抑郁组患者的FMD、NMD水平均低于非抑郁组患者,差异有统计学意义(P<0.05)。随访期内,抑郁组患者的MACE总发生率、再发心肌梗死发生率高于非抑郁组,差异有统计学意义(P<0.05)。两组患者顽固性心绞痛、新发心肌梗死、心力衰竭、心源性死亡发生率的差异无统计学意义(P>0.05)。结论:AMI患者PCI后合并抑郁可能对心血管系统造成负面影响并最终增加MACE的发生风险。     

无创遥测技术观察运输应激对Beagle犬部分生理指标的影响

目的应用无创遥测技术观察运输应激对Beagle犬部分生理指标的影响。方法 16只Beagle犬随机分成两组（每组8只）,即对照组和运输应激组,并利用大动物无创生理信号遥测技术,分别监测清醒自由活动状态下对照组和运输应激组应激4 h后Beagle犬的心电图、活动、皮肤温度和呼吸参数的变化。结果 Beagle犬心率、RR间期、QT间期、活动、皮肤温度、呼吸均具有明显的昼夜节律变化（P〈0.01）;与对照组比,运输应激后Beagle犬心率、活动度、呼吸频率、每分钟通气量和潮气量均显著增加（P〈0.01）,RR间期、PR间期、皮肤温度均显著降低（P〈0.01）,相关分析表明运输应激对Beagle犬心率、活动、皮肤温度和呼吸频率具有显著的相关性（P〈0.05,P〈0.01）。结论运输应激可引起Beagle犬生理学指标的明显改变,但除皮肤温度外,运输应激（4 h）对Beagle犬昼夜节律变化破坏不明显;利用无创遥测技术平台可建立理想的Beagle犬生物模型,可用于动物福利和药理毒理学评价研究。     

冠心病患者动态心电图参数与血清YKL-40、LTBP-2水平的关系研究

摘要 目的：探讨冠心病患者动态心电图参数与血清甲壳质酶蛋白40（YKL-40）、潜在转化生长因子结合蛋白2（LTBP-2）水平的关系。方法：选取本院2020年3月至2023年4月154例冠心病患者纳入冠心病组（其中单支病变38例,双支病变57例,多支病变59例;Gensini积分评估冠状动脉狭窄程度包括轻度42例,中度60例,重度52例）,另选择于本院进行健康体检者90例纳入对照组,所有纳入对象均接受动态心电图检查,并检测血清YKL-40、LTBP-2水平,分析冠心病患者动态心电图参数与血清指标的关系。结果：冠心病组24 h内全部正常心动周期的标准差（SDNN）、每5 min正常R-R间期标准差（SDANN）、相邻正常心动周期差值均方根（RMSSD）、相邻2个正常心动周期差值＞50 ms个数百分比（PNN50）水平低于对照组,低频与高频功率之比（LF/HF）水平高于对照组（P＜0.05）;不同冠脉病变狭窄范围患者SDNN、SDANN、RMSSD、PNN50水平比较,多支病变＜双支病变＜单支病变,LF/HF水平比较,多支病变＞双支病变＞单支病变（P＜0.05）;不同冠脉病变狭窄程度患者SDNN、SDANN、RMSSD、PNN50水平比较,重度＜中度＜轻度,LF/HF水平比较,重度＞中度＞轻度（P＜0.05）;冠心病组血清YKL-40、LTBP-2水平高于对照组,且多支病变＞双支病变＞单支病变（P＜0.05）;不同冠脉病变狭窄程度患者血清YKL-40、LTBP-2水平比较,重度＞中度＞轻度（P＜0.05）;冠心病患者动态心电图参数SDNN、SDANN、RMSSD、PNN50水平与血清YKL-40、LTBP-2水平呈现负相关,LF/HF水平与血清YKL-40、LTBP-2水平呈现正相关（P＜0.05）。结论：冠心病患者血清YKL-40、LTBP-2呈高表达,且其表达水平随冠脉病变狭窄范围和严重程度增加而升高,与动态心电图指标SDNN、SDANN、RMSSD、PNN50水平呈现负相关,与LF/HF水平呈现正相关。     

川崎病患儿的心率变异性指标与血清NT-proBNP及cTnI水平的相关性

目的:研究川崎病患儿的心率变异性指标与血清氨基末端脑钠肽前体(NT-pro BNP)及肌钙蛋白I(cTnI)水平的相关性,为临床诊疗提供依据。方法:选取2013年7月到2015年7月我院收治的川崎病患儿120例为研究组,根据患者是否存在冠状动脉损害分为A组(有冠状动脉损害)60例和B组(无冠状动脉损害)60例,同时选取同期健康体检儿童60例为对照组,比较各组窦性N-N间期标准差(SDNN)、5min N-N间期平均值标准差(SDANN)、极低频功率(VLF)、低频功率(LF)、高频功率(HF)、NT-proBNP水平以及cTnI水平。结果:研究组SDNN、SDANN、VLF、LF以及HF显著低于对照组,且A组显著低于B组,差异具有统计学意义(P0.05);研究组NT-proBNP水平和cTnI水平显著高于对照组,且A组显著高于B组,差异具有统计学意义(P0.05);研究组NT-proBNP与SDNN和HF呈负相关关系(P0.05),cTnI与SDNN和HF呈负相关关系(P0.05)。结论:心率变异性指标与川崎病患儿冠状动脉损害有关,与NT-proBNP、cTnI呈负相关关系。     

迷走神经在心率变异性中的作用

采用功率谱和近似熵 (approximateentropy ,ApEn)的方法 ,分析清醒家兔在双侧迷走神经保留 ,右、左侧迷走神经切断以及双侧迷走神经同时切断时心搏间期 (RRI)的变化。结果显示 :双侧迷走神经保留时功率谱中高频功率 (HF)、低频功率 (LF)及ApEn值均高于双侧及单侧迷走神经切断时 (P <0 0 5 ) ,LF/HF比值最小 ;切断单侧迷走神经 ,ApEn变小 ,LF/HF比值在右侧迷走神经切断时增大 ,而切断左侧迷走时LF/HF比值无明显变化 ;双侧迷走神经切断后LF/HF比值最大 ,ApEn最低。结果表明 :心率变异主要由迷走神经调节 ,右侧迷走神经起主要作用 ;传统心率变异性测量方法与非线性方法所得结果一致     

血管紧张素Ⅱ对家兔心率变异的影响

目的:研究血管紧张Ⅱ(AngⅡ)对家兔心率变异(HRV)影响的机制。方法:分别给家兔静脉输注生理盐水,AngⅡ,溴化六烃季胺(HEXB),HEXB+AngⅡ检测安静状态下连续5 min的心电图并进行HRV的时域和频域分析。结果:血管紧张素Ⅱ组的时域指标SDNN和RMSSD较对照组明显降低,频域指标低频(LF)升高,而高频(HF)和总功率(TP)明显降低;HEXB+AngⅡ组与HEXB组相比无明显区别。结论:交感神经阻断剂HEXB不能影响AngⅡ的作用,AngⅡ主要通过抑制中枢自主神经的传出,降低迷走神经张力来降低HRV。     

Effects of psychological stress on autonomic control of heart in rats.

The aim of this study was to examine the effects of psychological stress on autonomic control of the heart in rats. For this purpose, we evoked anxiety-like or fear-like states in rats by means of classical conditioning and examined changes in autonomic nervous activity using an implanted telemetry system and power spectral analysis of heart rate variability. Anxiety-like states resulted in a significant increase in heart rate (HR), low frequency (LF) power, and LF/HF ratio, with no change in high frequency (HF) power. Fear-like states resulted in a significant increase in HR and a significant decrease in HF power with no significant change in both LF power and LF/HF ratio, although LF/HF ratio increased slightly. These results suggest that autonomic balance becomes predominant in sympathetic nervous activity in both anxiety-like and fear-like states. These changes in rats correspond to changes which are relevant to cardiovascular diseases in humans under many kinds of psychological stress. Therefore, the experimental design of this study is a useful experimental model for investigating the effects of psychological stress on autonomic control of the heart in humans.     

Sleep-related sympathovagal imbalance in SHR

The role of the autonomic nervous system in spontaneous hypertension during each stage of the sleep-wake cycle remains unclear. The present study attempted to evaluate the differences in cardiac autonomic modulations among spontaneously hypertensive rats (SHR), normotensive Wistar-Kyoto rats (WKY), and Sprague-Dawley rats (SD) across sleep-wake cycles. Continuous power spectral analysis of electroencephalogram, electromyogram, and heart rate variability was performed in unanesthetized free moving rats during daytime sleep. Frequency-domain analysis of the stationary R-R intervals (RR) was performed to quantify the high-frequency power (HF), low-frequency power (LF)-to-HF ratio (LF/HF), and normalized LF (LF%) of heart rate variability. WKY and SD had similar mean arterial pressure, which is significantly lower than that of SHR during active waking, quiet sleep, and paradoxical sleep. Compared with WKY and SD, SHR had lower HF but similar RR, LF/HF, and LF% during active waking. During quiet sleep, SHR developed higher LF/HF and LF% in addition to lower HF. SHR ultimately exhibited significantly lower RR accompanied with higher LF/HF and LF% and lower HF during paradoxical sleep compared with WKY. We concluded that significant cardiac sympathovagal imbalance with an increased sympathetic modulation occurred in SHR during sleep, although it was less evident during waking.     

Respiratory-related heart rate variability in progressive experimental heart failure

Heart failure is associated with autonomic imbalance, and this can be evaluated by a spectral analysis of heart rate variability. However, the time course of low-frequency (LF) and high-frequency (HF) heart rate variability changes, and their functional correlates during progression of the disease are not exactly known. Progressive heart failure was induced in 16 beagle dogs over a 7-wk period by rapid ventricular pacing. Spectral analysis of heart rate variability and respiration, echocardiography, hemodynamic measurements, plasma atrial natriuretic factor, and norepinephrine was obtained at baseline and every week, 30 min after pacing interruption. Progressive heart failure increased heart rate (from 91 +/- 4 to 136 +/- 5 beats/min; P < 0.001) and decreased absolute and normalized (percentage of total power) HF variability from week 1 and 2, respectively (P < 0.01). Absolute LF variability did not change during the study until it disappeared in two dogs at week 7 (P < 0.05). Normalized LF variability increased in moderate heart failure (P < 0.01), leading to an increased LF-to-HF ratio (P < 0.05), but decreased in severe heart failure (P < 0.044; week 7 vs. week 5). Stepwise regression analysis revealed that among heart rate variables, absolute HF variability was closely associated with wedge pressure, right atrial and pulmonary arterial pressure, left ventricular ejection fraction and volume, ratio of maximal velocity of early (E) and atrial (A) mitral flow waves, left atrial diameter, plasma norepinephrine, and atrial natriuretic peptide (0.45 < r < 0.65, all P < 0.001). In tachycardia-induced heart failure, absolute HF heart rate variability is a more reliable indicator of cardiac dysfunction and neurohumoral activation than LF heart rate variability.     

Power spectral analysis of heart rate variability for assessment of diurnal variation of autonomic nervous activity in guinea pigs.

We established characteristics of power spectral analysis of heart rate variability, and assessed the diurnal variations of autonomic nervous function in guinea pigs. For this purpose, an electrocardiogram (ECG) was recorded for 24 hr from conscious and unrestrained guinea pigs using a telemetry system. There were two major spectral components, at low frequency (LF) and high frequency (HF) bands, in the power spectrum of HR variability. On the basis of these data, we defined two frequency bands of interest: LF (0.07-0.7 Hz) and HF (0.7-3.0 Hz). The power of LF was higher than that of HF in the normal guinea pigs. Atropine significantly reduced power at HF. Propranolol also significantly reduced power at LF. Furthermore, the decrease in the parasympathetic mechanism produced by atropine was reflected in a slight increase in the LF/HF ratio. The LF/HF ratio appeared to follow the reductions of sympathetic activity produced by propranolol. Autonomic blockade studies indicated that the HF component reflected parasympathetic activity and the LF/HF ratio seemed to be a convenient index of autonomic balance. Nocturnal patterns, in which the values of heart rate in the dark phase (20:00-06:00) were higher than those in the light phase (06:00-20:00), were observed. However, the HF, LF and the LF/HF ratio showed no daily pattern. These results suggest that the autonomic nervous function in guinea pigs has no clear circadian rhythmicity. Therefore, this information may be useful for future studies concerning the autonomic nervous function in this species.     

Effects of estrogen on gender-related autonomic differences in humans

Our previous studies demonstrated that premenopausal women have dominant vagal and subordinate sympathetic activity compared with age-matched men. This study was designed to investigate the role of estrogen in gender-related autonomic differences. We evaluated the heart rate variability of four healthy groups: age-matched postmenopausal women without hormone replacement therapy (PM), postmenopausal women on conjugated estrogen replacement therapy (PME), men, and non-age-matched premenopausal women (PreM). Frequency-domain analysis of short-term and stationary R-R intervals was performed to evaluate low-frequency power (LF; 0.04-0.15 Hz), high-frequency power (HF; 0.15-0.40 Hz), the ratio of LF to HF (LF/HF), and LF in normalized units (LF%). No gender-related autonomic differences existed between the PM and men groups, but they did exist between the PME and men group. Compared with the PreM group, the PM group had a lower HF and higher LF% and LF/HF. Compared with the PM group, the PME group had a higher HF but lower LF% and LF/HF. These results suggest that conjugated estrogen replacement therapy may facilitate vagal and attenuate sympathetic regulation of heart rate in postmenopausal women. In addition, estrogen may play an important role in gender-related autonomic differences.     

Selective quantification of the cardiac sympathetic and parasympathetic nervous systems by multisignal analysis of cardiorespiratory variability

Heart rate (HR) power spectral indexes are limited as measures of the cardiac autonomic nervous systems (CANS) in that they neither offer an effective marker of the beta-sympathetic nervous system (SNS) due to its overlap with the parasympathetic nervous system (PNS) in the low-frequency (LF) band nor afford specific measures of the CANS due to input contributions to HR [e.g., arterial blood pressure (ABP) and instantaneous lung volume (ILV)]. We derived new PNS and SNS indexes by multisignal analysis of cardiorespiratory variability. The basic idea was to identify the autonomically mediated transfer functions relating fluctuations in ILV to HR (ILV-->HR) and fluctuations in ABP to HR (ABP-->HR) so as to eliminate the input contributions to HR and then separate each estimated transfer function in the time domain into PNS and SNS indexes using physiological knowledge. We evaluated these indexes with respect to selective pharmacological autonomic nervous blockade in 14 humans. Our results showed that the PNS index derived from the ABP-->HR transfer function was correctly decreased after vagal and double (vagal + beta-sympathetic) blockade (P < 0.01) and did not change after beta-sympathetic blockade, whereas the SNS index derived from the same transfer function was correctly reduced after beta-sympathetic blockade in the standing posture and double blockade (P < 0.05) and remained the same after vagal blockade. However, this SNS index did not significantly decrease after beta-sympathetic blockade in the supine posture. Overall, these predictions were better than those provided by the traditional high-frequency (HF) power, LF-to-HF ratio, and normalized LF power of HR variability.     

Preeclamptic pregnancy is associated with increased sympathetic and decreased parasympathetic control of HR

Previous work from our laboratory using heart rate variability (HRV) has demonstrated that women before menopause have a more dominant parasympathetic and less effective sympathetic regulations of heart rate compared with men. Because it is still not clear whether normal or preeclamptic pregnancy coincides with alternations in the autonomic functions, we evaluated the changes of HRV in 17 nonpregnant, 17 normotensive pregnant, and 11 preeclamptic women who were clinically diagnosed without history of diabetic neuropathy, cardiac arrhythmia, and other cardiovascular diseases. Frequency-domain analysis of short-term, stationary R-R intervals was performed to evaluate the total variance, low-frequency power (LF; 0.04-0.15 Hz), high-frequency power (HF; 0.15-0.40 Hz), ratio of LF to HF (LF/HF), and LF in normalized units (LF%). Natural logarithm transformation was applied to variance, LF, HF, and LF/HF for the adjustment of the skewness of distribution. We found that the normal pregnant group had a lower R-R value and HF but had a higher LF/HF and LF% compared with the nonpregnant group. The preeclamptic group had lower HF but higher LF/HF compared with either the normal pregnant or nonpregnant group. Our results suggest that normal pregnancy is associated with a facilitation of sympathetic regulation and an attenuation of parasympathetic influence of heart rate, and such alterations are enhanced in preeclamptic pregnancy.     

Power spectral analysis of heart rate variability for assessment of diurnal variation of autonomic nervous activity in miniature swine.

BACKGROUND AND PURPOSES: The purpose of the study was to document diurnal variation of autonomic nervous functions by use of power spectral analysis of heart rate (HR) variability. METHODS: To clarify characteristics of power spectral analysis of HR variability, electrocardiogram (ECG), blood pressure (BP), and respiratory (Resp) waveform simultaneously were recorded. RESULTS: Two major spectral components were examined at low (LF)- and high (HF)-frequency bands for HR variability. Coherence between HR and Resp variabilities and HR and BP variabilities was maximal at approximately 0.14 and 0.03 Hz, respectively. On the basis of these data, two frequency bands of interest--LF (0.01 to 0.07 Hz) and HF (0.07 to 1.0 Hz)--were defined. Autonomic blockade studies indicated that the parasympathetic system mediated the HF and LF components, whereas the sympathetic system mediated only the LF component; HR had a diurnal pattern. The LF and HF bands in the dark phase tended to be higher than those in the light phase. The LF-to-HF ratio had a diurnal pattern similar to that of the HR. CONCLUSION: Parasympathetic nervous activity in miniature swine may be predominant in the dark phase. The characteristics of power spectra and diurnal variations of autonomic nervous functions are almost the same as those of humans. Therefore, miniature swine may be a useful animal model for future biobehavioral and pharmacotoxicologic studies.