硝酸甘油激发的倾斜试验在血管迷走性晕厥中的应用

目的了解在倾斜试验中,用硝酸甘油进行激发对于血管迷走性晕厥(vasovagalsyncope,VVS)患者的诊断价值,通过观察VVS患者晕厥前后的血流动力学改变及心率变异性功率谱变化,探讨VVS的发病机制。方法55例不明原因,反复发作的晕厥患者及20例健康人行直立倾斜试验,倾斜75°持续45min,阴性者舌下含服0.3mg硝酸甘油后倾斜至75°持续20min,观察有无阳性反应。倾斜过程中动态监测心电图、血压和心率,并进行心率变异性分析。结果病例组55例中32例出现阳性反应,8例于基础倾斜试验阶段出现阳性反应,24例于硝酸甘油激发后出现阳性反应,阳性率从14.55%升高到58.18%。阳性反应中,血管抑制型(VD)21例,占65.63%,心脏抑制型(CI)5例,占15.63%,混合型(MX)6例,占18.75%。对照组20例中4例出现阳性反应。CI型患者倾斜后心率上升,达高峰后在短期内急剧下降,发生晕厥,血压也略下降;MX型患者晕厥时心率及血压均在短期内急剧下降;VD型患者晕厥时血压在短期内急剧下降,心率也发生一定程度的下降,下降百分比小于CI型及MX型(P<0.05)。倾斜后阳性组LFnorm增高,HFnorm下降,LF/HF增高,晕厥前LFnorm及LF/HF达到最大值,HFnorm达到最低值,晕厥时LFnorm及LF/HF显著下降,HFnorm增加。结论硝酸甘油激发能增加倾斜试验的阳性率,自主神经功能改变(交感活性迅速减退,迷走神经兴奋)为晕厥产生的主要机制,并在不同患者产生不同的血流动力学改变。     

硝酸甘油激发的倾斜试验在血管迷走性晕厥中的应用

目的:了解在倾斜试验中,用硝酸甘油进行激发对于血管迷走性晕厥(VVS)患者的诊断价值,并通过观察VVS患者晕厥前后的血流动力学改变及心率变异性功率谱变化,以探讨VVS的发病机制。方法:55例不明原因反复发作晕厥患者(病例组)及20例健康者(对照组)行直立倾斜试验,倾斜75°持续45min,阴性者舌下含服0.3mg硝酸甘油后倾斜至75°持续20min,观察有无阳性反应。倾斜过程中动态监测心电图、血压和心率,并进行心率变异性分析。结果:病例组55例中32例出现阳性反应(阳性率为58.2%),8例于基础倾斜试验阶段出现阳性反应,24例于硝酸甘油激发后出现阳性反应;32例中,血管抑制型(VD型)21例,心脏抑制型(CI)5例,混合型(MX)6例。对照组20例中4例出现阳性反应。病例组中CI型患者倾斜后心率上升,达高峰后在短期内急剧下降,发生晕厥,血压也略下降;MX型患者晕厥时心率及血压均在短期内急剧下降;VD型患者晕厥时血压在短期内急剧下降,心率也发生一定程度的下降,下降百分比小于CI型及MX型(P<0.05)。倾斜后阳性者低频标化植(LFnorm)增高,高频标化值(HFnorm)下降,低高频比值(LF/HF)增高,晕厥前LFnorm及LF/HF达到最大值,HFnorm达到最低值,晕厥时LFnorm及LF/HF显著下降,HFnorm增加。结论:硝酸甘油激发能增加倾斜试验的阳性率,自主神经功能改变(交感活性迅速减退,迷走神经兴奋)为晕厥产生的主要机制,并在不同患者产生不同的血流动力学改变。     

倾斜试验中晕厥患者自主神经功能的变化

目的　运用频谱法研究直立倾斜试验中血管性晕厥的发生机制。方法　对 2 7例不明原因晕厥患者行直立倾斜试验 ,运用频谱法计算低频 (LF)、高频 (HF)及LF/HF的变化。结果　 15例发生晕厥或先兆晕厥 (阳性组 ) ,12例未出现症状 (阴性组 ) ,倾斜前两组LF、HF和LF/HF差异无显著性 ;阴性组倾斜后即刻HF明显下降 ,LF/HF显著升高 ,平卧后恢复到倾斜前水平 ,阳性组晕厥或先兆晕厥发作时 ,HF突然升高 (10 4 7± 4 0 4→ 32 95± 10 4 8) ,明显高于倾斜前 (2 3 4 4± 4 2 0→32 95± 10 4 8,P <0 0 5 ) ,LF/HF显著下降 (3 2 8± 0 39→ 1 0 7± 0 31,P <0 0 1) ,试验终止平卧后 ,HF和LF/HF恢复 ,两组LF在倾斜前后不同阶段均无明显变化。结论　在平卧、静息状态下 ,阳性患者和阴性患者的自主神经功能差异无显著性 ,倾斜后阳性患者迷走神经兴奋性在抑制过程中突然过度增强 ,导致晕厥或先兆晕厥发生。     

177例血管迷走性晕厥的临床特征及治疗转归

目的对血管迷走性晕厥(VVS)患者的临床特征及治疗转归进行总结。方法 177例患者经倾斜试验确诊为VVS,对其VVS的类型、年龄段分类、发作晕厥的症状和体征、不同季节发生情况以及治疗转归进行统计。结果血管抑制型56例、心脏抑制型6例、混合抑制型115例,分别占31.6%、3.4%、65.0%。所有患者在晕厥发生前均有心率突然增快,继之突然下降的过程,可表现为窦性心动过缓、心脏停搏等心率缓慢的症状。倾斜试验阳性与季节似乎无关。年龄在40～59岁之间的人群中VVS发生较高。β受体阻滞剂治疗VVS有效。结论 VVS可能是自主神经失调所致,β受体阻滞剂抗交感治疗有效。     

电针治疗糖尿病大鼠DCAN的HRV频阈分析

目的探讨电针对2型糖尿病大鼠糖尿病心脏自主神经病变(DCAN)的心率变异性(HRV)频阈值的表现与差异。方法 60只SD雄性大鼠随机分为空白对照组、糖尿病(DM)模型组、电针1组、电针2组。除空白对照组外,其余3组给予高脂高糖喂养4 w后,采用链脲佐菌素(STZ)连续2 d 25 mg/kg腹腔注射制作实验性DM大鼠模型。造模2 w后,空白对照组和DM模型组不予治疗;电针1组选内关、曲池、后三里、三阴交;电针2组选肺俞、心俞、胰俞、脾俞、肾俞。每日治疗1次,6 d为1个疗程,连续治疗4个疗程,疗程间休息1 d。检测4组大鼠各阶段体重、空腹血糖(FPG)、随机血糖(RBS)及治疗前后低频标化(LFnorm)、高频标化(HFnorm)、低频(LF)/高频(HF)等指标。结果造模2 w后,DM模型组、电针1组、电针2组大鼠体重下降,FPG、RBS水平上升明显,心率加快,LFnorm、HFnorm、LF/HF显著上升,与空白对照组比较差异有统计学意义(P0.05)。电针治疗4 w后,DM模型组体重下降,FPG、RBS水平持续上升,心率减慢,LFnorm、HFnorm、LF/HF下降,与空白对照组比较差异有统计学意义(P0.05);电针组均表现为体重轻度上升;FPG下降,心率回升,LFnorm、HFnorm、LF/HF回升,与DM模型组比较差异有统计学意义(P0.05)。电针1、2组HRV频阈值回升率分别为:LFnorm(60.76%/24.38%)、HFnorm(91.54%/81.65%)、LF/HF(43.10%/20.69%)。结论电针肢体腧穴对DM模型大鼠FPG有良好的调整作用,且优于躯体选穴组。电针对于自主神经系统具有一定的调节作用,能够降低交感神经的活性,提高迷走神经张力,调节自主神经的平衡性,增高HRV。     

特发性室性早搏与自主神经张力的关系

目的 探讨特发性室性早搏(室早)的发生与自主神经机制之间的关系.方法 采用单中心回顾性研究方法,选择24 h动态心电图记录到频发室早(≥10000次/d或室早负荷≥10％)的156例特发性室早患者(室早组)和同期健康体检者84例(对照组)为研究对象.根据24 h动态心电图检查结果,计算心率变异性指标rMSSD、pNN50、高频功率(HF)、标准化的高频功率(HFnorm)、低频功率(LF)与HF的比值(LF/HF).比较两组自主神经张力间的差异,并分析室早负荷与自主神经张力变化的关系.结果 与对照组相比,室早组患者rMSSD、pNN50、HF和HFnorm均明显增加(P<0.01),LF/HF显著降低(P<0.01).室早组患者24 h室早负荷与rMSSD、pNN50和HF呈正相关(相关系数分别为0.492、0.425、0.372,P<0.01),而与LF/HF呈负相关(相关系数为-0.206,P<0.05);其中28.8％(45/156)的患者每小时室早负荷与每小时HFnorm呈正相关,16.0％(25/156)的患者与每小时LF/HF呈正相关,53.8％(84/156)的患者与每小时HFnorm和每小时LF/HF均无相关性.结论 部分特发性室早的发生与交感和(或)迷走神经张力变化相关.     

心血管神经机能症的短时心率变异研究

应用短时心率变异（HRV）分析研究108例心血管神经机能症患者站卧两个体位的自主神经功能。结果显示：与正常人相比，心血管神经机能症患者站卧位的SDNN、HRVindex、RMSSD、PNN50、TP、LF、HF、HFnorm均低于正常人（P＜0．01）；而LF／HF、LFnorm高于正常人（P＜0．05）；正常人由卧位转为站位时，自主神经发生相应调节，表现交感神经活性增加，迷走神经活性降低。心血管神经机能症患者卧位变站位时HRV变化趋势与正常人基本相同，只是变化程度减小（LF／HF除外）。正常人SDNN、HRVindex、RMSSD、PNNS50、TP、LF、HFnorm与年龄呈负相关（P＜0．05）。心血管神经机能症患者除站位LF外，HRV各指标与年龄的相关比较均P＞0．05。     

左房线性消融治疗阵发性心房颤动对心率变异性的影响

目的通过观察左房线性消融术治疗阵发性心房颤动(简称房颤)术后心率变异性(HRV)的变化来评价其对自主神经系统的影响。方法对25例行射频消融术的阵发性房颤患者,术前及术后第3天行24h动态心电图检查,分别测定最大心率,最小心率,平均心率;时域指标:RR间期标准差(SDNN),RR间期平均值的标准差(SDANN),相邻RR间期差的均方根(RMMSD),相邻RR间期差值超过50ms的RR间期所占百分数(PNN50);频域指标:低频功率(LF),高频功率(HF),低频高频比值(LF/HF)。结果患者术前最大心率,最小心率,平均心率,SDNN,SDANN,RMSSD,PNN50,LF,HF,LF/HF分别为151±41次/分,47±5次/分,70±9次/分,126±26ms,111±24ms,27±7ms,6±5ms,98±66ms2,86±119ms2,2.4±3.5;术后各指标分别为136±37次/分,66±8次/分,84±9次/分,57±17ms,53±17ms,16±7ms,2±3ms,18±19ms2,16±19ms2,1.2±1.6;手术前后各指标相比,差异有显著性(P均<0.05)。结论左房线性消融术后HRV降低,此可能是射频消融治疗房颤的机制之一。     

倾斜训练对血管迷走性晕厥患者的治疗作用

目的 观察倾斜训练对血管迷走性晕厥(VVS)的治疗作用和可能机制，为采用物理方法治疗VVS提供新思路。方法 8名临床诊断为VVS且两次基础倾斜试验阳性患者，每天完成1次头高位75°的倾斜训练，连续5 d。治疗后进行基础倾斜试验，并记录试验血压、心率以及心脏泵血功能的变化。结果 倾斜训练治疗后8名患者的基础倾斜试验均转为阴性。与倾斜训练前相比，倾斜训练后平卧位时患者心率变异性低频功率、低频功率/高频功率显著升高（P<0.05），高频功率显著降低（P<0.05）；在倾斜试验终点时患者每搏量和血压显著升高（P<0.05），心率显著降低（P<0.01）。结论 每天1次、连续5 d的倾斜训练可以恢复VVS患者的立位耐力，其可能主要与改善自主神经功能、增强交感神经兴奋性和外周血管收缩能力有关。     

血管迷走性晕厥三种反应类型的心率变异分析

目的对倾斜试验(HUT)中三种不同反应类型的血管迷走性晕厥(VVS)患者进行心率变异分析(HRV)，探讨其不同的发病机制。方法54例不明原因晕厥患者倾斜75度进行持续45min的基础倾斜试验(BHUT)或只到发生晕厥，阴性患者于BHUT结束时恢复到平卧位，含服硝酸甘油0．3mg，然后倾斜75度进行持续20min的硝酸甘油诱导的倾斜试验(NTHUT)或只到发生晕厥，试验过程中进行间隔3min的心率变异分析。结果VVS患者中，血管抑制型(VD)和心脏抑制型(CI)均为8例，阳性率为14．8l％；混合型(MX)10例，阳性率为18．52％。倾斜75度后三组VVS患者的LFn值均增大，HFn值均减小；晕厥前3min时三组VVS的LFn值均升至最高，HFn值降至最低；晕厥时三组VVS患者的LFn值与晕厥前3min相比明显下降，但与倾斜前相比无明显差异；CI和MX组的HFn值与晕厥前3min相比明显增高，与倾斜前相比变化不大，VD组的HFn值与晕厥前3min相比无明显差异；未晕厥组在HUT过程中交感神经活性逐渐增大，试验结束时达到最大，迷走神经活性逐渐减小，试验结束时达到最小。结论VVS的发生与自主神经功能障碍有关，不同类型的VVS患者具有不同的神经调节障碍。     

直立倾斜试验对老年不明原因晕厥患者的诊断价值

目的：探讨直立倾斜试验对老年不明原因晕厥患者的诊断价值。方法：对140例老年不明原因晕厥患者在安静环境下进行直立倾斜试验．持续监测心率和血压变化。结果：140例老年不明原因晕厥患者在直立倾斜试验中,阳性反应80例（男43例．女37例）。其中血管抑制型39例（男21例,女18例）,心脏抑制剂9例（男4例,女5例）,混合刑32例（男18例,女14例）。血管抑制型患者晕厥时与晕厥前相比,血压从（122±14／69±15）mm—Hg下降到（82±15／45±10）mmHg（P〈0．01）;心脏抑制剂患者晕厥前心率为（95±17）次／min．晕厥时下降至（51土8）次／min（P〈0．01）;混合型患者晕厥前心率为（110±21）次／min。晕厥时下降至（63±21）次／min（P〈0．01）,血压从（115±18／65±18）mmHg下降到（83±19／46±10）mmHg（P〈0．01）。结论：直立倾斜试验是诊断老年不明原因晕厥的有效方法,血管抑制型是其最常见的类型．其阳性率和血流动力学模式分布在性别上无显著性差异。     

Inadequate sympathovagal balance in response to orthostatism in patients with unexplained syncope and a positive head up tilt test

AIM—To analyse the immediate response of heart rate variability (HRV) in response to orthostatic stress in unexplained syncope.
SUBJECTS—69 subjects, mean (SD) age 42 (18) years, undergoing 60° head up tilt to evaluate unexplained syncope.
METHODS—Based on 256 second ECG samples obtained during supine and upright phases, spectral analyses of low (LF) and high frequency (HF) bands were calculated, as well as the LF/HF power ratio, reflecting the sympathovagal balance. All variables were measured just before tilt during the last five minutes of the supine position, during the first five minutes of head up tilt, and just before the end of passive tilt.
RESULTS—Symptoms occurred in 42 subjects (vasovagal syncope in 37; psychogenic syncope in five). Resting haemodynamics and HRV indices were similar in subjects with and without syncope. Immediately after assuming the upright posture, adaptation to orthostatism differed between the two groups in that the LF/HF power ratio decreased by 11% from supine (from 2.7 (1.5) to 2.4 (1.2)) in the positive test group, while it increased by 11.5% (from 2.8 (1.5) to 3.1 (1.7)) in the negative test group (p = 0.02). This was because subjects with a positive test did not have the same increment in LF power with tilting as those with a negative test (11% v 28%, p = 0.04), while HF power did not alter. A decreased LF/HF power ratio persisted throughout head up tilt and was the only variable found to discriminate between subjects with positive and negative test results (p = 0.005, multivariate analysis). During the first five minutes of tilt, a decreased LF/HF power ratio occurred in 33 of 37 subjects in the positive group and three of 27 in the negative group. Thus a decreased LF/HF ratio had 89% sensitivity, 89% specificity, a 92% positive predictive value, and an 86% negative predictive value.
CONCLUSIONS—Through the LF/HF power ratio, spectral analysis of HRV was highly correlated with head up tilt results. Subjects developing syncope late during continued head up tilt have a decrease in LF/HF ratio immediately after assuming the upright posture, implying that although symptoms have not developed the vasovagal reaction may already have begun. This emphasises the major role of the autonomic nervous system in the genesis of vasovagal (neurally mediated) syncope.


Keywords: heart rate variability; vasovagal syncope; head up tilt test     

阻塞性睡眠呼吸暂停综合征心率变异性的变化及其意义

目的 :研究阻塞性睡眠呼吸暂停综合征 （OSAS）患者心率变异性 （HRV ）的变化。方法 :经夜间多导睡眠图（PSG） 7h监测及动态心电图检查 ,选取重度 OSAS患者及正常受试者各 2 0例 ,采用时域法和频域法分析 HRV。结果 :OSAS组与对照组比较时域指标 SDANN ,SDNN ,r MSSD显著增高 ,SDNN- index则显著降低 ,频域指标VL F,L F,HF,L Fnrom,HFnorm及 L F/HF均较对照组显著增高。结论 :OSAS患者交感神经及副交感神经活动均增强 ,交感神经活动增强占优势     

Long-term predictive power of heart rate variability on all-cause mortality in the diabetic population

To examine the long-term predictive power of heart rate variability (HRV) on all-cause mortality in randomly selected diabetic individuals. A total of 240 diabetic persons were randomly selected from the diabetic population. A 24-h ECG was obtained for each person included and analysed on the Pathfinder 700. In the RR Tools Program time (SDNN, SDANN, SDNN index, RMSSD, NN50, Triangular index) and frequency domain parameters (total power, VLF, LF, LFnorm, HF, HFnorm, HF/LF) were computed. After 15½ years vital statistics were obtained. The analysis included 165 persons with acceptable ECG recordings. 81 individuals (49%) died during follow-up. Correcting for age and gender we found that in time domain, only the SDNN index was a significant mortality predictor but in the frequency domain, all parameters were significantly associated with death. In multivariate analysis only the power in the low frequency band was an independent predictor. During the period following the first 5 years, the baseline LF continued to be a significant predictor of mortality. This long-term follow-up study indicates that the LF power is the strongest HRV predictor with regard to mortality. A reduced HRV at baseline still holds prognostic information after 5 years.     

Simultaneous analysis of heart rate variability and myocardial contractility during head-up tilt in patients with vasovagal syncope

INTRODUCTION: The aim of this study was to evaluate simultaneously cardiac autonomic activity, through heart rate variability (HRV) analysis, and cardiac inotropic changes during head-up tilt (HUT) in patients with recurrent vasovagal syncope. METHODS AND RESULTS: Twelve subjects implanted with a permanent dual-chamber pacemaker for recurrent vasovagal syncope characterized by marked bradycardia were studied. The tip of the right ventricular electrode was equipped with a sensor that measured peak endocardial acceleration (PEA) as an index of myocardial contractility. RR interval and PEA signals were acquired simultaneously and processed in the time and frequency (low frequencies [LF] and high frequencies [HF] of RR signal) domain during early HUT (T1), late HUT, or before syncope (T2). In the six subjects with positive HUT: (1) Abnormal heart rate oscillations were evidenced at T1 and discriminated this group from the negative group (LF/HF decreased by 46% from supine to T1, but increased by 55% in the negative group; P < 0.01 positive vs negative HUT). (2) Gradual diminution of the HF component was associated with an increase in PEA index during HUT with a correlation between PEA/RR interval (R = -0.8, P < 0.001), PEA/HF components (R = -0.6, P < 0.05). (3) Sympathetic stimulation responsible for changes in both HRV and PEA parameters occurred immediately before the faint (LF/LF+HF: 0.6 +/- 0.2 to 0.8 +/- 0.09; P < 0.05 T2 vs T1; PEA: 0.62 +/- 0.10G to 0.83 +/- 0.22G; P < 0.01 T2 vs T1). CONCLUSION: Our findings showed that a homogeneous subgroup of patients with recurrent vasovagal syncope and positive HUT exhibited abnormal cardiac autonomic and inotropic responses to an orthostatic stimulus. Continuous changes over time of HRV and PEA parameters highlight the dynamic behavior of the mechanisms leading to syncope.     

上腹部手术不同麻醉方法对心率变异性的影响

目的 :探讨上腹部手术不同麻醉方法对心率变异性 （HRV）的影响。方法 :30例择期上腹部手术患者分为全麻复合硬膜外腔麻醉 （CA）组和全麻 （GA）组。测定麻醉前 （T0 ）、气管插管后 5 m in（T1）、腹腔探查时 （T2 ）、术中 1h（T3）和 2 h（T4）、术毕拔气管导管前 （T5 ）和拔气管导管后 15 min（T6 ）的 HRV。结果 :与 T0相比 ,CA组标化低频值 （L Fnorm）在 T2 ,T3,T4,T5和 T6均显著降低 （P<0 .0 1） ,L F/ HF在 T1,T2 ,T3和 T4也均显著降低 （P<0 .0 1）。 GA组围麻醉期 HRV的各项数据均无显著变化。组间比较 ,CA组 L Fnorm在 T3显著低于 GA组 （P<0 .0 5 ） ,L F/ HF在 T3和 T4也显著低于 GA组 （P<0 .0 5 ）。结论 :全麻下行上腹部手术心脏自主神经功能稳定 ,而全麻复合硬膜外腔麻醉显著抑制交感神经     

Effect of weight loss on sympatho-vagal balance in subjects with grade-3 obesity: restrictive surgery versus hypocaloric diet

Few and mostly uncontrolled studies indicate that weight loss improves heart rate variability (HRV) in grade-3 obesity. The aim of this study was to compare in grade-3 obesity surgery and hypocaloric diet on clinical and metabolic variables and on autonomic indices of HRV. Twenty-four subjects (body mass index, BMI 45.5 ± 9.13 kg/m²) underwent surgery (n = 12, gastric banding, LAGB) or received hypocaloric diet (n = 12, 1,000–1,200 kg/day). Clinical [BMI, systolic blood pressure (SBP) and diastolic blood pressure (DBP), heart rate] and metabolic variables [glucose, cholesterol, HDL- and LDL-cholesterol, triglycerides, AST and ALT transaminases] and 24-h Holter electrocardiographic-derived HRV parameters [R–R interval, standard deviation of R–R intervals (SDNN); low/high-frequency (LF/HF) ratio, and QT interval] were measured at baseline and after 6 months. The two groups were identical at baseline. BMI (?7.5 ± 3.57 kg/m², mean ± SD), glucose (?24.1 ± 26.77 mg/dL), SBP (?16.7 ± 22.19 mmHg) and DBP (?6.2 ± 8.56 mmHg) decreased in LAGB subjects (p < 0.05) and remained unchanged in controls. At 6 months, SDNN increased in LAGB subjects (+25.0 ± 37.19 ms, p < 0.05) and LF/HF ratio diminished (2.9 ± 1.84 vs. 4.9 ± 2.78; p = 0.01), with no change in controls; LF (daytime) and HF (24 h and daytime) increased in LAGB subjects, with no change in controls. Decrease in BMI correlated with SBP and DBP decrease (p < 0.05), and DBP decrease correlated with HR decrease (p < 0.05) and QT shortening (p < 0.05). Weight loss is associated with improvement of glucose metabolism, of blood pressure, and with changes in time and frequency domain parameters of HRV; all these changes indicate recovery of a more physiological autonomic control, with increase in parasympathetic and reduction in sympathetic indices of HRV.