Effects of Hormone Replacement Therapy on Heart Rate Variability in Postmenopausal Women

Background: Hormone replacement therapy (HRT) is associated with reduced cardiovascular risk, but the underlying mechanism(s) are not fully understood. This study investigated the effects of a 6‐month course of HRT on cardiac autonomic function parameters assessed by heart rate variability (HRV) in postmenopausal women. Methods: Forty‐six healthy postmenopausal women (age 48 ± 5, range 40–60) with normal baseline electrocardiogram and negative exercise testing were enrolled. HRT, which was either 0.625 mg/day conjugated equine estrogen (CEE) plus 2.5 mg/day medroxyprogesterone acetate or 0.625 mg/day CEE alone were administered depending on hysterectomy status. Power spectral analysis of HRV was performed to calculate the low frequency component in absolute (LF) and normalized units (LF nu), high frequency component in absolute (HF), and normalized units (HF nu), and the LF/HF ratio. The standard deviation of RR intervals (SDNN) was calculated from the time series of RR intervals. Results: A 6‐month course of HRT did not significantly alter resting heart rate (P > 0.05). The LF/HF ratio and LF nu significantly decreased after HRT (P = 0.022 and P = 0.032), whereas a significant increase was noted in the HF component of HRV (P = 0.043), indicating an improvement in cardiac autonomic function. The SDNN value, which was 28.8 ± 11.8 ms before HRT significantly increased to 35.4 ± 16.7 ms after 6 months (P = 0.011). Conclusion: Our results indicate that a 6‐month course of HRT may significantly improve cardiac autonomic function parameters, a finding that could at least partly explain the potential cardiopro‐tective effect(s) of HRT. A.N.E. 2001;6(4):280–284     

Reduced parasympathetic tone in newly diagnosed essential hypertension

AimThe aim of the study was to compare heart rate variability (HRV) of newly diagnosed essential hypertensive subjects with controls.MethodsThe study was conducted on 120 hypertensive subjects and 120 controls.ResultsThe time-domain measures, standard deviation of all RR intervals (SDNN), the square root of the mean of the sum of the squares of differences between adjacent RR intervals (RMSSD), and percentage of consecutive RR intervals that differ by more than 50 ms (pNN50) which reflect parasympathetic activity were significantly less in hypertensive subjects. In frequency-domain measures, high frequency [HF (ms²)] and [HF (nu)], which reflects parasympathetic activity, was significantly less in hypertensive subjects while LF (nu) and LF/HF (%), which reflect sympathetic activity, were comparable between the groups.ConclusionThese findings suggest that HRV is reduced in subjects with newly diagnosed essential hypertension and the parasympathetic dysregulation is present in the early stage of essential hypertension.     

倍他乐克、洛汀新对心肌梗死后自主神经调控的影响

为评价倍他乐克、洛汀新对急性心肌梗死 (AMI)后自主神经的影响 ,并探讨其对AMI后心律失常的防治作用。 17条AMI模型狗被随机分为对照组、倍他乐克组和洛汀新组。测量AMI前、AMI后 1h和 4个月的心率变异(HRV) ,并在AMI后 4个月采用逐级右室快速起搏方法诱发心室颤动。时域分析指标以RR间期的标准差 (SDNN)和相邻RR间期差值平方和的均方根 (rMSSD)表示 ,频域分析包括高频 (HF 0 .15～ 0 .40Hz)、低频 (LF 0 .0 4～ 0 .15Hz)和极低频 (VLF 0 .0 0 33～ 0 .0 4Hz)。结果 :对照组中 ,SDNN、rMSSD、LF/HF在AMI后 4个月轻度恢复 ;倍他乐克组和洛汀新组在AMI后 4个月明显改善 ,与AMI后 1个月相比较 ,SDNN(188± 5 4vs 140± 44ms和 172± 32vs 12 7± 2 9ms)、rMSSD(32± 10vs 2 2± 5ms和 34± 8vs 2 3± 6ms)、HF(0 .48± 0 .0 2vs 0 .2 7± 0 .0 2ms2 和 0 .49± 0 .0 1vs 0 .2 7± 0 .0 1ms2 )、LF/HF(0 .6 5± 0 .0 3vs 1.74± 0 .15ms2 和 0 .6 7± 0 .0 3vs 1.6 9± 0 .11ms2 )差异有显著性 ,P均 <0 .0 5或 0 .0 1。三个实验组的心室颤动诱发率分别为 83% ,2 0 % ,3%。结论 :β受体阻断剂和血管紧张素转换酶抑制剂能改善AMI后的自主神经调控 ,防治AMI后室性心律失常的发生。     

实验性心肌缺血大鼠心脏自主神经活性的动态变化及意义

采用心率变异（ＨＲＶ）时域及频域指标分析急性心肌缺血２４ｈ大鼠心脏自主神经功能的变化以探讨其意义。将实验动物分成三组，即正常对照组（２０只）、假手术组（２０只）与心肌缺血组（４８只），并运用动态心电图记录２４ｈ心电信号变化。结果显示：与假手术组及正常对照组分别比较，心肌缺血组正常窦性心律ＲＲ间期标准差（ＳＤＮＮ）下降（２８．９±９．４ｍｓｖｓ３４．４±１３．７ｍｓ或３５．１±１４．３ｍｓ，Ｐ均＜０．０５），低频（ＬＦ）及低频与高频的比值（ＬＦ／ＨＦ）明显增加（１８９．４±３６．５ｍｓ２／Ｈｚｖｓ５７．３±１７．８ｍｓ２／Ｈｚ或５１．８±１８．６ｍｓ２／Ｈｚ；３．８５±０．９１ｖｓ１．７６±０．６３或１．６８±０．５７，Ｐ均＜０．０１）；２４ｈ心率功率谱示心肌缺血组ＬＦ及ＬＦ／ＨＦ波动幅度较假手术组及正常对照组增高，缺血大鼠ＬＦ与ＬＦ／ＨＦ在缺血后０～３ｈ（２６７．５±１２．４ｍｓ２／Ｈｚ、４．３３±１．０８）及９～１２ｈ（２４４．７±１３．９ｍｓ２／Ｈｚ、３．９６±０．９８）期间增高显著，而在缺血后５～７ｈ（１４９．２±８．７ｍｓ２／Ｈｚ、２．０５±０．４２）内则相对较低。结果表明大鼠心肌缺血后ＨＲＶ降低主?     

心得安改善短效钙拮抗剂心痛定心率变异性的研究

探讨β受体阻滞剂心得安是否可以改善短效钙拮抗剂心痛定的心率变异性(HRV)。将101例观察对象随机分为对照组(只使用心痛定,n=49)和试验组(使用心痛定和心得安,n=52),分别在服药前及服药后7～10天做24h动态心电图检测,分析HRV指标:正常RR间期的标准差(SDNN)、每5min平均RR间期的标准差(SDANN)、相邻RR之差的均方根(RMSSD)、相邻RR之差>50ms占总窦性心搏的百分数(PNN50)、低频(LF)、高频(HF)、低频和高频比值(LF/HF)。结果:对照组在治疗后心率(HR)加快,SDNN、SDANN显著降低(分别为105.2±31.8msvs126.9±32.0ms、98.9±20.1msvs107.9±19.8ms,P均<0.05),LF、LF/HF升高(分别229.3±77.1Hzvs196.1±64.8Hz、5.4±1.9vs3.8±1.8,P均<0.05),HRV降低;而试验组在治疗后心率无明显改变,SDNN、SDANN、LF、HF升高(分别为140.1±29.8msvs129.1±31.9ms、127.8±21.1msvs108.2±20.1ms、209.8±70.1Hzvs197.3±65.1Hz、148.5±48.8Hzvs123.5±41.0Hz,P均<0.05),LF/HF降低(P<0.05),治疗组HRV升高。结论:心得安能改善短效钙拮抗剂心痛定的HRV。     

经皮冠状动脉腔内成形术对不稳定型心绞痛患者心率变异的影响

应用长程心电图分析系统对１６例不稳定型心绞痛患者（ＵＡＰ组）入院后第２日、经皮冠状动脉腔内成形术（ＲＴＣＡ）后第１，３，３０日以及１４８例健康中、老年人（对照组）２４ｈ心电图进行心率变异（ＨＲＶ）分析。结果：ＵＡＰ组２４ｈ连续正常ＲＲ间期的标准差（ＳＤＮＮ）、２４ｈ内连续５ｍｉｎ节段平均正常ＲＲ间期的标准差（ＳＤＡＮＮｉ）、相邻ＲＲ间期差的均方根（ｒＭＳＳＤ），相邻两个正常心动周期差值大于５０ｍｓ个数占总搏数的百分比（ＰＮＮ５０）、低频功率（ＬＦ）及高频功率（ＨＦ）均明显低于对照组（分别为９２．７±１４．３ｍｓｖｓ１２８．９±１７．８ｍｓ、７８．８±１０．６ｍｓｖｓ１１８．６±１９．１ｍｓ、１９．３±７．７ｍｓｖｓ２９．８±１２．７ｍｓ、３．６±１．７％ｖｓ６．５±５．５％、３１７．２±１４８．３ｍｓ２ｖｓ４７６．５±２８７．３ｍｓ２，Ｐ均＜０．０５），而ＬＦ／ＨＦ高于对照组（３．５±１．３ｖｓ２．４±１．１，Ｐ＜０．０５）。ＰＴＣＡ术后３０天ＵＡＰ患者ＨＲＶ逐渐恢复正常。结果提示ＵＡＰ患者交感神经和迷走神经张力下降，而以后者更明显；ＰＴＣＡ后ＨＲＶ逐渐恢复，说明ＰＴＣＡ能改善ＵＡＰ患者的ＨＲＶ。     

Gabapentin therapy improves heart rate variability in diabetic patients with peripheral neuropathy

PurposeDiabetic cardiac neuropathy, which is characterized by reduced heart rate variability (HRV), frequently coexists with peripheral neuropathy. Gabapentin has been used for the treatment of diabetic neuropathy. We aimed to evaluate the possible effect of gabapentin treatment on autonomic function in patients with type 2 diabetes via HRV.MethodsThirty patients with type 2 diabetes mellitus and peripheral neuropathy and 28 age- and sex-matched healthy controls were consecutively registered. Each patient underwent HRV measurements, and diabetic patients were administered gabapentin. After 3 months of gabapentin therapy, HRV parameters were measured again.ResultsBaseline HRV parameters were blunted in patients with diabetes mellitus according to the controls [standard deviation of all NN intervals (SDNN, ms): 106.3±29.9 vs. 148.8±36.5, P=.001; power spectrum of the high-frequency band (HF, ms²): 133.6±98.3 to 231.4±197.6, P=.02; power spectrum of the low-frequency band (LF, ms²): 341.8±247.8 to 511.5±409.4, P=.048; LF/HF ratio: 3.3±2.4 to 2.6±1.5, P=.33]. After 3 months of treatment with gabapentin, some HRV parameters showed some improvement. SDNN (106.2±29.8 to 119.4 ± 25, P=.016) and HF (133.6±98.3 to 167.6±118.3, P=.021) increased significantly. LF/HF ratio decreased (from 3.3±2.4 to 2.3±1.9, P=.039) and LF remained unchanged (341.8±247.8 to 352.3±228.9, P=.88).ConclusionsTherapeutic doses of gabapentin not only alleviate neuropathic symptoms but also improve cardiac autonomic function in diabetic patients with peripheral neuropathy.     

T‐Wave Alternans and Heart Rate Variability: A Comparison in Patients with Myocardial Infarction with or without Diabetes Mellitus

Background : The aim of this study was to investigate the differences in T‐wave alternans (TWA) and heart rate variability (HRV) among patients with myocardial infarction with or without diabetes mellitus and the relationship between TWA and HRV. Methods: The study population included 133 patients: 59 patients with myocardial infarction (MI) (group post‐MI without diabetes); 40 myocardial infarction with diabetes (group post‐MI with diabetes); and 34 controls (group control). Cardiac autonomic neuropathy assessment was made using frequency domain (low‐frequency [LF] power, high‐frequency [HF] power, LF/HF) and time domain (SDNN, standard deviation of the averaged normal sinus RR intervals for all 5‐minute segments [SDANN]) of HRV indexes. Both TWA and HRV were measured on the Holter monitor, and TWA was calculated automatically using the time‐domain modified moving average method. Results: TWA values differed significantly between controls (40 ± 16 μV) and group post‐MI with (62 ± 17 μV, P < 0.05) or without (60 ± 15 μV, P < 0.05) diabetes. In addition, group post‐MI with diabetes had lower standard deviation of all normal sinus RR intervals (SDNN), standard deviation of the averaged normal sinus RR intervals for all 5‐minute segments (SDANN), and HF, indicating depressed vagus nerve activity, and higher LF/HF ratio, indicating elevated sympathetic nerve activity, than controls and group post‐MI without diabetes (P < 0.05). TWA correlated with SDNN and SDANN (r = 0.29, 0.31; P < 0.001). Conclusions: TWA was elevated in patients following myocardial infarction, both in those with or without diabetes. Myocardial infarction patients had a lower time domain, HF, and a higher LF/HF ratio HRV, especially in those with diabetes. The analysis of modified moving agerage (MMA)‐based TWA and HRV can be a useful tool for identifying post–myocardial infarction patients at high risk of arrhythmic events. Ann Noninvasive Electrocardiol 2011;16(3):232–238     

Noninvasive ventilation can modulate heart rate variability during high-intensity exercise in COPD-CHF patients

Objectiveto assess the acute effects of non-invasive ventilation (NIV) during high-intensity exercise on heart rate variability (HRV) responses in chronic obstructive pulmonary disease (COPD) and Chronic heart failure (CHF) patients.MethodsThis was randomized, double blinded and controlled study. Fourteen patients with COPD-HF diagnosis were evaluated. The subjects underwent to the following tests: (I) cardiopulmonary exercise testing (CPET) on a cycle ergometer ramp protocol; (II) 7 days after CPET, patients randomly underwent two constant-load exercise (CLE) with NIV or Sham ventilation until tolerance limit, with 80% of the CPET peak load. R-R intervals (RRi) were continuously collected during rest, exercise and in recovery. Time and frequency domain and nonlinear heart rate variability (HRV) indices were obtained.ResultsNIV resulted in a decrease of Mean iRR, square root of the mean squared differences of successive RRi (rMSSD), RR tri index and high-frequency (HF), nu (p < 0.05) and increase of Mean HR, low-frequency (LF), nu and LF/HF (p < 0.05) during exercise when compared to rest. In addition, NIV during exercise induced lower rMSSD and Sample Entropy when compared with Sham (p < 0.05). Negative correlation was found between forced expiratory volume in 1 second (FEV_1, L) vs HF (nu) during exercise with NIV (p = 0.04; r= -0.58). Furthermore, simple linear regression showed that the FEV₁ (L) affected 30% of the HF (nu) response during the exercise with NIV.ConclusionNIV during exercise produced enhanced heart rate and autonomic responses in COPD-CHF patients. Additionally, COPD severity is negatively associated with a higher vagal response during exercise with NIV.     

心率变异对甲状腺机能亢进患者自主神经功能的评价

采用短时采样的时域、频域法对１８例初诊甲状腺机能亢进（简称甲亢）患者（甲亢组）进行心率变异分析，并以１８例正常人作为对照（对照组），了解甲亢患者自主神经功能的改变。与对照组相比，甲亢组平均ＲＲ间期、ＲＲ平均值标准差、相邻ＲＲ间期差值的均方根、相邻ＲＲ间期相差＞５０ｍｓ占总心动周期数的百分比均明显降低（分别为５５４．５３±６７．７９ｍｓｖｓ８５８．３６±９０．４３ｍｓ、１６．４１±５．５０ｍｓｖｓ４３．０８±１１．０４ｍｓ、１１．３２±３．１６ｍｓｖｓ３７．４３±１０．１２ｍｓ、０．３３±０．５１％ｖｓ１５．２２±１２．８４％，Ｐ均＜０．００１）。极低频段成分明显升高、高频段（ＨＦ）成分明显降低（分别为３８．３２±８．６０ｍｓ２／Ｈｚｖｓ２５．１１±１０．７８ｍｓ２／Ｈｚ、１２．７７±７．０４ｍｓ２／Ｈｚｖｓ３５．６５±１５．０８ｍｓ２／Ｈｚ，Ｐ均＜０．００１）、低频段（ＬＦ）成分无明显改变（２７．１２±１１．３４ｍｓ２／Ｈｚｖｓ２９．６０±１０．３１ｍｓ２／Ｈｚ，Ｐ＞０．０５），ＬＦ／ＨＦ明显增高（２．７６±１．７１ｖｓ１．１７±１．０８，Ｐ＜０．００２），心率总功率谱密度无明显变化。提示甲亢患者不仅交感神?     

自主神经对心室晚电位各参数的昼夜影响

采用数字化Holter监测仪对 30例健康人进行连续监测 ,计算其心室晚电位 (VLP)及心率变异性 (HRV)指标的动态变化 ,以评价出两者之间的关系。所有健康受试者 ,均按立体正交导联方式佩戴 2 4h动态心电图 ,分别记录午夜 2时及下午 14时左右这两个时间点的VLP及HRV数值 :夜间LF 4 93.5 7± 15 6 .6 2ms2 ,HF 6 89.73± 172 .19ms2 ,LF/HF 0 .74 3± 0 .118,T QRS 10 0 .1± 12 .79ms ;白天LF 4 14 .75± 176 .6 1ms2 ,HF 318.5 1± 116 .6 1ms2 ,LF/HF 1.399± 0 .2 81,T QRS 90 .0 3± 9.70ms(P <0 .0 5 ) ,结果显示VLP与HRV均存在昼夜的明显变化 ,T QRS与HF在夜间均增高 ,白天均降低 ,且表现出明显的正相关 ;TQRS与LF/HF比值则表现出明显的负相关。结论 :VLP存在与自主神经相关的昼夜规律性变化。     

Cigarette Smoking and Heart Rate Variability: Dynamic Influence of Parasympathetic and Sympathetic Maneuvers

Background: Cigarette smoking has been associated with increased activity of the sympathetic nervous system. In this study, we investigated cardiac autonomic function in heavy smokers and nonsmoker controls by analysis of heart rate variability (HRV). Method: Twenty‐four long‐term heavy smokers (men) and twenty‐two nonsmoker subjects (hospital staff) were included to study. Time domain [mean R‐R interval (RR), the standard deviation of R‐R interval index (SDNN), and the root mean square of successive R‐R interval differences (RMSSD)] and frequency domain [high frequency (HF) low frequency (LF), and LF/HF ratio] parameters of HRV were obtained from all participants after 15 minutes resting period in supine position (S), during controlled respiration (CR), and handgrip exercise (HGE) over 5‐minute periods. Results: Baseline SDNN and RMSSD values were found to be lower in smokers than in nonsmokers. (64 ± 10 vs 78 ± 22, P < 0.05 and 35 ± 12 vs 54 ± 30 ms, P < 0.05). Baseline LF/HF ratio was also found to be higher in smokers than in nonsmokers (1.3 ± 0.6 vs 0.9 ± 0.5 ms, P < 0.05). The other HRV parameters including R‐R interval, LF, and HF were not significantly different. During CR, expected increase in RR, SDNN, and RMSSD did not occur in smokers, while it did occur in nonsmokers. Most HRV indices were significantly affected by HGE in both groups. In addition, the duration of smoking was found to be inversely correlated with RMSSD and HF and positively correlated with LF/HF ratio. Conclusion: Vagal modulation of the heart is blunted in heavy smokers, particularly during a parasympathetic maneuver. Blunted autonomic control of the heart may partly be associated with adverse event attributed to cigarette smoking.     

糖代谢正常的2型糖尿病患者后代心率变异性与血管内皮功能研究

目的 研究糖代谢正常的2型糖尿病患者一级亲属(FDRs)的心率变异性(HRV)及血管内皮功能,并与健康对照组进行比较.方法 测定37例(男17例,女20例)正常人、60例(男29例,女31例)FDRs的HRV及内皮依赖性血管舒张功能(EDV),同时测定BMI、血压、血脂、空腹胰岛素水平,计算HOMA胰岛素抵抗指数(HOMA-IR).结果 FDRs的HRV时域分析指标总体标准差(SDNN)(124.6±20.6)ms、均值标准差(SDANN)(110.1±20.1)ms、差值均方平方根(rMSSD)(33.9±9.2)ms及频域分析指标低频(1128.5±314.7)ms~2/Hz、高频(904.6±461.6)ms~2/Hz均低于正常对照组[SDNN(140.5±20.5)ms、SDANN(129.5±20.3)ms、rMSSD(40.9±11.4)ms、低频(1678.3±276.2)ms~2/Hz、高频(1112.6±513.7)ms~2/Hz],FDRs组EDV低于对照组[(5.10±0.14)%比(12.50±3.30)%],FDRs的HOMA-IR高于正常组[0.57±0.36比0.42.±0.23],差异均有统计学意义(P值均<0.05),且三者之间密切相关(P值均<0.01).结论 糖代谢正常的FDRs存在HRV降低、胰岛素抵抗及血管内皮功能受损,且三者相互影响.     

犬心率变异的实验研究

为了解正常犬心率变异（ＨＲＶ）的特征，以便在此基础上作各种病理模型的前瞻性ＨＲＶ研究。取健康成年杂种犬２０只，自由活动下记录２４ｈ心电图。ＨＲＶ分析采用时域、频域分析方法及构制２４ｈ三维频谱图及Ｐｏｉｎｃａｒｅ散点图。结果：２０只犬２４ｈ总心搏数为１３４６５２．６１±１６１９．３１次，平均心率为１０８．００±１６．６１ｂｐｍ。正常ＲＲ间期标准差（ＳＤＮＮ）、连续５ｍｉｎ正常ＲＲ间期标准差均值（ＳＤＡＮＮ）、连续５ｍｉｎ正常ＲＲ间期均值的标准差（ＳＤＮＮｉ）、相邻正常ＲＲ间期差值的均方根（ｒＭＳＳＤ）、相邻正常ＲＲ间期超过５０ｍｓ的百分比（ＰＮＮ５０）分别为１０８．００±４５．１１ｍｓ、９５．００±４３．８１ｍｓ、４１．４５±１８．０５ｍｓ、１９９．００±５４．４１ｍｓ、５６．００±１３．９４％。超低频成分（ＵＬＦ）、极低频成分（ＶＬＦ）、低频成分（ＬＦ）、高频成分（ＨＦ）、ＬＦ／ＨＦ分别为３８．００±３３．７６ｂｐｍ２／Ｈｚ、６１．００±４０．５８ｂｐｍ２／Ｈｚ、２７８．００±１６４．１７ｂｐｍ２／Ｈｚ、２７８．００±１９６．６０ｂｐｍ２／Ｈｚ、１．７３±２．５９。ｒＭＳＳＤ、ＨＦ等反映ＲＲ间期快速变化的成?     

正常人群的心率变异性分析

将１００４例正常人分三个年龄组进行短程（５ｍｉｎ）心率变异性（ＨＲＶ）分析。时域法的参数为平均心率标准差（ＨＲＳＤ），连续５ｍｉｎ节段平均正常ＲＲ间期标准差（ＳＤＡＮＮ），相邻ＲＲ间期差的均方根（ｒＭＳＳＤ），相邻ＲＲ间期差异≥５０ｍｓ的百分数（ＰＮＮ_（５０））；频域法的参数为极低频（ＶＬＦ）、低频（ＬＦ）、高频（ＨＦ）成分，总功率（ＴＰ）及ＬＦ／ＨＦ比值。各指标间做相关分析。结果：４５岁以上组ＨＲＳＤ、ＳＤＡＮＮ、ｒＭＳＳＤ、ＰＮＮ_（５０）、ＶＬＦ、ＬＦ、ＨＦ、ＴＰ均低于４５岁以下两组（Ｐ＜０．０５或＜０．０１）。ＳＤＡＮＮ、ｒＭＳＳＤ、ＰＮＮ_（５０）与ＨＦ呈高度正相关（ｒ＞０．７０，Ｐ＜０．０００１），其中以ＳＤＡＮＮ、ＰＮＮ_（５０）相关更好（ｒ＞０．７５，Ｐ＜０．００１），ＳＤＡＮＮ、ｒＭＳＳＤ、ＰＮＮ_（５０）间高度相关（ｒ＞０．８０，Ｐ＜０．０００１）。不同性别ＨＲＶ各参数相比无显著差异。提示：ＨＲＶ随年龄的增长而下降，以迷走神经张力下降为主；各指标中以ＳＤＡＮＮ、ｒＭＳＳＤ、ＰＮＮ_（５０）、ＨＦ能更好地反映迷走神经张力变化。     

年轻健康男性的心率变异性分析

目的:研究年轻健康男性心率变异性.方法:收集2001-2009年在我室参加临床药物试验的205例年轻健康男性的动态心电图(DCG)资料,分析年轻健康男性的心率变异性.结果:时域指标:平均RR间期的标准差(SDNN)、相邻RR间期差的均方根(rMSSD)、相差大于50ms的相邻RR间期占RR间期总数的百分比(PNN50)...     

The Relationship Between Heart Rate Recovery and Heart Rate Variability in Coronary Artery Disease

Background: Reduced heart rate recovery (HRR) in coronary artery disease (CAD) is predictive of increased cardiovascular mortality and is related to reduced parasympathetic tonus. Objective: To investigate HRR and heart rate variability (HRV) measured at steady state condition and the relationship between these two parameters in CAD. Materials and Methods: In our study, we enrolled 33 (28 males, mean age 52.4 ± 9.6 years) patients with CAD who did not have heart failure, atrial fibrillation, pacemaker, and any disease state that could affect the autonomic functions and 38 age‐matched healthy subjects (21 males, mean age 48.3 ± 7.8 years). All the patients underwent submaximal treadmill exercise testing (Bruce protocol). HRR was calculated by subtracting the heart rate values at the 1st, 2nd, and 3rd minutes of the recovery phase from the peak heart rate (HRR₁, HRR₂, HRR₃). Before exercise testing, short‐term steady state HRV analyses of all subjects were obtained with the time‐ and frequency‐domain methods and were correlated to HRR. For frequency‐domain analysis, low‐frequency HRV (LF, 0.004–0.15 Hz), high‐frequency HRV (HF, 0.15–0.5 Hz), and LF/HF ratio were measured for 5 minutes in the morning. For time‐domain analysis, standard deviation of the normal‐to‐normal NN intervals (SDNN), square root of the mean squared differences of successive N‐N intervals (RMSSD), and proportion derived by dividing the number of interval differences of successive N‐N intervals greater than 50 ms by the total number of N‐N intervals (pNN50) were obtained. Only HRR₃ was used for the correlation analysis. Results: In CAD groups, the HF, an indicator of parasympathetic activation, was significantly reduced, whereas the LF and LF/HF values, which are indicators of sympathetic activity, were increased (P = 0.0001 for each parameter). The time‐domain parameters SDNN, RMSSD, and pNN50 were significantly reduced in the patient group (P = 0.0001, P = 0.009, and P = 0.0001, respectively). Similar to the HRV parameters, the HRR₁, HRR₂, and HRR₃ values were significantly reduced in the patient group (P = 0.0001 for each parameter). We observed a significant negative correlation between HRR₃ and LF (r =?0.67, P = 0.0001) and between HRR₃ and LF/HF (r =?0.62, P < 0.0001), while there was a significant positive correlation between HRR₃ and HF, SDNN, RMSSD, and pNN50 (r = 0.69, P = 0.0001; r = 0.41, P = 0.0001; r = 0.31, P = 0.008; and r = 0.44, P = 0.0001). Conclusions: HRR and HRV are significantly reduced in CAD. The reduction in HRR is parallel to the changes in HRV parameters. HRR, which can be measured easily in the recovery phase of exercise testing, can be used to detect the depression of parasympathetic tonus and to evaluate the basal autonomic balance in this patient group.     

β-受体阻断剂和血管紧张素转换酶抑制剂对心肌梗死患者心率变异影响的比较

为了解β－受体阻断剂和血管紧张素转换酶抑制剂（ＡＣＥＩ）对心肌梗死患者心率变异（ＨＲＶ）的影响，采用惠普系列双通道动态心电图机对５３例急性心肌梗死（ＡＭＩ）和３２例陈旧性心肌梗死（ＯＭＩ）患者进行了ＨＲＶ分析。β－受体阻断剂治疗的ＡＭＩ患者（Ｂ组）与对照组（常规治疗的ＡＭＩ患者即Ｃ组）相比，２４ｈＲＲ间期总体标准差（ＳＤＮＮ）、相邻ＲＲ间期大于５０ｍｓ的百分比（ｐＮＮ５０）均增加（７．２６±３．４４ｍｓｖｓ４．２７±２．０１ｍｓ，１２６．３４±３０．０５ｖｓ９１．４８±２９．２１，Ｐ均＜０．０５），高频带（ＨＦ）增大（８．５３±１．９７ｍｓ２／Ｈｚｖｓ６．７２±２．０８ｍｓ２／Ｈｚ，Ｐ＜０．０５），低频带（ＬＦ）降低（１２．６４±３．０５ｍｓ２／Ｈｚｖｓ１５．３１±４．２１ｍｓ２／Ｈｚ，Ｐ＜０．０１）。ＡＣＥＩ治疗的ＡＭＩ患者（Ａ组）与对照组（ｃ组）相比，ｐＮＮ５０增加（１２３．５９±２７．６３ｖｓ９１．４８±２９．２１，Ｐ＜０．０５），低频与高频的比值降低（２．１３±１．０５ｖｓ２．３５±０．８７，Ｐ＜０．０５），其中伴有心力衰竭者与不伴心力衰竭者相比ＨＲＶ改善较显著。ＡＣＥＩ和β－受体阻断剂对ＯＭＩ患者?     

Compromise of the cardiac autonomic nervous system in patients with Fontan-type circulation: preliminary data

BACKGROUND: Rhythm disturbances are frequent after Fontan operations. Arrhythmias related to reduced heart rate variability (HRV) have been described in various cardiovascular diseases. METHODS: We attempted to investigate HRV in 12 patients who underwent Fontan operation (age 11.4 +/- 3 years). Results were compared to a control group of 13 children matched for age, sex and heart rate (10.4 +/- 3 years). All patients underwent 24-hour Holter monitoring. The following time domain indexes were calculated: mean duration of RR intervals, standard deviation of all RR intervals (SD), square root of the mean squared differences of successive RR intervals (r-MSSD), percentage of differences between adjacent RR intervals > 50 msec (pNN50). The following frequency domain indexes were calculated: total power (TP), low frequency (LF), high frequency (HF), LF/HF ratio. RESULTS: The following indexes were significantly reduced in Fontan patients: SD (p < 0.0001), r-MSSD (p < 0.0001), pNN50 (p = 0.0002), TP (p < 0.0001), LF (p < 0.0001), HF (p = 0.0001). LF/HF increased significantly (p = 0.04). No differences were detected according to the type of operation (cavopulmonary connection vs atriopulmonary connection) or clinical status. CONCLUSIONS: Patients with Fontan circulation had a significantly reduced HRV and particularly abnormal sympatho-vagal balance. Surgery on the caval veins and the atria alters the intracardiac ganglia that are abundant at the cavo-atrial junction and in the myocardium of the right atrium. Abnormalities of HRV in Fontan patients may act as a co-factor in the initiation of arrhythmia in these patients.     

Patients Operated for Tetralogy of Fallot and with Non-Sustained Ventricular Tachycardia Have Reduced Heart Rate Variability

BACKGROUND: To study heart rate variability (HRV) in patients operated for tetralogy of Fallot (ToF) and to identify any correlation between HRV and ventricular tachycardia (VT). PATIENTS AND METHODS: We studied HRV in 23 consecutive patients operated for ToF (mean age 14 +/- 6.6 years; mean follow-up 10.6 +/- 5.2 years). Seven patients had non-sustained VT on Holter monitoring. Two control groups were included: 18 healthy subjects and 15 patients operated for other congenital heart disease. There were no differences in age, age at surgery (in the operated groups), follow-up, and mean heart rate between the three groups. Four time and four frequency domain indices were calculated: mean duration of RR intervals, standard deviation of all RR intervals (SD), square root of the mean squared differences of successive RR intervals (r-MSSD), percent of differences between adjacent RR intervals (pNN50), total power (TP), low frequency (LF), high frequency (HF), and LF/HF ratio. RESULTS: HRV indices were identical in the two control groups but were significantly reduced in patients with ToF. Within the patients who had been operated on for ToF, HRV indices were significantly lower in the seven with non-sustained VT than in those without arrhythmias: SD (95 +/- 15 vs. 135 +/- 54 ms; p = 0.01), r-MSSD (26 +/- 9 vs. 45 +/- 20 ms; p = 0.03), pNN50 (4.4 +/- 3.4 vs. 16.5 +/- 12.5%; p = 0.001) and HF (111 +/- 97 vs. 352 +/- 291 ms(2); p = 0.009). Using stepwise multivariate regression analysis, pNN50, age at surgery, degree of pulmonary regurgitation and higher right/left ventricular ratio were independent predictive variables for VT (p < 0.0001; r(2) = 0.85). CONCLUSIONS: ToF patients, particularly those with ventricular arrhythmias, have significant impairment of sympatho-vagal balance, characterized by a reduction of vagal drive.