Objective To investigate the changes and clinical relationship of plasma adrenomedullin( ADM) , atrial natriuretic polypeptide( ANP) , and heart rate variability( HRV) in patients with obstructive sleep apnea-hypopnea syndrome ( OSAHS) . Methods Seventy-five inpatients with OSAHS were enrolled in this study. According to the apnea hypopnea index ( AHI) by polysomnography, the subjects were divided into a mild group, a moderate group, and a severe group. Meanwhile, HRV was screened bydynamic electrocardiogram in sleep laboratory. HRV parameters were obtained including LF ( low frequency power) , HF( high frequency power) , pNN50( percentage of NN50 in the total number of N-N intervals) ,SDNN( standard deviation of the N-N intervals) , rMSSD( square root of the mean squared differences of successive N-N intervals ) . Plasma levels of ADM/ANP were measured by radioimmunoassay. Results The levels of SDNN ( P lt;0. 05) , rMSSD, pNN50, LF ( P lt; 0. 05) and HF were gradually reduced, and the levels of ADM ( P lt;0. 05) and ANP ( P lt; 0. 05) were increased with increasing severity of OSAHS. Linear correlation analysis demonstrated that SDNN was negatively correlated with ADM( r = - 0. 423, P lt;0. 05)and ANP( r = - 0. 452, P lt; 0. 05) , and LF was also negatively correlated with ADM( r = - 0. 348, P lt;0. 05) . Conclusion Lower HRV is associated with more sever OSAHS, and it may be modulated neurohumorally by ADM and ANP.
ObjectiveTo study the relationship between preoperative heart rate variability (HRV) and postoperative atrial fibrillation (POAF) after off-pump coronary artery bypass grafting (OPCAB). MethodsA retrospective analysis was performed on the clinical data of 290 patients who were admitted to the Department of Cardiovascular Surgery, General Hospital of Northern Theater Command from May to September 2020 and received OPCAB. There were 217 males and 73 females aged 36-80 years. According to the incidence of POAF, the patients were divided into two groups: a non-atrial fibrillation group (208 patients) and an atrial fibrillation group (82 patients). The time domain and frequency domain factors of mean HRV 7 days before operation were calculated: standard deviation of all normal-to-normal intervals (SDNN), root mean square of successive differences, percentage difference between adjacent normal-to-normal intervals that were greater than 50 ms, low frequency power (LF), high frequency power (HF), LF/HF. ResultsThe HRV value of patients without POAF was significantly lower than that of patients with POAF (P<0.05). The median SDNN of the two groups were 78.90 ms and 91.55 ms, respectively. Age (OR=3.630, 95%CI 2.015-6.542, P<0.001), left atrial diameter (OR=1.074, 95%CI 1.000-1.155, P=0.046), and SDNN (OR=1.017, 95%CI 1.002-1.032, P=0.024) were independently associated with the risk of POPAF after OPCAB. Conclusion SDNN may be an independent predictor of POAF after OPCAB.
Lorenz plot (LP) method which gives a global view of long-time electrocardiogram signals, is an efficient simple visualization tool to analyze cardiac arrhythmias, and the morphologies and positions of the extracted attractors may reveal the underlying mechanisms of the onset and termination of arrhythmias. But automatic diagnosis is still impossible because it is lack of the method of extracting attractors by now. We presented here a methodology of attractor extraction and recognition based upon homogeneously statistical properties of the location parameters of scatter points in three dimensional LP (3DLP), which was constructed by three successive RR intervals as X, Y and Z axis in Cartesian coordinate system. Validation experiments were tested in a group of RR-interval time series and tags data with frequent unifocal premature complexes exported from a 24-hour Holter system. The results showed that this method had excellent effective not only on extraction of attractors, but also on automatic recognition of attractors by the location parameters such as the azimuth of the points peak frequency (APF) of eccentric attractors once stereographic projection of 3DLP along the space diagonal. Besides, APF was still a powerful index of differential diagnosis of atrial and ventricular extrasystole. Additional experiments proved that this method was also available on several other arrhythmias. Moreover, there were extremely relevant relationships between 3DLP and two dimensional LPs which indicate any conventional achievement of LPs could be implanted into 3DLP. It would have a broad application prospect to integrate this method into conventional long-time electrocardiogram monitoring and analysis system.
目的:了解阻塞性睡眠呼吸暂停综合征患者的心率变异改变。方法:对67例睡眠打鼾患者同步进行24小时动态心电图及多导睡眠图监测。根据PSG检测结果分为OSAS组和单纯鼾症组,比较组间低频峰(LF),高频峰(HF),低频峰与高频峰的比值(LF/HF),正常RR间期平均值及其标准差值(SDNN),正常RR间期差值均方根(rMSSD)。结果:OSAS组中,频域分析指标:LF,HF,均低于单纯鼾症组,LF/HF高于对照组,时域分析指标:SDNN,rMSSD均低于对照组。结论:OSAHS患者心率变异性降低。
Heart rate variability (HRV) is an important point to judge a person’s state in modern medicine. This paper is aimed to research a person’s fatigue level connected with vagal nerve based on the HRV using the improved Welch method. The process of this method is that it firstly uses a time window function on the signal to be processed, then sets the length of time according to the requirement, and finally makes frequency domain analysis. Compared with classical periodogram method, the variance and consistency of the present method have been improved. We can set time span freely using this method (at present, the time of international standard to measure HRV is 5 minutes). This paper analyses the HRV’s characteristics of fatigue crowd based on the database provided by PhysioNet. We therefore draw the conclusion that the accuracy of Welch analyzing HRV combining with appropriate window function has been improved enormously, and when the person changes to fatigue, the vagal activity is diminished and sympathetic activity is raised.
Heart rate is the most common index to directly monitor the level of physical stress by comparing the subject's heart rate with an appropriate "target heart rate" during exercise. However, heart rate only reveals the cardiac rhythm of the complex cardiovascular changes that take place during exercise. It is essential to get the dynamic response of the heart to exercise with various indices instead of only one single measurement. Based on the rest-workload alternating pattern, this paper screens the sensitive indices of exercise load from electrocardiogram (ECG) rhythm and waveform, including 4 time domain indices and 4 frequency domain indices of heart rate variability (HRV), 3 indices of waveform similarity and 2 indices of high frequency noise. In conclusion, RR interval (heart rate) is a reliable index for the realtime monitoring of exercise intensity, which has strong linear correlation with load intensity. The ECG waveform similarity and HRV indices are useful for the evaluation of exercise load.
【摘要】 目的 探讨急性脑梗死对心脏自主神经活性的影响。 方法 Wistar大鼠32只随机分为正常组、假手术组和脑梗死组，脑梗死组用线栓法行右侧大脑中动脉阻塞。脑梗死组和假手术组于术前及术后24 h作心率变异性（HRV）检测，同时检测正常组HRV，将3组的HRV指标进行比较。实验终点取各组心肌组织检测儿茶酚胺和神经肽Y（NPY），进行组间比较。 结果 术后24 h脑梗死组和正常组、假手术组相比，窦性心搏间期标准差、均方根，总功率谱、高频功率谱（HF）、低频功率谱（LF）降低，差异有统计学意义。3组比较LF/HF和分数维无明显差异。脑梗死组心肌组织去甲肾上腺素（NA）和NPY高于正常组和假手术组。 结论 脑梗死引起心脏自主神经总活性降低、自主神经功能受损，自主神经末梢去甲肾上腺素和NPY的异常分泌可能是重要的原因。【Abstract】 Objective To investigate the effect of acute cerebral infarction on cardiac autonomic nervous activity. Methods A total of 32 Wistar rats were divided into normal group, sham operation group and infarction group by random. Experimental cerebral infarction in Wistar rats was induced by intraluminal occlusion of middle cerebral artery. About 24 hours after the occlusion or 24 hours after sham operation, the heart rate variability (HRV) sequences were measured, and the HRV values in the three groups were compared. The levels of catecholamine and neuropeptide (NPY) in myocardium were measured. Results At the 24th hour after the occlusion, the standard deviation and root mean square standard deviation of R-R interval, the total power, high frequency (HF) and low frequency (LF) in infarction group were lower than those in normal and sham operation group. LF/HF and fractal dimension did not differ much among the three groups. The levels of noradrenaline and NPY in myocardium in infarction group were higher than those in the other groups. Conclusion It is suggested that acute cerebral infarction may cause the decrease of autonomic nervous activity and damage of the autonomic nervous function; the abnormal secretion of noradrenalin in autonomic nerve ending and NPY may be the important reasons.
Sleep status is an important indicator to evaluate the health status of human beings. In this paper, we proposed a novel type of unperturbed sleep monitoring system under pillow to identify the pattern change of heart rate variability (HRV) through obtained RR interval signal, and to calculate the corresponding sleep stages combined with hidden Markov model (HMM) under the no-perception condition. In order to solve the existing problems of sleep staging based on HMM, ensemble empirical mode decomposition (EEMD) was proposed to eliminate the error caused by the individual differences in HRV and then to calculate the corresponding sleep stages. Ten normal subjects of different age and gender without sleep disorders were selected from Guangzhou Institute of Respirator Diseases for heart rate monitoring. Comparing sleep stage results based on HMM to that of polysomnography (PSG), the experimental results validate that the proposed noninvasive monitoring system can capture the sleep stages S1–S4 with an accuracy more than 60%, and performs superior to that of the existing sleep staging scheme based on HMM.