On the basis of Poincare scatter plot and first order difference scatter plot, a novel heart rate variability (HRV) analysis method based on scatter plots of RR intervals and first order difference of RR intervals (namely, RdR) was proposed. The abscissa of the RdR scatter plot, the x-axis, is RR intervals and the ordinate, y-axis, is the difference between successive RR intervals. The RdR scatter plot includes the information of RR intervals and the difference between successive RR intervals, which captures more HRV information. By RdR scatter plot analysis of some records of MIT-BIH arrhythmias database, we found that the scatter plot of uncoupled premature ventricular contraction (PVC), coupled ventricular bigeminy and ventricular trigeminy PVC had specific graphic characteristics. The RdR scatter plot method has higher detecting performance than the Poincare scatter plot method, and simpler and more intuitive than the first order difference method.
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.
目的:研究老年患者依托咪酯靶控输注时不同BIS值(脑电双频指数)的HRV(心率变异性)的变化情况,探讨不同镇静深度与HRV之间的关系。方法:选择65岁以上行门诊胃镜检查患者30例,随机分为3组,A组BIS45~55,B组55~65,C组65~75,各组均在麻醉前、麻醉诱导后,术中、术毕监测BIS、HRV及血液动力学指标。结果:A组各监测HRV明显降低(Plt;0.05),B组仅有轻度下降(Pgt;0.05),C组明显升高(Plt;0.05)。结论:患者镇静深度BIS55~65时,即可明显抑制内镜操作刺激所致的HRV变化,是临床较为合适的镇静深度,可显著降低老年患者交感神经活性、交感/迷走神经均衡性和自主神经总张力,利于机体血液动力学稳定。
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.
ObjectiveTo explore the predictive value of systolic pulmonary artery pressure (SPAP) on autonomic nerve excitation in patients with valvular disease, so as to provide reference for the formulation of clinical intervention plans. Methods The clinical data of patients with valvular disease who received surgical treatment in the General Hospital of Northern Theater Command from August 28, 2020 to February 3, 2021 were prospectively collected. According to the standard deviation of normal-to-normal R-R intervals (SDNN) of the heart rate variability (HRV) of the long-range dynamic electrocardiogram (ECG) 7 days before the operation, the patients were divided into three groups: a sympathetic dominant (SE) group (SDNN≤50 ms), a balance group (50 ms<SDNN<100 ms) and a parasympathetic dominant (PSE) group (SDNN≥100 ms). The correlation between the changes of echocardiographic indexes and autonomic nerve excitation among the groups and the predictive values were analyzed. Results A total of 186 patients were enrolled, including 108 males and 78 females aged 55.92±11.99 years. There were 26 patients in the SE group, 104 patients in the balance group, and 56 patients in the PSE group. The left anteroposterior diameter (LAD), left ventricular end diastolic inner diameter, ratio of peak E to peak A of mitral valve (Em/Am), left ventricular end diastolic volume, left ventricular end systolic volume and SPAP in the SE group were higher than those in the balance group (P<0.05), while peak A of tricuspid valve (At) and left ventricular ejection fraction (LVEF) were lower than those in the balance group (P<0.05). The LAD and Em/Am in the balance group were significantly higher than those in the PSE group (P<0.05). Multivariate analysis showed that patients in the SE group had lower At (right atrial systolic function declines), lower LVEF and higher SPAP than those in the balance group (P=0.04, 0.04 and 0.00). When HRV increased and parasympathetic nerve was excited in patients with valvular disease, Em/Am decreased (left atrial function and/or left ventricular diastolic function declined) with a normal LAD. Pearson analysis showed that there was a linear negative correlation between SPAP and SDNN, with a coefficient of −0.348, indicating that the higher SPAP, the lower HRV and the more excited sympathetic nerve. Receiver operating characteristic curve showed that when SPAP≥45.50 mm Hg (1 mm Hg=0.133 kPa), the sensitivity and specificity of sympathetic excitation in patients with valvular disease were 84.60% and 63.70%, respectively. ConclusionParasympathetic excitation is an early manifestation of the disease, often accompanied by decreased left atrial function and/or left ventricular diastolic function. Sympathetic nerve excitation can be accompanied by the increase of SPAP and the decrease of left ventricular and right atrial systolic function. SPAP has a unique predictive value for the prediction of autonomic nerve excitation in patients with valvular disease.
Heart rate variability (HRV) is the difference between the successive changes in the heartbeat cycle, and it is produced in the autonomic nervous system modulation of the sinus node of the heart. The HRV is a valuable indicator in predicting the sudden cardiac death and arrhythmic events. Traditional analysis of HRV is based on a multi-electrocardiogram (ECG), but the ECG signal acquisition is complex, so we have designed an HRV analysis system based on photoplethysmography (PPG). PPG signal is collected by a microcontroller from human’s finger, and it is sent to the terminal via USB-Serial module. The terminal software not only collects the data and plot waveforms, but also stores the data for future HRV analysis. The system is small in size, low in power consumption, and easy for operation. It is suitable for daily care no matter whether it is used at home or in a hospital.
Calculation of linear parameters, such as time-domain and frequency-domain analysis of heart rate variability (HRV), is a conventional method for assessment of autonomic nervous system activity. Nonlinear phenomena are certainly involved in the genesis of HRV. In a seemingly random signal the Poincaré plot can easily demonstrate whether there is an underlying determinism in the signal. Linear and nonlinear analysis methods were applied in the computer words inputting experiments in this study for physiological measurement. This study therefore demonstrated that Poincaré plot was a simple but powerful graphical tool to describe the dynamics of a system.
ObjectiveTo investigate the correlation between intima-media thickness (IMT) of carotid artery in color ultrasonography and the heart rate variability. MethodsA retrospective analysis was performed in 64 patients from West China Hospital of Sichuan University between March and May 2013. Carotid intima-media thickness was measured with color ultrasonography and dynamic electrocardiogram, and the heart rate variability was assayed at the same time. ResultsIMT in the cardiovascular disease group, combination group, coronary heart disease group and hypertension group was significantly thicker than the control group (P<0.05). The differences of SDNN and SDANN were statistically significant (P<0.05) between the combination group and the control group. There were 23 cases with IMT ≥ 1.0 mm in the cardiovascular disease group including 8 cases in the combination group, 10 cases in the coronary heart disease group and 5 cases in the hypertension group. IMT in those groups were all significantly higher than that in the control group with only 2 cases having IMT ≥ 1.0 mm (P<0.05). There were 18 cases with SDNN<100 ms in the cardiovascular disease group including 7 cases in the combination group, 6 cases in the coronary heart disease group and 5 cases in the hypertension group, but there was no statistically significant difference compared with that in the control group with only 11 cases (P>0.05). Negative correlation was found between IMT and SDNN, SDANN in the cardiovascular diseases group (r=-0.574, -0.544; P<0.01) and negative correlation was found between IMT and SDANN in the control group (r=-0.392, P<0.05). ConclusionThe carotid artery lesions and autonomic nerve especially sympathetic nerve dysfunction are obvious in patients with cardiovascular diseases and there is a negative correlation between them.
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.