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1.
目的:分析多层螺旋CT检测慢性阻塞性肺疾病患者肺容积指数的准确性,探讨多层螺旋CT 的诊断价值,为慢性阻塞性肺 病的临床诊断提供可借鉴的方法。方法:选取2010 年10 月-2012 年8月我院收治的慢性阻塞性肺疾病患者98例为观察组,另选 取同期接受体检的健康志愿者70 例为对照组。采用多层螺旋CT 测定两组不同肺区的肺容积指标并与临床PFT 指标进行相关 性分析。结果:对照组与观察组的肺功能指标存在显著差异(P<0.05);观察组患者在不同肺区测定的Vin 及上肺区Vin-Vex 值无 统计学意义(P>0.05);最大呼气末容积(Vex)、容积比(Vex/Vin)和肺容积变化比率[(Vin-Vex)/Vin]均呈显著差异,具有统计学意义 (P<0.05);肺容积差(Vin-Vex)与各项PFT 指标无相关性(P>0.05)。结论:64层螺旋CT 肺容积成像对诊断COPD有预测意义,值得 临床上进一步研究和推广。  相似文献   

2.
本工作的目的是研究急性高原低氧对豚鼠听觉传入功能的影响。20只豚鼠分为4组,分别接受模拟海拔高度为5000、6000、7000和800om的急性低氧暴露,于不同时间测定听觉脑干诱发反应各波的潜伏期、峰间期、振幅和III波的电反应阈(听阈)。结果如下:当升至预定的海拔高度和在低氧维持阶段,6000m以上组各波潜伏期延长,其中II波变化更明显;回到海平面高度后逐渐恢复,1h内基本可恢复正常;潜伏期变化的程度与海拔高度有关。在低氧阶段各波振幅普遍下降,回到海平面高度后逐渐回升,但恢复至正常所需时间较长。在升至预定的海拔高度和其后低氧维持阶段,各组动物的听阈均上升,脱离低氧后即可迅速恢复,1h内可恢复正常。结果表明,急性高原低氧使听觉脑干传导时间延长,传入神经元兴奋性降低,听敏度下降,因而可以推测它能影响声信号的传入。  相似文献   

3.
目的:分析多层螺旋CT检测慢性阻塞性肺疾病患者肺容积指数的准确性,探讨多层螺旋CT的诊断价值,为慢性阻塞性肺病的临床诊断提供可借鉴的方法。方法:选取2010年10月-2012年8月我院收治的慢性阻塞性肺疾病患者98例为观察组,另选取同期接受体检的健康志愿者70例为对照组。采用多层螺旋CT测定两组不同肺区的肺容积指标并与临床PFT指标进行相关性分析。结果:对照组与观察组的肺功能指标存在显著差异(P〈0.05);观察组患者在不同肺区测定的Vin及上肺区Vin-Vex值无统计学意义(P〉0.05);最大呼气末容积(Vex)、容积比(Vex/Vin)和肺容积变化比率[(Vin-Vex)/Vin]均呈显著差异,具有统计学意义(P〈0.05);肺容积差(Vin-Vex)与各项PFT指标无相关性(P〉0.05)。结论:64层螺旋CT肺容积成像对诊断COPD有预测意义,值得临床上进一步研究和推广。  相似文献   

4.
目的对比格犬、恒河猴、日本大耳白兔、树鼩四个不同种属实验动物的ECG-II进行分析比较,归纳其ECG-II的特点,旨在为上述动物在安评中的运用提供参考。方法选择成年比格犬、恒河猴、日本大耳白和树鼩,分别对其在清醒状态下的ECG-II进行描记和分析,并对ECG-II各项指标进行测量分析。结果与结论不同种属动物均为窦性心律,在波型方面基本一致,未出现特异性改变,但不同动物在QRS波群和T波形态上具有一定差异;各指标测定结果显示,日本大耳白兔P波、T波振幅和树鼩心率分别小于和快于其他种属动物。  相似文献   

5.
目的:探讨烟龄215年,日吸烟量≥15支的无症状男性吸烟者的肺功能改变情况。方法:选择男性无症状吸烟者190人及非吸烟者180人,进行肺功能测定,并比较两组人群的肺功能改变情况。结果:吸烟组与非吸烟组比较,肺活量(VC)、用力肺活量(FVC)、第1秒用力呼气容积(FEV1)、Tiffeneau1秒率(FEV1/VC)结果改变不明显,而Gaensler1秒率(FEV1/FVC)、最大分钟通气量(MVV)、用力呼气50%肺活量的呼气流量(FEF50%)、用力呼气75%肺活量的呼气流量(FEF75%)、呼出25%-75%肺活量时的平均流量(FEF25%~75%)、肺一氧化碳弥散量(DLCO)结果均有显著降低,有统计学意义。结论:通过对无症状吸烟人群肺功能测定结果进行分析。发现有些吸烟者虽无临床症状,但已经出现了小气道及肺弥散功能的损伤,提醒吸烟者应早期戒烟,关爱自身健康,净化生存环境,提高生活质量。  相似文献   

6.
犬心肌缺血再灌注损伤心电图Ⅱ导联QRS波群的演变   总被引:2,自引:0,他引:2  
目的观察杂种犬心肌缺血再灌注损伤过程心电图(ECG)的动态变化规律,为研究干细胞移植对犬心肌缺血再灌注损伤后的治疗作用提供基础。方法选用杂种犬24只,结扎冠状动脉左前降支中远1/3处,分3组分别于30min、60min、90min后松开。应用MPA-2000生物信号分析系统,在结扎前后及松开后连续动态记录ECGII导联QRS波群的变化。结果在开始结扎阻断冠状动脉血流时,QRS主波向上Rs型;重新开放血流血管再通之初,83.3%(20/24)的犬QRS波表现为主波向下rS型或QS型,伴QRS波增宽,然后r波波幅逐渐增大,逐渐演变成主波向上的Rs型,QRS时程恢复正常。15min、30min和大于30min的演变率分别为25.00%(6/24)、41.7%(10/24)和16.7%(4/24);且演变率与冠脉阻断时间相关。结论犬心肌缺血再灌注后ECG变化有一定规律,QRS波群变化趋势有可能作为心肌细胞功能恢复程度以及心肌保护效果较为直观的判断指标。  相似文献   

7.
本文用心电图记录离体豚鼠灌流心脏。提高灌流液中钙的浓度(由2.5分别提高到4.0、6.0、8.0和10.0mEq/L),导致全部的 Ta 波振幅降低,P—aTa 间期缩短。Ta 波的形态由正常时的“帐蓬形’变为“钝角形”。然而,降低灌流液中钙的浓度(由2.5降至2.0、1.2和0mEq/L)引起的相反变化,即 Ta 波振幅增加和 P—aTa 间期延长。另一方面,降低灌流液中钠的浓度(由143分别降至133、123和113mEq/L)出现 Ta 波振幅降低,但当提高灌流液中钠浓度时,所观察标本仅50%出现 Ta 波振幅升高。这提示,豚鼠心房肌对高钠浓度不如对低钠浓度敏感。T 波的变化可能是由于钠浓度改变的结果。  相似文献   

8.
为研究噪声作用后听觉中枢诱发反应振幅变化,用豚鼠记录了器材怕作用前后皮层诱发反应(ACER)和脑干诱发反应(ABR)的振幅和潜伏期,比较了暴露噪声前后短声刺激系列强度中ACER和ABR最大振幅和潜伏期,110dBA宽带噪声作用30分钟后,听阈提高53dB,ACER最大振幅增大24%,1小时后仍为24%,2小时后增大28%,峰间潜伏期(P1-P2)比暴露前缩短,噪声作用后ABRV波最大振幅增大15%,1小时后为21%,2小时后为28%,潜伏期比暴露前缩短,AP、ABP、Ⅰ、Ⅲ。Ⅳ波最大振幅均经暴露前减小。结果表明,强噪声作用后ACER存在振幅增大,同时ABRV波也有振幅增大现象。  相似文献   

9.
本文综述了QRS波群自动分类技术的关键技术及其研究方向,内容涉及QRS波群的描述方法、分类方法和训练数据集这三个重要影响因素。  相似文献   

10.
本实验应用拟合法观察了高频喷射通气时组胺致肺损伤犬的呼吸力学改变。结果表明,静脉持续滴注组胺后,跨肺压、气道压明显升高;呼气相肺顺应性及呼吸系统总顺应性分别由对照值0.727±0.168和0.344±0.077降到0.336±0.102和0.195±0.036L·kPa~(-1)(P<0.05),肺阻力和呼吸系统总阻力分别由对照值0.091±0.021和0.211±0.045升至0.191±0.024和0.362±0.049kPa·L~(-1)·s~(-1)(P<0.05);吸气相肺及呼吸系统顺应性、阻力的变化均未达显著水平。组胺滴注前、后呼气相呼吸系统顺应性与肺顺应性均呈显著正相关。我们认为,高频喷射通气时应用曲线拟合法实时监测组胺致肺损伤犬的呼吸力学变化是可行的,监测呼气相呼吸系统顺应性可用作无创、间接测量肺顺应性。  相似文献   

11.
基于对QRS波群的特征变量提取。利用减法聚类和自适应模糊神经网络构建心律失常辅助诊断模型,分析不同训练数据集对模型测试结果的影响。实验结果表明。该模型能准确识别不同类型的QRS波群,使用不同训练数据集对诊断结果存在影响,为进一步实现更复杂的心律失常辅助诊断模型提供方法。  相似文献   

12.
Fragment QRS (fQRS) complex is a myocardial conduction abnormality that indicates myocardial scar. It is defined as additional notches in the QRS complex. Though initially fQRS was defined in the setting of normal QRS duration (<120 m s), later it has been expanded to include conditions with wide QRS complexes as in bundle branch block, ventricular ectopy and paced rhythm, when more than 2 notches are present. It is an important, yet often overlooked marker of mortality and arrhythmic events in many cardiac diseases. The significance of fQRS lies in the fact that it just requires a surface ECG for its recording and the value of information about the condition of the heart it dispenses based on the clinical setting. We review the role of fQRS in predicting adverse cardiac events in various conditions.  相似文献   

13.
Human glutaminyl-tRNA synthetase (QRS) is one of several mammalian aminoacyl-tRNA synthetases (ARSs) that form a macromolecular protein complex. To understand the mechanism of QRS targeting to the multi-ARS complex, we analyzed both exogenous and endogenous QRSs by immunoprecipitation after overexpression of various Myc-tagged QRS mutants in human embryonic kidney 293 cells. Whereas a deletion mutant containing only the catalytic domain (QRS-C) was targeted to the multi-ARS complex, a mutant QRS containing only the N-terminal appended domain (QRS-N) was not. Deletion mapping showed that the ATP-binding Rossman fold was necessary for targeting of QRS to the multi-ARS complex. Furthermore, exogenous Myc-tagged QRS-C was co-immunoprecipitated with endogenous QRS. Since glutaminylation of tRNA was dramatically increased in cells transfected with the full-length QRS, but not with either QRS-C or QRS-N, both the QRS catalytic domain and the N-terminal appended domain were required for full aminoacylation activity. When QRS-C was overexpressed, arginyl-tRNA synthetase and p43 were released from the multi-ARS complex along with endogenous QRS, suggesting that the N-terminal appendix of QRS is required to keep arginyl-tRNA synthetase and p43 within the complex. Thus, the eukaryote-specific N-terminal appendix of QRS appears to stabilize the association of other components in the multi-ARS complex, whereas the C-terminal catalytic domain is necessary for QRS association with the multi-ARS complex.  相似文献   

14.
In this paper, a new method for QRS complex analysis and estimation based on principal component analysis (PCA) and polynomial fitting techniques is presented. Multi-channel ECG signals were recorded and QRS complexes were obtained from every channel and aligned perfectly in matrices. For every channel, the covariance matrix was calculated from the QRS complex data matrix of many heartbeats. Then the corresponding eigenvectors and eigenvalues were calculated and reconstruction parameter vectors were computed by expansion of every beat in terms of the principal eigenvectors. These parameter vectors show short-term fluctuations that have to be discriminated from abrupt changes or long-term trends that might indicate diseases. For this purpose, first-order poly-fit methods were applied to the elements of the reconstruction parameter vectors. In healthy volunteers, subsequent QRS complexes were estimated by calculating the corresponding reconstruction parameter vectors derived from these functions. The similarity, absolute error and RMS error between the original and predicted QRS complexes were measured. Based on this work, thresholds can be defined for changes in the parameter vectors that indicate diseases.  相似文献   

15.
The aphid Pemphigus betae typically shows a complex life cycle, with annual alternation between cottonwood trees, where it forms leaf galls, and herbaceous plants, where it lives on roots. Distinct phenotypes are associated with each phase. In a population in Utah, aphid clones vary in their tendencies to undergo the cottonwood phase of the life cycle, with certain clones rarely producing the winged migrants that initiate the cottonwood phase. To examine the extent of genotypic variability in life cycle traits and to determine the consequences of phase deletion for fitness in the remaining phase of the life cycle, I compared performances of sets of clones that differed in their tendencies to delete the cottonwood phase. Performances of 35 aphid clones were compared on root hosts in the laboratory, by quantifying size (a correlate of fecundity), developmental time, and mortality for clonal sublines. Clones that tend to delete the cottonwood phase and remain on roots developed faster, showed lower mortality, and were larger as compared to clones that tend to undergo an annual migration to cottonwood. These laboratory comparisons of individual clones agree with earlier findings from field experiments. Performance also varied significantly among clones within sets, with the set of clones not previously subjected to selection on root hosts showing higher variance than clones isolated following selection in the root-inhabiting phase. These data suggest that selection in the cottonwood phase opposes selection in the root phase. Thus, even in cases of polyphenism, in which divergent developmental pathways confer some independence of phenotypic expression in alternative phases, antagonistic pleiotropy limits adaptation within a phase. These findings on the correlates of intrapopulational variation in frequency of phase expression provide some of the best evidence for character release following reduction of a complex life cycle, and they support the hypothesis that the advantages of polyphenism may be limited by negative genetic correlations among fitness traits of alternative phenotypes.  相似文献   

16.
QRS波群是ECG信号的重要组成部分,是心电信号分析的基础.QRS波群的检测方法已经有很多种实用有效的方法,并逐步地走向成熟,在实际应用中得到实现.本文就QRS波群的检测方法作了具体的整理与分析,较全面的阐述了实际应用中的各种算法,最后作者对检测算法的发展趋势进行了总结和展望.  相似文献   

17.
《IRBM》2019,40(3):157-166
ObjectiveFetal Electro Cardiogram (fECG) provides critical information on the wellbeing of a foetus heart in its developing stages in the mother's womb. The objective of this work is to extract fECG which is buried in a composite signal consisting of itself, maternal ECG (mECG) and noises contributed from various unavoidable sources. In the past, the challenge of extracting fECG from the composite signal was dealt with by Stochastic Weiner filter, model-based Kalman filter and other adaptive filtering techniques. Blind Source Separation (BSS) based Independent Component Analysis (ICA) has shown an edge over the adaptive filtering techniques as the former does not require a reference signal. Recently, data-driven machine learning techniques e.g., adaptive neural networks, adaptive neuro-fuzzy inference system, support vector machine (SVM) are also applied.MethodThis work pursues hidden Markov model (HMM)-based supervised machine learning frame-work for the determination of the location of fECG QRS complex from the composite abdominal signal. HMM is used to model the underlying hidden states of the observable time series of the extracted and separated fECG data with its QRS peak location as one of the hidden states. The state transition probabilities are estimated in the training phase using the annotated data sets. Afterwards, using the estimated HMM networks, fQRS locations are detected in the testing phase. To evaluate the proposed technique, the accuracy of the correct detection of QRS complex with respect to the correct annotation of QRS complex location is considered and quantified by the sensitivity, probability of false alarm, and accuracy.ResultsThe best results that have been achieved using the proposed method are: accuracy – 97.1%, correct detection rate (translated to sensitivity) – 100%, and false alarm rate – 2.89%.ConclusionTwo primary challenges in these methods are finding the right reference threshold for the normalization of the extracted fECG signal during the initial trials and limitation of discrete frame work of HMM signal (converted from continuous time) which only offers a countable number of levels in observations. By feeding the posterior probabilities, obtained from SVM, into HMM, as emission probabilities, can further improve the accuracy of fQRS location detection.  相似文献   

18.
Aberrant ventricular conduction is a rare phenomenon as compared with the more frequently occurring antrioventricular conduction disturbances. It leads to widening of the QRS complex, which is either due to a complete or functional block in one of the bundle branches or a block within the intramyocardial conduction system itself. Mechanisms that are potentially involved in the genesis of aberrant ventricular conduction are sudden shortening of cycle length (tachycardia-dependent phase III), antegrade block with retrograde concealed conduction, or bradycardia-dependent block (enhanced phase IV). In this paper, we present a patient with aberrant ventricular conduction with the occurrence of a tachycardia-dependent, as well as a bradycardia-dependent bundle branch block, which is an even rarer phenomenon.  相似文献   

19.
Fluctuation energy of spectral analysis containing ECG signals were studied in 17 experiments before the modeling of fast death. In the early period of resuscitation ECG recordings were done in 13 orthogonal leads (Frank method). On each lead 5 cardiac cycles were registered with the analysis of 2 components of the ECG: complex QRS and T-wave. In the analyzed period the phase changes for coefficient fluctuations were established. The authors express supposition, that the low meaning of coefficient fluctuations appear in the process of compensation, but high meanings--just like an explosion of compensation.  相似文献   

20.
Cardiovascular diseases are the number one cause of death worldwide. Currently, portable battery-operated systems such as mobile phones with wireless ECG sensors have the potential to be used in continuous cardiac function assessment that can be easily integrated into daily life. These portable point-of-care diagnostic systems can therefore help unveil and treat cardiovascular diseases. The basis for ECG analysis is a robust detection of the prominent QRS complex, as well as other ECG signal characteristics. However, it is not clear from the literature which ECG analysis algorithms are suited for an implementation on a mobile device. We investigate current QRS detection algorithms based on three assessment criteria: 1) robustness to noise, 2) parameter choice, and 3) numerical efficiency, in order to target a universal fast-robust detector. Furthermore, existing QRS detection algorithms may provide an acceptable solution only on small segments of ECG signals, within a certain amplitude range, or amid particular types of arrhythmia and/or noise. These issues are discussed in the context of a comparison with the most conventional algorithms, followed by future recommendations for developing reliable QRS detection schemes suitable for implementation on battery-operated mobile devices.  相似文献   

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