基于连续小波变换的心电信号特征提取及其仪器实现

介绍了一种用于心电信号的记录和识别的虚拟式测量和分析仪器系统，目的是要构建一种基于PC的虚拟仪器．能够实现十二导联心电信号的同步记录、同步整体观察及测量12导联同一心动周期的波形，从而提高心电参数测量的准确性。同时，由于Mexican hat小波特有的时域特性，对QRS波群具有很好的定位特性和分析精度，因此在本仪器中利用连续小波变换，选用Mexicanhat作为小波基，对心电信号中的特征信息进行精确检测，并给出准确的心电信号特征描述参数。对临床实测心电信号的分析表明，即使在有严重噪声干扰的情况下，本方法也很容易实现对心电信号特征信息的精确描述，并且具有很高的实时性，从而在本仪器中获得了实际和有效的应用。     

高可靠度心率变异性信号获取的实验研究

心率变异性信号的获取在生理研究和临床诊断中都有着重要的应用价值。为了保证心率变异性分析的准确性，必须考虑心率变异性的获取方法。本文利用信号奇异点及其小波变换的关系，设计了HRV信号的R波获取软件。对MIT／BIH心电数据库中的37个记录文件进行R波的检测实验，检测实验效果令人满意。     

为美国宇航局设计的手提式生理参数监护仪

手提式生理参数监护仪是一种采用混台式集成电路技术的小型化装置。它能显示体温、心率、呼吸率。通过外电路的处理还能显示收缩压和舒张压。它的主要元件是液晶显示器,四道二端输入数字开关和六个新的混合电路,包括:体温监护器;心电放大器;阻抗呼吸描记器和呼吸率信号调节器;心率/呼吸率处理机;液晶显示激励器相同步脉冲电路。重新设计了通用电路,取消了大的电容器和电位计,并减少了定标调节的数量。提高了显示方式的适应性,各个电路都能独立应用于其他用途。从三个胸壁电极和一个温度监视热敏电阻引出信息输入到电路中去。胸壁电极信号同时馈送至心电放大器和呼吸信号调节器。在心电电路内的信号被放大、滤波并用来作为标准     

适用于智能听诊的心肺音、心电同步采集设备设计与研制

基于现有听诊器不具备心肺音、心电同时采集的功能,设计一款完备的新型双模心肺音、心电同步采集设备。采用精密微弱信号放大技术实现音频的无损放大,采用高输入阻抗设计实现心电的单电极采集,采用高保真SJR-BTM870-B蓝牙模块实现双模音频无损传输。最后实验结果表明,该研制设备具有重要的临床应用价值和科研价值。     

二维富里叶变换方法在逐搏心电图频率分量变异性分析中的 …

晚电位是在体表心电信号趴有高频分量的微弱信号（１￣２０μＶ），通常能在患有室性心动过速病人心电记录中观测到，这些信号的评估需要十分复杂的信号记录技术（对于单搏分析）或信号平均技术，然而，信号平均可能会掩盖风险信息，因此，发展了依赖于１２８个连续心搏中的８０ｍｓ数据段进行二维富里叶变换的单搏谱变异（ＳＢＳＶ），这个方法描述了这些心电片段频率成份的搏变异特性，一个参数函数使得对晚电位的客观探讨成为可能     

基于功率谱特征的心电数据小波压缩方法

利用心电功率谱特征,探索心电数据压缩新方法。用小波分解心电信号为高频与低频分量,对低频分量继续分解达到要求的级数,对高频分量则根据其所在频段的能量,对临床诊断的价值加以取舍。对MIT生理信号数据库心电数据的压缩与还原分析表明,该方法平衡了压缩比与还原精度之间的矛盾,既具有较高的压缩比,又具有较高的还原精度,而且对信号的适应性也明显增强。另外,该压缩方法还具有一定的去噪作用。说明结合心电功率谱特征与小波变换方法压缩心电有其优势。     

心电、呼吸信号采集分析系统的研制

设计一种用于移动监护系统的生理信息采集及预处理装置.该装置以ARM为核心,包括低功耗的双路心电信号放大、滤波、抗基线漂移电路.实现了心电信号的采集、预处理、简单分析及从心电信号中提取呼吸信号等功能.     

心电信息数据库系统开发

心原性猝死是严重威胁人类的第一大死亡原因，深入研究心脏猝死对于临床预后，降低总死亡率、提高生活质量，降低医疗保健费用有着重要的意义。本研究建立了一个具有1297条信号记录及其相应的临床信息，能够和当前国际上大型生理信号数据库进行软件和数据共享的心电信息数据库系统。该数据库的建立将促进心血管疾病尤其是心原性猝死的解释、诊断和预测。     

快采慢放—一种记录快变生理信号的新方法

快变生理信号的记录,在生物学、药理学和电生理学的研究中都具有很重要的意义.如人的高频心电波是新发展起来的一种心脏的附诊指标;实验小白鼠的快变心电图,对研究小白鼠的心血管功能状态有很大的意义.记录这些快变的生理信号,需要一种快变生理信号记录的设备.但用心电图机记录器无法清晰的记录这些快变的波形.本文叙述的新方法,采用单片机技术,应用快采慢放的原理,研制出一种能用心电图机记录器或普通记录器,记录快变生理信号的实用设备.此设备具有结构简单、成本低廉和应用方便的特点.为动物生理和药理实验增加了一种新的监测手段.     

无创伤性单次心搏心室迟电位的检测

一、导言采用无创方法检测微伏级心电信号首次于1973年被报导。当时Berbari等人及Flowers、Horan各自独立地报导了他们采用高放大倍数放大器与信号集平均技术检测到由狗的传导系统产生的电位信号。这种技术改善了受随机噪声污染的重复性信号的信噪比,从而用于检测人体希氏蒲肯     

Development and preliminary clinical tests of an impedance sensing VDD recording pacemaker for diagnosis and research

Episodes of serious but infrequently occurring cardiac arrhythmias can be difficult to detect and analyse, even with modern Holter monitoring. A previous diagnostic pacemaker developed by this group provided VVI pacing therapy and recorded intracardiac ECG signals but had no atrial sensing or impedance measuring capability. A new external diagnostic pacemaker system is described that has been developed to assist in diagnosing intermittent arrhythmias by selectively recording intracardiac signals. Unlike other ambulatory monitors, in addition to recording ECG, the device combines VDD pacing therapy with the capability of monitoring and recording intracardiac impedance and pressure waveforms through a temporary intracardiac lead. A PCMCIA memory card allows storage of 48 arrhythmic events of 21 seconds each. Twelve seconds of waveform are retained before the event occurs and nine seconds after. Data retrieval and processing is performed with a PC which reconstructs each waveform for display. The ECG provides data on cardiac rhythm while cardiac function is inferred from the haemodynamic signals. During simulated trials, 14 event types were presented to the system. All events were successfully detected and recorded. During in vivo clinical tests 83 waveform recordings were made. Impedance fluctuations with typical peak-to-peak values of 64 ohms were successfully recorded.     

Development and preliminary clinical tests of an impedance sensing VDD recording pacemaker for diagnosis and research

Episodes of serious but infrequently occurring cardiac arrhythmias can be difficult to detect and analyse, even with modern Holter monitoring. A previous diagnostic pacemaker developed by this group provided VVI pacing therapy and recorded intracardiac ECG signals but had no atrial sensing or impedance measuring capability. A new external diagnostic pacemaker system is described that has been developed to assist in diagnosing intermittent arrhythmias by selectively recording intracardiac signals. Unlike other ambulatory monitors, in addition to recording ECG, the device combines VDD pacing therapy with the capability of monitoring and recording intracardiac impedance and pressure waveforms through a temporary intracardiac lead. A PCMCIA memory card allows storage of 48 arrhythmic events of 21 seconds each. Twelve seconds of waveform are retained before the event occurs and nine seconds after. Data retrieval and processing is performed with a PC which reconstructs each waveform for display. The ECG provides data on cardiac rhythm while cardiac function is inferred from the haemodynamic signals. During simulated trials, 14 event types were presented to the system. All events were successfully detected and recorded. During in vivo clinical tests 83 waveform recordings were made. Impedance fluctuations with typical peak-to-peak values of 64 ohms were successfully recorded.     

床旁检测体表逐搏His束电图

目的 探讨体表逐搏检测His束电位在床旁的应用价值。方法 使用极低躁声三通道高增益放大器，16位A／D转换，通过USB接口与微机连接。应用数字滤波加模式识别软件对微信号进行处理。记录时受检取仰卧位。结果 38个志愿用逐搏体表His束检测仪清晰地记录到心房与心室之间的His束电活动，即A波、H波与V波。10例患体表检测与心内导管电极记录进行对照，2种方法获得的参数基本一致。结论 无创体表逐搏检测His束电活动有广泛临床价值，对心脏电生理研究和对房室传导阻滞的诊断有高度实用性。     

犬希氏束起搏的心脏电生理和血液动力学效应研究

目的:探讨希氏束起搏电极定位技术及心脏电生理和血液动力学变化特点。方法:健康犬在全麻呼吸机通气下,开胸,将特制希氏束(HisB)标测/起搏电极进行HisB电位标测,确定HisB起搏位点;并将心室起搏电极固定于右室尖部分别构成HisB-_VVI、RVA-_VVI单腔心脏起搏,对比分析其心脏电生理和血液动力学参数变化。结果:HisB起搏阈值参数符合心室起搏要求;HisB-_VVI起搏QRS波较RVA-_VVI起搏变窄;心输出量(CO)较自身增加18.81%,RVA-_VVI起搏反而降低约5.41%;每搏量(SV)接近于自身窦性心律,但明显高于RVA-_VVI起搏约25.59%;左室每搏功(LVSW)和右室每搏功(RVSW)等参数亦明显优于RVA-_VVI心脏起搏。结论:HisB起搏由于将心室起搏位点从传统的右室尖改为His束,从而保持了近于正常生理性心室激动顺序和心室收缩同步性,故可维持整个心脏协调有序的收缩和舒张,产生优于RVA-_VVI起搏的血液动力学效果。     

Comparison of non-invasive electrohysterographic recording techniques for monitoring uterine dynamics

Non-invasive recording of uterine myoelectric activity (electrohysterogram, EHG) could provide an alternative to monitoring uterine dynamics by systems based on tocodynamometers (TOCO). Laplacian recording of bioelectric signals has been shown to give better spatial resolution and less interference than mono- and bipolar surface recordings. The aim of this work was to study the signal quality obtained from monopolar, bipolar and Laplacian techniques in EHG recordings, as well as to assess their ability to detect uterine contractions. Twenty-two recording sessions were carried out on singleton pregnant women during the active phase of labour. In each session the following simultaneous recordings were obtained: internal uterine pressure (IUP), external tension of abdominal wall (TOCO) and EHG signals (5 monopolar and 4 bipolar recordings, 1 discrete approximation to the Laplacian of the potential and 2 estimates of the Laplacian from two active annular electrodes). The results obtained show that EHG is able to detect a higher number of uterine contractions than TOCO. Laplacian recordings give improved signal quality over monopolar and bipolar techniques, reduce maternal cardiac interference and improve the signal-to-noise ratio. The optimal position for recording EHG was found to be the uterine median axis and the lower centre-right umbilical zone.     

A wireless multi-channel neural amplifier for freely moving animals

Conventional neural recording systems restrict behavioral experiments to a flat indoor environment compatible with the cable that tethers the subject to recording instruments. To overcome these constraints, we developed a wireless multi-channel system for recording neural signals from rats. The device takes up to 64 voltage signals from implanted electrodes, samples each at 20 kHz, time-division multiplexes them into one signal and transmits that output by radio frequency to a receiver up to 60 m away. The system introduces <4 μV of electrode-referred noise, comparable to wired recording systems, and outperforms existing rodent telemetry systems in channel count, weight and transmission range. This allows effective recording of brain signals in freely behaving animals. We report measurements of neural population activity taken outdoors and in tunnels. Neural firing in the visual cortex was relatively sparse, correlated even across large distances and was strongly influenced by locomotor activity.     

Analysis and processing of laser Doppler perfusion monitoring signals recorded from the beating heart

Laser Doppler perfusion monitoring (LDPM) can be used for monitoring myocardial perfusion in the non-beating heart. However, the movement of the beating heart generates large artifacts. Therefore the aim of the study was to develop an LDPM system capable of correlating the laser Doppler signals to the cardiac cycle and to process the signals to reduce the movement artifacts. Measurements were performed on three calves, both on the normal beating heart and during occlusion of the left anterior descending coronary artery (LAD). The recorded LDPM signals were digitally processed and correlated to the sampled ECG. Large variations in the output (perfusion) and DC signals during the cardiac cycle were found, with average coefficients of variation of 0.36 and 0.14 (n-14), respectively. However, sections with a relatively low, stable output signal were found in late diastole, where the movement of the heart is at a minimum. Occlusion of the LAD showed the importance of recording the laser Doppler signals at an appropriate point in the cardiac cycle, in this case late systole, to minimise movement artifacts. It is possible to further reduce movement artifacts by increasing the lower cutoff frequency when calculating the output signal.     

Signal processing technique for non-invasive real-time estimation of cardiac output by inductance cardiography (thoracocardiography)

Inductance cardiography (thoracocardiography) non-invasively monitors changes in stroke volume by recording ventricular volume curves with an inductive plethysmographic transducer encircling the chest at the level of the heart. Clinical application of this method has been hampered, as data analysis has not been feasible in real time. Therefore a novel, real-time signal processing technique for inductance cardiography has been developed. Its essential concept consists in performance of multiple tasks by several, logically linked signal processing modules that have access to common databases. Based on these principles, a software application was designed that performs acquisition, display, filtering and ECG-triggered ensemble averaging of inductance signals and separates cardiogenic waveforms from noise related to respiration and other sources. The resulting ventricular volume curves are automatically analysed. Performance of the technique for monitoring cardiac output in real time was compared with thermodilution in four patients in an intensive care unit. The bias (mean difference) among 76 paired thoracocardiographic and thermodilution derived changes in cardiac output was 0%; limits of agreement (±2 SD of the bias) were ±25%. It is concluded that the proposed signal processing technique for inductance cardiography holds promise for non-invasive, real-time estimation of changes in cardiac output.     

成人心传导系统的增龄性超微结构

目的　观察成人心传导系统超微结构的增龄性变化。方法　采用纵切法分别对窦房结、房室结及房室束取材 ;以横切法取房室束 ,透射电镜观察。结果　 (1)从 2 8岁开始、随年龄增长窦房结和房室结的P细胞发生退行性变 ,表现为线粒体肿胀、空泡及髓鞘样变性、细胞体积变小 ,脂褐素大量增大 ,肌节紊乱、肌丝溶解 ,细胞出现脂肪变性、萎缩、凋亡等变化。T细胞见电子密度有明显区别呈明细胞和暗细胞两种 ,暗细胞线粒体大 ,嵴增多 ,显示功能活跃状态 ,明细胞反之 ;(2 )间质纤维、脂肪组织也伴随逐渐增多 ;(3)房室束的增龄性变化主要表现为束细胞线粒体萎缩及纤维组织逐渐增多 ,束带增宽。结论　采用电镜技术 ,发现心传导系统的细胞分子水平的增龄性变化比光镜下细胞水平提前约 10年。     

Two-Photon Excitation of di-4-ANEPPS for Optical Recording of Action Potentials in Rabbit Heart

Cardiac action potentials have been measured with single-photon excitation (SPE) of transmembrane voltage-sensitive fluorescent dye. Two-photon excitation (TPE) may have advantages for localization and depth of the tissue region from which the action potential is measured. However measurements of action potentials with SPE have not been demonstrated. We sought to develop a method for TPE of di-4-ANEPPS and test whether the method yields voltage-dependent fluorescence in cardiac tissue. We modified our SPE and ratiometric fluorescence recording system to use a femtosecond pulsed near-infrared laser. Modifications were made to enhance fluorescence collection efficiency and to block infrared laser light from entering the fluorescence collection system. Fluorescence was collected simultaneously in green (510–570nm) and red (590–700nm) wavelength bands. Action potentials were observed in the ratio of the green signal to the red signal, but were not observed above the noise level in either of the individual signals. Incorporation of a common-mode noise subtraction method revealed action potentials in green and red signals. We also found that the di-4-ANEPPS fluorescence emission spectrum for TPE at 930nm was similar to the emission spectrum for SPE at 488nm. The multiphoton method may be beneficial for highly localized cardiac optical measurements.