心肌缺血心电图QRS波群特征与ST段偏移量关联性分析

目的 分析心肌缺血心电图QRS波群特征与ST段偏移量的关联性.方法 提取心电信号的心拍模板,筛选各个心电心拍,计算QRS波群特征(QRS上升斜率、QRS下降斜率、角R、角Q)和ST段偏移量,最后分析各QRS波群特征随ST段偏移量的拟合趋势以及对应关系.结果 经公共数据库Long Term STdatabase(LTST...     

基于能量变换与小波分解的QRS波群检测算法

目的 使用能量变换与小波分解的联合算法检测心电信号QRS波群的特征点,为心电信号的自动分析提供新的手段.方法 能量变换是基于信号的局部特征的,可以有效地突出信号的峰点或谷点;小波分解对信号做多分辨率分解,可以突出信号的特征信息;两种方法的结合更利于QRS波群的检测.结果 使用30例样本检测算法性能,证明联合算法能够提高信噪比,对特征点的定位准确可靠.经MIT/BIH心电数据库的检测验证,其R波定位的正确率高达99.79%.使用心率趋势图分析计算结果,不仅可以完全纠正误检和漏检,而且能够定位异常的心搏.结论 本算法能够准确、实时地识别被噪声严重干扰的心电信号的QRS波群,因而在心电信号的自动分析中有很好的应用前景.     

高原地区藏汉健康青年QRS波振幅变化的研究

心电图（ECG）中的QRS波群代表左、右心室肌除极的电位变化,在人的成长过程中可因生理因素和病理因素发生振幅和时限的改变,QRS波振幅和时限异常是临床上诊断心脏疾病的常用指标。准确分析QRS波群所包含的信息和掌握其规律,在医学诊断中具有重要价值。因此,不同地域、民族及性别的健康人群ECG中QRS波振幅变化的研究就显得非常必要。以往关于QRS波的研究较多,但以藏区较高地区人群为研究对象尚少见报道。本文采集的几组心电图QRS波振幅资料,     

一例罕见的Mahaim氏型预激症侯群合并2:1房室传导阻滞心电图分析

患者,女性,31岁,近两星期来因感心慌,胸闷,心率时快时慢于2001年4月19日来我院就诊.自述以往身体健康,从未做过心电图,无心脏病史及家庭史.     

剪切波弹性成像:一种检测肝硬化病人肝静脉压力梯度变化的无创方法

目的研究剪切波弹性成像(SWE)肝脏硬度(LS)和肝脏硬度测量的变化(ΔLS)是否与肝静脉压力梯度(HVPG)相关,并且评估SWE估算门静脉高压病人肝静脉压     

基于嵌入式微机的便携心电监护仪设计

目的 研制一种实用的低功耗嵌入式便携心电监护仪。方法 以嵌入式微处理器RCA-CDP1802为核心。设计了硬件系统和控制软件,并嵌入了心电波形特征提取算法、心电数据压缩算法、心律失常分析算法,在硬件和软件设计时均考虑了降低功耗。结果 该仪器功耗低,体积小,重量轻,智能化程度高。它能连续48h实时监护患者的心电信号,实时分析10余种心律失常并存贮心律失常时的压缩心电数据。在需要时可将存贮的心电数据于串行接口输出供医生回顾分析。结论 该监护仪达到设计要求,实用性高。     

运动心电图检测系统中数据采集卡的研制

目的：研制一种能够高精度同步采集多路运动心电信号的专用数据采集卡。方法：1）硬件上，以196KC单片机为核心构成数据采集系统，设计可以完成数据采集、基本数据预处理及相关控制的数据采集卡；2）软件上，单片机完成A/D转换、信号的实时预处理以及与主机通信3大任务，主机则接收数据并且实时处理数据。结果：在运动心电图的检测系统中所设计的数据采集卡配合主机CPU实现了双处理器工作，同时为了减轻主机负担，由数据采集卡完成数据预处理功能，合理利用了硬件资源。结论：该数据采集卡能够满足运动心电图临床检测的要求。     

Fragmented QRS complexes not typical of a bundle branch block: A marker of greater myocardial perfusion tomography abnormalities in coronary artery disease

Background  Fragmented QRS (FQRS) complexes, not typical of a bundle branch block, are a marker of regional myocardial injury. The extent of stress myocardial perfusion imaging (MPI) abnormalities with FQRS patterns is not known. Methods and Results  Twelve-lead electrocardiograms (ECGs) in 501 patients undergoing stress MPI were studied. FQRS was defined as a QRS duration of 120 milliseconds or less, with notches or slurs of QRS complexes, on 2 contiguous leads of a coronary artery territory. Abnormal MPI was defined as a regional summed stress score (SSS) and summed rest score (SRS) of 3 or greater based on a 17-segment model. Patients with a typical bundle (n=26), paced rhythm (n=2), and Q waves (n=64) were excluded. Of the remaining 409 patients (mean age, 58±13 years; 52% male), 155 (38%) had FQRS on the ECG. FQRS patients had a higher mean SSS, SRS, and global summed difference score and a lower left ventricular ejection fraction (all P<.001), as well as greater regional stress MPI scar (69% vs 11%, P<.001), FQRS pattern sensitivity was 75% and specificity was 94% for a corresponding regional MPI scar. On logistic regression, SSS, SRS, summed difference score, left ventricular ejection fraction, and regional scar were univariate predictors of the FQRS pattern on the ECG (all P<.01), and any regional scar (odds ratio, 32; P<.001) was a multivariate predictor. Conclusions  FQRS complexes on an ECG are a marker of higher stress MPI perfusion and functional abnormalities. Regional FQRS patterns denote the presence of a greater corresponding focal regional myocardial scar on stress MPI     

Flow Velocities After Carotid Artery Stenting: Impact of Stent Design. A Fluid Dynamics Study in a Carotid Artery Model with Laser Doppler Anemometry

Purpose To study the influence of a newly developed membrane stent design on flow patterns in a physiologic carotid artery model.Methods Three different stents were positioned in silicone models of the carotid artery: a stainless steel stent (Wall-stent), a nitinol stent (SelfX), and a nitinol stent with a semipermeable membrane (MembraX). To increase the contact area of the membrane with the vessel wall, another MembranX model was modified at the outflow tract. The membrane consists of a biocompatible silicone-polyurethane copolymer (Elast-Eon) with a pore size of 100 m. All stents were deployed across the bifurcation and the external carotid artery origin. Flow velocity measurements were performed with laser Doppler anemometry (LDA), using pulsatile flow conditions (Re = 220; flow 0.39 l/min; flow rate ratio ICA:ECA = 70:30) in hemodynamically relevant cross-sections. The hemodynamic changes were analyzed by comparing velocity fluctuations of corresponding flow profiles.Results The flow rate ratio ICA:ECA shifted significantly from 70/30 to 73.9/26.1 in the MembraX and remained nearly unchanged in the SelfX and Wallstent. There were no changes in the flow patterns at the inflow proximal to the stents. In the stent no relevant changes were found in the SelfX. In the Wallstent the separation zone shifted from the orifice of the ICA to the distal end of the stent. Four millimeters distal to the SelfX and the Wallstent the flow profile returned to normal. In the MembraX an increase in the central slipstreams was found with creation of a flow separation distal to the stent. With a modification of the membrane this flow separation vanished. In the ECA flow disturbances were seen at the inner wall distal to the stent struts in the SelfX and the Wallstent. With the MembraX a calming of flow could be observed in the ECA with a slight loss of flow volume.Conclusions Stent placement across the carotid artery bifurcation induces alterations of the physiologic flow behavior. Depending on the stent design the flow alterations are located in different regions. All the stents tested were suitable for the carotid bifurcation. The MembraX prototype has shown promising hemodynamic properties ex vivo.