不同心脏起搏方式对左室收缩功能的影响

目的应用超声心动图方法探讨不同心脏起搏方式对左室收缩功能的影响，选择30例置入DDD起搏器的病窦综合征患者。将起搏方式由DDD随机程控为VVI，AAI模式，观察左室收缩功能指标；每次测量间隔5min以上。结果VVI起搏时左室收缩功能最差，与AAI和DDD起搏相比，VVI起搏时收缩功能标：SV，CO，EF均明显降低，而ESV明显增大。与DDD起搏相比，AAI起搏时SV，CO，LVEF均明显增大。结论房室同步和心室同步对左室收缩功能均有重要影响；病窦综合征患者，加强心室起搏管理，在提供双腔支持的安全前提下，以AAI（R）模式作为基本治疗模式，减少右心室起搏，对改善患者的左室功能有重要意义。     

医学名词介绍(7) 心血管病学(上)

汉文名英文名心房同步心室起搏　atrialsynchronousventricularpacing ,VAT心房非同步起搏atrialasynchronouspacing,AOO心室非同步起搏ventricularasynchronouspacing,VOO非同步型房室顺序起搏asynchronousatrioventricularsequentialpacing ,DOO触发型起搏triggeredpacing心房触发型起搏atrialtriggeredpacing,AAT心室触发型起搏ventriculartriggeredpacing ,VVT抑制型起搏inhibitedpacing心房抑制型起搏atrialinhibitedpacing ,AAI心室抑制型起搏ventricularinhibitedpacing,VVI心房同步心室抑制型起搏atrialsynchronousventri…     

不同起搏方式对血流动力学的急性影响

目的：探讨不同起搏方式对病窦综合征患者血流动力学的急性影响。方法：Swan-Ganz漂浮导管测量14例病窦综合征患者起搏前及VVI、AAI、DDD起搏时血流动力学参数；并根据VVI起搏时室房传导的情况分组对比。结果：起搏前及起搏时，平均动脉压(MAP)无明显差异。AAI、DDD起搏时，右房压(RAP)、平均肺动脉压(PAP)、肺毛细血管楔嵌压(PCWP)与起搏前对比无明显改变，但较VVI起搏明显下降(P＜0．01)；心输出量(CO)较起搏前及VVI起搏时显著增加(P＜0．01)。AAI、DDD起搏间对比无显著性差异。VVI起搏时，RAP、PAP、PCWP较起搏前显著增加，室房传导组更为明显；无室房传导组较起搏前CO略有增加(P＜0．05)，而室房传导组CO改变不明显；室房传导组较无室房传导组RAP、PCWP显著增加(P＜0．05)。结论：AAI、DDD起搏可以显著增加CO，对血流动力学影响较小；VVI起搏特别存有室房传导时，可导致血流动力学明显异常；AAI、DDD起搏明显优于VVI起搏。     

心房按需起搏术中配合及术后护理体会

心房按需起搏(AAI)适用于房室传导功能正常的病态窦房结综合征,是一种合理、安全、简单、经济且效果好的生理性起搏方式。与常用的心室起搏(VVI)相比,AAI起搏具有以下优点:①保持了正常的房室收缩顺序,不降低心输出量;②可避免VVI起搏时因室—     

超声斑点跟踪显像评价房室顺序起搏患者左心室收缩功能

目的探讨超声斑点跟踪显像技术评价房室顺序起搏患者左心室收缩功能的价值。方法用超声斑点跟踪显像技术分别检测房室顺序起搏心房起搏心房感知抑制型(AAI)模式患者10例(A组)、房室顺序起搏双心腔起搏双心腔感知触发和抑制型(DDD)模式患者10例(B组)及正常对照10例(C组)的左心室16个节段的径向位移、速度及应变指标,并与常规超声心动图测量所得左心室射血分数(EF值)进行相关分析和比较。结果三组间左心室EF值、收缩期16节段径向位移峰值均数、径向速度峰值均数与径向应变峰值均数差异均无统计学意义(P>0.05)。B组与C组相比,径向位移峰值在左心室下壁基底段、间隔基底段及心尖段降低,径向应变峰值在下壁及间隔心尖段降低,差异有统计学意义(P<0.05)。A组与C组相比,左心室各个节段的径向位移、径向速度与径向应变峰值差异均无统计学意义(P>0.05)。结论房室顺序起搏DDD模式时,左心室下壁及间隔的基底段和心尖段收缩功能降低,AAI模式时左心室节段性收缩功能无明显改变。     

病态窦房结综合征伴房室传导延迟患者心房按需起搏与房室同步起搏模式左心功能的超声评价

目的 运用多普勒超声心动图及组织多普勒(TDI)技术评价病态窦房结综合征(SSS)伴房室传导延迟患者分别在心房按需起搏(AAI)与房室同步起搏(DDD)模式下的心脏功能,并探讨其起搏模式的选择.方法 选择植入DDD起搏器的SSS伴Ⅰ度房室传导阻滞的患者24例,分别置于AAI模式和房室间期优化的DDD模式,应用多普勒超声心动图和TDI技术评价这两种起搏模式下心脏的收缩和舒张功能.结果 多普勒超声心动图评价心脏收缩功能(EF,主动脉VTI)和舒张功能(E/A)参数在AAI组和DDD组之间差异无统计学意义.TDI显示收缩峰值速度(Sm)在AAI组为(10.88±2.92)cm/s,DDD组为(9.06±2.49)cm/s;舒张早期峰值速度(Em)、舒张早期峰值速度/舒张晚期峰值速度(Em/Am)在AAI组和DDD组分别为[(9.25±2.89)cm/s 对 (8.37±2.31)cm/s、0.96±0.35 对 0.80±0.25];Tei指数在AAI组为 0.56±0.12,DDD组为 0.80±0.40.这些参数在两组间差异有统计学意义(P《0.05).结论 ①SSS伴房室传导延迟(PR》200 ms且《260 ms)患者采用AAI起搏模式心脏收缩和舒张功能的改善优于DDD起搏模式;②TDI技术较多普勒超声心动图能更敏感地反映心脏收缩和舒张功能的变化.     

彩超对人工心脏起搏的血液动力学研究

目的　本文采用彩色多普勒超声心动图研究了心脏起搏前、后的血液动力学变化 ,以评价不同起搏模式血液动力学效应。方法　对 32例植入人工心脏起搏器的患者 ,采用 M型、二维及多普勒超声心动图检测了心室按需起搏 (VVI)不伴室房逆传 (A组 )和伴室房逆传 (B组 )及房室顺序起搏 (AVP) (C组 )的左心结构、左室的泵血功能、左室收缩及舒张功能指标。结果　 1 .心室起搏 (VP)不伴室房逆传和房室顺序起搏(AVP)组起搏后的心输出量 (CO)明显增加 (P<0 .0 5〉,而 VP伴室房逆传组则 CO增加不明显 (P>0 .0 5 )。心搏量 (SV)各组均呈下降趋势 ,VP伴室房逆传者下降更明显。但起搏后三组间比较无显著差异 (P>0 .0 5 ) ;2 .VP后左室的收缩及舒张功能均有受损 ,而 AVP后主要损害左室的舒张功能 ,对左室收缩功能影响不明显 ;3.VP伴室房逆传者 ,起搏后血液动力学效应在三组间最差。结论　无论 VP还是 AVP起搏后由于心率的增加均可使CO增加 ,但对左室的功能均有不同程度的损害 ,VP伴室房逆传者最为明显 ,AVP损害程度三组间最轻。因此 ,AVP也并非真正的生理起搏器。临床上提倡埋植更接进生理状态的起搏器 (多部位心脏起搏 ) ,以保持良好的心功能状态     

超声心动图在心脏再同步化治疗室间间期优化中的应用

目的 探讨超声心动图在心脏再同步化治疗(CRT)室间间期(VVD)优化中的价值.方法 7例CRT患者行VVD优化,比较不同VVD的超声心动图指标的即刻差异.结果 7例中左心室优先优于右心室优先和双室同步起搏:左心室优先时超声心动图测量的心功能指数(Tei指数)、左右心室射血前期延迟(PETd)、左心室壁12节段收缩达峰速时间标准差(TS-12-SD)、左心室收缩后收缩(PSS)减小,左心室收缩期压力上升速率(dp/dt)、主动脉流速时间积分(VTIAV)增大(P均＜0.05);左心室射血分数(EF)增高,但差异无统计学意义;双室同步起搏与右心室起搏的超声心动图各项指标均差异无统计学意义(P均＞0.05).最优VVD分布在10～30 ms,但个体差异明显.结论 超声心动图指导下CRT患者VV间期优化可使CRT患者获得即刻血流动力学指标改善.     

实时三维超声心动图评价DDD模式起搏器植入患者左室心肌收缩同步性

目的 探讨实时三维超声心动图评价房室顺序双心腔起搏双心腔感知触发和抑制型(DDD)模式起搏器植入患者左室心肌收缩同步性的价值及其临床意义.方法 应用实时三维超声心动图对20例DDD模式起搏器植入患者和20例正常人行左室心肌同步性检测.经QLab软件分析,得到左心室舒张末期容积(LEDV)、收缩末期容积(LESV)、每搏量(SV)、射血分数(LVEF)、17节段心电图QRS波起始点至左心室最小容积点时间的平均值(Tmean)及其标准差(T～SD)、17节段心电图QRS波起始点至左心室最小容积点时问的最大差值(Tmax)、17节段时间容积曲线.结果 与对照组相比,病例组LESV增大(P＜0.01),LVEF、SV减小(P＜0.01),T-SD、Tmax延长(P＜0.01);两组年龄、心率、LEDV、Tmean差异均无显著性意义(P＞0.05).结论 DDD模式起搏器植入患者左室心肌收缩同步性存在一定程度异常,应用实时三维超声心动图可对其进行定量评价.     

速度矢量成像技术对急性期川崎病患儿左心收缩功能的评价

【目的】使用速度矢量成像（VVI）技术评价急性期川崎病（KD）患儿的左心室纵向收缩功能,探讨VVI对于急性期KD患儿左心收缩功能的诊断价值。【方法】对32例临床确诊KD急性期患儿,根据有无冠状动脉扩张,将其分为冠脉扩张组、无冠脉扩张组两组,并与30例正常儿童左心室收缩功能数据对照,常规测量左心室射血分数（EF）,左室缩短率（FS）,每搏量（SV）,使用VVI技术测量左心室各节段最大纵向运动速度（Vp）,应变（s）,应变率（SR）。【结果】所有研究对象EF、FS、SV测值无统计学意义（P〉0．05）;冠脉扩张组、无冠状动脉扩张组Vp,S,SR均较正常对照组降低（P〈0．05）;冠状动脉扩张组较无冠状动脉扩张组的Vp,S,SR测值在基底段、中间段下降（P〈0．05）。【结论】常规超声心动图检测急性KD患儿左心整体功能正常时,VVI技术显示左心室收缩功能出现减退,提示VVI技术可以定量评估早期左心室收缩功能。     

Determination of creatine kinase isoenzyme MB activity in serum using immunological inhibition of creatine kinase M subunit activity. Activity kinetics and diagnostic significance in myocardial infarction.

This is a new method for the determination of creatine kinase isoenzyme MB activity in serum. The method uses direct activity measurement of creatine kinase B subunit activity after blocking of CK-M subunit activity by inhibiting antibodies. The test takes no longer than 15 min. The method yields an intra-serial C.V. of 2.0-12.9%, and a C.V. from day to day of 5.5%. The detection limit is 3.4 U/l creatine kinase MB. In the 95 cases with proven myocardial infarction several types of creatine kinase MB activity kinetics could be determined. The percentage of creatine kinase MB of peak CK-total is 6-25%, with a mean of 11.1%. The amount of creatine kinase MB with respect to total CK activity after reinfarction is higher than the amount after initial infarction.     

Dissociable correlates of two classes of retrieval processing in prefrontal cortex

Although substantial evidence suggests that the prefrontal cortex (PFC) implements processes that are critical for accurate episodic memory judgments, the specific roles of different PFC subregions remain unclear. Here, we used event-related functional magnetic resonance imaging to distinguish between prefrontal activity related to operations that (1) influence processing of retrieval cues based on current task demands, or (2) are involved in monitoring the outputs of retrieval. Fourteen participants studied auditory words spoken by a male or female speaker and completed memory tests in which the stimuli were unstudied foil words and studied words spoken by either the same speaker at study, or the alternate speaker. On "general" test trials, participants were to determine whether each word was studied, regardless of the voice of the speaker, whereas on "specific" test trials, participants were to additionally distinguish between studied words that were spoken in the same voice or a different voice at study. Thus, on specific test trials, participants were explicitly required to attend to voice information in order to evaluate each test item. Anterior (right BA 10), dorsolateral prefrontal (right BA 46), and inferior frontal (bilateral BA 47/12) regions were more active during specific than during general trials. Activation in anterior and dorsolateral PFC was enhanced during specific test trials even in response to unstudied items, suggesting that activation in these regions was related to the differential processing of retrieval cues in the two tasks. In contrast, differences between specific and general test trials in inferior frontal regions (bilateral BA 47/12) were seen only for studied items, suggesting a role for these regions in post-retrieval monitoring processes. Results from this study are consistent with the idea that different PFC subregions implement distinct, but complementary processes that collectively support accurate episodic memory judgments.     

俯卧位通气对高海拔地区肺复张治疗无效急性呼吸窘迫综合征患者氧合的影响

目的 探讨俯卧位通气对高海拔地区肺复张术(RM)治疗无效急性呼吸窘迫综合征(ARDS)患者的治疗作用.方法 从海拔2260m的地区医院筛选RM治疗无效的41例ARDS患者[平均氧合指数( PaO2/FiO2)较RM前升高＜20％视为RM无效],依不同病因分为肺内源性ARDS组(ARDSp组)和肺外源性ARDS组(ARDSexp组),每组再按信封法随机分为俯卧位组和仰卧位组,即ARDSp俯卧位组(11例)、ARDSp仰卧位组(9例)、ARDSexp俯卧位组(10例)、ARDSexp仰卧位组(11例).在通气前及通气1、2、3、4h监测动脉血氧分压( PaO2)、PaO2/FiO2、静态顺应性(Cst)、气道阻力(Raw)的变化.结果 通气lh时,ARDSexp俯卧位组PaO2/FiO2( mm Hg,l mm Hg=0.133 kPa)即较通气前显著升高(157.4±40.6比129.3±48.7,P＜0.05),并随通气时间延长呈持续增高趋势,4h达峰值(219.1 ±41.1);且ARDSexp俯卧位组通气3h内PaO2/FiO2较其他3组显著增高,另3组间则差异无统计学意义.ARDSp俯卧位组、ARDSexp俯卧位组通气4h时PaO2/FiO2均较相应仰卧位组显著增高(208.8±39.7比127.4±47.1,219.1±41.1比124.9±50.8,均P＜0.05).4组通气前后Cst无显著改变,各组间差异也无统计学意义.ARDSp俯卧位组通气4h时Raw(cmH2O·L-1·s-1)较通气前显著降低(6.8±1.7比10.7±1.8,P＜0.05),且明显低于其他3组;其他3组各时间点Raw组内及组间比较差异均无统计学意义.结论 俯卧位通气作为ARDS机械通气重要策略之一,可以改善RM无效高原ARDS患者的氧合,为抢救患者赢得宝贵的时间.     

Digital imaging among medical facilities

The Department of Veterans Affairs (VA) in the USA operates a network of 172 medical centres which all utilize a hospital information system (HIS) which has been developed and is currently maintained by the VA. During the past several years, an image management and communication module has been developed, installed and clinically utilized at the Washington DC and Maryland VA Medical Centres. This image management and communication system, referred to as the decentralized hospital computer program (DHCP) imaging system, is fully integrated with a commercial picture archiving and communication system (PACS). The system is utilized to capture, archive, and display all images generated within the hospital including radiology, nuclear medicine, pathology, endoscopy, bronchoscopy, and dermatology, intraoperative photographs, ECG data, and a limited number of paper documents. The ultimate goal of the project is to have all patient text and image data available at any clinical workstation to any authorized user anywhere within the network of medical centres. Clinical requirements for an imaging workstation include ease of use, rapid and reliable access to the complete set of patient information, and images which are of acceptable quality to meet the requirements of the user and the subspecialty. Patient confidentiality and data security must be safeguarded at all times. Integration of the images with the remainder of the patient's database was found to be critical to the success of the project. The experience at the Washington and Maryland facilities suggests that an imaging system that is successfully integrated with a hospital information system can provide substantial clinical and economic benefits both within and among medical centres. Clinical acceptance and utilization of the system has been excellent, particularly in diagnostic radiology where DHCP Imaging has been interfaced to a commercial PAC system. Based upon this initial experience, the VA has begun to deploy the system throughout its large network of medical centres.     

Myocardial elastography at both high temporal and spatial resolution for the detection of infarcts

Myocardial elastography is a novel method for noninvasively assessing regional myocardial function, with the advantages of high spatial and temporal resolution and high signal-to-noise ratio (SNR). In this paper, in-vivo experiments were performed in anesthetized normal and infarcted mice (one day after left anterior descending coronary artery [LAD] ligation) using a high-resolution (30 MHz) ultrasound system (Vevo 770, VisualSonics Inc., Toronto, ON, Canada). Radiofrequency (RF) signals of the left ventricle (LV) in longitudinal (long-axis) view and the associated electrocardiogram (ECG) were simultaneously acquired. Using a retrospective ECG gating technique, 2-D full field-of-view RF frames were acquired at an extremely high frame rate (8 kHz) that resulted in high-quality incremental displacement and strain estimation of the myocardium. The incremental results were further accumulated to obtain the cumulative displacements and strains. Two-dimensional and M-mode displacement images and strain images (elastograms), as well as displacement and strain profiles as a function of time, were compared between normal and infarcted mice. Incremental results clearly depicted cardiac events including LV contraction, LV relaxation and isovolumetric phases in both normal and infarcted mice, and also evidently indicated reduced motion and deformation in the infarcted myocardium. The elastograms indicated that the infarcted regions underwent thinning during systole rather than thickening, as in the normal case. The cumulative elastograms were found to have higher elastographic SNR (SNR(e)) than the incremental elastograms (e.g., 10.6 vs. 4.7 in a normal myocardium, and 6.0 vs. 2.4 in an infarcted myocardium). Finally, preliminary statistical results from nine normal (m = 9) and seven infarcted (n = 7) mice indicated the capability of the cumulative strain in differentiating infracted from normal myocardia. In conclusion, myocardial elastography could provide regional strain information at simultaneously high temporal (>/=0.125 ms) and spatial ( approximately 55 microm) resolution as well as high precision ( approximately 0.05 microm displacement). This technique was thus capable of accurately characterizing normal myocardial function throughout an entire cardiac cycle, at the same high resolution, and detecting and localizing myocardial infarction in vivo.     

手转胎头术失败的原因与分娩结局临床分析

目的 探讨手转胎头术失败的原因与分娩结局.方法 选择2008年1月至2010年12月于我院住院分娩的持续性枕横位、枕后位产妇198例,根据行手转胎头术后结果分为成功组126例、失败组72例.比较两组分娩结局,对比分析失败原因.结果 失败组胎儿体质量≥3500 g的发生率[76.4％(55/72)]明显高于成功组[31.7％(40/126)],差异有统计学意义(x2=30.177,P=0.001)、失败组宫缩乏力发生率[58.3％(42/72)]高于成功组[38.1％ (48/126)],差异有统计学意义(x2=7.569,P=0.006)、失败组骨盆临界或轻度狭窄发生率[38.9％ (28/72)]高于成功组[23.8％(30/126)],差异有统计学意义(x2 =5.030,P=0.002)、失败组手转胎头时机不当(宫口开大＜6 cm、胎头位于坐骨棘上及宫口开大8～10 cm、胎头位于坐骨棘下≥2 cm)发生率[61.1％(44/72)]高于成功组[38.9％(49/126)],差异有统计学意义(x2=9.084,P=0.003).失败组母儿并发症(产后出血、产褥病率、胎儿窘迫、新生儿窒息)发生率高于成功组(x2 =9.586,P=0.002、x2=9.334,P=0.002、x2=5.910,P=0.015、x2=5.240,P=0.022)、失败组剖宫产发生率[72.2％(52/72)]明显高于成功组[34.1 ％(43/126),x2=26.641,P=0.001)].结论 手转胎头术能使难产变顺产,降低剖宫产率,减少母儿并发症,但须积极预防、处理导致手转胎头术失败的原因,对矫正失败后继续矫正及试产应慎重.