组织多普勒评估年龄及性别对左心室舒张功能及左心室充盈压的影响

目的 应用脉冲多普勒及组织多普勒成像评价年龄及性别对健康人左心室舒张功能及左心室充盈压的影响。方法 健康体检人员共213名,按年龄分为6组(20~29、30~39、40~49、50~59、60~69和70~87岁组),测量二尖瓣舒张早期血流峰值速度(E)、舒张晚期血流峰值速度(A)、二尖瓣环侧壁舒张早期运动速度(Em),计算E/A、E/Em。分析年龄、性别与以上各参数的相关性。结果 年龄与E、E/A呈负相关(r=－0.53、－0.70,P<0.01),与A呈正相关(r=0.58,P<0.01),与Em呈负相关(r=－0.75,P<0.01),与E/Em呈正相关(r=0.41,P<0.01)。随着年龄的增长,E、E/A逐渐降低,A逐渐升高,在50岁后出现E/A<1,Em逐渐降低,E/Em逐渐增高,70岁后E/Em明显增高。男性E/Em值(6.04±1.05)与女性E/Em值(6.57±1.87)比较差异有统计学意义(P<0.05),且70~87岁组女性E/Em高于男性(P<0.01)。结论 E、A、E/A、Em及E/Em与增龄关系密切,组织多普勒指标更敏感,E/Em值在70~87岁组中女性高于男性,70~87岁组女性较男性舒张功能指标减低更显著,应用二尖瓣血流频谱及组织多普勒评价左心室舒张功能及左心室充盈压时应充分考虑年龄及性别的影响,应根据不同年龄段及性别给出相应的参考数值。     

双多普勒同步成像技术评价高血压患者不同左心室构型的左心室舒张功能

目的 探讨双多普勒同步成像技术评价高血压患者不同左心室构型左心室舒张功能的价值。方法 将179例高血压患者(高血压组)根据左心室心肌质量指数(LVMI)和相对室壁厚度(RWT)分为4亚组,即正常构型、向心重构型、离心肥厚型及向心肥厚型亚组;选取62名健康志愿者为对照组。随机选取73例患者,分别采用传统非同步模式和双多普勒同步模式测量相同参数,采用Bland-Altman法和组内相关系数(ICC)对两种模式行可重复性检验。采用双多普勒同步技术计算同一心动周期的二尖瓣口舒张早期峰值流速(E)和组织多普勒(TDI)二尖瓣环侧壁(L)二尖瓣环舒张早期峰值速度(e'')的比值[E/e''(L)];同步计算二尖瓣口E峰和TDI二尖瓣环室间隔(S)舒张早期峰值速度(e'')的比值[E/e''(S)];同步计算二尖瓣口E峰和舒张期二尖瓣口血流传播速度(Vp)的比值(E/Vp)。结果 高血压各亚组E/e''(S)、E/e''(L)、E/Vp均高于对照组(P均<0.05),向心肥厚亚组E/e''(S)、E/e''(L)、E/Vp分别高于正常构型亚组和向心重构亚组,余各组间比较差异无统计学意义,但正常构型亚组、向心重构亚组、离心肥厚亚组及向心肥厚亚组E/e''(S)、E/e''(L)、E/Vp均呈依次增高的趋势。Bland-Altman法显示双多普勒模式较非同步模式测量的E/e''(L)、E/e''(S)、E/Vp的可重复性更好,ICC值更高。结论 双多普勒同步成像技术较非同步模式重复性更好,可有效地评价高血压患者不同左心室构型的舒张功能受损情况。     

双通道多普勒超声成像技术评价扩张型心肌病患者心功能的应用价值

选择临床确诊的DCM患者30例作为观察组,随机抽取40例健康人作为对照组进行研究,每位患者均行常规超声心动图检查,测量二尖瓣舒张早期峰值流速(E峰)和舒张晚期峰值流速(A峰),并采用双通道多普勒法(DPw)和传统方法分别获得左心室Tei指数和舒张早期二尖瓣血流峰值流速(E)与彩色M型舒张早期血流传播速度(Vp)比值(E/Vp),观察对比分析各组心脏结构及心功能参数的差异性。结果观察组两种方法测得Tei指数和E/Vp均高于对照组(P0.05);与传统方法相比,双通道多普勒超声成像技术测的Tei指数和E/Vp均增大(P0.05)。双通道多普勒超声成像技术测量Tei指数及E/Vp不受心律的影响,可作为准确敏感评估DCM患者左心室功能的指标。     

组织多普勒联合左心房容积指数评价食管癌患者放疗后早期心脏损伤

目的 探讨左心房容积指数(LAVI)联合组织多普勒评价食管癌患者放疗后左心功能早期损伤的价值。方法 对40例首次接受胸部放疗的食管癌患者,于放疗前、放疗后进行超声心动图检查,记录常规超声参数、组织多普勒参数及LAVI,并进行统计学分析,分析LAVI与舒张早期二尖瓣血流速度(E)/二尖瓣环舒张早期峰值速度(Em)的相关性。结果 与放疗前相比,常规超声指标放疗前后无明显变化(P均>0.05);放疗后二尖瓣环舒张期峰值速度(Sm)、Em、Em/二尖瓣环舒张晚期峰值速度(Am)降低,Am和E/Em升高,LAVI放疗后亦升高,且LAVI与E/Em呈正相关(r=0.87,P<0.001)。结论 食管癌患者接受放疗后,早期放射性心脏损伤主要表现为心脏舒张功能减退,组织多普勒、E/Em、LAVI可作为早期左心功能损伤的较好指标。     

彩色多普勒超声评价超重人群心脏结构、功能及颈动脉内-中膜厚度

目的 应用彩色多普勒超声检查观察超重对心脏结构、功能及颈动脉内-中膜厚度(IMT)的影响。方法 根据体质量指数(BMI)将100名体检者分为正常对照组(BMI<25 kg/m²,47名)和超重组(BMI≥25 kg/m²,53名)。对两组均行彩色多普勒超声心动图及颈动脉超声检查,分析超重对心脏结构、功能及颈动脉IMT的影响。结果 与正常对照组相比,超重组左心室舒张末期内径(LVDD)、左心室舒张末期室间隔厚度(IVST)、左心室后壁舒张末期厚度(LVPWT)、左心室质量(LVM)、左心室质量指数(LVMI)、二尖瓣舒张晚期峰值血流速度(A峰)、颈动脉IMT增高,二尖瓣舒张早期峰值血流速度(E峰)和E／A降低,差异均有统计学意义(P均<0.05)。BMI与LVDD、IVST、LVPWT、LVM、LVMI、A峰、颈动脉IMT均呈显著正相关(P均<0.05),与E/A、E峰均呈负相关(P均<0.01)。结论 超声检查发现无任何临床症状的超重人群可发生左心室增大、舒张功能减退以及颈动脉IMT。     

高血压患者冠状动脉血流储备下降对左心室舒张功能减退的影响

目的 探讨血压控制达标的高血压患者冠状动脉血流储备（CFR）对左心室舒张功能的影响。方法 对86例血压控制达标、且经CAG或冠状动脉CTA证实冠状动脉狭窄<50%的高血压患者行经胸多普勒超声心动图ATP负荷试验,检测冠状动脉左前降支的CFR;测定ATP负荷前后左心室舒张功能参数,包括舒张早期、舒张晚期二尖瓣血流速度（E、A）和左心室侧壁及间隔二尖瓣环舒张早期、舒张晚期运动速度（Em、Am）,分析CFR与左心室舒张功能参数的关系。结果 入组患者总体CFR为2.85±0.67,其中47例CFR<3（2.35±0.40）,39例CFR≥3（3.45±0.36）。CFR<3时,CFR与ATP负荷后侧壁Em呈正相关（r=0.42,P=0.003）,且为ATP负荷后侧壁Em的独立影响因素（P=0.015）。结论 血压控制达标且排除冠心病的高血压患者中,约50%存在冠状动脉微循环障碍;有微循环障碍的高血压患者CFR下降是左心室舒张功能减退的独立影响因素。     

高血压对非体外循环下冠状动脉搭桥术前后左心室舒张功能变化的影响

目的 探讨对伴有高血压的冠心病患者行非体外循环下冠状动脉搭桥术前后的左心室舒张功能变化特点。 方法 93例接受非体外循环下冠状动脉搭桥术的患者根据是否合并高血压病,分为高血压组(HP组,38例)和血压正常组(NBP组,55例),术前、术后分别采集过二尖瓣的舒张早期(E)和舒张晚期(A)峰速及二尖瓣侧壁瓣环的收缩期(Sm)、舒张早期(Em)和舒张晚期(Am)峰速。 结果 HP组术前室壁运动积分(WMI)及肺动脉收缩压低于NBP组(P＜0.05);NBP组患者的术前E/A和E/Em值显著高于HP组(P＜0.05),术后1个月E/Em值即可降至接近正常范围,而HP组患者的E/Em值术后3个月才接近正常;两组患者的左心室射血分数术前均降低,术后1个月恢复正常。HP组患者左心室舒张功能分级较集中于1级和2级,共33例(33/38,86.84%),而NBP组患者各级所占比重较分散,最多为3级,20例(20/55,36.36%),其次为2级,17例(17/55,30.91%)。 结论 NBP组患者的左心室舒张功能受损程度较HP组严重;合并高血压的患者左心室舒张功能恢复较慢,长期、稳定降压治疗是改善冠状动脉搭桥术预后的有效措施。     

二维斑点追踪显像评价阵发性房颤患者左心房功能

目的 应用二维斑点追踪显像(STI)技术评价阵发性房颤(PAF)患者左心房功能变化。 方法 分别对30例PAF患者(PAF组)和30名正常人(对照组)进行常规超声心动图检查,测定左心房内径(LAD)、舒张早期二尖瓣跨瓣血流速度(E)、舒张晚期二尖瓣跨瓣血流速度(A)、E/A、肺静脉收缩峰值流速(PVs)、肺静脉舒张峰值流速(PVd)、肺静脉收缩峰值流速/舒张峰值流速(S/D)、心房收缩期流入肺静脉血流流速(PVa),计算左心房最大容积(LAVmax)、左心房最小容积(LAVmin)、左心房收缩前容积(LAVp)、左心房被动射血分数(LAPEF)和左心房主动射血分数(LAAEF);应用STI技术获取左心房各壁各节段的应变率曲线,分别测量左心室收缩期左心房峰值应变率(SRs)、左心室舒张早期左心房峰值应变率(SRe)和左心室舒张晚期左心房峰值应变率(SRa),计算其平均值(mSRs、mSRe、mSRa)。 结果 与对照组比较,PAF组LAD、LAVmax、LAVp、LAVmin增大(P<0.05),LAAEF、LAPEF减低(P<0.05);E升高、A减低、E/A升高(P<0.05),PVs、PVd减低,S/D减低(P<0.05);PAF组左心房各壁各节段SRs、SRe和SRa降低,差异有统计学意义(P<0.05)。PAF组中,SRs与SRe及SRa之间无相关性(P>0.05),mSRa与LAAEF之间呈正相关(r=0.78,P<0.01);对照组中,SRs分别与SRe及SRa呈负相关(r分别为-0.347、-0.384,P<0.05)。 结论 PAF患者左心房各壁应变率峰值减低,左心房辅泵功能、管道功能和储蓄功能相互代偿作用减弱或消失。     

扩张型心肌病抗心力衰竭治疗早期疗效的超声心动图评估

目的 对比观察二维、彩色多普勒及脉冲组织多普勒超声心动图对扩张型心肌病(DCM)抗心力衰竭治疗后早期疗效的评估.方法 正常对照组和DCM 患者治疗前及治疗后2 周,超声测量左心室射血分数(LVEF)、二尖瓣口血流多普勒E、A 峰及组织多普勒-二尖瓣环收缩期和舒张早、晚期运动速度峰值Sm、Em、Am,并计算E/A、Em/Am.结果 DCM 患者抗心力衰竭治疗2 周后,临床疗效达显效或有效者,LVEF、E/A 较治疗前无显著提高,脉冲多普勒组织成像(PW-TDI)指标Sm亦无改善;而Em、Em/Am 虽仍低于对照组,但较治疗前显著升高.结论 DCM 抗心力衰竭治疗后早期疗效主要得益于左心室舒张功能的改善;二尖瓣环PW-TDI 反映左心室舒张功能改善是较血流多普勒更敏感的指标.     

年龄对心血管僵硬度的影响

目的 分析年龄因素对心血管僵硬度的影响。 方法 将447名接受体检者分成6个年龄组,分别行超声心动图检查,测量舒张末期室间隔厚度(IVSd)和左心室后壁厚度(LVPWd),左心室舒张期内经(LVIDd)和收缩期内径(LVIDs);测量、计算心功能参数:Tei指数,二尖瓣口舒张早、晚期血流速度峰值比(E/A),二尖瓣环舒张早、晚期速度峰值比(e/a),二尖瓣舒张早期血流及瓣环速度峰值比(E/e),射血分数(EF);检测动脉僵硬度参数:心踝血管指数(CAVI)和颈-股脉搏波速度(CFPWV)。对各年龄组进行组间比较和相关分析。 结果 IVSd及LVPWd随年龄增加而增厚,差异有统计学意义(P均<0.001);Tei指数、E/A、e/a、E/e随年龄增加而变化,差异有统计学意义(P均<0.05);动脉僵硬参数CAVI和CFPWV随年龄增加而增大(P均<0.001)。动脉僵硬参数CAVI和CFPWV与心脏Tei指数、E/A、e/a、E/e显著相关(P均<0.05);控制年龄偏相关分析显示CAVI与Tei指数、CFPWV与E/A显著相关(P<0.001)。 结论 年龄是动脉、心脏僵硬度增加的重要影响因素,心脏与血管僵硬度相互影响。     

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.     

Clinical Pharmacokinetics of Morphine

Morphine, the most widely used mu-opioid analgesic for acute and chronic pain, is the standard against which new analgesics are measured. A thorough understanding of the pharmacokinetics of morphine is required in order to safely and effectively use this analgesic in a wide variety of patients with different levels of organ function. A MEDLINE search was conducted to identify literature published between 1966 and January 2002 relevant to the pharmacokinetics of morphine. These publications were reviewed and the literature summarized regarding unique and clinically important elements of morphine disposition relative to its parenteral administration (including intravenous, intramuscular, subcutaneous, epidural and intrathecal administration), absorption profile (immediate release, controlled release, and sublingual/buccal, and rectal administration), distribution, and its metabolism/ excretion. Special populations, including infants, elderly, and those with renal/liver failure, have a unique morphine pharmacokinetic profile that must be taken into account in order to maximize analgesic efficacy and reduce the risk of adverse events.