老年原发性高血压患者晨峰现象与心血管事件

目的探讨老年原发性高血压患者血压晨峰（MBPS）对心率变异性（HRV）及心脏结构和功能损害的影响。方法老年原发性高血压患者164例,根据24小时动态血压监测（24ABPM）分为MBPS组（90例）和非MBPS组（74例）,常规检查动态心电图、心电图、超声心动图。分析HRV时域参数大小,测量计算QT间期、校正的QT间期（QTc）、QT离散度（QTd）和校正的QT离散度（QTcd）,测定左心室舒张末期内径（LVEDd）、舒张末期室间隔厚度（ZVST）、舒张末期左心室后壁厚度（LVPWT）及左心室质量指数（LVMI）。结果MBPS组的HRV时域指标均显著低于非MBPS组,包括项目24小时全程全部窦性R—R间期平均值的标准差（SDNN）（76．1±16．9）msvs（106．1±25．6）ms;24小时内每5分钟时段窦性R—R间期平均值的标准差（SDANN）（64．6±22．3）msvs（94．7±27．0）ms;全程全部窦性R—R同期的平方根（RMSSD）（23．2±13．2）mSVS（33．8±19．5）ms;两个相邻R—R间期互差〉50ms的心跳数所占分析信息间的期内心搏数的百分比（PNN50）（3．0±2．5）％vs（7．2±6．9）％（均P〈0．01）。MBPS组的QT间期、QTc、QTd、QTcd指标高于非MBPS组,QT（381．0±28．5）ms vs（360．0±25．9）ms;QTc（413．0±31．9）ms vs（403．0±29．0）ms;QTd（35．5±12．1）ms vs（32．2±10．2）ms;QTcd（40．2±5．9）ms vs（38．4±4．1）ms（均P〈0．05）．MBPS组LVMI、LVEDd、LVST及LVPWT均高于非MPBS组（均P〈0．01）。结论老年原发性高血压患者晨峰使心血管事件的风险增加。     

QT间期离散度及P波离散度与小儿扩张型心肌病预后的关系

目的　探讨QT间期离散度 (QTd)及P波离散度 (Pd)与小儿扩张型心肌病 (DCM)预后关系。方法　 5 2例DCM患儿 (研究组 ) ,男 31例 ,女 2 1例 ,年龄 3个月～ 18岁 ,平均 (5 79± 5 17)岁 ,死亡 5例。随机匹配健康儿童 5 2例为对照 (对照组 )。受检对象描记 12导联同步体表心电图 ,选择波形清晰的 3个心动周期自动分析合并人工干预测量心率 (HR)、QTd与Pd。结果　研究组较对照组心率增快 (P <0 0 5 ) ,P -R间期 (P <0 0 5 )、QRS间期 (P <0 0 1)及QTc间期 (P <0 0 1)延长 ;QT max增加 (P >0 0 5 ) ,QTd、Pmax、Pmin及Pd延长 (P <0 0 1)。死亡组与存活组比较QTd与Pd无差异 (P >0 0 5 )。结论　QTd和Pd在DCM患儿明显增大 ,但其对估测DCM预后价值有限。     

早期康复治疗对无合并症急性心肌梗死患者QT间期离散度的影响

目的 :探讨早期康复治疗对无合并症急性心肌梗死 (AMI )患者QT间期离散度 (QTd)的影响。方法 :113例研究对象前瞻性随机分为早期康复治疗组 (5 4例 )及对照组 (5 9例 )。两组主要基线资料具可比性。早期康复组采用期康复治疗方案 ,对照组采用传统方案。所有研究对象分别在入院当时 (平均 9.3h± 1.9h)、第 1周末、第 2周末、第 3周末记录标准 12导联心电图。QT间期的测量从QRS波起点至T波终点 ,同一导联测量 3个心动周期 ,取其平均值。不同导联最大QT值减去最小为QTd值。结果 :早期康复组入院当时、第 1周末、第 2周末、第 3周末QTd(分别为 6 4± 14ms,4 6± 15ms ,4 3± 12ms,39± 13ms )与对照组 (分别为 6 7± 12ms,4 8± 16ms ,4 1± 13ms,4 0± 15ms)比较统计学上无显著性差异 (P >0 .0 5 )。结论 :无合并症AMI患者实行早期康复治疗不影响QTd值 ,因而不影响心肌电稳定性 ,提示该组患者早期康复治疗安全可行     

急性心肌梗塞时心前导联QTc离散度对心室颤动的预测作用

目的　探讨急性心肌梗塞时 (AMI) QT间期离散度增加和心室颤动易感性之间的关系。方法　比较分析2 0例 AMI发病后 2 4h内并发心室颤动的患者 (心室颤动组 )和 2 0例未发生心室颤动的 AMI患者 (对照组 )在急诊入院时体表同步 12导心电图的心前 QT间期离散度和 QTc间期离散度。结果　心室颤动组 QTc间期离散度和 QT间期离散度均显著高于对照组 (分别为 70 ms± 30 ms与 32 ms± 15 ms和 6 7ms± 30 ms与 31ms± 17ms,P<0 .0 0 1)。结论　AMI时心前 QT间期离散度增加产生心室颤动的危险性增加     

老年原发性高血压患者血压晨峰现象与左心室肥厚的关系

目的研究老年原发性高血压患者血压晨峰现象,明确血压的晨峰现象与左心室肥厚的关系。方法采用24小时动态血压监测分析仪分析120例老年高血压患者的血压,晨峰组（MBPS）48例,非晨峰组（NMBPS）72例,计算患者的高血压病程、体质量指数（BMI）,常规检查空腹总胆固醇（TC）、甘油三酯（TG）、高密度脂蛋白胆固醇（HDL-C）、低密度脂蛋白胆固醇（LDL-C）、空腹血糖（FPG）,通过心电图计算QT间期、校正的QT间期（QTc）、QT离散度（QTd）和校正的QT离散度（QTcd）、左心室质量指数（LVMI）。结果两组患者之间的BMI、TC、TG、HDL-C、LDL-C、Cr和FPG差异无统计学意义。MBPS组的高血压病程为（24.1±6.2）年,NMBPS组为（16.2±3.4）年,差异有统计学意义（P〈0.01）;MBPS组的LVMI为（169.3±15.9）g/m2,NMBPS组为（138.2±10.8）g/m2,差异有统计学意义（P〈0.05）。MBPS组的QT、QTc、QTd、QTcd分别为（368.3±22.8）ms、（408.7±25.1）ms、（34.6±9.2）ms（、39.1±10.7）ms,NMBPS组的QT、QTc、QTd、QTcd分别为（321.4±14.9）ms、（381.4±18.2）ms、（29.8±8.6）ms、（36.1±9.7）ms,MBPS组的这些指标显著高于NMBPS组（P〈0.01）。结论老年原发性高血压有晨峰现象者更易发生左心室肥厚。     

食管心房超速负荷试验中QT间期离散度变化对冠心病的诊断价值

目的探讨食管心房超速负荷试验的QT间期离散度 (QTd)对冠心病的诊断价值。方法对冠脉造影确诊为冠心病 38例及冠脉造影正常 4 0例进行食管心房超速负荷试验 ,记录试验前后 12导联心电图 ,测量ST段 ,校正QTc及QTd ,利用四格表法 ,分别计算各指标的特异性及敏感性。结果冠心病组试验后QTc及QTd均较试验前明显延长 (P<0 .0 1) ,试验后冠心病组QTd也长于非冠心病组 (P <0 .0 5 )。ST段 ,QTc及QTd诊断冠心病的特异性分别为 95 % ,6 7.5 % ,87.5 % ,敏感性分别为 5 2 .6 % ,73.7% ,84 .2 %。结论食管心房超速负荷试验的QT间期离散度 (QTd)能增加冠心病的诊断敏感度 ,对冠心病具有较高的诊断价值。     

连续性静-静脉血液滤过患者QT间期离散度的临床意义

目的 研究连续性静-静脉血液滤过(CVVH)的患者(原无明确心脏病病史)QT间期离散度(QTd)测定的临床意义.方法 选择ICU内进行CVVH治疗的危重患者,于血液滤过前及血液滤过后6、12、24 h、其后每天描记12导联心电图,并计算平均QTd值.检出心律失常者30例为研究组,另选30例未检出心律失常者设为对照组.结果 研究组滤过前QTd和QTcd的值分别是(48.30±18.52)ms和(22.72±9.16)ms,滤过后QTd和QTcd的值分别是(63.26±20.48)ms和(27.36±10.06)ms;对照组滤过前QTd和QTcd的值是(49.62±13.18)ms和(23.04±7.92)ms,对照组滤过后QTd和QTcd的值分别是(48.86±13.06)ms和(22.87±7.89)ms.研究组QTd明显高于对照组(P＜0.01),差异有统计学意义.结论 CVVH后发生心律失常组(研究组)QTd明显延长,因此,监测QTd的变化应用于连续性CVVH危重患者心脏不良事件的预测,是早期用药,预防心脏严重情况发生的有效手段之一.     

心肌梗死合并糖尿病患者QT间期和QT离散度的改变及不同治疗方法对其的影响

目的 比较心肌梗死后合并糖尿病及未合并糖尿病患者的QT间期(QTc)及QT离散度(QTcd),并比较心肌梗死后糖尿病患者分别用胰岛素、磺脲类药物、双胍类及饮食控制后的QTc、QTcd.方法 138例心肌梗死后患者分为糖尿病组(70例)及非糖尿病组(68例),行同步12导联心电图,测定QTc及QTcd.糖尿病组分别给予胰岛素、磺脲类药物、双胍类及饮食控制后测定QTc及QTcd.结果 糖尿病组的QTc、QTcd显著高于非糖尿病组[(377.2±24.3)ms与(342.9±27.5)ms、(48.8±19.7)ms与(40.3±26.6)ms,t分别为7.77、2.14,P<0.01或0.05],双胍类药物组与饮食控制组QTc、QTcd比较差异无统计学意义(P均>0.05),胰岛素组QTc、QTcd显著高于其他3组(P<0.05或0.01),磺脲类药物组QTc、QTcd高于双胍类药物组及饮食控制组(P<0.05或0.01).结论 心肌梗死后糖尿病患者QTcd增加,提示心肌梗死后糖尿病患者的病死率高.胰岛素和格列吡嗪可能会增加心肌梗死后糖尿病患者QTcd,且在胰岛素治疗后更明显.     

糖尿病OT离散度改变及与心脏植物神经病变关系探讨

目的 :探讨糖尿病患者QT离散度 (QTd)改变及与糖尿病植物神经病变和室性心律失常间的关系。方法 :用同步 12导联心电图测定 6 9例糖尿病患者的QTd、最大QT间期 (QTmax)和经心率校正的QTmax (QTc max) ,同时用Holter监测其心率变异性 (HRV)和室性心律失常发生率 ,并与 6 1例非糖尿病人进行对比分析。结果 :①糖尿病组QTd较非糖尿病组显著增加 (P <0 0 1) ;②糖尿病组心率变异性指标中正常RR间期的标准差(SDNN)、每 5分钟正常间期标准差的平均值 (SDNN -index)较非糖尿病组显著降低 (P <0 0 5 )。糖尿病组QTd与每 5分钟正常RR间期平均值标准差 (SDANN)、SDNN -index存在明显相关性 (P <0 0 5 )。③糖尿病组QTd与室性心律失常存在着明显的正相关 ,而非糖尿病组QTd与室性心律失常的发生无明显相关性。结论 :糖尿病组QTd较非糖尿病组延长 ,且QTd与植物神经病变和室性心律失常相关 ,QTd可作为预测糖尿病患者发生恶性室性心律失常的有用指标。     

肥厚型心肌病QT离散度的临床意义及卡维地洛对其作用

目的探讨肥厚型心肌病QT离散度的临床意义及卡维地洛对其的作用。方法入选48例患者,根据超声结果将患者分梗阻性20例（梗阻组）争非梗阻28例（非梗阻组）,正常对照组20例。为每个患者记录体表常规12导联同步心电图,分别计算QT、QT离散度（QTd）、校正的QT离散度（QTcd）。在治疗过程中给予卡维地洛,在给药前、1个月和3个月后复查以上指标。结果梗阻性肥厚型心肌病和非梗阻性肥厚型心肌病QT、QTd、QTcd均超过正常值（P〈0.01）;卡维地洛能明显缩短两组的QTd,且梗阻组QTd的变化程度较非梗阻组更显著,用药前（84.2±27.1）ms vs（46.5±20.7）ms,用药3个月后（49.8±19.2）ms vs（41.3±16.3）ms（P〈0.05或〈0.01）。结论两组肥厚型心肌病QT、QTd、QTcd均超过正常值,卡维地洛能明显缩短两组的QTd,且梗阻组QTd的变化程度较非梗阻组更显著,有利于改善患者预后。     

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.