射频消融治疗房室结折返和房室折返性心动过速

目的：总结射频消融(RFCA)治疗房室结折返性心动过速和房窒折返性心动过速的经验。方法：分析67例阵发性室上性心律失常病人的RFCA过程；房室结折返性心动过速(AVNRT)49例，房室折返性心动过速(AVRT)18侧。结果：消融成功率98．5％，复发率1．5％，并发症发生率2．98％。结论：RFCA是治疗AVNRT和AVRT安全有效的方法。     

房室结三径路食管心房调搏诱发房室结折近性心动过速

房室结三径路伴房室结折返性心动过速(AVNRT)的临床报道不多见。如果每条经路都能双向传导,理论上三径路者可有6种类型的AV-—RT,而实际发生的大多为慢快型。本文分析15例房室结三径路,食管心房调搏诱发AVNRT的机制及电生理特点。 1 资料和方法 对象为10余年来因心悸及快速心律失常而行食管电生理检查诊断为房室结三径路者,检查前停用各种抗心律失常药5个半衰期以上。按常规食管电生理检查方法进行,如果S_1S_2或S_1S_2S_3法不能显示三径路或诱发AVNRT,则给阿托品2mg静注后再重复以上检查。     

几种特殊慢-快型房室结折返性心动过速的射频消融

房室结折返性心动过速 (AVNRT)是常见的室上性心动过速 (SVT)约占 PSVT40 %～ 5 0 % ,其解剖和生理基础是心房肌与房室结之间移行细胞区各向异性传导 ,形成房室结双径路 (DAVNP) ,消除 DAVNP中任何一条均可阻断房室结内折返环 ,达到根治目的 [1 ]。目前用导管射频电消融 (RFCA)阻断慢径传导治疗典型 AVNRT的方法已经成熟 ,但是对一些特殊情况下的 AVNRT进行 RFCA尚缺乏经验 ,本文对几种特殊慢 -快型 AVNRT的慢径消融作一概述。1　几种特殊类型慢 -快型 AVNRT的特点及消融方法1.1　长 PR的 AVNRT　 DAVNP中少部分患…     

射频消融房室结改良术降低房室结折返性心动过速复发的研究

对房室结双径路并反复发作房室结折返性心动过速(AVNRT)者行射频消融房室结改良术已获普遍认同,但术后存在不同程度的复发率。我们在实践中发现通过彻底消融慢径可以达到减少或消除术后复发AVNRT,同时避免发生房室传导阻滞的目的,现报告如下。 1 资料与方法 1.1 病例选择 200例曾有反复AVNRT史的患者,男性76例,女性124例。将其分为A、B两组,前150例为A组,男性54例,女性96例,年龄(49.0±12.8)岁,后50例为B组,男性22例,女性28例,年龄(48.2±14.3)岁。术前停用所有抗心律失常药物至少72小时,术前、术中均不用镇静药物。     

房室结折返性和房室折返性心动过速的对比研究

【目的】探讨房室结折返和房室折返性心动过速（AVNRT,AVRT）的特点及射频消融（RFCA）的疗效和安全性。【方法】回顾性分析本院近6年行RFCA的823例AVNRT和AVRT患者的临床和电生理特点及手术情况。【结果】AVRT较AVNRT多见．AVNRT女性多于男性,而AVRT男性多见（P〈0．01）。AVRT中左侧较右侧旁路多见。左侧旁路以隐匿性为主．而右侧旁路以显性为主（P〈0．01）;左侧旁路男性多见,而右侧旁路以女性为主（P〈0．01）。右侧显性旁路手术成功率明显低于其他旁路和AVNRT（P〈0．05和P〈0．01）．术后复发率明显高于左侧旁路（P〈0．05和P〈0．01）。2例AVNRT术后出现房室传导阻滞而植入心脏起搏器,发生气胸和血气胸6例。心包填塞1例．假性动脉瘤3例,1例左侧旁路放电时出现心室纤颤。无一例患者死亡。【结论】AVNRT和AVRT消融手术成功率高而复发率低．严重并发症较少．RFCA治疗AVNRT和AVRT是有效和安全的。     

房室结双径路消融中特殊电生理现象分析与处理

目的 :分析房室结折返性心动过速 (AVNRT)慢径路消融中特殊电生理现象及处理体会。方法 :慢径路消融前常规行心内电生理检查。结果 :有特殊电生理现象者 8例 ,其中 3例患者AVNRT开始时表现为房室 2 :1传导 ,阻滞点在希氏束以上部位 ;3例患者房室结功能曲线呈连续性 ;1例为慢 -慢型AVNRT ;1例心内电生理检查未能诱发出AVNRT。所有患者慢径消融均成功。结论 :术前应行详细的心内电生理检查和仔细鉴别 ,其消融方法与典型AVNRT相同     

无明显跳跃现象的房室结双径路1例

本文报告 1例经心内电生理检查证实心动过速为慢 -快型房室结折返性心动过速 (S- F型 AVNRT) ,并经射频消融(RFCA)根治成功 ,但术前及术中的程序期前刺激 (S1、S2 ) ,均未诱发出房室结传导的跳跃现象。1　病历简介女 ,70岁。因阵发性室上性心动过速 (PSVT)反复发作 3年入院。查体 :心脏 B型超声波及 X射线胸片检查 ,心脏结构和功能正常。食道电生理检查 S1、S2刺激能诱发终止 PSVT,但未见房室传导时间跳跃 ,食道调搏结果提示隐匿性旁道。为根治 PSVT做 RFCA,经右颈内静脉 ,左、右股静脉穿刺插入4根标测电极分别置于冠状窦、希…     

房室结双径路伴房室结折返性心动过速的室房传导探讨

根据电生理检查结果,将接受射频消融术患者62例分为房室旁道伴房室折返性心动过速(AVRT)32例,房室结双径路(DAVNP)伴房室结折返性心动过速(AVNRT)30例。以房室旁道伴AVRT室房(VA)传导特征为对照,探讨DAVNP伴AVNRT VA传导特征。结果表明DAVNP伴AVNRT其VA传导发生率为100％;室房逆传多经房室结快径;快径逆传具有房室旁道逆传特征。     

房室结双径路消融中特殊电生理现象分析与处理

目的：分析房室结折返性心动过速（AVNRT）慢径路消融中特殊电生理现象及处理体会。方法：慢径路消融前常规行心内电生理检查。结果：有特殊电生理现象者8例，其中3例患者AVNRT开始时表现为房室2：1传导，阻滞点在希氏束以上部位；3例患者房室结功能曲线呈连续性；1例为慢-慢型AVNRT；1例心内电生理检查未能诱发出AVNRT。所有患者慢径消融均成功，结论：术前应行详细的心内电生理检查和仔细鉴别，其消融方法与典型AVNRT相同。     

房室结多径路的射频消融治疗

阵发性心动过速是临床上最常见的心律失常之一，其机制主要以房室结折返(AVNRT)或房室折返性(AVRT)等较常见，其它类型较少见。其中AVNRT由多径路同时存在国内文献报道极少。我们在临床心脏电生理检查和射频消融术(RFCA)中发现62例，现报告如下。     

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.