Regional left atrial voltage in patients with atrial fibrillation

BACKGROUND: Regional differences in fibrosis, particularly related to the posterior wall and septum, may be important in atrial fibrillation (AF). Using electroanatomic mapping, voltage can be used as a measure of fibrosis. OBJECTIVES: The purpose of this study was to determine if patients with AF have disproportionately lower voltage in the septal and posterior walls of the left atrium. METHODS: Sinus rhythm left atrial electroanatomic maps were used in serial patients presenting for left atrial ablation of AF (8-mm tip). Patients undergoing left atrial mapping for focal atrial tachycardia (AT) were used as a comparison group (4-mm tip). Animal experiments were performed to assess the influence of ablation catheter tip size on voltage amplitude. RESULTS: The posterior and septal walls exhibited the lowest voltages in both groups. Compared with the anterior wall, there was a 3.78-fold greater odds of finding a low-voltage point (<0.5 mV) in the septum (P <.001) and a 3.37-fold greater odds of finding a low-voltage point in the posterior wall (P <.001) in the AF patients; the proportion of low-voltage points by region were not significantly different in the AT group. In the animal model, the mean voltage obtained from an 8-mm ablation catheter was significantly higher (0.30 +/- 0.17 mV) than that obtained from the same points using a 4-mm catheter (0.22 +/- 0.17, P = .05). CONCLUSION: Regional differences in voltage are present in patients with atrial arrhythmias, with AF patients exhibiting significantly more low-voltage areas in the septum and posterior walls.     

全麻复合硬膜外阻滞与单纯全麻的比较

比较全麻复合硬膜外阻滞和单纯全麻在围术期对机体应激、炎性、免疫等方面的影响。使用全麻加硬膜外麻醉能有效地抑制手术引起的应激反应，稳定循环状态，减少并发症，使病人在术中更为安全平稳，麻醉效果更为可靠，术毕清醒快，术后镇痛有利于术后病人咳嗽咯痰，并且能减轻围手术期对T细胞亚群的影响。     

角蛋白人工腱膜预防全椎板切除术后硬脊膜黏连

[目的]探讨角蛋白（keratinsubstance，KS）人工腱膜材料用于预防全椎板切除术后硬脊膜黏连的效果。[方法]Wistar大白鼠60只，随机分3组，每组20只，咬除T。：全椎板，造成2rnrnX8rnlffl大小的椎板缺损，加入不同处理因素，A组：空白对照组；B组：人工腱膜组；C组：白体腱膜组。术后2、4、8，12周处死动物，各时间点大体观察采用Rydell瘢痕黏连程度评级标准评分。完整取出T。：节段，包括椎旁肌。经HE染色后，镜下组织学观察采用改良Nussbaum标准行评分。同时切取2，4、8、12周人工腱膜组硬膜外瘢痕组织进行透射电镜观察。所测数据行Kruskal—Wallis秩和检验，取a〈0．05作为统计显著差异的标准。[结果]KS人工腱膜材料无毒性和排异反应：A组的Rydell评分，改良Nussbaum评分高于B、C组（P〈0．05），B组C组比较无差别（P〉0．05）。B、C组与对照组比较，均能够明显减少椎板切除术后的硬膜外瘢痕形成。[结论]硬膜外瘢痕黏连主要来自硬膜后方的血肿和成纤维细胞（fibroblast，FB）的增殖。KS人工腱膜具有良好的组织相容性，无局部及全身的不良反应，具有良好物理屏障作用。将l（S人工腱膜放置在椎板缺损处，能够有效的防止纤维组织侵入椎管，预防硬膜外瘢痕黏连。在动物实验中，KS人工腱膜能够安全有效的预防椎板切除术后硬膜外瘢痕黏连。     

重度慢阻肺病人静脉留置针封管液浓度的选择

目的研究不同剂量肝素在重度慢阻肺病人静脉留置针的封管效果。方法300例重度慢阻肺病人随机分为对照组实验组，各150例，在每次治疗结束后均用3mL肝素盐水正压封管，浓度分别为62．5U／mL、125U／mL。观察并比较2组病人堵管及出血发生情况。结果肝素封管液堵塞的发生率实验组与对照组比较差异有统计学意义（P〈0．01）；实验组与对照组在发生出血情况上差异无统计学意义（P〉0．05）。结论重度慢阻肺病人静脉留置针使用3mL肝素盐水（125U／mL）封管既可减少堵管发生又安全。     

Physiological pharmacokinetics of solutes in the isolated perfused rat hindlimb: Characterization of the physiology with changing perfusate flow,protein content,and temperature using statistical moment analysis

Distribution of Evans Blue (EB), sucrose, and water into the isolated perfused rat hindlimb was studied under various conditions using the multiple indicator dilution (MID) technique. Statistical moment analyses of the outflow profiles for the EB, sucrose, and water were used to define the vascular, extravascular, and total water spaces, respectively. The varied perfusion conditions included albumin content (2, 4.7, and 7%), temperature (25, 37, and 42 C), perfusate flow rate (2, 4, 8, and 12 ml/min) and the presence/absence of red blood cells. The range of studies undertaken were chosen to represent the variety of conditions used in the preparation of both isolated animal and human limbs, the latter being particularly important in cytotoxic therapy for recurrent malignant melanoma. The distribution volumes of EB, sucrose, and water were dependent on the flow rate and the albumin content of perfusate. The normalized variances (CV ² ) of the markers were of the following order: sucrose (2.18) > water (1.58) > EB (0.68), indicating that some disequilibrium occurs during the capillary exchange of water and sucrose. It is suggested that a Krebs-Henseleit buffer containing 2% BSA is a suitable perfusate for most studies of the isolated rat hindlimb perfusion. The effect of albumin concentration manifests itself only at higher flows.We acknowledge the support of the National Heart Foundation (Queensland) and the Mayne Bequest Foundation. This study was conducted while the investigator (Z.Y. Wu) was in receipt of a WHO Research Training Grant. Professor M. S. Roberts also acknowledges the support of the Queensland and Northern New South Wales Lions Kidney & Medical Research Foundation.     

Clinical Recurrences After Successful Accessory Pathway Ablation:

Dormant Accessory Pathways. Introduction : Recurrence of clinical symptoms after radiofrequency catheter ablation of an accessory atrioventricular pathway (AP) may be due to the late manifestation of an additional AP that was not detected during the initial ablation session. It was the purpose of this study to elucidate the phenomenon of these "dormant" APs.
Methods and Results : Of 1280 consecutive patients who underwent radiofrequency catheter ablation of an AP, 54 patients (4.2 %) developed clinical symptoms postablation, necessitating a repeat ablation session. Recurrence of conduction over the AP targeted al the initial ablation session was found in 45 patients, whereas in the other 9 patients (0.7%) the manifestation of a previously unnoticed AP had caused symptom recurrence. Retrospective analysis of the data from these patients' ablation sessions revealed that the late manifesting AP was ablated at a site clearly different from that of the initially targeted AP, and that the manifestation of conduction over a previously "dormant" AP occurred significantly later than the recovery of a presumably ablated AP. Seven (78%) of the 9 "dormant" APs were concealed, and none exhibited decremental conduction properties.
Conclusion : The incidence of clinical recurrences mediated by the late manifestation of conduction over a previously "dormant" AP is low. The lack of an anatomic vicinity of these predominantly concealed APs with the initially targeted AP and the lack of evidence for their presence during the initial ablation session suggest intermittent conduction as the most likely explanation for their late manifestation.     

电针改善硬膜外吗啡用于术后镇痛所引起的免疫抑制

为观察硬膜外吗啡和电针对术后患者免疫功能的影响，检测自然杀伤细胞（ＮＫｃｅｌｌ）活性和ＰＨＡ诱导白细胞介素２（ＩＬ－２）水平在单纯胆囊切除术患者术前和术后第１、３、７天的动态变化情况。结果吗啡组ＮＫ活性在术后第１、３、７天抑制，手术组仅在术后第１、３天出现抑制，而抑制率低于同天的吗啡组，电针可拮抗吗啡引起的ＮＫ活性抑制加深状况。在术后第１天，手术组和吗啡组ＩＬ－２水平均下降，吗啡＋电针组无明显变化，术后第７天吗啡＋电针组ＩＬ－２升高接近正常人水平。表明电针能改善硬膜外吗啡引起的免疫抑制，促进术后机体的恢复。硬膜外吗啡结合电针是值得推荐的术后镇痛方法。     

The CT criteria for conservative treatment — but under close clinical observation — of posterior fossa epidural haematomas

Summary In order to assess whether the indications for conservative treatment of supratentorial epidural haematomas are applicable also to posterior fossa epidural haematomas (PFEDH), the author reviewed the records of 25 patients. With a PFEDH volume of no more than 10 ml, a thickness of no more than 15 mm, a midline shift of no more than 5 mm, and in the absence of a significant intracranial haematoma elsewhere on computed tomography (CT) scans, the patients undergoing conservative treatment achieved the same excellent outcome as those undergoing early surgery. These CT criteria for conservative treatment of PFEDHs are similar to those of supratentorial epidural haematomas except the volume factor, namely, 10 ml in the former against 30 ml in the latter. That means a PFEDH of 10 ml or larger in the small posterior fossa may produce the same degree of midline shift and compression, and be as dangerous as an epidural haematoma of 30 ml or larger in the more capacious supratentorial compartment. But also for epidural haematomas of the posterior fossa, which initially are smaller than 10 ml, the general rule remains valid that they should be under close clinical supervision     

Experimental study of spinal cord compression by epidural tumors using electron probe X-ray microanalysis and confocal laser scanning microscopy

Changes in the nerve fibers of the spinal cord were studied in rat experimental epidural tumor models. Light microscopy showed demyelinization in all with rats paraparesis and paraplegia. Cross-sectional views of nerve fibers stained with 3,3dipentyloxacarbo-cyanine iodide, obtained by confocal laser scanning microscopy, showed distorted, shrunken fibers with a low fluorescence intensity. Changes in the electrolyte contents of nerve fibers were studied by electron probe X-ray microanalysis. The K concentration in axons and the myelin sheath was increased in the paraparesis group, but was decreased in the paraplegia group. These findings suggest that, in the paraparesis group, compression of the spinal cord damaged cell membrane channels, which subsequently caused an increase in intracellular K, a decline in the action potential, and low-intensity fluorescence of nerve fibers. On the other hand, in the paraplegia group, destruction of cell membranes caused a decrease in intracellular K until it approached the extracellular level. This reduced both the action potential and the fluorescence intensity. As Ca and Mg concentrations in both axons and the myelin sheath increased in relation to the severity of neurologic damage, it appears that these electrolytes may also play an important role in damage to nerve fibers.