Atrial Synchronous Ventricular Pacing with a Single Lead: Reliability of Atrial Sensing During Physical Activities, and Long-term Stability of Atrial Sensing

A VDD pacing system with bipolar single-pass leads, were implanted in 36 consecutive patients (average age 72 ± 2years) with high degree atrioventricular block and normal sinus node function. At implant the atrial signal amplitude was 2.6 ± 0.2mV measured by a pacing system analyser (PSA), 1.8 ± 0.1mV measured peak-to-peak from the telemetered calibrated electrogram, and 1.3 ± 0.1mV measured from the sensing threshold. At one month follow-up the peak-to-peak amplitudes (mV) of the telemetered atrial electrograms were not significantly different measured continuously during resting supine with quiet breathing (1.4 ± 0.1), sitting (1.6 ± 0.2). standing (1.5 ± 0.1), arm swinging (1.4 ± 0.2), hyperventilation (1.3 ± 0.1), Vaisalva manoeuvre (1.4 ± 0.1), and treadmill exercise (1.9 ± 0.6). The telemetered atrial electrogram amplitude and the atrial sensing threshold varied between 1.2 ± 0.09mV and 1.8 ± 0.1mV, and between 0.95 ± 0.07mV and 1.3 ± 0.01mV, respectively at 0.5, 1, 3, 6 and 12 months follow-up, but the changes were statistically nonsignificant. The Event Summary showed sensing of 98% to 99% of the atrial events at the different follow-up periods.     

非瓣膜病房颤患者左心耳血流动力学的TEE研究

应用多平面经食管超声心动图技术（Ｍ－ＴＥＥ），对３０例健康人和３０例非瓣病房颤患者（ＮＶＡＦ）心底短轴切面测量了左心耳最大直径，同一心动周期内左心耳最大及最小面积及左心耳最大空速度，产将ＮＶＡＦ患者按照自发显影及血栓的有无分为２组。发现ＮＶＡＦ组左心耳增大，收缩力及血流速度均减低，且这种变化在有血栓和有血栓形成倾向的患者中更为明显。     

Atypical Form of the Fourth Criterion for Transient Entrainment

The typical fourth criterion for transient entrainment is defined when both a sudden shortening in conduction interval to and a distinct change in electrogram morphology at a bipolar recording site are demonstrated while performing overdrive pacing of a reentrant tachycardia from a single pacing site at two different constant rates. The purpose of this article was to test the hypothesis that if an intracardiac recording site showing both orthodromic and antidromic capture with entrainment pacing is located suitably distant from the circuit, sudden shortening in conduction interval to that site may occur without any significant change in the bipolar electrogram morphology (i.e., atypical form of the fourth criterion). Atrial overdrive pacing of orthodromic tachycardia was performed in 20 patients with either left anterior (12 patients) or left posterior (8 patients) accessory pathways. We investigated the effects of overdrive pacing from the proximal or distal coronary sinus, specifically effects on the electrogram interval and the electrogram morphology at the right atrial appendage. Overdrive pacing of orthodromic tachycardia from the proximal coronary sinus was performed in 10 of the 12 patients with left anterior accessory pathways; those 10 patients demonstrated the first entrainment criterion at the right atrial appendage site. Overdrive pacing of orthodromic tachycardia at still shorter cycle lengths demonstrated a sudden shortening in conduction interval to the right atrial appendage site. Despite shortening in conduction interval the morphology of the right atrial appendage electrogram was completely or almost identical to that during orthodromic tachycardia, indicating an atypical form of the fourth criterion. This criterion was not demonstrated in patients with left posterior accessory pathways. Thus, atypical fourth entrainment criterion was demonstrated during overdrive pacing of orthodromic tachycardia from the proximal coronary sinus only in patients with left anterior accessory path ways. Demonstration of atypical fourth criterion seems largely dependent on the location of the accessory pathway, the pacing, and the recording sites.     

房间隔入路的解剖学研究及临床应用

对３３具尸体的房间隔的大小、构成及周围重要组织结构进行观察和测量。提出房间隔切开时的正确方向、安全长度及可能发生的危险。结合４６６例临床应用，讨论了避免切口合并症发生及发生后的正确处理方法。     

足组织缺损的显微修复

１９８４年～１９９４年共收治各种足部组织创伤缺损２３６例，均采用显微外科技术进行组织移植修复，其中单纯皮瓣移植修复１８７例，复合皮瓣移植修复４９例。吻合血管游离移植修复９７例，带血管蒂移位修复１３９例。４例前足缺损者用带肩胛骨的复合皮瓣移植修复，６例足跟严重缺损者用带血管的腓骨复合皮瓣移植修复。经１～１０年随访，皮瓣、复合皮瓣、移植或再植的骨骨各全部成活，愈合良好，足功能基本得到恢复，可行走、负重，１８６例恢复了原工作。认为，恢复足部结构完整与重建足跟、足底的感觉是获得良好功能的关键     

腰椎峡部裂的CT诊断

目的：回顾性分析腰椎峡部裂的ＣＴ表现并讨论其诊断与鉴别诊断，材料与方法，２３例患先行腰椎侧位扫描定位图像，采用与椎间盘平行的角度，自病变脊椎的上一椎体下缘边续发描至于下椎体上缘，层厚４或５ｍｍ必要时在峡部行２ｍｍ，层厚扫描，结果；２３例中，累及双侧２１例，单侧２例，发生在Ｌ５１６例，Ｌ４７例，ＣＴ表现为同一脊椎关节突间的低密度裂隙，出瑞椎弓根下缘平面，走行不规则，裂隙可宽可窄，表面不光滑。     

Cytoprotective actions of 2,4-dimethoxybenzylidene anabaseine in differentiated PC12 cells and septal cholinergic neurons

The potential cytoprotective actions of a novel nicotinic agent 2,4-dimethoxybenzilidene anabaseine (DMXB) were investigated in differentiated PC12 cells and transected rat septal cholinergic neurons in vivo. In NGF-differentiated PC12 cells, removal of both NGF and serum led to cell loss, a reduced % of cells expressing neurites, the release of lactate dehydrogenase, and a decrease in total cellular protein. Cell loss was apparent within 24 h, and remained constant between 4–8 days post-NGF removal. NGF alone (100 ng/ml), DMXB (10 μM), but not nicotine (10 μM), prevented these cell and neurite losses. DMXB-induced cytoprotection was blocked by 1 μM mecamylamine. DMXB (1 mg/kg, ip) injected twice but not once per day protected cholinesterase-staining septal neurons from retrograde degeneration following unilateral fimbrial transections. The twice per day DMXB injection-protocol also decreased cell roundness among cholinesterase-staining cells in the lesioned septal hemisphere compared to saline-injected animals. These studies suggest that DMXB may exert cytoprotective activity in NGF-sensitive neuronal populations. © 1994 Wiley-Liss, Inc.     

骨水泥和种植体同期植入修复颌骨和牙列缺损的实验研究

目的：探讨高分子材料和种植体同期植入缺损区进行同步骨缺损修复和牙列缺损修复的可行性。方法：以4只杂种狗为研究对象，制备下颌骨长约2．5cm的缺损的动物模型(保留下颌骨下缘)，将骨水泥(聚甲基丙烯酸酯)植入骨缺损，同时将牙种植体植入骨水泥中并调整长轴方向，立即关闭术创。至术后3个月摄X线片，然后处死动物，局部巨检以了解骨水泥同骨组织的结合情况，并制备骨组织切片进行苏木精一伊红染色和甲苯胺蓝染色，以了解植入材料周边骨的生长情况及其对植入材料的反应。结果：术后3个月X线检查见骨缺损区充满骨水泥，骨水泥周边的骨小梁清晰，未见骨吸收或炎症表现，形成良好的骨-骨水泥界面，种植体则依赖其表面的螺纹结构与骨水泥间紧密的机械性嵌合而牢固的成为一体，植入的骨水泥块与周边天然骨结合紧密，无松动现象。植入材料周边局部脱钙骨的苏木精-伊红染色和甲苯胺蓝染色见骨结构正常，同时骨-骨水泥界有新骨形成。结论：骨水泥作为颌骨修复替代材料同期植入种植体是可行的。     

球囊二尖瓣扩张术后心房纤颤复律的临床研究

目的探讨二尖瓣狭窄合并心房纤颤患者在球囊二尖瓣扩张后,转复心房纤颤的临床效果及影响心房纤颤转复后窦性心律维持的相关因素.方法 206例二尖瓣狭窄合并心房纤颤患者在球囊扩张术后,采用口服胺碘酮及电复律治疗心房纤颤,对复律成功的患者给予小剂量胺碘酮维持窦性心律并随访1年.结果服用胺碘酮者58例,17例转复成功(29.3%);189例行电转复,178例转复成功(94.2%),电转复成功率明显高于胺碘酮转复(P＜0.01).心房纤颤复发组与保持窦性心律组相比,左心房内径明显扩大(P＜0.01),心房纤颤持续时间明显长(P＜0.01),中度二尖瓣关闭不全人数的比率明显高(P＜0.05).随访1年,有45例患者心房纤颤复发.影响心房纤颤转复后维持窦性心律的相关因素有左心房内径扩大、心房纤颤持续时间长及明显的二尖瓣关闭不全.结论对左心房内径明显扩大、心房纤颤持续时间过长及有明显的二尖瓣关闭不全的患者,在选择心房纤颤转复时应慎重.     

PRENATAL DIAGNOSIS Ⅰ. EARLY DIAGNOSIS OF OPEN NEURAL TUBE DEFECTS BY QUALITATIVE ACETYLCHOLINESTERASE ISOENZYME IN AMNIOTIC FLUID

The measurement of amniotic fluid (AF) acetylcholinesterase isoenzyme (AChEI) is a relatively new method for early diagnosis of open neural tube defects (NTDs). As quantitative methods are of unproven reliability at present, the authors used a high resolving power qualitative method-vertical slab polyaerylamide gel electrophoresis. The benefits of this technique are: simplicity of operation, accuracy, unsophisticated equipment, and easily available reagents. Combined results of 9 NTDs studies revealed that samples from early pregnancy gave more accurate results than those from late pregnancy.