同时测定心室易损期和室颤阈评价心室易损性的方法学探讨

室颤阈的降低和心室易损期的延长是判断心室易损性的标志,目前大多数研究仅以室颤阈作为指标,对易损期的研究极少,且把两者     

实验性心室纤颤时在位心脏心室肌动作电位的特性

自从用电刺激心脏易损期引起实验性心室纤颤(室颤)的首次报道以来,已有大量工作。室颤时心电图的特征已为众所熟知,但在单个细胞上记录此时动作电位的变化,则只有很少的报道。所得结果也不完全一致。 迄今为止,关于室颤的发生,一般归因于多发折返机制。然而近年来对Purkinje纤维及心室肌细胞的异常节律性活动的研究有了很大进展,因而,异位灶快速发放的机制,又得到重视。我们实验室近年来发现,在某些条件下,单个电刺激作用于心室肌动作电位复极(3相)早期,可能发出一系列快速去极化波。     

α和β受体阻断剂对麻醉大鼠室颤阈值的影响

心室纤颤是心脏病患者猝死的主要原因。关于交感神经兴奋使室颤阈降低的受体机制以及α和β受体激动在室颤发生中的相对重要性,仍在争论。因此阐明影响室颤的各种因素和设法提高室颤阈,对防治室颤所致猝死具有重要意义。本文报道α和β受体阻断剂对麻醉大鼠心脏电刺激致颤影响的初步探讨。     

家兔急性心肌缺血室颤阈的动态变化

急性心肌缺血早期发生室颤是致死的重要原因之一。室颤阈(VFT)的测定是了解心电活动的重要手段。VFT的测定国外多在大动物心脏上进行。国内这方面工作较少,在国内多采用连续性方波刺激法,刺激的时间长,损伤大。我们利用家兔冠脉左室枝结扎造成急性心肌缺血,以分频式、R波触发易损期刺激法测定VFT,观察急性心肌缺血两小时内VFT的动态变化,可作为室颤防治研究提供实验依据。     

卡托普利对兔急性心肌梗塞早期再灌注心室肌易损性的影响

目的：观察卡托普利对兔急性心肌梗塞（AMI）早期再灌注心室易损性的改变，探讨卡托普利对AMI早期再灌注心律失常的影响。方法：采用S1-S2程控电刺激方法同时测定开胸不阻断冠脉的无心肌缺血组（假手术对照组）、无心肌缺血用卡托普利灌流组（卡托普利组）、AMI早期缺血-再灌注对照组（再灌注对照组）和用卡托普利灌流早期缺血-再灌注组（再灌注卡托普利组）对家兔心室易损期（VVP）、室颤阈（VFT）、舒张阈（DT）、有效不应期（ERP）、T波顶点与VVP外缘处的时间关系（T_T-VVP）等电生理指标，卡托普利灌流速度0.1 mg·kg^-1·min^-1。结果：VVP、VFT、DT、ERP和T_T-VVP在假手术对照组和卡托普利组分别为(8.12±2.43) ms、(2.49±0.76) μJ、(3.62±0.59) V、(178.67±16.43) ms、(51.32±8.76) ms和(8.64±2.85) ms、(2.41±0.80) μJ、(3.85±0.58) V、(180.25±14.87) ms、(50.35±8.91) ms，组间比较皆无显著差异（P>0.05），再灌注对照组分别为(85.37±20.65) ms、(0.16±0.13) μJ、(2.25±0.48) V、(112.65±13.61) ms和(10.72±4.81) ms，再灌注卡托普利组分别为(56.34±15.21) ms、(0.26±0.14) μJ、(2.91±0.61) V、(137.83±15.24) ms和(14.84±7.89) ms；假手术对照组与再灌注对照组和再灌注卡托普利组比较有显著差异（P<0.01），再灌注对照组与再灌注卡托普利组比较亦有显著差异（P<0.01）。结论：卡托普利对无缺血心肌影响不明显；缺血-再灌注能明显增加急性心肌梗塞早期再灌注室性心动过速和/或心室颤动的发生，卡托普利对再灌注室性心动过速和/或心室颤动的发生有抑制作用。     

丹参对家兔急性缺血及再灌注心肌易损期和不应期的影响

本文采用程序性电刺激测定家兔心室易损期（VVP）和有效不应期（ERP）,观察了丹参对缺血和再灌注心肌的保护作用。结果表明,急性心肌缺血（AMI）和再灌注时,丹参组动物VVP明显低于对照组（分别P＜0．05及0．01）,ERP有所延长,但仅在再灌时明显大于对照组（P＜0．05）;AMI时的室颤（VF）发生率明显低于对照组（P＜0．01）,上述结果提示丹参可减轻缺血及再灌注损伤所致的心肌电生理改变,从而降低心肌的易损性。     

心尖搏动图正常参考值

【P-a间期】自心电图(ECG)的P波始点至心尖搏动图(ACG)的a波始点之间期,表示心房电-机械延迟时间,正常值80~100ms。【a-C间期】亦称房波间期,自a波始点至C点之间期,表示房缩时间(AST),正常值40~100ms,延长者揭示左室舒张末压升高。【Q-C间期】自ECG的QRS波始点至ACG的C点之间期,表示心室电-机械延迟时间(EML),正常值60.5±9.8ms,冠心病、二尖瓣狭窄者多延长。【C-A2间期】自ACG的C点至心音图(PCG)的第二心音主动脉瓣关闭成分之间期,表示心室收缩期(MST),正常值320~360ms。【Q-S2间期】自ECG的QRS波始点至PCG的第二心音…     

心室复极化时程的变异及心室复极化时程对RR间期依赖性 …

心室复极化时程作为反映心室除极和复极时间的重要的电生理参数，越来越受到关注。它受到许多生理和病理因素的影响，在许多心脏疾病中它表现出明显的特征。我们研究了正常人不同年龄组以及正常人和心脏病人心室复极化时程变异（ＲｅｐｏｌａｒｉｚａｔｉｏｎＤｕｒａｔｉｏｎ Ｖａｒｌａｂｉｌｉｔｙ，ＲＤＶ）和心室复极化时程对ＲＲ间期（ＲＴｍ对ＲＲ）依赖性的变化规律。从我们的实验结果看到ＲＤＶ和ＲＴｍ对ＲＲ依赖性指标     

家兔心肌缺血范围对缺血早期室颤阈的影响

观察30只家兔在心率固定情况下，改变缺血范围对心肌缺血早期室颤阈（VFT）、颈动脉血压和血浆去甲肾上腺素含量的影响以及切断双侧迷走神经后，于上述情况下VFT的变化，结果表明改变心肌缺血范围可影响VFT值；但与心率、血压、血浆去甲肾上腺素水平以及迷走神经状态无关 ，提示心肌缺血早期的室颤和缺血范围有关。     

卡托普和对早期急性心肌梗塞后心室扩张及心功能的影响

卡托普和对早期急性心肌梗塞后心室扩张及心功能的影响山东省荷泽地区人民医院（荷泽市２７４０３１）任晓庆，赵新力，吴明永，白明，孙玉琴急性心肌梗塞（ＡＭＩ）早期即可出现梗塞区室壁膨展（ｉｎｆａｒｃｔｅｘｐａｎｓｉｏｎ），继而出现左室重构（ＬＶｒｅｍｏｄｅ...     

钾对再灌流早期室颤阈变化的影响

本实验在69只家兔上比较观察了高钾动脉血、血浆和正常动脉血对局部缺血心肌再灌流早期室颤阈(VFT)变化的影响。实验结果表明,缺血心肌用正常动脉血再灌流可使其VFT在灌流1分内迅速下降,然后逐渐回升。其中氧的恢复和钾的改变对VFT下降程度影响不同。缺血后用血浆再灌流,其VFT下降程度与缺血后用正常动脉血再灌流相比无显著性差异;而用高钾动脉血再灌流比用正常动脉血再灌流VFT下降程度轻(P<0.05)。本实验结果提示,在再灌流心律失常产生中缺血时所积累的钾的突然冲洗和再分布可能起更重要的作用。     

溶栓治疗对急性心肌梗塞患者纤溶系统功能的影响

本文通过观察纤溶系统活性,纤维蛋白原(Fg)、纤维蛋白降解产物(FDP)含量变化,探讨蛇毒抗栓酶(SVATE)、UK溶栓治疗对急性心肌梗塞(AMI)的临床意义。结果表明,静脉一次大剂量UK治疗,患者血浆PL、ELA、t-PA活性和FDP出现快速大幅度增高,PAI、Fg降低、这种作用仅持续短时间、SVATE静脉首次大剂量以后小剂量维持2周处理,血浆上述纤溶指标逐渐恢复,ELA、t-PA和PAI活性2～3周接近正常水平。结果提示,SVATE、UK溶栓治疗使AMI患者纤溶功能得到改善,若采用二者联合用药,效果可能更理想。     

Granulocyte colony-stimulating factor stabilizes cardiac electrophysiology and decreases infarct size during cardiac ischaemic/reperfusion in swine

Aim: Effects of granulocyte colony‐stimulating factor (G‐CSF) on cardiac electrophysiology during ischaemic/reperfusion (I/R) period are unclear. We hypothesized that G‐CSF stabilizes cardiac electrophysiology during I/R injury by prolonging the effective refractory period (ERP), increasing the ventricular fibrillation threshold (VFT) and decreasing the defibrillation threshold (DFT), and that the cardioprotection of G‐CSF is via preventing cardiac mitochondrial dysfunction. Methods: In intact‐heart protocol, pigs were infused with either G‐CSF or vehicle (n = 7 each group) without I/R induction. In I/R protocol, pigs were infused with G‐CSF (0.33 μg kg^?1 min^?1) or vehicle (n = 8 each group) for 30 min prior to a 45‐min left anterior descending artery occlusion and at reperfusion. Diastolic pacing threshold (DPT), ERP, VFT and DFT were determined in all pigs before and during I/R period. Rat’s isolated cardiac mitochondria were used to test the protective effect of G‐CSF (100 nm ) in H₂O₂‐induced mitochondrial oxidative damage. Results: Neither G‐CSF nor vehicle altered any parameter in intact‐heart pigs. During ischaemic period, G‐CSF significantly increased the DPT, ERP and VFT without altering the DFT. During reperfusion, G‐CSF continued to increase the DPT without altering other parameters. The infarct size was significantly decreased in the G‐CSF group, compared to the vehicle. G‐CSF could also prevent cardiac mitochondrial swelling, decrease ROS production, and prevent mitochondrial membrane depolarization. Conclusion: G‐CSF increases the DPT, ERP and VFT and reduces the infarct size, thus stabilizing the myocardial electrophysiology, and preventing fatal arrhythmia during I/R. The protective mechanism could be via its effect in preventing cardiac mitochondrial dysfunction.     

Time trend and age-period-cohort effects on acute myocardial infarction mortality in Korean adults from 1988 to 2007

We examined time trend and age-period-cohort effects on acute myocardial infarction (AMI) mortality in Korean adults from 1988 to 2007. Annual AMI mortality data and population statistics from 1988 to 2007 were obtained from the STATISTICS KOREA website. Age adjusted mortality for four 5-yr calendar periods (1988-1992 to 2003-2007) was calculated by direct standardization using the Year 2000 WHO world standard population. A log-linear Poisson regression model was used to estimate age, period, and cohort effects on AMI mortality. In both genders, age-adjusted AMI mortality increased from period one (1988-1992) to period three (1998-2002) but decreased in period four (2003-2007). An exponential age effect was noted in both genders. The rate ratio of the cohort effect increased up to the 1943 birth cohort and decreased gradually thereafter, and the rate ratio of the period effect increased up to period three (1998-2002) and decreased thereafter. Our results suggest that AMI mortality in Korean adults has decreased since the period 1998-2002 and age, period, and cohort effects have influenced on AMI mortality.     

The vertebral venous plexuses: the internal veins are muscular and external veins have valves

The internal and external vertebral venous plexuses (VVP) extend the length of the vertebral column. Authoritative sources state that these veins are devoid of valves, permitting bidirectional blood flow and facilitating the hematogenous spread of malignant tumors that have venous connections with these plexuses. The aim of this investigation was to identify morphologic features that might influence blood flow in the VVP. The VVP of 12 adult cadavers (seven female, mean age 79.5 years) were examined by macro- and micro-dissection and representative veins removed for histology and immunohistochemistry (smooth muscle antibody staining). A total of 26, mostly bicuspid, valves were identified in 19 of 56 veins (34%) from the external VVP, all orientated to promote blood flow towards the internal VVP. The internal VVP was characterized by four main longitudinal channels with transverse interconnections; the maximum caliber of the longitudinal anterior internal VVP veins was significantly greater than their posterior counterparts (P < 0.001). The luminal architecture of the internal VVP veins was striking, consisting of numerous bridging trabeculae (cords, thin membranes and thick bridges) predominantly within the longitudinal venous channels. Trabeculae were composed of collagen and smooth muscle and also contained numerous small arteries and nerve fibers. A similar internal venous trabecular meshwork is known to exist within the dural venous sinuses of the skull. It may serve to prevent venous overdistension or collapse, to regulate the direction and velocity of venous blood flow, or is possibly involved in thermoregulation or other homeostatic processes.     

卡托普利对家兔急性心肌梗塞早期血小板活化及纤溶活性的影响

本研究观察了家兔急性心肌梗塞（ＡＭＩ）早期血浆血小板α－颗粒膜蛋白（ＧＭＰ－１４０）、血栓素Ｂ２（ＴＸＢ２）、组织型纤溶酶酶原激活剂（Ｔ－ＰＡ）及其抑制物（ＰＡＩ－１）水平的变化及卡托利干预的ＰＡ活性显著降低；相关分析表明，血浆ＧＭＰ－１４０浓度与ＰＡＩ－１活性显著正相关。卡托普利干预后，血浆ＧＭＰ－１４０浓度、ＴＹＸＢ２浓度、Ｔ－ＰＡ浓度、ｔ－ＰＡ含量、ＰＡＩ－１活性均明显降低，而ｔ－ＰＡ活性显     

Apelin and vascular endothelial growth factor are associated with mobilization of endothelial progenitor cells after acute myocardial infarction

This study was designed to determine the levels of early endothelial progenitor cells(EPCs),apelin,vascu-lar endothelial growth factor(VEGF) and stromal cell-derived growth factor-1(SDF-1) after acute myocardial infarction(AMI),and to investigate the relationships between these cytokines and early EPCs.Early EPCs,de-fined as CD133+,KDR+,and CD34+ cells,were quantified by flow cytometry.The levels of early EPCs and those cytokines in AMI patients were significantly different from those with coronary artery disease or controls(P < 0.05).Plasma apelin levels were inversely correlated with Gensini score and early EPCs(both P < 0.01).Early EPCs,VEGF and SDF-1 showed different patterns of changes in AMI patients during the first 24 h.The trend in the change of early EPCs was proportionally correlated with that of VEGF(P < 0.05).AMI patients exhibited in-creased early EPCs with remarkably decreased apelin levels and enhanced VEGF levels.     

急性心肌梗塞病人高频心电图分析及动态观察的临床意义

本文对２８例急性心肌梗塞病人及２０例正常人做了高频心电图检查。并对１２人做了３－４周的动态观察。结果表明：急性心肌梗塞患者高频成分明显增多，有并发症者高频成分增加更明显，动态观察显示，急性心肌梗塞患者第２周高频成分减少，第３－４周高频成分又稍增加，反映了急性心肌梗塞的病情变化。     

急性心肌梗死患者心肌损伤标志物动态监测价值的比较

为探讨两组心肌损伤标志物对AMI的早期诊断和预后评估的价值,采用化学发光免疫分析法、免疫比浊法和酶学速率法对79例AMI（急性心肌梗死）组患者和40例非AMI组患者2、4、8、12、24h和2、4、7、14d的血清或血浆进行蛋白肽类标志物（Myo、cTnI、hs．CRP、BNP）和心肌酶学标志物（CK．MB、LDH、AST、α-HBDH）水平的动态测定。结果表明AMI组患者血清或血浆中两组标志物均明显高于非AMI组,具有显著性差异（P〈0．01）;AMI患者在发病2—4h后联合监测Myo、cTnI、hs—CRP和BNP阳性率明显高于CK—MB、LDH、AST和α-HBDH具有显著性差异（P〈0．01）。以上数据表明Myo、cTnI、hs—CRP和BNP联合测定对AMI作出更准确早期诊断,有较高的临床应用价值。