异丙肾上腺素对犬右心室肌细胞L型钙电流不均一性的影响

目的测定犬右心室三层心肌细胞上参与离子流平衡的内向电流L型钙电流(ICa.L)的特性,并研究其对异丙肾上腺素的反应。方法经酶解分离获得犬右心室外膜下细胞、M细胞和内膜下细胞,应用全细胞膜片钳技术,记录并比较不同部位心肌细胞的ICa.L,分析使用异丙肾上腺素前后电流-电压曲线的差异。结果ICa.L的峰值电流密度(pA/pF)在右心室外膜下细胞、M细胞和内膜下细胞分别为-4.868±1.362(n=20),-3.594±0.544(n=20)和-2.874±0.547(n=20),差异有统计学意义(F=33.493,P<0.05)。使用0.5μmol/L异丙肾上腺素后,右心室外膜下心肌细胞ICa.L的峰值电流密度由-4.832±1.127(n=11)增至-22.348±4.057(P<0.01),M细胞由-3.726±1.051(n=11)增至-17.992±4.159(P<0.01),心内膜下心肌细胞用药前后变化(-2.714±0.879,-2.987±1.012)差异无统计学意义(P>0.05)。结论ICa.L在犬右心室肌的不同细胞(外膜下心肌细胞、M细胞、内膜下心肌细胞)存在不均一性,β-肾上腺能激动剂可以减小右心室外膜下心肌细胞和M细胞动作电位复极1期末离子流的外向转移。     

利多卡因对家兔左右心室外膜心肌细胞电不均一性的影响

目的:探讨利多卡因对家兔左、右心室心外膜心肌细胞动作电位和钠电流(INa)的影响,阐明利多卡因引起左、右心室心外膜心肌细胞电不均一性机制。方法:酶解法分离家兔单个左、右心室心外膜心肌细胞,全细胞膜片钳技术记录左、右心室心外膜心肌细胞动作电位和INa在应用利多卡因前后变化。结果:在电流钳制下,对照组中的左、右心室心外膜心肌细胞上记录动作电位都具有典型的0至4期的形态,2相平台期有心外膜心肌细胞特有的穹窿样凸起;但在利多卡因组,左、右心室心外膜心肌细胞动作均明显地失去2相平台期穹窿样凸起和高度,右室心外膜心肌细胞动作电位失去2相平台期立即复极,形似三角形,左、右心室心外膜心肌细胞动作电位的幅度(APA)和复极化50%和90%(APD50和APD90)均明显减少(P<0.05),且右室心外膜心肌细胞的APA和APD50以及APD90受利多卡因影响后减小最为严重(P<0.05或0.01)。通过电压钳制方式,利多卡因使左、右心室心外膜心肌细胞的INa在各个指令电位下明显减小,而且右室心外膜心肌细胞INa减小的幅度要显著强于左室心外膜心肌细胞INa的减小幅度,当钳制电压为-20mV时,左、右心室心外膜心肌细胞的INa分别由(62.1±4.5)和(54.2±2.9)减小为(40.8±3.2)和(26.5±2.1)(P<0.05或0.01)。利多卡因还使左、右心室心外膜心肌细胞INa的I-V曲线明显上抬,尤其是使右室心外膜心肌细胞INa的I-V曲线处在其他曲线最上面,同时引起左、右心室心外膜心肌细胞的INa电流密度的最大峰值由-20mV略向右偏为-10mV。结论:利多卡因可以引起左、右心室心外膜心肌细胞电不均一性,其可能原因是利多卡因对右室心外膜心肌细胞动作电位和INa的影响程度明显强于左室相同情况。     

犬左心室肌细胞钙电流异质性

目的研究犬左心室壁外膜层、中层(M细胞)及内膜层细胞的L型钙电流大小,观察氯化镉阻断钙电流后,三层心肌单个细胞跨膜动作电位的变化。方法应用膜片钳全细胞记录技术。结果去极电压为 10mv时,I_(Ca,L)电流的峰值达最大,在心外膜、M细胞及心内膜细胞间存在显著差异,分别为-4.0±1.2、-5.3±0.4及-4.3±1.2pA/pF,(P<0.05)。在其它去极电压,三层细胞钙电流值无显著差异。氯化镉(0.2mM)使三层细胞动作电位均缩短,心内膜、M细胞及心外膜细胞APD_(90)分别由用药前的436.4±39.0ms,511.6±48.7ms,431.8±42.36ms缩短至用药后的293.4±41.7,296.7±50.3,295.2±40.9ms,APD_(90)分别缩短32.8％,42.0％,31.6％(P<0.05)。结论犬心室外膜、中层(M细胞)及内膜细胞的L型钙电流分布的差异性。     

在体犬心肌M区单相动作电位研究

目的比较在体犬M区(心肌中层)与心内膜层和心外膜层心肌的单相动作电位(MAP).方法应用Franz MAP接触电极记录技术.结果(1)心率为110次/分时体表心电图基本正常.M区和心外膜MAP,在复极早期有典型的"峰和园顶".此时心内膜层单相动作电位时程(MAPD)与M细胞相似均比心外膜层MAPD90长,分别为213±18ms、210±35ms和201±41ms(P＜0.01,n=9).(2)内膜层激动时间最短,M区的次之,外膜层的最长,它们分别为4.3±2.1ms、8.2±4.3ms和15.9±5.0ms(P＜0.01,n=9).结论在体情况下,心内膜层MAPD与M细胞相似均比心外膜层的长.     

雌激素对大鼠心肌细胞钙的调控作用研究

目的　观察雌激素对大鼠心肌细胞钙转运的调控作用 .方法　应用膜片钳全细胞记录方法观察 L型钙通道电流 (ICa.L) ,共聚焦显微镜系统分析细胞内钙浓度 ([Ca2 +]i)的变化 .结果　应用 10 μmol· L- 1和 30 μmol· L- 1的 17β- Estradiol,分别使 ICa.L抑制到正常的 (4 8.1± 4.5 ) %和 (2 9.3± 5 .2 ) % (n=5 ,P<0 .0 1) . 10μmol· L- 1 的 17β- Estradiol可升高静息的培养心肌细胞[Ca2 +]i,荧光强度 (FI)值由 5 4.2± 13.6增加到 86 .5± 15 .3(n=6 ,P<0 .0 1) ;而对具有自发收缩的心肌细胞钙瞬变幅度有明显的抑制作用 ,由给…     

藻酸双酯钠对豚鼠心室肌细胞离子电流的作用

目的:观察藻酸双酯钠(Polysaccharide sulfate,PSS)对豚鼠单个心室肌细胞离子流的影响。方法:采用Ⅰ型胶原酶分离单个豚鼠心室肌细胞的方法,利用全细胞膜片箝记录技术,在不同箝制条件下,记录并分析了PSS对L-型Ca2+电流(ICa,L)、内向整流K+电流(IK1)的影响。结果:①PSS使ICa,L的激活时间常数变大,电流幅度减小,Ⅰ-Ⅴ曲线上移。在箝制电位为+10 mV时,PSS在6-9 min内使ICa,L的激活时间常数从(0.92±0.10)ms增加到了(1.15±0.11)ms(n=5,P<0.052);ICa,L的电流幅度从(16.80±1.71)pA/pF下降至(13.86±1.67)pA/pF(n=5,P<0.01)。②PSS可使IK1的内向成分和外向成分均增加。当箝制电位在-170 mV时,PSS能使IK1内向电流幅度从(224±16.17)pA／pF增加至(257±17.36)pA／pF(n=7,P<0.01);箝制电位在-50 mV时,PSS使IK1的外向电流幅度从(8.89±0.86)pA／pF增加至(10.38±1.18)pA／pF(n=7,P<0.05)。在反转电位附近时(-70--120 mV),PSS的作用不明显。PSS能使IK1的激活时间常数减小,当箝制电位在-160 mV时,激活时间常数从加药前的(1.05±0.11)ms减小到了加药后的(0.78±0.90)ms(n=7,P<0.01);同时,IK1的电导值变大,从(2.53±0.17)nS／pF增加到了(2.82 ±0.20)nS／pF(n=7,P<0.05)。结论:PSS对L-型Ca2+电流有抑制作用,对内向整?     

丹参对缺血心肌细胞L-型钙电流的影响

目的 :观察丹参对缺血心肌细胞L 型钙电流 (ICa L)的影响。方法 :应用膜片钳全细胞记录技术。结果 :5 0 ,10 0 ,2 0 0mg/L丹参分别将缺血心肌细胞ICa L 的峰值从 (6 5 9.7± 14 8.5 ) pA降至 (5 31.9± 113.2 ) pA、(492 .4± 4 9.3) pA、(341.8± 72 .6 )pA(n =8,P <0 .0 5或P <0 .0 1)。结论 :丹参能有效地减少缺血心室肌细胞的ICa L ,这种作用可能是其抗心肌缺血以及缺血性心律失常的机制之一     

模拟缺血对左心室心肌细胞瞬间外向钾电流跨壁异质性的影响

目的研究模拟缺血对左心室心肌细胞瞬间外向钾通道电流(Ito)的跨壁异质的影响。方法采用膜片钳全细胞模式记录左心室3层心肌细胞的Ito,并观察模拟缺血对心肌Ito跨壁异质性的影响。结果左心室3层细胞的Ito电流存在异质性,表现为心外膜层(Epi)的Ito电流密度-电压关系(I-V)曲线最高,测试电压 70mV的Ito电流密度Epi明显大于中层细胞(M)和心内膜细胞(Endo),Epi、Endo和M的Ito电流密度分别为113.06±16.32(n=10),30.12±6.58(n=9)和51.43±5.68 pA/pF(n=8)。3层细胞的Ito失活无明显差异,M细胞的Ito失活后再恢复最慢。模拟缺血后,Epi的Ito I-V曲线呈时间依赖性下移,Endo呈时间依赖性上移,M细胞先上移然后下移;M细胞的Ito失活曲线左移,而Epi和Endo右移;模拟缺血3层细胞的Ito失活后再恢复无明显差异。结论左心室心肌细胞的Ito存在跨壁异质性;模拟缺血缺氧增加了兔左心室Ito的跨壁异质性。     

猪急性心肌梗死后钾通道Kv2.1、Kir2.1基因表达的变化

目的:研究猪急性心肌梗死后梗死边缘区钾通道Kv2.1、Kir2.1 mRNA表达的变化。方法:通过结扎猪左前降支中下段2 h后再灌注建立急性心肌梗死模型(MI),手术后存活猪进入MI组,同时设立相应的假手术组(SH),于24 h后取左心室梗死边缘区及假手术组相应部位,应用半定量逆转录-聚合酶链反应方法检测心外膜和心内膜心肌内向整流性钾电流亚单位(Kir2.1)、延迟整流性钾电流亚单位(Kv2.1)mRNA的表达量。结果:Kv2.1基因表达在SH组左心室心内膜和心外膜间没有差异,而Kir2.1基因表达在心内膜高于心外膜(P<0.05),MI组Kv2.1基因表达在心内膜和心外膜都显著下降(P<0.05),而且减少的程度一致,而Kir2.1基因表达只在心外膜层下降(P<0.05)。结论:局部离子通道mRNA表达的下调可能是急性心肌梗死后电生理异质性的一个决定因素,从而增加心肌梗死后电活动的不稳定性。     

模拟失重大鼠心肌细胞I_(Ca)对β-受体激动剂的反应性

目的　研究模拟失重大鼠心肌细胞钙电流 (ICa)对β-肾上腺素受体激动剂的反应性变化 .方法　用尾部悬吊大鼠模型模拟失重 (4 wk) ,胶原酶分离心肌细胞 ,用膜片钳全细胞方式记录单个心肌细胞的膜电容和 ICa等 .给予β-肾上腺素受体激动剂 (异丙肾上腺素 ) ,记录观察 ICa的反应性 .结果　对照组与悬吊组的 ICa密度无明显差别 (P>0 .0 5 ) ,ICa电流密度 -电压曲线基本一致 ;加入异丙肾上腺素后 ,两组 ICa密度均明显增大 ,但是两组的增加幅度不同 ,悬吊组的增加幅度 (84.3± 8.2 ) %明显小于对照组 (10 9.3± 7.9) % (P<0 .0 5 ) .结论　模拟失重 4wk大鼠心肌细胞的 ICa密度无明显改变 ;模拟失重后心肌细胞 ICa对 β-肾上腺素受体激动剂的反应性降低     

Anteroapical aneurysm plication improves mechanical intraventricular dyssynchrony in patients with anterior myocardial infarction

Background  Left ventricular (LV) dyssynchrony has been described to occur in patients with myocardial infarction. Dyssynchrony of left ventricular mechanical contraction produces adverse hemodynamic consequences. This study aimed to test the capacity of geometric rebuilding by aneurysm plication to restore a more synchronous contractile pattern after a mechanical, rather than electrical, intervention.

Methods  A total of sixty patients with anterior myocardial infarction, QRS duration <120 ms, electively undergoing operation between January 2008 and January 2010 were included for analysis. Real-time 3-dimensional echocardiography was performed to assess LV function, LV systolic and diastolic dyssynchrony by measuring ejection fraction (EF), peak ejection rate (PER), peak filling rate (PFR) and LV dyssynchrony. LV dyssynchrony was defined as the systolic dyssynchrony of the time to reach the minimum systolic volume for 16 LV segments, expressed in percent cardiac cycle, systolic dyssynchrony index (SDI). We compared changes of LV dyssynchrony at different interval times.

Results  LV contraction was significantly asynchronous because preoperative SDI was higher, EF, PER and PFR were lowered. Compared with function after operation, LV mechanical intraventricular resynchronization was improved with decreased SDI ((8.7±0.5) % vs. (14.3±1.6) %, P=0.01); LV function was improved with EF increasing ((43±9)% vs. (37±7)%, P=0.001), and LV systolic and diastolic dyssynchrony was improved with more rapid PFR (199.4±15.6 vs. 148.4±21.2, P=0.002) and PER (212.4±14.5 vs. 156.3±26.2, P=0.001).

Conclusions  Systolic and diastolic dyssynchrony was highly prevalent in patients with aneurysm, irrespective of QRS duration. Aneurysm plication produces a mechanical intraventricular resynchronization.

     

淫羊藿苷对兔心室肌细胞L-型钙电流的影响

目的:利用膜片钳技术研究淫羊藿苷(ICA)对兔单个心室肌细胞L-型钙电流(ICa,L)的影响。方法:采用酶解法分离兔单个心室肌细胞,应用全细胞膜片钳技术观察10,20,40μmol/L的ICA对心室肌细胞ICa,L的作用。结果:①10,20,40μmol/L的ICA使兔心室肌细胞ICa,L最大峰电流密度从(15.81±1.23)pA/pF分别降至(11.27±0.89)pA/pF,(9.48±0.85)pA/pF和(6.87±0.81)pA/pF(n=6,P<0.05),抑制率分别为28.7%,40.0%和56.5%;ICA使ICa,L的电流-电压曲线上移,但不改变其基本形状;②20μmol/L ICA可以使钙通道稳态失活曲线左移并可减慢L-型钙通道失活后的恢复过程。结论:ICA对ICa,L具有浓度依赖性阻滞作用,这可能是其抗心律失常的重要机制之一。     

2型糖尿病患者下肢皮肤微血流改变与病程的关系

目的探讨2型糖尿病患者下肢皮肤微血流改变与糖尿病病程及糖代谢控制的关系。方法应用激光多普勒血流仪对50例2型糖尿病患者(病程≤5年组24例,病程≥15年组26例)和30例对照者进行了下肢皮肤微血流的测定。下肢皮肤微血流的测定应用阻断后反应性充血(post occlusive reactive hyperemia,PORH)的方法,以左足第三趾骨背侧皮肤为测定点,应用激光多普勒血流仪(laser doppler flowmeter,LDF)记录阻断前(PORHrest)、阻断中(PORHmin)和阻断后(PORHpeak)的皮肤微血流值。微血流观察指标为PORHrest、PORHmin、PORHpeak、从开始减压到升至峰值的时间(Tp)。PORHmax=PORHpeak-PORHrest,PORHmax/Tp=(PORHpeak-PORHrest)/Tp。结果1)病程≥15年组的皮肤微血流值PORHpeak明显低于病程≤5年组,糖尿病患者2组的PORHpeak均明显低于对照组(对照组21.67±3.15,病程≤5年组16.61±6.67,病程≥15年组10.54±3.22,P均<0.01);2)病程≥15年组皮肤微血流值PORHmax明显低于病程≤5年组,糖尿病患者2组的PORHmax均明显低于对照组(对照组12.87±3.68,病程≤5年组9.76±5.89,病程≥15年组5.08±3.14,P均<0.01)。3)多元回归分析显示,糖尿病组下肢皮肤微血流PORHpeak与糖尿病病程关系最为密切(糖尿病病程的标准化回归系数为-0.575,P<0.01);下肢皮肤微血流PORHmax也与糖尿病病程关系密切(糖尿病病程的标准化回归系数为-0.533,P<0.01)。4)将50名糖尿病患者以糖化血红蛋白(HbA1c)10%为界重新分为2组,2组的年龄、性别、糖尿病病程无统计学意义(P>0.05);2组的PORHpeak、PORHmax也无统计学意义(P>0.05)。结论2型糖尿病患者下肢皮肤微血流与糖尿病病程呈负相关,短期的高血糖对下肢皮肤微血流的影响作用没有糖尿病病程的影响大。     

Ibutilide decreases defibrillation threshold by the reduction of activation pattern complexity during ventricular fibrillation in canine hearts

Background  Ibutilide has been commonly used for pharmacologic cardioversion of atrial fibrillation and flutter in clinical settings The objective of this study was to investigate the effects of ibutilide on the defibrillation threshold (DFT), restitution properties, dispersion of refractoriness and activation patterns during ventricular fibrillation (VF).

Methods  Ibutilide was administrated intravenously in six open-chest beagles. Before and after the drug administration, 20-second episodes of VF were electrically induced and recorded with a 10×10 unipolar electrode plaque sutured on the lateral epicardium of the left ventricle. DFT and VF activation patterns, including type of epicardial activation maps, VF cycle length (VF-CL), conduction velocity, wavelength (WL) and reentry incidence, were measured. Restitution properties and dispersion of refractoriness were estimated from activation recovery intervals (ARI) during pacing.

Results  Compared to baseline, ibutilide markedly decreased the DFT by 31% ((491±14) V vs. (337±59) V, P<0.01). The drug significantly reduced the maximal slope of the restitution curve (1.34±0.08 vs. 0.76±0.06, P<0.01) and its epicardial dispersion (0.36±0.09 vs. 0.21±0.06, coefficient of variation, P=0.03). The dispersion of refractoriness was enhanced at the pacing cycle length of 300 ms to 160 ms by ibutilide. The drug significantly increased the VF-CL ((96±19) ms vs. (112±20) ms, P<0.01) and the WL ((41±9) mm vs. (52±14) mm, P=0.02) during VF, and reduced the reentry incidence by 25% (0.08±0.02 vs. 0.06±0.02, P<0.01). In the epicardial activation maps, ibutilide significantly reduced the percentage of more complex activation maps during VF.

Conclusions  Intravenous ibutilide significantly decreased the DFT. It might be due to reduction of activation pattern complexity during VF.

     

Ibutilide decreases defibrillation threshold by the reduction of activation pattern complexity during ventricular fibrillation in canine hearts

Background  Ibutilide has been commonly used for pharmacologic cardioversion of atrial fibrillation and flutter in clinical settings. The objective of this study was to investigate the effects of ibutilide on the defibrillation threshold (DFT), restitution properties, dispersion of refractoriness and activation patterns during ventricular fibrillation (VF).

Methods  Ibutilide was administrated intravenously in six open-chest beagles. Before and after the drug administration, 20-second episodes of VF were electrically induced and recorded with a 10×10 unipolar electrode plaque sutured on the lateral epicardium of the left ventricle. DFT and VF activation patterns, including type of epicardial activation maps, VF cycle length (VF-CL), conduction velocity, wavelength (WL) and reentry incidence, were measured. Restitution properties and dispersion of refractoriness were estimated from activation recovery intervals (ARI) during pacing.

Results  Compared to baseline, ibutilide markedly decreased the DFT by 31% ((491±14) V vs. (337±59) V, P <0.01). The drug significantly reduced the maximal slope of the restitution curve (1.34±0.08 vs. 0.76±0.06, P <0.01) and its epicardial dispersion (0.36±0.09 vs. 0.21±0.06, coefficient of variation, P=0.03). The dispersion of refractoriness was enhanced at the pacing cycle length of 300 ms to 160 ms by ibutilide. The drug significantly increased the VF-CL ((96±19) ms vs. (112±20) ms, P <0.01) and the WL ((41±9) mm vs. (52±14) mm, P=0.02) during VF, and reduced the reentry incidence by 25% (0.08±0.02 vs. 0.06±0.02, P <0.01). In the epicardial activation maps, ibutilide significantly reduced the percentage of more complex activation maps during VF.

Conclusions  Intravenous ibutilide significantly decreased the DFT. It might be due to reduction of activation pattern complexity during VF.

     

Detection of carboxyhemoglobin in patients with hepatic encephalopathy due to hepatitis B virus-related cirrhosis

Background  The heme oxygenase/carbon monoxide (HO/CO) system plays an important role in the development of hepatic fibrosis. The level of the HO/CO can be directly obtained by determining the carboxyhemoglobin (COHb) level. The aims of this study were to reveal the significance of COHb in patients with hepatitis B virus-related cirrhosis (HBC) complicated by hepatic encephalopathy (HE), and to further investigate the influence of the HO/CO pathway on the end-stage cirrhosis, hoping to find a reliable indicator to evaluate the course of HBC.

Methods  According to the diagnostic criteria, 63 HBC inpatients with HE were enrolled in group H. Patients regaining awareness with current therapies were categorized into group P-H. Comparisons were made with a control group (group N) consisting of 20 health volunteers. The levels of COHb, partial pressure of oxygen (PaO₂) and oxygen saturation (SaO₂) were determined by arterial blood gas analysis method. The incidences of hepatorenal syndrome (HRS), upper gastrointestinal bleeding, esophagogastric varices and spontaneous bacterial peritonitis (SBP) in group H were recorded. COHb levels in different groups were compared, and the correlations of COHb levels with HE grades (I, II, III, and IV), PaO₂, SaO₂ and hypoxemia were analyzed.

Results  The COHb level in group P-H ((1.672±0.761)%) was significantly higher than that in group N ((0.983±0.231)%) (P <0.01), and the level in group H ((2.102±1.021)%) was significantly higher than groups P-H and N (P <0.01). A positive correlation was observed between the COHb concentration and the grade of HE (r_s=0.357, P=0.004). There were no significant differences of COHb levels between HE patients with and without complications such as esophagogastric varices ((2.302±1.072)% vs. (1.802±1.041)%, P >0.05) or the occurrence of SBP ((2.960±0.561)% vs. (2.030±1.021)%, P >0.05). Compared with HE patients with HRS, the level of COHb was significantly higher in HE patients without HRS ((2.502±1.073)% vs. (1.981±1.020)%, P=0.029). The COHb level had a negative correlation with PaO₂ (r=−0.335, P=0.007) while no statistically significant relationship was found with SaO₂ (r=−0.071, P >0.05). However, when the above two parameters met the diagnostic criteria of hypoxemia, the COHb concentration increased ((2.621±0.880)% vs. (1.910±0.931)%, P=0.011).

Conclusions  COHb is a potential candidate to estimate the severity and therapeutic effect of HE. The levels of COHb may be tissue-specific in cirrhotic patients with different complications.

     

机械通气对急性肺损伤兔肺水肿影响的实验研究

目的研究不同潮气量联合不同水平呼气末正压(PEEP)机械通气对急性肺损伤(ALI)兔肺水肿的影响。方法用数字表法将36只新西兰兔随机分为正常对照(NC)组、ALI组、常规潮气量(15mL/kg)低PEEP(5cmH2O)(CVLP)组、常规潮气量高PEEP(10cmH2O)(CVHP)组、小潮气量(8mL/kg)低PEEP(LVLP)组和小潮气量高PEEP组(LVHP组)。以内毒素静脉注射建立ALI动物模型,经机械通气的4组动物分别给予不同潮气量联合不同水平PEEP机械通气4h。实验结束后取肺组织测定湿质量/干质量比值评价肺水肿严重程度。结果NC组、ALI组、CVLP组、CVHP组、LVLP组和LVHP组的肺湿质量/干质量比值分别为4.81±0.19、5.84±0.20、5.47±0.28、5.25±0.12、5.24±0.12和5.12±0.10,NC组低于其他各组,差异有统计学意义(P<0.05);ALI组高于各机械通气组,差异有统计学意义(P<0.05);LVHP组低于CVLP组,差异亦有统计学意义(P<0.05)。结论机械通气能够减轻ALI肺水肿,小潮气量联合高PEEP机械通气减轻ALI肺水肿的作用更加显著。     

Epicardial radiofrequency ablation for left ventricular aneurysm related ventricular arrhythmias during off-pump coronary artery bypass surgery

Background  Left ventricular aneurysm (LVA) is one of the serious complications after acute myocardial infarction. We attempted to evaluate the preliminary efficacy of LVA repair combined with epicardial radiofrequency ablation for ventricular arrhythmia during off-pump coronary artery bypass grafting (OPCAB).

Methods  From June 2009 to April 2011, 31 patients with LVA had angina symptoms and ventricular arrhythmia. In all patients, circular and cross-shaped radiofrequency epicardial ablations were performed using unipolar ablation pen along the border between the aneurysm wall and normal cardiac tissue and in the central zone of the aneurysms, followed by a linear placation of ventricular aneurysms on beating heart.

Results  All the patients showed complete recovery. The average number of grafted vessels was 2.7±1.3. Intraoperative examinations revealed that the ventricular arrhythmia was effectively controlled by radiofrequency ablation. All cases had been followed up for one year. Holter monitoring revealed a significant reduction in ventricular arrhythmias (P <0.05). Echocardiography showed significant increase in left ventricular ejection fraction (P <0.05) and decrease in left ventricular end-diastolic diameter (P <0.05).

Conclusions  For patients with ventricular aneurysm and preoperative malignant arrhythmia, aneurysm repair plus epicardial radiofrequency ablation in OPCAB was found to be an effective and feasible therapeutic technique. However, medium- to long-term therapeutic efficacy of this method remains to be determined by future studies and observations.

     

己酮可可碱对实验性阻塞性肺气肿大鼠凝血纤溶系统的影响

目的观察实验性阻塞性肺气肿大鼠的凝血纤溶系统失衡状态及评价己酮可可碱(PTX)对实验性阻塞性肺气肿大鼠的防治效果,并探讨其机制。方法36只Wistar大鼠分为3组,正常对照组、模型组和治疗组(每组12只)。模型组、治疗组大鼠第1、14、28天经尾静脉注射内毒素3mg/kg,第2~45天(第14、28天除外)每日被动吸烟2次,每次12支,持续30min,两次吸烟之间间隔4h,大鼠模型制备过程共45d。PTX治疗组每天熏烟前30min腹腔内注射PTX15mg/kg,连续30d。实验结束后,观察各组大鼠的肺功能情况,用酶联免疫吸附法(ELISA)测定血清中肿瘤坏死因子α(TNF-α)、白细胞介素10(IL-10)、组织型纤溶酶原激活剂(tPA)、纤溶酶原激活物抑制剂-1(PAI-1)、血浆组织因子途径抑制物抗原(TFPI:Ag)的含量,发色底物法测定血浆抗凝血酶-Ⅲ(AT-Ⅲ)活性,并进行HE染色观察肺脏病理改变。结果模型组大鼠肺功能指标第0.2秒用力呼出容积占用力肺活量百分比(FEV0.2/FVC)与正常对照组(88.52±2.09)比较,差异有统计学意义(P<0.01,P<0.05);模型组大鼠AT-Ⅲ和TFPI与正常对照组比较,差异有统计学意义(P均<0.01);模型组大鼠tPA和PAI-1与正常对照组比较,差异有统计学意义(P均<0.05)。经直线相关分析发现,模型组大鼠AT-Ⅲ与TNF-α负相关(r=-0.87,P<0.01);PTX组FEV0.2/FVC、TNF-α和AT-Ⅲ与模型组比较,差异有统计学意义(P均<0.01)。组织学观察显示模型组大鼠支气管管壁及周围大量的炎性细胞浸润;肺泡结构紊乱,肺泡腔扩大。PTX组炎性细胞浸润以及肺泡腔扩大情况较模型组减轻。结论采用熏香烟加尾静脉注射内毒素的方法,可成功复制大鼠阻塞性肺气肿模型。模型组大鼠肺血管内皮细胞受损,体内的凝血纤溶系统存在失衡状态,AT-Ⅲ、TFPI、tPA和PAI-1可能参与这一过程。PTX能阻止白细胞脱颗粒、抑制气道炎症,同时增强抗凝血酶-Ⅲ的活性、改善高凝状态,对大鼠阻塞性肺气肿的形成有一定的预防作用。