二维斑点追踪技术评价低温兔左室纵向功能

目的:探讨应用二维斑点追踪技术评价低温条件下兔左心室纵向功能的价值。方法:30只新西兰兔随机分成对照组(n=10),低温组A(n=10),低温组B(n=10)。先行常规心脏数据测量,然后采用组织多普勒(TDI),之后应用斑点追踪成像(STI)中的获取基底段、中间段、心尖段及整体水平SL、SrLs.SrL E,SrL A及分层应变技术获取3个长轴切面心内膜下、中层和心外膜下心肌收缩期纵向峰值应变(SL)。结果:①与对照组相比,A组心内膜下心肌LS值的减低,差异有统计学意义(P<0.05),B组3层心肌SL值的减低明显,差异有统计学意义(P<0.01)②与对照组相比,A组大部分纵向应变及应变率减低(P<0.05);B组基底段、中间段、心尖段及整体水平SL,SrL S、SrLE、SrLA均减低(P<0.01)结论:随低温时间延长,左室壁3层心肌SL值受累程度不同,心内膜应变较心外膜更加敏感,二维班点追踪技术比LVEF及TDI更早发现左室功能减低。     

Perioperative intra-aortic balloon counterpulsation in a patient with myocardium at risk undergoing urgent noncardiac surgery

We are presenting the case of a 76-year-old female scheduled for major abdominal surgery. Her past medical history was remarkable for a three-vessel coronary artery disease, with a severely impaired left ventricular function. She had already undergone complex coronary artery bypass surgery. Currently, she presented with the rare constellation of a hemodynamic relevant and interventionally intractable stenosis of the left subclavian artery proximal to a crucial coronary bypass from left internal mammary artery to the left anterior descending. To protect this patient from perioperative myocardial infarction, an intra-aortic balloon pump was successfully used.     

长效硝酸酯对心力衰竭大鼠心脏血管紧张素Ⅱ受体表达水平的影响

目的:探讨长效硝酸酯(异乐定)对心肌梗死后慢性心力衰竭(CHF)大鼠心功能、血浆肾素活性(plasma renin activity,PRA)和血管紧张素II(Angiotensin II,Ang II)水平以及非梗死区左心室组织血管紧张素II受体(Angiotensin II receptor,ATR)各亚型表达水平的影响。方法:选用雄性Wistar大鼠,随机分为正常对照组(N组)、假手术组(SH组),结扎左冠状动脉前降支制作心肌梗死后心力衰竭模型,分为心力衰竭模型组(HF组)、硝酸酯小剂量组(LN组)、硝酸酯大剂量组(HN组)、阳性药物对照组(奥美沙坦酯,OL组)及硝酸酯大剂量联合阳性药物组(HN+OL组),灌胃法给药6周。超声心动图检测用药前后心功能,放射免疫法检测血浆PRA、Ang II水平,RT-PCR和Western blot检测各组心肌AT1R及AT2R的表达水平。结果:1用药后,与HF组相比,HN组、OL组和HN+OL组左心室射血分数(LVEF)显著升高(P<0.05);与OL组相比,HN+OL组LVEF显著升高(P<0.05)。2与SH组相比,HF组PRA、Ang II水平显著升高(P<0.01),AT2R表达水平明显上调(P<0.05),AT1R表达水平明显下调(P<0.05);与HF组相比,HN、OL和HN+OL组PRA、Ang II水平均显著下降(P<0.05、P<0.01),AT2R表达明显下调(P<0.05),AT1R表达明显上调(P<0.05);与OL组相比,HN+OL组AT1R显著上调,AT2R显著下调(P<0.05)。结论:应用长效硝酸酯能降低CHF循环中PRA、Ang II水平,同时使CHF心脏AT1R、AT2R的表达水平反向调节趋于正常,并提高LVEF,显著改善了心功能。大剂量硝酸酯的疗效明显优于小剂量,并可协同奥美沙坦改善心功能。     

Regional variation in the measured apparent ultrasonic backscatter of mid-gestational fetal pig hearts

The goal of this study was to characterize and compare regional backscatter properties of fetal hearts through measurements of the apparent integrated backscatter. Sixteen excised, formalin-fixed fetal pig hearts, representing an estimated 53 to 63 days of gestation, were investigated. Spatially localized measurements of integrated backscatter from these specimens were acquired using a 50 MHz single-element transducer. The apparent integrated backscatter measurements demonstrate different patterns of backscatter from the myocardium of the right ventricle compared with that of the left ventricle. These backscatter measurements appear to be consistent with the anisotropy of the fiber orientation observed in histologic assessment of the same specimens. For each of the 16 hearts, the apparent integrated backscatter from the right ventricular myocardium was larger than that from the left ventricular myocardium, exhibiting mean apparent backscatter values of –35.9 ± 2.0 dB and –40.1 ± 1.9 dB (mean ± standard deviation; n = 16; p < 0.001), respectively. This study suggests that the intrinsic ultrasonic properties of the left and right ventricular myocardium are distinct in fetal pig hearts at mid-gestation. (E-mail: mrh@wuphys.wustl.edu)     

心肌肌钙蛋白T和超敏C反应蛋白在不稳定型心绞痛危险分层中的作用

目的研究不稳定型心绞痛(UAP)患者血清心肌肌钙蛋白T(cTnT)和超敏C反应蛋白(hs-CRP)水平变化与冠状动脉造影结果的关系,以评价cTnT和hs-CRP在UAP危险分层中的作用。方法序贯征集来住院的确诊为BraunwaldⅢB级UAP患者120例。在患者入院时(0h)及第一个24h内(3、6、12、18h)分别采集血样,测定cTnT、hs-CRP和肌酸激酶同工酶-MB(CK-MB)血浓度。根据cTnT水平不同,将患者分为cTnT阴性组(80例)和cTnT阳性组(40例)。所有患者出院前都进行冠状动脉造影。结果cTnT阴性组与cTnT阳性组比较,hs-CRP水平较低(2.3mg/L与12.6mg/L,P=0.001),3支血管患病率较低(26%与43%,P=0.001),左冠状动脉主干患病率较低(5%与15%,P=0.04),冠脉栓塞患病率较低(4%与20%,P=0.006),重度狭窄的血管较少(65%与95%,P=0.001),一年内心血管事件发病率较低(2.5%与25%,P<0.001)。结论cTnT和hs-CRP可对UAP进行危险分层,对UAP的诊断、疗效监测及预后判断有重要作用。     

Erythropoietin facilitates the return of spontaneous circulation and survival in victims of out-of-hospital cardiac arrest

Background

Erythropoietin activates potent protective mechanisms in non-hematopoietic tissues including the myocardium. In a rat model of ventricular fibrillation, erythropoietin preserved myocardial compliance enabling hemodynamically more effective CPR.

Objective

To investigate whether intravenous erythropoietin given within 2 min of physician-led CPR improves outcome from out-of-hospital cardiac arrest.

Methods

Erythropoietin (90,000 IU of beta-epoetin, n = 24) was compared prospectively with 0.9% NaCl (concurrent controls = 30) and retrospectively with a preceding group treated with similar protocol (matched controls = 48).

Results

Compared with concurrent controls, the erythropoietin group had higher rates of ICU admission (92% vs 50%, p = 0.004), return of spontaneous circulation (ROSC) (92% vs 53%, p = 0.006), 24-h survival (83% vs 47%, p = 0.008), and hospital survival (54% vs 20%, p = 0.011). However, after adjusting for pretreatment covariates only ICU admission and ROSC remained statistically significant. Compared with matched controls, the erythropoietin group had higher rates of ICU admission (92% vs 65%, p = 0.024) and 24-h survival (83% vs 52%, p = 0.014) with statistically insignificant higher ROSC (92% vs 71%, p = 0.060) and hospital survival (54% vs 31%, p = 0.063). However, after adjusting for pretreatment covariates all four outcomes were statistically significant. End-tidal PCO₂ (an estimate of blood flow during chest compression) was higher in the erythropoietin group.

Conclusions

Erythropoietin given during CPR facilitates ROSC, ICU admission, 24-h survival, and hospital survival. This effect was consistent with myocardial protection leading to hemodynamically more effective CPR (Trial registration: http://isrctn.org. Identifier: ISRCTN67856342).     

心肌造影超声心动图诊断犬急性高血糖心肌微血管功能损害的实验研究

目的　探讨犬急性高血糖对冠状动脉和心肌微血管血流量及血流储备的影响。方法　 16条杂种犬 ,静脉注射双嘧达莫前后 ,应用血流仪和心肌造影超声心动图 (MCE)测量基础状态和高血糖状态时冠状动脉前降支和心肌微血管的血流量。结果　应用双嘧达莫前 ,基础状态和高血糖状态的前降支和心肌微血管的血流量 [( 13 .94± 2 .92 )ml/min对 ( 15 .0 5± 8.61)ml/min和 ( 4 5 .49± 14 .2 8)ml/min对 ( 4 8.62± 2 9.5 9)ml/min ,P >0 .0 5 ]以及微血管密度 ( 5 7.0 5± 7.87对 68.65± 10 .0 0 ,P >0 .0 5 )均差异无显著性意义 ;应用双嘧达莫后 ,前降支血流量和血流储备无明显变化 ,而心肌微血管的血流量 [( 91.71± 42 .67)ml/min对 ( 4 1.16± 2 3 .15 )ml/min ,P <0 .0 1]、血流速度 [( 1.11± 0 .61)ml/min对 ( 0 .67± 0 .2 7)ml/min ,P <0 .0 5 )、血管密度 ( 86.78± 2 1.84对 65 .18± 2 8.5 8,P <0 .0 1)和血流储备 ( 2 .15± 1.3 0对 0 .84±0 .44 ,P <0 .0 1)明显下降。结论　急性高血糖减少双嘧达莫负荷后的心肌微血管的血流量、血流储备和血管密度。     

基于反转恢复实时快速小角度激发成像的心肌T1值量化方法

目的验证反转恢复实时快速小角度激发(IR-rttfl)成像的心肌T1量化方法。方法对仿体、健康志愿者和心肌坏死患者分别进行成像,在3.0T磁场中使用IR-rttfl的扫描方法量化心肌T1值,与MOLLI方法的结果进行对比,并将T1量化的结果用于分析心肌的异常区域。结果 IR-rttfl方法将扫描时间缩短到6s以内,T1量化结果比MOLLI方法更准确,并且能够有效区分患者心肌的异常区域。结论这种方法能够有效抑制心律不齐造成的影响,提高心肌T1量化结果的准确性,对心肌坏死的诊断具有重要意义。