实时三维超声心动图评价犬多巴酚丁胺负荷试验中左心室容积的变化

目的应用实时三维超声心动图(RT-3DE)定量评价犬多巴酚丁胺(Dob)负荷试验(DSE)中左心室容积的变化。方法健康杂种犬32条,随机分为3组:心肌顿抑组8条(冠状动脉结扎15min,再灌注30min),心肌梗死组16条(冠状动脉结扎180min,再灌注30min),正常对照组8条。按照心脏负荷5min阶段程序行DSE。应用RT-3DE获取犬静息状态及输注Dob5、10、20、30、40μg.kg-1.min-1及终止后5min的RT-3DE容积数据库,根据心尖长轴观8平面法勾画左室舒张末期容积(LVEDV)及收缩末期容积(LVESV)。比较三组实验犬DSE过程中LVEDV及LVESV的变化。结果正常对照组:随Dob剂量的逐级增加,平均LVEDV和LVESV明显减小;心肌顿抑组:平均LVEDV和LVESV在Dob<20μg.kg-1.min-1时呈减小趋势,在Dob≥20μg.kg-1.min-1时呈增大趋势;心肌梗死组:平均LVEDV和LVESV在Dob<20μg.kg-1.min-1时也呈减小趋势,但在Dob≥20μg.kg-1.min-1时则明显增大。三组实验犬LVEDV及LVESV呈不同的变化趋势。结论应用RT-3DE定量分析DSE过程中左室容积的变化,可以区分心肌顿抑和心肌梗死。RT-3DE有望为临床定量评价心肌顿抑和心肌梗死提供一项有效手段。     

实时三维超声心动图定量评价心肌梗死犬多巴酚丁胺负荷实验中左室容积的变化

目的　应用实时三维超声心动图 (RT- 3DE)定量评价心肌梗死犬多巴酚丁胺负荷实验 (DSE)过程中左室容积的变化。方法　建立犬急性心肌梗死模型。分别对 12条犬在冠脉结扎前及冠脉结扎 180 min-再灌注 30 min后行 DSE。应用 RT- 3DE获取犬静息 (rest)及输注多巴酚丁胺 (Dob) 5、 10、 2 0、 30、 4 0 μg/ (kg·min)及终止后 5 min时 (recovry)的 RT- 3DE容积数据库 ,根据心尖长轴 8平面法勾画左室舒张末期容积 (L VEDV)及收缩末期容积 (L VESV) ;计算其从静息至峰值负荷时的容积变化分数 ΔVLVEDV%及 ΔVL VESV%。结果　 (1)冠脉结扎前 :随 Dob剂量的逐级增加 ,平均 L VEDV和 L VESV明显减小 ;冠脉结扎 180 min-再灌注 30 min后 :平均 L VEDV和 L VESV在 Dob<2 0 μg/ (kg· min)时也呈减小趋势 ,但在 Dob≥ 2 0 μg/ (kg·min)时则明显增大。两者呈不同的变化趋势 ;(2 )冠脉结扎前及冠脉结扎 180 min-再灌注 30 min后平均ΔVL VEDV%分别为 14 .75 %及 7.95 % (n=12 ,P=0 .0 0 1) ;平均 ΔVLVESV%分别为 39.86 %及 2 0 .75 % (n=12 ,P<0 .0 0 1)。后者明显小于前者。结论　通过应用 RT- 3DE分析 DSE过程中左室容积的变化 ,可以区分正常犬与心肌梗死犬。     

实时三维超声心动图评价多巴酚丁胺对心肌顿抑和梗死犬左心室局部径向距离的影响

目的应用实时三维超声心动图(RT-3DE)定量评价多巴酚丁胺对心肌顿抑犬和心肌梗死犬左心室局部径向距离的作用。方法建立犬的心肌顿抑[冠状动脉(冠脉)结扎15 min,再灌注30 min]和急性心肌梗死(冠脉结扎180 min,再灌注30 min)模型。于冠脉结扎前和冠脉结扎-再灌注后,用微量输液泵经股静脉输注多巴酚丁胺5及10μg.kg-1.min-1,每一剂量持续5 min。应用RT-3DE获取实验犬静息状态及输注多巴酚丁胺10μg.kg-1.min-1后RT-3DE全容积数据库。脱机后,根据心尖长轴观8平面法重建收缩末期左室立体几何形状;以二尖瓣环中点至左室心尖部心内膜的连线为中心轴,将左室等分成与中心轴垂直的1.0 cm厚互相平行的短轴平面,从中选取室壁运动异常(WMA)面积最大者作为研究平面;在此平面上,以轴心与左室后壁连线所在位置为0°,逆时针每隔20°测量心内膜至轴心的距离(即径向距离R,共可测得18个值)。将冠脉结扎-再灌注后两组实验犬输注多巴酚丁胺前、后的平均R值与冠脉结扎前(设为基础状态)输注多巴酚丁胺前、后的相应R值进行比较。结果静息状态下,心肌顿抑组和心肌梗死组中所选研究平面结扎冠脉供血区平均R值均明显增大(均P<0.001)。输注多巴酚丁胺后,心肌顿抑组中上述异常增大的平均R值均明显减小(均P<0.001),但未恢复至基础状态水平(均P<0.05);心肌梗死组中上述异常增大的平均R值均无明显改变(均P>0.05)。结论通过应用RT-3DE分析输注多巴酚丁胺前、后左室局部径向距离的变化,可以识别心肌顿抑和心肌梗死。RT-3DE有望为临床定量评价左室局部几何形状提供一项有效手段。     

应变率结合多巴酚丁胺负荷试验检测冠心病

目的探讨应变率结合多巴酚丁胺负荷超声心动图(DSE)诊断冠心病的临床价值。方法对经冠脉造影证实的18例冠心病患者和10例正常人进行大剂量DSE。测量各节段收缩期最大应变率(SRSYS)和收缩期达峰时间(TP)。结果40μg/(kg·min)时,缺血节段较之正常组SRSYS显著降低、TP显著延长。与静息状态相比,40μg/(kg·min)时正常组SRSYS极显著增加、TP显著缩短,缺血节段SRSYS显著增加、TP无显著变化。结论DSE与应变率结合定量评价局部心肌运动为临床诊断冠心病提供了有价值的信息。     

实时三维超声心动图定量评价多巴酚丁胺对心肌顿抑犬和心肌梗死犬左室局部几何形状的作用

目的应用实时三维超声心动图(RT-3DE)定量评价多巴酚丁胺对心肌顿抑犬和心肌梗死犬左室局部几何形状的作用。方法健康杂种犬32条,随机分为3组:心肌顿抑组(8条),心肌梗死组(16条),正常对照组(8条)。应用RT-3DE获取3组试验犬静息状态(Rest)及输注多巴酚丁胺(Dobutamine,Dob)10μg/(kg·min)的RT-3DE全容积数据库。脱机后进行后处理分析:采用心尖长轴观8平面法重建收缩末期左室立体几何形状。将二尖瓣环中点至左室心尖部心内膜最远点的连线定义为左室中心轴;将左室由心尖部至二尖瓣环等分成与中心轴垂直的10mm厚互相平行的短轴切面,从中选取室壁运动异常面积最大者作为研究平面。手动勾画所选研究平面收缩末期心内膜边界,测量其面积(A)和周长(C),计算Gibson圆形指数(CSI)(公式:CSI=4πA/C2),以此作为定量评价左室局部几何形状的指标。比较输注Dob前、后3组实验犬所选研究平面平均CSI的变化。结果(1)正常对照组静息状态下,所选研究平面平均CSI为0.971,接近于1;输注Dob后,平均CSI无明显变化(CSI=0.980,P>0.05);(2)心肌顿抑组静息状态下,所选研究平面平均CSI较正常对照组明显减小(CSI=0.950,P<0.05);输注Dob后,平均CSI明显增大(CSI=0.965,P<0.01),较正常对照组无明显差异(P>0.05);(3)心肌梗死组静息状态下,所选研究平面平均CSI较正常对照组也明显减小(CSI=0.931,P<0.001);输注Dob后,上述平均CSI明显增大(CSI=0.940,P<0.05),较正常对照组有明显差异(P<0.05)。结论通过应用RT-3DE分析输注Dob前、后左室局部几何形状的变化,可以区分心肌顿抑和心肌梗死。RT-3DE有望为临床定量评价左室局部几何形状提供一项有效手段。     

应变率成像结合大剂量多巴酚丁胺负荷试验评价早期冠心病左室心肌舒张功能

目的 探讨应变率成像(SRI)结合大剂量多巴酚丁胺负荷超声心动图(DSE)评价早期冠心病左室心肌舒张功能变化.方法 对28例可疑冠心病患者进行大剂量DSE,测量舒张早期峰值应变率(SRe)和舒张晚期峰值应变率(SRa),并进行冠心病组和正常对照组的比较.结果 冠心病组缺血节段SRe在Dob剂量20μg/(kg·min)时达到最大,与静息状态比较差异有统计学意义;在Dob剂量30和40μg/(kg·min)时降低,与正常对照组、非缺血节段同一负荷状态比较差异有统计学意义.以Dob剂量40μg/(kg·min)时SRe≤1.70为截断值,预测缺血心肌舒张功能异常的敏感性和特异性分别为88.9%和83.3%.结论 SRe是反映心肌局部舒张功能变化敏感而特异的指标.     

不同多巴酚丁胺超声负荷方法对存活心肌的检出价值

目的:探讨小剂量多巴酚丁胺负荷超声心动图(LDDSE)与标准剂量多巴酚丁胺负荷超声心动图(DSE)对存活心肌的检出价值。方法:对14例正常人(CON)和20例冠心病(CAD)患者采用标准的DSE方案(0～40μg?kg·min),分别记录静息状态及不同剂量负荷时左室室壁运动情况,并计算静息状态、小剂量(10μg?kg·min)及峰值剂量(40μg?kg·min)负荷时CAD组室壁运动积分(WMSI)的变化。结果:共观察544个心肌节段,CAD组在LDDSE中运动改善者81个,其中75个节段在DSE中发生双相反应,被视为存活心肌。CAD组WMSI静息(b)、小剂量(l)、大剂量(p)时分别为1.36±0.21(P<0.001),1.17±0.16(P<0.001),1.48±0.20(P<0.05)。结论:DSE对CAD病人存活心肌的无创性诊断具有应用价值,LDDSE检测CAD患者存活心肌具有较高的敏感性,但特异性低于DSE双相反应方法。     

多巴酚丁胺负荷试验时应变率检测冠心病的价值

目的探讨应变率技术结合多巴酚丁胺负荷试验(DSE)检测冠心病的价值。方法对28例可疑冠心病患者进行大剂量DSE,测量收缩期最大应变率(SRs)、舒张早期峰值应变率(SRe)和舒张晚期峰值应变率(SRa)。结果冠心病组SRs随着Dob量的增加而逐渐增大;而SRe 20、30、40μg.kg-1.min-1时较静息显著减低。SRs 30、40μg.kg-1.min-1时低于同一注药速度正常组;SRe在各阶段均低于正常组。结论DSE与应变率结合定量评价局部心肌运动变化,为临床诊断冠心病提供了有价值的信息。     

缺血-再灌注不同时间点给予尼可地尔对犬心肌梗死范围的影响

目的　证实尼可地尔是通过激活心肌细胞 KATP通道而起到使梗死心肌范围明显缩小的作用 ;进一步了解在冠状动脉 (冠脉 )闭塞心肌缺血前后和再灌注时给予尼可地尔产生的心肌保护作用是否相同 ,为临床上应用 KATP通道开放剂防治急性心肌缺血性疾病提供依据。方法　 35条犬随机分为 5组 ,每组 7只。缺血再灌注组 (IR组 ) :冠脉左前降支 (L AD)闭塞 90 min,再灌注 12 0 min。缺血前给予尼可地尔组 (PNIC组 ) :L AD闭塞前 10 min经静脉给予尼可地尔 10 0μg/ kg,随后给予 10μg· kg- 1 · min- 1 持续静脉滴注至再灌注结束。缺血后 15 m in给予尼可地尔组 (INIC组 ) :L AD闭塞后 15 m in经静脉给尼可地尔 10 0μg/ kg,随后给予10 μg· kg- 1· min- 1持续至再灌注结束。再灌注开始时给予尼可地尔组 (RNIC组 ) :L AD闭塞 90 min,再灌注开始时立即静脉给尼可地尔 10 0 μg/ kg,随后给予 10 μg· kg- 1· m in- 1持续至再灌注结束。KATP通道阻滞剂组(GL IB+INIC组 ) :在 L AD闭塞前 10 min经静脉给予优降糖 0 .3m g/ kg 10 min,随后步骤同 INIC组。各组均在冠脉闭塞前、冠脉闭塞后 1h、再灌注 2 h测定血流动力学指标 ;再灌注 2 h后用图像分析仪测量氯化三苯四唑 (TTC)染色的梗死心肌范围 (IA)和危险心肌范围 (     

先天性心脏病伴肺动脉高压患儿术中应用前列腺素E1的临床观察

目的:了解术中应用不同剂量前列腺素E1(PGE1)对先天性心脏病伴肺动脉高压患儿的血流动力学影响.方法:30例先天性心脏病患儿随机分为3组,即对照组、应用PGE120ng/(kg·min)组(试验A组)及应用PGE1100 ng/(kg·min)组(试验B组),连续监测患儿的心率(HR)、体循环动脉收缩压(SDP)变化,分别在切皮前及停体外循环30 min经食管超声心动图测定左心室射血分数(EF)、肺动脉平均压(MPAP)及肺动脉和主动脉血流量比值(Qp/Qs).结果:术中应用不同剂量PGE1患儿的HR、EF及QP/Q.差异无显著性,但患儿的MPAP和SDP差异有显著性,PGE120 ng/(kg·min)时,MPAP已显著下降,当剂量加大至100 ng/(kg·min)时,MPAP进一步下降,同时SDP明显下降.结论:术中应用PGE1对先天性心脏病伴肺动脉高压患儿的肺血管有较好的选择性,20 ng/(kg·min)即有显著疗效,但不宜超过100ng/(kg·min).     

Emergency echocardiography

Emergency echocardiography refers to the use of cardiac ultrasound to address critical and time-sensitive clinical questions during the initial evaluation and treatment of the critically ill patient presenting to the emergency department. The information obtained can be pivotal to a physician's clinical decision making and can guide further diagnostic or therapeutic interventions. This article provides an evidence-based discussion of the common uses of emergency transthoracic echocardiography, as well as its benefits and limitations in the current practice of emergency medicine.     

Stress echocardiography

Stress echocardiography is the combination of 2D echocardiography with a physical, pharmacological or electrical stress. The diagnostic end point for the detection of myocardial ischemia is the induction of a transient worsening in regional function during stress. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging but at a substantially lower cost, without environmental impact and with no biohazards for the patient and the physician. In spite of its dependence upon operator’s training, it is the best possible choice to achieve the still elusive target of sustainable cardiac imaging in the field of noninvasive diagnosis of coronary artery disease.     

Stress echocardiography

Stress echocardiography is the combination of 2D echocardiography with a physical, pharmacological or electrical stress. The diagnostic end point for the detection of myocardial ischemia is the induction of a transient worsening in regional function during stress. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging but at a substantially lower cost, without environmental impact and with no biohazards for the patient and the physician. In spite of its dependence upon operator's training, it is the best possible choice to achieve the still elusive target of sustainable cardiac imaging in the field of noninvasive diagnosis of coronary artery disease.     

Contrast echocardiography

Contrast echocardiography is the technique of injecting an echo-producing, biologically compatible solution into the bloodstream and using M-mode and/or two-dimensional echocardiography to observe intracardiac bloodflow patterns revealed by the resulting cloud of echoes. This information was previously available only from angiocardiography. Contrast echocardiography has become a well-established adjunct to M-mode and two-dimensional echocardiographic examination and is valuable in the identification and validation of normal and abnormal cardiac structures, for the demonstration (and exclusion) of intracardiac as well as extracardiac shunts, and in the diagnosis of valvular regurgitation. In addition many clinical applications are being developed. Future research directions include development of videodensitometric techniques for contrast quantitation, finding contrast agents capable of passing the lung capillary bed and measurement of right heart pressures using microbubble resonance techniques.     

Transesophageal echocardiography

Transesophageal echocardiography has provided a new acoustic window to the heart, the great vessels, and the mediastinum. It provides anatomical, functional hemodynamic, and blood flow information. High-quality visualization of left atrial appendage, thoracic aorta, atrial septum, and mitral valvular apparatus can be obtained readily. We discuss historical and technical aspects of transesophageal echocardiography, anatomical views, and major clinical indications for this procedure. These indications include intracardiac masses, thoracic aortic dissection, endocarditis, prosthetic and native cardiac valve function assessment, as well as its value in the detection of intracardiac source of systemic emboli. Furthermore, the role of transesophageal echocardiography in the assessment of coronary artery and congenital heart disease and as an intraoperative diagnostic and monitoring technique is discussed.     

Transesophageal echocardiography

Two-dimensional transesophageal echocardiography generally has superior sensitivity and image quality compared with precordial echocardiography. Its unique anatomic perspective posterior to the heart often provides important clinical information not obtainable by other imaging approaches and technologies. It is particularly useful in the diagnosis of mitral valve disease, left atrial masses, endocarditis and its sequelae, and aortic dissections. It is also useful for examination of the left main coronary artery, left ventricular outflow tract, atrial and ventricular septa, and congenital defects. In addition to its application as a diagnostic tool in conscious patients, it can be employed intraoperatively to evaluate and guide surgical intervention. Detection of ventricular wall motion abnormalities by transesophageal echocardiography has been shown to be the most sensitive indicator of myocardial ischemia available in the clinical setting. It has potential for wide application for safely monitoring left ventricular function in patients in intensive care or under anesthesia.