NHLBI R01 HL073087到中正。

实验协议以下不同的协议，用于建立的，旨在调查的IR小鼠心脏非侵入性测量的可行性。其次是手术诱导缺血再灌注（IR，协议1）超声心动图在多个时间点红外恢复期间其次基线超声心动图成像。 协议1。左冠状动脉前降支（LAD）动脉红外：外科手术雄性C57BL / 6成年小鼠（8周龄; 24.5 ±1.5克，平均± SD卡，在哈伦技术）保持在标准实验室的住房条件获得议员和饮水自由采食 。小鼠麻醉后，利用腹腔注射氯胺酮（100毫克/公斤）和甲苯噻嗪（10mg/kg的），奠定了在一个温暖的手术台的混合物，插管endotracheally。推导出适当的麻醉老鼠的飞机是由脚趾捏反射停止和呼吸放缓。通过70％的乙醇清洗和高压灭菌消毒器械。离开无菌领域的任何文书，分别插入热珠为1分钟，然后再继续使用仪器灭菌。通风（小鼠，马萨诸塞州的波士顿哈佛器械）使用空气中的异氟醚的混合物，在适当的速率和潮气量。心脏电生理监测整个手术采用三导联心电图设置，和使用PC PowerLab系统软件（公元仪器）记录变化。 通过左侧开胸心脏​​访问。左肺缩回允许访问心包。左耳廓被提升到公开的冠脉法援署动脉，用7-0普理灵装在一个锥形针缝合这是孤立​​的的。缝合收紧了一块PE - 10管诱发可逆性缺血。法援署闭塞60分钟。 60分钟后，缝合被释放，让受伤的心肌灌注。再灌注成功后，胸部被关闭中断7-0普理灵缝合以及用5-0普理灵缝合皮肤切口。 整个手术，体温保持在36.7 ± 0.5 ° C，使用恒温手术台和直肠热探头监测。左室心肌缺血发作导致的面色苍白的色彩，可以直观地欣赏。被关闭胸腔，缝合，气管套管被中断使鼠标自己的呼吸。然后返回到动物笼上设置加热块到37 ° C。一旦恢复完成后，动物返回灭鼠动植物公园单位之前，超声心动图成像。所有的程序获得批准机构的实验室动物护理和使用委员会，美国俄亥俄州立大学（ILACUC）。 第2号议定书。 M型成像测定心功能和室壁运动异常检测协议为了评估在心脏功能和室壁运动异常的径向和纵向的变化，我们进行了红外成像采用高频率，高分辨率超声仪（视觉超音速公司，加拿大多伦多）。标准M型超声心动图参数，如墙的尺寸，在收缩，舒张和搏出量，射血分数（EF），短轴缩短率（FS），心输出量（CO），收缩期和舒张期内径，卷进行了评估使用内置的M -模式协议，各时间点（预IR，3和第7天天）。 议定书第3。 VevoStrain斑点跟踪算法协议 B型电影被收购，受到过程中使用内置VevoStrain算法执行应变分析。这使得评估的速度，位移，应变，和应变​​速率通过提供互动的情节和M型的图像，这是在控制面板中按一下所需的图标进行数据值的接口提供独立的无线电按钮。 斑点追踪评估株二维灰度电影循环在&gt; 275帧/秒的帧速率在LV短轴收购对于每一个实验中，至少有三个连续的心动周期和数字化存储在硬盘上在工作站上进行离线分析。我们用一个斑点跟踪算法纳入到Vevo2100。应变分析是由训练有素的观察员。感兴趣的区域覆盖整个横截面的最小的心内膜面积相应图像的心室。软件算法，然后自动分成6段的LV短轴斑点跟踪整个心动周期。质量跟踪，然后目视检查，如果它是令人满意，至少有五个部分，追踪被接受编辑。 议定书第4。多普勒血流测量协议研究二尖瓣关闭不全，并计算出左室收缩压（DP / DT）的变化率，多普勒血流检测协议使用。为此，能量多普勒血流速度剖面收购探头放置在二尖瓣返流喷射和主动脉喷射。其次是测量血流速度成像，获取值的参数，如高峰期，平均流速，峰值和平均压力梯度，速度时间积分和时间。 DP / DT的计算，二尖瓣返流速度剖面是用来衡量在早期收缩速度（速度剖面的最陡峭的斜坡，最大限度地减少负载的依赖）和相应的斜坡时间。最后，伯努利方程速度的压力转化为确定收缩压的增加速度。 超声心动图数据采集小鼠在清醒状态成像在室温为37℃，降低周围环境光线而俯卧左侧卧位位置由经验丰富的处理程序举行。心脏成像中的2 - D模式，在胸骨旁的长期和短期轴与一个1.0厘米的深度设置的意见，并在≥270帧/秒的帧速率在200毫米/秒的扫描速度得到一个M -模式图像所有测量均按照美国超声心动图学会提供的指引。 成像是在自觉小鼠执行串联心电图登记。结束收缩期被定义为最低LV地区。分部小号中国保监会和 S RAD曲线，然后通过整合适当的信号，从舒张末点开始建造，然后平均获得节段性平均应变曲线。然后，收缩末期株获得的平均应变曲线。 代表性的成果在高帧频（8千赫）收购了两家立体电影被用来估计高品质的心肌劳损。二维elastograms（应变图像），以及作为时间的函数的应变配置文件有助于欣赏红外功能的后果。上述做法导致可靠的检测以下参数： 标准的IR结果（俗称文献报道） <ul><li>左心室（LV）收缩<ul><li>受伤损害的功能的损失，导致心脏的收缩和舒张</li><li>在低压室的面积和质量的变化（肥大） </li></ul></li><li>左室舒张红外和跳动的心后红外等容相</li><li>妥协部门明智的室壁运动</li><li>彩色多普勒电影和速度剖面所揭示血流格局动荡</li><li> LV对球形形状的变化</li><li>损害射血分数</li><li>减毒缩短分数</li></ul>独特的后红外结果 （以前从未报道在小鼠的红外设置，但在人类已知的临床意义 ） <ul><li>有效返流口（主任） <ul><li>一个瓣膜无能的根本措施</li></ul></li><li>减少心肌株（圆周以及径向） <ul><li>心肌的强度和解剖变形的根本措施</li></ul></li><li>在LV的部门的异步<ul><li>一个固有的定期抽心的特点的根本措施</li></ul></li><li>室壁运动和对称性<ul><li>向量的幅度和方向的变化，表明在受影响站点的大小，方向和对称</li></ul></li><li>二尖瓣和主动脉尺寸<ul><li>二尖瓣口和主动脉内径的变化</li></ul></li><li>二尖瓣关闭不全<ul><li>血液的回流，从LV到左心房，由于不完全封闭二尖瓣单张</li></ul></li></ul><ul><li>部门明智的变化幅度的径向（SRAD）和环（Scir）应变</li><li>应变率随其变化规律显着变化，相对于前红外数据的变化</li><li>同步LV的部门，按美国超声心动图学会</li><li>协会心室心肌僵硬机械的同步和降低心肌的力量，通过组织多普勒和应变成像评估</li><li>电影描绘损害运动的红外受影响的网站（缓慢和非对称）所示的矢量的幅度和方向的变化</li><li>内部直径二尖瓣ORIF冰和主动脉</li></ul><img src="/files/ftp_upload/1781/1781fig1.1.jpg" alt="图1我" /> 图心肌劳损。1I测量舒张末期充分放松，通过最短的载体供应量（M1）所示<img src="/files/ftp_upload/1781/1781fig1.2.jpg" alt="图1二" /> 图1ii心肌劳损测量：LV是承包向量的长度和方向显示，损伤部位（绿点），有限的收缩量（M2 ） <img src="/files/ftp_upload/1781/1781fig1.3.jpg" alt="图1三" /> 图心肌劳损。1iii测量：最终收缩，通过最短的向量（M3）所示的全面收缩<img src="/files/ftp_upload/1781/1781fig1.4.jpg" alt="图1四" /> 图心肌劳损。1iv测量：在舒张的长轴（M4 ） <img src="/files/ftp_upload/1781/1781fig1.5.jpg" alt="图1 V" /> 图1V心肌径向应变（RAD）的测量：彩色编码的曲线代表在各自的彩色点Fig1.i - IV图像株（M5 ） <img src="/files/ftp_upload/1781/1781fig1.6.jpg" alt="图1六" /> 图1vi心肌周向应变测量：（CIR）彩色编码的曲线代表在各自的彩色点Fig1.i - IV图像株（M6） 图1。 B模式电影可视化舒张末期（ED）和最终收缩（ES）和左室腔大小后IR的变化。 B模式的图像，以确定的二维左心室（LV）圆周应变 （中国保监会）和径向应变 （RAD）斑点追踪超声心动图。 VevoStrain斑点跟踪算法，以观察心肌的运动，轴向和胸骨旁长轴的意见，证明在受损的心肌损伤部位的向量的大小和方向的矢量描绘。 径向和纵向上的基线鼠标和鼠标后红外day7株。彩色编码显示不同的颜色编码在网站上的基线（前IR）心肌的应变型材和处理（后IR，day7）心中。 LV的左心室，右室右心室，S RAD径向应变，S CIR周向应变。 <img src="/files/ftp_upload/1781/1781fig2.jpg" alt="图2" /> 图2。心肌部门同步 。 分析的基础上的应变数据前和后的IR。 LV的划分成六个部门（1 =基础后，4 =前基肥，2 =中旬后，5 =前中期，3 =后的顶点，6 =前顶点）根据美国超声心动图学会。心室机械同步协会组织多普勒和应变成像评估心肌僵硬的验证。 彩色编码图像面板，显示时间值的行业，从1-6高峰以毫秒为单位的相应部门。前红外光谱和红外后在图表上的径向和纵向synchronicities。上图的颜色对应到相应的部门色彩。 <img src="/files/ftp_upload/1781/1781fig3.1.jpg" alt="图3我" /> 图3i的解剖测量：在小鼠心脏二尖瓣关闭不全孔口直径（重复测量的蓝线），样本量在主动脉（黄线）（M8 ） <img src="/files/ftp_upload/1781/1781fig3.2.jpg" alt="图3二" /> 图3ii，在小鼠心脏，上向前和二尖瓣（M9）低的落后流量返流流概况<img src="/files/ftp_upload/1781/1781fig3.3.jpg" alt="图3三" /> 图3iii。小鼠心脏主动脉（M10）出流速剖面<img src="/files/ftp_upload/1781/1781fig3.4.jpg" alt="图3四" /> 图3iv。二尖瓣返流孔口，AO =主动脉，LA = LV的左心房，左心室，R =半径（M11） 图3。二尖瓣阀V反流分数（RF）。 返流分数的测量超声心动图图像面板（RF）。测量主动脉内径（AOD）和二尖瓣口直径（MVD），显示安置在返流喷射和主动脉的样本量。这些测量提供返流的速度剖面和升主动脉流量基线的上方和下方速度剖面表明，前进和后退到LV血流回左心房。射频（％）计算公式，RF = MV修正案* VTI的MV在舒张期喷射 - 敖修正案* VTI公司在收缩）敖喷气* 100 / MV CSA * VTI公司的MV。 量化返流后IR小鼠指标反刍二尖瓣返流分数的分数。二尖瓣有效返流口的变化（主任）后的IR由于球形的LV。代表彩色多普勒超声图像描绘了左心房的血液流入到LV。扩大血流口表示紊流和流速异常增加。主任表示瓣膜无能。流速别名。脉冲波是利用，以造福在决定转换层湍流。主任计算公式，主任=流量/ VMAX = 2πR2 VA / VMAX，VA =别名速度，r =孔口半径，VMAX =最大速度。 <img src="/files/ftp_upload/1781/1781fig4.1.jpg" alt="图4我" /> 图4I。预红外鼠标的功能参数的测量。软制品跟踪，红色垂直线计算的参数=舒张，绿色的垂直线收缩（M12） <img src="/files/ftp_upload/1781/1781fig4.2.jpg" alt="图4二" /> 图4ii测量后的红外鼠标的功能参数。软制品跟踪，红色垂直线计算的参数=舒张，绿色的垂直线收缩（M13） 图4。心室收缩压（DP / DT）的变化率：前和后的IR。 相关的射血分数（EF）与DP / DT。图像面板上显示的M -模式，从基本功能测量。 随着时间的推移心脏收缩的歧视;条形图显示DP / DT后的IR。这说明一个参数的测量提供了到其他临床资料。 <img src="/files/ftp_upload/1781/1781fig5.jpg" alt="图5" /> 图5。短轴电影展示红外预应变测量。 从心脏的胸骨，以期在小鼠心脏前IR形态可视化获得的超声心动图电影。 <img src="/files/ftp_upload/1781/1781fig6.jpg" alt="图6" /> 图6。短轴电影演示后IR LV应变测量 代表鼠标LV轴向电影追溯到内膜组织的应变向量证明在考虑测量特定点。 <img src="/files/ftp_upload/1781/1781fig7.jpg" alt="图7" /> 图7。胸骨旁长轴彩色多普勒电影 彩色多普勒血流影片展示了血泵，在左心房通过二尖瓣进入LV舒张和血液泵出心脏在收缩阶段通过主动脉与流的蓝色和红色对网（BART）方向超声探头。

基础上使用测量数据的应变斑点跟踪算法观察员大部分是由软件进行分析的依赖相对较少。然而，观察员应小心在跟踪这取决于更多的经验在B模式电影外膜和心内膜寄宿。此外，M模式的分析和测量速度剖面，也是最小的观察员依赖。然而，在压力的上升和次测量的测量，观察员在测量过程中需要非常小心注意，因为压力直接取决于与伯努利小号公式中，甚至在测量少量的错误可以表达的峰值速度的平方DP / DT测量总误差平方的效果。此外，反流孔口不一定是整个收缩不断，这可能会影响返流严重程度的估计。高剂量的麻醉可能会导致在急剧减少影响其他功能参数的小数缩短。因此，标准的使用镇静，重要的是更好的结果。大多数参数都可以用其他方式，例如，MRI标签可以测量的二维和三维株。然而，超声心动图是用户更加友好。

<table border="1">
<tbody>
<tr>
<td>Material Name</td>
<td>Type</td>
<td>Company</td>
<td>Catalogue Number</td>
</tr>
<tr>
<td>Vevo2100</td>
<td>&nbsp;</td>
<td>VisualSonics, Inc., Canada</td>
<td>SN2100-0032</td>
</tr>
<tr>
<td>Ventilation device</td>
<td>&nbsp;</td>
<td>Harvard Apparatus, MA</td>
<td>n/a</td>
</tr>
<tr>
<td><a href="http://www.adinstruments.com/products/software/research/LabChart-Software/" target="_blank">PC Powerlab software</a></td>
<td>&nbsp;</td>
<td><a href="http://www.adinstruments.com/" target="_blank">AD Instruments</a></td>
<td>n/a</td>
</tr>
<tr>
<td>Isoflurane</td>
<td>&nbsp;</td>
<td>VEDCO, Inc., MO</td>
<td>5260-04-12</td>
</tr>
<tr>
<td>Aquasonic gel 100</td>
<td>&nbsp;</td>
<td>Parker Lab. Inc., NJ</td>
<td>01-02</td>
</tr>
</tbody>
</table>

high-frequency high-resolution echocardiography: first evidence on non-invasive repeated measure of myocardial strain, contractility, and mitral regurgitation in the ischemia-reperfused murine heart

手术在其中遭受反复成像监测在关键的临床意义功能参数的时空变化的小鼠心缺血再灌注（IR）。二维电影获得高帧频（8千赫），被用来估计高品质的心肌劳损。二维elastograms（应变图像），以及应变型材，可视化。结果强大的定量评估心脏事件的IR引起的变化，包括左心室（LV）收缩，左室舒张和等容在完整的小鼠中击败前红外光谱和红外后心中阶段。此外，损害部门明智的室壁运动和心肌梗死的解剖变形可视化。 elastograms是唯一能够提​​供以下参数的信息，除了标准，被称为是通过在老鼠心肌梗死的影响生理指标：内部二尖瓣口和主动脉的直径，有效反流口，心肌劳损（圆周以及径向），彩色多普勒电影和速度剖面，在LV部门的不同步性，并证明慢和非对称的壁运动向量的长度和方向的变化显示，在血液流动格局的动荡。这项工作强调了如何进行这种分析的可视化示范。

Watch this Scientific Journal Video about High-frequency High-resolution Echocardiography: First Evidence on Non-invasive Repeated Measure of Myocardial Strain, Contractility, and Mitral Regurgitation

High-frequency High-resolution Echocardiography: First Evidence on Non-invasive Repeated Measure of Myocardial Strain, Contractility, and Mitral Regurgitation in the Ischemia-reperfused Murine Heart 

高频多普勒超声是评价局部心肌功能的新技术。这项工作提出证据证明这种多功能成像平台的适用性，心肌劳损，DP / dt和二尖瓣关闭不全缺血再灌注（IR）小鼠心脏的重复测量。

高频超声心动图：非侵入性的反复测量小鼠心脏缺血再灌注心肌劳损，收缩力，二尖瓣关闭不全的第一个证据

Ischemia-reperfusion (IR) was surgically performed in murine hearts which were then subjected to repeated imaging to monitor temporal changes in ...

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High-frequency High-resolution Echocardiography: First Evidence on Non-invasive Repeated Measure of Myocardial Strain, Contractility, and Mitral Regurgitation in the Ischemia-reperfused Murine Heart

23.9K 次观看.  The Ohio State University. 高频多普勒超声是评价局部心肌功能的新技术。这项工作提出证据证明这种多功能成像平台的适用性，心肌劳损，DP / dt和二尖瓣关闭不全缺血再灌注（IR）小鼠心脏的重复测量。

视频: High-frequency High-resolution Echocardiography: First Evidence on Non-invasive Repeated Measure of Myocardial Strain, Contractility, and Mitral Regurgitation in the Ischemia-reperfused Murine Heart 

Murine Echocardiography and Ultrasound Imaging

Rodent models of cardiac pathophysiology represent a valuable research tool to investigate mechanism of disease as well as test new therapeutics.1 Echocardiography provides a powerful, non-invasive tool to serially assess cardiac morphometry and function in a living animal.2 However, using this technique on mice poses unique challenges owing to the small size and rapid heart rate of these animals.3 Until recently, few ultrasound systems were capable of performing quality echocardiography on mice, and those generally lacked the image resolution and frame rate necessary to obtain truly quantitative measurements. Newly released systems such as the VisualSonics Vevo2100 provide new tools for researchers to carefully and non-invasively investigate cardiac function in mice. This system generates high resolution images and provides analysis capabilities similar to those used with human patients. Although color Doppler has been available for over 30 years in humans, this valuable technology has only recently been possible in rodent ultrasound.4,5 Color Doppler has broad applications for echocardiography, including the ability to quickly assess flow directionality in vessels and through valves, and to rapidly identify valve regurgitation. Strain analysis is a critical advance that is utilized to quantitatively measure regional myocardial function.6 This technique has the potential to detect changes in pathology, or resolution of pathology, earlier than conventional techniques. Coupled with the addition of three-dimensional image reconstruction, volumetric assessment of whole-organs is possible, including visualization and assessment of cardiac and vascular structures. Murine-compatible contrast imaging can also allow for volumetric measurements and tissue perfusion assessment.

This video demonstrates use of a rail-mounted high-frequency ultrasound probe to perform echocardiography on an anesthetized mouse. The methods describe both conventional two-dimensional and M-mode measurements of cardiac function in addition to newer, more powerful tools such as color Doppler, strain analysis, as well as general and targeted contrast imaging.

小鼠超声心动图和超声成像

Rodent models of cardiac pathophysiology represent a valuable research tool to investigate mechanism of disease as well as test new therapeutics.1  ...

科研

医学

Magnetic Resonance Derived Myocardial Strain Assessment Using Feature Tracking

Purpose: An accurate and practical method to measure parameters like strain in myocardial tissue is of great clinical value, since it has been shown, that strain is a more sensitive and earlier marker for contractile dysfunction than the frequently used parameter EF. Current technologies for CMR are time consuming and difficult to implement in clinical practice. Feature tracking is a technology that can lead to more automization and robustness of quantitative analysis of medical images with less time consumption than comparable methods.
Methods: An automatic or manual input in a single phase serves as an initialization from which the system starts to track the displacement of individual patterns representing anatomical structures over time. The specialty of this method is that the images do not need to be manipulated in any way beforehand like e.g. tagging of CMR images.
Results: The method is very well suited for tracking muscular tissue and with this allowing quantitative elaboration of myocardium and also blood flow.
Conclusions: This new method offers a robust and time saving procedure to quantify myocardial tissue and blood with displacement, velocity and deformation parameters on regular sequences of CMR imaging. It therefore can be implemented in clinical practice.

An accurate and practical method to measure parameters like strain in myocardial tissue is of great clinical value, since it has been shown, that strain is a more sensitive and earlier marker for contractile dysfunction than the frequently used parameter EF.

磁共振衍生的心肌劳损评估使用特征跟踪

Purpose: An accurate and practical method to measure parameters like strain in myocardial tissue is of great clinical value, since it has been shown, that ...

Myocardial Infarction and Functional Outcome Assessment in Pigs

Introduction of newly discovered cardiovascular therapeutics into first-in-man trials depends on a strictly regulated ethical and legal roadmap. One important prerequisite is a good understanding of all safety and efficacy aspects obtained in a large animal model that validly reflect the human scenario of myocardial infarction (MI). Pigs are widely used in this regard since their cardiac size, hemodynamics, and coronary anatomy are close to that of humans. Here, we present an effective protocol for using the porcine MI model using a closed-chest coronary balloon occlusion of the left anterior descending artery (LAD), followed by reperfusion. This approach is based on 90 min of myocardial ischemia, inducing large left ventricle infarction of the anterior, septal and inferoseptal walls. Furthermore, we present protocols for various measures of outcome that provide a wide range of information on the heart, such as cardiac systolic and diastolic function, hemodynamics, coronary flow velocity, microvascular resistance, and infarct size. This protocol can be easily tailored to meet study specific requirements for the validation of novel cardioregenerative biologics at different stages (i.e. directly after the acute ischemic insult, in the subacute setting or even in the chronic MI once scar formation has been completed). This model therefore provides a useful translational tool to study MI, subsequent adverse remodeling, and the potential of novel cardioregenerative agents.

This protocol describes the porcine myocardial infarction (MI) model using a 90 min closed-chest coronary balloon occlusion of the left anterior descending artery (LAD), followed by reperfusion. Furthermore, the protocol for several outcome parameters, such as cardiac function, hemodynamics, microvascular resistance, and infarct size, are also presented.

心肌梗死和功能预后评估的猪

Introduction of newly discovered cardiovascular therapeutics into first-in-man trials depends on a strictly regulated ethical and legal roadmap. One ...

A Murine Model of Myocardial Ischemia-reperfusion Injury through Ligation of the Left Anterior Descending Artery

Acute or chronic myocardial infarction (MI) are cardiovascular events resulting in high morbidity and mortality. Establishing the pathological mechanisms at work during MI and developing effective therapeutic approaches requires methodology to reproducibly simulate the clinical incidence and reflect the pathophysiological changes associated with MI. Here, we describe a surgical method to induce MI in mouse models that can be used for short-term ischemia-reperfusion (I/R) injury as well as permanent ligation. The major advantage of this method is to facilitate location of the left anterior descending artery (LAD) to allow for accurate ligation of this artery to induce ischemia in the left ventricle of the mouse heart. Accurate positioning of the ligature on the LAD increases reproducibility of infarct size and thus produces more reliable results. Greater precision in placement of the ligature will improve the standard surgical approaches to simulate MI in mice, thus reducing the number of experimental animals necessary for statistically relevant studies and improving our understanding of the mechanisms producing cardiac dysfunction following MI. This mouse model of MI is also useful for the preclinical testing of treatments targeting myocardial damage following MI.

We introduce a surgical method to induce experimental ischemia/reperfusion (I/R) injury to simulate myocardial infarction (MI) in mouse models that allows for more clarity in positioning of the ligation on the left anterior descending artery (LAD) to increase the reproducibility of MI experiments in mice.

心肌缺血再灌注损伤的通过左前降支结扎小鼠模型

Acute or chronic myocardial infarction (MI) are cardiovascular events resulting in high morbidity and mortality. Establishing the pathological mechanisms ...

Murine Isolated Heart Model of Myocardial Stunning Associated with Cardioplegic Arrest

The following protocol is of use to evaluate impaired cardiac function or myocardial stunning following moderate ischemic insults. The technique is useful for modeling ischemic injury associated with numerous clinically relevant phenomenon including cardiac surgery with cardioplegic arrest and cardiopulmonary bypass, off-pump CABG, transplant, angina, brief ischemia, etc. The protocol presents a general method to model hypothermic hyperkalemic cardioplegic arrest and reperfusion in rodent hearts focusing on measurement of myocardial contractile function. In brief, a mouse heart is perfused in langendorff mode, instrumented with an intraventricular balloon, and baseline cardiac functional parameters are recorded. Following stabilization, the heart is then subject to brief infusion of a cardioprotective hypothermic cardioplegia solution to initiate diastolic arrest. Cardioplegia is delivered intermittently over 2 hr. The heart is then reperfused and warmed to normothermic temperatures and recovery of myocardial function is monitored. Use of this protocol results in reliable depressed cardiac contractile function free from gross myocardial tissue damage in rodents.

The goal of this protocol to assess myocardial stunning following ischemic cardioplegic arrest in rodents.

心肌顿抑相关的小鼠离体心脏模型心脏停搏

The following protocol is of use to evaluate impaired cardiac function or myocardial stunning following moderate ischemic insults. The technique is useful ...

Murine Echocardiography of Left Atrium, Aorta, and Pulmonary Artery

The present methodology teaches the investigator how to measure and use the LAV as a surrogate of chronic elevations in Left Ventricular diastolic pressure through echocardiography, as well as to obtain measurements of the Aorta and PA diameter in mice.
Mice older than 10 d of age can be analyzed using the present technique. The technique is composed of 3 main steps: set-up, image acquisition, and image analysis. The set-up step consists of getting the mouse anesthetized with 1% isoflurane, shaving it, and taping it in a supine position to a heated EKG board where the image acquisition will take place. The image acquisition step consists of learning to identify the cardiac structures and obtaining all the required images with its correspondent probe and axis in order to be able to calculate volumes and diameters. The image analysis step consists of measuring the previously acquired images with the aid of computer software.
Advantages of the proposed technique include a fast (15 min) procedure that would allow the researcher to evaluate interventions in a non-invasive, non-terminal approach and therefore follow the same mouse over time; each mouse can be used as its own control. This fact plus having the same operator perform all the acquisition and analysis for the entire experiment minimizes the limitation of operator-dependency. The present methodology is useful for mouse researchers in cardiovascular and pulmonary medicine.

The following protocol describes the methodology for the acquisition and analysis of echocardiographic images used to obtain the Left Atrial Volume (LAV), Aorta (Ao) diameter, and Pulmonary Artery (PA) diameter in mice. This technique is a non-invasive, non-terminal procedure that allows assessment of the cardiopulmonary function.

左心房，主动脉和肺动脉的超声心动图小鼠

The present methodology teaches the investigator how to measure and use the LAV as a surrogate of chronic elevations in Left Ventricular diastolic ...

Electrophysiological Assessment of Murine Atria with High-Resolution Optical Mapping

Recent genome-wide association studies targeting atrial fibrillation (AF) have indicated a strong association between the genotype and electrophysiological phenotype in the atria. That encourages us to utilize a genetically-engineered mouse model to elucidate the mechanism of AF. However, it is difficult to evaluate the electrophysiological properties in murine atria due to their small size. This protocol describes the electrophysiological evaluation of atria using an optical mapping system with a high temporal and spatial resolution in Langendorff perfused murine hearts. The optical mapping system is assembled with dual high-speed complementary metal oxide semiconductor cameras and high magnification objective lenses, to detect the fluorescence of a voltage-sensitive dye and Ca2+ indicator. To focus on the assessment of murine atria, optical mapping is performed with an area of 2 mm &#215; 2 mm or 10 mm x 10 mm, with a 100 &#215; 100 resolution (20 &#181;m/pixel or 100 &#181;m/pixel) and sampling rate of up to 10 kHz (0.1 ms) at maximum. A 1-French size quadripolar electrode pacing catheter is placed into the right atrium through the superior vena cava avoiding any mechanical damage to the atrium, and pacing stimulation is delivered through the catheter. An electrophysiological study is performed with programmed stimulation including constant pacing, burst pacing, and up to triple extrastimuli pacing. Under a spontaneous or pacing rhythm, the optical mapping recorded the action potential duration, activation map, conduction velocity, and Ca2+ transient individually in the right and left atria. In addition, the programmed stimulation also determines the inducibility of atrial tachyarrhythmias. Precise activation mapping is performed to identify the propagation of the excitation in the atrium during an induced atrial tachyarrhythmia. Optical mapping with a specialized setting enables a thorough electrophysiological evaluation of the atrium in murine pathological models.

This protocol describes the electrophysiological evaluation of murine atria utilizing an optical mapping system with a high temporal and spatial resolution, including dual recordings of the membrane voltage and Ca2+ transient under programmed stimulation through a specialized electrode catheter.

高分辨率光学制图对小鼠心房电生理的评价

Recent genome-wide association studies targeting atrial fibrillation (AF) have indicated a strong association between the genotype and ...

A Cryoinjury Model to Study Myocardial Infarction in the Mouse

The use of animal models is essential for developing new therapeutic strategies for acute coronary syndrome and its complications. In this article, we demonstrate a murine cryoinjury infarct model that generates precise infarct sizes with high reproducibility and replicability. In brief, after intubation and sternotomy of the animal, the heart is lifted from the thorax. The probe of a handheld liquid nitrogen delivery system is applied onto the myocardial wall to induce cryoinjury. Impaired ventricular function and electrical conduction can be monitored with echocardiography or optical mapping. Transmural myocardial remodeling of the infarcted area is characterized by collagen deposition and loss of cardiomyocytes. Compared to other models (e.g., LAD-ligation), this model utilizes a handheld liquid nitrogen delivery system to generate more uniform infarct sizes.

This article demonstrates a model to study cardiac remodeling after myocardial cryoinjury in mice.

研究小鼠心肌梗死的低温损伤模型

The use of animal models is essential for developing new therapeutic strategies for acute coronary syndrome and its complications. In this article, we ...

An Image Guided Transapical Mitral Valve Leaflet Puncture Model of Controlled Volume Overload from Mitral Regurgitation in the Rat

Mitral regurgitation (MR) is a widely prevalent heart valve lesion, which causes cardiac remodeling and leads to congestive heart failure. Though the risks of uncorrected MR and its poor prognosis are known, the longitudinal changes in cardiac function, structure and remodeling are incompletely understood. This knowledge gap has limited our understanding of the optimal timing for MR correction, and the benefit that early versus late MR correction may have on the left ventricle. To investigate the molecular mechanisms that underlie left ventricular remodeling in the setting of MR, animal models are necessary. Traditionally, the aorto-caval fistula model has been used to induce volume overload, which differs from clinically relevant lesions such as MR. MR represents a low-pressure volume overload hemodynamic stressor, which requires animal models that mimic this condition. Herein, we describe a rodent model of severe MR in which the anterior leaflet of the rat mitral valve is perforated with a 23G needle, in a beating heart, with echocardiographic image guidance. The severity of MR is assessed and confirmed with echocardiography, and the reproducibility of the model is reported.&#160;&#160;

A rodent model of left heart volume overload from mitral regurgitation is reported. Mitral regurgitation of controlled severity is induced by advancing a needle of defined dimensions into the anterior leaflet of the mitral valve, in a beating heart, with ultrasound guidance.&#160;

大鼠中三极重化控制体积过载的图像引导透射斜线阀传单穿刺模型

Mitral regurgitation (MR) is a widely prevalent heart valve lesion, which causes cardiac remodeling and leads to congestive heart failure. Though the ...

Morphological and Functional Assessment of the Right Ventricle Using 3D Echocardiography

Traditionally, it was believed that the right side of the heart has a minor role in circulation; however, more and more data suggest that right ventricular (RV) function has strong diagnostic and prognostic power in various cardiovascular disorders. Due to its complex morphology and function, assessment of the RV by conventional two-dimensional echocardiography is limited: the everyday clinical practice usually relies on simple linear dimensions and functional measures. Three-dimensional (3D) echocardiography overcame these limitations by providing volumetric quantification of the RV free of geometrical assumptions. Here, we offer a step-by-step guide to obtain and analyze 3D echocardiographic data of the RV using the leading commercially available software. We will quantify 3D RV volumes and ejection fraction. Several technical aspects may help to improve the quality of RV acquisition and analysis as well, which we present in a practical manner. We review the current opportunities and the limiting factors of this method and also highlight the potential applications of 3D RV assessment in current clinical practice.

Here, we provide a step-by-step acquisition and analysis protocol for the 3D volumetric assessment of the right ventricle, mainly focusing on the practical aspects that maximize the feasibility of this technique.