Nos gustaría agradecer al Dr. Corey Reynolds y el ratón BCM núcleo fenotipo por su ayuda de expertos con este proyecto y el acceso a las instalaciones de clase. XHTW es un WM Keck Foundation Distinguished Scholar jóvenes en la investigación médica, y también es apoyado por el NIH / NHLBI subvenciones R01-R01 y HL089598 HL091947, y Asociación de Distrofia Muscular de subvención # 69238. Este trabajo también es apoyado en parte por la Fundación Alianza Leducq de CaMKII en el Corazón de señalización.

1. Los ratones preparando para estudios de imágenes <ol><li> Antes de los estudios de imagen, anestesiar el ratón (2% isoflurano se mezcla con 0,5 l / min 100% O 2) en la cámara de inducción. Asegúrese de filtro de gases residuales para la seguridad del operador. Quitar el animal de la cámara de inducción y el uso de máquinas de cortar el cabello para afeitar los pelos del cuello a la altura del pecho medio. A continuación, eliminar el vello del cuerpo restante con crema depilatoria. Esta preparación puede llevar a cabo un día antes de los estudios por imágenes para minimizar el potencial de las respuestas al estrés no deseado en los ratones. </li><li> Aplicar duralube gel en los dos ojos para prevenir la sequedad de la esclerótica (evitar el contacto con la córnea con el aplicador de gel). Coloque el ratón anestesiado en posición supina sobre una almohadilla de calefacción integrado con derivaciones del ECG con el fin de mantener la temperatura corporal. </li><li> Coloque el hocico en un cono de la nariz conectada al sistema de anestesia para mantener un nivel de sedación en estado estable durante todo el procedimiento (1,0% a 1,5% isoflurano se mezcla con 0,5 l / min 100% O 2). Realizar una pizca dedo del pie o la cola para confirmar la sedación. Si es necesario, el nivel de anestesia puede ser ajustada para obtener una frecuencia cardíaca de 450 ± 50 latidos por minuto (ppm). </li><li> Suavemente inserte una sonda rectal (después de la lubricación) para controlar y ajustar continuamente la temperatura del cuerpo a través de la almohadilla. Es importante mantener la temperatura corporal dentro de un rango estrecho (37,0 ° C ± 0,5 ° C), ya que incluso cambios moderados en la temperatura y la frecuencia cardiaca afectar la función cardiaca en ratones. </li><li> Aplique el gel de electrodos para las cuatro patas y con cinta adhesiva a los electrodos de ECG. </li></ol> 2. Sistólica evaluar la función del corazón <ol><li> Para iniciar este procedimiento, aplicar una capa de gel de ultrasonido precalentado en el pecho, sobre todo el área que cubre el corazón. Gel debe ser calentada a la temperatura corporal aproximado. Un volumen de gel frío rápidamente puede aumentar la tasa de pérdida de temperatura corporal. Evite las burbujas de aire en el gel, que puede interferir con las imágenes de ultrasonido. </li><li> Inmovilizar el ratón en una posición ligeramente hacia arriba (hasta la cabeza) en un ligero ángulo. El uso de un micromanipulador, inmovilizar la sonda de ultrasonido con un ángulo de 90 ° entre la sonda y el corazón. </li><li> Para empezar a hacer el eje corto mediciones ecocardiográficas, baje la sonda en el tórax paraesternalmente. Evite colocar la sonda directamente sobre el esternón o en la piel, ya que esto distorsiona la señal. </li><li> En primer lugar, vamos a realizar en dos dimensiones (2D) de imágenes (&quot;B-mode &#39;) para obtener una vista a lo largo del eje corto paraesternal. Ajuste el área de visualización de la sonda para obtener una imagen completa, dependiendo del tamaño del corazón del animal. </li><li> Una imagen adecuada en esta orientación se incluyen el ventrículo izquierdo y una porción pequeña de la pared del ventrículo derecho. La flecha (que se muestra en el video) indica que los músculos papilares anterolateral y posteromedial, las paredes anterior y posterior del ventrículo izquierdo, la pared del tabique intraventricular, y una porción pequeña de la pared del ventrículo derecho. Durante estas medidas, prestando especial atención a los posibles alteraciones de la motilidad de la pared (por ejemplo, hipocinesia, akinasia, asincronía) o aneurismas. </li><li> A continuación, vamos a utilizar Ecocardiografía en modo M, que proporciona un 1-dimensión (1D) punto de vista, para obtener mediciones muy bien de dimensiones y la contractilidad cardíaca. Guardar las imagenes adquiridas para su posterior evaluación de los parámetros de la función sistólica del ventrículo izquierdo. </li></ol> 3. Evaluación de la función diastólica del corazón <ol><li> Mientras siguen viendo el eje corto paraesternal, podemos realizar Doppler tisular (TDI) para medir la velocidad de movimiento del miocardio. La región de interés está marcado para incluir una pared posterior del ventrículo izquierdo para la evaluación del eje radial. La forma de onda obtenida tendrá cuatro picos para evaluar la función diastólica: TRIV, E &#39;, A&#39;, y IVCT. S &#39;representa la velocidad sistólica. (Figura 3B) Estos parámetros se describen más adelante en la sección de resultados representativos. </li><li> La onda de pulso Doppler (PWD) se puede utilizar para medir la velocidad del flujo sanguíneo en un área pequeña, a una profundidad específica en el tejido miocárdico. A la imagen del patrón de flujo de trans-mitral, la inclinación del animal hacia atrás en posición de Trendelenburg. Inclinación de la sonda hacia arriba, de tal manera que la sonda es ortogonal con el ápice del corazón. </li><li> Ahora aumentar el nivel de isoflurano para reducir el ritmo cardíaco a 300-350 latidos por minuto, lo que hará más lento el movimiento de la válvula mitral. Para los estudios de comparación, es importante para mantener tasas similares entre los animales del corazón. </li><li> Visualizar los movimientos de la válvula mitral como punto de referencia para medir el flujo en la válvula. Coloque el volumen de la muestra en la punta de la válvula mitral. </li><li> Medir los patrones de flujo a través de la válvula mitral con personas con discapacidad. Dos ondas se caracterizan por ser visto, uno en representación de llenado pasivo del ventrículo (a principios de [E] de onda), yconsistente con el relleno activo con la sístole atrial (auricular [A] de onda) una. En un corazón sano, la velocidad de la onda E es ligeramente mayor que la de la onda A (Figura 3C). </li><li> Una vez que todas las mediciones se han completado, quitar el gel de los electrodos (por limpie suavemente con gasas estándar) y las restricciones de los animales. Deje que el animal suelto para recuperar la cima de la plataforma de ECG se calienta en una posición vertical y apagar la anestesia. Cuando el ratón se despierta, vuelve a su jaula. </li></ol> 4. Representante Resultados ecocardiografía transtorácica No invasiva estudios ecocardiográficos se pueden utilizar para evaluar la morfología y función del ventrículo izquierdo en modelos murinos de enfermedad cardíaca. 4,5 Esta técnica es ampliamente utilizado y ofrece una alternativa a los procedimientos de la terminal para evaluar la función del VI, como intracardiaca bucle presión-volumen measurements.8 o el ex vivo modelo de trabajo del corazón. 9 Evaluación de las dimensiones de la cámara baja tensión por transtorácica Ecocardiografía en modo M permite la detección de un aumento anormal cámara del VI o mayor espesor de la pared en varios modelos de enfermedades del corazón. 5 Por lo tanto, la ecocardiografía transtorácica, en combinación con la onda de pulso Doppler , constituye una vía integral para la evaluación no invasiva de la función sistólica y diastólica cardiaca en ratones. <img src="/files/ftp_upload/1738/1738fig1.jpg" alt="Figura 1" /> Figura 1. Resumen de Vevo Resolución 770 de alta in vivo Micro-Imaging System de Ecocardiografía y Doppler. (A) Utilizamos el sistema ferroviario VisualSonics integrada con la unidad de monitorización fisiológica, tabla de EKG, y RMV cabeza 30MHz exploración. (B) El ratón está posicionado correctamente y moderación en el tablero de calefacción integrado con electrodos de ECG (color oro). Los cuatro miembros se graban en los electrodos de ECG. (CD) Fotografías que muestran ángulos apropiados para la onda de pulso Doppler para obtener mediciones de la función diastólica, como se describe en la sección 4 del protocolo. Orientación de la sonda de medición de la función sistólica se muestran en el protocolo de vídeo. <img src="/files/ftp_upload/1738/1738fig2.jpg" alt="Figura 2" /> Figura 2. Representante 2D imágenes de ecocardiografía (modo B). (A) para-esternal de eje corto que muestra la parte anterior del ventrículo izquierdo (OI) y posterior paredes (PW), la pared del tabique intraventricular (SW), y la pared lateral (LW). El diámetro de la luz del ventrículo izquierdo puede ser medido como el diámetro interno del ventrículo izquierdo (LVID). El asterisco indica que el músculo papilar posteromedial. (B) apical de cuatro cámaras, con un área de visión sobre la válvula mitral para la determinación de E / A velocidades máximas. MVal, valva de la válvula mitral anterior; folleto MVPL, la válvula mitral posterior; VD: ventrículo derecho, ventrículo izquierdo, del ventrículo izquierdo. <img src="/files/ftp_upload/1738/1738fig3.jpg" alt="Figura 3" /> Figura 3. Adquisición y cuantificación de los datos de ecocardiografía y Doppler. Esta cifra contiene imágenes representativas de los datos obtenidos correspondientes a las imágenes de ecocardiografía 2D presenta en la Figura 2. (A) en modo M trazado con líneas que indican fin de sístole (ESD) y diámetros diastólicos (EDD). LVAWD / S, el espesor del ventrículo izquierdo de la pared anterior (la diástole / sístole); LVPWD / S, a la izquierda de espesor de la pared ventricular posterior (diástole / sístole). (B) Representante de los trazados de Doppler tisular de la pared posterior del ventrículo izquierdo. TRIS: tiempo de relajación isovolumétrica; IVCT tiempo, la contracción isovolumétrica. El E &#39;corresponde a la onda de movimiento del anillo mitral durante la diástole temprana de llenado del ventrículo izquierdo, y el A&#39; ola se origina en la sístole auricular a finales de llenado del ventrículo izquierdo. S &#39;representa la velocidad sistólica. (C) la onda de pulso registro Doppler de la válvula mitral folleto ofrece consejos mitral patrones de velocidad de entrada de la que puede ser la velocidad diastólica precoz (E), velocidad diastólica tardía con contracción diastólica (A), y la relación E / A deriva. La TRIV es también una variable útil para caracterizar la función diastólica y las presiones de llenado. ET indica el tiempo de eyección.

<ol>
	<li>Zhang, T. M. a. i. e. r., S, L., Dalton, N. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+deltaC+isoform+of+CaMKII+is+activated+in+cardiac+hypertrophy+and+induces+dilated+cardiomyopathy+and+heart+failure.">The deltaC isoform of CaMKII is activated in cardiac hypertrophy and induces dilated cardiomyopathy and heart failure.</a> Circ Res. 92 (8), 912-912 (2003).</li><li>Srivastava, D., Thomas, T., Lin, Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+cardiac+mesodermal+and+neural+crest+development+by+the+bHLH+transcription+factor,+dHAND.">Regulation of cardiac mesodermal and neural crest development by the bHLH transcription factor, dHAND.</a> Nat Genet. 16 (2), 154-154 (1997).</li><li>Sood, S., Chelu, M. G., van Oort, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intracellular+calcium+leak+due+to+FKBP12.6+deficiency+in+mice+facilitates+the+inducibility+of+atrial+fibrillation.">Intracellular calcium leak due to FKBP12.6 deficiency in mice facilitates the inducibility of atrial fibrillation.</a> Heart Rhythm. 5 (7), 1047-1047 (2008).</li><li>Gardin, J. M., Siri, F. M., Kitsis, R. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Echocardiographic+assessment+of+left+ventricular+mass+and+systolic+function+in+mice.">Echocardiographic assessment of left ventricular mass and systolic function in mice.</a> Circ Res. 76 (5), 907-907 (1995).</li><li>Tanaka, N., Dalton, N., Mao, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transthoracic+echocardiography+in+models+of+cardiac+disease+in+the+mouse.">Transthoracic echocardiography in models of cardiac disease in the mouse.</a> Circulation. 94 (5), 1109-1109 (1996).</li><li>Patten, R. D., Aronovitz, M. J., Bridgman, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+pulse+wave+and+color+flow+Doppler+echocardiography+in+mouse+models+of+human+disease.">Use of pulse wave and color flow Doppler echocardiography in mouse models of human disease.</a> J Am Soc Echocardiogr. 15 (7), 708-708 (2002).</li><li>Garcia-Fernandez, M. A., Azevedo, J., Moreno, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regional+Left+Ventricular+Diastolic+Dysfunction+Evaluated+by+Pulsed-Tissue+Doppler+Echocardiography.">Regional Left Ventricular Diastolic Dysfunction Evaluated by Pulsed-Tissue Doppler Echocardiography.</a> Echocardiography. 16 (5), 491-491 (1999).</li><li>Pacher, P., Nagayama, T., Mukhopadhyay, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+cardiac+function+using+pressure-volume+conductance+catheter+technique+in+mice+and+rats.">Measurement of cardiac function using pressure-volume conductance catheter technique in mice and rats.</a> Nat Protoc. 3 (9), 1422-1422 (2008).</li><li>Larsen, T. S., Belke, D. D., Sas, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Pflugers Arch. 437 (6), 979-979 (1999).</li><li>Roth, D. M., Swaney, J. S., Dalton, N. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+anesthesia+on+cardiac+function+during+echocardiography+in+mice.">Impact of anesthesia on cardiac function during echocardiography in mice.</a> Am J Physiol Heart Circ Physiol. 282 (6), H2134-H2134 (2002).</li></ol>

Es importante normalizar el nivel de anestesia, 10 la temperatura corporal y la frecuencia cardíaca en una cohorte de ratones para facilitar la comparación entre los diferentes grupos o genotipos de los ratones cuando se utiliza en modo M ecocardiografía. Para la evaluación de personas con discapacidad de la función diastólica, frecuencia cardíaca debe ser reducido con el fin de evaluar las propiedades diastólicas del corazón murino. Las funciones vitales de los animales deben ser observados cuidadosamente con el fin de evitar el fracaso hemodinámico y muerte. Por otro lado, para las mediciones de la función sistólica mediante ecocardiografía M-modelo, la frecuencia cardíaca por debajo de 400 latidos por minuto puede causar diámetros diastólicos a aumentar debido al aumento de llenado del ventrículo izquierdo.

* El software requerido es un software de Vevo, incluyendo la aplicación en modo B, Doppler de onda de pulso de aplicación, y el paquete de herramientas de análisis cardiovascular.

transthoracic echocardiography in mice

En los últimos años, los modelos murinos se han convertido en el principal camino para estudiar los mecanismos moleculares de la disfunción cardíaca como resultado de cambios en la expresión génica. Transgénicos y los métodos de selección de genes puede ser utilizado para generar ratones alterados con el tamaño y la función cardiaca,<sup&gt; 3.1</sup&gt; Y, en consecuencia,<em&gt; In vivo</emTécnicas&gt; se necesitan para evaluar su fenotipo cardíaco. Ecocardiografía transtorácica, la onda de pulso Doppler (PCD) y Doppler tisular (TDI) se puede utilizar para proporcionar mediciones dimensionales del corazón del ratón y para cuantificar el grado de la presión sistólica y el rendimiento cardiaco diastólico. Imágenes de dos dimensiones se utiliza para detectar anomalías anatómicas o movimientos del ventrículo izquierdo, mientras que el eco en modo M se utiliza para la cuantificación de las dimensiones cardíacas y de la contractilidad.<sup&gt; 4,5</sup&gt; Además, personas con discapacidad se utiliza para cuantificar la velocidad localizados del flujo turbulento,<sup&gt; 6</sup&gt; Mientras que TDI se utiliza para medir la velocidad de movimiento del miocardio.<sup&gt; 7</sup&gt; Por lo tanto, la ecocardiografía transtorácica ofrece un método completo para la evaluación no invasiva de la función cardiaca en ratones.

Watch this Scientific Journal Video about Transthoracic Echocardiography in Mice at JoVE.com

Transthoracic Echocardiography in Mice

La ecocardiografía transtorácica ofrece un método no invasivo para la evaluación de la función cardiaca en ratones. Una combinación de ultrasonido y las modalidades de Doppler puede ser usado para obtener mediciones dimensionales del corazón y el flujo sanguíneo intracardíaco, que en conjunto proporcionan una evaluación de la presión sistólica y el rendimiento cardiaco diastólico.

Ecocardiografía transtorácica en ratones

In recent years, murine models have become the primary avenue for studying the molecular mechanisms of cardiac dysfunction resulting from changes in gene ...

Research

JoVE Journal

Medicine

61.1K vistas.  Baylor College of Medicine (BCM). La ecocardiografía transtorácica ofrece un método no invasivo para la evaluación de la función cardiaca en ratones. Una combinación de ultrasonido y las modalidades de Doppler puede ser usado para obtener mediciones dimensionales del corazón y el flujo sanguíneo intracardíaco, que en conjunto proporcionan una evaluación de la presión sistólica y el rendimiento cardiaco diastólico.

Video: Transthoracic Echocardiography in Mice

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.

Ecocardiografía murino y la ecografía

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

Investigación

Medicina

Murine Fetal Echocardiography

Transgenic mice displaying abnormalities in cardiac development and function represent a powerful tool for the understanding the molecular mechanisms underlying both normal cardiovascular function and the pathophysiological basis of human cardiovascular disease. Fetal and perinatal death is a common feature when studying genetic alterations affecting cardiac development 1-3. In order to study the role of genetic or pharmacologic alterations in the early development of cardiac function, ultrasound imaging of the live fetus has become an important tool for early recognition of abnormalities and longitudinal follow-up. Noninvasive ultrasound imaging is an ideal method for detecting and studying congenital malformations and the impact on cardiac function prior to death 4. It allows early recognition of abnormalities in the living fetus and the progression of disease can be followed in utero with longitudinal studies 5,6. Until recently, imaging of fetal mouse hearts frequently involved invasive methods. The fetus had to be sacrificed to perform magnetic resonance microscopy and electron microscopy or surgically delivered for transillumination microscopy. An application of high-frequency probes with conventional 2-D and pulsed-wave Doppler imaging has been shown to provide measurements of cardiac contraction and heart rates during embryonic development with databases of normal developmental changes now available 6-10. M-mode imaging further provides important functional data, although, the proper imaging planes are often difficult to obtain. High-frequency ultrasound imaging of the fetus has improved 2-D resolution and can provide excellent information on the early development of cardiac structures 11.

Fetal and perinatal death is a common feature when studying genetic alterations affecting cardiac development. High-frequency ultrasound imaging has improved 2-D resolution and can provide excellent information on early cardiac development and is an ideal method to detect the impact on cardiac structure and function prior to death.

La ecocardiografía fetal murino

Transgenic mice displaying abnormalities in  cardiac development and function represent a powerful tool for the understanding  the molecular mechanisms ...

In utero Measurement of Heart Rate in Mouse by Noninvasive M-mode Echocardiography

Congenital heart disease (CHD) is the most frequent noninfectious cause of death at birth. The incidence of CHD ranges from 4 to 50/1,000 births (Disease and injury regional estimates, World Health Organization, 2004). Surgeries that often compromise the quality of life are required to correct heart defects, reminding us of the importance of finding the causes of CHD. Mutant mouse models and live imaging technology have become essential tools to study the etiology of this disease. Although advanced methods allow live imaging of abnormal hearts in embryos, the physiological and hemodynamic states of the latter are often compromised due to surgical and/or lengthy procedures. Noninvasive ultrasound imaging, however, can be used without surgically exposing the embryos, thereby maintaining their physiology. Herein, we use simple M-mode ultrasound to assess heart rates of embryos at E18.5 in utero. The detection of abnormal heart rates is indeed a good indicator of dysfunction of the heart and thus constitutes a first step in the identification of developmental defects that may lead to heart failure.

In utero Measurement of Heart Rate in Mouse by Noninvasive M-mode Echocardiography

Ultra-high frequency ultrasound is a powerful live imaging tool to examine cardiac abnormalities in small animals. Its noninvasiveness allows maintaining the physiologic state of embryos. Herein, we show the use of M-mode ultrasound to measure the heart rates of embryos at E18.5 in utero.

En el útero de medición de la frecuencia cardíaca en el ratón por no invasiva Ecocardiografía en modo M

Congenital heart disease (CHD) is the most frequent noninfectious cause of death at birth. The incidence of CHD ranges from 4 to 50/1,000 births (Disease ...

Assessment of Right Ventricular Structure and Function in Mouse Model of Pulmonary Artery Constriction by Transthoracic Echocardiography

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, the RV is significantly affected in pulmonary diseases such as pulmonary artery hypertension (PAH). In addition, the RV is remarkably sensitive to cardiac pathologies, including left ventricular (LV) dysfunction, valvular disease or RV infarction4. To understand the role of RV in the pathogenesis of cardiac diseases, a reliable and noninvasive method to access the RV structurally and functionally is essential.
A noninvasive trans-thoracic echocardiography (TTE) based methodology was established and validated for monitoring dynamic changes in RV structure and function in adult mice. To impose RV stress, we employed a surgical model of pulmonary artery constriction (PAC) and measured the RV response over a 7-day period using a high-frequency ultrasound microimaging system. Sham operated mice were used as controls. Images were acquired in lightly anesthetized mice at baseline (before surgery), day 0 (immediately post-surgery), day 3, and day 7 (post-surgery). Data was analyzed offline using software.
Several acoustic windows (B, M, and Color Doppler modes), which can be consistently obtained in mice, allowed for reliable and reproducible measurement of RV structure (including RV wall thickness, end-diastolic&#160;and end-systolic dimensions), and function (fractional area change, fractional shortening, PA peak velocity, and peak pressure gradient) in normal mice and following PAC.
Using this method, the pressure-gradient resulting from PAC was accurately measured in real-time using Color Doppler mode and was comparable to direct pressure measurements performed with a Millar high-fidelity microtip catheter. Taken together, these data demonstrate that RV measurements obtained from various complimentary views using echocardiography are reliable, reproducible and can provide insights regarding RV structure and function. This method will enable a better understanding of the role of RV cardiac dysfunction.

Right ventricle (RV) dysfunction is critical to the pathogenesis of cardiovascular disease, yet limited methodologies are available for its evaluation. Recent advances in ultrasound imaging provide a noninvasive and accurate option for longitudinal RV study. Herein, we detail a step-by-step echocardiographic method using a murine model of RV pressure overload.

Evaluación del ventrículo derecho Estructura y función en modelo de ratón de la constricción de la arteria pulmonar mediante ecocardiografía transtorácica

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, ...

Ultrasound-guided Transthoracic Intramyocardial Injection in Mice

Murine models of cardiovascular disease are important for investigating pathophysiological mechanisms and exploring potential regenerative therapies. Experiments involving myocardial injection are currently performed by direct surgical access through a thoracotomy. While convenient when performed at the time of another experimental manipulation such as coronary artery ligation, the need for an invasive procedure for intramyocardial delivery limits potential experimental designs. With ever improving ultrasound resolution and advanced noninvasive imaging modalities, it is now feasible to routinely perform ultrasound-guided, percutaneous intramyocardial injection. This modality efficiently and reliably delivers agents to a targeted region of myocardium. Advantages of this technique include the avoidance of surgical morbidity, the facility to target regions of myocardium selectively under ultrasound guidance, and the opportunity to deliver injectate to the myocardium at multiple, predetermined time intervals. With practiced technique, complications from intramyocardial injection are rare, and mice quickly return to normal activity on recovery from anesthetic. Following the steps outlined in this protocol, the operator with basic echocardiography experience can quickly become competent in this versatile, minimally invasive technique.

Echocardiography-guided percutaneous intramyocardial injection represents an efficient, reliable, and targetable modality for the delivery of gene transfer agents or cells into the murine heart. Following the steps outlined in this protocol, the operator can quickly become competent in this versatile, minimally invasive technique.

Guiada por ecografía transtorácica intramiocárdica inyección en ratones

Murine models of cardiovascular disease are important for investigating pathophysiological mechanisms and exploring potential regenerative therapies. ...

Transthoracic Speckle Tracking Echocardiography for the Quantitative Assessment of Left Ventricular Myocardial Deformation

The value of conventional echocardiography is limited by differences in inter-individual image interpretation and therefore largely dependent on the examiners&#39; expertise. Speckle tracking Echocardiography (STE) is a promising but technically challenging method that can be used to quantitatively assess regional and global systolic and diastolic myocardial performance. Myocardial strain and strain rate can be measured in all three dimensions&#160;&#8212; radial, circumferential, longitudinal &#8212; of myocardial deformation. Standard cross-sectional two-dimensional B-mode images are recorded and subsequently postprocessed by automated continuous frame-by-frame tracking and motion analysis of speckles within the myocardium. Images are recorded as digital loops and synchronized to a 3-lead EKG for timing purposes. Longitudinal deformation is assessed in the apical 4-, 3-, and 2-chamber views. Circumferential and radial deformation are measured in the parasternal short axis plane.
Optimal image quality and accurate tissue tracking are paramount for the correct determination of myocardial performance parameters. Utilizing transthoracic STE in a healthy volunteer, the present article is a detailed outline of the essential steps and potential pitfalls of quantitative echocardiographic myocardial deformation analysis.

Speckle tracking echocardiography is an emerging diagnostic imaging technique for the quantitative assessment of global and regional myocardial performance. Standard view echocardiographic motion images are recorded and deformation parameters are subsequently measured by automated continuous frame-by-frame tracking and motion analysis of speckles within the B-mode images of the myocardium.

Transtorácica Ecocardiografía moteado de seguimiento para la evaluación cuantitativa de la deformación miocárdica ventricular izquierda

The value of conventional echocardiography is limited by differences in inter-individual image interpretation and therefore largely dependent on the ...

2D and 3D Echocardiography in the Axolotl (Ambystoma Mexicanum)

Cardiac malfunction as a result of ischemic heart disease is a major challenge, and regenerative therapies to the heart are in high demand. A few model species such as zebrafish and salamanders that are capable of intrinsic heart regeneration hold promise for future regenerative therapies for human patients. To evaluate the outcome of cardioregenerative experiments it is imperative that heart function can be monitored. The axolotl salamander (A. mexicanum) represents a well-established model species in regenerative biology attaining sizes that allows for evaluation of cardiac function. The purpose of this protocol is to establish methods to reproducibly measure cardiac function in the axolotl using echocardiography. The application of different anesthetics (benzocaine, MS-222, and propofol) is demonstrated, and the acquisition of two-dimensional (2D) echocardiographic data in both anesthetized and unanesthetized axolotls is described. 2D echocardiography of the three-dimensional (3D) heart can suffer from imprecision and subjectivity of measurements, and to alleviate this phenomenon a solid method, namely intra/inter-operator/observer analysis, to measure and minimize this bias is demonstrated. Finally, a method to acquire 3D echocardiographic data of the beating axolotl heart at a very high spatiotemporal resolution and with pronounced blood-to-tissue contrast is described. Overall, this protocol should provide the necessary methods to evaluate cardiac function and model anatomy, and flow dynamics in the axolotl using ultrasound imaging with applications in both regenerative biology and general physiological experiments.

2D and 3D Echocardiography in the Axolotl Ambystoma Mexicanum

Here we present echocardiography protocols for two-dimensional and three-dimensional image acquisition of the beating heart of the axolotl salamander (Ambystoma mexicanum), a model species in heart regeneration. These methods allow for longitudinal evaluation of cardiac function at a high spatiotemporal resolution.

Ecocardiografía 2D y 3D en el ajolote (Ambystoma Mexicanum)

Cardiac malfunction as a result of ischemic heart disease is a major challenge, and regenerative therapies to the heart are in high demand. A few model ...

Electromagnetic Navigation Transthoracic Nodule Localization for Minimally Invasive Thoracic Surgery

The increased use of chest computed tomography (CT) has led to an increased detection of pulmonary nodules requiring diagnostic evaluation and/or excision. Many of these nodules are identified and excised via minimally invasive thoracic surgery; however, subcentimeter and subsolid nodules are frequently difficult to identify intra-operatively. This can be mitigated by the use of electromagnetic transthoracic needle localization. This protocol delineates the step-by-step process of electromagnetic localization from the pre-operative period to the postoperative period and is an adaptation of the electromagnetically guided percutaneous biopsy previously described by Arias et al. Pre-operative steps include obtaining a same day CT followed by the generation of a three-dimensional virtual map of the lung. From this map, the target lesion(s) and an entry site are chosen. In the operating room, the virtual reconstruction of the lung is then calibrated with the patient and the electromagnetic navigation platform. The patient is then sedated, intubated, and placed in the lateral decubitus position. Using a sterile technique and visualization from multiple views, the needle is inserted into the chest wall at the prechosen skin entry site and driven down to the target lesion. Dye is then injected into the lesion and, then, continuously during needle withdrawal, creating a tract for visualization intra-operatively. This method has many potential benefits when compared to the CT-guided localization, including a decreased radiation exposure and decreased time between the dye injection and the surgery. Dye diffusion from the pathway occurs over time, thereby limiting intra-operative nodule identification. By decreasing the time to surgery, there is a decrease in wait time for the patient, and less time for dye diffusion to occur, resulting in an improvement in nodule localization. When compared to electromagnetic bronchoscopy, airway architecture is no longer a limitation as the target nodule is accessed via a transparenchymal approach. Details of this procedure are described in a step-by-step fashion.

Presented here is a protocol for lung nodule localization using dye marking via electromagnetically navigated transthoracic needle access. The technique described here can be accomplished in the peri-operative period to optimize nodule localization and to successful resection when performing minimally invasive thoracic surgery.

Localización de nódulos transtorácicos de navegación electromagnética para cirugía torácica mínimamente invasiva

The increased use of chest computed tomography (CT) has led to an increased detection of pulmonary nodules requiring diagnostic evaluation and/or ...

Transthoracic Echocardiographic Examination in the Rabbit Model

Large animal models such as the rabbit are valuable for translational preclinical research. Rabbits have a similar cardiac electrophysiology compared to that of humans and that of other large animal models such as dogs and pigs. However, the rabbit model has the additional advantage of lower maintenance costs compared to other large animal models. The longitudinal evaluation of cardiac function using echocardiography, when appropriately implemented, is a useful methodology for preclinical assessment of novel therapies for heart failure with reduced ejection fraction (e.g. cardiac regeneration). The correct use of this non-invasive tool requires the implementation of a standardized examination protocol following international guidelines. Here we describe, step by step, a detailed protocol supervised by veterinary cardiologists for performing echocardiography in the rabbit model, and demonstrate how to correctly obtain the different echocardiographic views and imaging planes, as well as the different imaging modes available in a clinical echocardiography system routinely used in human and veterinary patients.

Here we describe, step by step, a detailed protocol for performing echocardiography in the rabbit model. We show how to correctly obtain the different echocardiographic views and imaging planes, as well as the different imaging modes available in a clinical echocardiography system routinely used in human and veterinary patients.

Examen Ecocardiográfico Transtorácico en el Modelo Conejo

Large animal models such as the rabbit are valuable for translational preclinical research. Rabbits have a similar cardiac electrophysiology compared to ...

Transthoracic Echocardiography to Assess Post-Resuscitation Left Ventricular Dysfunction After Acute Myocardial Infarction and Cardiac Arrest in Pigs

One of the main causes of out-of-hospital cardiac arrest is acute myocardial infarction (AMI). After successful resuscitation from cardiac arrest, approximately 70% of patients die before hospital discharge due to post-resuscitation myocardial and cerebral dysfunction. In experimental models, myocardial dysfunction after cardiac arrest, characterized by an impairment in both left ventricular (LV) systolic and diastolic function, has been described as reversible but very little data are available in cardiac arrest models associated with AMI in pigs. Transthoracic echocardiography is the first-line diagnostic test for the assessment of myocardial dysfunction, structural changes and/or AMI extension. In this pig model of ischemic cardiac arrest, echocardiography was done at baseline and 2-4 and 96 hours after resuscitation. In the acute phase, the examinations are done in anesthetized, mechanically ventilated pigs (weight 39.8 &#177; 0.6 kg) and ECG is recorded continuously. Mono- and bi-dimensional, Doppler and tissue Doppler recordings are acquired. Aortic and left atrium diameter, end-systolic and end-diastolic left ventricular wall thicknesses, end-diastolic and end-systolic diameters and shortening fraction (SF) are measured. Apical 2-, 3-, 4-, and 5-chamber views are acquired, LV volumes and ejection fraction are calculated. Segmental wall motion analysis is done to detect the localization and estimate the extent of myocardial infarction. Pulsed Wave Doppler echocardiography is used to record trans-mitral flow velocities from a 4-apical chamber view and trans-aortic flow from a 5-chamber view to calculate LV cardiac output (CO) and stroke volume (SV). Tissue Doppler Imaging (TDI) of LV lateral and septal mitral anulus is recorded (TDI septal and lateral s&#39;, e&#39;, a&#39; velocities). All the recordings and measurements are done according to the recommendations of the American and European Societies of Echocardiography Guidelines.

Transthoracic echocardiography is the first-line diagnostic test for post-resuscitation left ventricular dysfunction and structural changes in a pig model of cardiac arrest.

Ecocardiografía transtorácica para evaluar la disfunción ventricular izquierda posterior a la reanimación después del infarto agudo de miocardio y el paro cardíaco en cerdos