Nous tenons à remercier le Dr Corey Reynolds et le Core BCM phénotypage de souris pour leur aide d&#39;experts à ce projet et l&#39;accès aux installations type. XHTW est un WM Keck Foundation Distinguished Scholar jeunes en recherche médicale, et est également soutenu par le NIH / NHLBI subventions R01 et R01-HL089598-HL091947 et Muscular Dystrophy Association subvention no 69238. Ce travail est également soutenu en partie par la Fondation Leducq l&#39;Alliance pour la CaMKII Signalisation Cœur.

1. Souris prépare à des études d&#39;imagerie <ol><li> Avant les études d&#39;imagerie, anesthésier la souris (2% d&#39;isoflurane mélange avec 0,5 L / min à 100% O 2) dans la chambre de l&#39;induction. Soyez sûr de filtrer des effluents gazeux pour la sécurité de l&#39;opérateur. Retirez les animaux de la chambre de l&#39;induction et l&#39;utilisation tondeuses à raser le poil de l&#39;encolure au niveau de la poitrine mi. Puis enlever les poils du corps qui restent à la crème d&#39;épilation. Cette préparation peut être effectuée un jour avant les études d&#39;imagerie afin de minimiser le potentiel des réactions de stress indésirable chez les souris. </li><li> Appliquer duralube gel pour les deux yeux pour éviter le dessèchement de la sclérotique (éviter tout contact avec la cornée avec l&#39;applicateur de gel). Placez la souris anesthésiés en décubitus dorsal au sommet d&#39;un coussin chauffant intégré avec des dérivations ECG afin de maintenir la température du corps. </li><li> Placer le museau dans un cône de nez connecté au système d&#39;anesthésie à maintenir un niveau de sédation état ​​stable pendant toute la procédure (1,0% à 1,5% d&#39;isoflurane mélange avec 0,5 L / min à 100% O 2). Effectuer un pincement de l&#39;orteil ou la queue pour confirmer la sédation. Si nécessaire, le niveau d&#39;anesthésie peut être ajustée pour obtenir une fréquence cardiaque cible de 450 ± 50 battements par minute (bpm). </li><li> Insérez doucement une sonde rectale (après lubrification) pour surveiller en permanence et ajuster la température du corps via le coussin chauffant. Il est important de maintenir la température du corps dans une fourchette étroite (37,0 ° C ± 0,5 ° C), comme des changements, même modérée de la température et la fréquence cardiaque affectent la fonction cardiaque chez la souris. </li><li> Appliquer le gel d&#39;électrode sur les quatre pattes et collez-les sur les électrodes de l&#39;ECG. </li></ol> 2. Évaluer la fonction systolique du coeur <ol><li> Pour commencer cette procédure, appliquer une couche de gel échographique préchauffé à la poitrine, surtout la zone recouvrant le cœur. Gel doit être réchauffé à la température du corps approximatives. Un volume de gel froid peut rapidement ajouter au taux de perte de température corporelle. Eviter les bulles d&#39;air dans le gel, qui peut interférer avec l&#39;imagerie par ultrasons. </li><li> Immobiliser la souris dans une position légèrement à la hausse (jusqu&#39;à la tête) sous un angle léger. L&#39;utilisation d&#39;un micromanipulateur, immobiliser la sonde d&#39;échographie avec un angle de 90 ° entre la sonde et le cœur. </li><li> Pour commencer à faire des courts-axe mesures échocardiographiques, abaisser la sonde sur le thorax parasternale. Evitez de placer la sonde directement sur le sternum ou sur la peau, car cela va fausser le signal. </li><li> Tout d&#39;abord, nous allons effectuer deux dimensions (2D) d&#39;imagerie («B-mode&quot;) pour obtenir une vue sur l&#39;axe parasternale court. Ajustez la zone de visualisation de la sonde afin d&#39;obtenir une image complète en fonction de la taille du cœur de l&#39;animal. </li><li> Une image correcte dans cette orientation comprendra le ventricule gauche et une partie légère de la paroi ventriculaire droite. La flèche (montré dans la vidéo) indique les muscles antéro-latérale et postéro papillaire, la paroi postérieure et antérieure de la BT, le mur intraventriculaire septale, et une partie légère de la paroi ventriculaire droite. Lors de ces mesures, une attention particulière aux possibilités de mouvement de la paroi des anomalies (par exemple, hypokinésie, akinasia, asynchronisme) ou des anévrismes. </li><li> Ensuite, nous allons utiliser l&#39;échocardiographie en mode M, qui fournit une 1-dimensionnel (1D) de vue, d&#39;obtenir des mesures fines de dimensions cardiaque et la contractilité. Boutique images acquises pour une évaluation ultérieure des paramètres de la fonction systolique ventriculaire gauche. </li></ol> 3. Évaluer la fonction diastolique du coeur <ol><li> Alors que la visualisation de l&#39;axe parasternale bref, nous pouvons effectuer Doppler tissulaire (TDI) à mesurer la vitesse de mouvement du myocarde. La région d&#39;intérêt est marqué pour inclure une paroi ventriculaire gauche à l&#39;évaluation postérieure axe radial. La forme d&#39;onde obtenue aura quatre sommets pour évaluer la fonction diastolique: IVRT, E &#39;, A&#39;, et IVCT. S &#39;représente la vitesse systolique. (Figure 3B) Ces paramètres seront décrits plus loin dans la section des résultats représentatifs. </li><li> Pulse-Doppler (PWD) peut être utilisé pour mesurer la vitesse du flux sanguin dans une petite zone à une profondeur spécifique dans le tissu myocardique. Pour l&#39;image du modèle d&#39;écoulement trans-mitral, l&#39;inclinaison de l&#39;animal vers l&#39;arrière en position de Trendelenburg. Inclinez la sonde vers le haut, telles que la sonde est orthogonale à la pointe du cœur. </li><li> Maintenant augmenter le niveau de l&#39;isoflurane pour abaisser la fréquence cardiaque à 300-350 bpm, ce qui va ralentir le mouvement de la valve mitrale. Pour les études de comparaison, il est important de maintenir le rythme cardiaque similaire entre les animaux. </li><li> Visualisez les mouvements de la valvule mitrale comme point de référence pour mesurer le débit dans la vanne. Placez le volume d&#39;échantillon à l&#39;extrémité de la valve mitrale. </li><li> Mesurer les modèles d&#39;écoulement à travers la valve mitrale à l&#39;aide PWD. Deux vagues sont typiquement vus, l&#39;un représentant le remplissage passif du ventricule (début [E]-ondes), etune compatible avec le remplissage actif avec la systole auriculaire (atrial [A]-ondes). Dans un cœur sain, la vitesse E-onde est légèrement supérieure à celle de l&#39;onde A (figure 3C). </li><li> Une fois que toutes les mesures sont terminées, enlever le gel de l&#39;électrode (par essuyant doucement avec des tampons de gaze standard) et les contraintes de l&#39;animal. Permettre à l&#39;animal effrénée pour récupérer au sommet de la chauffée pad ECG dans une position verticale et éteindre l&#39;anesthésie. Lorsque la souris se réveille, le retourner dans sa cage. </li></ol> 4. Représentant Résultats échocardiographie transthoracique Non invasive des études échocardiographiques peuvent être utilisés pour évaluer la morphologie et la fonction ventriculaire gauche dans les modèles murins de maladies cardiaques 4,5. Cette technique est largement utilisée et offre une alternative aux procédures de terminal pour évaluer la fonction ventriculaire gauche, tels que la pression intracardiaque volume de la boucle measurements.8 ou le modèle ex vivo coeur de travail. 9 Évaluation des dimensions de la chambre par le LV transthoracique échocardiographie en mode M permet la détection de l&#39;élargissement de la chambre anormale BT ou l&#39;épaisseur de paroi accrue dans divers modèles de maladie cardiaque. 5 Ainsi, l&#39;échocardiographie transthoracique, combinée à impulsions Doppler , constitue une avenue complète pour l&#39;évaluation non invasive de la tension systolique et diastolique de la fonction cardiaque chez la souris. <img src="/files/ftp_upload/1738/1738fig1.jpg" alt="Figure 1" /> Figure 1. Vue d&#39;ensemble de Vevo 770 haute résolution in vivo de micro-système d&#39;imagerie pour l&#39;échocardiographie et l&#39;imagerie Doppler. (A) Nous utilisons le système ferroviaire intégré VisualSonics avec l&#39;unité de surveillance physiologique, ECG bord, et RMV 30MHz scan tête. (B) La souris est positionné et correctement de retenue sur le plateau chauffant avec des électrodes ECG intégré (couleur or). Les quatre membres sont enregistrés dans les électrodes ECG. (CD) photographies montrant les angles appropriés pour impulsion-Doppler utilisé pour obtenir des mesures de la fonction diastolique, tel que décrit dans l&#39;article 4 du protocole. Orientation de la sonde pour des mesures de la fonction systolique est montrer dans le protocole vidéo. <img src="/files/ftp_upload/1738/1738fig2.jpg" alt="Figure 2" /> Figure 2. Images représentant échocardiographie 2D (mode B) (A). Para-sternale petit axe vue montrant la face antérieure du ventricule gauche (AW) et postérieur (TP) des murs, le mur intraventriculaire septale (SW), et le mur latéral (LW). Le diamètre de la lumière du ventricule gauche peut être mesuré que le diamètre interne du ventricule gauche (LVID). L&#39;astérisque indique le muscle papillaire postéro. (B) apicale quatre cavités avec une zone de visualisation au cours de la valve mitrale pour la détermination des E / A des vitesses de pointe. Mval, dépliant de la valve mitrale antérieure; MVPL, dépliant de la valve mitrale postérieure; RV, ventricule droit; LV, ventricule gauche. <img src="/files/ftp_upload/1738/1738fig3.jpg" alt="Figure 3" /> Figure 3. Acquisition et quantification des données échocardiographie et doppler. Ce chiffre contient des images représentant des données acquises correspondant aux images échocardiographie 2D présenté dans la Figure 2. (A) en mode M avec le traçage des lignes indiquant en fin de systole (ESD) et de fin de diastole diamètres (EDD). LVAWD / S, à gauche épaisseur de la paroi ventriculaire antérieure (diastole / systole); LVPWD / S, a quitté l&#39;épaisseur des parois ventriculaires postérieures (diastole / systole). (B) tracés Représentant pour Doppler tissulaire de la LV paroi postérieure. IVRT, temps de relaxation isovolumique; IVCT, temps de contraction isovolumique. L&#39;E &#39;onde correspond à la requête de l&#39;anneau mitral diastolique au cours remplissage précoce de la LV, et les A&#39; d&#39;onde provient de la systole auriculaire au cours retard de remplissage de la BT. S &#39;représentent vélocité systolique. (C) Pulse Doppler enregistrement de conseils mitrale valve de valvule mitrale fournit les modèles de vitesse apport à partir de laquelle la vitesse diastolique début (E), la vélocité diastolique fin à la contraction diastolique (A), et le rapport E / A peuvent être dérivées. Le IVRT est aussi une variable utile pour caractériser la fonction diastolique et des pressions de remplissage. HE indique le temps d&#39;éjection.

<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>

Il est important de normaliser le niveau de l&#39;anesthésie, 10 la température du corps, et la fréquence cardiaque au sein d&#39;une cohorte de souris pour faciliter la comparaison entre les différents groupes ou des génotypes de souris lors de l&#39;utilisation en mode M échocardiographie. Pour l&#39;évaluation des personnes handicapées de la fonction diastolique, la fréquence cardiaque doit être abaissé afin d&#39;évaluer les propriétés diastoliques du cœur murin. Les fonctions vitales de l&#39;animal doivent être étroitement surveillés afin d&#39;éviter une défaillance hémodynamique et la mort. D&#39;autre part, pour des mesures en utilisant la fonction systolique du modèle M-taux échocardiographie cardiaque, en dessous de 400 battements par minute peuvent causer fin de diastole diamètres d&#39;augmenter à cause de remplissage accru de la LV.

* Le logiciel requis est un logiciel Vevo, y compris en mode B demande, l&#39;onde de pouls Doppler application, et cardiovasculaires outils d&#39;analyse de l&#39;emballage.

transthoracic echocardiography in mice

Ces dernières années, les modèles murins sont devenus la principale voie pour l&#39;étude des mécanismes moléculaires de la dysfonction cardiaque résultant de changements dans l&#39;expression des gènes. Transgéniques et des méthodes de ciblage génique peut être utilisée pour générer des souris dont la taille et la fonction cardiaque altérée,<sup&gt; 1-3</sup&gt; Et, par conséquent,<em&gt; In vivo</emTechniques&gt; sont nécessaires pour évaluer leur phénotype cardiaque. L&#39;échocardiographie transthoracique, l&#39;onde de pouls Doppler (PWD), et Doppler tissulaire (TDI) peuvent être utilisés pour fournir des mesures dimensionnelles du cœur de souris et de quantifier le degré de pression systolique cardiaque et la fonction diastolique. Imagerie bidimensionnelle est utilisée pour détecter une anomalie anatomique ou des mouvements du ventricule gauche, alors que M-mode écho est utilisé pour la quantification des dimensions cardiaques et la contractilité.<sup&gt; 4,5</sup&gt; En outre, les personnes handicapées est utilisé pour quantifier la vitesse d&#39;écoulement turbulent localisé,<sup&gt; 6</sup&gt; Alors que les TDI est utilisé pour mesurer la vitesse du mouvement du myocarde.<sup&gt; 7</sup&gt; Ainsi, une échocardiographie transthoracique propose une méthode complète pour l&#39;évaluation non invasive de la fonction cardiaque chez la souris.

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

Transthoracic Echocardiography in Mice

L&#39;échocardiographie transthoracique propose une méthode non invasive pour l&#39;évaluation de la fonction cardiaque chez la souris. Une combinaison de l&#39;échographie Doppler et les modalités d&#39;imagerie peuvent être utilisées pour obtenir des mesures dimensionnelles du cœur et la circulation sanguine intracardiaque, qui, ensemble, fournissent une évaluation de la performance cardiaque et systolique diastolique.

L&#39;échocardiographie transthoracique chez la souris

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

61.3K vues.  Baylor College of Medicine (BCM). L'échocardiographie transthoracique propose une méthode non invasive pour l'évaluation de la fonction cardiaque chez la souris. Une combinaison de l'échographie Doppler et les modalités d'imagerie peuvent être utilisées pour obtenir des mesures dimensionnelles du cœur et la circulation sanguine intracardiaque, qui, ensemble, fournissent une évaluation de la performance cardiaque et systolique diastolique.

Vidéo: 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.

L&#39;échocardiographie et l&#39;imagerie par ultrasons murin

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

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Médecine

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.

Murin échocardiographie fœtale

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.

In utero mesure de la fréquence cardiaque chez la souris par M mode non invasive échocardiographie

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.

Évaluation de ventriculaire droite Structure et fonction dans le modèle de souris de l&#39;artère pulmonaire constriction par échocardiographie transthoracique

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.

Guidée par échographie transthoracique intramyocardique injection chez la souris

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.

Transthoracique Speckle Tracking échocardiographie pour l&#39;évaluation quantitative de gauche Ventricular Myocardial Déformation

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.

Échocardiographie 2D et 3D chez l’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 ...

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.

Navigation électromagnétique Localisation des nodules transthoraciques pour la chirurgie thoracique mini-invasive

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 échocardiographique transthoracique dans le modèle lapin

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.

Échocardiographie transthoracique pour évaluer la dysfonction ventriculaire gauche post-réanimation après un infarctus aigu du myocarde et un arrêt cardiaque chez le porc