The study was funded by the Ludwig Boltzmann Institute for Lung Vascular Research.

The study was performed according to national regulations for animal experimentation and EU Directive 2010/63. Prepare equipment as described previously by Brittain&#160;et al.8.
1. Mouse Preparation
<ol>
	<li>Obtain 12&#160;to 13 week-old male C57Bl6/J mice and house them with a 12 h light/dark cycle, at a constant room temperature, and with ad libitum access to standard laboratory chow and water, until the start of the experiment.</li>
	<li>Anesthetize the ...

<ol>
	<li>Egemnazarov, B., Crnkovic, S., Nagy, B. M., Olschewski, H., Kwapiszewska, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Right+ventricular+fibrosis+and+dysfunction:+Actual+concepts+and+common+misconceptions.">Right ventricular fibrosis and dysfunction: Actual concepts and common misconceptions.</a> Matrix Biology: Journal of the International Society for Matrix Biology. 68-69, 507-521 (2018).</li><li>Rain, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Right+ventricular+diastolic+impairment+in+patients+with+pulmonary+arterial+hypertension.">Right ventricular diastolic impairment in patients with pulmonary arterial hypertension.</a> Circulation. 128, 1-10 (2013).</li><li>Egemnazarov, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pressure+overload+creates+right+ventricular+diastolic+dysfunction+in+a+mouse+model:+assessment+by+echocardiography.">Pressure overload creates right ventricular diastolic dysfunction in a mouse model: assessment by echocardiography.</a> Journal of the American Society of Echocardiography. 28, 828-843 (2015).</li><li>Crnkovic, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+and+molecular+factors+associated+with+TAPSE+in+hypoxic+pulmonary+hypertension.">Functional and molecular factors associated with TAPSE in hypoxic pulmonary hypertension.</a> American Journal of Physiology. Lung Cellular and Molecular Physiology. 311, 59-73 (2016).</li><li>Shi, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=miR-223-IGF-IR+signalling+in+hypoxia-+and+load-induced+right-ventricular+failure:+a+novel+therapeutic+approach.">miR-223-IGF-IR signalling in hypoxia- and load-induced right-ventricular failure: a novel therapeutic approach.</a> Cardiovascular Research. 111, 184-193 (2016).</li><li>de Raaf, M. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tyrosine+kinase+inhibitor+BIBF1000+does+not+hamper+right+ventricular+pressure+adaptation+in+rats.">Tyrosine kinase inhibitor BIBF1000 does not hamper right ventricular pressure adaptation in rats.</a> American Journal of Physiology - Heart and Circulatory Physiology. 311, 604-612 (2016).</li><li>Zhou, Y. Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comprehensive+transthoracic+cardiac+imaging+in+mice+using+ultrasound+biomicroscopy+with+anatomical+confirmation+by+magnetic+resonance+imaging.">Comprehensive transthoracic cardiac imaging in mice using ultrasound biomicroscopy with anatomical confirmation by magnetic resonance imaging.</a> Physiological Genomics. 18, 232-244 (2004).</li><li>Brittain, E., Penner, N. L., West, J., Hemnes, A. <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+the+right+heart+in+mice.">Echocardiographic assessment of the right heart in mice.</a> Journal of Visualized Experiments. (81), e50912 (2013).</li><li>Kitchen, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonparametric+vs+parametric+tests+of+location+in+biomedical+research.">Nonparametric vs parametric tests of location in biomedical research.</a> American Journal of Ophthalmology. 147, 571-572 (2009).</li><li>Yan, F., Robert, M., Li, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Statistical+methods+and+common+problems+in+medical+or+biomedical+science+research.">Statistical methods and common problems in medical or biomedical science research.</a> International Journal of Physiology, Pathophysiology and Pharmacology. 9, 157-163 (2017).</li><li>Guihaire, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Non-invasive+indices+of+right+ventricular+function+are+markers+of+ventricular-arterial+coupling+rather+than+ventricular+contractility:+insights+from+a+porcine+model+of+chronic+pressure+overload.">Non-invasive indices of right ventricular function are markers of ventricular-arterial coupling rather than ventricular contractility: insights from a porcine model of chronic pressure overload.</a> European Heart Journal Cardiovascular Imaging. 14, 1140-1149 (2013).</li><li>Sareen, N., Ananthasubramaniam, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strain+Imaging:+From+Physiology+to+Practical+Applications+in+Daily+Practice.">Strain Imaging: From Physiology to Practical Applications in Daily Practice.</a> Cardiology in Review. 24, 56-69 (2016).</li><li>Thavendiranathan, P., et al. <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+myocardial+strain+imaging+by+echocardiography+for+the+early+detection+of+cardiotoxicity+in+patients+during+and+after+cancer+chemotherapy:+a+systematic+review.">Use of myocardial strain imaging by echocardiography for the early detection of cardiotoxicity in patients during and after cancer chemotherapy: a systematic review.</a> Journal of the American College of Cardiology. 63, 2751-2768 (2014).</li><li>Sengelov, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Global+Longitudinal+Strain+Is+a+Superior+Predictor+of+All-Cause+Mortality+in+Heart+Failure+With+Reduced+Ejection+Fraction.">Global Longitudinal Strain Is a Superior Predictor of All-Cause Mortality in Heart Failure With Reduced Ejection Fraction.</a> JACC: Cardiovascular Imaging. 8, 1351-1359 (2015).</li><li>Silvani, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physiological+Mechanisms+Mediating+the+Coupling+between+Heart+Period+and+Arterial+Pressure+in+Response+to+Postural+Changes+in+Humans.">Physiological Mechanisms Mediating the Coupling between Heart Period and Arterial Pressure in Response to Postural Changes in Humans.</a> Frontiers in Physiology. 8, 163 (2017).</li><li>Mohan, M., Anandh, B., Thombre, D. 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The echocardiographic RV function and dimension assessment from parasternal positions have been well described. In contrast, the apical position in mouse echocardiography has been neglected partly due to technical difficulties. Using a horizontal platform position, it is difficult to obtain a sufficient acoustic window for four-chamber view imaging. To facilitate the imaging of this position, the platform can be tilted to the left, a manipulation similar to the left-sided positioning of patients. This should result in a ...

Diastolic dysfunction is a prominent feature of right ventricular (RV) remodeling1 and is associated with pressure-overload conditions2. Echocardiography (EchoCG) can be used for the characterization of RV diastolic dysfunction3,4. Despite recent developments in small animal echocardiography, measurements of diastolic parameters are rarely reported. In contrast, measurements of the systolic function are widely used for the characterization of transgenic mice5, as well as for the evaluation of a treatment response6.
This can be partly explained by the difficulties in the measurement of diastolic parameters from the apical four-chamber view. Visualization of the heart in this position can be facilitated by tilting the fixation platform LeCa or RiCr. Even if these manipulations are used, echocardiographers do not report them in their manuscripts4,7. Therefore, it remains unclear whether these manipulations provide comparable results. Moreover, this also precludes a development of standardized nomenclature of this position for mice.
The aim of this study was to describe two positions for apical four-chamber view visualization and compare their results. To determine the differences between the two positions, we have utilized the mouse pulmonary artery banding (PAB) model, in which a tantalum clip leads to a partial occlusion of the pulmonary artery. This occlusion results in right ventricle remodeling and dysfunction. Full details of the PAB operation can be found in previously published work3. Sham-operated mice, where the clip was placed next to the pulmonary artery, were used for comparison. EchoCG investigations were performed three weeks post-operation using the imaging system with a 30 MHz scan head (see Table of Materials for both). Nomenclature for the description of the positions and orientations between the mouse and the ultrasound beam is used as described by Zhou et al.7.

<table border="0" cellpadding="0" cellspacing="0" style="width:839px;" width="838">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="40">
			<td height="40" style="height:40px;width:244px;">RMV-707B scan head 30 MHz</td>
			<td style="width:189px;">Visual Sonics</td>
			<td style="width:239px;">P/N 11459</td>
			<td style="width:167px;">mouse scan head</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">VisualSonics Vevo 770&#174; High-Resolution Imaging System</td>
			<td>Visual Sonics</td>
			<td>770-230</td>
			<td>ultrasound machine</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Veet depilation creme for sensitive skin</td>
			<td>Veet</td>
			<td>07768307&#160;</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Surgical tape Durapore 3M</td>
			<td>3M Deutschland GmbH</td>
			<td>1538-1</td>
			<td>for fixation</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Askina Brauncel cellulose swabs</td>
			<td>B.Braun</td>
			<td>9051015</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Aquasonic ultrasound gel</td>
			<td>Parker Laboratories Inc.</td>
			<td>BT025-0037L</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Electrode Gel</td>
			<td>GE medical systems information technologies Inc.</td>
			<td>2034731-002</td>
			<td>apply to extremities for countinous ECG and heart rate monitoring</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Thermasonic gel warmer</td>
			<td>Parker Laboratories Inc.</td>
			<td>82-04-20</td>
			<td>to reduce heat loss warm up the ultrasound gel before use</td>
		</tr>
	</tbody>
</table>

echocardiographic measurement of right ventricular diastolic parameters in mouse

Diastolic dysfunction is a prominent feature of right ventricular (RV) remodeling associated with conditions of pressure overload. However, the RV diastolic function is rarely quantified in experimental studies. This might be due to technical difficulties in the visualization of the RV in the apical four-chamber view in rodents. Here we describe two positions facilitating the visualization of the apical four-chamber view in mice to assess the RV diastolic function.
The apical four-chamber view is enabled by tilting the mouse fixation platform to the left and caudally (LeCa) or to the right and cranially (RiCr). Both positions provide images of comparable quality. The results of the RV diastolic function obtained from two positions are not significantly different. Both positions are comparably easy to perform. This protocol can be incorporated into published protocols and enables detailed investigations of the RV function.

The apical four-chamber view is difficult to obtain in mice. Therefore, manipulations of the platform position can help to visualize the heart by changing its position in the thorax. The tilting of the platform to the left and to the right improved the acoustic window and provided images of comparable quality in B-mode (Figure 1). After obtaining the correct positions, measurements in PW-, M-, and TDI-modes provided images of comparable quality (<strong class...

Watch this Scientific Journal Video about Echocardiographic Measurement of Right Ventricular Diastolic Parameters in Mouse at JoVE.com

Echocardiographic Measurement of Right Ventricular Diastolic Parameters in Mouse

Here we describe and compare two positions for obtaining the apical four-chamber view in mice. These positions enable the quantification of the right ventricular function, provide comparable results, and can be used interchangeably.

Diastolic dysfunction is a prominent feature of right ventricular (RV) remodeling associated with conditions of pressure overload. However, the RV ...

Usually visualization of the apical four chamber view is possible only in 65 to 70%of investigated mice. The main advantage of this technique is that the combined usage of both tilting positions enables that requisition in almost all investigated mice. After the mouse has reached the appropriate level of light sedation, fix the mouse on a heated platform and apply electrode gel to the extremities for continuous monitoring of the heart rate and temperature.Remove the chest hair with depilatory cream and apply a layer of ultrasound coupling gel to the tip of the transducer. For an apical four chamber view with the left and caudal platform tilt, angle the platform 10 to 15 degrees to the left and 10 to 15 degrees caudally. Position the transducer above the apex within the imaging plane, 45 degrees to the coronal plane with the central axis of the ultrasound beam directed cranially posteriorly and to the left.Press the B-mode button to activate the B-mode to de-imaging and locate the left ventricul, left atrium, right ventricle, right atrium, mitral valve and tricuspid valve on the acoustic window. To ensure that you are in the right position slide the transducer up and down along the coronal plane. Manipulate the imagine plane in the coronal plane and rotate clock and counter clockwise around the central axis until both ventricles are visualized at their longest dimension, and both atria are visible to obtain the four chamber view.Press cine store to save the recording. Then press scan freeze to pause the system. To measure the transtricuspid blood flow velocity press scan freeze to activate the system and press overlay several times to activate the sample volume for the post wave mode.With the four chamber imaging view use the track ball to position the sample volume at the opening of the tricuspid valves and click pulse wave mode to measure the inflow velocities. Click cine store to save the optimized recording followed by scan freeze to pause the system. For measurement of the tricuspid annular plane systolic excursion, click scan freeze to activate the system and switch to B-mode.Some manipulations of the image might be necessary to regain the correct four chamber view. Click overlay several times to activate the sample volume of the M-mode and use the trackball to align the sample volume with the lateral part of the tricuspid annulus. Use the trackball to pull the edges of the sample volume until the entire amplitude of the cardiac movement during the cardiac cycle is covered.And activate the M-mode. The tricuspid annulus movements should appear as a wave, then click cine store to save the recording and scan freeze to pause the system. For measurement of the tissue doppler parameters activate the system and the B-mode.Click overlay several times to activate the sample volume for tissue doppler imaging and use the trackball to align the sample volume with the lateral part of the tricuspid annulus, such that the right ventricle free wall creates an angle with the tricuspid valve. Pull the edges of the sample to adjust the sample volume to include the systolic and diastolic extreme positions of the annulus, and click tissue to activate the tissue doppler imaging mode. Then click cine store to save the recording and scan freeze to pause the system.Tilting the platform to the left and to the right improves the acoustic window and provides images of comparable quality in healthy and diseased mouse hearts in the B-mode. After obtaining the correct positions, measurements in the M-mode, tissue doppler imaging mode and pulsed wave mode provide images of comparable quality with similar diastolic parameter results obtained in either the right cranial or left caudal platform positions in both healthy and diseased hearts. Further, correlation analysis reveals a good agreement between the values obtained from these two facilitated positions.While attempting this procedure it's important to remember that echocardiography is a non-invasive technique for the evaluation of the cardiac function. Following this procedure, tissue samples can be collected after the physiological measurements to answer additional questions about the morphologic substrate or molecular mechanisms of cardiac dysfunction. This technique has paved the way for the researchers in the field of pulmonary hypertension to explore the mechanisms of the right ventricle adaptation to pressure overload using mouse models of pulmonary hypertension.To obtain the producible results between experiments, tightly control the physiological parameters of the animal such as heart rate and body temperature and maintain the level of anesthesia as superficial as possible to minimize influencing cardiac function.

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7.3K vistas.  Ludwig Boltzmann Institute for Lung Vascular Research. Por lo general, la visualización de la vista apical de cuatro cámaras sólo es posible en 65 a 70% de los ratones investigados. La principal ventaja de esta técnica es que el uso combinado de ambas posiciones de inclinación permite esa solicitud en casi todos los ratones investigados. Después de que el ratón haya alcanzado el nivel adecuado de sedación de luz, fije el ratón en una plataforma calentada y aplique gel de electrodo a las extremidades para la monitorización continua de la...