This work was supported by NHLBI K01 HL155241 and AHA CDA849387 awarded to the author P.C.R.

<ol>
	<li>Galie, N., McLaughlin, V. V., Rubin, L. J., Simonneau, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+overview+of+the+6th+World+Symposium+on+Pulmonary+Hypertension.">An overview of the 6th World Symposium on Pulmonary Hypertension.</a> European Respiratory Journal. 53 (1), 1802148 (2019).</li><li>Tyagi, S., Batra, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+therapeutic+approaches+of+pulmonary+arterial+hypertension.">Novel therapeutic approaches of pulmonary arterial hypertension.</a> International Journal of Angiology. 28 (2), 112-117 (2019).</li><li>Hoeper, M. 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=Targeted+therapy+of+pulmonary+arterial+hypertension:+Updated+recommendations+from+the+Cologne+Consensus+Conference+2018.">Targeted therapy of pulmonary arterial hypertension: Updated recommendations from the Cologne Consensus Conference 2018.</a> International Journal of Cardiology. 272, 37-45 (2018).</li><li>Sommer, N., 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=Current+and+future+treatments+of+pulmonary+arterial+hypertension.">Current and future treatments of pulmonary arterial hypertension.</a> British Journal of Pharmacology. 178 (1), 6-30 (2021).</li><li>Farber, H. 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F., Lucas, M., Cernacek, P., Dupuis, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effectiveness+of+a+nonselective+ET(A/B)+and+a+selective+ET(A)+antagonist+in+rats+with+monocrotaline-induced+pulmonary+hypertension.">Effectiveness of a nonselective ET(A/B) and a selective ET(A) antagonist in rats with monocrotaline-induced pulmonary hypertension.</a> Circulation. 103 (2), 314-318 (2001).</li><li>Stenmark, K. R., Meyrick, B., Galie, N., Mooi, W. J., McMurtry, I. 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G., 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=Guidelines+for+the+echocardiographic+assessment+of+the+right+heart+in+adults:+a+report+from+the+American+Society+of+Echocardiography+endorsed+by+the+European+Association+of+Echocardiography,+a+registered+branch+of+the+European+Society+of+Cardiology,+and+the+Canadian+Society+of+Echocardiography.">Guidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography endorsed by the European Association of Echocardiography, a registered branch of the European Society of Cardiology, and the Canadian Society of Echocardiography.</a> Journal of the American Society of Echocardiography. 23 (7), 685-713 (2010).</li><li>Jones, N., Burns, A. T., Prior, D. L. <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+ventricle-state+of+the+art.">Echocardiographic assessment of the right ventricle-state of the art.</a> Heart Lung and Circulation. 28 (9), 1339-1350 (2019).</li><li>Spyropoulos, F., 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=Echocardiographic+markers+of+pulmonary+hemodynamics+and+right+ventricular+hypertrophy+in+rat+models+of+pulmonary+hypertension.">Echocardiographic markers of pulmonary hemodynamics and right ventricular hypertrophy in rat models of pulmonary hypertension.</a> Pulmonary Circulation. 10 (2), 2045894020910976 (2020).</li><li>Armstrong, W. F., Ryan, T., Feigenbaum, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Feigenbaum's echocardiography. 7th edn. , (2010).</li><li>Kimura, K., 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=Evaluation+of+right+ventricle+by+speckle+tracking+and+conventional+echocardiography+in+rats+with+right+ventricular+heart+failure.">Evaluation of right ventricle by speckle tracking and conventional echocardiography in rats with right ventricular heart failure.</a> International Heart Journal. 56 (3), 349-353 (2015).</li><li>Cheng, H. W., 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=Assessment+of+right+ventricular+structure+and+function+in+mouse+model+of+pulmonary+artery+constriction+by+transthoracic+echocardiography.">Assessment of right ventricular structure and function in mouse model of pulmonary artery constriction by transthoracic echocardiography.</a> Journal of Visualized Experiments. 84, e51041 (2014).</li><li>Mazurek, J. A., Vaidya, A., Mathai, S. C., Roberts, J. D., Forfia, P. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Follow-up+tricuspid+annular+plane+systolic+excursion+predicts+survival+in+pulmonary+arterial+hypertension.">Follow-up tricuspid annular plane systolic excursion predicts survival in pulmonary arterial hypertension.</a> Pulmonary Circulation. 7 (2), 361-371 (2017).</li><li>Grapsa, 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=Echocardiographic+and+hemodynamic+predictors+of+survival+in+precapillary+pulmonary+hypertension:+seven-year+follow-up.">Echocardiographic and hemodynamic predictors of survival in precapillary pulmonary hypertension: seven-year follow-up.</a> Circulation: Cardiovascular Imaging. 8 (6), 002107 (2015).</li><li>Bernardo, I., Wong, J., Wlodek, M. E., Vlahos, R., Soeding, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+right+heart+function+in+a+rat+model+using+modified+echocardiographic+views.">Evaluation of right heart function in a rat model using modified echocardiographic views.</a> PLoS One. 12 (10), 0187345 (2017).</li></ol>

The authors have nothing to disclose.

Echocardiographic evaluation of the RV is a valuable discovery tool for the screening of the effectiveness of novel treatments in animal models of PAH. In-depth characterization of the RV structure and function is necessary as novel targets in treating PAH address RV remodeling4,14. This study describes a detailed protocol that allows for the successful characterization of RV structure and function.
The complex structural geometry and ...

PAH is a progressive disease defined as a mean pulmonary arterial pressure at rest of greater than 20 mmHg1. Pathological changes in PAH include pulmonary artery (PA) remodeling, vasoconstriction, inflammation, and fibroblast activation and proliferation. These pathological changes lead to increased pulmonary vascular resistance and, consequently, right ventricular remodeling, hypertrophy, and failure2. PAH is a complex disease that involves crosstalk between several signaling pathways. The currently approved drugs for treating PAH mostly target vasodilator pathways, including the nitric oxide-cyclic guanosine monophosphate pathway, prostacyclin pathway, and endothelin pathway. Therapeutics targeting these pathways have been used as both monotherapies and in combination therapies3,4. Despite the advances in treatment for PAH in the last decade, findings from the US-based REVEAL registry show a poor 5 year survival rate for newly diagnosed patients5. More recently, emerging therapeutic modalities have focused on disease-modifying agents that can impact the multifactorial pathophysiology of the vascular remodeling occurring in PAH in the hope of disrupting the disease6.
Animal models of PAH are invaluable tools in assessing the efficacy of new drug treatments. The MCT-induced PAH rat model is a widely used animal model characterized by remodeling of the pulmonary arterial vessels, which in turn leads to increased pulmonary vascular resistance and right ventricular hypertrophy and dysfunction7,8. To assess the efficacy of new treatments, researchers normally focus on the terminal assessment of RV pressure without considering the longitudinal evaluation of PA pressure, RV morphology, and RV function. The use of noninvasive and non-terminal imaging techniques is crucial for a comprehensive examination of disease progression in animal models. Transthoracic echocardiography remains the standard approach to evaluating heart morphology and function in animal models due to its low cost and ease of use compared to other imaging modalities, such as magnetic resonance imaging. However, echocardiographic evaluation of the RV can be challenging due to the RV positioning beneath the sternum shadow, its well-developed trabeculation, and its anatomical shape, all of which make it difficult to delineate the endocardial border9,10,11.
This article aims to describe a comprehensive protocol to evaluate RV dimensions, areas and volumes, and systolic and diastolic function in naive and MCT-induced PAH in Sprague Dawley (SD) rats. Additionally, this protocol details a method to assess echocardiographic dimensions in the normal and dilated right atrium.

<table><tbody><tr><td>0.9% sodium cloride injection USP</td><td>Baxter</td><td>2B1324</td><td></td></tr><tr><td>Braided cotton rolls</td><td>4MD Medical Solutions</td><td>RIHD201205</td><td></td></tr><tr><td>Depilating agent</td><td>Wallgreens</td><td>Nair Hair Remover&amp;nbsp;</td><td></td></tr><tr><td>Electrode gel</td><td>Parker Laboratories&amp;nbsp;</td><td>15-60</td><td></td></tr><tr><td>High frequency ultrasound image system and imaging station</td><td>FUJIFILM VisualSonics, Inc.</td><td>Vevo 2100</td><td></td></tr><tr><td>Isoflurane</td><td>MedVet</td><td>RXISO-250</td><td></td></tr><tr><td>Male sprague Dawley rats</td><td>Charles River Laboratories</td><td>CD 001</td><td>CD IGS Rats (Crl:CD(SD))</td></tr><tr><td>Monocrotaline (MCT)</td><td>Sigma-Aldrich</td><td>C2401</td><td></td></tr><tr><td>Rectal temperature probe &amp;nbsp;</td><td>Physitemp&amp;nbsp;</td><td>RET-3</td><td></td></tr><tr><td>Sealed induction chambers</td><td>Scivena Scientific</td><td>RES644&amp;nbsp;</td><td>3 L size</td></tr><tr><td>Solid-state array ultrasound transducer</td><td>FUJIFILM VisualSonics, Inc.</td><td>Vevo MicroScan transducer MS250S</td><td></td></tr><tr><td>Stainless steel digital calipers</td><td>VWR Digital Calipers</td><td>62379-531</td><td></td></tr><tr><td>Ultrasound gel&amp;nbsp;</td><td>Parker Laboratories&amp;nbsp;</td><td>11-08</td><td></td></tr><tr><td>Vevo Lab software</td><td>FUJIFILM VisualSonics, Inc.</td><td></td><td>Verison 5.5.1</td></tr></tbody></table>

comprehensive echocardiographic assessment of right ventricle function in a rat model of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a progressive disease caused by vasoconstriction and remodeling of the small arteries in the lungs. This remodeling leads to increased pulmonary vascular resistance, worsened right ventricular function, and premature death. Currently approved therapies for PAH largely target pulmonary vasodilator pathways; however, recent emerging therapeutic modalities are focused on other novel pathways involved in the pathogenesis of the disease, including right ventricle (RV) remodeling. Imaging techniques that allow longitudinal assessment of novel therapeutics are very useful for determining the efficacy of new drugs in preclinical studies. Noninvasive trans-thoracic echocardiography remains the standard approach to evaluating heart function and is widely used in rodent models. However, echocardiographic evaluation of the RV can be challenging due to its anatomical position and structure. In addition, standardized guidelines are lacking for echocardiography&#160;in preclinical rodent models, making it difficult to carry out a uniform assessment of RV&#160;function across studies in different laboratories. In preclinical studies, the monocrotaline (MCT) injury model in rats is widely used to evaluate drug efficacy for treating PAH. This protocol describes the echocardiographic evaluation of the RV in na&#239;ve and MCT-induced PAH rats.

In this study, MCT-treated rats were used as a model of PAH. Echocardiographic analysis was performed on Study Day 23 post-MCT administration, and all measurements and calculations represented averages from three consecutive cycles. Echocardiographic parameters obtained from control (vehicle: deionized water) and MCT-treated (60 mg/kg) rats are shown in Table 1.
Representative images of the PLAX view in control and MCT-treated rats are shown in Figure 1A</...

Watch this Scientific Journal Video about Comprehensive Echocardiographic Assessment of Right Ventricle Function in a Rat Model of Pulmonary Arterial Hypertension at JoVE.com

Comprehensive Echocardiographic Assessment of Right Ventricle Function in a Rat Model of Pulmonary Arterial Hypertension

The present protocol describes the echocardiographic characterization of right ventricular morphology and function in a rat model of pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a progressive disease caused by vasoconstriction and remodeling of the small arteries in the lungs. This ...

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3.3K Views.  University of Illinois at Chicago. The present protocol describes the echocardiographic characterization of right ventricular morphology and function in a rat model of pulmonary arterial hypertension.

Video: Comprehensive Echocardiographic Assessment of Right Ventricle Function in a Rat Model of Pulmonary Arterial Hypertension

Echocardiographic Assessment of the Right Heart in Mice

Transgenic and toxic models of pulmonary arterial hypertension (PAH) are widely used to study the pathophysiology of PAH and to investigate potential therapies. Given the expense and time involved in creating animal models of disease, it is critical that researchers have tools to accurately assess phenotypic expression of disease. Right ventricular dysfunction is the major manifestation of pulmonary hypertension. Echocardiography is the mainstay of the noninvasive assessment of right ventricular function in rodent models and has the advantage of clear translation to humans in whom the same tool is used. Published echocardiography protocols in murine models of PAH are lacking.
In this article, we describe a protocol for assessing RV and pulmonary vascular function in a mouse model of PAH with a dominant negative BMPRII mutation; however, this protocol is applicable to any diseases affecting the pulmonary vasculature or right heart. We provide a detailed description of animal preparation, image acquisition and hemodynamic calculation of stroke volume, cardiac output and an estimate of pulmonary artery pressure.

This article provides a protocol for the echocardiographic assessment of right ventricular size and pulmonary hypertension in mice. Applications include phenotype determination and serial assessment in transgenic and toxin-induced mouse models of cardiomyopathy and pulmonary vascular disease.

Transgenic and toxic models of pulmonary arterial hypertension (PAH) are widely used to study the pathophysiology of PAH and to investigate potential ...

Medicine

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.

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

Chronic Thromboembolic Pulmonary Hypertension and Assessment of Right Ventricular Function in the Piglet

An original piglet model of Chronic Thromboembolic Pulmonary Hypertension (CTEPH) associated with chronic Right Ventricular (RV) dysfunction is described. Pulmonary Hypertension (PH) was induced in 3-week-old piglets by a progressive obstruction of the pulmonary vascular bed. A ligation of the left Pulmonary Artery (PA) was performed first through a mini-thoracotomy. Second, weekly embolizations of the right lower pulmonary lobe were done under fluoroscopic guidance with n-butyl-2-cyanoacrylate during 5 weeks. Mean Pulmonary Arterial Pressure (mPAP) measured by ritght heart catheterism, increased progressively, as well as Right Atrial pressure and Pulmonary Vascular Resistances (PVR) after 5 weeks compared to sham animals. Right Ventricular (RV) structural and functional remodeling were assessed by transthoracic echocardiography (RV diameters, RV wall thickness, RV systolic function). RV elastance and RV-pulmonary coupling were assessed by Pressure-Volume Loops (PVL) analysis with conductance method. Histologic study of the lung and the right ventricle were also performed. Molecular analyses on RV fresh tissues could be performed through repeated transcutaneous endomyocardial biopsies. Pulmonary microvascular disease in obstructed and unobstructed territories was studied from lung biopsies using molecular analyses and pathology. Furthermore, the reliability and the reproducibility was associated with a range of PH severity in animals. Most aspects of the human CTEPH disease were reproduced in this model, which allows new perspectives for the understanding of the underlying mechanisms (mitochondria, inflammation) and new therapeutic approaches (targeted, cellular or gene therapies) of the overloaded right ventricle but also pulmonary microvascular disease.

Chronic Thromboembolic Pulmonary Hypertension (CTEPH) and Right Ventricular (RV) dysfunction were induced in piglets by progressive obstruction of the pulmonary arteries. Consequences were remarkably similar to those observed in CTEPH patients. This animal model would be a very useful tool for pathophysiology and therapeutic experiments on CTEPH and RV failure.

An original piglet model of Chronic Thromboembolic Pulmonary Hypertension (CTEPH) associated with chronic Right Ventricular (RV) dysfunction is described. ...

Hemodynamic Characterization of Rodent Models of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a rare disease of the pulmonary vasculature characterized by endothelial cell apoptosis, smooth muscle proliferation and obliteration of pulmonary arterioles. This in turn results in right ventricular (RV) failure, with significant morbidity and mortality. Rodent models of PAH, in the mouse and the rat, are important for understanding the pathophysiology underlying this rare disease. Notably, different models of PAH may be associated with different degrees of pulmonary hypertension, RV hypertrophy and RV failure. Therefore, a complete hemodynamic characterization of mice and rats with PAH is critical in determining the effects of drugs or genetic modifications on the disease. 
Here we demonstrate standard procedures for assessment of right ventricular function and hemodynamics in both rat and mouse PAH models. Echocardiography is useful in determining RV function in rats, although obtaining standard views of the right ventricle is challenging in the awake mouse. Access for right heart catheterization is obtained by the internal jugular vein in closed-chest mice and rats. Pressures can be measured using polyethylene tubing with a fluid pressure transducer or a miniature micromanometer pressure catheter. Pressure-volume loop analysis can be performed in the open chest. After obtaining hemodynamics, the rodent is euthanized. The heart can be dissected to separate the RV free wall from the left ventricle (LV) and septum, allowing an assessment of RV hypertrophy using the Fulton index (RV/(LV+S)). Then samples can be harvested from the heart, lungs and other tissues as needed.

Pulmonary arterial hypertension (PAH) is a disease of pulmonary arterioles that leads to their obliteration and the development of right ventricular failure. Rodent models of PAH are critical in understanding the pathophysiology of PAH. Here we demonstrate hemodynamic characterization, with right heart catheterization and echocardiography, in the mouse and rat.

Pulmonary arterial hypertension (PAH) is a rare disease of the pulmonary vasculature characterized by endothelial cell apoptosis, smooth muscle ...

Invasive Hemodynamic Monitoring of Aortic and Pulmonary Artery Hemodynamics in a Large Animal Model of ARDS

One of the leading causes of morbidity and mortality in patients with heart failure is right ventricular (RV) dysfunction, especially if it is due to pulmonary hypertension. For a better understanding and treatment of this disease, precise hemodynamic monitoring of left and right ventricular parameters is important. For this reason, it is essential to establish experimental pig models of cardiac hemodynamics and measurements for research purpose. 
This article shows the induction of ARDS by using oleic acid (OA) and consequent right ventricular dysfunction, as well as the instrumentation of the pigs and the data acquisition process that is needed to assess hemodynamic parameters. To achieve right ventricular dysfunction, we used oleic acid (OA) to cause ARDS and accompanied this with pulmonary artery hypertension (PAH). With this model of PAH and consecutive right ventricular dysfunction, many hemodynamic parameters can be measured, and right ventricular volume load can be detected. 
All vital parameters, including respiratory rate (RR), heart rate (HR) and body temperature were recorded throughout the whole experiment. Hemodynamic parameters including femoral artery pressure (FAP), aortic pressure (AP), right ventricular pressure (peak systolic, end systolic and end diastolic right ventricular pressure), central venous pressure (CVP), pulmonary artery pressure (PAP) and left arterial pressure (LAP) were measured as well as perfusion parameters including ascending aortic flow (AAF) and pulmonary artery flow (PAF). Hemodynamic measurements were performed using transcardiopulmonary thermodilution to provide cardiac output (CO). Furthermore, the PiCCO2 system (Pulse Contour Cardiac Output System 2) was used to receive parameters such as stroke volume variance (SVV), pulse pressure variance (PPV), as well as extravascular lung water (EVLW) and global end-diastolic volume (GEDV). Our monitoring procedure is suitable for detecting right ventricular dysfunction and monitoring hemodynamic findings before and after volume administration.

We present a protocol of creating right ventricular dysfunction in a pig model by inducing ARDS. We demonstrate invasive monitoring of left and right ventricular cardiac output using flow probes around the aorta and the pulmonary artery, as well as blood pressure measurements in the aorta and pulmonary artery.

One of the leading causes of morbidity and mortality in patients with heart failure is right ventricular (RV) dysfunction, especially if it is due to ...

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.

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 ...

Induction and Phenotyping of Acute Right Heart Failure in a Large Animal Model of Chronic Thromboembolic Pulmonary Hypertension

The development of acute right heart failure (ARHF) in the context of chronic pulmonary hypertension (PH) is associated with poor short-term outcomes. The morphological and functional phenotyping of the right ventricle is of particular importance in the context of hemodynamic compromise in patients with ARHF. Here, we describe a method to induce ARHF in a previously described large animal model of chronic PH, and to phenotype, dynamically, right ventricular function using the gold standard method (i.e., pressure-volume PV loops) and with a non-invasive clinically available method (i.e., echocardiography). Chronic PH is first induced in pigs by left pulmonary artery ligation and right lower lobe embolism with biological glue once a week for 5 weeks. After 16 weeks, ARHF is induced by successive volume loading using saline followed by iterative pulmonary embolism until the ratio of the systolic pulmonary pressure over systemic pressure reaches 0.9 or until the systolic systemic pressure decreases below 90 mmHg. Hemodynamics are restored with dobutamine infusion (from 2.5 &#181;g/kg/min to 7.5 &#181;g/kg/min). PV-loops and echocardiography are performed during each condition. Each condition requires around 40 minutes for induction, hemodynamic stabilization and data acquisition. Out of 9 animals, 2 died immediately after pulmonary embolism and 7 completed the protocol, which illustrates the learning curve of the model. The model induced a 3-fold increase in mean pulmonary artery pressure. The PV-loop analysis showed that ventriculo-arterial coupling was preserved after volume loading, decreased after acute pulmonary embolism and was restored with dobutamine. Echocardiographic acquisitions allowed to quantify right ventricular parameters of morphology and function with good quality. We identified right ventricular ischemic lesions in the model. The model can be used to compare different treatments or to validate non-invasive parameters of right ventricular morphology and function in the context of ARHF.

We present a protocol to induce and phenotype an acute right heart failure in a large animal model with chronic pulmonary hypertension. This model can be used to test therapeutic interventions, to develop right heart metrics&#160;or to improve the understanding of acute right heart failure pathophysiology.

The development of acute right heart failure (ARHF) in the context of chronic pulmonary hypertension (PH) is associated with poor short-term outcomes. The ...

Invasive Hemodynamic Assessment for the Right Ventricular System and Hypoxia-Induced Pulmonary Arterial Hypertension in Mice

Pulmonary arterial hypertension (PAH) is a chronic and severe cardiopulmonary disorder. Mice are a popular animal model used to mimic this disease. However, the evaluation of right ventricular pressure (RVP) and pulmonary artery pressure (PAP) remains technically challenging in mice. RVP and PAP are more difficult to measure than left ventricular pressure because of the anatomical differences between the left and right heart systems. In this paper, we describe a stable right heart hemodynamic measurement method and its validation using healthy and PAH mice. This method is based on open-chest surgery and mechanical ventilation support. It is a complicated procedure compared to closed chest procedures. While a well-trained surgeon is required for this surgery, the advantage of this procedure is that it can generate both RVP and PAP parameters at the same time, so it is a preferable procedure for the evaluation of PAH models.

Here, we present a protocol to perform an invasive hemodynamic assessment of the right ventricle and pulmonary artery in mice using an open-chest surgery approach.

Pulmonary arterial hypertension (PAH) is a chronic and severe cardiopulmonary disorder. Mice are a popular animal model used to mimic this disease. ...

Echocardiographic Assessment of Cardiac Anatomy and Function in Adult Rats

The use of experimental animal models has become crucial in cardiovascular science. Most studies using rodent models are focused on two-dimensional imaging to study the cardiac anatomy of the left ventricle and M-mode echo to assess its dimensions. However, this could limit a comprehensive study. Herein, we describe a protocol that allows an assessment of the heart chamber size, left ventricular function (systolic and diastolic) and valvular function. A conventional medical ultrasound machine was used in this protocol and different echo views were obtained through left parasternal, apical and suprasternal windows. In the left parasternal window, the long and short axis were acquired to analyze left chamber dimensions, right ventricle and pulmonary artery dimensions, and mitral, pulmonary and aortic valve function. The apical window allows the measurement of heart chamber dimensions and evaluation of systolic and diastolic parameters. It also allows Doppler assessment with detection and quantification of heart valve disturbances (regurgitation or stenosis). Different segments and walls of the left ventricle are visualized throughout all views. Finally, the ascending aorta, aortic arch, and descending aorta can be imaged through the suprasternal window. A combination of ultrasound imaging, Doppler flow and tissue Doppler assessment have been obtained to study cardiac morphology and function. This represents an important contribution to improve the assessment of cardiac function in adult rats with impact for research using these animal models.

A non-invasive protocol for transthoracic echocardiography assessment of cardiac anatomy and function for adult rats is presented in the current study. The heart valves, all four cardiac chambers and the ascending aorta, aortic arch and descending aorta are studied in detail.

The use of experimental animal models has become crucial in cardiovascular science. Most studies using rodent models are focused on two-dimensional ...

Induction of Right Ventricular Failure by Pulmonary Artery Constriction and Evaluation of Right Ventricular Function in Mice

The mechanism of right ventricular failure (RVF) requires clarification due to the uniqueness, high morbidity, high mortality, and refractory nature of RVF. Previous rat models imitating RVF progression have been described. Compared with rats, mice are more accessible, economical, and widely used in animal experiments. We developed a pulmonary artery constriction (PAC) approach which is comprised of banding the pulmonary trunk in mice to induce right ventricular (RV) hypertrophy. A special surgical latch needle was designed that allows for easier separation of the aorta and the pulmonary trunk. In our experiments, the use of this fabricated latch needle reduced the risk of arteriorrhexis and improved the surgical success rate to 90%. We used different padding needle diameters to precisely create quantitative constriction, which can induce different degrees of RV hypertrophy. We quantified the degree of constriction by evaluating the blood flow velocity of the PA, which was measured by noninvasive transthoracic echocardiography. RV function was precisely evaluated by right heart catheterization at 8 weeks after surgery. The surgical instruments made inhouse were composed of common materials using a simple process that is easy to master. Therefore, the PAC approach described here is easy to imitate using instruments made in the lab and can be widely used in other labs. This study presents a modified PAC approach that has a higher success rate than other models and an 8-week postsurgery survival rate of 97.8%. This PAC approach provides a useful technique for studying the mechanism of RVF and will enable an increased understanding of RVF.

Here, we provide a useful approach for studying the mechanism of right ventricular failure. A more convenient and efficient approach to pulmonary artery constriction is established using surgical instruments made inhouse. In addition, methods to evaluate the quality of this approach by echocardiography and catheterization are provided.

The mechanism of right ventricular failure (RVF) requires clarification due to the uniqueness, high morbidity, high mortality, and refractory nature of ...