This work was supported by the Laerdal Foundation for Acute Medicine (3374), Holger and Ruth Hesse&#39;s Memorial Foundation, S&#248;ster and Verner Lippert&#39;s Foundation, Novo Nordisk Foundation (NNF16OC0023244, NFF17CO0024868), and Alfred Benzon&#39;s Foundation.

This protocol was developed and utilized for studies conducted in compliance with the Danish and Institutional guidelines on animal welfare and ethics. The Danish Animal Research Inspectorate approved the study (license no. 2016-15-0201-00840). A Danish, female slaughter pig (crossbreed of Landrace, Yorkshire, and Duroc) of approximately 60 kg was used.
1. Anesthesia and ventilation
<ol>
	<li>Pre-anesthetize the awake pig with Zoletil mix 1 mL/kg (see Table of Materials) as ...

<ol>
	<li>Burkhoff, D., Mirsky, I., Suga, H. <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+systolic+and+diastolic+ventricular+properties+via+pressure-volume+analysis:+a+guide+for+clinical,+translational,+and+basic+researchers.">Assessment of systolic and diastolic ventricular properties via pressure-volume analysis: a guide for clinical, translational, and basic researchers.</a> American Journal of Physiology-Heart and Circulatory Physiology. 289 (2), 501-512 (2005).</li><li>Sagawa, K., Suga, H., Shoukas, A. A., Bakalar, K. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=End-systolic+pressure/volume+ratio:+A+new+index+of+ventricular+contractility.">End-systolic pressure/volume ratio: A new index of ventricular contractility.</a> American Journal of Cardiology. 40 (5), 748-753 (1977).</li><li>Chantler, P. D., Lakatta, E. G., Najjar, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Arterial-ventricular+coupling:+mechanistic+insights+into+cardiovascular+performance+at+rest+and+during+exercise.">Arterial-ventricular coupling: mechanistic insights into cardiovascular performance at rest and during exercise.</a> Journal of Applied Physiology. 105 (4), 1342-1351 (2008).</li><li>Axell, R. 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=Ventriculo-arterial+coupling+detects+occult+RV+dysfunction+in+chronic+thromboembolic+pulmonary+vascular+disease.">Ventriculo-arterial coupling detects occult RV dysfunction in chronic thromboembolic pulmonary vascular disease.</a> Physiological Reports. 5 (7), 13227 (2017).</li><li>Houser, S. R., 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=Animal+models+of+heart+failure.">Animal models of heart failure.</a> Circulation Research. 111 (1), 131-150 (2012).</li><li>Lahm, T., 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+function+in+the+research+setting:+knowledge+gaps+and+pathways+forward.+An+official+american+thoracic+society+research+statement.">Assessment of right ventricular function in the research setting: knowledge gaps and pathways forward. An official american thoracic society research statement.</a> American Journal of Respiratory and Critical Care Medicine. 198 (4), e15-e43 (2018).</li><li>Morimont, 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=Effective+arterial+elastance+as+an+index+of+pulmonary+vascular+load.">Effective arterial elastance as an index of pulmonary vascular load.</a> American Journal of Physiology - Heart and Circulatory Physiology. 294 (6), 2736-2742 (2008).</li><li>Kutty, 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=Validation+of+admittance+computed+left+ventricular+volumes+against+real-time+three-dimensional+echocardiography+in+the+porcine+heart.">Validation of admittance computed left ventricular volumes against real-time three-dimensional echocardiography in the porcine heart.</a> Experimental Physiology. 98 (6), 1092-1101 (2013).</li><li>Bove, T., 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=Acute+and+chronic+effects+of+dysfunction+of+right+ventricular+outflow+tract+components+on+right+ventricular+performance+in+a+porcine+model:+Implications+for+primary+repair+of+tetralogy+of+fallot.">Acute and chronic effects of dysfunction of right ventricular outflow tract components on right ventricular performance in a porcine model: Implications for primary repair of tetralogy of fallot.</a> Journal of the American College of Cardiology. 60 (1), 64-71 (2012).</li><li>Townsend, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measuring+pressure+volume+loops+in+the+mouse.">Measuring pressure volume loops in the mouse.</a> Journal of Visualized Experiments. (111), e53810 (2016).</li><li>Belenkie, I., Smith, E. R., Tyberg, J. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ventricular+interaction:+From+bench+to+bedside.">Ventricular interaction: From bench to bedside.</a> Annals of Medicine. 33 (4), 236-241 (2009).</li><li>LaCorte, J. C., 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=Correlation+of+the+TIE+index+with+invasive+measurements+of+ventricular+function+in+a+porcine+model.">Correlation of the TIE index with invasive measurements of ventricular function in a porcine model.</a> Journal of the American Society of Echocardiography. 16 (5), 442-447 (2003).</li><li>Am&#224;, R., Leather, H. A., Segers, P., Vandermeersch, E., Wouters, P. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acute+pulmonary+hypertension+causes+depression+of+left+ventricular+contractility+and+relaxation.">Acute pulmonary hypertension causes depression of left ventricular contractility and relaxation.</a> European Journal of Anaesthesiology. 23 (10), 824-831 (2006).</li><li>Missant, C., Rex, S., Segers, P., Wouters, P. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Levosimendan+improves+right+ventriculovascular+coupling+in+a+porcine+model+of+right+ventricular+dysfunction.">Levosimendan improves right ventriculovascular coupling in a porcine model of right ventricular dysfunction.</a> Critical Care Medicine. 35 (3), 707-715 (2007).</li><li>Mortensen, C. 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=Impact+of+preload+on+right+ventricular+hemodynamics+in+acute+pulmonary+embolism.">Impact of preload on right ventricular hemodynamics in acute pulmonary embolism.</a> Critical Care Medicine. 48 (12), 1306-1312 (2020).</li><li>Kramer, 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=Inhaled+nitric+oxide+has+pulmonary+vasodilator+efficacy+both+in+the+immediate+and+prolonged+phase+of+acute+pulmonary+embolism.">Inhaled nitric oxide has pulmonary vasodilator efficacy both in the immediate and prolonged phase of acute pulmonary embolism.</a> European Heart Journal: Acute Cardiovascular Care. , 204887262091871 (2020).</li><li>Lyhne, M. D., 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=Oxygen+therapy+lowers+right+ventricular+afterload+in+experimental+acute+pulmonary+embolism.">Oxygen therapy lowers right ventricular afterload in experimental acute pulmonary embolism.</a> Critical Care Medicine. , (2021).</li><li>Lyhne, M. D., 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+adaptation+in+the+critical+phase+after+acute+intermediate-risk+pulmonary+embolism.">Right ventricular adaptation in the critical phase after acute intermediate-risk pulmonary embolism.</a> European Heart Journal: Acute Cardiovascular Care. , 204887262092525 (2020).</li><li>Dietrichs, E. S., Tveita, T., Smith, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hypothermia+and+cardiac+electrophysiology:+a+systematic+review+of+clinical+and+experimental+data.">Hypothermia and cardiac electrophysiology: a systematic review of clinical and experimental data.</a> Cardiovascular Research. 115 (3), 501-509 (2018).</li><li>Boulate, D., 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=Early+development+of+right+ventricular+ischemic+lesions+in+a+novel+large+animal+model+of+acute+right+heart+failure+in+chronic+thromboembolic+pulmonary+hypertension.">Early development of right ventricular ischemic lesions in a novel large animal model of acute right heart failure in chronic thromboembolic pulmonary hypertension.</a> Journal of Cardiac Failure. 23 (12), 876-886 (2017).</li><li>Haney, M. 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=Myocardial+systolic+function+increases+during+positive+pressure+lung+inflation.">Myocardial systolic function increases during positive pressure lung inflation.</a> Anesthesia and Analgesia. 101 (5), 1269-1274 (2005).</li><li>Gorcsan, J., Strum, D. P., Mandarino, W. A., Gulati, V. K., Pinsky, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+assessment+of+alterations+in+regional+left+ventricular+contractility+with+color-coded+tissue+doppler+echocardiography:+Comparison+with+sonomicrometry+and+pressure-volume+relations.">Quantitative assessment of alterations in regional left ventricular contractility with color-coded tissue doppler echocardiography: Comparison with sonomicrometry and pressure-volume relations.</a> Circulation. 95 (10), 2423-2433 (1997).</li><li>Pinsky, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamic+right+and+left+ventricular+interactions+in+the+pig.">Dynamic right and left ventricular interactions in the pig.</a> Experimental Physiology. 105 (8), 1293-1315 (2020).</li><li>Mitchell, J. R., 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=RV+filling+modulates+LV+function+by+direct+ventricular+interaction+during+mechanical+ventilation.">RV filling modulates LV function by direct ventricular interaction during mechanical ventilation.</a> American Journal of Physiology-Heart and Circulatory Physiology. 289 (2), 549-557 (2005).</li><li>Larson, E. R., Feldman, M. D., Valvano, J. W., Pearce, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+the+spatial+sensitivity+of+conductance/admittance+catheter+ventricular+volume+estimation.">Analysis of the spatial sensitivity of conductance/admittance catheter ventricular volume estimation.</a> IEEE Transactions on Biomedical Engineering. 60 (8), 2316-2324 (2013).</li><li>Hout, G. P. 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=Admittance-based+pressure-volume+loops+versus+gold+standard+cardiac+magnetic+resonance+imaging+in+a+porcine+model+of+myocardial+infarction.">Admittance-based pressure-volume loops versus gold standard cardiac magnetic resonance imaging in a porcine model of myocardial infarction.</a> Physiological Reports. 2 (4), 00287 (2014).</li><li>Baker, A. E., Dani, R., Smith, E. R., Tyberg, J. V., Belenkie, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+assessment+of+independent+contributions+of+pericardium+and+septum+to+direct+ventricular+interaction.">Quantitative assessment of independent contributions of pericardium and septum to direct ventricular interaction.</a> American Journal of Physiology-Heart and Circulatory Physiology. 275 (2), 476-483 (1998).</li><li>Sanz, J., S&#225;nchez-Quintana, D., Bossone, E., Bogaard, H. J., Naeije, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anatomy,+function,+and+dysfunction+of+the+right+ventricle.">Anatomy, function, and dysfunction of the right ventricle.</a> Journal of the American College of Cardiology. 73 (12), 1463-1482 (2019).</li><li>Gavazzoni, 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=Prognostic+value+of+right+ventricular+free+wall+longitudinal+strain+in+a+large+cohort+of+outpatients+with+left-side+heart+disease.">Prognostic value of right ventricular free wall longitudinal strain in a large cohort of outpatients with left-side heart disease.</a> European Heart Journal: Cardiovascular Imaging. 21 (9), 1013-1021 (2019).</li><li>Berglund, F., Pi&#241;a, P., Herrera, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Right+ventricle+in+heart+failure+with+preserved+ejection+fraction.">Right ventricle in heart failure with preserved ejection fraction.</a> Heart. 106 (23), 1798-1804 (2020).</li></ol>

None of the authors has any conflicts of interest to declare.

This paper describes a reproducible minimally invasive closed chest approach for bi-ventricular pressure-volume loop recordings.
Advancement of the PV catheter from the RA into the RV is the most critical step in this protocol. The complex composition of the RV and the stiffness of the catheter complicate insertion into the easily distended and geometrically challenging RV. This difficulty may explain why open chest instrumentation is often preferred. During pilot studies, numerous accesses an...

Pressure-volume (PV) loops contain a large number of hemodynamic information, including end-systolic and end-diastolic pressures and volumes, ejection fraction, stroke volume, and stroke work1. Furthermore, transient preload reduction creates a family of loops from which load-independent variables can be derived2,3. This load-independent evaluation of ventricular function makes PV loop recordings state-of-the-art in hemodynamic evaluation. PV loop recording can be performed in humans but is primarily used and recommended in preclinical research4,5,6.
Pressure-volume loops can be obtained from both the right ventricle (RV) and the left ventricle (LV). Most research hypotheses are focused on a single ventricle, resulting in only univentricular PV loops being recorded7,8,9,10. However, the right and left ventricles exert systolic and diastolic interdependence due to their serial and parallel connections within the tight pericardium11. Changes in the output or the size of one ventricle will affect the size, loading conditions, or perfusion of the other ventricle. Thus, bi-ventricular PV loop recordings provide a more comprehensive evaluation of the total cardiac performance. Pharmacological interventions may also affect the two ventricles and their loading conditions differently, further emphasizing the importance of bi-ventricular evaluation.
PV catheters can be advanced into either ventricle by several approaches, including open chest approach with access from the apex of the heart or through the RV outflow tract7,10,12,13,14. However, the opening of the thorax will affect the physiological conditions and may introduce bias.
Based on our experience from previous studies15,16,17,18, we aim to present our closed chest approach to bi-ventricular PV loop recordings in a large animal model of acute RV failure having minimal influence on cardiopulmonary physiology (Figure 1).

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>12L-RS</td>
			<td>GE Healthcare Japan</td>
			<td>5141337</td>
			<td>Ultrasound probe</td>
		</tr>
		<tr>
			<td>Adhesive Aperature Drape (OneMed)</td>
			<td>evercare</td>
			<td>1515-01</td>
			<td>75 x 90 cm (hole: 6 x 8 cm)</td>
		</tr>
		<tr>
			<td>Alaris GP Guardrails plus</td>
			<td>CareFusion</td>
			<td>9002TIG01-G</td>
			<td>Infusion pump</td>
		</tr>
		<tr>
			<td>Alaris Infusion set</td>
			<td>BD Plastipak</td>
			<td>60593</td>
			<td></td>
		</tr>
		<tr>
			<td>Alkoholswap</td>
			<td>MEDIQ Danmark</td>
			<td>3340012</td>
			<td>82% ethanol, 0,5% chlorhexidin, skin disinfection</td>
		</tr>
		<tr>
			<td>Amplatz Support Wire Guide Extra-Stiff</td>
			<td>Cook Medical</td>
			<td>THSF-25-260-AES</td>
			<td>diameter: 0.025 inches, length: 260 cm</td>
		</tr>
		<tr>
			<td>BD Connecta</td>
			<td>BD</td>
			<td>394601</td>
			<td>Luer-Lock</td>
		</tr>
		<tr>
			<td>BD Emerald</td>
			<td>BD</td>
			<td>307736</td>
			<td>10 mL syringe</td>
		</tr>
		<tr>
			<td>BD Luer-Lock</td>
			<td>BD Plastipak</td>
			<td>300865</td>
			<td>BD = Becton Dickinson, 50 mL syringe</td>
		</tr>
		<tr>
			<td>BD Platipak</td>
			<td>BD</td>
			<td>300613</td>
			<td>20 mL syringe</td>
		</tr>
		<tr>
			<td>BD Venflon Pro</td>
			<td>Becton Dickinson Infusion Therapy</td>
			<td>393204</td>
			<td>20G</td>
		</tr>
		<tr>
			<td>BD Venflon Pro</td>
			<td>Becton Dickinson Infusion Therapy</td>
			<td>393208</td>
			<td>17G</td>
		</tr>
		<tr>
			<td>Butomidor Vet</td>
			<td>Richter Pharma AG</td>
			<td>531943</td>
			<td>10 mg/mL</td>
		</tr>
		<tr>
			<td>Check-Flo Performer Introducer</td>
			<td>Cook Medical</td>
			<td>RCFW-16.0P-38-30-RB</td>
			<td>16 F sheath, 30 cm long</td>
		</tr>
		<tr>
			<td>Cios Connect S/N 20015</td>
			<td>Siemens Healthineers</td>
			<td></td>
			<td>C-arm</td>
		</tr>
		<tr>
			<td>D-LCC12A-01</td>
			<td>GE Healthcare Finland</td>
			<td></td>
			<td>Pressure measurement monitor</td>
		</tr>
		<tr>
			<td>Durapore</td>
			<td>3M</td>
			<td>-</td>
			<td>Adhesive tape</td>
		</tr>
		<tr>
			<td>E-PRESTIN-00</td>
			<td>GE Healthcare Finland</td>
			<td>6152932</td>
			<td>Respirator tubes</td>
		</tr>
		<tr>
			<td>Exagon vet</td>
			<td>Richter Pharma AG</td>
			<td>427931</td>
			<td>400 mg/mL</td>
		</tr>
		<tr>
			<td>Fast-Cath Hemostasis Introducer 12F</td>
			<td>St. Jude Medical</td>
			<td>406128</td>
			<td>L: 12 cm</td>
		</tr>
		<tr>
			<td>Favorita II</td>
			<td>Aesculap</td>
			<td></td>
			<td>Type: GT104</td>
		</tr>
		<tr>
			<td>Fentanyl</td>
			<td>B. Braun</td>
			<td>71036</td>
			<td>50 mikrogram/mL</td>
		</tr>
		<tr>
			<td>Ketaminol Vet</td>
			<td>MSD/Intervet International B.V.</td>
			<td>511519</td>
			<td>100 mg/mL</td>
		</tr>
		<tr>
			<td>LabChart</td>
			<td>ADInstruments</td>
			<td></td>
			<td>Data aquisition software</td>
		</tr>
		<tr>
			<td>Lawton 85-0010 ZK1</td>
			<td>Lawton</td>
			<td></td>
			<td>Laryngoscope</td>
		</tr>
		<tr>
			<td>Lectospiral</td>
			<td>VYGON</td>
			<td>1159.90</td>
			<td>400 cm (Luer-LOCK)</td>
		</tr>
		<tr>
			<td>Lubrithal eye gel</td>
			<td>Dechra, Great Britain</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>MBH qufora</td>
			<td>MBH-International A/S</td>
			<td>13853401</td>
			<td>Urine bag</td>
		</tr>
		<tr>
			<td>Natriumklorid</td>
			<td>Fresenius Kabi</td>
			<td>7340022100528</td>
			<td>9 mg/ml Isotonic saline</td>
		</tr>
		<tr>
			<td>PICO50 Aterial Blood Sampler</td>
			<td>Radiometer</td>
			<td>956-552</td>
			<td>2 mL</td>
		</tr>
		<tr>
			<td>Portex Tracheal Tube</td>
			<td>Smiths Medical</td>
			<td>100/150/075</td>
			<td>&#34;Cuffed Clear Oral/Nasal Murphy Eye&#34;</td>
		</tr>
		<tr>
			<td>PowerLab 16/35</td>
			<td>ADInstruments</td>
			<td>PL3516</td>
			<td>Serial number: 3516-1841</td>
		</tr>
		<tr>
			<td>Pressure Extension set</td>
			<td>CODAN</td>
			<td>7,14,020</td>
			<td>Tube for anesthetics, 150 cm long, inner diameter 0.9 mm</td>
		</tr>
		<tr>
			<td>Propolipid</td>
			<td>Fresenius Kabi</td>
			<td>21636</td>
			<td>Propofol, 10 mg/mL</td>
		</tr>
		<tr>
			<td>PTS-X</td>
			<td>NuMED Canada Inc.</td>
			<td>PTSX253</td>
			<td>Inferior vena cava balloon</td>
		</tr>
		<tr>
			<td>Radiofocus Introducer II</td>
			<td>Radiofocus/Terumo</td>
			<td>RS+B80N10MQ</td>
			<td>6+7+8F sheaths</td>
		</tr>
		<tr>
			<td>Rompun Vet</td>
			<td>Beyer</td>
			<td>86450917</td>
			<td>Xylazin, 20 mg/mL</td>
		</tr>
		<tr>
			<td>R&#252;sch Brilliant AquaFlate Glycerine</td>
			<td>Teleflex</td>
			<td>178000</td>
			<td>Bladder catheter, size 14</td>
		</tr>
		<tr>
			<td>S/5 Avance</td>
			<td>Datex-Ohmeda</td>
			<td>-</td>
			<td>Mechanical ventilator</td>
		</tr>
		<tr>
			<td>Safersonic Conti Plus &#38; Safergel</td>
			<td>SECMA medical innovation</td>
			<td>SAF.612.18120.WG.SEC</td>
			<td>18 x 120 cm (Safersonic Sterile Transducer Cover with Adhesive Area and Safergel)</td>
		</tr>
		<tr>
			<td>Scisense Catheter</td>
			<td>Transonic Scisense</td>
			<td>FDH-5018B-E245B</td>
			<td>Serial number: 50-533. Pressure-volume catheter</td>
		</tr>
		<tr>
			<td>Scisense Pressure-Volume Measurement System</td>
			<td>Transonic Scisense</td>
			<td>ADV500</td>
			<td>Model: FY097B. Pressure-volume box</td>
		</tr>
		<tr>
			<td>Swan-Ganz CCOmbo</td>
			<td>Edwards Lifesciences</td>
			<td>744F75</td>
			<td>110 cm</td>
		</tr>
		<tr>
			<td>TruWave Pressure Monitoring Set</td>
			<td>Edwards Lifesciences</td>
			<td>T434303A</td>
			<td>210 cm</td>
		</tr>
		<tr>
			<td>Vivid iq</td>
			<td>GE Medical Systems China</td>
			<td>Vivid iq</td>
			<td></td>
		</tr>
		<tr>
			<td>Zoletil 50 Vet (tiletamin 125 mg and zolazepam 125 mg)</td>
			<td>Virbac</td>
			<td>83046805</td>
			<td>Zoletil Mix for pigs: 1 vial of Zoletil 50 Vet (dry matter); add 6.25 mL Xylozin (20 mg/mL), 1.25 mL ketamin (100 mg/mL) and 2.5 mL Butorphanol (10 mg/mL). Dose for pre-anesthesia: 10 mL/10 kg as intramuscular injection</td>
		</tr>
	</tbody>
</table>

closed chest biventricular pressure-volume loop recordings with admittance catheters in a porcine model

Pressure-volume (PV) loop recording enables the state-of-the-art investigation of load-independent variables of ventricular performance. Uni-ventricular evaluation is often performed in preclinical research. However, the right and left ventricles exert functional interdependence due to their parallel and serial connections, encouraging simultaneous evaluation of both ventricles. Furthermore, various pharmacological interventions may affect the ventricles and their preloads and afterloads differently. 
We describe our closed chest approach to admittance-based bi-ventricular PV loop recordings in a porcine model of acute right ventricular (RV) overload. We utilize minimally invasive techniques with all vascular accesses guided by ultrasound. PV catheters are positioned, under fluoroscopic guidance, to avoid thoracotomy in animals, as the closed chest approach maintains the relevant cardiopulmonary physiology. The admittance technology provides real-time PV loop recordings without the need for post-hoc processing. Furthermore, we explain some essential troubleshooting steps during critical timepoints of the presented procedure. 
The presented protocol is a reproducible and physiologically relevant approach to obtain a bi-ventricular cardiac PV loop recording in a large animal model. This can be applied to a large variety of cardiovascular animal research.

The present instructions describe an approach to achieve admittance-based PV recordings from both the RV and the LV in a large animal.
To compare our simultaneous PV recordings in the RV and LV, we performed a linear regression of the bi-ventricular CO measurements from our largest study18 with the highest number of simultaneous RV CO and LV CO measurements (n=379 recordings from 12 animals). We found that the slope was 1.03 (95%CI 0.90-1.15) with a Y-intercept of 695 (...

Watch this Scientific Journal Video about Closed Chest Biventricular Pressure-Volume Loop Recordings with Admittance Catheters in a Porcine Model at JoVE.com

Closed Chest Biventricular Pressure-Volume Loop Recordings with Admittance Catheters in a Porcine Model

Here we present a closed chest approach to admittance-based bi-ventricular pressure-volume loop recordings in pigs with acute right ventricular dysfunction.

Pressure-volume (PV) loop recording enables the state-of-the-art investigation of load-independent variables of ventricular performance. Uni-ventricular ...

This closed chest approach to obtain biventricular pressure-volume loop recordings enables state-of-the-art hemodynamic evaluation in an en vivo porcine model. The main advantage of this minimally invasive method is that it allows for thorough and load-independent evaluation of the cardiovascular system while maintaining near-intact thoracic physiology. This method of biventricular evaluation is very important for most experimental cardiovascular models because the left and the right heart may act differently, for instance, on pharmacological stimulation.And at the same time, there can be interdependency between the left and the right heart, so it's very important to assess both cardiac ventricles at the same time. After anesthetization, use a 17 gauge sterile venous catheter to puncture the skin. Guide the needle to intravascular positioning with the help of the ultrasound.Use the Seldinger technique to replace the needle with a guide wire. Remove the venous catheter and leave only the guide wire in the intravascular lumen. To ease the insertion of the sheath, make a small skin incision adherent to the guide wire.Then place an appropriately-sized sheath over the guide wire and into the vessel of choice using the Seldinger technique. Insert the Swan-Ganz catheter in the right jugular vein through the eight French sheath. Use thoracoscopy to observe when the distal part of the Swan-Ganz catheter is out of the sheath by resistance-free inflation of the balloon.Slowly advance the Swan-Ganz catheter. Observe the changes in the pressure signal from the distal port as it enters the right ventricle and shortly after the distal port passes through the pulmonary artery. Deflate the balloon and ensure that the distal pressure port is still in the main pulmonary artery using thoracoscopy and the pressure signal.Insert a long guide wire through the seven French sheath in the left jugular vein, then advance the guide wire through the upper central veins, the right atrium, and the inferior vena cava, monitoring the movements using thoracoscopy. Leaving the guide wire in the venous circulation, extract the seven French sheath and compress the entry point to avoid bleeding. Then use the Seldinger technique to exchange the seven French sheath for the 16 French sheath.Advance the 16 French sheath over the guide wire until the tip of the sheath has reached the level of the superior vena cava. Insert the pressure volume catheter in the 16 French sheath, then advance it into the right atrium. Point the external end of the 16 French sheath downwards and medially, which will point the internal end of the sheath anteriorly.Advance the pressure volume catheter from the right atrium into the more anteriorly positioned right ventricle. Verify this by the change in pressure signal from the pressure volume catheter to a classic ventricular shape and by the tactile resistance as the pressure volume catheter meets the right ventricular apex. Finally, to avoid any hemodynamic or electrical influence of the device located close to the heart, retract the 16 French sheath outside the thoracic cavity once the catheter is in the right ventricle.Insert the pressure-volume catheter in the eight French sheath into the left carotid artery. Advance the pressure volume catheter through the eight French sheath towards the aortic valves guided by fluoroscopy. To advance the pressure volume catheter through the open aortic valves, synchronize the quick advancement of the pressure-volume catheter to a systolic phase of the cardiac cycle.Verify the success by observing a change in the pressure signal from the PV catheter to a classic ventricular shape. Advance the guide wire from the femoral vein to the inferior vena cava at the diaphragm level, then insert the balloon over the guide wire advancing it to the diaphragm level at the end expiration. Check that the optimal phase and magnitude signals are received from both ventricles.Ensure both ventricular pressure-volume loops have the proper shape, realistic pressures and volumes. Record pressure-volume loops over 30 to 60 seconds of continuous ventilation and use the average value of all respiratory cycles to perform analysis. For load-independent pressure-volume variables, do a breath hold.Wait for a few heartbeats and then slowly inflate the inferior vena cava balloon with the chosen liquid. Observe as the right ventricular pressure-volume loops become progressively smaller and shift leftward. Keep the inferior vena cava balloon inflated long enough to reduce right ventricular output and thereby the left ventricle preload and observe the progressive decrease in the left ventricular pressure and volume.Acceptable pressure-volume loops obtained from the left ventricle should have a classic square shape, and those from the right ventricles should have the classic triangular shape. The pressure-volume catheters need to be adjusted to improve the quality of loops if suboptimal loops are obtained from the left or the right ventricle. It is more difficult to obtain the classic triangular loops from the right ventricle and some static noise due to blood turbulence in the end diastole is acceptable.The two ventricles are serially connected, causing a time-wise shift in preload reduction as the inferior vena cava balloon quickly reduces right ventricular preload, but left ventricular preload is not reduced until the right ventricular output has decreased by its lack of preload. A gradual reduction in the preload causes a family of loops with a gradual reduction in volume and pressure to both the left ventricle and right ventricle. Insertion of the right-sided pressure-volume catheter can be difficult, but with practice, anyone can learn it.Importantly, necessary time must be spent optimizing catheter positioning to obtain reliable data. This method can thoroughly evaluate cardiovascular animal models and the effects of interventions. The hemodynamic investigations may be supplemented by imaging and blood samples to mimic clinical workup.

closed-chest-biventricular-pressure-volume-loop-recordings-with

Research

JoVE Journal

Medicine

3.4K Views.  Aarhus University Hospital. This closed chest approach to obtain biventricular pressure-volume loop recordings enables state-of-the-art hemodynamic evaluation in an en vivo porcine model. The main advantage of this minimally invasive method is that it allows for thorough and load-independent evaluation of the cardiovascular system while maintaining near-intact thoracic physiology. This method of biventricular evaluation is very important for most experimental cardiovascular models because the left and the right heart ma...