This work was supported by the Sichuan Provincial Major R&#38;D Project (2022YFS043) and the Chengdu University of Traditional Chinese Medicine Youth Foundation Advancement Talent Special Project (QJJJ2022029).

The animal protocol was reviewed and approved by the Chengdu University of Traditional Chinese Medicine Experimental Animal Welfare Ethics Committee (Record No. 2023-04). Male Sprague Dawley (SD) rats (280 &#177; 20 g, 8-10 weeks old) were used for the present study. The rats were kept in an animal chamber and were free to drink and eat.
1. Solution preparation
<ol>
	<li>Prepare 0.9% NaCl solution to be used to keep the work area adequately moist.</li>
	<li>To prepare 20% hypertonic NaCl solution, dissolve 2 g of NaCl in 10 mL of double distilled water (ddH2O). In order to determine the parallel conductivity of the myocardium, it is necessary to alter the conductivity of the intraventricular liquid.</li>
	<li>Prepare 1% enzyme-active powdered detergent solution. Use this at the completion of the experiment, to immerse the pressure-volume electrical catheter in the solution for 1-2 h.</li>
	<li>Prepare FA solution by dissolving 10 mg of ferulic acid in 20 mL of ddH2O. Filter the solution through a 0.22 &#181;m membrane. Inject the rat with 1 mL/kg ferulic acid solution.</li>
</ol>
2. Preparation of the sensor
<ol>
	<li>Immerse the pressure-volume sensor in 0.9% NaCl solution at 37 &#176;C for about 30-60 min before the start of the experiment, which facilitates the stability of the experimental data.</li>
	<li>Connect the experimental apparatus. The system for measuring pressure-volume loops consists of a pressure-volume catheter, two control units, a recording unit, and computer running software. The pressure-volume loop module in the software will provide a reference experimental procedure.</li>
	<li>Press the Start button and the software will automatically record the monitoring data from the pressure-volume sensor.</li>
	<li>Use the Miro-Tip Pressure Volume (MPVS) software to calibrate the pressure and conductivity.</li>
</ol>
3. Pre-experimental rat preparation
<ol>
	<li>Administer ketamine (50 mg/kg) and fentanyl (0.25 mg/kg) to the rats via intramuscular injection5.</li>
	<li>Pinch the toes of the rats to verify anesthetic depth by an absence of reflexes. Emotion affects the physiology state of rats and pain causes alterations in cardiac function16. Use small animal shavers and depilatory creams to remove hair on surgical sites. Use iodophor and 75% alcohol to wipe the skin to maintain sterility.</li>
	<li>Immobilize fully anesthetized rats on an isothermal heating plate with the back in contact with the heating plate.</li>
	<li>Insert a temperature probe coated with petroleum jelly into the rectum of the rat. Maintain the rat body temperature at 37 &#176;C &#177; 0.5 by adjusting the heating plate. 
	NOTE: It is necessary to keep the airway unobstructed during the experiment.</li>
</ol>
4. Catheter insertion into the right carotid artery
<ol>
	<li>Incise the skin on the right side of the median line of the neck of rats, longitudinally. Make a 4 cm incision and separate muscle and connective tissue by forceps. The carotid artery situated on the right side of the trachea is visible. The right carotid artery of the rat is dark red, strongly pulsating, and has a white vagus nerve parallel to it.</li>
	<li>Separate the carotid artery from other tissues and nerves using forceps. Place three 5-0 surgical lines below the clean carotid artery. Drip sterile 0.9% sodium chloride solution onto the surgical area to maintain the moistening of the carotid artery.</li>
	<li>Cut&#160;the skin above the left clavicle and peel off the tissue around the jugular vein. Then, place a 5-0 surgical thread under the left jugular vein.</li>
	<li>Use arterial clips to suspend blood flow proximally, using micro scissors to cut a section in the vessel where blood flow has stopped. It is normal for a small amount of blood to appear in the wound cross-section. If blood is exiting the vessel rapidly and intermittently, lift the proximal surgical line and apply the arterial clamp again.</li>
	<li>Insert the catheter from the cross-section along the carotid artery deep into the left ventricle. Ensure the lowest systolic pressure value after entering the left ventricle is close to 0 mmHg.</li>
	<li>To obtain a reasonable pressure-volume relationship, slightly adjust the pressure-volume catheter in the ventricular chamber. To prevent massive blood loss and the catheter from changing position due to heartbeat, ligate the proximal end of the surgical line. 
	NOTE: The body temperature, anesthesia level, pressure signal, and conductance signal of the rat should remain stable during this process. The respiratory tract of the rat should be kept open.</li>
</ol>
5. Drug injection and conductivity calibration
<ol>
	<li>Maintain the position of the pressure volume catheter in the ventricular chamber, after the data stabilizes, ligate the surgical line distal to the jugular vein ligated and slowly inject upto 1 mL/kg of ferulic acid solution. Observe for 5-10 min.</li>
	<li>Inject 50 &#181;L of 20% NaCl solution from the left jugular vein to remove the parallel conductance generated by the myocardium. The volume range of the parallel conductance was approximately 130-280 &#181;L5. Repeat this 3x at an interval of 2 min.</li>
	<li>After ventricular pressure and volume testing in rats, take blood from the rat&#39;s abdominal aorta using a blood collection needle. Place the collected blood in a sodium heparin collection tube and invert up and down 2x to prevent blood clotting. Euthanize the experimental rats by&#160;injecting 120 mg/kg of pentobarbital sodium through the left jugular vein.</li>
	<li>Perform conversion of measured conductance to actual blood volume using rat volume calibration tubes. Place blood mixed with sodium heparin, sequentially, into the orifices of the calibration tube, and the catheter detects the conductance values of the blood in the different orifices and records them in the pressure-volume monitoring module.</li>
</ol>
6. Data analysis
<ol>
	<li>By adding the measured conductivity value of a known volume of blood to the specified location, the software automatically plots the curve and extrapolates the conductivity of the blood. Use at least three sets of blood conductivity values to deduce the blood conductivity of the rat under test. The blood conductivity is individualized. For each rat under the test, perform this procedure individually.</li>
	<li>Hypertonic calibration: By adding the data obtained from three injections of hypertonic saline to a specified location, the software calculates parallel conductance averages and automatically calibrates the experimental data.</li>
	<li>Utilize regions with stable blood pressure and conductance values to analyze the left ventricular function of rats.</li>
	<li>Click on Analyze and the software will automatically calculate a variety of parameters based on the selected area, including EF (left ventricular ejection fractions) SW (stroke work), and CO (cardiac output), etc.</li>
</ol>

Monitoring Cardiac Function of Rats Using the Pressure-Volume Conductance Technique

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The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

It is essential to adopt a rational dosing strategy for different states of cardiac function. The pressure-volume conductance catheter technique is the most intuitive way to study left ventricular function5. This method enables the effects of drugs on cardiac function to be studied from a whole perspective. We describe the various stages of the experiment in detail. This will provide some facility for the study of heart function.
The pressure volume conductivity cathete...

Cardiovascular disease has the highest mortality rate in the world1. Its causes include coronary artery stenosis (myocardial ischemia), coronary artery blockage (myocardial infarction), and ischemia-reperfusion injury2. As the heart is in a constant systolic and diastolic cycle, it is one of the most energy-demanding parts of the body. Therefore, when the coronary arteries have difficulty maintaining sufficient energy and oxygen, cardiac function inevitably decreases, which has a negative impact on other organs3,4. The heart is a powerhouse in the circulatory system, and cardiac function needs to be assessed rationally.
Assessment of cardiac function by ventricular pressure and volume relationships is considered to be a comprehensive method5. Real-time changes in ventricular pressure and volume during the complete cardiac cycle make up the pressure-volume loop. The ventricular pressure-volume loop allows quantitative analysis of cardiac function and reserve capacity in terms of different phases and energies of the ventricle. The normal ventricle has a small end-systolic volume with good beat work and efficiency5,6,7.
The pressure-volume conduction catheter technique is an invasive method for detecting the status of the left ventricle. It can be used to obtain a continuous real-time pressure-volume loop8. Pressure volumetric conductivity catheters are powerful tools, and sound handling procedures are essential for reproducible and reliable results, including in vivo analysis of myocardial parallel conductivity during saline calibration and in vitro measurement of blood conductivity in cuvette calibration3.
Ferulic acid (FA), a phenolic acid, is widely distributed in plant kingdoms such as Avena sativa and Ligusticum chuanxiong hort9,10. Ferulic acid has pharmacological effects of lowering blood pressure and arrhythmia. FA is a bioactive natural product with multiple functions. FA can resist oxidative damage, reduce inflammatory responses, inhibit platelet aggregation, and prevent coronary heart disease and atherosclerosis11. However, most studies on ferulic acid have focused on one aspect of the heart and rarely have the effects of ferulic acid been evaluated in the circulatory system12,13,14,15. Here we describe a closed-chest approach to isoflurane anesthesia combined with Ketamine (50 mg/kg) with a focus on the cardiac response to ferulic acid solution during jugular vein injection.
We will describe the complete procedure for using the tool under closed-chest conditions, including solution preparation, preparation of the transducer, pre-experimental rat preparation, catheter insertion into the right carotid artery and data analysis. The duration of the experiment is usually less than 4 h and it is determined by the different experimental protocols. In a single experiment, we can obtain detailed cardiac information such as left ventricular pressure, volume, and heart rate.

<table><tbody><tr><td>1 mL syringe</td><td>Sartorius AG, Germany</td><td>-</td><td></td></tr><tr><td>Animal temperature maintainer</td><td>Rayward Life Technology Co., Ltd</td><td>69020</td><td></td></tr><tr><td>Dual Bio Amp</td><td>Millar, Inc., USA</td><td>DA-100</td><td></td></tr><tr><td>Enzyme-Active Powdered Detergent</td><td>Alconox Inc., USA</td><td>1104</td><td></td></tr><tr><td>Ferulic acid</td><td>&amp;nbsp;Macklin Biochemical Co., Ltd,Shanghai, China</td><td>F900027</td><td></td></tr><tr><td>Mikro-Tip Catheter Transducers, SPR-838NR</td><td>Millar, Inc., USA</td><td>SPR-838NR</td><td></td></tr><tr><td>Millar Miro-Tip Pressure Volume (MPVS) Ultra</td><td>Millar, Inc., USA</td><td>SPR-869</td><td></td></tr><tr><td>Pet electric clippers</td><td>Jinyun County New Concept Home Supplies Co., Ltd.</td><td>&amp;nbsp;-</td><td></td></tr><tr><td>Power Lab 8 / 35</td><td>Millar, Inc., USA</td><td>PL3508</td><td></td></tr><tr><td>Sodium Chloride, NaCl</td><td>&amp;nbsp;Kelong Chemical Reagent, Chengdu, China</td><td>KX829463</td><td></td></tr><tr><td>Veet hair removal cream</td><td>Shanghai Songqi E-commerce Co., Ltd.</td><td>3226470</td><td></td></tr></tbody></table>

real-time detection of ferulic acid effects on rat left ventricle using pressure-volume conductivity catheter

Decreased cardiac function can have a negative impact on other organs. The left ventricular pressure-volume relationship is considered to be a valid method for evaluating cardiac function. Real-time monitoring of cardiac function is important for drug evaluation. Under closed-chest conditions, the miniature transducer, which is an important component of the pressure-volume catheter, enters the left ventricle of the rat through the right carotid artery. The device visualizes the changes in cardiac function during the experiment in the form of a pressure-volume loop. The actual volume of the ventricle is calculated by altering the conductivity of the blood by injecting 50 &#181;L of a 20% sodium chloride solution into the rat's left jugular vein. The actual volume of the rat's ventricular cavity is calculated by measuring the conductivity of the blood in a known volume using a pressure-volume conductance catheter. This protocol allows for continuous observation of the effects of drugs on the heart and will promote the rationale for the use of specialty ethnic drugs in cardiovascular disease.

Each test (n = 3) was predicated on the entry of a pressure-volume conductivity catheter into the left ventricle. There are significant signal changes, such as a marked increase in the range of pressure, as the catheter enters the left ventricle from the carotid artery (Figure 1). Graphical analysis of the pressure-volume relationship is completed by plotting the volume (&#181;L) on the Y-axis and the pressure (mmHg) on the X-axis. Rat left ventricular pressure was within 10-105 mmHg, and co...

Watch this Scientific Journal Video about Author Spotlight: Advantages of Pressure-Volume Loop Measurement Method in Cardiovascular Research at JoVE.com

Author Spotlight: Advantages of Pressure-Volume Loop Measurement Method in Cardiovascular Research

This protocol describes a method for measuring left ventricular pressure and volume using the pressure-volume conductance technique. This method enables continuous real-time monitoring of the effects of drugs on the heart.

Real-Time Detection of Ferulic Acid Effects on Rat Left Ventricle Using Pressure-Volume Conductivity Catheter

Decreased cardiac function can have a negative impact on other organs. The left ventricular pressure-volume relationship is considered to be a valid ...

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403 Views.  Chengdu University of Traditional Chinese Medicine. This protocol describes a method for measuring left ventricular pressure and volume using the pressure-volume conductance technique. This method enables continuous real-time monitoring of the effects of drugs on the heart.

Video: Author Spotlight: Advantages of Pressure-Volume Loop Measurement Method in Cardiovascular Research

Permanent Ligation of the Left Anterior Descending Coronary Artery in Mice: A Model of Post-myocardial Infarction Remodelling and Heart Failure

Heart failure is a syndrome in which the heart fails to pump blood at a rate commensurate with cellular oxygen requirements at rest or during stress. It is characterized by fluid retention, shortness of breath, and fatigue, in particular on exertion. Heart failure is a growing public health problem, the leading cause of hospitalization, and a major cause of mortality. Ischemic heart disease is the main cause of heart failure.
Ventricular remodelling refers to changes in structure, size, and shape of the left ventricle. This architectural remodelling of the left ventricle is induced by injury (e.g., myocardial infarction), by pressure overload (e.g., systemic arterial hypertension or aortic stenosis), or by volume overload. Since ventricular remodelling affects wall stress, it has a profound impact on cardiac function and on the development of heart failure. A model of permanent ligation of the left anterior descending coronary artery in mice is used to investigate ventricular remodelling and cardiac function post-myocardial infarction. This model is fundamentally different in terms of objectives and pathophysiological relevance compared to the model of transient ligation of the left anterior descending coronary artery. In this latter model of ischemia/reperfusion injury, the initial extent of the infarct may be modulated by factors that affect myocardial salvage following reperfusion. In contrast, the infarct area at 24 hr after permanent ligation of the left anterior descending coronary artery is fixed. Cardiac function in this model will be affected by 1) the process of infarct expansion, infarct healing, and scar formation; and 2) the concomitant development of left ventricular dilatation, cardiac hypertrophy, and ventricular remodelling.
Besides the model of permanent ligation of the left anterior descending coronary artery, the technique of invasive hemodynamic measurements in mice is presented in detail.

Heart failure is the leading cause of hospitalization and a major cause of mortality. A model of permanent ligation of the left anterior descending coronary artery in mice is applied to investigate ventricular remodelling and cardiac dysfunction post-myocardial infarction. The technique of invasive hemodynamic measurements in mice is presented.

Heart failure is a syndrome in which the heart fails to pump blood at a rate commensurate with cellular oxygen requirements at rest or during stress. It ...

Cardiac Catheterization in Mice to Measure the Pressure Volume Relationship: Investigating the Bowditch Effect

Animal models that mimic human cardiac disorders have been created to test potential therapeutic strategies. A key component to evaluating these strategies is to examine their effects on heart function. There are several techniques to measure in vivo cardiac mechanics (e.g., echocardiography, pressure/volume relations, etc.). Compared to echocardiography, real-time left ventricular (LV) pressure/volume analysis via catheterization is more precise and insightful in assessing LV function. Additionally, LV pressure/volume analysis provides the ability to instantaneously record changes during manipulations of contractility (e.g., &#946;-adrenergic stimulation) and pathological insults (e.g., ischemia/reperfusion injury). In addition to the maximum (+dP/dt) and minimum (-dP/dt) rate of pressure change in the LV, an accurate assessment of LV function via several load-independent indexes (e.g., end systolic pressure volume relationship and preload recruitable stroke work) can be attained. Heart rate has a significant effect on LV contractility such that an increase in the heart rate is the primary mechanism to increase cardiac output (i.e., Bowditch effect). Thus, when comparing hemodynamics between experimental groups, it is necessary to have similar heart rates. Furthermore, a hallmark of many cardiomyopathy models is a decrease in contractile reserve (i.e., decreased Bowditch effect). Consequently, vital information can be obtained by determining the effects of increasing heart rate on contractility. Our and others data has demonstrated that the neuronal nitric oxide synthase (NOS1) knockout mouse has decreased contractility. Here we describe the procedure of measuring LV pressure/volume with increasing heart rates using the NOS1 knockout mouse model.

This article describes the measurement of murine left ventricular function via pressure/volume analysis at different heart rates.

Animal models that mimic human cardiac disorders have been created to test potential therapeutic strategies. A key component to evaluating these ...

Real-time Pressure-volume Analysis of Acute Myocardial Infarction in Mice

Acute myocardial infarction can lead to acute heart failure and cardiogenic shock. The evaluation of hemodynamics is critical for the evaluation of any potential therapeutic approach directed against acute left ventricular (LV) dysfunction. Current imaging modalities (e.g., echocardiography and magnetic resonance imaging) have several limitations since data on LV pressure cannot directly be measured. LV catheterization in mice undergoing coronary artery occlusion could serve as a novel method for a real-time evaluation of LV function.
At the beginning of the procedure, mice were anesthetized followed by endotracheal intubation. For LV catheterization, the right carotid artery was exposed via middle-neck incision. The catheter was introduced and placed into the LV cavity. Left thoracotomy was conducted and the left main coronary artery (LCA) was ligated. To induce reperfusion, the suture was released after 45 min. Pressure-volume data was recorded at all times.
Ligation of the LCA caused a decrease in LV systolic function as evidenced by a 30% reduction in stroke volume, LV ejection fraction (EF), and cardiac output. Maximum dP/dt as a parameter for LV contractility was also significantly reduced and diastolic function was severely impaired (minimum dP/dt -40%). Reperfusion over a period of 20 min did not lead to a complete recovery of LV function.
Real-time pressure-volume analysis served as a valid procedure for monitoring cardiac function during acute myocardial infarction in mice. Maintaining stable anesthesia and a standardized surgical approach was crucial to ensure valid results. As the early phase of acute myocardial infarction is critical for morbidity and mortality, the delineated method could be beneficial for preclinical evaluation of new strategies for cardioprotection.

Acute myocardial infarction in mice induces acute but incompletely characterized changes in left ventricular (LV) function. LV catheterization in mice undergoing coronary artery occlusion serves as a novel method for a real-time evaluation of LV function.

Acute myocardial infarction can lead to acute heart failure and cardiogenic shock. The evaluation of hemodynamics is critical for the evaluation of any ...

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. ...

Semi-Minimal Invasive Method to Induce Myocardial Infarction in Rats and the Assessment of Cardiac Function by an Isolated Working Heart System

Myocardial infarction (MI) remains the main contributor to morbidity and mortality worldwide. Therefore, research on this topic is mandatory. An easily and highly reproducible MI induction procedure is required to obtain further insight and better understanding of the underlying pathological changes. This procedure can also be used to evaluate the effects or potency of new and promising treatments (as drugs or interventions) in acute MI, subsequent remodeling and heart failure (HF). After intubation and pre-operative preparation of the animal, an anesthetic protocol with isoflurane was performed, and the surgical procedure was conducted&#160;quickly. Using a minimally invasive approach, the left anterior descending artery (LAD) was located and occluded by a ligature. The occlusion can be performed acutely for subsequent reperfusion (ischemia/reperfusion injury). Alternatively, the vessel can be ligated permanently to investigate the development of chronic MI, remodeling or HF. Despite common pitfalls, the drop-out rates are minimal. Various treatments such as remote ischemic conditioning can be examined for their cardioprotective potential pre-, peri- and post-operatively. The post-operative recovery was quick as the anesthesia was precisely controlled and the duration of the operation was short. Post-operative analgesia was administered for three days. The minimally invasive procedure reduces the risk of infection and inflammation. Furthermore, it facilitates rapid recovery. The &#8220;working heart&#8221; measurements were performed ex vivo and enabled precise control of preload, afterload and flow. This procedure requires specific equipment and training for adequate performance. This manuscript provides a detailed step-by-step introduction for conducting these measurements.

This article presents an efficient method to perform myocardial ischemia and subsequent chronic reperfusion in rats using a minimally invasive approach. In addition, left ventricular hemodynamic function of rats is assessed by echocardiography and isolated working heart methods.&#160;

Myocardial infarction (MI) remains the main contributor to morbidity and mortality worldwide. Therefore, research on this topic is mandatory. An easily ...

Biventricular Assessment of Cardiac Function and Pressure-Volume Loops by Closed-Chest Catheterization in Mice

Assessment of cardiac function is essential to conduct cardiovascular and pulmonary-vascular preclinical research. Pressure-volume loops (PV loops) generated by recording both pressure and volume during cardiac catheterization are vital when assessing both systolic and diastolic cardiac function. Left and right heart function are closely related, reflected in ventricular interdependence. Thus, recording biventricular function in the same animal is important to get a complete assessment of cardiac function. In this protocol, a closed chest approach to cardiac catheterization consistent with the way catheterization is performed in patients is adopted in mice. While challenging, the closed chest strategy is a more physiological approach, because opening the chest results in major changes in preload and afterload that create artifacts, most notably a fall in systemic blood pressure. While high-resolution echocardiography is used to assess rodents, cardiac catheterization is invaluable, particularly when assessing diastolic pressures in both ventricles.
Described here is a procedure to perform invasive, closed chest, sequential left and right ventricular pressure-volume (PV) loops in the same animal. PV loops are acquired using&#160;admittance technology with a mouse pressure-volume catheter and pressure-volume system acquisition. The procedure is described, beginning with the neck dissection, which is required to access the right jugular vein and the right carotid artery, to the insertion and positioning of the catheter, and finally the data acquisition. Then, the criteria required to ensure the acquisition of high-quality PV loops are discussed. Finally, the analysis of the left and right ventricular PV loops and the different hemodynamic parameters available to quantify systolic and diastolic ventricular function are briefly described.

Presented here is a protocol to assess biventricular heart function in mice by generating pressure-volume (PV) loops from the right and left ventricle in the same animal using closed chest catheterization. The focus is on the technical aspect of surgery and data acquisition.

Assessment of cardiac function is essential to conduct cardiovascular and pulmonary-vascular preclinical research. Pressure-volume loops (PV loops) ...

Cardiac Response to &#946;-Adrenergic Stimulation Determined by Pressure-Volume Loop Analysis

Determination of the cardiac function is a robust endpoint analysis in animal models of cardiovascular diseases in order to characterize effects of specific treatments on the heart. Due to the feasibility of genetic manipulations the mouse has become the most common mammalian animal model to study cardiac function and to search for new potential therapeutic targets. Here we describe a protocol to determine cardiac function&#160;in vivo using pressure-volume loop measurements and analysis during basal conditions and under &#946;-adrenergic stimulation by intravenous infusion of increasing concentrations of isoproterenol. We provide a refined protocol including ventilation support taking into account the positive end-expiratory pressure to ameliorate negative effects during open-chest measurements, and potent analgesia (Buprenorphine) to avoid uncontrollable myocardial stress evoked by pain during the procedure. All together the detailed description of the procedure and discussion about possible pitfalls enables highly standardized and reproducible pressure-volume loop analysis, reducing the exclusion of animals from the experimental cohort by preventing possible methodological bias.

Here we describe a cardiac pressure-volume loop analysis under increasing doses of intravenously infused isoproterenol to determine the intrinsic cardiac function and the &#946;-adrenergic reserve in mice. We use a modified open-chest approach for the pressure-volume loop measurements, in which we include ventilation with positive end-expiratory pressure.

Determination of the cardiac function is a robust endpoint analysis in animal models of cardiovascular diseases in order to characterize effects of ...

Cardiac Pressure-Volume Loop Analysis Using Conductance Catheters in Mice

Cardiac pressure-volume loop analysis is the &#8220;gold-standard&#8221; in the assessment of load-dependent and load-independent measures of ventricular systolic and diastolic function. Measures of ventricular contractility and compliance are obtained through examination of cardiac response to changes in afterload and preload. These techniques were originally developed nearly three decades ago to measure cardiac function in large mammals and humans. The application of these analyses to small mammals, such as mice, has been accomplished through the optimization of microsurgical techniques and creation of conductance catheters. Conductance catheters allow for estimation of the blood pool by exploiting the relationship between electrical conductance and volume. When properly performed, these techniques allow for testing of cardiac function in genetic mutant mouse models or in drug treatment studies. The accuracy and precision of these studies are dependent on careful attention to the calibration of instruments, systematic conduct of hemodynamic measurements and data analyses. We will review the methods of conducting pressure-volume loop experiments using a conductance catheter in mice.

Cardiac pressure-volume loop analysis is the most comprehensive way to measure cardiac function in the intact heart. We describe a technique to perform and analyze cardiac pressure volume loops, using conductance catheters.

Cardiac pressure-volume loop analysis is the &#8220;gold-standard&#8221; in the assessment of load-dependent and load-independent measures of ventricular ...

Biology

Measuring Pressure Volume Loops in the Mouse

Understanding the causes and progression of heart disease presents a significant challenge to the biomedical community. The genetic flexibility of the mouse provides great potential to explore cardiac function at the molecular level. The mouse&#39;s small size does present some challenges in regards to performing detailed cardiac phenotyping. Miniaturization and other advancements in technology have made many methods of cardiac assessment possible in the mouse. Of these, the simultaneous collection of pressure and volume data provides a detailed picture of cardiac function that is not available through any other modality. Here a detailed procedure for the collection of pressure-volume loop data is described. Included is a discussion of the principles underlying the measurements and the potential sources of error. Anesthetic management and surgical approaches are discussed in great detail as they are both critical to obtaining high quality hemodynamic measurements. The principles of hemodynamic protocol development and relevant aspects of data analysis are also addressed.

This manuscript describes a detailed protocol for the collection of pressure-volume data from the mouse.

Understanding the causes and progression of heart disease presents a significant challenge to the biomedical community. The genetic flexibility of the ...

Functional Assessment of the Donor Heart During Ex Situ Perfusion: Insights from Pressure-Volume Loops and Surface Echocardiography

Heart transplantation remains the gold standard treatment for advanced heart failure. However, the current critical organ shortage has resulted in the allocation of a growing number of donor hearts with extended criteria. These marginal grafts are associated with a high risk of primary graft failure and may benefit from ex situ perfusion before transplant. This technology allows for extended organ preservation using warm oxygenated blood perfusion with continuous metabolic monitoring. The only NESP device currently available for clinical practice perfuses the organ in an unloaded non-working state, which does not allow for functional assessment of the beating heart. We therefore developed an original platform of NESP in working mode conditions with adjustment of left ventricular preload and afterload. This protocol was applied in porcine hearts. Ex situ functional assessment of the heart was achieved with intracardiac conductance catheterization and surface echocardiography. Along with a description of the experimental protocol, we herein report the main results, as well as pearls and pitfalls associated with the acquisition of pressure-volume loops and myocardial power during NESP. Correlations between hemodynamic findings and ultrasound variables are of major interest, especially for further rehabilitation of donor hearts before transplantation. This protocol aims to improve the assessment of donor hearts to both increase the donor pool and reduce the incidence of primary graft failure.

Functional Assessment of the Donor Heart During Ex Situ Perfusion: Insights from Pressure-Volume Loops and Surface Echocardiography

A reliable noninvasive approach for functional assessment of the donor heart during normothermic ex situ heart perfusion (NESP) is lacking. We herein describe a protocol for ex situ assessment of myocardial performance using the epicardial echocardiography and conductance catheter method.

Heart transplantation remains the gold standard treatment for advanced heart failure. However, the current critical organ shortage has resulted in the ...

Real-Time Detection of Ferulic Acid Effects on Rat Left Ventricle Using Pressure-Volume Conductivity Catheter

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Chapters in this video

Permanent Ligation of the Left Anterior Descending Coronary Artery in Mice: A Model of Post-myocardial Infarction Remodelling and Heart Failure

Cardiac Catheterization in Mice to Measure the Pressure Volume Relationship: Investigating the Bowditch Effect

Real-time Pressure-volume Analysis of Acute Myocardial Infarction in Mice

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

Semi-Minimal Invasive Method to Induce Myocardial Infarction in Rats and the Assessment of Cardiac Function by an Isolated Working Heart System

Biventricular Assessment of Cardiac Function and Pressure-Volume Loops by Closed-Chest Catheterization in Mice

Cardiac Response to β-Adrenergic Stimulation Determined by Pressure-Volume Loop Analysis

Cardiac Pressure-Volume Loop Analysis Using Conductance Catheters in Mice

Measuring Pressure Volume Loops in the Mouse

Functional Assessment of the Donor Heart During Ex Situ Perfusion: Insights from Pressure-Volume Loops and Surface Echocardiography