Function/ Services of the CORE:
The Organ Function CORE will provide the expertise and has already assembled, state of the art equipment for assessing cardiac function using a Visualsonics Vevo 2100 ultrasound imaging system for rodent echocardiograms, and a MPVS Ultra® pressure-volume system for simultaneous high-fidelity intracardiac pressure-volume analysis, as well as lung function using a flexiVent® system platform for measuring respiratory mechanics.
Echocardiography is a form of non-invasive assessment for performing serial evaluations of cardiac function or real-time monitoring during and after pharmacological or therapeutic intervention. Echocardiography has the versatility that allows for rapid and comprehensive evaluation of myocardial function, valvular and vascular structure in animal models. Protocols are adapted to the needs of the Investigator.
Echocardiograms can be performed on mice and rats using a Visualsonics Vevo 2100 high resolution ultrasound machine with linear array MicroscanTM Transducers (MS250, 13-24 MHz) after general anesthesia with isolflurane to perform 2D Doppler, tissue-Doppler and M-mode recordings.
Comprehensive small animal echocardiogram includes:
· 2D short- and long-axis cine loops of the heart from the parasternal view
· 2D guided M-mode image of the left ventricle
· Doppler recordings of the trans-mitral and aortic valve velocities from the apical view
· Doppler tissue recordings of the mitral annular and left ventricular segmental wall motion velocities.
Screening Echocardiogram: Non-invasive single transthoracic cardiac ultrasound exam performed under anesthesia that includes 2D and M-mode images of the left ventricle and Doppler recordings of trans-valvular flow indices.
Examples of Normal Left Ventricle Function
Data provided at the study end: Spreadsheet with various echo parameters including:
· LV Fractional Shortening
· LV Ejection Fraction
· LV Volumes
· LV Stroke Volume
· Septal Thickness in Diastole
· Posterior Wall Thickness in Diastole
· LV Dimensions in Diastole and Systole
· LV Mass
· Right Ventricular Outflow Tract (RVOT)
· Cardiac output
· Tricuspid annular plane systolic excursion (TAPSE)
· Transmitral and transtricuspid E and A velocities
This system includes a computer and a novel software-controlled ventilator for mice designed to generate accurate and detailed measurements of respiratory mechanics. With this system, resistance and compliance measurements and pressure-volume loops can be obtained.
The flexiVent is a versatile and precise programmable ventilator for laboratory animals.
With improved piston positioning accuracy and a completely redesigned valve configuration, the flexiVent FX is not only completely quiet, but also enables enhanced control of the expiratory waveform, permitting a wider range of ventilator modes and features.
Automatic PEEP control is available as an alternative to the traditional water trap.
The pressure, volume and flow waveforms as well as any additional channels for vital signs monitoring are continuously recorded to maintain a seamless record of the subject throughout the experimentation session.
There are many parameters that can be measured using this system and they are listed in the service request form which is available on the CORE website.
CARDIAC IN VIVO HEMODYNAMIC MEASUREMENTS
The market-leading Millar Pressure-Volume (PV) Loop System (MPVS) simultaneously and continuously measures high-fidelity ventricular pressure and volume from the intact beating hearts of animals ranging in size from transgenic mice to livestock. The MPVS measures high fidelity pressure, volume and intracardiac ECG via a single catheter, which combines a Millar pressure sensor with four to twelve conductance electrodes. The cardiovascular pressure and volume signals can be plotted against each other in real time, generating the characteristic left or right ventricular PV loops. These are an excellent representation of the cardiac cycle and yield key information regarding normal or diseased conditions of the heart.
· Elastance (EDPVR)
· Cardiac Output
· Stroke Volume
· Max and Min Ventricular dP/dt
· Pre-load Recruitable Stroke Work (PRSW)
· Ejection Fraction
· Time-Varying Maximum Elastance E(t)
· End-Systolic Elastance (Ees)
· Max and Min dV/dt
Arterial Elastance (Ea)
CAPILLARY FILTRATION COEFFICIENT
A measure of the capillaries in the lung permeability to water; specifically, the volume of fluid filtered in unit time through a unit area of membrane per unit pressure difference, taking into account both hydraulic and osmotic pressures. This technique is utilized using Grass TechnologiesTM Polyview 16 Data Acquisition and Analysis System.