M.I. P/N 004-2163 Rev. C
20
Volume
Display Conductance/Volume Units
Use this button to change the display to conductance or volume units as desired. This
button does not affect the output voltage.
Measured Volume
This display indicates the current composite volume as measured by the MPVS
Ultra
. The
value displayed is based upon an analog summation of all active segments. This analog
sum is the COMPOSITE output on the front panel.
The blue or orange scale is a graphical representation of the composite volume signal.
When the user opts to view units of volume (
μ
l or ml), the calculation of this value takes
into account segment length, rho and alpha chosen on the Catheter Configuration tab.
The output shown in the MPVS
Ultra
Control interface does not account for the volume
attributed to parallel conductance of the myocardium. If desired, this correction can be
made in the PVAN
Ultra
software or the user’s acquisition software.
Transducer and Electronic Calibration Buttons
The active button is green. To measure a volume signal from the catheter, click the
Transducer
button.
In order to calibrate the data acquisition system from voltage to volume or conductance
units, the system has six internal sets of resistors that are used as inputs of known
conductance. Only two to three buttons are available at any given gain range. (Available
buttons are beige; others are gray.) The available selections are designed to span the
expected segmental conductance inputs for typical animals ranging from mice to domestic
livestock. The gain setting on the Catheter Configuration tab controls the available input
range in order to maximize the use of the available voltage output range. The indicated
values on the buttons are the conductance or volume to be output by each segment, not the
composite total.
The values indicated on the calibration buttons change according to the present
configuration. When volume units are displayed, Baan’s equation is used, so the present
values of alpha, rho, and segment length are used, as noted in Measured Volume above.
Since the values on the buttons represent the per-segment conductance or volume, be sure
to multiply by the number of active segments when entering the calibration value for the
Composite Volume channel. The Composite Volume or Composite Conductance value is
displayed by the software when one of the calibration buttons is pressed.
ECG Calibration
The ECG Calibration interface allows the user to generate a calibration signal for the ECG
output, control the source of the signal, and enable or disable the notch filter.
Current Value
The numerical readout displays the current ECG signal measured by the MPVS
Ultra.
ECG Scale
The ECG Scale graphically displays the current ECG signal measured by the MPVS
Ultra
.
Detailed Operation
