M.I. P/N 004-2163 Rev. C
3
loops that are an excellent illustration of the cardiac cycle in normal or diseased conditions
of the living heart.
With the MPVS
Ultra
, P-V loops may be captured during pharmacological, therapeutic
and hemodynamic interventions, allowing comprehensive, beat-by-beat evaluation of the
fundamental mechanical properties of the heart.
The MPVS
Ultra
supports the use of Millar’s ultra-miniature P-V catheters for small
animal studies and multi-segment P-V catheters for large animal studies. Both the small
and large animal catheters couple a high-fidelity pressure sensor with volume electrodes
spaced to match the longitudinal diameter of the left ventricle. The electrodes allow
volume data to be acquired across a single segment of the left ventricle.
The MPVS
Ultra
has an internal 20 kHz fixed-frequency oscillator, which generates either
a 20µA or 100µA RMS sine-wave current that creates an electric field within the left
ventricle of the heart. The system measures a corresponding voltage that is proportional to
the electric field. The system continuously measures this voltage across the receiving
electrodes. The measured voltage changes during the cardiac cycle as the left ventricular
blood volume rises (diastolic filling phase) and falls (systolic ejection phase).
The measured voltage decreases as volume increases (resistance of blood pool decreases,
conductance of blood pool increases) and the measured voltage increases as volume
decreases (resistance of blood increases, conductance of blood pool decreases). The system
then converts measured voltages into ventricular conductance, which is proportional to the
changes in ventricular volume as stated above.
The MPVS
Ultra
also measures high fidelity pressure signals using a Millar catheter. The
solid-state pressure sensor uses the same technology found in Millar’s extensive line of
Mikro-Tip
®
catheter pressure transducers. The use of the pressure sensor located between
the conductance/volume electrodes allows the simultaneous measurement of pressure and
conductance/volume, enabling a researcher to obtain high quality P-V loops from the
rapidly beating hearts of small animals. The MPVS
Ultra
system should ONLY be used
with a Millar catheter.
