AJP - Heart and Circulatory Physiology, Vol 251, Issue 2 236-H241, Copyright © 1986 by American Physiological Society
Technique with lock-in amplifier for real-time measurement of tricuspid valve annulus area
K. Tamiya, M. Higashidate and S. Kikkawa
A new measuring system that permits real-time registration of the tricuspid
valve annular area (TVA) using lock-in amplifier is devised and applied in
open-chest anesthetized dogs. The tricuspid valve annulus was stitched with
a fine, pliable, metal thread made of 10 30-micron urethane resin-coated
copper wires during inflow occlusion. Both ends of the thread were guided
out from the right atrium through a single pinhole in the right atrial
wall. The signal intensity induced in the sense loop is linearly related to
the area encircled by the thread, i.e., the area of the tricuspid annulus.
During control state, TVA varied by an average of 24.5% (3.8-46.5%) of its
maximum. Presystolic peak and valley of TVA due to atrial contraction and a
decrease in TVA during ventricular ejection were generally observed. An
increase in TVA during the initial portion of isovolumic contraction phase
was prominent in dogs with filariasis, whereas in the other dogs it was
not.
