AJP - Heart and Circulatory Physiology, Vol 247, Issue 2 295-H302, Copyright © 1984 by American Physiological Society
Heat transport in the canine left ventricular wall
G. H. ten Velden, N. Westerhof and G. Elzinga
The rate of rise of local myocardial temperature (dT/dt) evoked by left
coronary artery main stem occlusion has been proposed in the literature as
a measure of local metabolic heat production, assuming heat loss due to
diffusion to be negligible. In a previous study (ten Velden, G. H. M., G.
Elzinga, and N. Westerhof. Circ. Res. 50: 63-73, 1982), we showed that this
assumption was not valid. With this information in mind, in an attempt to
study local metabolism, we compared, in anesthetized dogs, the dT/dt with
the temperature distribution over the left ventricular wall. We found the
value of dT/dt to be reproducible in time and to reproducibly depend on
location. Negative values as well as positive values were measured; values
even higher than the maximal possible temperature slope, calculated from
the energy equivalent of left ventricular oxygen consumption and the
specific heat of cardiac tissue, were found. Transmural distribution of the
dT/dt showed positive values epicardially and negative values
endocardially, while, as previously shown, a parabola-like shape of the
transmyocardial temperature distribution existed. Our findings demonstrate
that dT/dt by left coronary main stem occlusion cannot be used as a measure
of local myocardial heat production.
