Circulation, Vol 56, 540-544, Copyright © 1977 by American Heart Association
WH Gaasch, OH Bing, JS Cole and HG Hanley
The effects of a single premature contraction (PC) on left ventricular
diastolic distensibility was studied in man, in the conscious chronically
instrumented dog, and in the isolated (isovolumic) blood perfused dog
heart. In the isolated dog heart at a constant volume, there was no
difference in end-diastolic pressure when control diastolic pressure was
compared to that following a PC. In man and conscious dogs, there was no
difference between the overall pressure- volume or pressure-length plots
when control diastolic data were compared to data from the diastole
immediately following a PC (no change in the modulus of chamber stiffness).
In the intact circulation of man dog, increased filling during the post PC
pause causes the ventricle to operate higher on the steep (stiffer) portion
of its pressure-volume or pressure-length curve (decrease in
preload-dependent compliance). Thus, although a PC does not alter the
modulus of chamber stiffness, a preload-dependent change in compliance may
occur during post PC diastole.
ARTICLES
Postextrasystolic compliance of the left ventricle
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