AJP - Heart and Circulatory Physiology, Vol 250, Issue 4 685-H692, Copyright © 1986 by American Physiological Society
Assessment of slope of end-systolic pressure-volume line of in situ dog heart
Y. Igarashi and H. Suga
The purpose of this study was to establish a new method of assessment of
the slope (Emax) of the end-systolic pressure-volume line (ESPVL) of the in
situ heart. In anesthetized open-chest dogs, an isovolumic contraction was
produced by an aortic occlusion after steady-state ejecting contractions in
the left ventricle. We plotted ventricular pressure measured with a
catheter-tip manometer against time integral of aortic flow measured with
an electromagnetic flowmeter of the last ejecting and the first isovolumic
contraction, assuming the same end-diastolic volume. ESPVL was drawn from
the peak isovolumic pressure-volume point tangential to the left upper
corner of the +/- 3.0 (SE) mmHg/ml (n = 9 dogs) in control run and was
increased by 59 +/- 19% under isoproterenol and decreased by 47 +/- 9%
after propranolol. Emax was little changed by atrial pacing. We conclude
that Emax by this aortic occlusion method is useful for assessment of left
ventricular contractility of the in situ dog heart.
