Circulation, Vol 76, 32-43, Copyright © 1987 by American Heart Association
MR Starling, RA Walsh, LJ Dell'Italia, GB Mancini, JC Lasher and JL Lancaster
This investigation was designed to calculate left ventricular maximum
time-varying elastance (Emax), to define the relationship between Emax and
pressure-volume (P-V) relations at other, more easily defined measured of
end-systole, and to determine whether these measures of left ventricular
contractile function can be normalized in man. Accordingly, we studied 10
subjects with simultaneous high-fidelity micromanometer left ventricular
and ascending aortic pressure recordings and biplane contrast
cineangiograms at control conditions and during infusion of methoxamine and
nitroprusside. Emax was defined as the maximum slope of the linear relation
of isochronal, instantaneous P-V data points obtained from each of the
three loading conditions. Left ventricular end-systole was also defined for
each loading condition as: the time of the maximum P-V ratio (maxPV),
minimum ventricular volume (minPV), (-)dP/dtmin [(-)dP/dtPV], and zero
systolic flow approximated by the central aortic dicrotic notch (AodiPV).
The mean heart rates and LV (+)dP/dtmax were insignificantly altered during
the three loading conditions. Isochronal Emax ranged from 3.38 to 6.73 mm
Hg/ml (mean 5.48 +/- 1.23 [SD] mm Hg/ml) and the volume-axis intercepts at
zero pressure ranged from -2 to 51 ml (mean 18 +/- 16 ml). The isochronal
slope calculations were reproducible (r = .97 to .99). The end-systolic P-V
slope values for the maxPV, minPV, (- )dP/dtPV, and AodiPV relations
correlated with isochronal Emax (r = .90, .88, .69, and .74, respectively).
The average slope values for these end-systolic P-V relations, however,
underestimated the mean Emax (p less than .01 to p less than .001). The
mean extrapolated volume- axis intercepts for these end-systolic P-V
relations also underestimated that for Emax. Finally, the isochronal Emax
and other end-systolic P-V relation slope values demonstrated inverse
linear relationships with left ventricular mass (r = -.68 to -.91, p less
than .05 to p less than .001). Only the Emax volume-axis intercepts showed
a linear relationship with left ventricular end-diastolic volume (r = .75).
Thus we conclude that the time-varying elastic properties of the left
ventricle can be calculated in man, that commonly used end- systolic P-V
relations significantly underestimate isochronal Emax, and that
normalization of isochronal Emax and other end-systolic P-V relation slope
values might be performed in man with left ventricular mass; no obvious
relationship between volume-axis intercepts and measures of left
ventricular or body size was apparent.
ARTICLES
The relationship of various measures of end-systole to left ventricular maximum time-varying elastance in man
This article has been cited by other articles:
 |
|
 |
|
  F. Haddad, S. A. Hunt, D. N. Rosenthal, and D. J. Murphy Right Ventricular Function in Cardiovascular Disease, Part I: Anatomy, Physiology, Aging, and Functional Assessment of the Right Ventricle Circulation, March 18, 2008; 117(11): 1436 - 1448. [Full Text] [PDF]
|
|
|
|
 |
|
 Z. B. Popovic, U. N. Khot, G. M. Novaro, F. Casas, N. L. Greenberg, M. J. Garcia, G. S. Francis, and J. D. Thomas Effects of sodium nitroprusside in aortic stenosis associated with severe heart failure: pressure-volume loop analysis using a numerical model Am J Physiol Heart Circ Physiol, January 1, 2005; 288(1): H416 - H423. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Z. Popovic and S Gradinac Partial left ventriculectomy improves left ventricular end systolic elastance in patients with idiopathic dilated cardiomyopathy Heart, March 1, 2000; 83(3): 316 - 319. [Abstract] [Full Text]
|
|
|
|
|
|
M. R. Starling Effects of Valve Surgery on Left Ventricular Contractile Function in Patients With Long-term Mitral Regurgitation Circulation, August 15, 1995; 92(4): 811 - 818. [Abstract] [Full Text]
|
|