Late systolic indices of ventricular function: noninvasive derivation in congestive heart failure.

The slopes of end-systolic pressure/end-systolic dimension and volume relations have been found to be relatively load-independent indices of left ventricular contractility. Noninvasive determination of these relationships has been performed in normal subjects and has been found to reflect baseline and drug-induced changes in ventricular contractility. Three late systolic indices of ventricular contractility were noninvasively determined in subjects with chronic congestive heart failure to determine the feasibility of the method and to assess the linearity and slopes of the relationships in this population. All relations were linear with individual correlation coefficients ranging from 0.86 to 0.99. The mean +/- SD slope was 42.8 +/- 26.4 mm Hg/cm for the end-systolic pressure-dimension relation, 0.59 +/- .42 mm Hg/ml for the end-systolic pressure-volume relation, and 48.7 +/- 32.2 mm Hg/cm for the peak systolic pressure-end-systolic dimension relation. All slopes were markedly reduced compared to those reported in normal individuals. The relative degree of depression was greater for the pressure-volume slope than for the pressure-dimension slope, which is explained by the relationship between volume and dimension in dilated ventricles. These data indicate that measurement of late systolic indices of ventricular contractility by this noninvasive technique is feasible in subjects with congestive heart failure and yields reduced slopes consistent with the diminished contractile state of this population. Pressure-volume rather than pressure-dimension relations may more accurately reflect inotropic state in dilated ventricles.