Correlation of intraventricular pressures at catheterization with postmortem ventricular curvature-thickness indexes in human hearts with aortic valve dysfunction.

It has been proposed that the pressure-producing activity of the ventricular wall segments, left and right free walls, and interventricular septum can be characterized by a curvature-thickness index (CTI) derived from the Laplace relation. Thirty patients with isolated aortic valve disease were examined clinically by cardiac catheterization and at autopsy after coronary arteriography and fixation of the heart in distention. The CTI for each segment was determined from wall thickness on postmortem radiographs, which is considered to represent tension in the Laplace relation, and from curvatures. The left ventricular shape was determined as the ratio of maximal diameter to chamber length. Segment CTIs were compared with peak systolic pressure in the respective chamber or with right and left ventricular pressure differences for the septum. A significant correlation was found between peak pressure and the CTI for ventricular free walls (r = 0.933, P less than 0.001), which was not improved by including ventricular distention as a predictor in a multivariate linear regression analysis. The left ventricular diameter-to-length ratio varied from 0.63 to 0.83 (average 0.74) and showed no significant differences related to type of aortic valve dysfunction. The results suggest that the CTI could serve as a useful index for evaluation of interventricular pressure and might be applicable to noninvasive diagnostic methods as well as postmortem studies.