Analysis of left and right ventricular size and shape, as determined from human casts. Description of the method and its validation.

A method is described to produce life-like left and right ventricular casts of 22 human hearts and to store their surface coordinates on magnetic tape for the analysis of ventricular shape and of angiocardiographic volume determination methods. According to their shape, experienced cardiologists divided these casts into diastolic, systolic and intermediate subgroups. On the basis of X-ray silhouettes and computer-simulated projections, single-plane as well as biplane model volumes were calculated with the multiple-slices and the area--length methods for various ventricular orientations. The mean correction factors (CF), relating actual and model volumes vary considerably with respect to cardiac phase and orientation. The systolic CFs are smaller than the diastolic ones, their averaged ratio being 0.74 for the left and 0.86 for the right ventricular casts. In general, the reported CFs are smaller than those published by other authors, which is attributed to different cast-production procedures. The described method uses selective, equql, and simultaneous filling of both ventricles, which prevents an unphysiologic shift of the interventricular septum.