An angiocardiographic method for directly determining left ventricular stroke volume in man.

• In previous studies from this and other laboratories, rapid biplane angiocardiography has been utilized to quantify left ventricular chamber volume and volume changes in man and experimental animals." Arvidsson measured left ventricular stroke volume in several subjects with valvular heart disease in the course of extensive studies on left atrial volume changes, and Chapman and coworkers' determined left ventricular volume curves and stroke volume in canines and a normal man using a biplane cineangiocardiographic technique. Others have utilized a single-plane technique to determine left ventricular volume in experimental animals." The validity of corrections for x-ray distortion and of calculations of volume from biplane x-rays has been demonstrated using models' 5 and contrast-filled postmortem hearts. Recently, Arvidsson compared left ventricular minute volumes determined by an angiocardiographic method with minute volumes determined by the Fick method and found close agreement in the majority of subjects. In his studies, angiocardiography was performed under conditions of general anesthesia and positive intrathoraeic pressure. In the present study, stroke volumes determined from biplane angiocardiograms were compared with stroke volumes determined by Fick and indieator-