An investigation of the change in the amount of blood pumped by the failing heart following the institution of a therapeutic procedure may be of interest from two points of view: (a) from the standpoint of the pathogenesis of congestive heart failure and (b) from the standpoint of the mechanism whereby a given procedure produces improvement. The present study was undertaken with the idea of elucidating the first of these problems, but certain information concerning the second question has also been obtained.
The subject—in the basal state—was brought to the laboratory in a wheelchair. The consumption of oxygen was determined in duplicate by analyses of samples of the expired air which was collected in a Tissot spirometer. The arteriovenous oxygen difference was measured by the three sample acetylene technic. Two rebreathings were usually done, the samples being procured at approximately twenty, twenty-four and twenty-eight seconds in the first, and