STUDIES IN CONGESTIVE HEART FAILURE

Abstract

The O and CO 2 contents of arterial and femoral venous blood have been determined in patients with heart disease, in individuals with edema but no cardiac disease, and in subjects with no edema and no heart disease. The femoral venous O content tends to be high in patients with edema. The O utilization tends to be lower in edematous legs. The changes found at a given time bear no relationship to the progress of the disease, but are proportional to the amount of edema present, regardless of whether it is increasing or decreasing. When patients are in a state of digitalis intoxication or have diminished alkali reserve of the blood, the O utilization tends to be high, regardless of the amount of edema. The amount of CO2 gained by the blood parallels, in general, the amount of O lost by the blood in the various conditions which have been mentioned. As these studies have been concerned with the blood from edematous tissues they may have value in the interpretation of edema as a symptom. These studies have led the authors to believe that edema causes an increased local blood flow. This seems to be brought about in the following manner: Edema (acting in the tissues, as in the lungs, as a barrier to the diffusion of O) [forward arrow] diminished tissue O tension [forward arrow] increased local blood flow and decreased O utilization. The symptoms of congestive heart failure are not essentially due to diminished minute output of the heart. Since utilization is faulty it is possible for the cardiac output to be increased and at the same time inadequate. Edema, itself a symptom of congestive heart failure, throws an additional load on the heart and is thus secondarily a further cause of "heart failure." The patient with "heart failure" suffers, when at rest, from circulatory inefficiency rather than from cardiac insufficiency.