SYNCHRONICITY OF VENTRICULAR CONTRACTION: OBSERVATIONS COMPARING HAeMODYNAMIC EFFECTS OF ATRIAL AND VENTRICULAR PACING

Abstract

In the course of earlier investigations it was noted that when the heart was paced by ventricular stimulation, mean left atrial pressure was higher for any given cardiac output, aortic pressure, and stroke work than when the atrium was paced at the same rate. Although the changes observed in those initial observations were not always striking, it was felt desirable to clarify the mechanisms by which they took place and to find what influenced their magnitude. Accordingly, a more systematic investigation was undertaken.