The Effects of Mitral Regurgitation on the Pattern of Instantaneous Aortic Blood Flow Clinical and Experimental Observations

Abstract

Instantaneous ascending aortic blood flow was recorded at operation in five patients with severe, pure mitral regurgitation, and in nine dogs in which mitral regurgitation was produced experimentally under controlled conditions. In both the patients and the experimental animals, the pattern of aortic flow was abnormal during mitral regurgitation: peak flow occurred early, the percentage of total forward flow was abnormally high during the first half of the ejection period and abnormally low during the last quarter. When stroke volume, heart rate, and aortic pressure were maintained constant, mitral regurgitation also resulted in increases in peak flow, mean ejection rate, and maximum acceleration of flow. These abnormalities of the aortic flow patterns are attributable to inability of the ventricle to sustain forward ejection during late systole in the presence of severe regurgitant flow through the mitral valve.