Relationship Between Changes in Left Ventricular Dimensions and the Ejection Fraction in Man

Left ventricular length and calculated diameter were derived from angiocardiograms in 24 subjects with various heart diseases. Chamber diameter was noted to decrease an average of 27.5% from end-diastole to end-systole, and chamber length decreased 13%. Only subjects with calculations of left ventricular mass differing less than 25% from end-diastole to end-systole were accepted in order to avoid effects of spurious increases in end-systolic wall thickness on calculated diameter. Patients with localized disorders of contraction were also excluded. An extremely close linear relationship between the percentage change in diameter and the ejection fraction was demonstrated. Analysis of the radii of curvature showed that the lateral wall usually straightens during systole. However, if extreme ventricular dilatation is present, the lateral-wall curvature increases with systole. The possible implications of this alteration in contraction pattern and its effect upon the ejection fraction were discussed.