Comparison of ejection fraction and zonal mean velocity of myocardial fiber shortening.

To determine the extent of cardiac involvement until a diminished ejection fraction (EF) is present, zonal mean velocity of circumferential fiber shortening (Vcf) was measured from the left ventriculogram in 36 patients. The longitudinal axis (apex to mid-point of the aortic valve plane) in right anterior oblique view was divided into four equal parts by three perpeendicular chords. Zonal Vct and percent shortening along the proximal, middle and distal chords were measured. The results of this study indicate that a normal EF is frequently associated with a reduced Vct in one or even two zones. A reduced EF is generally accompanied by a diminished Vct in all three zones of the heart. In addition, a close correlation was found between zonal Vct and percent shortening. Hence the latter, which is much simpler to measure, can be instead of Vct Ejection fraction as a measure of myocardial performance is not as sensitive as Vct, especially in hearts with asynchrony of contraction.