Prolonged vortex formation during the ejection period in the left ventricle with low ejection fraction: a study by vector flow mapping.

Abstract

Vortex formation in the left ventricle (LV) can be visualized by novel vector flow mapping (VFM) based on color Doppler and speckle tracking data. The aim of this study was to evaluate the impact of a vortex during the ejection period using VFM. Color Doppler images were obtained to produce VFM images in 80 subjects (20 normal, 29 with dilated cardiomyopathy, and 31 with old myocardial infarction). The duration of the LV vortex was measured and expressed as the ratio to the ejection time (VTRe). The VTRe showed significant correlations with EDV (ρ=0.672, p<0.001), ESV (ρ=0.772, p<0.001), EF (ρ=-0.783, p<0.001), left atrium diameter (LAd) (ρ=0.302, p=0.007), stroke volume (ρ=-0.600, p<0.001), e' (ρ=-0.389, p<0.001), a' (ρ=-0.314, p=0.005), s' (ρ=-0.512, p<0.001), and E/e' (ρ=0.330, p=0.003). The diastolic parameters (e', a', E/e', LAd) were not correlated when they were adjusted by EF. In the normal LV, a vortex existed for only a limited time during the early ejection period. In contrast, the lower the EF was, the longer the vortex remained during systole. Evaluation of vortices by VFM may noninvasively provide novel insights into the pathophysiology of impaired cardiac function.