Effect of diastolic dysfunction on intraventricular velocity behavior in early diastole by flow mapping

Abstract

Intraventricular velocity distribution reflects left ventricular (LV) diastolic function and can be measured non-invasively by flow mapping technologies. We designed our study to compare intraventricular velocities and gradients, obtained by vector flow mapping (VFM) technology during early diastole in consecutive patients diagnosed with mild and advanced diastolic dysfunction at echocardiography and a control group with a purpose to validate the hypothesis of relationship between new parameters and severity of diastolic dysfunction and conventional markers of elevated LV filling pressure. Two-dimensional streamline fields were obtained using VFM technology in 121 subjects (57 with normal diastolic function, 38 with mild diastolic dysfunction and 26 with advanced diastolic dysfunction). We measured several velocities and calculated a gradient along the selected streamline, which we compared between groups and correlated them with conventional echocardiographic parameters. Apical intraventricular velocity gradient (Gr_IV) was the lowest in control group, followed by mild and advanced diastolic dysfunction groups (5.3 ± 1.9 vs. 6.8 ± 2.5 vs. 13.6 ± 5.0/s, p < 0.001) and showed good correlation with E/e' (r = 0.751, p < 000.1). Gr_IV/e' ratio was the strongest single predictor of severity of diastolic dysfunction. Different degrees of diastolic dysfunction affect the Intraventricular velocity behavior during early diastole obtained by VFM. Gr_IV could discriminate between groups with different levels of diastolic dysfunction and was closely associated with classical echocardiographic indices of elevated LV filling pressure. Gr_IV/e' ratio has a potential to become a single parameter needed to assess left ventricular diastolic function.

Keywords: Blood flow dynamics; Diastolic dysfunction; Echocardiography; Intraventricular velocity gradient; Vector flow mapping.