Left ventricular systolic intraventricular flow field assessment in hyperthyroidism patients using vector flow mapping

Abstract

Intraventricular hydrodynamics is considered an important component of cardiac function assessment. Vector flow mapping (VFM) is a novel flow visualization method to describe cardiac pathophysiological condition. This study examined use of new VFM and flow field for assessment of left ventricular (LV) systolic hemodynamics in patients with simple hyperthyroidism (HT). Thirty-seven simple HT patients were enrolled as HT group, and 38 gender- and age-matched healthy volunteers as control group. VFM model was used to analyze LV flow field at LV apical long-axis view. The following flow parameters were measured, including peak systolic velocity (Vs), peak systolic flow (Fs), total systolic negative flow (SQ) in LV basal, middle and apical level, velocity gradient from the apex to the aortic valve (ΔV), and velocity according to half distance (V1/2). The velocity vector in the LV cavity, stream line and vortex distribution in the two groups were observed. The results showed that there were no significant differences in the conventional parameters such as left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVEDD) and left atrium diameter (LAD) between HT group and control group (P>0.05). Compared with the control group, a brighter flow and more vortexes were detected in HT group. Non-uniform distribution occurred in the LV flow field, and the stream lines were discontinuous in HT group. The values of Vs and Fs in three levels, SQ in middle and basal levels, ΔV and V1/2 were higher in HT group than in control group (P<0.01). ΔV was positively correlated with serum free thyroxin (FT4) (r=0.48, P<0.01). Stepwise multiple regression analysis showed that LVEDD, FT4, and body surface area (BSA) were the influence factors of ΔV. The unstable left ventricular systolic hydrodynamics increased in a compensatory manner in simple HT patients. The present study indicated that VFM may be used for early detection of abnormal ventricle contraction in clinical settings.

Thyroid gland dysfunction and its effect on the cardiovascular system: a comprehensive review of the literature

“…A study with vector flow mapping (VFM), a novel method to visualise and describe a cardiac pathological condition, showed no significant difference in left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVEDD), and left atrium diameter (LAD) between hyperthyroid patients and the control group (p > 0.05). Bozkus et al also showed that LV systolic haemodynamic increases in a compensatory manner and suggested that VFM could be used to detect early pathological ventricular contraction in clinical REVIEW settings [79]. A study by Bozkus et al on the effect of short-term L-thyroxine (LT4) suppression therapy on the cardiac function is shown in Table 3.…”

Numerical analysis of the internal biased flow mechanism of the siphon outlet pipe under the action of axial flow pump

“…Additionally, by increasing the axial velocity component, the unwanted flow patterns near the impeller’s inlet are suppressed and the internal flow field of the pipe is improved. The entire pipe of an axial flow pump device of the siphon outlet pipe was numerically simulated by Zhou et al 7 using SST k-ω and Zwart cavitation models. When the flow passed through the guide vane and under the influence of centrifugal force, the vacuum collapsed, allowing the flow to attain a significant average vortex angle, thus avoiding large deliquescence and backflow in the outlet conduit and making the head rise.…”

Relationship between the abnormal diastolic vortex structure and impaired left ventricle filling in patients with hyperthyroidism

“…It is considered to be one of the representative methods for visualization of blood flow in vivo that can compete with CMR and CE-PIV. [8,9] …”