Relationship between the Abnormal Diastolic Vortex Structure and Impaired Left Ventricle Filling in Patients with Hyperthyroidism

Abstract

Intraventricular hydrodynamics plays an important role in evaluating cardiac function. Relationship between diastolic vortex structures and left ventricular (LV) filling is still rarely reported. This study aimed to evaluate the evolution of intraventricular fluid dynamics during diastole in hyperthyroidism (HT), and to explore the alteration of hydromechanics characteristics with sensitive indices. Forty-three patients diagnosed with HT were divided into two groups according to whether myocardial damage existed: simple hyperthyroid group (HT1, n = 21) and thyrotoxic cardiomyopathy (HT2, n = 22). Twenty-seven age- and gender-matched healthy volunteers were enrolled as the control group. Offline vector flow mapping (VFM model) was used to analysis the LV diastolic blood flow patterns and fluid dynamics. Hemodynamic parameters like area (A), circulation (C) and intraventricular pressure gradient (△P) in different diastolic phase (early, mid, and late) were calculated and analyzed. HT2, with a lower E/A ratio and left ventricular ejection fraction (LVEF), had larger left ventricular end-diastolic diameter (LVEDD) and left atrium diameter (LAD) compared with the control group and HT1(P <0.05). Vortex displayed a typical biphasic temporal course during diastole in these three groups. In early diastole, vortices of the controls were smaller and weaker than those of HT1, larger and stronger than those of HT2 (P < 0.05 for both). Vortices of these three groups increased in mid-diastole at the same pace and differences remained (P < 0.05 for both). Then vortices in HT2 developed so fast that exceeded the control group, but still below HT1 during the end of diastole. The intraventricular pressure gradient during early and mid-diastole (△PE, △PM) were higher in HT1 and lower in HT2 compared with those of the control group (P <0.05). However, the intraventricular pressure gradient (△PL) of HT2 increased and was higher than that of the control group in late diastole (P < 0.05). Good correlation could be found between CE and E/A (P < 0.05), CM and △PM (P < 0.01), CL and FT3 (P < 0.05). VFM can reflect the abnormal left ventricular filling by showing the changes of left ventricular diastolic vortex.