The impact of overt hypothyroidism on left ventricular mechanical synchrony : speckle tracking echocardiography study / 中华超声影像学杂志

ABSTRACT

Objective To explore the impact of hypothyroidism on left ventricular ( LV ) mechanics using two-dimensional speckle tracking imaging ( 2D-STI ) . Methods Forty-two patients with newly diagnosed overt hypothyroidism ( HT ) were prospectively collected as the case group and 47 subjects matching by age ,gender and hypertension history were enrolled as control group . All participants received comprehensive echocardiography examination ,and 2D-STI was used to assess LV global longitudinal strain ( GLS) and mechanical dispersion ( MD ) . The inter-group difference in GLS and MD ,correlations with thyroid hormones and reproducibility were evaluated . Results LV GLS at both sectional ( apical 4- ,3- ,2-chamber views) and global levels were significantly impaired in the HT group than the control group [ ( - 21 .3 ± 3 .2) ％ vs ( - 23 .9 ± 2 .9) ％ ,( - 20 .4 ± 3 .8 ) ％ vs ( - 22 .7 ± 2 .9 ) ％ ,( - 21 .2 ± 3 .9) ％ vs ( - 23 .9 ± 2 .5) ％ ,( - 20 .9 ± 3 .4) ％ vs ( - 23 .5 ± 2 .3) ％ ;all P < 0 .01] . Similarly ,MD at both sectional ( apical 4- ,3- ,2-chamber views) and global levels were significantly prolonged in the HT group than the control group[ 3 .4 ms vs 0 .9 ms ,2 .2 ms vs 0 .7 ms ,2 .3 ms vs 1 .7 ms and 12 .2 ms vs ( 5 .9 ± 2 .6) ms ;all P < 0 .01] . No significant correlation was found between MD and GLS ,left ventricular ejection fraction ( LVEF) ( r = 0 .12 , P = 0 .27 ; r = - 0 .17 , P = 0 .10) . Weak correlations were found between MD and FT3 ,FT4 ,TSH( r = - 0 .34 , P = 0 .01 ; r = - 0 .38 , P = 0 .005 ; r = 0 .31 , P = 0 .02) . Conclusions Primary overt HT is associated with impaired LV deformation and increased systolic dyssynchrony . LV MD is a promising parameter for assessment of myocardial impairment in HT .