Study on use of right ventricular fractional area change assessed by echocardiogram for evaluating cardiac synchrony in heart failure patients with reduced left ventricular ejection fraction

Abstract

Objective: To investigate the status of synchronization of cardiac mechanical contraction by means of echocardiogram in heart failure patients with reduced ejection fraction (HFrEF), and analyze use of right ventricular fractional area change (RVFAC) for screening cardiac mechanical dyssynchrony in the population. Methods: A total of 54 hospitalized patients with HFrEF were enrolled, with a mean left ventricular ejection fraction(LVEF) of 33.2%±10.1%. The patients received echocardiogram, echocardiographic and tissue Doppler imaging and 2D speckle tracking imaging. and were divided into three groups according to RVFAC level: Group 1, 19 patients with RVFAC<18%; Group 2, 19 patients with RVFAC 18%-34%; Group 3,16 patients with RVFAC≥34%. The occurrence and degree of of cardiac electrical and mechanical dyssynchrony (atrioventricular dyssynchrony, interventricular dyssynchrony and intraventricular dyssynchorny) were compared between the 3 groups. Results: There was no significant difference in the proportion of complete left bundle branch block among the 3 groups. However, compared with that in Group 3, mean QRS duration was significantly prolonged in group 1[(146.7±37.5) ms vs. (105.7±31.0) ms, P=0.003]. Compared with group 2 and 3, group 1 had higher the prevalence rate of electrical dyssynchrony (QRS>120 ms)（72%, 58%, 28%, P=0.012）, and higher the abnormal rate and more severe degree of both atrioventricular dyssynchrony index[LV-FT/RR, (37.1±10.2) ms vs. (45.6±8.4) ms vs. (48.5±5.6) ms, P<0.01] and interventricular dyssynchrony index [interventricular mechanical delay, IVMD, (49.9±29.9) ms vs. (26.4±27.0) ms vs. (6.9±35.4) ms, P<0.01]. For intraventricular dyssynchorny, asynchrony index showed no significant difference between 3 groups. Furthermore, compared with group 3 which had normal right ventricular function, Group 1 had a higher detection rate of septal flash (SF) sign (47% vs 37% in group 3, P=0.02). Conclusions: In those with HFrEF, patients with severe abnormal right ventricular systolic function have higher risk of cardiac mechanical dyssynchrony, and dyssynchrony is often more severe. RVFAC by echocardiogram may help to select those who will be benefit from cardiac resynchronization therapy in heart failure patients with HFrEF.

Keywords

• |heart failure|cardiac mechanical dyssynchrony|right ventricular systolic function|echocardiography