目的：观察左室射血分数降低的心力衰竭（heart failure with reduced ejection fraction,HFrEF）患者的心脏机械收缩同步性情况,进而探讨采用超声心动图右室面积变化分数（right ventricular fractional area change,RVFAC）在该人群中筛查心脏机械收缩不同步者的临床价值。方法：54例HFrEF住院患者接受心电图、常规超声心动图、组织多普勒及二维斑点追踪显像检查,并根据超声心动图RVFAC结果（<18%、18%~34%和≥34%）分组,观察并比较各组间的心脏电学不同步及机械不同步（包括心室间不同步、房室不同步、左心室内不同步）情况。结果：根据RVFAC结果将患者分为3组,第1组RVFAC<18%（右心室功能显著下降）19例（35.2%）;第2组RVFAC为18%~34%（轻度下降）19例（35.2%）;第3组RVFAC≥34%（正常）16例（29.6%）。3组患者间的完全性左束支传导阻滞发生率无差异,但第1组QRS时限较第3组明显延长[（146.7±37.5） ms比（105.7±31.0） ms,P=0.003];与第2组及第3组比较,第1组的电学不同步发生率较高（以下顺序均为第1组比第2组比第3组,72%比58%比28%,P=0.012）,房室不同步[LV-FT/RR,（37.1±10.2） ms比（45.6±8.4） ms比（48.5±5.6） ms,P<0.01]以及心室间不同步[心室间机械延迟时间（interventricular mechanical delay, IVMD）,（49.9±29.9） ms比（26.4±27.0） ms比（6.9±35.4） ms,P<0.01]程度更重。左心室内不同步方面,3组间发生率和不同步指数差异无统计学意义。与右室功能正常的第3组患者比较,第1组的室间隔闪烁（septal flash, SF）现象检出率增高（47%比37%,P=0.02）,而第1组与第2组间无差异。结论：在HFrEF患者中,存在严重右室收缩功能异常者,其心脏机械收缩不同步的发生率更高,程度更重。超声心动图RVFAC可用于筛查HFrEF患者中需要接受心脏再同步化治疗者。

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.