The correlation between QRS duration and mechanical dyssynchrony in patients with congestive heart failure and complete left bundle branch block

Objective To investigate the correlation between the QRS duration and mechanical dyssynchrony in patients with congestive heart failure and complete left bundle branch block(CLBBB).Methods Fifty-one chronic heart failure patients with CLBBB were studied.The patients were divided into two groups,group Ⅰ with QRS duration ≤160 ms and group Ⅱ with QRS duration longer than 160 ms.All the patients underwent conventional echocardiography and tissue Doppler imaging.Results In patients with heart failure and CLBBB,the left ventricular pre-ejection time(LVPT)correlated significantly with QRS duration(r=0.56,P0.01).The LVPT was significantly longer in group Ⅱ than in group Ⅰ.However,the tissue Doppler-derived parameters Ts-SD,Ts-12 and Ts-sep-lat did not show significant difference between the two groups.Conclusions In patients with congestive heart failure and CLBBB,the QRS duration correlated significantly with left ventricular pre-ejection delay,but not intra-ventricular dyssynchrony.