Short-term and medium-term changes of the left ventricular ejection fraction in children with dilated cardiomyopathy complicated with complete left bundle branch block and the predictive value of relevant electrocardiogram indexes / 中华实用儿科临床杂志

ABSTRACT

Objective:To investigate the short-term and medium-term changes of the left ventricular ejection fraction (LVEF) and the predictive value of relevant electrocardiogram (ECG) indexes in children with dilated cardiomyopathy (DCM) complicated with complete left bundle branch block (CLBBB).Methods:Children clinically diagnosed with DCM in the Department of Heart Center, Women and Children′s Hospital, Qingdao University and Beijing Anzhen Hospital, Capital Medical University between November 2011 and August 2020 were retrospectively recruited.According to the combination of CLBBB, they were divided into CLBBB group and non-CLBBB group.Echocardiogram and ECG were regularly performed.Short-term and medium-term changes of LVEF based on the 1-5-year follow-up data were compared between groups.COX proportional hazards model and Kaplan-Meier multiplicative limit method were used to analyze the predictive value of ECG indexes of LVEF changes in children with DCM combined with CLBBB.Results:Ninety-four children with DCM were enrolled, including 35 cases in CLBBB group and 59 cases in non-CLBBB group.There was no difference in baseline LVEF between groups.However, significant differences were found in QRS duration, corre-cted QT interval(QTc), R peak time in lead V 5 (T V5R) and QRS notching or slurring between groups ( P<0.05). LVEF of all children showed an upward trend within one year after onset, while the Z value of eft ventricular end diastolic diameter(LVEDd) showed a downward trend, and the two indexes tended to be stable within 1 - 5 years.The Z value of LVEDd in CLBBB group was significantly higher than that of non-CLBBB group, while LVEF was significantly lower (all P<0.05). The mean LVEF of CLBBB group slightly fluctuated around 50%, that of LVEF in non-CLBBB group was 60%.The multivariate COX regression analysis showed that QRS duration ( HR=0.979; 95% CI 0.960-0.999, P<0.05) and QTc ( HR=0.988; 95% CI 0.979-0.998, P<0.05) were independent predictors of LVEF recovery in children with DCM.Kaplan-Meier method showed a significant difference of LVEF normalization between DCM children with different QRS durations ( P<0.05), which was also detected in those with QTc interval ( P<0.05). Conclusions:LVEF of children with DCM combined with CLBBB increases in the short term after standard treatment, and then being stable.CLBBB can affect the recovery of left ventricular systolic function in children with DCM.Moreover, QRS duration and QTc interval are independent predictors of LVEF recovery in DCM children.