Abstract: Objectives　To investigate different treatments and prognosis on complete left bundle branch block (CLBBB) in children after closure of perimembranous ventricular septal defect (VSD). Method　Eighteen cases with CLBBB after perimembranous VSD intervention diagnosed from February 2009 to June 2019 were enrolled in this study. The patients were divided into 4 groups according to different treatments such as close follow-up, glucocorticoid treatment, removing closure device and CRT treatment. The follow-up results including clinical signs and symptoms, chest radiography, electrocardiogram (ECG), echocardiography (ECHO) and type B natriuretic peptide (BNP) were analyzed. Results　A total of 8 patients accept close follow-up for 5 to 10 years without any symptoms or signs, showed normal cardiac function (NYHA I) and normal left ventricular ejection fraction (LVEF) by ECHO. The left ventricular end-diastolic diameter (LVDD) were larger according to references. There were 4 cases suffered CLBBB on 1 to 4 days after intervention. They recovered after accepting glucocorticoid treatment for 1 week. The ECG, ECHO and BNP tests were normal after 6 month. There were 2 cases admitted to remove the closure device and accepted surgical repair. The first case accepted surgery after 6 months of intervention. The ECG after postoperative 1 week showed complete right bundle branch block until now. The other observation target including ECHO and BNP were normal after one-year follow-up. Another case accepted surgery 7 years after intervention, but complete atrioventricular block occurred after surgery and not recovered 1 week later. The patient accepted double chamber pacemaker implantation and showed normal cardiac function excepting the enlarged LVDD after 1 year follow up. There were 4 cases with heart failure accepted standard medicine therapy for at least six months and had no obvious improvement. Three (3) of them accepted CRT implantation, another case accepted permanent pacemaker implantation (left atrial sensing, left ventricular pacing) for personal reasons. The QRS wave was shorter than 150 millisecond after surgery. One (1) patient accepted CRT implantation died after 3 days because of acute heart failure. The cardiac function was significantly improved and LVEF were increased at least 45% in other 3 patients after one- or two-years medicinal therapy, and The LVDD and BNP were decreased significantly compared with the data before implantation. Conclusions　CLBBB would be occur after VSD intervention which will lead to desynchronization of ventricular contractions and heart failure. For the patients suffered CLBBB early after intervention, the glucocorticoid treatment may be useful. Another choice is to remove the device, but it would lead to complete atrioventricular block. CRT implantation is an alternative treatment for patients with heart failure.

Key words: closure of ventricular septal defect;　complete left bundle branch block;　heart failure;　cardiac resynchronization therapy