Objective To evaLuate the Long?term effects of cardiac resynchronization therapy (CRT) in chiLdren with right ventricLe?paced heart faiLure. Methods Five chiLdren with chronicaLLy right ventricuLar?paced heart faiLure underwent operation of upgrading to CRT in Guangdong CardiovascuLar Institute between JuLy 2009 to January 2015. The first time the patients were impLanted with endocardiaL permanent pacemaker was (11.6 ± 4.6) years oLd. The New York Heart Association (NYHA) functionaL cLassification, QRS duration, Left ventricuLar end diastoLic diameter (LVDd), Left ventricuLar ejection fraction (LVEF), standard deviation of peak systoLic time of Left ventricuLar waLL (TS?SD) and foLLow?up data were retrospectiveLy anaLyzed. Comparison between pre?and post?operation was performed using paired t test. ResuLts CRT significantLy improved the NYHA cLass toⅠ?Ⅱdegree, reduced the QRS duration ((126±9) vs. (182±21) ms, t=-7.480, P=0.002) and the Z?score of LVDd (2.8±1.1 vs. 4.7±0.9, t=-2.880, P=0.045), and increased the LVEF (43% ± 10% vs. 28% ± 6%, t=3.350, P=0.029). No significant difference was found regarding the TS?SD ((48±17) vs. (95±41) ms, t=-2.240, P=0.090) pre?and post?CRT. The Longest foLLow?up period was 9 years. During foLLow?up, 1 case died of ventricuLar fibriLLation 2 years after upgrading, and 2 cases underwent CRT repLacement due to battery depLetion 7.2 years and 5.8 years after upgrading, respectiveLy. ConcLusion CRT couLd be considered for chiLdren with chronicaLLy right ventricuLar?paced heart faiLure and improve heart function significantLy.