Objective To summarize the clinical characteristics of children with cardiac enlargement and ventricular preexcitation, and to evaluate the safety and effectiveness of radiofrequency ablation (RFCA) in the treatment of this type of disease. Methods A retrospective analysis was conducted on the clinical data of 6 children with cardiac enlargement and ventricular preexcitation in our hospital, and the clinical efficacy and follow-up of ablation treatment were analyzed. Results The median age of 6 children (2 males and 4 females) was 2.0 years at the time of detection of cardiac enlargement, all of whom had overt ventricular preexcitation without tachycardia manifestations and unsatisfactory recovery of cardiac size and cardiac function after regular anti-heart failure medication. All 6 children underwent RFCA, and the median age of the patients at the time of RFCA was 4.4 years. All of the children had intraoperative electrophysiologic examination confirming the presence of right-sided accessory pathway, including 4 cases of right free wall accessory pathway, 2 cases of right septal accessory pathway, and 2 cases of multiple accessory pathways. Postoperative follow-up found that all children had improved ventricular wall motion incoordination and ventricular wall kinematics compared with the previous ones, and postoperative cardiac function was firstly recovered and returned to normal in the shortest postoperative period of 1 month, while cardiac size recovered more slowly and returned to normal in the shortest period of 1.7 years. Conclusions Ventricular preexcitation with cardiac enlargement and no accompanying tachycardia is common in clinical practice. When drug treatment is not effective, RFCA can be attempted to remove the factors of bypass preexcitation. For the diagnosis and differential diagnosis of this type of disease, especially it is a safe and effective treatment. Cardiac enlargement combined with ventricular preexcitation without tachycardia is clinically common, and RFCA can be attempted to remove the factors that cause bypass preexcitation when medication is ineffective, and RFCA not only helps in the diagnosis of this type of disease, but it is also a safe and effective means of treatment.