Background and aims: Immediate recurrence (Im-Recurr), a type of atrial fibrillation (AF) recurrence occurring during the blanking period after radiofrequency catheter ablation (RFCA), has received little attention. Therefore, this study was aimed at exploring the clinical significance of Im-Recurr in patients with AF after RFCA. Methods: This study retrospectively included patients with AF who underwent RFCA at our center. Regression, propensity score matching (PSM), and survival curve analyses were conducted to investigate the effects of Im-Recurr on costs, hospitalization durations, AF recurrence rates, and predictors of Im-Recurr. Results: A total of 898 patients were included, among whom 128 developed Im-Recurr after RFCA. Multiple linear regression analysis revealed that Im-Recurr correlated with greater cost, hospitalization duration, and hospitalization duration after ablation. Logistic regression and PSM analyses indicated that intraoperative electric cardioversion (IEC) was an independent predictor of Im-Recurr. The follow-up results suggested a significantly higher 1-year cumulative AF recurrence rate in the Im-Recurr group than the control group. Conclusions: Im-Recurr significantly increases the cost and length of hospitalization for patients with AF undergoing RFCA and is associated with an elevated 1-year cumulative AF recurrence rate. IEC serves as an independent predictor of Im-Recurr. Registration number: ChiCTR2200065235.