Abstract: AIM:To investigate the characteristics and treatment strategy of accessory atrioventricular pathway (AP) transient recurrence in patients with preexcitation syndrome (WPW) after radiofrequency catheter ablation (RFCA). METHODS: We included 1378 WPW patients who underwent successful RFCA. Those patients with intermittent WPW or unsuccessful RFCA were excluded. Clinical data, electrophysiological study results, clinical results and follow-up information were analyzed. RESULTS: According to RFCA results, 1 378 patients were divided into three groups. There were 1356 patients with successful RFCA and were classified according to the direct successful group. Eight patients with transient recurrence of AP conduction after RFCA were divided into transient recurrence group, and 14 patients with persistent recurrence of AP conduction were classified as recurrence group. Durations of local ventricular electrogram of ablation site preceded the onset of QRS without statistical difference between transient recurrence group and direct successful group ［(27±9) ms vs.(28±6) ms］, but these time intervals were significantly shorter in recurrence group than direct successful group ［(23±9) ms vs.(28±6) ms, P<0.05］. The time from delivering radiofrequency energy to disappearance of surface ECG preexcitation wave was longer in the recurrence group than in the other two groups ［(12±6) s vs.(5±3) s (6±3) sec, P<0.05］. The successful RFCA sites of AP were located at the right posterior septum (n=2), right free wall (n=3), left posterior septum (n=1) and left free wall (n=2) in transient recurrence group. WPW relapsed and re-disappeared within 24 h after RFCA in transient recurrence group. The recurrence time and recurrence lasting time were both shorter in transient recurrence group than in recurrence group ［(9±5) h vs.(56±38) day, P<0.05 and (12±6) h vs. 72 h, P<0.05］. Five of the eight patients with transient recurrence accepted a second EP study 72 h after RFCA, and EP study confirmed that the AP were eliminated successfully. After >6 months follow-up, the eight patients had no WPW and tachycardia recurrence. CONCLUSION: Those cases with transient recurrence of AP antegrade conduction after RFCA of WPW syndrome should be observed for several days. If the pre-excitation wave spontaneously disappears, it is unnecessary to again perform EP study.