Sample size and power
SCEs
The targeted sample size is 230 (115 in each group). The sample size was calculated based on the primary hypothesis. The rate of MRI‐detected SCEs after CA of AF has been reported to be comparable between CB and RF ablation, ranging from 10% to 30% in the observational studies.When the primary endpoint is observed in half of the total sample size (116 patients), early stopping of the study for futility will be considered based on the conditional power at an interim analysis, which will be reviewed by the Data and Safety Monitoring Board (DSMB). A simulation suggested a very limited power loss with a potential early stopping for futility, and the targeted power is expected to be achieved with this sample size.