Data Collection
The NHR data encompassed all ablation procedures. From the NHR database we obtained the data for the current analysis, including procedural data, demographic characteristics, medical history, and data related to prior ablation procedures. Starting from 2022, the ablation registry was expanded to include an additional set of variables related to baseline characteristics, procedural details, and follow-up data. This new variable set encompassed the following variables: hypertension, coronary artery disease (CAD), cerebrovascular accident/transient ischemic attack (CVA/TIA), diabetes mellitus, pulmonary vein reconnection status, ablation strategy used during repeat ablation, date of the last known follow-up, use of anti-arrhythmic drugs at the time of the last follow-up, date of recurrence after re-ablation, and type of atrial arrhythmia recurrence. This expanded dataset was collected by eight hospitals. Data regarding patients’ follow-up were obtained, including recurrences after a 90-day blanking period, the use of antiarrhythmic drugs during last known cardiac follow-up, and additional repeat ablation procedures performed the first repeat procedure analyzed here. Follow-up was calculated starting from the date of the first repeat ablation. Follow-up occurred according to each center’s standard protocol. Patients were usually scheduled for outpatient clinic visits at 3-, 6-, and 12-months, and every 12 months thereafter. During these visits, assessments were conducted for AF-related symptoms, adverse events, and ECG or 24-hour Holter monitoring to detect any recurrence of atrial arrhythmias, as determined by the physician’s discretion. Patients were otherwise seen for emergency visits in case of symptomatic recurrence, during which 12-lead ECG would be performed. The last known follow-up was considered the end of the follow-up period for the survival analysis, which was impacted by the occurrence of recurrence and/or repeat ablation.