Post-procedure follow-up
During the first three months after surgical ablation (blanking period), administration of anti-arrhythmic drugs was allowed based on the discretion of the treating physician. The drugs were discontinued at the three-month follow-up if no documented recurrence of ATAs was observed. Patients were followed up in the outpatient clinics every month for the first three months, and every three months thereafter. Twelve- lead ECG and physical examination were performed on each visit. All patients underwent ambulatory 24-hour Holter monitoring one, three, six, and 12 months after discharge. If patients complained of symptoms suggestive of AF, they received additional 24-hour Holter monitoring. ERAT was defined as any recurrence of ATAs within the first three months after surgical ablation. Late recurrence (LR) was defined as an ATA that lasted for at least 30 seconds (s) and occurred up to 12 months after the blanking period. The timing of the last ERAT within the first three months blanking period was recorded as a continuous variable and categorized according to whether it occurred in the first, second, or third month.