Outcome measurement after the first session
After the initial session, patients were followed-up at an outpatient clinic in our institution and a nearby practitioner every month at minimum thereafter. At each follow-up, electrocardiography and 24-h Holter testing were performed, if necessary. Recurrence was defined as an atrial arrhythmia lasting ≥30 s in examination tests after a blanking period of 3 months after ablation regardless of the use of anti-arrhythmic drugs. Repeat ablation was considered when patients had a recurrence of AF with intolerable symptoms, frequent occurrence, or refractoriness to anti-arrhythmic drugs. However, some patients underwent repeat sessions within the blanking period due to the recurrence of AF, which was left at the discretion of the attending physician.
Oral anticoagulants were continued for at least three months after the first session. During the follow-up, we discontinued oral anticoagulant administration when the patients were free from AF recurrence and had a low risk of comorbidities, as defined by a low CHADS2score and absence of history of stroke. Any related outcomes after discharge, including heart failure or AF hospitalization, pacemaker implantation, cardiovascular intervention, and cardioversion were assessed after the first session in all patients undergoing repeat sessions as found in the patient medical records.