Data collection and follow-up
Baseline characteristics were recorded when patients were enrolled in CARF. The demographic characteristics included age, gender, and body mass index. The clinical characteristics included type of AF, AF duration, alanine transaminase, creatinine, hemoglobin, QRS duration, echocardiography information, concomitant diseases, and medications.
Oral anticoagulants (warfarin or non-vitamin K antagonists) were prescribed for at least 2 months after ablation. International normalized ratio (INR) should be maintained between 2.0 to 3.0 in patients taking warfarin. The patients with high risk of stroke were encouraged to continue taking anticoagulation drugs. When to stop anticoagulation therapy was according to the patients’ embolism and bleeding risk and the patients’ intention. Antiarrhythmic drugs were taken after ablation for 3 months if there were no contraindications.
The patients were followed up at 3, 6, and 12 months after enrollment and every 6 months thereafter by professionally trained staff affiliated with CARF. Follow-up was conducted by telephone or outpatient clinic interview to learn about the patients’ clinical events and current situation. 24h-Holter was performed monthly in the first 3 months, which was followed by an ECG and/ or 24h-Holter every 6 months. If patients had clinical symptoms of heart rhythm disorders, the arrhythmias should be confirmed by ECG or Holter.