Antiarrhythmic Drugs Assessment in Preventing Atrial Fibrillation

Inclusion Criteria: * at least 18 years old * sick sinus syndrome with pacemaker Class I or Class IIa indication * has a pacemaker which can provide the daily AF burden monitor record for at least 28 days * has at AF record in the past 6 months, the valid AF record includes any of 1. at least one 30 seconds AF holter record 2. at least one 15 seconds 12-ECG record 3. at least 5 minutes long AF episodes record from pacemakers * able and willing to give informed consent Exclusion Criteria: * will have cardiac surgery in the next 6 month or in the waiting list of heart transplantation * NYHA Class III or IV * LVEF \<50% * Reversible AF, such as AF caused by hyperthyroidism or severe postoperative atrial fibrillation * Persistence AF * Expected life expectancy less than 1 year * Planned to be pregnant or be in the feeding period in the next year * Non-stable, decompensated heart failure * Allergy to Amiodarone, Propafenone or Sotalol * Cancer * Clear liver damage ( ALT and/or AST \> 2\*normal limit) * Patients with cardiogenic shock history * Be in the treatment of Amiodarone for more than 3 months or less than 3 months with Amiodarone wash out period less than 30 days * Coronary artery disease (CHD), cardiomyopathy, severe valvular heart disease, severe obstructive pulmonary disease (COPD), long QT syndrome