Pharmacogenetic Study of Antiarrhythmic Drugs for Atrial Fibrillation

Inclusion Criteria:

* ≥ 18 years of age
* History of typical or early-onset symptomatic (≥2 episodes/month) paroxysmal/persistent AF
* ECG that was recorded within 1 month of randomization showing AF
* Eligible for both Flecainide(Class I) and Sotalol (Class III) AAD
* Able to give informed consent

Exclusion Criteria:

* Permanent AF or isolated atrial flutter
* Cardiac or thoracic surgery within the previous 6 months
* Previous use of amiodarone other than short-term use (e.g. for an acute arrhythmia in hospital)
* Medical condition that is likely to be fatal in less than one year
* A history of prior AF ablation
* Have already been tried on 2 or more AADs in the past for AF
* Creatinine clearance \<40 ml/min
* Left ventricular ejection fraction \< 50%
* Contra-indication to a Class I AAD e.g., structural heart disease, or history of MI
* Contra-indication to a Class III AAD, e.g., congenital or acquired long QT syndrome with QTc\>480 ms in females and \>460 ms in males at baseline
* A reversible cause of AF (e.g., hyperthyroidism)
* Females who are pregnant or nursing
* History of severe AV node dysfunction unless an electronic pacemaker is present
* First- or second-degree relative has already participated in the study
* Unable to adhere to study procedures that are strictly for research purposes