• for repeat ablation; adverse outcome/intolerance of antiarrhythmic agent requiring cessation or change of drug
• Composite endpoint of: Atrial arrhythmias persisting >24 hrs or requiring antiarrhythmic drug therapy; need for cardioversion/hospital admission during the study period

• Each individual endpoint from the composite above [ Time Frame: 6 weeks ]
• Total number of days with episodes of an atrial arrhythmia [ Time Frame: 6 weeks ]

• Each individual endpoint from the composite above
• Total number of occurrences of symptomatic atrial arrhythmia during the study period
• Total number of days with episodes of an atrial arrhythmia

The purpose of this study is to examine the overall effectiveness of anti-arrhythmic medicines (to control heart rhythm) prescribed after an ablation procedure for atrial fibrillation.

Atrial fibrillation (AF) is the most common heart rhythm disorder in the US and it is associated with shortness of breath, palpitations, stroke occurrence and increased mortality. Traditional treatment for AF includes anticoagulation, drugs that slow the heart rate and antiarrhythmic agents. More recently, catheter based treatments to address atrial fibrillation have been developed, which involves using radiofrequency energy to isolate the arrhythmogenic foci localized in the pulmonary veins.

During the first weeks following pulmonary vein isolation (PVI), it is not unusual for patients to experience early recurrences of atrial fibrillation or atrial tachycardia due to irritability from the ablation. While these arrhythmias tend to resolve over time, it is nevertheless standard practice to prescribe antiarrhythmic drugs for the first 2-3 months after the intervention to prevent these early recurrences. However, the efficacy of this practice has never been formally evaluated. In addition, we have identified a small group of patients whose atrial tachycardias have terminated after cessation of antiarrhythmic therapy, suggesting that proarrhythmia from these agents may promote reentrant tachycardias in some patients. We therefore designed a study protocol that will evaluate the usefulness of short term antiarrhythmic drug therapy in order to prevent atrial fibrillation and atrial tachycardia episodes during the first 6 weeks following PVI.

The target population of the study includes all patients with paroxysmal atrial fibrillation referred for PVI. After the ablation procedure, patients will be randomized to receive or not receive antiarrhythmic drugs for a period of 6 weeks. Arrhythmia occurrence during this period will be monitored via twice daily transtelephonic monitoring. Clinical visits including a physical exam and 12 lead ECG recording will be scheduled at 6 weeks. The primary endpoint of the study will be a composite endpoint including 1) atrial arrhythmias persisting > 24 hours or requiring initiation of antiarrhythmic therapy 2) need for cardioversion/hospital admission 3) need for repeat ablation or 4) adverse outcome/intolerance of antiarrhythmic agent requiring drug cessation or change during the 6 week follow up period.

• Drug: propafenone; flecainide; sotalol; dofetilide
• Device: Radiofrequency catheter ablation

• Other: Subjects receive membrane-active anti-arrhythmic medication after ablation. See intervention list below.
• Other: Subjects do not receive membrane-active anti-arrhythmic medications after ablation.

Inclusion Criteria:

• Adult patients meeting ACC/AHA criteria for paroxysmal atrial fibrillation (episodes typically last no more than 7 days and are self-terminating)
• Eligible for pulmonary vein isolation
• Able to tolerate antiarrhythmic medication

Exclusion Criteria:

• Age <18
• Persistent or permanent atrial fibrillation (episodes last >7 days and require cardioversion)
• Antiarrhythmic treatment for indication other than atrial fibrillation
• Contraindication or intolerance to all antiarrhythmic medications
• Primary physician unwilling to withhold antiarrhythmic drugs for duration of the study
• Failure to obtain informed consent