Withdrawn: It was decided not to proceed with the study at this time.

Both warfarin and dabigatran have been used for stroke prophylaxis at the time of catheter ablation of atrial fibrillation. Although the risks of thromboembolism and bleeding with warfarin are well established, the relative risk and benefit of dabigatran in this setting are unknown. The purposes of the study are to assess the efficacy of warfarin versus dabigatran in the prevention of stroke and other systemic embolic complications before and after catheter ablation for AF, and to compare the prevalence of serious bleeding complications with the two OAC agents.

• Data from patients collected from 4 US and 1 Canadian medical center
• Retrospective record review of all patients that had undergone catheter ablation of atrial fibrillation during the time period beginning with the initiation of dabigatran therapy for stroke prophylaxis at each center and ending in November 2011.
• Dabigatran study group comprised of all patients that received dabigatran for stroke prophylaxis during the study time period.
• Warfarin comparison group to be selected from all patients that received warfarin for stroke prophylaxis during the identical study time period.
• Warfarin patients will be numbered sequentially
• A subgroup of warfarin patients identical in number to the dabigatran patients at each center will be selected using random number generator.

Patient data sets will be de-identified and compiled

• Master data set to be stored in Excel file
• Statistics to be performed with SAS (Cary, NC)
• Continuous data to be expressed as means ± S.D., compared with unpaired t-tests
• Categorical data will be compared with Fisher's exact test or Chi-square
• Complications including any thromboembolic events or any bleeding events will be recorded and the prevalence compared.

Inclusion Criteria:

• All patients undergoing catheter ablation for atrial fibrillation

Exclusion Criteria:

• none (retrospective trial)

All patients undergoing catheter ablation for atrial fibrillation