161 Catheter ablation of atrial fibrillation on uninterrupted warfarin using standard and duty cycled radiofrequency energy: safe and effective

Introduction Catheter ablation (CA) for atrial fibrillation (AF) is growing exponentially. Although ablation for paroxysmal AF (PAF) is associated with shorter procedure times and less extensive left atrial ablation vs persistent AF thromboembolic complications can occur in both sub-groups. Inadequate anticoagulation leads to thrombotic complications and excessive anticoagulation can lead to bleeding risks. Many centres adopt a policy of discontinuing warfarin in the immediate run-up to the procedure, covering the procedure with unfractionated heparin and “bridging” postoperative patients with low molecular weight heparins (LMWH) back onto warfarin. We wished to determine the safety of CA for AF with a therapeutic INR using both the single transseptal approach and duty cycled radiofrequency energy (RF) with non irrigated PVAC catheters and the double transseptal puncture technique using irrigated RF catheters and either CARTO or NAVX electroanatomical mapping.

Methods A retrospective analysis of 173 patients who underwent CA for AF while taking uninterrupted warfarin. Procedural target International Normalised Ratio (INR) was 2–3 with a peri-procedural target ACT of 300–350 s. In sub therapeutic INR patients weight adjusted LMWH was used post procedure with warfarin until INR was >2. Standard technique employed was large area circumferential ablation using conventional RF energy or pulmonary vein isolation using duty cycled RF energy. Data was gathered for demographics, procedural INR, total dose of unfractionated heparin, fluoroscopy time, and type of radiofrequency energy used. Endpoints were minor bleeding, major bleeding (requiring transfusion), vascular complications, pericardial tamponade and stroke/TIA within 28 days of the procedure.

Results There were 128/173 male patients, age range between 21 and 73 years (mean 57 years). 122 underwent ablation for PAF and 51 for persistent AF. Mean procedural INR was 2.4 (range 1.7–3.9). Mean unfractionated heparin dose was 6000 units (range 1000–14 500). Mean fluoroscopy time for the PVAC group was 23.4 mins (range 8.3–50.1 mins). Mean fluoroscopy time for CARTO/NAVX group was 31mins (range 14.10–58.44 mins). There were no major bleeding complications. There was 1 minor bleeding complication with a groin pseudoaneurysm. There were 2 cases of pericardial tamponade (2/173%–1.2%) both managed with percutaneous pericardial drainage. There were no stroke/TIAs.

Conclusion These data demonstrate that CA for AF by both single and double transseptal technique using both standard RF and duty cycled RF while maintaining a therapeutic INR is a safe procedure. Maintaining a therapeutic INR reduces the risk of embolic events associated with “bridging” heparin without an increase in bleeding complications. This technique is convenient for patients and avoids switching between LMWH and warfarin and ensures patient safety by maintaining therapeutic anticoagulation before, during and after the procedure.