Role of Coumadin in Preventing Periprocedural Thrombo-Embolism as a Complication of Radio Frequency Catheter Ablation in High-risk Atrial Fibrillation Patients

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice, affecting 2.3 million people in the United States (1). A major cause of stroke, AF substantially increases the risk of thromboembolism which necessitates oral anticoagulation therapy (OAT) for high-risk patients. Radiofrequency percutaneous catheter ablation (RFCA) is an effective strategy for the treatment of symptomatic drug-refractory atrial fibrillation. However, periprocedural cerebrovascular accident (CVA) due to thrombus or air embolism remains one of the most serious complications of AF ablation. In spite of precautions taken before, during, and after the ablation to minimize the risk of CVA, the reported event rate remains 0.5-2.8% (2).

The incidence of thromboembolic events is dependent on the extensiveness of the ablation procedure as well as the periprocedural anticoagulation strategy (2). Some studies have described charring and soft thrombus formation when the temperature exceeds 100 degree C during RFCA, which probably is caused by blood protein denaturation and coagulation (3). Currently an open saline irrigation-tip ablation catheter (3.5 mm Thermocool catheter) is used which reduces the thermal injury by keeping the temperature under control (4), while enabling the operator to use high wattage RF energy to effectively ablate the arrhythmogenic focus.

The two most utilized periprocedural OAT strategies are; 1) discontinuation of Coumadin three to five days prior to ablation, utilization of heparin or enoxaparin before the procedures, and "bridging" low molecular weight heparin with Coumadin after ablation, and 2) RFCA with continuation of Coumadin before, during and after the procedure (2) without any change in dosage. Limited data are available regarding the risk of thromboembolism with and without periprocedural Coumadin in AF patients undergoing catheter ablation .The aim of this prospective randomized study is to evaluate the effect of the above two OAT strategies on the incidence of TE within 48 hours post-RFCA.

Patient Selection, Treatment and Follow-up Period:

Patients randomized as study group would continue Coumadin without any periprocedural change while undergoing catheter ablation. Those randomized as control group would discontinue Coumadin 3-4 days prior to ablation and replace it with heparin till the end of the procedure and bridge LMWH with Coumadin 48-72 hours after ablation.