Incidence and outcomes of protamine reactions in patients undergoing catheter ablation of atrial fibrillation

Background: Aggressive anticoagulation with heparin to maintain an activated clotting time (ACT) >300 s is required during catheter ablation of atrial fibrillation (AF) to reduce the risk of systemic thromboembolism. The purpose of this study is to describe the incidence and outcome of protamine reactions and analyze the risk factors in patients undergoing catheter ablation of AF. Methods: The patient population included 242 consecutive patients (193 men, age 57.6∈±∈10.8 years) with drug refractory AF who underwent catheter ablation and received protamine immediately following catheter ablation to reverse the effects of heparin. Fifty eight of these patients had prior exposure to protamine. Results: Three of the 242 patients in our study developed an adverse reaction to protamine (1.2%). Although each of the three protamine reaction presented in a dramatic fashion with profound hypotension, all three patients responded to medical treatment and did not experience clinical sequelae. Age, gender, type of AF, number of ablations, prior exposure, diabetes mellitus, and ejection fraction did not predict the occurrence of these reactions. Conclusion: This study reports, for the first time, the incidence and outcomes of protamine reaction in patients undergoing catheter ablation of AF. The results of this study reveal that protamine reactions present in a dramatic fashion often with profound hypotension. Although the incidence of protamine reactions in this setting is low (1.2%), they do occur. Electrophysiologists who use protamine need to be aware of this reaction and the appropriate therapeutic interventions.