Introduction: Pulmonary vein isolation (PVI) is an established procedure to treat atrial fibrillation (Afib) but it increases periinterventional thromboembolic burden¹ . Literature provides ambiguous results about ablation effects on different hemostatic markers. The aim of this study was to assess the difference between two used PVI methods (cryoablation and radiofrequency ablation (RFA)) in postinterventional platelet reactivity (PR). Patients and Methods: We analyzed PR in 168 consecutive patients undergoing PVI due to Afib in our institution using Multiplate function analyzer. Blood samples for PR measurements were drawn prior to the procedure and the on the following morning. In total, 123 and 45 patients underwent cryoablation and RFA, respectively. There was no difference in demographics and baseline platelet parameters between the groups (Table 1). ASPItest, ADPtest and TRAPtest were used as assays for the quantitative in vitro determination of PR triggered by arachidonic acid, adenosine diphosphate and thrombin receptor activating peptide-6, respectively. [ABSTRACT FROM AUTHOR]