The aim of the study is to compare platelet activation, activation of the coagulation and inflammation cascade during catheter ablation for atrial fibrillation using radiofrequency or pulsed-field energy. Patients with atrial fibrillation and standard indication for ablation according to the current guidelines will be randomized to ablation either using radiofrequency of pulsed-field energy. The endpoints will be parameters of platelet activation, activation of coagulation, and changes in inflammatory markers during ablation.

Catheter ablation for atrial fibrillation (AF) , i.e. pulmonary vein isolation, is associated with the activation of platelets, coagulation cascade and inflammatory parameters. Thrombus in the left atrium could arise on sheaths or wires, but the highest risk presents the ablations itself. Radiofrequency ablation leads to immediate endocardial damage that presents strong pro-thrombotic milieu. To avoid thrombus formation on catheters in the left atrium, heparin with target activated clotting time (ACT) of 250-300 is given during the procedure.

Newly, pulsed - field ablation has been widely emerged. Since the pulsed-field energy presents substantially different kind of ablation energy, and the mechanism of action differs substantially (no thermal injury, no acute necrosis), also the effect on platelets, coagulation and inflammatory parameters could differ substantially.

The investigators therefore initiate a study comparing the effect of radiofrequency and pulsed-field ablation on parameters of platelet activation, coagulation and inflammation during catheter ablation.

Patients with AF indicated for catheter ablation according current guidelines will be randomized to radiofrequency or pulsed-field ablation. The procedure will be done using standard approach from one or both femoral veins under moderate analgesia. Using intracardiac echocardiography, and by means of SL1 sheath (Abbott, USA), transseptal puncture will be done. In patients in the radiofrequency arm, Lasso (circular mapping catheter) will be inserted in all four pulmonary veins, and using Smart Touch ablation catheter (Biosense Webster, USA), pulmonary vein isolation will be done with target ablation index of 400 on anterior and superior aspects of pulmonary veins and 350 of the posterior wall of the left atrium. In patients in the pulsed-field arm, SL1 sheath will be replaced by Faradrive sheath (Boston Scientific, USA), and pulmonary vein isolation will be done using Farawave catheter (Boston Scientific, USA).

Blood samples will be drawn at the beginning of the procedure from the right atrium (S1), after the transeptal puncture before the ablation from the left atrium (S2), after the ablation when all 4 pulmonary vein are isolated (S3), 24 hours after the procedure before patient discharge (S4), and 3 months after the procedure during follow-up.

Platelet activity will be determined using flow cytometry (membrane expression of P-selectin (CD62P) antigen, active part of the glycoprotein IIb/IIIa (PAC-1), CD 41/61 antigens). Changes in coagulation will be determined by measuring D-dimers and fibrin-monomers. Regarding the inflammatory parameters, plasma concentration of interleukin-6, and membrane activation antigens on leukocytes will be assessed using flow cytometry.

Inclusion Criteria:

• atrial fibrillation - paroxysmal of persistent

Exclusion Criteria:

• pregnancy
• left atrium > 60 mm
• mechanical valve
• known prothrombotic state
• rheumatic heart disease
• severe valve disease (i.e. mitral insufficiency > 2, aortic stenosis)

Study protocol will be shared on demand

After study initiation