Hemolysis During Pulsed-field and Radiofrequency Ablation

Catheter ablation presents the most effective treatment for atrial fibrillation (AF). It consists of the electrical isolation of the pulmonary veins. Several kinds of ablation energies can be used for the ablation. So far, the most often kind of energy was radiofrequency (RF) energy that leads to thermal destruction of the cardiac tissue. Newly, pulsed-field (PF) energy was developed for catheter ablation of AF. The use of PF energy consists in ultra-short, high-power application of electrical impulses that lead to fast, non-thermal cardiac tissue destruction.

Despite significant advantages, such as tissue selectivity, short procedure duration, and high durability of ablated lesions, the use of PF energy could also have other adverse effects. Recently, renal failure due to accelerated peri-procedural hemolysis in patients with pre-existed renal disease was described after PF ablation for AF.

The aim of the project is to assess and compare the level of hemolysis during catheter ablation for AF using PF and RF energy. Sixty consecutive patients indicated for catheter ablation for AF according to the standard recommendation (symptomatic paroxysmal or non-paroxysmal AF) will be enrolled. Consecutive patients as they are scheduler for procedure will be enrolled without randomization. In 40 patients (20 paroxysmal and 20 non-paroxysmal), the ablation will be done using PF energy, and in 20 patients using RF energy.

In all patients, intracardiac echocardiography (Accunav, Siemens, Germany) and fluoroscopy will be used for navigation. The procedures will be done as it is currently routinely done in the EP lab. In RF patients, 4 vascular access will be used (one for 10-pole catheter placed into the coronary sinus, one for intracardiac echocardiography probe, and 2 for transseptal sheaths). Two transseptal punctures will be done under the guidance of intracardiac echocardiography using SL1 sheaths (Abbott, USA). One transseptal access will be used for diagnostic circular mapping catheter (Lasso, Biosense-Webster, USA), the other for the ablation catheter. The RF ablation will be performed using SmartTouch or QDot ablation catheters (both Biosense-Webster, USA); however, ablation will be driven by the ablation index even if QDot catheter is used. The RF ablation will be performed using ablation index (400-450 on anterior-superior aspects and 350-400 on posterior aspects of PVs), the QDot Plus (high-power short-duration) regimen won´t be used. The goal will be to achieve the entrance and exit block of all 4 PVs. In non-paroxysmal patients, additional ablations could be done at the discretion of the treating physician (fractionated singnals, lines).

In the PF patients, two vascular access will be obtained. The first will be used for intracardiac echocardiography, the second for the transseptal sheath. Transseptal puncture will be done also using SL1 sheath (Abbott, USA), and using over-the-wire technique, this sheath will be exchanged by the 16-F Faradrive sheath (BSCI, USA). The ablation then will be done using pentaspline ablation catheter (Farawave, Boston Scientific). Four application of pulsed-field energy in basket configuration, and 4 application in flower configuration will be applied to each pulmonary vein. Additional pulsed-field energy application could be added if the signal in PV are present. In non-paroxysmal patients, additional pulsed-field energy application could be applied on the discretion of the operator on the posterior wall, or mitral isthmus.

Blood samples will be taken at the beginning of the procedure from the femoral vein (T1), at the end of the procedure after ablation lesions completion (T2), and one day after the procedure (T3). Hemolysis will be assessed in all three samples 1) using flow cytometry (by means of measurement of "erythrocyte microparticles detected by the presence of antigens glycophorin A and Annexin V) and 2) using ELISA method (assessment of "cell free hemoglobin " concentration). Additionelly, standard biochemistry and blood count analysis will be done from the T1 and T3 samples (the concentration of lactate dehydrogenase, haptoglobin, indirect bilirubin, reticulocytes, and immature reticulocyte fraction).

Primary hypothesis is that the level of hemolysis will be higher after PF ablation compared to RF ablation. Since no studies were published on the hemolysis either during RF or PF ablation, no reliable power calculation can be done.