Comparison of CLOSE Guided and High Density Mapping Guided Catheter Ablation of Paroxysmal Atrial Fibrillation

CLOSE protocol is among the latest methods of catheter ablation of AF. According to this protocol, ablations are guided by ablation index, which takes into account ablation time, the contact force and power supplied by the ablation catheter. In this protocol the distance between individual ablation lesions is less than 6 millimeters (mm), thus ensuring the continuity of the ablation line around the pulmonary veins. After ablation, the electrical isolation of pulmonary veins (entry and exit block) is checked with a multi-electrode circumferential catheter. The electrical inactivity of the ablation line itself is thus checked indirectly via the conduction block. According to recent studies, the success rate of catheter ablation with this protocol after one procedure at one year is approximately 90%. Investigators believe that the presence of electrical activity within the ablation line, which does not translate into and out of the pulmonary veins during the procedure and is not detected by the currently used mapping technique, significantly affects the subsequent clinical success of the procedure. Investigators assume that high-resolution mapping of the ablation line would identify areas of electrical activity within the ablation line (dormant conduction) and that the ablation of these areas during the first procedure would significantly affect both the long-term isolation of the pulmonary veins and the clinical success of the procedure.

The aim of this study is to compare long-term clinical efficacy and efficacy of pulmonary vein isolation of two different methods of catheter ablation for treatment of AF. Participants will be randomised into two groups. In the first group isolation of pulmonary veins will be performed following a modified CLOSE protocol, the isolation will be checked with multipolar circumferential catheter. In the second group the ablation will be performed with the same method but the isolation of pulmonary veins will be checked with high-resolution mapping looking for dormant conduction in the pulmonary vein antra.

Hypothesis:

investigators expect that the incidence of the recurrence od AF in the high resolution mapping group will be lower during clinical follow-up. Investigators also expect that durable pulmonary vein isolation will be present in higher proportion of participants where high resolution mapping was performed.

Study protocol: