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  • br Conclusion br Conflict of interest This work was supporte

    2019-05-16


    Conclusion
    Conflict of interest This work was supported by Medtronic Japan. MN received honoraria from Medtronic Japan, St. Jude Medical Japan and Boston Scientific Japan. YE and TI received honoraria from Medtronic Japan. HS received honoraria from Japan Lifeline. YA, TT, and KK are employees of Medtronic Japan.
    Acknowledgments
    Introduction Over the past decade, catheter-based pulmonary vein isolation (PVI) has become a widely accepted therapy for patients with symptomatic drug-refractory atrial fibrillation (AF) [1]. Termination of persistent AF (PerAF), however, often requires extensive ablation including ablation at complex fractionated atrial electrogram (CFAE) sites and high cox 2 inhibitors frequency (DF) sites and/or multiple linear ablations in addition to the PVI [2–5]. CFAE and/or high DF sites have been shown to be effective targets for AF termination, thus suggesting their importance in the maintenance of AF [2–9]. Electrogram-based ablation has been used for an additive ablation strategy based on the hypothesis that critical CFAEs and high DFs are spatiotemporally stable. Nonetheless, it remains unclear whether the location of these electrical activities will be stable or variable at different time points while creating 3-dimensional (3D) maps, as the electrographic signals are sequentially recorded from a roving multipolar catheter. Simultaneous recordings from multiple sites at different time points are the only means by which we can evaluate the spatial and temporal distribution of CFAEs and high DFs. Therefore, we investigated the spatial and temporal distribution of CFAEs and high DFs in the left atrium (LA) during AF with the use of a multi-electrode basket catheter.
    Material and methods
    Results
    Discussion
    Conclusions
    Conflict of interest
    Acknowledgments
    Introduction Atrial fibrillation (AF) is a common condition that is associated with a 5-fold increased risk of stroke [1]. While oral anticoagulants have traditionally been utilized for stroke reduction in AF patients, their use has been suboptimal because of concerns over bleeding [2]. Catheter ablation [3–5] and left atrial appendage (LAA) occlusion [6] may reduce stroke risk without the need for oral anticoagulation. The mechanism of the former is related to sinus rhythm maintenance, whereas the latter acts through exclusion of the LAA, which is the dominant site of thrombus formation in patients with non-valvular AF [7,8]. As the long-term freedom from AF associated with catheter ablation procedures is not ideal [9], an appealing solution for stroke reduction would be the placement of an LAA occlusion device at the time of an AF ablation procedure. Such a combined approach may result in very low rates of stroke, potentially similar to those reported in patients undergoing surgical MAZE procedures with LAA ligation [10,11], as well as minimize the need for a repeat invasive procedure requiring transseptal catheterization. To date, one small series evaluating the feasibility of LAA occlusion at the time of catheter ablation comprising pulmonary vein (PV) isolation has been published [12,13]. In addition, we know of two clinical trials currently under way that are evaluating the merits of this combined strategy (LAALA-AF Registry [14] and LAA Occlusion after catheter ablation of AF (Clinical Trials.gov identifier number: NCT01695824) [15]). However, despite the enthusiasm among electrophysiologists for simultaneous PV isolation and LAA occlusion, it is unknown whether PV isolation triggers morphologic changes of the LAA that may affect the ability to safely perform concomitant LAA occlusion. That is, radiofrequency (RF) ablation in the region of the left PV may alter the size, shape, and tissue characteristics of the LAA ostium. Knowledge of any such changes would be important as it may affect the approach to and safety of percutaneous LAA occlusion at the time of an ablation procedure, thereby influencing future clinical studies in this field. In this pilot study, we address this knowledge gap by reporting on changes in the size and tissue characteristics of the LAA os in patients undergoing PV isolation and additional left atrium (LA) substrate modification as assessed using gadolinium-enhanced cardiovascular magnetic resonance imaging (CMR).