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Introduction: The circular catheter compatible with current cryoballoon system for atrial fibrillation (AF) ablation is exclusively sensed by impedance‐based electro‐anatomical mapping (EAM) system, limiting the accuracy of maps. We aim to investigate the feasibility and safety of a magnetic‐based circular mapping catheter for AF ablation with cryoballoon. Methods: Nineteen consecutive patients who underwent pulmonary vein isolation (PVI) with cryoballoon for paroxysmal or persistent AF were included. EAMs of left atrium (LA) created by the LASSOSTAR™NAV catheter (Lassostar map) before and after PVI were compared to that generated by a high‐density mapping catheter (Pentaray map) from different aspects including structural similarity, PV angle, LA posterior wall (LAPW) and low voltage areas (LVAs), and the amplitude of far field electrograms (FFEs) recorded by catheters. Results: All patients had successful PVI without major complications. With similar mapping time and density, the LA volume calculated from the Pentaray map and Lassostar map were comparable. There were no significant differences in PV angle of all PVs and PW area (16.8 ± 3.2 vs. 17.1 ± 2.8, p =.516) between Pentaray map and Lassostar map. High structural similarity score was observed between two maps (0.783 in RAO/LAO view and 0.791 in PA view). Lassostar map detected lesser but not statistically significant extension of LVA (13.9% vs. 18.3%, p =.07). Amplitude of FFE was larger at the right superior PV on Lassostar map (0.21 ± 0.16 vs. 0.14 ± 0.11 mV, p =.041) compared to that on the Pentaray map. Conclusion: In our initial experience, PVI with cryoballoon and magnetic‐based circular LASSOSTAR™NAV catheter was safe and effective based on the accurate LA geometry it created. [ABSTRACT FROM AUTHOR]

The production of pyrogenic (fumed) silica is increasing worldwide at a 7% annual growth rate, including expanded use in food, pharmaceuticals, and other industrial products. Synthetic amorphous silica, including fumed silica, has been generally recognized as safe for use in food products by the Food and Drug Administration. However, emerging evidence from experimental studies now suggests that fumed silica could be hazardous due to its siloxane ring structure, high silanol density, and "string-of-pearl-like" aggregate structure, which could combine to cause membrane disruption, generation of reactive oxygen species, pro-inflammatory effects, and liver fibrosis. Based on this structure-activity analysis (SAA), we investigated whether calcination and rehydration of fumed silica changes its hazard potential in the lung due to an effect on silanol density display. This analysis demonstrated that the accompanying change in surface reactivity could indeed impact cytokine production in macrophages and acute inflammation in the lung, in a manner that is dependent on siloxane ring reconstruction. Confirmation of this SAA in vivo, prompted us to consider safer design of fumed silica properties by titanium and aluminum doping (0-7%), using flame spray pyrolysis. Detailed characterization revealed that increased Ti and Al doping could reduce surface silanol density and expression of three-membered siloxane rings, leading to dose-dependent reduction in hydroxyl radical generation, membrane perturbation, potassium efflux, NLRP3 inflammasome activation, and cytotoxicity in THP-1 cells. The reduction of NLRP3 inflammasome activation was also confirmed in bone-marrow-derived macrophages. Ti doping, and to a lesser extent Al doping, also ameliorated acute pulmonary inflammation, demonstrating the possibility of a safer design approach for fumed silica, should that be required for specific use circumstances.