After LAAI, an unexpectedly high incidence of LAA thrombus formation and stroke was observed despite OAC therapy.

Background: Cryoballoon-based pulmonary vein isolation (PVI) has emerged as an effective treatment for atrial fibrillation. The most frequent complication during cryoballoon-based PVI is phrenic nerve injury (PNI). However, data on PNI are scarce. Methods: The YETI registry is a retrospective, multicenter, and multinational registry evaluating the incidence, characteristics, prognostic factors for PNI recovery and follow-up data of patients with PNI during cryoballoon-based PVI. Experienced electrophysiological centers were invited to participate. All patients with PNI during CB2 or third (CB3) and fourth-generation cryoballoon (CB4)-based PVI were eligible. Results: A total of 17 356 patients underwent cryoballoon-based PVI in 33 centers from 17 countries. A total of 731 (4.2%) patients experienced PNI. The mean time to PNI was 127.7±50.4 seconds, and the mean temperature at the time of PNI was −49±8 °C. At the end of the procedure, PNI recovered in 394/731 patients (53.9%). Recovery of PNI at 12 months of follow-up was found in 97.0% of patients (682/703, with 28 patients lost to follow-up). A total of 16/703 (2.3%) reported symptomatic PNI. Only 0.06% of the overall population showed symptomatic and permanent PNI. Prognostic factors improving PNI recovery are immediate stop at PNI by double-stop technique and utilization of a bonus-freeze protocol. Age, cryoballoon temperature at PNI, and compound motor action potential amplitude loss >30% were identified as factors decreasing PNI recovery. Based on these parameters, a score was calculated. The YETI score has a numerical value that will directly represent the probability of a specific patient of recovering from PNI within 12 months. Conclusions: The incidence of PNI during cryoballoon-based PVI was 4.2%. Overall 97% of PNI recovered within 12 months. Symptomatic and permanent PNI is exceedingly rare in patients after cryoballoon-based PVI. The YETI score estimates the prognosis after iatrogenic cryoballoon-derived PNI. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03645577.

Background:The arctic front cryoballoon (AF-CB) provides effective and durable pulmonary vein isolation (PVI) associated with encouraging clinical outcome. The POLARx cryoballoon incorporates unique features and design changes that may translate into improved efficacy, safety and further simplified balloon-based procedures. Efficacy and safety of the novel POLARx cryoballoon was compared to the fourth generation AF-CB (AF-CB4).Methods and Results: Twenty-five consecutive patients with paroxysmal or persistent atrial fibrillation were prospectively enrolled, underwent POLARx-based PVI (POLARx group) and were compared to 25 consecutive patients treated with the AF-CB4 (AF-CB4 group). All PVs were successfully isolated utilizing the POLARx and AF-CB4. A significant difference regarding the mean minimal cryoballoon temperatures reached using the AF-CB4 and POLARx (−50±6°C vs. −57±7°C, P=0.004) was observed. Real-time PVI was visualized in 81% of POLARx patients and 42% of AF-CB4 patients (P<0.001). Utilizing the POLARx, a trend towards shorter median procedure time (POLARx: 45 [39, 53] min vs. AF-CB4: 55 [50, 60] min; P=0.062) was found. No differences were observed between AF-CB4 and POLARx concerning catheter maneuverability, catheter stability and periprocedural complications. Conclusions:The novel POLARx showed similar safety and efficacy compared to the AF-CB4. A higher rate of real-time PV recordings and significantly lower minimal balloon temperatures were observed using the POLARx.