Funding Acknowledgements Type of funding sources: None. Background The arctic front cryoballon (AF-CB) provides effective and durable pulmonary vein isolation (PVI) associated with encouraging clinical outcome data. The POLARx cryoballoon incorporates unique features which may translate into improved efficacy and safety. Purpose To assess efficacy and safety of the novel POLARx cryoballoon in comparison to the fourth generation arctic front cryoballon (AF-CB4). Methods Twenty-five consecutive patients with paroxysmal or persistent atrial fibrillation (AF) were prospectively enrolled, underwent POLARx based PVI (POLARx group) and were compared to 25 consecutive patients treated with the fourth generation AF-CB (AF-CB4 group). Results A total of 100 (POLARx) and 97 (AF-CB4) pulmonary veins (PV) were identified and all PVs were successfully isolated utilizing the POLARx and AF-CB4, respectively. 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). Despite a certain learning curve utilizing the POLARx a trend towards shorter median procedure time (POLARx: 45 (39, 53) minutes vs. AF-CB4: 55 (50, 60) minutes (p = 0.062) was found. No differences were observed for periprocedural complications. Conclusions The novel POLARx showed similar safety and efficacy compared to the AF-CB4. A higher rate of real-time electrical PV recordings and significantly lower balloon temperatures were observed using the POLARx as compared to AF-CB4.

Funding Acknowledgements Type of funding sources: None. Background Although pulmonary vein isolation (PVI) is an effective treatment strategy for patients with paroxysmal atrial fibrillation (AF), it is associated with limited success rates in patients with persistent AF (PersAF). In this context the left atrial appendage (LAA) was recently identified as a target of catheter ablation especially in PVI non-responders. Although effective, this strategy may cause electromechanical dissociation and was therefore assumed to be associated with an increased risk of thromboembolism despite oral anticoagulation (OAC). Since RF based LAAI showed increased rates of thromboembolism and stable LAAI is difficult to achieve in some cases, Cryoballoon-based LAAI might offer a valuable option to achieve safe and durable LAAI. Recently the fourth generation cryoballoon was introduced. Additionally, the 40% shorter tip potentially increases the safety profile as well as efficacy of CB-based LAAI. Objective To assess safety and efficacy on CB2 vs CB4 based LAAI. Methods Cryoballoon based PVI and LAAI was performed in 20 patients with PersAF and long-standing PersAF. The first 10 consecutive patients were treated by the second-generation cryoballoon (CB2) the last 10 patients were treated by the CB4. LAAI was performed by utilizing a bonus freeze protocol (freezing time 300 seconds + another 300 seconds after LAAI). Results Stable LAAI was achieved after a mean of 2.6+/- 1.7 cryoballoon applications with a mean minimal temperature of -52+/-6 °C. Unless one phrenic nerve palsy (5.6%) of the left phrenic nerve no further periprocedural complications occurred. Successful LAAI was performed in 19/20 (95%). TEE after 6 weeks detected LAA thrombus in 3/10 (30%) patients (CB2 group) and 3/10 patients (30%) (CB4 group), p = 0.99. Successful LAA-closure was performed in 16/20 patients (80%) after a mean of 75+/-59 days. The LAA was durable isolated in 8/9 patients (89%, CB2) and 6/8 patients (75%, CB4), p = 0.56). AF recurrence after 6 weeks was 1/10 (10%, CB2) and 3/9 (33%, CB4), p = 0.26. Conclusions Here we used – to our knowledge – for the first time a CB4 for LAAI, followed by a combined check for LAAI and LAA-closure after 6 weeks, compared to the CB2. LAAI was successfully isolated by both cryo-balloons in the majority of patients. Hence the use of newest cryo-balloon generation for LAAI seems a safe and successful procedure compared to earlier balloon generations. However, a relatively high rate of LAA-Thrombus was detected after LAAI. Therefore, LAA closure is mandatory in this population.

Background Rotors have been postulated to be a major driver of atrial fibrillation (AF). Initial studies demonstrated, that focal impulse and rotor modulation (FIRM) might be an effective therapy for the treatment of paroxysmal AF (PAF). However, data about FIRM-guided ablation strategies without PVI is sparse. Objective To compare the safety and efficacy of FIRM-guided catheter ablation (without PVI; FIRM arm) and second generation cryoballoon (CB2, CB2 arm) based PVI in patients with paroxysmal atrial fibrillation (PAF) and de-novo catheter ablation of AF. Methods In this retrospective single-center study patients with PAF undergoing de-novo ablation of PAF between February 2016 and January 2017 were enrolled. Patients treated with FIRM-guided AF ablation as a standalone therapy without PVI were included and compared with patients undergoing CB2 based PVI. All patients in the FIRM arm were part of the randomized multicenter FIRMAP AF trial (results of this trial will be presented at this meeting). In patients undergoing FIRM-guided ablation, 3D electroanatomical mapping of both atria was performed. Rotor mapping using FIRM technology was conducted in spontaneous or induced AF. The procedural endpoint was the elimination of all rotors and focal impulses; no PVI was performed in those patients. In the CB2 arm, CB based PVI with the procedural endpoint of isolation of all veins was performed. Procedural data and arrhythmia-free survival after 12 months were compared. Results FIRM-guided and CB2 based AF ablation was performed in 22 and 86 patients, respectively. Follow up was completed in 20 and 79 patients LA diameter differed between groups. Otherwise, baseline characteristics did not differ between the FIRM group (mean age 60±11 years, 59.1% males) and the CB2 group (mean age 62±13, 62.4% male). Arrhythmia-free survival including a 90-day blanking period was 25.0% (15/20) in the FIRM group and 86.1% (11/79) in the CB2 PVI group (p=0.000; Figure 1). Procedure duration was significantly longer in the FIRM group (152 [120; 176] minutes) compared to the CB2 PVI group (122 [110; 145] minutes) (p=0.031), whereas radiation dose was lower in the FIRM group (1266 [1027; 2281] cGy·cm2 vs. 3020 [1677; 4215] cGy·cm2). Adverse events (groin complications) occurred in 1 patient (1.2%) in the CB2 PVI group and 5 patients (22.7%) in the FIRM group. Figure 1. Kaplan-Meier-survival curve dem Conclusion De novo ablation of PAF using a FIRM-guided AF ablation only (without PVI) is associated with poor arrhythmia-free survival after 12 months compared to CB2 PVI. These results underline the importance of PVI as the first-line approach in catheter ablation of AF.

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