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BACKGROUND Radiofrequency high-power ablation appears to be a novel concept for atrial fibrillation (AF). The ablation index (AI) value has been associated with durability of pulmonary vein isolation (PVI). OBJECTIVES This study aimed to report the procedural data and initial results of a combined ablation technique using AI-guided high-power (AI-HP; 50 W) ablation for PVI. METHODS Symptomatic AF patients were consecutively enrolled and underwent wide-area contiguous circumferential PVI. Contact-force catheters were used, ablation power was set to 50 W targeting AI values (550 anterior and 400 posterior). Esophageal temperature was monitored during procedure, all patients underwent postablation esophageal endoscopy. RESULTS PVI was achieved in all (n = 50, mean age: 68 ± 9 years, female: 60%) patients, rate of first-round PVI was 92%. A total of N = 2105 AI-guided ablation lesions were analyzed. Comparing left anterior wall vs left posterior wall and right anterior wall vs right posterior wall, mean ablation time (s) per lesion was 20.5 ± 8 vs 8.6 ± 3 and 12.2 ± 4 vs 9.3 ± 3; mean contact force (g): 17.1 ± 12 vs 25.4 ± 14 and 33.7 ± 13 vs 21.0 ± 11; mean AI: 547 ± 48 vs 445 ± 55 and 555 ± 56 vs 440 ± 47 (all P

AimsLeft atrial appendage electrical isolation (LAAI) may improve the rhythm outcome in selected patients with atrial fibrillation (AF). Controversy exists if LAAI is associated with an increased rate of thromboembolic complications. We sought to assess the feasibility, efficacy, and safety of interventional left atrial appendage closure (LAAC) in comparison to oral anticoagulation (OAC) after electrical LAAI.Methods and resultsWeeks after index LAAI using the cryoballoon or a linear maze like ablation strategy patients’ left atrial appendage was invasively remapped. In case of persistent LAAI, LAAC was performed. Patients who refused invasive remapping continued OAC. The primary endpoint was composed of any stroke or systemic embolism (SE) and the occurrence of intracardiac thrombus. Secondary endpoints included stroke/SE, major bleeding, and all-cause death. Of 166 patients (51% female; mean age 70 ± 8 years; mean CHAD2S2VASc score 3.4 ± 1.8) after LAAI, 94 patients received LAAC (LAAC group) and 72 continued OAC (no LAAC). After LAAC, 83% of patients received dual antiplatelet therapy for 6 weeks and aspirin thereafter. During a mean follow-up of 778 ± 630 days, 5 and 11 primary endpoint events were observed in the LAAC and no LAAC group, respectively [hazard ratio (HR) 0.27, 95% confidence interval (CI) 0.10–0.75; P = 0.010]. The calculated annual thromboembolic event rates were 6.9% (no LAAC) and 2.3% (LAAC), respectively. Left atrial appendage closure significantly reduced the incidence of stroke and SE (HR 0.31, CI 0.1–0.98; P = 0.04).ConclusionAfter electrical LAAI for rhythm control in AF patients, interventional LAAC was associated with fewer thromboembolic complications when compared with OAC.

Background The left atrial appendage (LAA) has been identified as a potential source of atrial fibrillation (AF) and has been described as the "fifth" pulmonary vein (PV). We report our initial experience in LAA isolation (LAAI) using the cryoballoon (CB) and data on durability of CB-LAAI. Methods Patients treated with a CB-LAAI were retrospectively identified. Six weeks after electrical LAAI, patients were scheduled for staged percutaneous LAA closure. During the second procedure, a subset of patients underwent invasive remapping of the LAA. Results A total of 32 patients (21 males, 68 ± 10 years old) were treated with CB-LAAI. Acute LAAI was achieved in 29 of 32 (91%) patients: single-shot LAAI was observed in 18 of 32 (56%) patients. Acute procedural sustained LAAI was related with a significantly shorter time to LAAI (sustained LAAI: 84 ± 50 s vs nonsustained LAAI: 166 ± 76 s, P = 0.004). Mean procedure and fluoroscopy time were 61 ± 29 and 8 ± 6 min, respectively. One left-sided phrenic nerve palsy occurred. In 25 of 32 (78%) patients, a second procedure for percutaneous LAA closure device implantation was performed. In 22 patients, persistency of LAAI was tested: durable LAAI was documented in 16/22 patients (73%). Conclusion In the present report, CB LAA isolation followed by staged LAA closure appeared to be safe and feasible but more data are required. Time to LAAI played a role in predicting acute sustained LAAI rate. CB LAA ablation leads to 73% of durable LAA isolation.

INTRODUCTION Interventional left atrial appendage occlusion (LAAO) has emerged as a valid alternative to oral anticoagulation (OAC) therapy for the prevention of ischemic stroke and systemic embolism in patients with non-valvular atrial fibrillation (AF). Areas covered: Antithrombotic therapy following interventional LAAO is critical in balancing the risk of thromboembolism and bleeding during the endothelialization of the implanted devices. In this article, the most recent clinical trials are reviewed and the current real-world antithrombotic strategies following LAAO device implantation are discussed. Expert commentary: For patients eligible for OAC and receiving a Watchman device, the most solid scientific evidence exists for warfarin plus aspirin for 45 days followed by dual antiplatelet therapy (DAPT) for 6 months and a lifelong aspirin therapy. In real-world most patients are being treated with DAPT for 3-6 months. Alternatively, the Watchman was approved for 3 months of novel OAC (NOAC) therapy in conjunction with aspirin. For all other devices, DAPT for 1-6 months has been used in the vast majority of cases. Considering major bleeding as the predominant complication following LAAO, evidence suggests that short-term DAPT (6 weeks) or single antiplatelet therapy using aspirin may be a viable option.

Aims We aimed to assess the feasibility, efficacy and safety of short-term dual antiplatelet therapy (DAPT) for six weeks after left atrial appendage closure (LAAC). Methods and results Data of the Cardioangiologisches Centrum Bethanien-LAAC registry were analysed. DAPT (aspirin 100 mg plus clopidogrel 75 mg) was administered until transoesophageal echocardiography (TEE) evaluation six weeks after LAAC. In the absence of significant peri-device flow or device-related thrombus (DRT), the medication was decreased to single antiplatelet therapy (SAPT). Outpatient visits were timed at six-month intervals. The incidences of major bleeding (BARC ≥3) and of thromboembolic events were investigated. A total of 298 patients (76±8 years; 62% male; CHA2DS2-VASc 4.3±1.5; HAS-BLED 3.5±1.0; 61% with history of bleeding) with successful LAAC were included. TEE revealed DRT in 7/298 (2.3%) patients (five at six-week follow-up [FU] 45±10 days after implant, two during a median long-term FU of 731 days). Non-procedure-related bleeding events occurred in 25/298 (8.4%) patients and non-procedure-related thromboembolic events in 11/298 (3.7%) patients. This translated into 3.9 bleeding events/100 patient-years and 1.7 thromboembolic events/100 patient-years, respectively. Procedure-related events consisted of major bleeding in 7/298 (2.3%) patients and stroke in 2/298 (0.7%) patients. Age ≥75 years (OR 3.2; CI: 1.2-8.0; p=0.015) and renal impairment (OR 2.5; CI: 1.1-5.7; p=0.027) were identified as independent predictors for major bleeding after LAAC. Conclusions Short-term DAPT for six weeks appears to be a viable alternative for patients after LAAC. Age ≥75 years and renal impairment increase major bleeding events threefold.

Background Left atrial appendage closure (LAAC) has been suggested as an alternative to anticoagulation in non-valvular atrial fibrillation (AF). The present study aimed to compare a LAmbre LAA occluder system [Lifetech Scientific (Shenzhen) Co. Ltd., Shenzhen, China] with the most investigated Amulet (St. Jude Medical Inc., St. Paul, MN, USA) and Watchman (Boston Scientific, Plymouth, MN, USA) devices in terms of peri-procedural and short-term outcomes. Methods This is a prospective observational study. Results Overall, 140 patients (50 female, mean age 76.2 ± 8.4 years) were consecutively enrolled. Mean CHA2DS2-VASc score was 3.8 ± 1.5, and mean HAS-BLED score was 3.9 ± 1.1. Baseline clinical characteristics were comparable between the three groups (LAmbre, n = 30; Amulet, n = 74; Watchman, n = 36); the LAmbre group had significantly more patients with complicated LAA morphology (p = 0.006). The implant success rate was 100% in LAmbre, 99% in Amulet, and 100% in Watchman group (p = 0.638). The number of device repositions was not significantly different between groups (0.7 ± 1.1 in LAmbre, 1.0 ± 2.0 in Amulet, and 1.4 ± 1.8 in Watchman group, p = 0.345). Fluoroscopic and procedural times were similar between groups. Major peri-procedural adverse events did not differ between groups (0% vs. 0% vs. 2.8%, p = 0.233). Six months’ follow-up showed good device stability and patients’ clinical condition in all groups. Conclusion LAmbre, Amulet, and Watchman exhibit remarkable implant success rate, low risk of peri-procedural adverse events, and good clinical outcomes.

BACKGROUND The incidence of pulmonary vein stenosis (PVS) after AF ablation following contemporary procedures remains unclear. We compared the incidence of PVS/narrowing (PVS/N) after PV isolation (PVI) for (1) 3-D mapping-guided wide-area encircling irrigated radiofrequency current (RFC) ablation; (2) first-third-generation big cryoballoon (CB1-3) ablation; and (3) laser balloon (LB) ablation.Methods and Results:All patients undergoing a second procedure between January 2012 and November 2016 were subgrouped according to index ablation (PVI): RFC; CB; or LB. PVS/N was classified using PV diameter ratio (second/index procedure) on selective PV angiogram performed before ablation: mild, 25-49%; moderate, 50-74%; or severe, ≥75%. A total of 344 patients (1,362 PV) were analyzed (RFC, n=211; 840 PV; CB1, n=21; 82 PV; CB2,3, n=64; 250 PV; LB, n=48; 190 PV). In the LB group, 45 patients (94%) were treated with dose ≥8.5 W. Second procedures were performed on average 14.9±14.1 months after the index procedure. Mild PVS/N was observed in 18.4%, 9.5% and 3.6% of PV in the LB, RFC and CB groups, respectively (P

The submembrane cytoskeletal meshwork of the axon contains the scaffolding protein bIV-spectrin. It provides mechanical support for the axon and anchors membrane proteins. Quivering (qv 3j ) mice lack functional bIV-spectrin and have reduced voltage-gated so- dium channel (VGSC) immunoreactivity at the axon initial segment and nodes of Ranvier. Because VGSCs are critically involved in action poten- tial generation and conduction, we hypothesized that qv 3j mice should also show functional deficits at the network level. To test this hypothe- sis, we investigated granule cell function in the dentate gyrus of anes- thetized qv 3j mice after electrical stimulation of the perforant path in vivo. This revealed an impaired input-output relationship between stimulus intensity and granule cell population spikes and an enhanced paired-pulse inhibition of population spikes, indicating a reduced ability of granule cells to generate action potentials and decreased network excitability. In contrast, the input-output curve for evoked field excita- tory postsynaptic potentials (fEPSPs) and paired-pulse facilitation of fEPSPs were unchanged, suggesting normal excitatory synaptic transmis- sion at perforant path-granule cell synapses in qv 3j mutants. To corrobo- rate our findings, we analyzed the influence of VGSC density reduction on dentate network activity using an established computational model of the dentate gyrus network. This in silico approach confirmed that the loss of VGSCs is sufficient to explain the electrophysiological changes observed in qv 3j mice. Taken together, our findings demonstrate that bIV-spectrin is required for normal granule cell firing and for physio- logical levels of network excitability in the mouse dentate gyrus in vivo. V C 2009 Wiley-Liss, Inc.