Left Atrial Appendage Electrical Isolation Research Articles

Safety and efficacy of the second-generation cryoballoon for left atrial appendage electrical isolation in canines.

Left atrial appendage electrical isolation (LAAEI) has demonstrated a significant enhancement in the success rate of atrial fibrillation (AF) ablation. Nevertheless, concerns persist about the safety of LAAEI, particularly regarding alterations in left atrial appendage (LAA) flow velocity and the potential risks of thrombus. This study aimed to assess the efficacy and safety of LAAEI, investigating changes in LAA flow velocity in canines. The study comprised a total of 10 canines. The LAAEI procedure used by a 23 mm cryoballoon of the second generation was conducted at least 180 s. Intracardiac ultrasonography (ICE) was employed to quantify the velocity flow of the LAA both prior to and following LAAEI. Following a 3-month period, subsequent evaluations were performed to assess the LAA velocity flow and the potential reconnection. Histopathological examination was conducted. Left atrial appendage electrical isolation was effectively accomplished in all canines, resulting in a 100% acute success rate (10/10). The flow velocity in the LAA showed a notable reduction during LAAEI as compared with the values before the ablation procedure (53.12 ± 5.89 vs. 42.01 ± 9.22 cm/s, P = 0.007). After the follow-up, reconnection was observed in four canines, leading to a success rate of LAAEI of 60% (6/10). The flow velocity in the LAA was consistently lower (53.12 ± 5.89 vs. 44.33 ± 10.49 cm/s, P = 0.006), and no blood clot development was observed. The histopathological study indicated that there was consistent and complete injury to the LAA, affecting all layers of its wall. The injured tissue was subsequently replaced by fibrous tissue. The feasibility of using cryoballoon ablation for LAAEI was confirmed in canines, leading to a significant reduction of LAA flow velocity after ablation. Some restoration of LAA flow velocity after ablation may be linked to the passive movement of the LAA and potential reconnecting. However, this conclusion is limited to animal study; more clinical data are needed to further illustrate the safety and accessibility of LAAEI in humans.

Electrophysiological responses of the left atrial appendage during pulsed-field electrical isolation utilizing a novel device in a canine model.

The electrophysiological responses of the left atrial appendage (LAA) during pulsed-field electrical isolation have not been established. This study aims to investigate the electrical responses of the LAA during pulsed-field electrical isolation using a novel device and their relations to acute isolation success. Six canines were enrolled. The E-SeaLA™ device, which is able to perform LAA occlusion and ablation simultaneously, was deployed into the LAA ostium. LAA potentials (LAAp) were mapped via a mapping catheter, and the LAAp recovery time (LAAp RT, the time between the last pulsed spike and the first recovered LAAp) was measured after pulsed-train delivery. The initial pulse index (PI, corelated to pulsed-field intensity) was adjusted during the ablation procedure until LAAEI was achieved. Acute LAA electrical isolation (LAAEI) success was defined as LAAp disappearance or exit and entrance conduction block, confirmed through a drug test and a 60-minute waiting period. All canines achieved successful LAA occlusion without peri-device leaks. Acute LAA electrical isolation (LAAEI) was achieved in five out of six canines (5/6, 83.3%). Very late LAAp recurrence (LAAp RT > 600 s) was observed during PFA. Early recurrence (LAAp RT < 30 s) was observed in two canines (2/6, 33.3%) post-PFA. Intermediate recurrence (LAAp RT ~ 120 s) was observed in three canines (3/6, 50%) post-PFA. The two canines with intermediate recurrence achieved LAAEI with higher PI ablations. The one canine with early LAAp recurrence had a peri-device leak and achieved LAAEI by the same PI after replacing with a larger size device and eliminating the peri-device leak. Another canine with early recurrence (1/6, 16.7%) failed to achieve LAAEI due to epicardial connection with persistent left superior vena cava. No coronary spasm, stenosis or other complications were observed. These results suggest that with proper device-tissue contact and pulse intensity, LAAEI can be achieved using this novel device without serious complications. The LAAp RT patterns observed in this study could inform and guide the adjustment of the ablation strategy.

The Strengths and Weaknesses of Left Atrial Appendage Ligation or Exclusion (LARIAT, AtriaClip, Surgical Suture)

Left atrial appendage (LAA) epicardial exclusion has been associated with addressing 2 potential deleterious consequences attributed to the LAA, namely, thrombus formation and an arrhythmogenic contributor in advanced forms of atrial fibrillation. With more than 60 years of history, the surgical exclusion of the LAA has been firmly established. Numerous approaches have been used for surgical LAA exclusion including surgical resections, suture ligation, cutting and non-cutting staples, and surgical clips. Additionally, a percutaneous epicardial LAA ligation approach has been developed. A discussion of the various epicardial LAA exclusion approaches and their efficacy will be discussed, along with the salient beneficial affects on LAA thrombus formation, LAA electrical isolation and neuroendocrine homeostasis.

PO-01-186 PERCUTANEOUS LEFT ATRIAL APPENDAGE CLOSURE AND PULSED-FIELD ISOLATION WITH A NOVEL DEVICE SYSTEM IN A CANINE MODEL: FEASIBILITY, SAFETY, ENDOTHELIALIZATION, AND LESION DURABILITY EVALUATION

Left atrial appendage (LAA) electrical isolation (LAAEI) can reduce the recurrence of atrial fibrillation in patients with LAA firing. However, LAAEI using either radiofrequency or cryoablation endured a <95% acute success rate and a further lower durability rate, with potential harm to the left phrenic nerve and left circumflex artery (LCXa). LAAEI is an independent risk factor for left atrial thrombogenesis and stroke, which can be effectively decreased by LAA closure (LAAC). To investigate the feasibility, safety, and efficiency of the percutaneous left atrial appendage closure and pulsed-field isolation with a novel device system. The E-SeaLATM device system was utilized in 18 canines: Group 1a - LAAEI with initial parameters (6 cases), Group 1b - LAAC+LAAEI with initial parameters (3 cases), Group 2a - LAAEI with optimized parameters (3 cases), and Group 2b – LAAC+LAAEI with optimized parameters (6 cases). Device position and LAAEI rate in the acute phase, and endothelialization, LAAEI durability, and stenosis of LCXa in the follow-up phase were evaluated. Acute LAAEI was achieved in all 18 canines. LAA reconnected in 8/9 cases (88.9%, at 1 week to 6 months) in Group 1, and 2/9 (22.2%, at 1-6 months) in Group 2. Full endothelialization was observed in 1/3 cases at 3 months and 6/6 at 6 months. No device displacement occurred after LAAC. No LCXa spasm or fixed stenosis was detected. Mild pericardial effusion (1-2mm) without hemodynamic influence was noticed in 2/18 (11.1%) in the acute phase, which spontaneously resolved in the follow-up phase. The novel E-SeaLATM system could effectively occlude and electrically isolated the LAA in the canine model, with full endothelialization at 6 months, and satisfactory LAAI durability using the optimized pulsed field parameters. Future studies should address feasibility, efficacy, and safety in humans.

Percutaneous left atrial appendage closure: beyond the classic indications

Percutaneous left atrial appendage closure (LAAC) has proven to be an effective alternative to oral anticoagulation (OAC) for stroke prevention in patients with non-valvular atrial fibrillation (NVAF). International guidelines traditionally recommend LAAC for NVAF patients at high thromboembolic risk and contraindication to or at high risk for OAC. However, there are many other clinical situations in which this procedure may also be beneficial. This paper discusses the potential role of LAAC in specific haemorrhagic diseases (cerebral amyloid angiopathy, age-related macular degeneration, hereditary haemorrhagic telangiectasia, and Moyamoya disease), after left atrial appendage (LAA) electrical isolation, in cases of persistent thrombus inside the LAA, in end-stage renal disease and in special groups of patients for whom low compliance and persistence to OAC may be anticipated.

Abstract 15749: Outcomes of Fluoroless vs. Fluoroscopy-Guided Left Atrial Appendage Electrical Isolation During Catheter Ablation of Atrial Fibrillation

Introduction: Fluoroscopy-guided catheter ablation remains a common practice. With the presence of technologies such as intracardiac echocardiography (ICE) and electroanatomic mapping (EAM), it is possible to perform fluoro- and lead-free procedures to avoid the hazards of prolonged radiation exposure. Left atrial appendage electrical isolation (LAAEI) is a proven e!ective ablation strategy for atrial fibrillation (AF). We sought to assess the characteristics, complications, and outcomes of fluoroscopy-guided LAAEI and compare them to fluoroless LAAEI. Methods: We retrospectively analyzed patients with AF who underwent LAAEI as part of their ablation procedure. The study group included patients who underwent LAAEI either under fluoroscopy guidance or with ICE and EAM alone. We analyzed outcomes and procedural data, including procedural times, fluoroscopy times, radiation exposure (mGy), and radiofrequency times. Results: Overall, we analyzed 168 patients who underwent LAAEI; 110 under fluoroscopy guidance and 58 fluoroless. The mean procedural time was similar in both groups (248 ± 101 vs 264 ± 83 minutes, respectively, p=0.27). The mean RF time was longer in the fluoroscopy-guided group (50 ± 28.2 compared to 43 ± 17.1 minutes, respectively, p&lt;0.001).The mean fluoroscopy time in the fluoroscopy-guided group was 25.3 ± 24.7 minutes, with mean radiation exposure of 177 ± 389 mGy. There was no difference in procedure-related complication rates ( 7 [6.3%] vs 4 [6.9%], respectively, p=0.89). At follow-up, there was no significant difference in arrhythmia recurrence rates (40.9% vs 31%, p=0.21). Conclusion: Fluoroless LAAEI is a safe and e!ective alternative to fluoroscopy-guided ablation, with the added benefit of averting the risks of ionizing radiation exposure. 1

Transesophageal Echocardiography Following Left Atrial Appendage Electrical Isolation: Diagnostic Pitfalls and Clinical Implications.

Following left atrial appendage (LAA) electrical isolation, the decision on whether to continue oral anticoagulation after successful atrial fibrillation ablation is based on the study of its mechanical function on transesophageal echocardiography (TEE). In this cohort, LAA contraction is absent and the incorrect interpretation of emptying flow velocities can lead to unwanted clinical sequelae. One hundred and sixty consecutive TEE exams performed to evaluate the LAA mechanical function following its electrical isolation were reviewed by an experienced operator blinded to the original diagnosis of LAA dysfunction. The rate of diagnostic discrepancy in the assessment LAA dysfunction and its clinical implications were evaluated. Diagnostic discrepancy with misclassification of the LAA mechanical function occurred 36% (58/160) of TEE exams. In most cases (57/58), such discrepancy was observed in the setting of an incorrect original diagnosis of a normal LAA mechanical function despite absent/reduced or inconsistent LAA contraction. This main source of this wrong diagnosis was the wrong interpretation of passive LAA flows (34/57; 60%), followed by failure to identify dissociated firing (15/57; 26%). In rare cases (8/57; 14%), velocities of surrounding structures were interpreted as LAA flow due to misplacement of the pulsed-wave Doppler sample volume. Following LAA isolation, the proportion of patients who experienced a cerebrovascular event while off oral anticoagulation due to the misclassification of their LAA mechanical function was 70% (7/10 [95% CI, 40%-89%]). Underdiagnosis of LAA mechanical dysfunction is common in TEEs performed following LAA electrical isolation, and it is associated with an increased risk of cerebrovascular events owing to oral anticoagulation discontinuation despite absent/reduced LAA contraction. Careful review of the TEE exam by an operator with specific expertise in LAA imaging and familiar with the functional implications of LAA isolation is necessary before interrupting oral anticoagulation in this cohort.

PO-696-07 LEFT ATRIAL APPENDAGE ANATOMICAL CHANGES FOLLOWING RADIOFREQUENCY-BASED OSTIAL ISOLATION

Left atrial appendage (LAA) electrical isolation (ei) may be achieved via radiofrequency (RF) energy applications at the level of the appendage ostium targeting the sites of earliest activation recorded by a mapping catheter. Notably, RF has long been used in vascular, orthopedic, and aesthetic surgery to promote thermal-induced collagen matrix contraction, fibrosis, and tissue retraction. LAA anatomical changes associated to RF-induced tissue retraction have never been reported. To quantify the anatomical changes of the LAA ostium following RF-based LAAei. Thirty-four consecutive patients requiring AF ablation with LAAei underwent transesophageal echocardiography (TEE) within 7 days before (baseline TEE) and >6 months after (follow-up TEE) ablation. The diameter of LAA orifice and landing zone were measured at 4 different views (0°, 45°, 90°, 135°). Measurements were performed by two independent reviewers blinded to the patient’s identity. Among 34 AF patients (68±7yrs, 73.5% males), the LAA morphology was classified as chicken wing in 15 (44%) patients, windsock in 10 (29%), cactus in 6 (18%), and cauliflower in 3 (9%). At baseline TEE, the mean maximum and mean minimum ostial diameters were 25±4mm and 22±4mm, respectively. The mean maximum and mean minimum diameters of the landing zone were 26±4mm and 23±3mm, respectively. On average, LAAei was achieved after 16±7 minutes of RF at a power of 45-47W. Follow-up TEE was performed 257±148 days after LAAei. The median LAA contraction velocity was 0.1 m/s (IQR: 0.04-0.18) and was significantly impaired in all patients. At follow-up TEE, the mean maximum and mean minimum ostial diameters were 19±4mm and 17±3mm, respectively. The mean maximum and mean minimum diameters of the landing zone were 20±4mm and 18±4mm, respectively. The mean relative reduction of the ostium and the landing zone was -24.4% and -22.5%, respectively. Box-Whisker plots of the maximum and minimum ostial diameters before and after LAAei are reported in Fig.1. RF led to a >20% reduction of the diameters of the ostium and the landing zone. These changes may have important implications for a successful percutaneous occlusion procedure and justify a staged approach of isolation and occlusion.

Current evidence on the safety and efficacy of combined atrial fibrillation ablation and left atrial appendage closure

Combined atrial fibrillation (AF) ablation and left atrial (LA) appendage (LAA) closure (LAAC) has been practiced for management of both the symptoms and the high stroke risk of AF. The purpose of this review is to review recent evidence regarding the combined procedure. Newly acquired long-term data of combined AF ablation and LAAC supplied satisfactory evidence on the safety and efficacy of the combined procedure. Studies also showed LA structural remodeling following combined procedure was mainly affected by sinus rhythm status post catheter ablation, not by LAAC. A cost-effectiveness study revealed that combined procedure was a cost-effective therapeutic option in symptomatic AF patients with high stroke and bleeding risk. Due to recent evidence of high incidences of LAA thrombus formation after LAA electrical isolation (LAAEI) and benefit of LAAC after LAAEI, an extended combined procedure of standard AF ablation plus LAAEI and LAAC was considered as a potential therapeutic option for persistent AF patients with high stroke risk. In conclusion, combined AF ablation and LAAC serve as a promising option for patients with symptomatic AF and high risk of stroke and/or bleeding.

B-AB17-04 ELECTROPHYSIOLOGICAL FINDINGS IN PATIENTS UNDERGOING LEFT ATRIAL APPENDAGE OCCLUSION FOLLOWING PREVIOUS ELECTRICAL ISOLATION

Left atrial appendage electrical isolation (LAA) is an important adjunctive ablation strategy in patients with nonparoxysmal atrial fibrillation. If impaired mechanical function following isolation is observed, long-term oral anticoagulation (OAC) or, as an alternative, LAA occlusion are required. Although focal electrical potentials from the LAA do not result in normalization of appendage mechanical function, they may potentially be a source of arrhythmogenic triggers. Those focal areas might be challenging to ablate after Watchman implantation. We sought to report the incidence of focal electrical potentials in patients with a previously isolated LAA and transesophageal echocardiography (TEE) evidence of severely impaired LAA mechanical function undergoing Watchman implantation. In 97 patients undergoing Watchman 2.5 and Watchman FLX implantation following LAA isolation, a circular mapping catheter (CMC) was used before occlusion to document any residual LAA electrical activity. All patients had a severely impaired LAA mechanical function at pre-procedural TEE. Of 97 patients (mean age: 71±7 years; 61.9% males), 55 (56.7%) did not display any evidence of residual LAA electrical activity. In the remaining 42 (43.3%) patients, residual electrical potentials resulting in LAA reconnection were recorded on the CMC positioned into the appendage. On average, 4.6±1.2 radiofrequency energy applications (45W, mean duration of each RFA: 14.2±3.4s) were required to re-achieve complete isolation. Subsequent Watchman implantation was successful in all patients. Focal electrical activity from the LAA was documented in more than 1/3 of our patients. Although focal electrical potentials do not result in normalization of LAA mechanical function, they may potentially act as arrhythmogenic triggers. Since it may be challenging after device implantation, assessment and ablation of those areas should be considered before Watchman deployment.

Spectral characterization and impact of stepwise ablation protocol including LAA electrical isolation on persistent AF

To study how left atrial appendage electrical isolation (LAAEI) impacts atrial dominant frequency (DF) in patients with long-standing persistent atrial fibrillation (LSPAF). LAAEI is associated with a high probability of freedom from atrial fibrillation (AF) and spectral analysis may identify high-frequency sources. How LAAEI impacts the AF dynamics and the subgroup of LSPAF patients in whom LAAEI would be most beneficial, is unclear. Twenty patients with LSPAF were included in the study. Fast Fourier transforms (FFT) were performed on atrial electrograms recorded from 13 sites in the LA and RA. The highest peak frequency was defined as DF. There was no significant difference in DF between atrial sites except for at the superior vena cava which had the lowest DF at baseline. Stepwise ablation consisting of circumferential pulmonary vein isolation and a linear ablation set of mitral isthmus and roof significantly reduced the DF within the coronary sinus (CS) (5.93 ± 0.98Hz vs. 5.09 ± 0.72Hz, p < .05) and the LA posterior wall (LApos) (6.26 ± 0.92Hz vs. 5.43 ± 0.98Hz, p < .01). LAAEI preferentially further decreased the DF at the LApos (p < .01), but not at the CS. In cases where there was<13.6% reduction in the DF of the LApos following the stepwise ablation, the addition of LAAEI was associated with an increased restoration of sinus rhythm (55%, p < .05). LAAEI in addition to stepwise ablation results in further reduction of the DF in the LApos, which is associated with acute termination of AF and favorable ablation outcome.

Left Atrial Appendage Electrical Isolation Reduces Atrial Fibrillation Recurrences: A Simulation Study.

Left Atrial Appendage Electrical Isolation Reduces Atrial Fibrillation Recurrences: A Simulation Study.

Efficacy and safety of left atrial appendage electrical isolation during catheter ablation of atrial fibrillation: an updated meta-analysis.

Left atrial appendage electrical isolation (LAAEI) has been shown to improve freedom from all-atrial arrhythmiarecurrence in patients with non-paroxysmal atrial fibrillation (AF). The aim of this study is to investigate the long-term efficacy and safety outcomes of LAAEI in patients with non-paroxysmal AF undergoing catheter ablation. A systematic review of Medline, Cochrane, and Embase was performed for clinical studies evaluating the benefit of LAAEI in non-paroxysmal AF. Nine studies with a total of 2336 patients were included (mean age: 65 ± 9 years, 63% male). All studies included patients with persistent AF, long-standing persistent AF, or both. At a mean follow-up of 40.5 months, patients who underwent LAAEI had significantly higher freedom from all-atrial arrhythmiarecurrence than patients who underwent standard ablation alone [69.3% vs. 46.4%; risk ratio (RR) 0.54; 95% confidence interval (CI) 0.42-0.69; P < 0.0001]. A 46% relative risk reduction and 22.9% absolute risk reduction in atrial-arrhythmia recurrence was noted with LAAEI. Rates of cerebral thromboembolism were not significantly different between the two groups (LAAEI 3% vs. standard ablation 1.6%, respectively; RR 1.76; 95% CI 0.61-5.04; P = 0.29). Furthermore, there was no significant difference in the acute procedural complication rates between the two groups (LAAEI 4% vs. standard ablation 3%, respectively; RR 1.29; 95% CI 0.83-2.02; P = 0.26). At long-term follow-up, LAAEI led to a significantly higher improvement in freedom from all-atrial arrhythmiarecurrence in patients with non-paroxysmal AF, when compared to standard ablation alone. Importantly, this benefit was achieved without an increased risk of acute procedural complications or cerebral thromboembolic events.

Long-Term Outcomes of Left Atrial Appendage Electrical Isolation in Patients With Nonparoxysmal Atrial Fibrillation: A Propensity Score-Matched Analysis.

Left atrial appendage electrical isolation (LAAEI) has been proposed for the treatment of nonparoxysmal atrial fibrillation (AF). The long-term clinical outcomes of this approach remain unclear. The objective of our study was to investigate the incremental benefit and safety of LAAEI in patients undergoing catheter ablation for nonparoxysmal AF. Propensity score-matched analysis was performed using a prospective registry database from 2010 to 2014. All patients in the LAAEI group were matched based on baseline characteristics, echocardiographic parameters, and procedural ablation techniques. We identified 1842 patients who underwent catheter ablation for nonparoxysmal AF. Propensity score matching yielded 1092 patients, 546 patients with LAAEI, and 546 patients without LAAEI. At 5-year follow-up, overall freedom from all-atrial arrhythmia recurrence, off-antiarrhythmic drugs, in patients who underwent LAAEI was 68.9% versus 50.2% in those who underwent standard ablation alone (P<0.001). Acute complication rates were similar between groups (LAAEI 1.3% versus non-LAAEI 0.73%, P=0.36). At 5-year follow-up, 382 (70%) patients in the LAAEI group remained on oral anticoagulation versus 217 (39.7%) in the non-LAAEI group. At 5-year follow-up, thromboembolic events occurred in 15/546 (2.75%) in the LAAEI group and 4/546 (0.73%) in the non-LAAEI group (P=0.01). No thromboembolic events occurred in either group on-oral anticoagulation. In patients who were off-oral anticoagulation, at 5-year follow-up, thromboembolic events occurred in 15/164 (9.1%) in the LAAEI group and 4/329 (1.2%) in the non-LAAEI group (P<0.001). At 5-year follow-up, LAAEI was associated with significantly higher freedom from all-atrial arrhythmia recurrence in patients with persistent and long-standing persistent AF without increasing acute procedural complication rate. In patients off-oral anticoagulation, there appears to be a higher risk of thromboembolic events in the LAAEI group.

Management of thrombus formation after electrical isolation of the left atrial appendage in patients with atrial fibrillation.

Left atrial appendage (LAA) electrical isolation (LAAEI) in addition to pulmonary vein isolation is an emerging catheter-based therapy to treat symptomatic atrial fibrillation. Previous studies found high incidences of LAA thrombus formation after LAAEI. This study sought to analyse therapeutic strategies aiming at the resolution of LAA thrombi and prevention of thromboembolism. Left atrial appendage electrical isolation was conducted via creation of left atrial linear lesions or cryoballoon ablation. Follow-up including transoesophageal echocardiography was conducted. In patients with LAA thrombus, oral anticoagulation (OAC) was adjusted until thrombus resolution was documented. Percutaneous LAA closure (LAAC) under use of a cerebral protection device was conducted in case of medically refractory LAA thrombi. Left atrial appendage thrombus was documented in 54 of 239 analysed patients who had undergone LAAEI. Thrombus resolution was documented in 39/51 patients (72.2%) with available follow-up after adjustment of OAC. Twenty-nine patients underwent LAAC and 10 patients were kept on OAC after LAAEI. No thromboembolic events or further LAA thrombi were documented after 553 ± 443 days of follow-up in these patients. Persistent LAA thrombi despite adaption of OAC was documented in 12/51 patients. One patient remained on OAC until the end of follow-up, while LAAC with a cerebral protection device was performed in 11 patients in the presence of LAA thrombus without complications. Left atrial appendage thrombus formation is common after LAAEI. Adjustment of OAC leads to LAA thrombus resolution in most patients. Left atrial appendage closure in the presence of LAA thrombi might be a feasible option in case of failed medical treatment.

A collective European experience with left atrial appendage suture ligation using the LARIAT+ device.

We report the collective European experience of percutaneous left atrial appendage (LAA) suture ligation using the recent generation LARIAT+ suture delivery device. A total of 141 patients with non-valvular atrial fibrillation and contraindication to oral anticoagulation (OAC), thrombo-embolic events despite OAC or electrical LAA isolation were enrolled at seven European hospitals to undergo LAA ligation. Patients were followed up by clinical visits and transoesophageal echocardiography (TOE) following LAA closure. Left atrial appendage ligation was completed in 138/141 patients (97.8%). Three patients did not undergo attempted deployment of the LARIAT device due to pericardial adhesion after previous epicardial ventricular tachycardia ablation (n = 1), a pericardial access-related complication (n = 1), and multiple posterior LAA lobes (n = 1). Serious 30-day procedural adverse events occurred in 4/141 patients (2.8%). There were two device-related LAA perforations (1.4%) not resulting in any corrective intervention as the LAA was completely sealed with the LARIAT. Minor adverse events occurred in 19 patients (13.5%), including two pericardial effusions due to procedure-related pericarditis requiring pericardiocentesis. Transoesophageal echocardiography was performed after LAA ligation in 103/138 patients (74.6%) after a mean of 181 ± 72 days. Complete LAA closure was documented in 100 patients (97.1%). Two patients (1.8% of patients with follow-up) experienced a transient ischaemic attack at 4 and 7 months follow-up, although there was no leak observed with TOE. There were two deaths during long-term follow-up which were both not device related. Initial experience with the LARIAT+ device demonstrates feasibility of LAA exclusion. Further larger prospective studies with longer follow-up are warranted.

Imaging Integration to Localize and Protect the Left Coronary Artery in Patients Undergoing LAAEI

This study sought to determine the distance between the anterior wall of the left atrial appendage (LAA) ostium to the left main coronary artery (LMCA) and the left circumflex artery (LCx) in patients undergoing left atrial appendage electrical isolation (LAAEI). LAAEI improves outcomes in nonparoxysmal atrial fibrillation ablation. There is a potential risk of damaging the LMCA and the LCx during LAAEI. Patients undergoing LAAEI during the period between January 1, 2017 and October 31, 2018, were included in this study. Patients underwent cardiac computed tomography prior to ablation. The position of the LAA was analyzed. The closest distances between the LMCA, its bifurcation, LCx, and the anterior wall of the LAA ostium were measured. Additionally, imaging integration was performed to localize these vessels and catheter ablation was performed at least 5mm away. A total of 74 patients (mean age: 68 ± 9.5 years; male 54%) who underwent LAAEI were included. The mean distance from the anterior wall of the LAA ostium to the LMCA was 7.88 ± 2.8mm, to the LMCA bifurcation was 9.24 ± 4.40mm, and to the LCx was 10.03 ± 4.56mm. The LCx artery was found along the LAA ostium in 98% of the cases, whereas the LMCA was found in only 48.6%. No coronary damage or vasospasm was observed after performing LAAEI. A detailed imaging integration with cardiac computed tomography, electroanatomic mapping, and CARTOSOUND reconstructions to accurately define the anatomical relationship between the LMCA and LCx and the anterior edge of the LAA ostium should be performed prior to delivering radiofrequency energy during LAAEI. Whenthedistance on cardiac computed tomography between the LAA ostium and left coronary arteries is >10mm,intraprocedural localization of these vessels may be not necessary.

Mapping and localization of the left phrenic nerve during left atrial appendage electrical isolation to avoid inadvertent injury in patients undergoing catheter ablation of atrial fibrillation

A significant role of the left atrial appendage (LAA) in the genesis of atrial fibrillation (AF) has been described. Left atrial appendage electrical isolation (LAAEI) confers substantial long-term clinical benefits. Nevertheless, the left phrenic nerve (LPN) is in the vicinity of the LAA and can be injured during radiofrequency ablation at the ostial level. The purpose of this study was to describe our experience mapping the LPN, its anatomic relationships to the LAA and alternative approaches to isolate this structure when the LPN is located at the LAA ostium. Patients undergoing LAAEI for nonparoxysmal AF were included in this study. We attempted to localize the LPN with high-output pacing (20 mA/2 ms). Cases were classified into 4 groups (distal, middle, proximal segment and unmappable) based on the position of the LPN in electroanatomic mapping in the posterior wall of the LAA. A total of 66 cases were included in this study. The LPN was mapped in the distal segment in 27 cases (40.9%); in the middle segment in 22 (33.3%); and at the proximal segment/ostium in 3 (4.5%); the LPN was unmappable in 14 cases (21.2%). In the 3 patients in whom the LPN was at the ostial level or crossing the ostium, segmental LAAEI was attempted in 2, with successful LAAEI achieved in 1 case. There was no LPN injury. LPN mapping is feasible and should be routinely performed to prevent LPN injury during LAAEI.

Safety and feasibility of combined atrial fibrillation ablation and left atrial appendage occlusion after left atrial appendage electrical isolation.

To demonstrate the feasibility of combining left atrial appendage electrical isolation (LAAEI) with left atrial appendage occlusion (LAAO) to increase efficacy of persistent/longstanding atrial fibrillation (PLAF) catheter ablation (CA) while mitigating risk of left atrial appendage (LAA) thrombus. CA for atrial fibrillation (AF) plus LAAO is safe and feasible. LAAEI may improve freedom from recurrence in PLAF but may increase LAA thrombus. We performed 42 concomitant procedures in patients with PLAF. After standard lesions, LAAEI was performed. LAAO immediately followed ablation. If 3-month transesophageal echocardiogram (TEE) was benign, oral anticoagulation (OAC) was transitioned to dual antiplatelet therapy for 3 more months. Patients were 71.1 ± 8.5years old, with CHADS2-VASc of 3.3 ± 1.1 and HAS-BLED of 2.5 ± 1.4. Twenty-eight of 42 patients (66.7%) were completely AF free over an average follow-up of 18.6 ± 8.6months. The AF-free survival estimate was 94.5% at 1year. There was no thromboembolism (TE) during the follow-up. There were six non-significant leaks acutely and six non-significant leaks at 6months. There were three device-related thrombi, although 2/3 stopped OAC prematurely. A combined procedure is feasible and effective in treating arrhythmia and stroke risk associated with PLAF. The risk of TE despite OAC after LAAEI supports simultaneous LAAO.

Stroke Risk in Patients With Atrial Fibrillation Undergoing Electrical Isolation of the Left Atrial Appendage

BackgroundLoss of contractility leading to stasis of blood flow following left atrial appendage electrical isolation (LAAEI) could lead to thrombus formation. ObjectivesThis study evaluated the incidence of thromboembolic events (TE) in post-LAAEI cases “on” and “off” oral anticoagulation (OAC). MethodsA total of 1,854 consecutive post-LAAEI patients with follow-up transesophageal echocardiography (TEE) performed in sinus rhythm at 6 months to assess left atrial appendage (LAA) function were included in this analysis. ResultsThe TEE at 6 months revealed preserved LAA velocity, contractility, and consistent A waves in 336 (18%) and abnormal parameters in the remaining 1,518 patients. In the post-ablation period, all 336 patients with preserved LAA function were off OAC. At long-term follow-up, patients with normal LAA function did not experience any stroke events. Of the 1,518 patients with abnormal LAA contractility, 1,086 remained on OAC, and the incidence of stroke/transient ischemic attack (TIA) in this population was 18 of 1,086 (1.7%), whereas the number of TE events in the off-OAC patients (n = 432) was 72 (16.7%); p < 0.001. Of the 90 patients with stroke, 84 received left atrial appendage occlusion (LAAO) devices. At median 12.4 months (interquartile range: 9.8 to 15.3 months) of device implantation, 2 (2.4%) patients were on OAC because of high stroke risk or personal preference, whereas 81 patients discontinued OAC after LAAO device implantation without any TE events. ConclusionsLAAEI is associated with a significant risk of stroke that can be effectively reduced by optimal uninterrupted OAC or LAAO devices.