Refractory Fibrillation Research Articles

Conduction system pacing and atrioventricular node ablation for atrial fibrillation - a systematic review and meta-analysis

Abstract Background/Introduction Biventricular pacing (BVP) has been shown to reduce the risk of heart failure following atrioventricular node ablation (AVNA) for the management of medically refractory atrial fibrillation (AF) when compared with conventional right ventricular pacing.[1] Conduction system pacing (CSP) is an emerging cardiac synchronization alternative to BVP[2], however, its evidence in AVNA for AF is limited. Purpose To evaluate the effect of CSP on left ventricular ejection fraction (LVEF), QRS duration (QRSd), pacing threshold and New York Heart Association (NYHA) class score following AVNA for AF. Methods We conducted a literature review of PUBMED, MEDLINE, EMBASE, Cochrane Library, and Web of Science for randomized clinical trials (RCTs) and observational studies evaluating CSP (His bundle pacing and left bundle branch pacing) post AVNA for AF. Out of 14 studies comprising 1112 patients, we conducted meta-analyses evaluating the impact of CSP on LVEF and QRS. Ten studies were pooled to assess outcomes pre- and post-implantation of CSP following AVNA. Three observational studies and one RCT were included in the meta-analysis comparing outcomes in CSP versus BVP post AVNA. Results CSP resulted in a significant QRSd reduction (-11.01 ms, 95% CI 5.07 - 16.95, p <0.01), improved LVEF (+10.28%, 95% CI 7.03 - 13.52; p <0.01) and improved NYHA score (-1.09; 95% CI -1.41 - -0.78; p <0.01) during follow-up of 6-36 months (Figure 1) from baseline (peri-implantation). There was no significant pacing threshold rise (0.11V; 95% CI -0.14 - 0.36; p= 0.39) observed during the same period. CSP was associated with statistically significant shorter QRSd (-49.81ms; 95% CI, -70.57 - -29.06; p <0.01) when compared to BVP. For LVEF, there was a statistically significant improvement of +8.96% (95% CI 2.55 - 15.37%; p <0.01) with CSP versus BVP. Limited data prohibited comparison of threshold and NYHA outcomes between CSP and BVP. Conclusion Conduction system pacing appears effective in improving baseline LVEF, QRSd and NYHA score in AVNA for AF, and may be a viable alternative to further optimising LVEF and QRSd in comparison to BVP. Further studies are required to evaluate the long-term impact and clinical outcomes of CSP in post AVNA patients.

Impact of conduction velocity in left atrium assessing with omnipolar technology in patients with atrial fibrillation

Abstract Background There is increased interest in exploring substrate of atrial fibrillation (AF) and recent studies have shown that atrial conduction velocity (CV) reflects the electrophysiological phenomena and plays key role in perpetuating AF. The novel omnipolar technology (OT) use three unipolar and two orthogonal bipolar signals allow us to analyze the voltage, activation direction, and CV independent of catheter position. Objective The purpose of the present study was to evaluate if the left atrium (LA) CV which assessed by OT predict the any atrial tachy-arrhythmia (AT) recurrence after initial AF ablation. Methods We enrolled 58 consecutive patients who underwent initial pulmonary vein isolation (PVI) for drug refractory AF. (mean age: 68.2±10.2 years old, 32 male(55.1%), 32 persistent AF(55.1%), CHADS2 score:1.6±0.6). After electrical PVI was achieved and remained in sinus rhythm, the LA was mapped with high density mapping catheter (Advisor HD Grid, Abott USA) utilizing with the novel OT combined with Ensite X system (Abott, USA). The conduction distance and conduction times were measured from the earliest activation site to the latest activation site in LA (Figure 1). Each conduction velocity in anterior, posterior, and septal area were also calculated as conduction distance divided by conduction time. The LA voltage was also measured. Results During a mean follow up period of 316±143 days, the recurrence of AT after initial PVI was observed in 9 (15.5%) patients. There were no significant differences in baseline demographics between AT recurrence and non-recurrence group (mean age:66±13.3 vs 68.5±10.5 years old P=0.66, CHADS2 score: 1.5±0.57 vs 1.68±0.62 P=0.59, proportion of persistent AF: 15.4% vs 15.5% P=0.82, LA volume: 102±35.9 vs 93.6±37.3ml P=0.63). The earliest activation site in LA were identified in 3 areas including anterior site of right pulmonary vein (51.7%), Bachmann bundle area (41.4%), and antero-septal area (6.89%) (Figure 2). In patients with AT recurrence, the CV in LA was significantly slower than those without AF recurrence(0.61±0.21 vs 0.81±0.16 m/s, P=0.036) whereas the whole LA voltage was not (1.52±0.75 vs 2.22±1.06 mv, P=0.28). The CV in each LA portion are similar between recurrence and non-recurrence AT group. (anterior:0.57±0.24 vs 0.81±0.23 m/s, P=0.18, posterior: 0.87±0.18 vs 1.2±0.49 m/s P=0.36, septal: 0.89±0.76 vs 1.15±0.39 m/s, P=0.41). Conclusion The earliest activation site in LA was varied in each case. The whole CV in LA is a predictor of AF recurrence after PVI whereas the CV of each LA portion and LA voltage was not.

Review of Atrioventricular Node Ablation Combined with Permanent His-Purkinje Conduction System Pacing in Patients with Atrial Fibrillation with Heart Failure.

With the advancement of pacing technologies, His-Purkinje conduction system pacing (HPCSP) has been increasingly recognized as superior to conventional right ventricular pacing (RVP) and biventricular pacing (BVP). This method is characterized by a series of strategies that either strengthen the native cardiac conduction system or fully preserve physical atrioventricular activation, ensuring optimal clinical outcomes. Treatment with HPCSP is divided into two pacing categories, His bundle pacing (HBP) and left bundle branch pacing (LBBP), and when combined with atrioventricular node ablation (AVNA), can significantly improve left ventricular (LV) function. It effectively prevents tachycardia and regulates ventricular rates, demonstrating its efficacy and safety across different QRS wave complex durations. Therefore, HPCSP combined with AVNA can alleviate symptoms and improve the quality of life in patients with persistent atrial fibrillation (AF) who are unresponsive to multiple radiofrequency ablation, particularly those with concomitant heart failure (HF) who are at risk of further deterioration. As a result, this "pace and ablate" strategy could become a first-line treatment for refractory AF. As a pacing modality, HBP faces challenges in achieving precise localization and tends to increase the pacing threshold. Thus, LBBP has emerged as a novel approach within HPCSP, offering lower thresholds, higher sensing amplitudes, and improved success rates, potentially making it a preferable alternative to HBP. Future large-scale, prospective, and randomized controlled studies are needed to evaluate patient selection and implantation technology, aiming to clarify the differential clinical outcomes between pacing modalities.

The Feasibility, Safety and Outcome of Very High-Power Short Duration Radiofrequency Ablation in Pulmonary Vein Isolation: A Real-World Observation Study.

Pulmonary vein isolation (PVI) ablation is the established gold standard therapy for patients with symptomatic drug refractory atrial fibrillation (AF). Advancements in radiofrequency (RF) ablation, have led to the development of the novel contact force-sensing temperature-controlled very high-power short-duration (vHPSD) RF ablation. This setting delivers 90 W for up to 4 seconds with a constant irrigation flow rate of 8 mL/min. The aim of this study was to compare procedural outcomes and safety with conventional radiofrequency ablation. An observational study was conducted with patients who underwent first time PVI ablation between August 2020 and January 2022. The cohort was divided into: (1) vHPSD ablation; (2) High-power short duration (HPSD) ablation; (3) THERMOCOOL SMARTTOUCH™ SF (STSF). The vHPSD ablation group was prospectively recruited while the HPSD and STSF group were retrospectively collected. Primary outcomes were procedural success, PVI duration, ablation duration and incidence of perioperative adverse events. Secondary outcomes were intraprocedural morphine and midazolam requirement. A total of 175 patients were included in the study with 100, 30 and 45 patients in the vHPSD, HPSD and STSF group, respectively. PVI was successfully attained in all vHPSD patients. vHPSD demonstrated significantly reduced time required for PVI and total energy application in comparison to the HPSD and STSF groups (67.7 29.7 vs. 92.9 25.7 vs. 93.6 29.1 min, p 0.0001; 9.87 4.16 vs. 33.9 7.49 vs. 36.0 10.5 min, p 0.0001, respectively). Intravenous morphine and midazolam requirement was lower in the vHPSD group compared to the HPSD and STSF groups (10.2 3.43 vs. 16.1 4.58 vs. 15.3 3.94 mg, p 0.0001; 4.04 3.24 vs. 8.63 5.22 vs. 8.58 4.72 mg, p 0.0001). One cardiac tamponade was observed in both the vHPSD and HPSD groups while the STSF group exhibited an embolic stoke and two pericardial effusions that did not require drainage. In this study, vHPSD demonstrated a comparable safety profile to the other treatment arms. Procedural duration and energy application time was substantially reduced along with sedation requirement notwithstanding the limitations of observational study design, these preliminary findings are promising with respect to periprocedural outcomes and safety of vHPSD however longitudinal outcomes will be essential to assessing the overall efficacy of this novel technology.

Safety and feasibility of zero-fluoroscopy technique in ablation-index guided pulmonary vein isolation: a prospective, single center trial

Abstract Introduction Pulmonary vein isolation (PVI) represents the cornerstone of catheter ablation procedures in patients with symptomatic paroxysmal/persistent atrial fibrillation (AF). Conventionally, PVI is performed using fluoroscopy, but it can also be performed using the zero-fluoroscopy (ZF) technique with the assistance of electroanatomical mapping systems and intracardiac ultrasound, achieving fluoroscopy-free procedures. Purpose Our study aimed to compare procedural data of ablation-index guided point-by-point radiofrequency (RF) PVI performed with non-zero-fluoroscopy (NZF) vs. ZF approaches. Methods We enrolled 100 consecutive patients undergoing PVI for antiarrhythmic drug- refractory AF in our prospective observational study. In the first 50 cases, PVI was performed using the NZF technique, and in the other 50 cases, the ZF technique was applied. Procedural time, fluoroscopy exposure, ablation parameters, and the occurrence of complications were compared between the two groups. Results Compared to the NZF group, procedural time (59.6±10.7 min vs. 74.6±13.2 min, p<0.0001) was significantly shorter in the ZF group. This difference was mainly driven by the time from puncture to the beginning of left atrial mapping, which was significantly longer in the NZF group (17 [16; 20] min vs. 31 [23; 34.5] min, p<0.001). No differences were found between the two approaches in the number of RF applications (81 [73; 103] vs. 83 [71; 91], p=0.67), total ablation energy (54986 ± 13093 Ws vs. 55500 ± 11907 Ws, p=0.48), and the left atrial dwelling time (41.5 [36; 52.5] min vs. 40.5 [35; 46], p=0.14). No complications occurred in either group. In the ZF group, complete elimination of fluoroscopy was achieved in all cases, resulting in significant differences in fluoroscopy time (0 [0; 0] sec vs. 132 [100; 160] sec, p<0.0001] and dose (0 [0; 0] mGy vs. 4.8 [4.1; 8.2] mGy, p<0.0001) compared to the NZF technique. The acute success rate was 100% in the study population, and no complications occurred during the study period. Conclusion Ablation-index guided ZF PVI is feasible and safe. Using this technique, the procedure time can be shortened besides achieving a similar acute success rate without increasing complications.

Leadless pacemaker implantation following tricuspid interventions: multicenter collaboration of feasibility and safety

Abstract Background Permanent pacing is often required following valve intervention (either surgical or percutaneous), however tricuspid interventions pose specific challenges to conventional pacing. Therefore, leadless pacemaker (LP) implantation may be the preferred strategy when permanent pacing is required after tricuspid valve intervention. Objective To report periprocedural outcomes and follow-up of patients undergoing implantation of a LP system following tricuspid valve interventions. Methods Consecutive patients with previous tricuspid valve intervention at the time of attempted implantation of a LP were included. Results Between 2019 and 2022, 40 patients underwent LP implantations following tricuspid interventions in 5 large tertiary centers. The mean age was 68.9 ± 13.7 years, and 48 % patients were male. The indication for pacing was as following: AVB in 27 (68%) patients, AF with slow ventricular response in 10 (25%) patients, and refractory rapid atrial fibrillation (AF) referred to AV junction ablation in 3 (7%) patients. Most of the patients received Micra VR (78 %). Procedure was successful in all patients. Mean procedural time of 58 ± 32 min and median fluoroscopy time of 7.5 min. Electrical parameters were within normal range (threshold: 1.35 ± 1.2 V@0.24 ms, impedance: 772 ± 245 Ohm, R-wave: 6.9 ± 5.4 mV). No acute complications were observed. During a mean follow-up of 10 months, electrical parameters remained stable, and 4 deaths were occurred (not related to the procedure). Conclusion A LP is safe and efficient option following tricuspid valve interventions.Micra LP in a patient with bioprostheticMicra LP in a patient with tricuspid rin

Multicenter retrospective evaluation of a patient-tailored electrogram-based ablation strategy using an artificial intelligence software in repeat atrial fibrillation ablation procedures

Abstract Background While pulmonary vein isolation (PVI) is the gold standard approach of treatment of atrial fibrillation (AF), the optimal strategy in case of AF recurrences for redo patients is not well established. Several studies described the usefulness of ablating in atrial regions exhibiting abnormal electrograms, i.e. spatio-temporal dispersion, during AF and an artificial intelligence (AI) electrograms (EGMs)-based software solution has been developed and validated to obtain real-time adjudications of multipolar electrograms in de novo patients. Purpose This study sought to evaluate the novel AI-EGMs-based software approach for redo-AF ablation procedures. Methods This study was a retrospective, multicentric, nonrandomized study. Patients with recurrent symptomatic AF were enrolled in 7 European centers. Redo ablation procedures were performed using the AI software and acute and long-term outcomes after ablation were evaluated. Results A total of 117 patients with refractory symptomatic AF admitted for redo procedure were included with 30% paroxysmal, 42% short-standing persistent and 28% long-standing persistent AF at the time of the redo procedure. During the index procedures, a previous PVI ablation was performed in all patients while additional ablation such as lines and EGM-based ablation was performed in 64 patients (55%). Out of 117 patients, 30 (26%) presented with structural heart disease, 61 (52%) with hypertension, 31 (26%) with a BMI >30, 16 (14%) a sleep apnea syndrome and 24 (20%) had an antiarrhythmic treatment at the time of the procedure. The average AF history was 6.54 ± 4.15 years with an average sustained duration equal to 25 ± 62 months. AI-EGMs-based AF ablation was performed in all patients and easily integrated in the physicians’ workflow during redo procedures. AF termination, i.e. AF regularization or sinus rhythm conversion, occurred in 82/117 patients (71%) with sinus rhythm conversion by ablation in 79/117 patients (68%). After a mean follow-up of 11 ± 5 months, 81% of patients were free from documented AF, with or without antiarrhythmic drugs (AADs) after one redo procedure and 60% of patients were free from any documented atrial arrhythmia, with or without AADs, after one redo procedure per patient. Furthermore, we observed that 77%, 84% and 82% of patients were free from documented AF with or without AADs in paroxysmal, short-standing and long-standing persistent AF patients respectively, and that 71%, 59% and 49% of patients were free from any documented atrial arrhythmia with or without AADs in paroxysmal, short-standing and long-standing persistent AF patients respectively. Conclusions This retrospective study reports that patient-tailored spatiotemporal dispersion ablation is a relevant and standardized approach for repeat AF ablation. This was obtained with an AI-EGMs-based software solution, which may be added to the operative workflow of redo AF procedures.

Association between left atrial wall thickness and residual potential after first-pass pulmonary vein isolation using very high-power short-duration ablation in patients with atrial fibrillation

Abstract Background In this study, we evaluated efficacy, efficiency, and safety of pulmonary vein isolation (PVI) applying vHPSD ablation strategy in patients with atrial fibrillation (AF) and explored the association between left atrial wall thickness (LAWT) and the residual potential after first-pass PVI. Methods Between April 2, 2023 and October 6, 2023, drug refractory symptomatic AF patients who underwent AF ablation using vHPSD ablation strategy with QDOT MICRO catheter were prospectively enrolled. All patients took cardiac computed tomography (CT) a day before procedure. Using CT image, LAWT map was created. PV segments were categorized into prespecified 14 segments, and LAWT of each segment, segments with residual potential (RP) after first-pass PVI and early reconnection after 20-minute waiting after PVI were evaluated. Total procedure time, ablation time for PVI, and occurrence of procedure-related complication were collected. Results A total of 40 patients were included (mean age 64 years, 45% of persistent AF). Additional ablation other than PV was performed in 48% of patients, total procedure time was 77 minutes, and total PVI time was 9.9 minutes. With vHPSD PVI, all PVs first pass isolation rate was 60%; in terms of per PV, RSPV first-pass isolation was 88%, followed by LSPV and LIPV 85%, RIPV showed lowest first-pass isolation rate, 75% (Figure A). Most common RP sites was right carina, followed by left carina (Figure A). Compared to historical comparator, vHPSD PVI showed shorter procedure time, shorter ablation time for PVI, with numerically lower but statistically comparable first-pass PVI rate (Figure B). In total 560 PV segments in 40 patients, RSPV anterior, left carina, and right carina showed higher prevalence to be thick PV segments (over 60% of patients), followed by RPSV posterior, LSPV posterior, and RIPV anterior (over 40% of patients). Looking into ablation parameter detail, mean contact force was 10g, mean temperature was 47°C, and mean impedance drop was 8.4Ω. Compared to segments without RP, segments with RP showed thicker mean left atrial wall thickness grades, lower minimum contact force, higher maximum temperature, and lower minimum impedance drop. According to the left atrial wall thickness, thick PV segments showed higher prevalence of RP after first-pass PVI with vHPSD ablation. In segments with LAWT grade 3 or more, the RP rate was 9.1%. This thickness means thicker than 1.5 to 2.0 mm of thickness (Figure C). In 10% of patients (n=4) had audible or tactile steam-pops, visible char was confirmed in 5% of patients (n=2). There were no clinical complications. Conclusion PVI using vHPSD achieved shorter procedure time, shorter ablation time for PVI, and comparable first-pass PVI rate compared to historical comparator using ablation-index guided conventional power ablation. Thick segments had higher chance to have residual potential after first-pass PVI with vHPSD.

Long-term recurrence-free survival following second-generation cryoballoon ablation for persistent atrial fibrillation: role of the autonomic nervous system

Abstract Background The cardiac autonomic nervous system (ANS) plays a pivotal role in the regulation of atrial fibrillation (AF). Cryoballon (CB)-guided pulmonary vein isolation (PVI) is an established treatment for AF. Purpose In our present study we evaluated the impact of vagal reactions (VRs), as a surrogate parameter for ANS modulation, on the long-term outcome of CB-ablation in patients with persistent AF (PERS AF). Methods Data from consecutive PERS AF patients undergoing primary CB-guided PVI for symptomatic drug refractory AF between 2013-2023 were analysed. VRs were defined as bradycardia < 40 beats/min, asystole or higher-degree atrioventricular block. Long-term follow-up data were assessed. AF-recurrence was defined as AF lasting > 30 seconds beyond a 3-month blanking period. Results A total of 250 consecutive patients (mean age 63.9±10.0 years, 30% female) were included. VRs were recorded in 61 patients (24%, mean age 64.2±13.0 years, 30% female). The mean follow-up duration amounted to 84±14 months. Within this observation period 101 patients (40%) developed AF-recurrence. Re-ablation procedures were performed in 61 patients (60%). Patients with PVI-associated VRs presented with a significantly higher estimated AF-free survival rate (log-rank p-value < 0.001) (Figure 1) and a significantly longer median AF-free survival time (75 months, interquartile range (IR) 63-92 months) compared to those without (69 months, IR 13-79 months) (p=0.002). Beyond that Kaplan-Meier plot analyses revealed significant gender differences (Figure 1). Multivariate cox regression analyses confirmed VRs (Confidence interval (CI) 0.294-0.838, Hazard Ratio (HR) 0.497, p=0.009) and male gender (CI 0.352-0.781, HR, 524, p=0.001) as independent predictors (IPs) for AF-free-survival. Conclusion CB-ablation procedure associated VRs and male gender seem to be associated with a favorable long-term outcome in PERS AF. Further studies are warranted to verify our observations.Kaplan Meier plot on long-term AF-free s

Initial clinical experience with the balloon-in-basket pulsed field ablation system: acute results of the VOLT CE mark feasibility study.

Pulsed field ablation (PFA) for the treatment of atrial fibrillation (AF) potentially offers improved safety and procedural efficiencies compared with thermal ablation. Opportunities remain to improve effective circumferential lesion delivery, safety, and workflow of first-generation PFA systems. In this study, we aim to evaluate the initial clinical experience with a balloon-in-basket, 3D integrated PFA system with a purpose-built form factor for pulmonary vein (PV) isolation. The VOLT CE Mark Study is a pre-market, prospective, multi-centre, single-arm study to evaluate the safety and effectiveness of the Volt™ PFA system for the treatment of paroxysmal (PAF) or persistent AF (PersAF). Feasibility sub-study subjects underwent phrenic nerve evaluation, endoscopy, chest computed tomography, and cerebral magnetic resonance imaging. Study endpoints were the rate of primary serious adverse event within 7 days and acute procedural effectiveness. A total of 32 subjects (age 61.6 ± 9.6 years, 65.6% male, 84.4% PAF) were enrolled and treated in the feasibility sub-study and completed a 30-day follow-up. Acute effectiveness was achieved in 99.2% (127/128) of treated PVs (96.9% of subjects, 31/32) with 23.8 ± 4.2 PFA applications/subject. Procedure, fluoroscopy, LA dwell, and transpired ablation times were 124.6 ± 28.1, 19.8 ± 8.9, 53.0 ± 21.0, and 48.0 ± 19.9 min, respectively. Systematic assessments of initial safety revealed no phrenic nerve injury, pulmonary vein stenosis, or oesophageal lesions causally related to the PFA system and three subjects with silent cerebral lesions (9.4%). There were no primary serious adverse events. The initial clinical use of the Volt PFA System demonstrates acute safety and effectiveness in the treatment of symptomatic, drug refractory AF.

"Ablate and Pace" with Conduction System Pacing: Concomitant versus Delayed Atrioventricular Junction Ablation.

Objectives: Conduction system pacing (CSP) and atrioventricular junction ablation (AVJA) improve the outcomes in patients with symptomatic, refractory atrial fibrillation (AF). In this setting, AVJA can be performed simultaneously with implantation or in a second procedure a few weeks after implantation. Comparison data on these two alternative strategies are lacking. Methods: A prospective, multicentre, observational study enrolled consecutive patients with symptomatic, refractory AF undergoing CSP and AVJA performed in a single procedure or in two separate procedures. Data on the long-term outcomes and healthcare resource utilization were prospectively collected. Results: A total of 147 patients were enrolled: for 105 patients, CSP implantation and AVJA were performed simultaneously (concomitant AVJA); in 42, AVJA was performed in a second procedure, with a mean of 28.8 ± 19.3 days from implantation (delayed AVJA). After a mean follow-up of 12 months, the rate of procedure-related complications was similar in both groups (3.8% vs. 2.4%; p = 0.666). Concomitant AVJA was associated with a lower number of procedure-related hospitalizations per patient (1.0 ± 0.1 vs. 2.0 ± 0.3; p < 0.001) and with a lower number of hospital treatment days per patient (4.7 ± 1.8 vs. 7.4 ± 1.9; p < 0.001). Conclusions: Concomitant AVJA resulted as being as safe as delayed AVJA and was associated with a lower utilization of healthcare resources.

Leadless pacemaker implantation following tricuspid interventions: multicenter collaboration of feasibility and safety.

Permanent pacing is often required following valve intervention (either surgical or percutaneous); however, tricuspid interventions pose specific challenges to conventional pacing. Therefore, leadless pacemaker (LP) implantation may be the preferred strategy when permanent pacing is required after tricuspid valve intervention. To report periprocedural outcomes and follow-up of patients undergoing implantation of a LP system following tricuspid valve interventions. Patients with previous tricuspid valve intervention at the time of attempted implantation of a LP (MicraTM, Medtronic, Minneapolis, MN, USA) were included. Between 2019 and 2022, 40 patients underwent LP implantations following tricuspid interventions in 5 large tertiary centers. The mean age was 68.9 ± 13.7years, and 48% patients were male. The indication for pacing was as following: AVB in 27 (68%) patients, AF with slow ventricular response in 10 (25%) patients, and refractory rapid atrial fibrillation (AF) referred to AV junction ablation in 3 (7%) patients. Most of the patients received Micra VR (78%). The procedure was successful in all patients. The mean procedural time is 58 ± 32min, and the median fluoroscopy time is 7.5min. Electrical parameters were within normal range (threshold: 1.35 ± 1.2V@0.24ms, impedance: 772 ± 245 Ohm, R-wave: 6.9 ± 5.4mV). No acute complications were observed. During a mean follow-up of 10months, electrical parameters remained stable, and 4 deaths were occurred (not related to the procedure). A LP is a safe and efficient option following tricuspid valve interventions.

Impact on nurse workload and patient satisfaction of atrioventricular junction ablation performed simultaneously with conduction system pacing using a superior approach from the pocket compared with the conventional femoral approach.

Conduction system pacing (CSP) and atrioventricular junction ablation (AVJA) improve outcomes in patients with symptomatic, refractory atrial fibrillation (AF). Superior approach (SA) from the pocket, via the axillary or subclavian vein, has been recently proposed as an alternative to the conventional femoral access (FA) to perform AVJA. In this study, we compare the impact of these alternative approaches on nurse workload (NWL) and patient satisfaction. This was a prospective, observational study enrolling consecutive patients undergoing simultaneous CSP and AVJA. Electrophysiology laboratory (EP Lab) NWL was calculated by using a self-developed model. Ward NWL was calculated using the MIDENF® validated scale. Patient satisfaction was collected using the Hospital Consumer Assessment of Healthcare Provider Systems questionnaire. A total of 119 patients were enrolled: in 50, AVJA was primarily attempted with SA, and in 69 with FA. Compared with FA, SA was associated with a lower EP Lab NWL (169.8 ± 26.7 vs. 202.7 ± 38.9 min; P < 0.001) and a lower Ward NWL (474.5 ± 184.8 vs. 808.6 ± 289.9 min; P < 0.001). Multivariate analysis identified SA as an independent predictor of lower EP Lab NWL [hazard ratio (HR) 4.60; P = 0.001] and of lower Ward NWL (HR 45.13; P < 0.001). Compared with FA, SA was associated with a higher patient-reported rating regarding their experience during hospital stay (P = 0.035) and the overall hospital evaluation (P = 0.026). In patients undergoing simultaneous CSP and AVJA, the use of an SA for ablation is a valid alternative to conventional FA. Compared with FA, this approach significantly reduces NWL and is associated with greater patient satisfaction. ClinicalTrials.gov: NCT03612635.

Reservoir Microneedle Patch Mitigates Postsurgical Atrial Fibrillation

AbstractOral amiodarone for 3–6 months is commonly required for the prevention and treatment of atrial fibrillation (AF) after surgical ablation of refractory AF. However, clinical data show that oral administration is likely to cause systemic toxicity, especially pulmonary fibrosis. Here, a new strategy is described for the treatment and prevention of postsurgical AF via the epicardial application of a monolithic reservoir microneedle device. These findings demonstrate that this strategy enables a sustained transport of amiodarone directly to the atrium, thereby maximizing therapeutic efficacy and minimizing systemic drug distribution. Notably, a significantly reduced drug dosage (only one dose of 6.3 mg for reservoir MNs versus a daily dose of ≈10 mg for oral administration) achieves therapeutic efficacy over a long period of 24 weeks in a rat AF model, circumventing the risks of pulmonary fibrosis associated with oral administration. This device can serve as a promising alternative to oral amiodarone, providing a robust therapeutic strategy for the prevention and treatment of postsurgical AF is antipicated.

Outcomes of pulmonary vein electrical isolation in patients younger than and older than 70 years

The objective of this study is to compare the clinical characteristics and outcomes of contemporary cohorts of patients undergoing catheter ablation for atrial fibrillation (AF), stratified by age (< 70 years and ≥ 70 years). This retrospective cohort study included patients who underwent catheter ablation for refractory AF. The minimum follow-up duration per patient was 12 months. A total of 239 patients were included in the study, with 171 (71.5%) in the < 70 years group and 68 (28.5%) in the ≥ 70 years group. The mean age of the study population was 62.4 years (SD 10.87). The < 70 years group had a mean age of 58.03 years (SD 9.71), while the ≥ 70 years group had a mean age of 73.4 years (SD 3.05). Furthermore, a higher proportion of paroxysmal AF was observed in patients < 70 years, whereas a higher proportion of persistent AF was found in patients ≥ 70 years. These differences were statistically significant. The recurrence rates after the initial ablation procedure were similar between the two groups (21.43% in the < 7 0 years group vs. 23.53% in the ≥ 70 years group, p = 0.79). Additionally, there were no significant differences in terms of complications. The < 70 years group experienced 18 complications, while the ≥ 70 years group had 5 complications (p = 0.472). The findings of this study suggest that patients aged 70 years and older who undergo their first catheter ablation procedure for AF demonstrate similar clinical outcomes compared to patients younger than 70 years.

Conversion to Sinus Rhythm in Refractory Atrial Fibrillation Patients after Atrioventricular Node Ablation with Conduction System Pacing.

"Ablate and pace" strategy is a reasonable treatment option in refractory atrial fibrillation (AF) when sinus rhythm (SR) cannot be achieved with catheter ablation or pharmacological therapy. Atrioventricular node ablation (AVNA) combined with conduction system pacing (CSP), with left bundle branch pacing (LBBP) or His bundle pacing (HBP), is gaining recognition since it offers the most physiological activation of the left ventricle. However, the incidence of conversion to SR after AVNA with CSP is not known. The purpose of the investigation was to determine the incidence of spontaneous conversion to SR and its predicting factors in patients undergoing CSP and AVNA. Consecutive refractory symptomatic AF patients undergoing AVNA with CSP at our institution between June 2018 and December 2022 were retrospectively analyzed. Twelve lead electrocardiogram (ECG) recordings were analyzed at each outpatient follow-up visit. Echocardiographic and clinical parameters were assessed at baseline and six months after the implantation. Sixty-eight patients (male 42.6%, age 71 8 years, left ventricular ejection fraction 40 15%) were included. Thirty-seven patients (54.4%) received HBP and 31 (45.6%) LBBP. During follow-up, spontaneous conversion to SR was registered in 6 patients (8.8%); 3 in the HBP group and 3 in the LBBP group. Baseline characteristics of patients who converted to SR did not differ from non-sinus rhythm (NSR) patients except for left atrial volume index (LAVI), which was significantly smaller in the SR group (45 mL/ (41-51) vs. 60 mL/ (52-75); p = 0.002). Multiple regression model confirmed an inverse association between LAVI and conversion to SR even after considering other clinically relevant covariates (odds ratio 1.273, p = 0.028). At follow-up, LAVI did not change in any group (SR: p = 0.345; NSR: p = 0.508). Improvement in New York Heart Association (NYHA) class was comparable in both groups. Spontaneous conversion to SR after AVNA combined with CSP is not uncommon, especially in patients with smaller left atria. Further studies are warranted to clarify which patients should be considered for initial dual-chamber device implantation to provide atrio-ventricular synchrony in case of SR restoration.

Novel laparoscopic renal denervation immediately reduces atrial fibrillation inducibility: a swine model study

Catheter-based approaches may have inherent limitations in achieving effective renal denervation (RDN) and treatment of atrial fibrillation (AF). This study aimed to investigate the acute effects of novel laparoscopic RDN on modulating AF inducibility using a swine model. Four and five swine were randomly allocated to the sham and RDN groups, respectively. Each swine underwent measurement of the atrial effective refractory period (AERP) and AF induction tests using burst atrial pacing before and immediately after sham or RDN procedures with and without vagal nerve stimulation (VNS). A laparoscopic RDN procedure circumferentially ablated the renal nerves round the renal arteries using radiofrequency energy. There was no significant difference in the baseline AERP between the two groups (p > 0.05). Under VNS, AERP was significantly increased by 20 ms after laparoscopic RDN (95% CI = 0–30, p = 0.004). Compared to the sham group, the RDN group showed significantly reduced AF inducibility [OR (95% CI) = 0.32 (0.13–0.76) and 0.24 (0.11–0.57) with and without VNS, respectively]. After laparoscopic RDN, the duration of inducible AF episodes was significantly shortened from 28 (10–77) s to 7 (3–11) s (p < 0.001). The novel laparoscopic RDN can immediately reduce AF inducibility in a swine model.

VCAM-1 accelerates atrial remodeling in TERT-/- mice

Abstract Background Aging, an independent risk factor for AF, could significantly increase its morbidity and mortality. The mechanism of AF in the elderly population remains to be further elucidated. Atrial remodeling is considered to be an important mechanism of atrial fibrillation. Telomerase dysfunction and telomere shortening are important signs of aging, and the relationship and mechanism between telomerase dysfunction and atrial remodeling is not very clear. Purpose This study aims to explore the mechanism of atrial remodeling caused by telomerase dysfunction. Methods The atrial electrophysiology was used to detect refractory period (ERP) and atrial fibrillation inducibility, and the epicardial electrical mapping technique was used to detect the atrial conduction velocity, direction and conduction heterogeneity to evaluate the atrial electrical remodeling. HE and Masson staining were used to evaluate atrial structural remodeling. RNA-seq analysis screened out the differential genes and corresponding pathways in each model. Results Compared with wild-type (WT) mice, a third-generation of telomerase reverse-transcriptase knockout mice (F3 TERT-/-, hereafter as TERT-/-) showed a shortened atrial ERP, increased atrial fibrillation inducibility, slowed atrial conduction velocity,change in the direction of propagation, and increased atrial fibrosis, suggesting electrical and structural remodeling in TERT-/- mice. RNA-seq revealed significant changes in cell adhesion molecules (CAMs) of TERT-/- mice compared with the WT, among which vascular adhesion molecule (VCAM-1) changed most significantly. Then, TERT-/- mice were treated with anti-VCAM-1 neutralizing antibodies, atrial electrical and structural remodeling was partially relieved compared to untreated TERT-/- mice. RNA-seq and KEGG enrichment analysis were conducted on differential genes, which were mainly concentrated on extracellular matrix (ECM)-receptor interaction. Furthermore, we found that the extracellular matrix LAMC3, Collgen1 and myofibroblast marker α-SMA were reversed in TERT-/- mice treated with anti-VCAM-1 neutralizing antibodies compared with TERT-/- mice. Conclusion VCAM-1 could accelerate the production of extracellular matrix, and ultimately lead to atrial electricity and structural remodeling, and the occurrence of atrial fibrillation in TERT-/- mice.

Abstract 15076: Long-Term Recurrence Free Survival in Second Generation Cryoballoon Ablation for Persistent Atrial Fibrillation: It’s All About the Autonomic Nervous System

Introduction: Cryoballon (CB)-guided pulmonary vein isolation (PVI) is an accepted treatment option for atrial fibrillation (AF). The cardiac autonomic nervous system (ANS) plays a crucial role in the regulation of AF. Hypothesis: ANS modulation has an impact on patients’ AF free survival following CB-ablation. The aim of this observational clinical trial was to analyze the impact of vagal reactions (VRs), as a surrogate parameter for ANS modulation, on the long-term outcome of CB-ablation in patients with persistent AF (PERS AF). Methods: Data from consecutive PERS AF patients treated with a CB-guided PVI for symptomatic drug refractory AF between 2013-2023 were analyzed. VRs were defined as bradycardia &lt; 40 beats/min, asystole or higher-degree atrioventricular block. All patients were continuously followed up in our outpatient clinic. AF-recurrence was defined as AF lasting &gt; 30 seconds beyond a 3-month blanking period. Results: A total of 250 consecutive patients (mean age 63.9 ± 10.0 years, 70% male) were included. VRs were recorded in 61 patients (24%). The mean follow-up duration amounted to 84±14 months. Within this observation period 101 patients (40%) developed AF recurrence a mean of 1.75 ± 0.80 times. Re-ablation procedures were performed in 61 patients (60%) a mean of 1.28 ± 0.55 times. Reconnected PVs were documented in 41 cases (67%). An additional substrate modification was performed in 34 procedures (42%). Patients with procedure associated VRs presented with a significantly higher estimated AF-free survival rate compared to those without (log-rank p-value=0.016) (Figure1). Multivariate analyses revealed the days to first AF recurrence following primary CB-ablation as an independent predictor for AF-free survival (CI 0.841-0.928, HR, 0.883, p&lt;0.01). Conclusions: CB-ablation procedure associated VRs seem to be associated with a favorable long-term outcome in PERS AF. Thus, our findings may influence future CB-ablation strategies.

Combination of percutaneous left appendage epicardial ligation and endo-epicardial atrial fibrillation ablation.

Atrial fibrillation (AF) is the main cause of cardioembolic stroke. In high-bleeding-risk patients, long-life anticoagulation therapy is not permitted, and left atrial appendage (LAA) closure may be considered. LAA is also a critical substrate for AF. Epicardial LAA occlusion has several advantages: LAA ligation results in a favorable electrical and structural atrial remodeling, which decreases AF recurrence. Endocardial ablation alone is not efficient for all patients, and new evidence shows better outcomes in patients affected by persistent AF after a combined hybrid endo-epicardial ablation. Considering the synergic potential of these techniques, in this case series, they were both combined in a single procedure. We describe the treatment of 5 patients referred for refractory AF ablation and LAA closure. All patients had high thrombotic and previous major hemorrhage, with relative contraindication to life-long therapy with anticoagulation. A combined procedure of LAA ligation and endo-epicardial ablation was scheduled with short-term anticoagulation. LAA closure was performed with an epicardial approach using the LARIAT system. Then, LA mapping and ablation were performed, endocardially and then epicardially.All procedures were concluded without complications.At follow-up, in all patients, transesophageal echocardiography showed the complete occlusion of the LAA; therefore, anticoagulation therapy was interrupted. All patients were asymptomatic, and in the sinus rhythm, no hemorrhage or ischemic events occurred. The combination of percutaneous LAA ligation and endo-epicardial ablation was revealed to be feasible and safe and might represent a new approach for the treatment of refractory AF in patients with indication of LAA occlusion.