Pulmonary Vein Research Articles

Comparison of the novel radiofrequency-balloon and the cryo-balloon in pulmonary vein isolation

Abstract Background Balloon catheters are often used for pulmonary vein isolation (PVI) in atrial fibrillation (AF) because of their procedural efficiency. Apart from the established cryo-balloon (CB) catheter, there is a novel multi-electrode radiofrequency balloon catheter (RFB) with 3D mapping integration available. There is currently no data regarding a direct comparison of the RFB-PVI and the CB-PVI in a matched population. Objective Aim of this study was to assess the procedural data, the safety profile, and the outcome of the RFB-PVI and the CB-PVI. Methods This prospective registry study included patients with symptomatic paroxysmal or persistent AF, who underwent first-time PVI between January 2019 and April 2023, either with the RFB or the CB. For reduction of potential confounders patients were matched in a 1:2 ratio. Results In total 171 consecutive RFB patients and 342 matched CB patients were included. The baseline characteristics were comparable. The estimated recurrence free survival after 12 months was 81.3% in the RFB group and 76.8% in the CB group (p = 0.359). Longer procedural duration (p < 0.001) and longer fluoroscopy time was observed in the RFB group (p < 0.001). Except for the left inferior pulmonary vein, the single-shot isolation rate was comparable. In the RFB group no major complications occurred. In the CB group one transient ischemic attack, one pericardial tamponade, and two persistent phrenic nerve palsies occurred. Conclusion Although longer procedural duration was observed in the RFB group, both technologies enable an efficient and a safe PVI. Despite the 3D mapping integration of the RFB, no reduction in the fluoroscopy time was seen in comparison to the CB.

Acute clinical outcomes of patients with HFpEF undergoing atrial fibrillation ablation

Abstract Aim Robust data show that atrial fibrillation (AF) ablation can improve left ventricular function and prevent cardiovascular complications in patients with heart failure and reduced ejection fraction. The effectiveness and safety of AF ablation in patients with heart failure and preserved ejection fraction (HFpEF) is less well characterized. Methods We retrospectively analyzed 785 consecutive patients with normal left ventricular function undergoing AF ablation in a high-volume center including 251 with AF and HFpEF. We compared baseline parameters, procedural details and procedural complications by heart failure status. Results Patients with HFpEF (n=251/785) were older (median age 70 years vs. 64 years; p < 0.05) and more frequently female (48.2% vs. 32.2%; p < 0.05) compared to patients without HF. Symptom severity was comparable with a median European Heart Rhythm Association score of 2 in both groups (p > 0.05). Arterial (71.7% vs. 59.7%, p < 0.05), diabetes (16.7% vs. 9.4%, p < 0.05) and dyslipidemia (41.4% vs. 27.2%, p < 0.05) were more common in patients with AF and HFpEF. Acute pulmonary vein isolation (PVI) was achieved in all patients using cryoballoon or radiofrequency energy with similar frequency in both groups (cryoballoon ablation: 37.8% vs. 41.6%; p > 0.05). A subgroup of patients in both groups additionally underwent cavotricuspid isthmus ablation for coexistent atrial flutter (26% vs. 20.7%; p > 0.05). Procedure times (119.4 ± 47.7 min vs. 120.2 ± 48.3 min; p > 0.05) and fluoroscopy times (15.8 ± 10.4 min vs. 15.5 ± 7.1 min; p > 0.05) were comparable. Overall complication rates did not differ (12.7% vs. 10.3%; p > 0.05). While the incidence of pericardial tamponades was slightly higher (2% vs. 0%), other severe and minor complications showed no significant differences, including stroke/transient ischemic attack (TIA; 0.4% vs. 0.6%), major life-threatening bleeding (0% vs. 0.2%), vascular complications (1.6% vs. 2.1%), phrenic nerve palsy (0.8% vs. 1.5%), and pulmonary vein stenosis (0.4 vs. 0%). The mean in-hospital stay for the procedure was 2 days in both groups (p > 0.05). In-hospital recurrence rates were similar (12.4% vs. 17%; p > 0.05), as was the need for electrical cardioversion before discharge (5.6% vs. 6.6%; p > 0.05). Conclusion Patients with HFpEF undergoing AF ablation were older, more frequently female, and have more comorbidities than patients without heart failure. Acute procedural success and acute complication rates appear low. These data encourage randomized evaluations of the safety and efficacy of ablation-based rhythm control therapy in patients with AF and HFpEF.

Low voltage area in the left atrial anterior wall predict Marshall-PLAN failure in patients with persistent atrial fibrillation

Abstract Background The most appropriate ablation strategy for persistent atrial fibrillation (PeAF) has not yet been determined. However, ethanol infusion of the vein of Marshall (VOM) combined with a linear set of ablation lesions (namely the Marshall-PLAN) has yielded encouraging results (1). Purpose Our study aimed at analyzing the relationship between low voltage areas (LVA) and arrhythmias recurrences in a PsAF population treated with the Marshall-PLAN. Methods we conducted a retrospective study on consecutive patients undergoing first catheter ablation (CA) for PsAF between 2021 and 2022 at our center. Pulmonary vein isolation (PVI), mitral isthmus ablation (VOM ethanol infusion, endocardial ablation and epicardial ablation in the great cardiac vein), left atrial (LA) roofline and cavo-tricuspid isthmus ablation were carried out in all the patients. Bidirectional block was validated for all the linear lesions as well as for PVI. Pre-ablation LA electroanatomic maps were built with CARTOv3 system and the PentaRay mapping catheter (minimum 3000 points). LVA were identified as areas >1cm2 (containing ≥3 neighboring points with ≤10mm distance) with bipolar voltage <0.5mV in SR and <0.24 mV in AF (2). All patients were followed for at least 12 months. Results Overall, 93 patients (69±7years, 30% female) with PsAF were included. Their left-ventricle ejection fraction and left atrial volume indexed for body surface area (LAVI) were 57% and 92±20 ml/m2. LA maps demonstrated at least one LVA in 70 subjects (75.3%). The mean relative surface of LA in which a LVA was evidenced was 8±14%. LVA were found within the anterior LA wall in 49 patients (53%), in the posterior wall in 33 patients (35.5%), in the inferior wall in 22 patients (24%), in the lateral wall in 14 patients (15.1%) and in the pulmonary vein region in 44 patients (47.3%). After 19±6 months of follow-up, 28 (30%) patients had AF recurrence. At Cox regression analysis (including LVA burden and LAVI dimensions), LVA localized within the anterior LA wall were predictive of arrhythmia recurrences (hazard ratio [HR] 2.0 [95% CI, 1.1–4.7], P=0.04). Kaplan-Meier estimates of survival free from recurrences at 20 months were 51% and 88% in patients with and without LVAs in the anterior LA wall (Log-rank 0.006). Conclusions The Marshall-PLAN led to a global AF-free survival of 70% after 19±6 months in our cohort of patients with PsAF. Importantly however, the data show that the subset of patients with LVA in the anterior LA wall (i.e., the LA region not targeted by the pre-specified ablation set here evaluated) have a 55%-only AF-free survival while that of patients without LVA in the anterior LA wall was of 88%. As a result, our study supports the relevance of atrial substrate assessment and the possibility of CA strategy optimization in the subset of patients with PsAF and LVA in the anterior LA wall (3).

Single versus double transseptal puncture for pulmonary vein isolation with radiofrequency catheter ablation for atrial fibrillation - insights from "Go for Zero Fluoroscopy" registry

Abstract Background Transseptal puncture is one of the most challenging steps in catheter ablation of atrial fibrillation (AF) because of the potential risk of complication. While single TSP reduces the puncture-related risk, double TSP simplifies the procedure (immediate signal visualization in pulmonary veins, avoidance of multiple changes of catheters through the single sheath). The purpose of this study was to analyze the impact of single versus double TSP during pulmonary vein isolation (PVI) with radiofrequency (RF) catheter ablation for AF on the fluoroscopy usage and procedure time. Methods Data reported from the international, multicenter prospective „Go For Zero Fluoroscopy Registry" performed in years 2018–2019 were analyzed. Overall 25 European electrophysiology centers from 14 countries and up to 5 operators from each center were enrolled. Only isolated PVI procedures were analyzed. Results A total data of 393 PVI RF procedures were collected from 25 centers. The median dose-area-product (DAP), fluoroscopy time and overall procedure time were: 810 (325 – 1839) cGy*cm2, 8 (4 – 14) minutes and 124 (92 – 168) minutes, respectively. Single TSP was associated with significantly higher DAP: 984 (459 – 1939) vs 667 (227 – 1469) cGy*cm2 (p=0.002), longer fluoroscopy time: 11 (6 – 19) vs 6 (3 – 11) minutes (p<0.001) and longer overall procedure time: 133 (103 – 168) vs 110 (90 – 168) minutes (p=0.003) as compared with double TSP. Single and double TSP group did not differ significantly in regards of general anesthesia usage, circular and multipolar mapping catheter use (p>0.05). However, single TSP was performed by operators with longer EP lab experience: 10 (4 – 15) vs 3 (0 – 10) years (p<0,001). Conclusions Double TSP is related with lower fluoroscopy usage and shorter overall procedure time of pulmonary vein isolation with radiofrequency catheter ablation for atrial fibrillation.

Efficacy of laser balloon left atrial roof ablation for patients with atrial fibrillation

Abstract Background The roof area ablation beyond pulmonary vein (PV) isolation (PVI) using a cryoballoon has been described as an effective therapy for patients with atrial fibrillation (AF). However, the effect of roof area ablation performed with a visually guided laser balloon (VGLB) remains to be elucidated. Purpose This study aims to investigate the efficacy of roof area ablation using VGLB. Methods A total of 325 patients with AF (paroxysmal AF=199, persistent AF=126) who underwent VGLB ablation from July 2018 to May 2022 were analyzed retrospectively. After initial circular isolation, VGLB was inflated to a larger size on both sides of superior PVs, and the isolation areas were extended to the roof portion. At the end of the procedure, left atrial (LA) voltage mapping was obtained to assess the LA roof scar area, and differential pacing was performed to confirm the complete conduction block. Our study population was divided into the PVI group (LB-PVI, n=228) and the roof line block beyond PVI group (LB-Roof, n=97). The efficacy endpoint was defined as freedom from atrial tachyarrhythmia (ATa) between months 3 and 12. Results One-year clinical follow-up could be obtained in 170 patients with LB-PVI and 81 patients with LB-Roof. The Kaplan-Meier survival curves are shown in Figure. At the end of the 12 months of follow-up, freedom from ATa was 80.8% in patients with LB-PVI and 91.2% in LB-Roof. The ATa freedom rate was significantly higher in the LB-Roof than in the LB-PVI (P=0.03). Conclusion The roof area ablation using VGLB was proved to be effective for patients with AF.The Kaplan-Meier survival curves

The new "olive strategy" for pulsed field ablation of atrial fibrillation: procedural data and early follow-up

Abstract Background Pulsed field ablation (PFA) is a new myocardial-specific ablation technology for atrial fibrillation (AF). Direct current electric energy is applied to cells and disrupts cell membranes by creating pores. Purpose The aim of this single-center study was to report procedural data and early recurrence of atrial tachyarrhythmia (ERAT) following a new PFA-based ablation strategy for pulmonary vein isolation (PVI). Methods Consecutive patients with symptomatic AF were enrolled to undergo PFA-PVI using the pentaspline catheter. A new ablation strategy was performed: In total 10 applications per pulmonary vein (PV) were delivered. In addition to the conventional four applications in flower- and four applications in basket-configuration, two applications were delivered in a smaller "olive"-configuration. ERAT was defined as any documented AF/atrial tachycardia (AT) lasting more than 30 seconds during a 90-days blanking period. Procedural and demographic data were analysed. Results 60 patients (37% female, age 67±12, 43% paroxysmal atrial fibrillation [PAF]) were included in this preliminary analysis. 239 PVs were identified, and all PVs could be isolated using solely the PFA device. All PVs were isolated with the first application. 40 applications per patient were delivered. No complications occurred. Procedure time was 30±11 min, fluoroscopy time was 6±3 min. Median follow-up time was 100 days. 20% of patients experienced an early recurrence after a median of 2 days (IQR 1-7.25; 92% AF, 8% AT). Kaplan Meier estimated freedom of AF/AT was 83.3 % at 3 months, 92.3% for PAF and 76.5% for persistent atrial fibrillation (p=0.11). Conclusions Our data show feasibility of a new ablation strategy with the pentaspline PFA-catheter. This study indicates high acute efficacy and safety. 83.3% of patients are free of AF/AT at 3 months. Longer follow-up times are needed to assess the clinical outcome and will be available at the time of presentation.

Head-to-head comparison of pulsed field ablation, very high power-short duration, cryoballoon and conventional radiofrequency ablation by LGE-MRI-based ablation lesion assessment

Abstract Background Novel concepts for pulmonary vein isolation (PVI) like pulsed field ablation (PFA) or high power-short duration ablation (HPSD) promise favourable profiles of safety and efficacy. However, clinical comparisons of ablation lesion quality are lacking. Purpose To systematically investigate lesion characteristics of novel ablation concepts, we performed a prospective head-to-head comparison between PFA, HPSD, conventional RF and latest generation cryoballoon ablation using late gadolinium enhancement (LGE)-MRI-based ablation lesion assessment. Methods This study included patients that underwent first-time PVI-only atrial fibrillation ablation - either by ablation index-guided RF ablation, cryoballoon ablation (Arctic Front Advance Pro), HPSD ablation (QDOT micro catheter, QMODE+, 90W, 4s) or PFA (Farapulse PFA system). All patients received an LGE-MRI 3 months post-ablation. LGE was quantified based on the signal intensity ratio of each voxel relative to the blood pool, applying a previously validated threshold of >1.2 to define LGE indicative of ablation-induced scarring using a dedicated software. LGE discontinuations of >3 mm were considered as gaps, and complete lesions were defined as LGE covering >90% of the peri-antral circumference of ipsilateral pulmonary vein (PV) pairs. Results Post-ablation LGE-MRIs from 120 patients were analysed (40 RF, 40 cryoballoon, 20 PFA, 20 HPSD). The proportion of complete PV-encircling LGE lesions was significantly higher with conventional RF than with cryoballoon ablation (50% vs. 34%; p=0.023). Importantly, HPSD ablation resulted in even more complete lesions than conventional RF (68%, p=0.004), whereas the proportion of complete LGE lesions was lowest with PFA (21%). Accordingly, the total number of gaps was lower with HPSD ablation (1.9 gaps/patient) compared to the other ablation concepts (conventional RF 2.7, cryoballoon 3.2, PFA 3.4 gaps/patient; p=0.034). As expected, large-area ablation with the cryoballoon (13.8 mm) and PFA (12.8 mm) single-shot devices resulted in the widest lesions. Of note, HPSD lesions were significantly wider than conventional RF lesions (11.1 mm vs. 8.9 mm; p=0.004). Conclusions HPSD ablation resulted in the most continuous lesions, translating in the lowest number of gaps. Of note, HPSD lesions were also significantly wider than conventional RF lesions, thus corroborating the concept of a shallower HPSD lesion geometry from experimental studies. Interestingly, conventional RF showed a higher proportion of complete PV-encircling lesions than cryoballoon ablation. While PFA lesions cover relatively large areas, comparable to cryoballoon ablation, lesions are more inhomogeneous. However, it remains to be determined, to what extent LGE discontinuities in PFA lesions indicate ineffective ablation or only reflect a different kind of remodeling compared to thermal ablation, which may be less detectable by LGE-MRI.

Long-term impact of multiple freezes during cryoballoon pulmonary-vein isolation on atrial arrhythmia recurrence

Abstract Background Cryoballloon pulmonary vein isolation (CryoPVI) is well established for atrial fibrillation (AF) ablation. Nevertheless, it is still important to identify possible periprocedural factors influencing its efficacy. With difficult anatomical conditions it is currently unclear whether the number of cryoballoon applications needed to achieve complete vein isolation has an impact on the long-term effectiveness of CryoPVI. Methods We prospectively analyzed AF patients who underwent first-time CryoPVI in a single center cohort between 2018-2023. The group allocation depended on the number of cryo applications until complete isolation was achieved. CryoPVI was performed in a standardized procedure. Follow-up was performed after 3, 6, 12, 18, 24 and 36 months post CryoPVI. Efficacy endpoint was the occurrence of symptomatic atrial arrhythmia. Results A total of 1170 patients were included in the study. Of these, in 610 patients received only one cryoballoon application per pulmonary vein to achieve complete isolation. Gender distribution (56.7% male vs. 43.3% male p=0.09) and AF phenotype (38.5% persistent AF vs. 61.5% paroxysmal AF, p=0.23) did not differ significantly between the two groups, patients who received only cryoballoon application were older (70.1 vs. 68.5, p=0.006) and accordingly had higher CHADS-VASc (2.86 vs. 2.62, p=0.006). After 36 months no difference in the efficacy endpoint was observed between the two groups (47.6% vs. 43.2%, p=0.53). Complications included three major access complications (0.5% vs. 0.5%) and one stroke within the first 30 days after the procedure (0.2% vs. 0.2%) in each group. No pericardial tamponade occurred. Conclusion Multiple- freezes during CryoPVI have no influence on atrial arrhythmia recurrence.

Safety and myocardio-necrosis laboratory data trend in patients undergoing atrial fibrillation catheter ablation: pulsed field ablation vs. radiofrequency ablation

Abstract Background Pulsed Field Ablation (PFA) is an innovative technology to perform atrial fibrillation (AF) catheter ablation. No form of thermal energy is used, but an irreversible electroporation mechanism that causes selective cardiomyocytes death, sparing the cells of adjacent tissues. There are few data in the literature about peri-procedural trend of myocardium-necrosis laboratory data in patients undergoing PFA versus those with radiofrequency (RF). Purpose Compare the short-term safety and the peri-procedural trend of myocardium-necrosis laboratory data in patients undergoing PFA with those undergoing standard-power (40W) RF catheter ablation. Methods 50 patients undergoing paroxysmal AF catheter ablation with pulmonary veins isolation were retrospectively enrolled, 25 treated with PFA and 25 with RF (matched for age, sex, BMI, left atrium size). The PFA protocol involved four two-second deliveries with the penta-spline catheter in the "basket" and in the "flower" configuration; about RF ablation, circular lesions were carried out at the antrum of each pulmonary vein. All patients underwent serial blood samples including troponin I (TnI, n.v. 0-50 ng/L) and CKMB (n.v 0-5 ng/mL) at time 0 and at 3, 24 and 48 post-procedure hours. Complication were evaluated at pre-discharge visit and at 3-month follow-up. Results The clinical and echocardiographic patient’s characteristics are summarized in Table 1. The TnI and CKMB baseline values were within normal range for all patients, both those treated with PFA and those treated with RF, and there were no statistically significant differences between the two group. Regarding the TnI and CKMB values temporal increase, a statistically significant increase was observed in patients treated with PFA (Table 2). The TnI percentage decrease over the 48 hours in RF-treated patients, although not statistically significant, is slower compared to patients treated with PFA. This data could be explained by considering that PFA causes acute damage (myocardiocytes necrosis by electroporation) with less inflammation and a less progressive nature, while RF causes damage with greater irritation and progression (coagulative necrosis) that may result in myocardial necrosis even in the subsequent hours. Despite evidence of greater myocardial necrosis, there were not procedural complications in those treated with PFA. Therefore, the TnI increase is indicative of selective myocardial damage, likely more antral. Conclusion The increase of myocardio-necrosis laboratory data appears to be higher using PFA compared to RF, and it is not associated with greater adverse events. The trend of the myocardio-necrosis laboratory data shows different reduction curves between PFA and RF, probably related to different ablation power source; these data will need to be re-analysed with a greater number of cases.Table 1Table 2

Role of high-density voltage map guiding parosysmal atrial fibrillation ablation

Abstract Background High-density mapping of the pulmonary vein antra has been demonstrated to improve the detection of conduction gaps in wide antral catheter ablation (WACA) approach for the treatment of paroxysmal atrial fibrillation (AF). Purpose We aimed to compare the AF recurrencies in patients treated with WACA for pulmonary veins isolation (PVI) guided by high-density bipolar voltage map (BVM) vs WACA guided by a standard 20-pole circumferential mapping catheter (CMC-20). Methods This prospective study included patients scheduled for AF ablation in a single center. In group A (85 patients) PVI was achieved with a conventional approach using CMC-20; in group B (96 patients) high density BVM was acquired by sequential multielectrode mapping through Pentaray Catheter (Biosense Webster). More than 1000 voltage points per map were acquired. Acute PVI was defined as an entrance and exit block after ≥ 20 min waiting period. In both groups WACA was perfomed using a contact force sensing catheter targeting an interlesion distance ≤6 mm and ablation index ≥400 at posterior wall and ≥550 at anterior wall. The primary endpoint was the AF recurrencies in the two groups. Results A total of 181 patients were included (mean age 64.9±10.6 years, 33.1% female): in 85 patients AF ablation was guided by CMC-20, in 96 patients AF ablation was guided by BVM; WACA PVI was achieved in all patients. There were no significant differences in the clinical characteristics of the two groups (table 1). At 12-month follow-up, AF recurrencies were significantly lower in the BVM group compared with CMC-20 group [11/96 (11.4%) vs 19/85 (22.3%) respectively, p=0.01]. Conclusions High-density BVM might increase success rate of AF ablation compared with a conventional 20-pole circumferential mapping approach.

Adherence to CLOSE protocol, high-power and low baseline generator impedance predicts durable pulmonary vein isolation

Abstract Background Atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI) is predominantly attributed to pulmonary vein reconnection (PVR). Predictors of AF recurrence were widely studied. However, data are scarce on the procedural parameters that predict chronic PVR. Aims to study the PVR rates and the predictors of PVR after initial PVI procedure. Methods We included 100 consecutive patients who underwent repeated ablation due to AF recurrence after initial PVI with the CARTO system, both procedures performed between 2018 and 2023. Results The mean age of the patients was 60 ± 12 years, 36% were female, and 44% had persistent AF. Thirty-eight patients underwent initial CLOSE-guided, and sixty-two underwent initial non-CLOSE PVI. Repeat procedure was performed 21 ± 14 months after the initial procedure. In total, PVR was found in 192 of 373 PVs (51.5%) and all PVs were isolated in 17/100 (17%) patients. Factors associated with all PVs being isolated were adherence to the CLOSE protocol (39.5% vs. 3.5%, p < 0.0001), higher delivered mean power (37.5W vs 30W, p = 0.027), presence of first-pass isolation (88.2% vs 40.4%, p = 0.0007), and lower baseline generator impedance (127.6 vs 136.6 Ω, p = 0.0027; respectively). Baseline generator impedance >130 Ω (AUC = 0.7403, sensitivity: 77.1%, specificity: 68.8%, p = 0.0032) was associated with significantly higher probability of PVR (OR = 6.757; p < 0.0001). Conclusions Our findings indicate that adherence to the CLOSE protocol, higher power setting, first-pass isolation, and baseline generator impedance <130 Ω during AF ablation improves the durability of PVI and reduces the incidence of PVR.

Electrophysiological characteristics and durability of index pulsed field ablation lesions from redo procedures for atrial arrhythmia recurrences

Abstract Background Catheter ablation for atrial fibrillation (AF) has been performed using mainly thermal energy sources (radiofrequency, cryo, or laser). Pulsed field ablation (PFA) is a novel energy with interesting safety and effectiveness demonstrated in previous preclinical and clinical trials. Purpose We sought to assess the electrophysiological characteristics and durability of PFA index procedure procedures using a pentaspline PFA catheter as assessed based on redo procedures in patients with AT/AF recurrences. Methods A total of 169 patients (paroxysmal AF (PAF), 120; persistent AF (PsAF), 49) who underwent PFA using a pentaspline PFA catheter in the index procedure from November 2021 to July 2023 were studied. Pulmonary vein isolation (PVI) was performed with PFA in all patients with additional PFA lines: i)posterolateral mitral isthmus (MI) ablation in 25, ii) posterior line in 40 patients. Twenty-seven patients (PAF, 11; PsAF, 16) had atrial arrhythmia (atrial tachycardia (AT) or AF) recurrence after a 3-month blanking period (16%). We analyzed the electrophysiological characteristics of previous PFA lesions in 18 (PAF, 8; PsAF, 10) out of 27 patients in whom an activation and voltage mapping using 3-D electroanatomical mapping system was available. Results PV reconnections were identified in 7 of 18 patients (13PVs/69PVs ,18.8%) at the PV-LA junctions and carina regions of both left PVs and right PVs, mainly at the anterior aspect of right PV carina (n=6). In 6 out of 10 redo cases, posterolateral MI line using PFA was performed in the index procedure based on our strategy for PsAF ablation. In these 6 cases with previous MI line using PFA for PsAF ablation endocardial PFA was combined with marshall vein ethanolization(Et-VOM). Additional RF endocardial ablation and in the CS was needed to achieve MI block in 2 (33%) in the index procedure. 3D mapping of redo cases showed MI line gaps in 6/6 (100%). In 3 of those patients, the clinical arrhythmia recurrence was a perimitral AT (50%). Nine of the 10 PsAF patients who underwent a redo procedure had an index procedure complete posterior line. Remapping demonstrated durable block in 7/9 (78%). One of these patients presented with a roof dependent AT diagnosed in the redo procedure. Durable posterior lines received a significantly larger number of PFA deliveries during the index procedure: 16.4±3.3 vs 10.0±2.8 respectively, p=0.041). Conclusion This study based on redo cases after PFA using a pentaspline PFA catheter shows that PFA is associated with high durability for PVI and posterior line ablation. However the durability of MI line are poor, even when combined with VOM ethanolization. Further research is needed to define the optimal number of deliveries required to achieve durable posterior line block.

A role for Local Impedance in CF guided PVI: initial results from the LOCALIZE CF Trial

Abstract Background Contact force catheters (CF) in combination with high-resolution 3D mapping are the gold standard for treatment of complex arrhythmias. Stable CF and catheter position increase both the safety and effectiveness of energy delivery. To date, local impedance (LI) is the only established parameter for real-time measure of lesion quality. Other methods tend to use surrogate parameters. Catheter ablation may be further improved by combining CF and LI. Purpose LOCALIZE CF assessed the utility of LI in addition to CF in predicting lesion durability during RF PVI procedures for paroxysmal atrial fibrillation (PAF). Methods LOCALIZE CF is an international, multicenter non-randomized trial consisting of an index PVI and invasive redo mapping procedure at 3 months. Patients (pts) with PAF underwent de novo PVI using a combined CF/LI catheter and 3D mapping system. Operators could use CF but were blinded to LI. Power settings and ablation duration were at operator discretion. PVI was performed with point-by-point circumferential ablation. The procedural endpoint was confirmation of entry block for all pulmonary veins (PV) after a 20-minute wait. Secondary endpoints included: safety events, procedural characteristics, and the correlation between LI-values and gaps. Gaps at 3-month remap were analysed by anatomical segment (8/ipsilateral PVI circle, 16/pt). Results This study enrolled 60 pts across 4 European centers, 54 pts completed 3-month remap. On average, pts (25% female) were 61 years of age, BMI 27kg/m2, LVEF 64%, LA diameter 38mm, and CHA2DS2-VASc score 1. High-power (40-45W) short duration was used by 3 of 4 sites (32 patients), with standard power (<40W) in the remainder. First pass isolation, assessed after 20min wait, was achieved in 73% of pts. Acute isolation of all PVs was achieved in all pts. At the 3-month re-map procedure, 92 of 845 segments were found to be reconnected. 3,980 point-to-point index ablations were analysed with respect to gap vs blocked segments. The median CF in gap segments was 11g compared to 13.9g in blocked segments (p<0.0001). Gap segments had significantly lower median LI drop (13Ω) than blocked segments (19Ω; p<0.001). In multivariate analysis, lesion spacing, CF and LI drop all independently predicted block. In ROC curve analysis (>9.5g CF, >20Ω LI), a model including all 3 factors had a significantly greater area under the curve than spacing and CF alone (p<0.0001). Conclusions Real-time measurements such as LI and CF are important for improving the quality and durability of ablations. While CF represents the stability of the catheter, LI reflects real-time lesion formation. The combination of both is important and may improve ablation and avoid gaps. This study suggests that CF >9.5g and LI drop >20Ω are predictors of durable lesion. Thus, LI, when used alongside CF, potentially offers a distinctive measure of ablation effectiveness, complementing the data provided by CF.

Reduced heart failure hospitalizations and improved quality of life in cardiac amyloidosis patients undergoing atrial fibrillation ablation

Abstract Background Cardiac amyloidosis (CA) has been associated with an increased risk of atrial arrhythmias and development and worsening of heart failure due to infiltration of the amyloid protein in the atrial wall. Few data exist regarding prognosis, symptoms, and quality of life after catheter ablation of atrial fibrillation in this category of patients. Objective The study evaluates the outcome of hospitalization for heart failure and quality of life in cardiac amyloidosis patients with atrial fibrillation after catheter ablation. Methods This is a study including 102 consecutive patients from two different centers with an established diagnosis of amyloidosis ATTR that underwent their first AF catheter ablation for persistent AF. They underwent pulmonary vein (PV) isolation + isolation of left atrial posterior wall and superior vena cava. Additionally, extrapulmonary triggers were identified and ablated. Post procedure, patients were followed up routinely with ECG during office visits, 7-day Holter monitor and event recorders during the first year followed by biannual checkups during the remaining part of the follow-up period. Quality of life (QoL) was measured using The Minnesota Living Heart Failure Questionnaire (MLHFQ) before Catheter ablation and after 18 months follow up; QoL was compared with T-test. Results 102 patients (mean age 72 ± 6) were included in the study. After 18 months follow up, 72 patients (70.6%) remained arrhythmia-free without antiarrhythmic drugs (Group 1), whereas 30 patients (29.4%) experienced recurrence (Group 2). In Group 1, 9 patients were hospitalized for heart failure, in contrast to 18 patients in Group 2, indicating a higher rate of heart failure hospitalizations associated with arrhythmia recurrence (p=0.02). The Quality of life in group 1 was 62 ±12 points before ablation and 63±16 points at 18 months follow up (p=0.17) while in group 2 was 68±16 points before ablation and 86±12 points at 18 months follow up (p<0.001). Conclusion Catheter ablation for AF in patients with cardiac amyloidosis is associated with reduced hospitalizations for heart failure, along with improvement in QoL.

Evaluation of left atrial function and tissue after pulmonary vein isolation - initial results of The EVALUATE-PVI STUDY

Abstract Background Pulmonary vein (PV) isolation (PVI) by catheter ablation is a well-established treatment for atrial fibrillation (AF). Currently, the direct and long-term impact of ablation injury on left atrial (LA) function and tissue is poorly understood. Purpose The aim of this study is to evaluate the acute and long-term impact of radiofrequency (RF) PVI ablation on LA function and corresponding tissue changes as assessed with cardiac magnetic resonance imaging (CMR). Methods Seventeen patients (76.5% male, 60.8±9.7 years) with AF who underwent primo RF PVI as part of the EVALUATE-PVI STUDY underwent three sequential CMR scans prior to PVI, and <72 hours and 3 months after PVI ablation. T2-weighted turbo spin echo imaging was applied to assess post-ablation edema. High-resolution three-dimensional (3D) late gadolinium-enhancement (LGE) images were acquired to study acute LA wall injury and chronic fibrosis formation. LA volume and function were derived from two-chamber and four-chamber SSFP cine images. Maximum and minimal LA volume was indexed to body surface area to compute LAVimax and LAVimin. Longitudinal LA strain was calculated using feature tracking, and subdivided into reservoir, conduit, and contractile strain. Results Acutely post-PVI, T2w images showed increased signal intensity and thickening throughout the entire LA wall. LGE images showed diffuse increased signal intensity, without distinct focal high signal intensity areas (Fig. 1). Functional assessment at this stage showed significantly reduced LA emptying fraction (EF), LA reservoir, and contractile strain compared to pre-PVI (54.8±11.1% vs. 48.5±7.9%, p=0.01; 18.6±5.6% vs. 14.6±2.0%, p<0.01; 8.5±3.5% vs. 5.2±1.8%, p<0.001, respectively), while LA conduit strain, LAVimin, and LAVimax did not differ significantly (Fig. 2). The LGE images acquired at 3 months, displayed clear, focal, high signal intensity areas surrounding the PVs. At this stage post-PVI, a significant increase in LA strain was observed (LA reservoir strain 14.6±2.0% vs. 16.9±3.5%, p<0.01; and contractile strain 5.2±1.8% vs. 6.7±2.9%, p<0.01; respectively). LAVimax was significantly reduced at 3 months compared to acutely post-PVI (Fig. 2). LAVimin and LA conduit strain did not differ between the pre- and post-PVI stages. Conclusion PVI ablation resulted in temporary reduced LA function acutely post-PVI, likely due to edema and thickening of the LA wall. At three months, LGE images revealed clearly visible increased signal intensity in the ablated segments. At this stage, LA function improved, though full recovery did not occur as evidenced by the persistent slightly reduced contractile strain, possibly due to the ablation-induced loss of LA myocardium and formation of fibrosis. The decrease in LAVimax indicates reverse remodeling as a result of the ablation.

Left atrial appendage clipping during hybrid atrial fibrillation ablation: a very long-term, single-center experience

Abstract Background/introduction Epicardial left atrial appendage (LAA) clipping is an effective strategy for stroke prophylaxis in high thromboembolic (TE) and bleeding risk patients with atrial fibrillation (AF). In addition to LAA exclusion from systemic circulation, clipping promotes concomitant appendage isolation, which might have positive impacts on arrhythmia control. Purpose The aim of this study was to report safety, success rate, and the long-term clinical outcomes of LAA clipping in a large cohort of AF patients undergoing concomitant hybrid ablation. Methods Consecutive patients undergoing hybrid AF ablation between 2013 and 2023 were enrolled. Hybrid ablation was performed in a one-step procedure consisting of thoracoscopic epicardial radiofrequency (RF) ablation followed by endocardial mapping and ablation, if needed. Ablation lesion set included pulmonary vein (PV) and posterior wall (PW) isolation, as well as RF applications to the LAA/posterolateral ridge. LAA clipping was performed via Atriclip exclusion system (Atricure, Inc., The Nederlands) after epicardial ablation. Additional endocardial lesions were performed in case of incomplete epicardial ablation or at physician’s discretion. Results A total of 130 patients were included (mean age: 65±9.4; 72.3% males); among them, 19.2% and 55.4% had persistent or long-standing persistent AF, respectively. Mean CHA2DS2-VASC and HAS-BLED were 3.1±1.1 and 2.3+-0.5. Five patients (3.8 %) had absolute contraindication to long-term oral anticoagulation, 3 (2.3%) had previous life-threatening bleeding events, 17 (13.1%) had a previous TE event. The final clip size was 35mm in 90.7% cases. Acute success was achieved in 97.7%; failure was due to LAA size (n=1), proximity to phrenic nerve (n=1), or bypass graft (n=1). One patient had incomplete occlusion due to a large secondary lobe, which required a second clip. No periprocedural complications related to clipping were documented. At a mean follow-up of 51±35 months, one (0.8%) patient had a stroke and 3 (2.3%) a transient ischemic attack (4 events per 552 patient/years; 0.7%). One patient had a microreentrant tachycardia mapped from the area near the LAA clipping. Conclusion In a large cohort undergoing hybrid AF ablation, epicardial LAA clipping was safe and highly successful. Acute failure was rare and due to LAA morphology or proximity to phrenic nerve and bypass graft. Thromboembolic event rate was very low.

Prophylactic administration of glycopyrrolate prevents vasovagal responses induced by pulsed field ablation in patients with atrial fibrillation

Abstract Background The FarapulseTM system was the first pulsed field ablation device to receive regulatory approval. Vagal Responses (VR) during pulmonary vein isolation (PVI) with this pentaspline device are frequent and often require back-up pacing or the administration of parasympathetic drugs. Glycopirrolate (GLY) is a medication of the muscarinic anticholinergic group; its efficacy for VR prevention when administered prophylactically before PVI has never been reported. Objective To evaluate the effectiveness of prophylactic intravenous administration of GLY on VRs induced by PFA. Methods Consecutive AF patients undergoing first-time PVI with PFA via the FarapulseTM system between April and October 2023 were prospectively enrolled in 3 European centers. Prophylactic administration of GLY (0.2 mg intravenous administration before femoral vein puncture) [Group GLY(+)] was adopted based on operator’s preference. VR was defined as at least one of the following: sinus bradycardia (<40 beats/min), asystole (>6 sec), or atrioventricular block (AVB) occurring immediately after a pulsed electric field application. VRs and maximum pause duration (maximum RR interval) were determined for each PV. Temporary backup pacing was performed as per the operator's preference. Results We enrolled 141 patients [GLY(+): 64 patients; GLY(-): 77 patients] undergoing PVI with the pentaspline FarapulseTM system. Median age was 54.1 years (54.1- 70), and 76 (54%) patients were males with an average CHA2DS2-VASc Score of 1.0 (0 – 2). A total of 563 PVs, including 3 left common PVs and 2 accessory middle PVs, were successfully isolated with the FarapulseTM PFA system. There were no statistically significant differences in baseline and procedural characteristics between two groups. VRs during PVI occurred in a total of 53 (37.6%) patients. GLY administration reduced significantly the incidence of any VRs (4.7% vs 64.9%; p<0.001) (Figure 1A). Additionally, GLY resulted in a lower incidence of VRs during LSPV (4.7% vs 62.3%; p<0.001) and LIPV (1.6% vs 9.1%; p<0.001) (Figure 1B) isolation and the need for temporary backup pacing during LSPV (24.7% vs 1.6%; p<0.001) isolation. Maximum pause duration was significantly shorter in the GLY(+) group after PFA of LSPV (1195 vs 3459 sec; p<0.001), LIPV (1128 vs 1556 sec; p<0.001), RSPV (1138 vs 1607 sec; p<0.001) and RIPV (1103 vs 1343 sec; p<0.001) compared to GLY(-) group (Figure 1C). Conclusions Glycopyrrolate is highly effective in the prevention of VRs induced by PFA ablation in AF patients undergoing first-time PVI.Figure 1

Optimizing ablation sites in recurrent atrial fibrillation cases: a novel approach using emphasize settings

Abstract Backgrounds Although catheter ablation techniques for atrial fibrillation (AF) have advanced, a certain number of cases of re-conduction after pulmonary vein isolation (PVI) still exist and are the most common cause of recurrence of atrial tachyarrhythmias. In some cases, the diversity of anatomical wall thickness and fiber orientation around the PVs might contribute to re-conduction. Identification of optimal target ablation site of re-conduction could reduce unnecessary ablation and decrease the risk of complications. However, in cases where local electrograms consisted with far filed and near filed potentials were coexist, conventional activation mapping with bipolar electrograms sometimes fails to identify the re-conduction sites. Purpose We investigated the utility of using the Emphasize settings in the emphasis map obtained by combining activation mapping and peak frequency mapping in the EnSite X system to determine the optimal ablation sites compared to the conventional map based on the activation mapping. Methods Patients undergoing AF ablation of PVI with the EnSite X system who had recurrent cases or had PVI re-conduction at the initial ablation were included. We retrospectively analyzed the cases from January 2022 to November 2023. In all cases, bipolar voltage and activation maps for left atrium and PVs were obtained by a 16-pole grid catheter (Advisor HD Grid) during atrial pacing or sinus rhythm. Local activation timing and peak frequency maps of the left atrium were performed to obtain the Emphasize settings indicating the optimal ablation sites (E-group). The Emphasize settings obtained from the maps were adjusted to make the site of re-conduction most apparent (Figures). Another group determined the ablation sites based on the activation mapping (A-group). The clinical backgrounds, laboratory data, and echocardiography data were also evaluated. Intravenous administration of ATP was performed in all targeted PVs after successful re-isolation of PVs. Results Total 44 patients (69±10 years, 32 males) and 90 PVs were found to be re-conducted and analyzed. The gaps of 34 and 40 points of PVI were observed in the E-group and C-group, respectively. The number of needs for the ablation points to successful elimination of gap was markedly smaller in the E-group (1.3±0.7 vs. 6.2±3.2, p<0.001). The optimal Emphasize settings was 340 ±75 Hz in the E-group. None of the cases showed dormant conductions by ATP administration in both groups. There were no differences in age, gender, left atrial volume index, left ventricular ejection fraction, serum creatinine levels, and N-terminal pro-brain natriuretic peptide levels between the two groups. Conclusion The optimal ablation site was visualized by adjusting the Emphasize settings, and the number of ablation points to re-isolation of PV might be markedly reduced.

Revealing intracavitary catheter positions: artificial intelligence-enhanced localization with an electrogram-driven variational autoencoder model

Abstract Background The acquisition of electroanatomical (EA) maps in clinical electrophysiology procedures typically depends on locating intracardiac mapping catheters through magnetic triangulation with external patches placed on the patient's skin. However, this configuration is hampered by shifts in the reference system if the patient moves or if the setup changes during the procedure. Leveraging the feature extraction capabilities of artificial intelligence models, it becomes possible to assess catheter positions within the atria solely based on the information encoded in intracavitary electrograms (EGMs). Consequently, a neural network model could serve as an alternative or complementary system for locating EA mapping catheters, eliminating the need for external reference patches. Purpose We aimed to create a deep learning model utilizing a disentangled variational autoencoder (d-VAE) and unipolar EGM signals. The goal was to extract the precise position of a multi-electrode catheter within the left atrium and predict the specific atrial region in which it is situated, relying solely on the information derived from unipolar EGMs. Methods The model was trained using data from 51 patients with persistent atrial fibrillation who underwent pulmonary vein ablation. We exported 3D EA maps obtained with a 20-pole multi-electrode catheter, comprising a total of 40,000 unipolar EGMs with a duration of 30 seconds. Atrial geometries were segmented into 12 different areas (refer to the Figure). Subsequently, the d-VAE model was trained with unipolar EGMs to acquire encoded features, which were then input into a classifier model. The classifier was combined with atrial positions using one-hot encodings as the ground truth. The optimal architecture was selected through a grid search involving different layer numbers, sizes, and fine-tuning. For the encoding part, we assessed the negative evidence lower bound (ELBO) and Pearson’s correlation. Regarding the classifier, we evaluated accuracy, extended accuracy (indicating accuracy in predicting the region or an adjacent one), and the area under the curve (AUC). Results The best-performing autoencoder architecture presented a negative ELBO of -0.087 and a Pearson’s correlation of 0.971; and the classifier obtained an accuracy of 38.1%, an extended accuracy of 75.2%, and an AUC of 0.814. Conclusion We introduced an alternative method for localizing intracardiac catheters within the atrial chambers based on deep-learning techniques. In contrast to traditional hardware technologies, our proposed method eliminates the need for external magnetic or impedance reference patches. This approach is not limited to AF and can be extended to other supra-ventricular procedures. The results of our proposed method are promising, suggesting potential advancements in alternative systems for locating intracardiac catheters to complement existing classical hardware methods in the future.Variational autoencoder architecture

Posterior wall isolation in patients with persistent atrial fibrillation: a single center comparative study between ablation index and very high power short duration radiofrequency ablation protocol

Abstract Background Circumferential pulmonary veins ablation (CPVA) with posterior wall isolation (PWI) using radiofrequency catheter ablation (RFCA) is gaining increasing interest in terms of safety and efficacy. Purpose To compare procedural data and efficacy between two radiofrequency ablation protocols for the treatment of persistent atrial fibrillation (PersAF): very high power-short duration (vHPSD) ablation using a novel temperature-controlled ablation catheter and Ablation Index (AI) guided RFCA using traditional contact-force catheter. Methods This single center prospective study enrolled 75 consecutive patients (Group 1) with symptomatic PersAF undergoing RFCA using a novel contact-force catheter optimized for temperature-controlled ablation with microelectrodes and 6 thermocouples for real-time temperature monitoring during ablation. The vHPSD algorithm modulates power to maintain target temperature during these lesions (90 Watts, 4 s) in the posterior wall. RF delivery in anterior regions was performed in a temperature guided setting (1-45W, 45°C) to achieve a 500-550 AI. These patients were compared to 75 propensity matched patients (Group 2) undergoing PersAF ablation with traditional AI-guided ablation. Procedural data were compared between the two groups (Table 1). Procedural outcome was considered as loop recorder documented atrial arrhythmias recurrences and compared between the two groups. Results Seventy-five patients (69% male, 63.1±11.2 years old) underwent ablation with vHPSD protocol (Group 1). CPVA and PWI was achieved in all patients with total procedure and fluoroscopy times of 67.5±28.8 min and 4.5±2.8 min, respectively. After 12-month median follow-up, 57/75 patients (76%) were free from AF. Seventy-five propensity matched patients (69% male, 60.7±9.9 years old) have undergone ablation with standard contact-force catheter. CPVA and PWI was achieved in all patients with total procedure and fluoroscopy times of 81.99±20.5 min and 5.7±2.1 min, respectively. After 12-month median follow-up, 55/75 patients (73%) were free from AF. Procedural and fluoroscopy times were significantly lower in in Group 1 than in Group 2 (Table 1). AF recurrencies were comparable between the two groups as assessed with survival analysis (Figure 1, log-rank 0.509). There were no deaths or other severe periprocedural complications. Conclusions PWI on top of CPVA is effective in limiting arrhythmic recurrences following RFCA of PersAF. Compared to standard AI guided ablation, vHPSD protocol significantly reduces procedural time and fluoroscopy exposure. Clinical outcomes between the two protocols are similar.Figure 1