Pulmonary Vein Antrum Research Articles

Risk of complications in patients undergoing pulmonary vein antrum isolation: a single centre experience

Abstract Background Pulmonary vein antrum isolation (PVAI) is the gold standard approach to treat symptomatic atrial fibrillation (AF) refractory to medical therapy. While PVAI may result in a number of potential complications, there is a growing body of literature supporting safety of same day discharge post-PVAI. Purpose To retrospectively evaluate the incidence of post-procedure acute adverse events (AE), and elucidate factors associated with increased risk of such complications in patients undergoing PVAI. Methods Patients underwent PVAI between 2004-2021 at a tertiary care centre, and were followed-up at 3, 6 and 12 months post-PVAI. All procedures were performed utilizing intra-cardiac echocardiography. Baseline characteristics of patients who experienced acute AE were compared with those in patients who did not. Univariate and multivariate logistic regression models adjusted for age, sex, type of AF, left atrial size, and comorbidities were employed to evaluate risk factors for acute AE. Results 2829 patients (mean age: 61.5±10.4 years, 33.7% female, 64.1% paroxysmal AF) were included in this study. Overall incidence of acute AE was 92 (3.3%), which included: 60 (2.1%) patients with access site hematoma, 20 (0.7%) patients with hematoma requiring treatment, and 12 (0.4%) patients with cardiac tamponade. Other complications included: 5 (0.18%) strokes or transient ischemic attacks (TIA), 3 (0.10%) esophageal fistulas, and 1 (0.03%) phrenic nerve injury. Females (4.2% vs 2%, P=0.001), patients older than 75 years (3.3% vs 2.7%, P=0.8), non-paroxysmal AF (3.4% vs 2.4%, P=0.1), body mass index ≥ 35 kg/m2 (3.6% vs 2.7%, p=0.04), those with an implanted device (6.7% vs 2.3%, p=0.004), and sinus node dysfunction (SND) (6.6% vs 2.5%, p=0.001) had a greater rate of acute AEs. Patients with comorbidities, including hypertension (3.4% vs 2%, P=0.04), Type 2 diabetes ( 3.2% vs 2.7%, p=0.7), congestive heart failure (5.6% vs 2.5%, P=0.008), and coronary artery disease (3.9% vs 2.6%, p=0.1) also manifested higher rate of acute AE. In the multivariate logistic regression model, female sex (OR= 2.5 [1.4, 4.4]), CHF (OR= 2.6 [1.3, 4.9]) and SND (OR=2.6 [1.1, 5.5] were associated with increased AE risk when adjusted for age, AF type, and other comorbidities. Conclusion In the multivariate model, female sex, a history of congestive heart failure, and SND were independently associated with a greater risk of AE following PVAI.

Revisiting pulmonary vein stenosis after high-power short-duration radiofrequency ablation in patients with atrial fibrillation

Abstract Background High-power short-duration atrial fibrillation catheter ablation (HPSD-AFCA) of pulmonary vein (PV) isolation reduces the procedure time without a difference in the efficacy as compared to conventional power AFCA (ConvP-AFCA). PV stenosis (PVS) after AFCA is a rare complication. Purpose We compared the frequency of symptomatic PVS as a long-term complication between the ConvP-AFCA and HPSD-AFCA groups. Methods We included 3,851 patients undergoing AFCA between 2009 and 2022 prospectively. We evaluated the characteristics of patients diagnosed with clinically symptomatic PVS, ascertained using computed tomography during the follow-up period. The risk of PVS was compared between the ConvP-AFCA and HPSD-AFCA groups using propensity overlap weighting. Results Symptomatic PVS was diagnosed in 14 (0.4%) patients at a mean of 342.9 days after the procedure. After overlap weighting, PVS was significantly more frequent in the HPSD-AFCA group (incidence: HPSD-AFCA, 0.8% vs. ConvP-AFCA, 0.2%; weighted hazard ratio [HR] 6.27, 95% confidence interval [CI] 2.15-18.28; P<0.001). In the multivariable Cox regression analyses, repeat AFCA procedures (HR 3.52, 95% CI 1.18-10.55; P=0.024) and paroxysmal AF (HR 8.29, 95% CI 1.08-63.82; P=0.042) were also independently associated with PVS after AFCA. Among the PVs of patients with PVS, stenotic PVs had shorter antral diameters and a smaller cross-sectional area than non-stenotic PVs on preprocedural computed tomographic evaluations. Conclusion HPSD-AFCA, compared to ConvP-AFCA, was associated with a 6-fold increased risk of symptomatic PVS. Caution is required, especially in patients with plans for a repeated AFCA, paroxysmal AF, or small PV antrum.

Efficacy of Vein of Marshall Ethanol Infusion Added to Left Atrial Anatomical Ablation for Treatment of Persistent Atrial Fibrillation in Patients with Hypertrophic Cardiomyopathy.

Radiofrequency catheter ablation (RFCA) has been shown to have low efficacy for the treatment of persistent atrial fibrillation (AF) in patients with hypertrophic cardiomyopathy (HCM). We conducted this study to evaluate the benefit of adjunctive vein of Marshall (VOM) ethanol infusion during RFCA for persistent AF (PsAF) in patients with non-obstructive HCM. This multicenter retrospective observational study included 102 consecutive non-obstructive HCM patients with PsAF who underwent RFCA plus VOM ethanol infusion (VOM-EI) (RFCA + VOM, n = 56) or RFCA alone (RFCA, n = 46) for the first time. The efficacy endpoint was survival without AF or atrial tachycardia (AT) after the blanking period. We completed the VOM-EI in 92.9% (52/56) patients. The left pulmonary vein antrum ablation time (RFCA + VOM: 19.9 6.1 min vs. RFCA: 27.2 9.3 min), mitral isthmus (MI) ablation time (RFCA + VOM: 16.9 3.7 min vs. RFCA: 28.4 7.8 min), and rate of coronary sinus (CS) vein ablation (RFCA + VOM: 57.69% vs. RFCA: 80.43%) were lower but the acute success rate of MI block (RFCA + VOM: 98.1% vs. RFCA: 84.8%) were higher in the RFCA + VOM group than those in the RFCA group (all p 0.05). After twelve months follow-up, 84.6% of patients (44/52) survived without AF/AT in the RFCA + VOM group, compared to 65.2% of patients (30/46) in the RFCA group (p = 0.03; odds ratio = 2.93, 95% CI: 1.18-7.79). VOM-EI combined with RFCA decreased the recurrence rate of AF/AT at 12 months in HCM patients with PsAF. VOM-EI simplified the ablation of the left pulmonary vein antrum and MI and increased the success rate of MI bidirectional block.

Modification of the pulmonary vein antrum is associated with recurrence after durable pulmonary vein isolation for paroxysmal atrial fibrillation.

Although previous studies have shown the isolated areas after pulmonary vein isolation (PVI) using cryoballoons (CB) (CB-PVI), no studies have investigated the association between the isolated area and recurrence of atrial fibrillation (AF) and atrial tachycardia (AT). This single-center observational study investigated the association between the ablated area and recurrence rate after durable CB-PVI for paroxysmal AF. This study included 76 patients with paroxysmal AF who underwent CB-PVI and established durable PVI with a second procedure, regardless of AF/AT recurrence, 6months after the first procedure. To compare the ablated zones, we quantified the left- and right-sided PV antral isolation areas and non-ablated posterior wall (PW) area. We examined non-ablated areas of the PW and AF/AT recurrence in the chronic phase. In total, 16 of the 76 patients had AF/AT recurrence. The mean follow-up duration was 34months. The non-ablated PW area (14.0 ± 4.6 cm2 vs. 11.5 ± 3.7 cm2; p = 0.0213) and the ratio of the non-ablated PW area to the whole PW area (NAPW) (52.9 ± 9.1% vs. 44.8 ± 9.8%; p = 0.003) were significantly higher in the AF/AT recurrence group than in the AF/AT non-recurrence group. NAPW > 50% was an independent predictor of AF/AT recurrence. The NAPW after durable CB-PVI is associated with AF/AT recurrence. PW isolation or additional applications on the PV antrum with cryoballoon may be considered in addition to PVI in paroxysmal AF, especially in patients with dilated left atria.

Early lesion visualization after catheter ablation for atrial fibrillation: rationale and preliminary results of the CALAMARI study

Abstract Funding Acknowledgements Type of funding sources: None. Background Incomplete atrial lesion is related to high atrial fibrillation (AF) recurrence after Pulmonary vein antrum isolation (PVAI). Objectives The CALAMARI study is a single-center, prospective, observational study with a longitudinal design. The primary aim is to assess PVAI lesion and its development over time using cardiovascular magnetic resonance (CMR). The secondary objective is to identify possible predictors of AF recurrence. Methods 96 consecutive patients undergoing PVAI for paroxysmal AF will undergo four sequential CMR: 1) pre-PVAI CMR 2) post-PVAI CMR, immediately after the ablation 3) CMR one-day or one-week post-PVAI 4) CMR 3-months post-PVAI. Dark-blood short-inversion-time recovery (DB-STIR) will identify oedema. Pre- and post-contrast prepped inversion-recovery with long inversion time (IR-prep) and three-dimensional late gadolinium enhancement (3D-LGE) images will be used to visualize atrial lesion (AL). Qualitative and quantitative assessments of AL will be performed. Patients will be followed-up for 2 years to identify AF recurrence. Preliminary results Ten patients (63.1±5.7 years old, 80% male) completed a pre-PVAI CMR and a post-PVAI-CMR. The AL post-PVAI was visible in 9 patients (90%) using post-contrast IR-prep sequences and in 6 patients (60%) using pre-contrast IR-prep and 3D-LGE. Microvascular obstruction was identified in 7 (70%) patients using IR-prep-post-contrast. On DB-STIR, edema was visualized in all patients with a significant increase in the left atrium wall thickening in CMR post-PVAI vs. pre-PVAI CMR (6.4±2.9 vs. 3.4±1.5, p = 0.09). Conclusion Post-PVAI AL visualization with CMR is feasible in most patients. The CALAMARI study will better understand the AL modifications over time.

Role of diagnosis-to-ablation time in paroxysmal atrial fibrillation: preliminary results of the MULTI AF trial

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Diagnosis-to-ablation time (DAT) has been already defined as a predictor of atrial fibrillation (AF) ablation outcome. AF promotes pathological atrial remodelling at electrical, cellular, and structural levels. The aims of this study were to determine the role of DAT in atrial electrical remodelling and its impact on AF recurrencies. Methods Between January 2020 and February 2022, 122 patients (62% male, age 63.5±10.8 y) underwent pulmonary veins isolation (PVI) for paroxysmal atrial fibrillation in 7 Italian centres. For each patient, a high-density bipolar voltage map (BVM) of the left atrium (LA) was acquired by sequential multielectrode mapping in sinus rhythm through the Pentaray™ Catheter and the CARTO3® mapping system. More than 200 voltage points per map were acquired in different segments of the LA (posterior, anterior, lateral, superior, septal and inferior ). The procedural endpoint was PVI by circumferential ablation around the pulmonary vein antra. On top of PVI no "adjunctive" ablations, were performed. All patients were monitored as outpatients for AF recurrence. Results For the 122 patients enrolled the mean DAT was 37.6±35.2 months. Two groups were identified according to DAT: 51 patients in Group A with DAT ≤ 12 months and 71 patients in Group B with DAT > 12 months. The two groups have similar clinical, electrocardiographic and echocardiographic characteristics. Intraprocedural pulmonary vein isolation was achieved in all patients. At the high-density left atrial BVM a concealed electrical remodelling was detected in group B in each LA segment (Fig.1), with the mean global LA voltage amplitude significantly lower in patients with DAT>12 months (group A 2.32±0.81 mV vs group B 1.47±0.74 mV, p<0.01). After a median follow-up of 11.9±9.4 months, 14 patients (11.4%) had AF recurrencies following the first ablation procedure. A significant lower rate of AF recurrence was found among patients with DAT < 12 months (Fig. 2): 2 patients in group A vs 12 patients in group B (4% vs 18.2%, p<0.01). Conclusion Patients with paroxysmal atrial fibrillation with DAT>12 months have significantly lower bipolar LA voltages, revealing a concealed atrial remodelling. Furthermore, DAT>12 months is associated with poor AF ablation outcome.

Evaluation of laser balloon pulmonary vein isolation lesions during the acute and chronic phases using a high-resolution mapping system

Abstract Funding Acknowledgements Type of funding sources: None. Background Visually guided laser balloon (VGLB) has proven ample efficacy in achieving durable pulmonary vein (PV) isolation (PVI). Though the isolation area post-cryoballoon ablation has been reported to regress at the chronic phase, the shrinkage of the isolation area using VGLB during the chronic phase has not been described. Purpose This study aims to evaluate the differences in isolation areas created by VGLB between the acute and chronic phases using a high-resolution mapping system. Methods We assessed 26 patients who underwent a second procedure due to atrial fibrillation recurrence. Of them, 8 patients were treated with the third-generation VGLB and 18 patients were treated with the first-generation VGLB at the first session. In all patients, the voltage maps were created with high-resolution mapping catheters just after PVI (acute phase) and during the second session (chronic phase). With each map, the isolation area (<0.1mV) around the PV antrum was calculated. We validated the persistent durability of PVI, and then the regression of isolation lesions was analyzed in patients without any PV reconnections. Results The isolation areas were re-evaluated at 8.3±6.6 months after the initial procedure. Twenty patients (76.9%) preserved persistent isolation lesions of all four PVs. Of them, the reduction of the isolation areas on the left- and right-sided PV antrum were 1.6±3.2 cm² (10.7±23.1% of the acute phase) and 4.8±3.6 cm² (27.8±18.9%), respectively. The analysis of the results revealed that the isolation area of the right-sided PV antrum yielded statistical shrinkage during the chronic phase (P=0.001), even though the electrical isolation was preserved. Conclusion After VGLB ablation, the isolation area of the right-sided PV antrum significantly regressed at the chronic phase, while the rate of durable PVI was high in line with the previous report.

Is pulmonary vein isolation using pulse field ablation safe and efficient ? data from a prospective registry

Abstract Funding Acknowledgements Type of funding sources: None. Background Pulsed field ablation (PFA) is a nonthermal ablative modality using a strong electrical field created around a dedicated catheter to produce pores in the cellular membrane. As the amount of energy required to produce electroporation is highly tissue dependent, the atrial myocardium can be specifically targeted while sparing adjacent tissues. This new ablation modality could increase the safety of pulmonary vein isolation (PVI) procedures compared to PVI using thermal energies. Real-life clinical data are still limited regarding safety and efficacy of PFA. Purpose To assess safety and mid-term efficacy of PVI performed using PFA. Methods We included all patients who underwent PVI for symptomatic atrial fibrillation (AF) using PFA in our hospital between June 2021 and June 2022. All procedures were performed under general anaesthesia. After patients received IV heparin and achieved ACT > 300 s, a 12 Fr multi-electrode pentaspline PFA catheter was advanced through a 13 Fr deflectable sheath into the left atrium. The catheter was positioned so that the splines achieved circumferential contact at the PV antra. Two applications (2.5 sec and 2 kV per application) were performed in "basket" configuration, then the catheter was slightly rotated (30-40°) before delivery of 2 additional applications. This sequence of ablation was repeated in "flower" configuration. This protocol was applied at each pulmonary vein. PVI was assessed with the PFA catheter. A 24-hour holter monitoring was performed at 4-month and one-year follow-up. Results The population consisted of 102 patients (73 paroxysmal AF, 29 persistent AF) with a mean age of 56 ± 13 yo. The mean procedure duration was 38 ± 9 min, and mean fluoroscopy duration was 8 ± 4 min (4 ± 4.2 Gy.cm2). The pulmonary vein signal completely disappeared after the first PFA application for each targeted vein and PVI was confirmed for all veins in all patients at the end of the procedure. Pericardial effusion requiring percutaneous drainage occurred in 1 patient during the early phase of our experience (patient n°8). There was no other complication. At 4-month follow-up, 91/102 patients (89%) were asymptomatic with no recurrence of AF. At one-year follow-up, 34/38 patients (89%) had no reccurence of documented atrial arrhythmia. 6 patients underwent a redo procedure : pulmonary vein reconnection was observed in 4/6. Conclusion PVI performed with PFA appeared safe and efficient with short procedure and acceptable fluoroscopy durations. Further data are required regarding long-term efficacy.

Left common trunkus pulmonary veins have genetic background and poor rhythm outcome after atrial fibrillation catheter ablation

Abstract Funding Acknowledgements Type of funding sources: None. Background There is a genetic background in pulmonary vein (PV) development and atrial fibrillation (AF). However, the genetic trait of PV variations and their rhythm outcome after AF catheter ablation (AFCA) is unclear. Objective We explored the genetic and clinical characteristics and long-term rhythm outcomes of AF patients with PV variation or left common trunkus (LCT)-PV. Methods We included 2,897 AF patients (74.0% male, age 59.0 ± 10.7 years, 66.3% paroxysmal AF) with available genome-wide association study results, cardiac computed tomogram data, and protocol-based regular rhythm follow-up from the Yonsei AF ablation cohort database. We defined LCT-PV when the upper and lower PV separate at >10 mm distal to the left PV antrum margin. PV variations included both LCT-PV and accessory PVs. We analyzed the polygenic risk score (PRS) of 12 AF-associated genes (DSP, GJA1, HCN4, KCNQ1, NPPA, PITX2, RYR2, SCN5a, SHOX2, ATP2A2, TBX3, and TBX5) and long-term rhythm outcomes after AFCA. Results We found PV variation in 296 (10.2%) and LCT-PV in 102 (3.5%). PRS of 1,227 single nucleotid polymorphisms (SNPs) was significantly higher in PV variation patients (p=4.93e-08) and LCT-PV patients (p=1.95e-20). The patients with LCT-PV had higher CHA2DS2VASc scores (p=0.024) and lower atrial epicardial adipose tissue volume (p=0.034). During 39.7 ± 34.8 months follow-up period, LCT-PV patients had a significantly higher recurrence rate than their counter part in the paroxysmal AF sub-group (Log-rank p=0.036), but not in overall PV variations. LCT-PV with the highest 10% PRS was independently associated with AF recurrence after AFCA (HR 2.10, 95% CI 1.21-3.63, p=0.008). Conclusions Among the patients who underwent AFCA, PV variation, including LCT-PV, has a significant genetic background. The post-AFCA recurrence rate was significantly higher in patients with LCT-PV and high PRS, especially in paroxysmal AF.

Insights into level of pulmonary vein isolation using pulsed-field ablation for atrial fibrillation and unexpected effects in the posterior wall

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction Pulse field ablation (PFA) has emerged as an effective, safe and efficient tool for pulmonary vein isolation (PVI). Purpose We studied the extent of PVI, specifically the isolation of PV antrum, carina and left atria’s posterior wall after PFA with an ultrahigh density mapping (UHD). Methods We involved the first patients referred for atrial fibrillation (AF) ablation treated with a PFA multispline catheter. PFA-lesion extension was assessed with a voltage-map UHD mapping performed before and immediately after PVI. Results Sixty-one consecutive patients underwent PVI with PFA (62±10 year old, 23 women, 39 paroxysmal AF). Four out of 61 patients were excluded because their posterior wall was isolated with extra aplications on purpose. Acute results involved a 100% success of PVI and the only safety issue was a pericardial effusion in one patient managed conservatively. Mean procedure and fluoroscopy times were 59±39 min and 16±5 min, respectively. UHD immediately after PVI revealed early reconnection just in one vein (1/228 veins). PFA created wide antral circumferential lesions without electrical activity registered by UHD mapping inside the isolation area. There were no notch-like normal voltage areas at the anterior or posterior side of carinas. As a result of the PVI with this technology, it was observed the existence of a narrow corridor in the posterior wall in 8 patients (14%) and in another 8 cases right and left antral ablation converged at the posterior wall creating an unexpected isolation area. There was a significant relationship between LA posterior inter-carina distance and posterior wall´s level of isolation (77,1±7mm, no affectation; 68,8±7mm narrow corridor; 60,3±1mm posterior wall isolation (fig 1); p=0.036). Finally, it was a significant linear correlation between posterior inter-carina distance and the distance between the ipsilateral, antral levels of isolation at the posterior wall (fig 2, r=0.79, p=0.001) Conclusion(s) PFA creates wide antral circumferential PVI lesions involving the ipsilateral veins carina. Nevertheless, in small left atria it can create an undesired isolation or a narrow corridor in the posterior wall.

Cerebral microembolic signal burden during pulsed field ablation: preliminary results from robotically-assisted transcranial doppler and magnetic resonance imaging

Abstract Funding Acknowledgements Type of funding sources: None. Background Transcranial Doppler (TCD) has been used to monitor the burden of cerebral microembolic signals (MESs) during atrial fibrillation (AF) ablation. MES burden is considered a surrogate marker for stroke risk and has never been reported during AF ablation with pulsed field ablation (PFA). Purpose To assess the MES burden during AF ablation with point-by-point radiofrequency (RF) versus single-shot PFA. Methods Fifteen consecutive paroxysmal and persistent AF patients underwent catheter ablation via either single-shot (2000V) PFA [n=7, median age: 56yo (range:53-73), 85.7% males] or point-by point (45W) RF [n=8, median age: 58yo (range 56-74), 62.6% males] under uninterrupted oral anticoagulation and a periprocedural ACT≥300s. Peri-procedural TCD was performed via a robotically-assisted ultrasound system, which includes an Artificial Intelligence-powered robotic headset designed to automate signal acquisition and reduce interoperator variability of TCD findings (Figure 1). Ablation-related asymptomatic cerebral embolism (CE) was assessed via diffusion-weighted imaging (DWI) sequences at magnetic resonance imaging (MRI) performed 24-48h post-ablation. Results Among the 7 PFA patients, the median number of applications to achieve PV isolation was 35 (range:33-42). Five (71.4%) patients showed multiple MESs clustered in a shower-like pattern (Figure 2). The overall number of MES-showers was 51 [median: 9 (range:8-15)] and they were temporally correlated with a PFA application. Shower formation was more common after a PFA application to the right superior pulmonary vein [(PV); 19 cases (37.3%)], followed by the right inferior PV [16 cases (31.4%)], the left inferior PV [14 cases (27.5%)], and the left superior PV [2 cases (3.9%)]. A single shower-like pattern was documented among the 8 RF patients, following a stem-pop while ablating at the right inferior PV antrum. There were no procedure-related complications and none of the 15 patients showed any post-ablation neurological symptoms. The mean time from ablation to MRI was 29±4hours; DWI imaging revealed no acute cerebral microembolic lesions. Conclusion PFA generated a relevant number of MESs frequently clustered in short-lasting shower-like patterns. The composition of MESs, their exact mechanism of formation, and the impact on neurological outcomes are unknown and will be addressed in future studies.

P104 LASER BALLOON APPROACH FOR PULMONARY VEIN ISOLATION IN MARFAN SYNDROME

Abstract Background Marfan syndrome (MFS) is an autosomal dominant disorder of the connective tissue and it’s associated with an increased incidence of atrial fibrillation (AF), due to scar–mediated processes and sites of atrial ectopy. Limited data exist regarding ablation techniques in these patients. The frailty of atrial walls correlated to connective disease makes the ablation challenging with an increased risk of complications. Laser–balloon (LB) approach for pulmonary vein isolation (PVI) could be a promising strategy due to the possibility to ablate a large volume of tissue with a single application of energy, short procedure times, and real–time monitoring of balloon–tissue contact. We present a case in which LB technology was applied for PVI in an MFS patient Clinical case A 44–year–old woman with MFS and paroxysmal AF underwent PVI. The echocardiographic examination showed mild aortic and mitral valve regurgitation, the first due to a slight dilation of the aortic root, the latter associated with mitral valve prolapse. Atrial volume was normal. No other comorbidities were present. The procedure was executed in general anesthesia. A decapolar catheter was inserted in the coronary sinus and used later to stimulate the phrenic nerve during the ablation of the right pulmonary veins (Fig.1C). Left atria (LA) was reached after an ultrasound–guided transeptal puncture. High–density mapping of the LA was performed to assess the number and geometry of PVs (Fig.1A). A LB catheter was used to perform laser ablation at the level of PV antrum, delivering 13 W in automatic rapid mode in regions with optimal contact and 5.5 W in areas with more represented blood–tissue interface. LA mapping after ablation assessed the effective isolation of pulmonary veins (Fig.1B). No complications occurred during the procedure. Conclusion a laser–balloon approach for PVI in MFS patients seems feasible and safe. To our knowledge, this is the first application of this technology on MFS patients. Larger data are needed to confirm our findings.

Personalized pulmonary vein antrum isolation guided by left atrial wall thickness for persistent atrial fibrillation.

Pulmonary vein (PV) antrum isolation proved to be effective for treating persistent atrial fibrillation (PeAF). We sought to investigate the results of a personalized approach aimed at adapting the ablation index (AI) to the local left atrial wall thickness (LAWT) in a cohort of consecutive patients with PeAF. Consecutive patients referred for PeAF first ablation were prospectively enrolled. The LAWT three-dimensional maps were obtained from pre-procedure multidetector computed tomography and integrated into the navigation system. Ablation index was titrated according to the local LAWT, and the ablation line was personalized to avoid the thickest regions while encircling the PV antrum. A total of 121 patients (69.4% male, age 64.5 ± 9.5 years) were included. Procedure time was 57 min (IQR 50-67), fluoroscopy time was 43 s (IQR 20-71), and radiofrequency (RF) time was 16.5 min (IQR 14.3-18.4). The median AI tailored to the local LAWT was 387 (IQR 360-410) for the anterior wall and 335 (IQR 300-375) for the posterior wall. First-pass PV antrum isolation was obtained in 103 (85%) of the right PVs and 103 (85%) of the left PVs. Median LAWT values were higher for PVs without first-pass isolation as compared to the whole cohort (P = 0.02 for left PVs and P = 0.03 for right PVs). Recurrence-free survival was 79% at 12 month follow-up. In this prospective study, LAWT-guided PV antrum isolation for PeAF was effective and efficient, requiring low procedure, fluoroscopy, and RF time. A randomized trial comparing the LAWT-guided ablation with the standard of practice is in progress (ClinicalTrials.gov, NCT05396534).

PO-01-068 CRYOBALLOON ABLATION FOR ATRIAL FIBRILLATION WITH LEAD-FREE ZERO FLUOROSCOPY APPROACH INTEGRATING PULMONARY VEIN HEMODYNAMICS, INTRACARDIAC IMAGING, AND 3D MAPPING: A FOUR-YEAR SINGLE-CENTER EXPERIENCE

Electrophysiologists have for years been plagued with the dangers of prolonged radiation exposure and associated long-term use of lead aprons. Patients also are exposed to significant amounts of radiation during fluoroscopy-guided catheter ablations. As such, efforts are being made to pioneer techniques which do not require fluoroscopy without sacrificing efficacy, safety, and patient outcomes. To evaluate the acute safety and efficacy of zero fluoroscopy cryoballoon ablation (ZFC) for atrial fibrillation (AF) with guidance from intracardiac echocardiography (ICE), pulmonary vein (PV) hemodynamics, and 3-dimensional (3D) mapping. Contiguous patients in a single center underwent ZFC for AF with ICE guidance, PV occlusion monitoring using hemodynamics, and 3D mapping. The superior vena cava was visualized with ICE, transseptal puncture was performed and LA sheath placement was confirmed with ICE. ICE catheter was then advanced into the LA through the same transseptal puncture. 3D mapping of the LA was performed, cryoballoon was advanced into the PV antrum, and seal was confirmed with ICE, color-flow dopper, and PV pressure waveform monitoring. Wide antral circumferential ablation was performed along all PVs. During ablation of right PVs, the phrenic nerve was monitored using palpation, liver capsule excursion noted on ICE, and pulsed wave doppler of the liver capsule. 3D mapping was used to ascertain entrance and exit blocks and circumferential antral isolation. A retrospective analysis of patients undergoing ZFC for treatment of AF from November 2018 to September 2022 was completed. The sample included 433 patients (219 women [50.6%] with a mean age of 66.5±11.6 years). Mean total procedure time was 49.3±12.0 minutes, mean LA dwell time was 36.5±10.3 minutes, and mean duration of cryoballoon application was 15.9±4.0 minutes. Procedural complication rates were 0.6% for effusions, 1.3% for phrenic nerve dysfunction, 0.8% for phrenic nerve palsy, 0.1% for vascular complications, 0% for esophageal injury, and 0.5% for all-cause mortality. Our single center experience demonstrates the feasibility of safely and effectively completing cryoballoon ablations for atrial fibrillation with a lead-free zero fluoroscopy approach. Additional multi-center studies are needed to ascertain the wide-scale applicability of this approach. The center acknowledges the learning curve associated with this skill set.

AB-453068-2 IS PULMONARY VEIN ISOLATION USING PULSE FIELD ABLATION SAFE AND EFFICIENT ? DATA FROM A PROSPECTIVE REGISTRY

Pulsed field ablation (PFA) is a nonthermal ablative modality using a strong electrical field created around a dedicated catheter to produce pores in the cellular membrane. As the amount of energy required to produce electroporation is highly tissue dependent, the atrial myocardium can be specifically targeted while sparing adjacent tissues. This new ablation modality could increase the safety of pulmonary vein isolation (PVI) procedures compared to PVI using thermal energies. Real-life clinical data are still limited regarding safety and efficacy of PFA. To assess safety and mid-term efficacy of PVI performed using PFA. We included all patients who underwent PVI for symptomatic atrial fibrillation (AF) using PFA in our hospital between June 2021 and June 2022. All procedures were performed under general anaesthesia. After patients received IV heparin and achieved ACT > 300 s, a 12 Fr multi-electrode pentaspline PFA catheter was advanced through a 13 Fr deflectable sheath into the left atrium. The catheter was positioned so that the splines achieved circumferential contact at the PV antra. Two applications (2.5 sec and 2 kV per application) were performed in "basket" configuration, then the catheter was slightly rotated (30-40°) before delivery of 2 additional applications. This sequence of ablation was repeated in "flower" configuration. This protocol was applied at each pulmonary vein. PVI was assessed with the PFA catheter. A 24-hour holter monitoring was performed at 4-month and one-year follow-up. The population consisted of 102 patients (73 paroxysmal AF, 29 persistent AF) with a mean age of 56 ± 13 yo. The mean procedure duration was 38 ± 9 min, and mean fluoroscopy duration was 8±4 min (4±4.2 Gy.cm2). The pulmonary vein signal completely disappeared after the first PFA application for each targeted vein and PVI was confirmed for all veins in all patients at the end of the procedure. Pericardial effusion requiring percutaneous drainage occurred in 1 patient during the early phase of our experience (patient n°8). There was no other complication. At 4-month follow-up, 91/102 patients (89%) were asymptomatic with no recurrence of AF. At one-year follow-up, 34/38 patients (89%) had no reccurence of documented atrial arrhythmia. 6 patients underwent a redo procedure : pulmonary vein reconnection was observed in 4/6. PVI performed with PFA appeared safe and efficient with short procedure and acceptable fluoroscopy durations.

MP-453081-9 CARDIAC SYMPATHOEXCITATION MONITORING DURING PULMONARY VEIN ISOLATION BY PSYCHOGENIC SWEATING: POSSIBILITY OF REPRESENTING CARDIAC SYMPATHETIC NEUROMODULATION

Vagal responses during pulmonary vein isolation (PVI) have been reported, suggesting cardiac neuromodulation in atrial fibrillation (AF) patients. The cardiac sympathetic nervous system also innervates the left atrium (LA) and its nerve fibers are reported to be greatly distributed around the PV antrum. However, the sympathetic nervous system’s response during PVI is unclear and the precise method to evaluate the cardiac sympathetic reflex is still not established. Psychogenic sweating (skin potential response; SPR) occurs during sympathetic excitation and may be useful to represent cardiac sympathoexcitation during PVI. We investigated whether the SPR could represent a cardiac sympathetic response during a balloon-based PVI and considered its clinical implications in persistent AF patients. Eighty persistent AF patients (Hot-balloon;45pt, Cryoballoon;35pt) were enrolled and the SPR was monitored during balloon-based ablation of each PV. The SPR was measured by the difference in two skin potentials recorded from skin electrodes (Figure top row). The reduction in the activation recovery interval (ARI), suggesting sympathetic excitation, was examined from the ventricle unipolar electrogram of the great cardiac vein recorded from an electrode catheter placed inside the coronal sinus (Figure bottom row). An ROC analysis was used to determine a valid reduction in the SPR, with a reduction cut-off value of 3.5mV in the heart rate (HR) increase due to sympathoexcitation (sensitivity 73%, specificity 97%). SPRs occurred in 41% of the PVs (LSPV=41%, RSPV=38%, LIPV=28%, RIPV=20%). The SPR was related to a significant increase in the blood pressure and HR, and a reduction in the ARI (p<0.01, Table). A total of 18 patients (20%) had AF recurrences within the 1-year follow-up. The number of SPRs within the 4PVs was 1.08PV in non-recurrence patients and 1.83PV in AF recurrent patients (p=0.07). The patients that had early recurrences but recovered sinus rhythm (SR) within 3 months, had more frequent SPRs than the other recurrent patients (2.80 vs. 0.63PV, p<0.01). The SPR was strongly related to cardiac sympathoexcitation during PVI. The SPR was suggested to represent the cardiac sympathetic reflex during PV antrum ablation, which may lead to an investigation of the cardiac sympathetic neuromodulation during PVI. Frequent SPRs were related to SR recovery after early AF recurrences and a cardiac sympathetic response may have an important role in the outcome of the PVI.

Differences in Post Ablation Cardiac MRI Scar Between Radiofrequency and Cryoballoon Ablation: A DECAAF II Sub-analysis.

Pulmonary vein isolation (PVI) using radiofrequency (RF) and cryoballoon (Cryo) ablation are standard approaches for rhythm control in patients with symptomatic atrial fibrillation. Both strategies create scar in the left atrium (LA). There have been few studies investigating the difference in scar formation between patients undergoing RF and Cryo using cardiac magnetic resonance imaging (CMR). The current study is a sub-analysis of the control arm of the Delayed-Enhancement MRI Determinant of Successful Catheter Ablation of Atrial Fibrillation study (DECAAF II). The study was a multicenter, randomized, controlled, single blinded trial that evaluated atrial arrhythmia recurrence (AAR) between PVI alone and PVI plus CMR atrial fibrosis guided ablation. Pre-ablation CMR and 3-6-month post ablation CMR were obtained to assess baseline LA fibrosis and scar formation respectively. Of the 843 patients randomized in the DECAAF II trial, we analyzed the 408 patients in the primary analysis control arm that received standard PVI. Five patients received combined RF and Cryo ablations so were excluded from this sub-analysis. Of the 403 patients analyzed, 345 underwent RF and 58 Cryo. The average procedure duration was 146 minutes for RF and 103 minutes for Cryo (p = 0.001). The rate of AAR at ~15 months occurred in 151 (43.8%) patients in the RF group and 28 (48.3%) patients in the Cryo group (p = 0.62). On 3-month post CMR the RF arm had significantly more scar (8.8% vs. 6.4%, p = 0.001) compared to Cryo. Patients with ≥ 6.5% LA scar (p < 0.001) and ≥ 2.3% LA scar around the PV antra (p = 0.01) on 3-month post CMR had less AAR independent of ablation technique. Cryo caused a greater percentage of right and left pulmonary vein (PV) antral scar (p = 0.04, p = 0.02) and less non-PV antral scar (p = 0.009) compared to RF. On Cox regression Cryo patients free of AAR had a greater percentage of left PV antral scar (p = 0.01) and less non-PV antral scar (p = 0.004) compared to RF free of AAR. In this sub-analysis of the control arm of the DECAAF II trial, we observed that Cryo formed a greater percentage of PV antral scar and less non-PV antral scar compared to RF. Post ablation LA scar ≥ 6.5% predicted freedom from AAR, independent of ablation technique. These findings may have prognostic implications in ablation technique selection and freedom from AAR. This article is protected by copyright. All rights reserved.

Coupled thermal-hemodynamics computational modeling of cryoballoon ablation for pulmonary vein isolation

Cryoballoon ablation (CBA) is a cryo-energy based minimally invasive treatment procedure for patients suffering from left atrial (LA) fibrillation. Although this technique has proved to be effective, it is prone to reoccurrences and some serious thermal complications. Also, the factors affecting thermal distribution at the pulmonary vein-antrum junction that are critical to the treatment success is poorly understood. Computer modeling of CBA can resolve this issue and help understand the factors affecting this treatment. To do so, however, numerical challenges associated with the simulation of advection-dominant transport process must be resolved. Here, we describe the development of a thermal-hemodynamics computational framework to simulate incomplete occlusion in a patient-specific LA geometry during CBA. The modeling framework uses the finite element method to predict hemodynamics, thermal distribution, and lesion formation during CBA. An incremental pressure correction scheme is used to decouple velocity and pressure in the Navier-Stokes equation, whereas several stabilization techniques are also applied to overcome numerical instabilities. The framework was implemented using an open-source FE library (FEniCS). We show that model predictions of the hemodynamics in a realistic human LA geometry match well with measurements. The effects of cryoballoon position, pulmonary vein blood velocity and mitral regurgitation on lesion formation during CBA was investigated. For a −700C cryoballoon temperature, the model predicts lesion formation for gaps less than 2.5 mm and increasing efficiency of CBA for higher balloon tissue contact areas. The simulations also predict that lesion formation is not sensitive to variation in pulmonary vein blood velocity and mitral regurgitation. The framework can be applied to optimize CBA in patients for future clinical studies.

The Minimum Number of Ablation Lines for Complete Isolation of the Pulmonary Veins during Thoracoscopic Ablation for Atrial Fibrillation.

Total thoracoscopic ablation has been recommended as a class IIa indication for atrial fibrillation. However, the optimal number of ablation lines for pulmonary vein isolation has not yet been proposed. This study aimed to report the minimum number of ablation lines required to achieve an intraoperative conduction block. This study included a total of 20 patients who underwent total thoracoscopic ablation from December 2020 to July 2021. The epicardial conduction block was checked after each ablation line of pulmonary vein antral clamping. The median age was 61 years old. The median duration of atrial fibrillation since the first diagnosis was 78 months. Pulmonary vein isolation with bidirectional conduction block was confirmed in 90% of patients. A median of six ablation lines around each pulmonary vein antrum were performed according to our protocol even after the conduction block was verified. The median number of ablations to achieve an exit block was two on the right side and 3.5 on the left side. We found that most conduction blocks were achieved within three ablations around the pulmonary vein antrum. Our results may provide evidence to reduce the number of unnecessary ablation lines in the future.

Clinical Electrophysiological Features and Radiofrequency Ablation of Patients with Atrial Fibrillation.

This study aimed to investigate electrophysiological features of radiofrequency ablation surgery in patients with the atrial fibrillation (AF). Fifty patients were included in this study and evenly divided, with 25 AF patients in the experiment group and 25 patients with arrhythmias in the control group. General clinical materials in the two groups were collected. Then, patient number of pulmonary vein antrum potential trial, intra-right atrial conduction time, intra-left atrial conduction time, interatrial conduction time, conduction time between atrium, and pulmonary veins trials were utilized to measure the efficacy of radiofrequency ablation surgery in patients with AF and clarify the relationship between AF and electrophysiological features in the atrium and pulmonary veins. Our study findings showed that conduction time interval between the atrium and pulmonary veins trial by radiofrequency ablation surgery were significantly less than those in pre-treatment AF patients. We can conclude that radiofrequency ablation surgery can effectively treat AF patients by relieving the electrophysiological dysfunction, and radiofrequency ablation can be used to prevent the development of AF.