Electrical Isolation Of Pulmonary Veins Research Articles

Charge-density mapping to evaluate non-pulmonary vein substrate in patients with paroxysmal atrial fibrillation: the ACUPRED study

Abstract Background/introduction Pulmonary veins (PV) electrical isolation (PVI) is the main ablation strategy for the treatment of paroxysmal atrial fibrillation (AF), since the description of PV triggers. However, non-PV substrate and triggers in AF are not a negligible clinical issue. Indeed, in up to 22% of patients with AF recurrence after PVI, all PV are found isolated. Non-PV triggers can be demonstrated in up to 10-15% of non-selected patients at first AF ablation and non-PV substrate has been related to functional slow conduction and fibrosis also in paroxysmal AF. Purpose The aim of this study is to evaluate non-PV substrate (slow conduction) and triggers with charge-density (CD) mapping in patients with paroxysmal AF. Methods All patients, were prospectively enrolled in 2023. Inclusion criteria for the study were: 1) paroxysmal AF patients undergoing PVI procedure with a single-shot device and 2) CD mapping pre- and post- PVI. CD mapping was performed during CS proximal pacing at cycle length (CL) 600 ms and CS proximal pacing at CL 300 ms, pre- and post- PVI. Conduction velocity (CV) magnitude (in cm/s) and vector (direction and sense) were calculated offline for each CD map for all anatomical vertices. Reduction map was defined as the map of CV magnitude difference between CL 600 ms and CL 300 ms, Figure 1. Refraction map was defined as the map of CV direction difference between CL 600 ms and CL 300 ms, Figure 1. Non-PV substrate was defined at pre-PVI maps as: 1) slow conduction (<30 cm/s) at CL 600 ms or CL 300 ms, or 2) difference in CV magnitude (>25 cm/s) at reduction map, a marker of functional slow conduction (induced by fast pacing), or 3) difference in CV direction more than 90° between two neighboring vertices at refraction map, a marker of anisotropy, Figure 1. Non-PV triggers were defined as non-PV premature atrial contractions >10/min or inducing AF. Results A total of 43 patients (60.6 ± 11.2 years, 74.4% males) with paroxysmal AF undergoing first procedure PVI were analyzed. Non-PV substrate was found in 13 patients (30.2%). Non-PV triggers were found in 3 patients (6.9%), including one patient on the posterior wall near right PV antra and two patients on the posterior wall near the left PV antra. At a mean follow-up of 5.6 months, a total of 5 patients (11.6%) experienced a recurrence. Patients experiencing a recurrence had more frequently non-PV substrate (80.0% vs 23.7%, p=0.024) and lower CV magnitude at CL 600 ms pre-PVI (72.3 cm/s vs 83.1 cm/s, p=0.04). At survival analysis for 34 patients (79.1%) out of the 2 months blanking period, patients with non-PV substrate had lower freedom from AF recurrence (56% vs 90%, p=0.0028), Figure 2. Conclusion In patients with paroxysmal AF undergoing index PVI, non-PV substrate or triggers can be found in up to 37.1% of cases. Non-PV substrate is associated with worse arrhythmic prognosis.Figure 1Figure 2

Impact of pulmonary vein variant anatomy during cryo-ablation in paroxysmal and persistent AF patients: 1-year outcome from a nationwide multicenter clinical setting

Abstract Background Complete electrical pulmonary vein isolation (PVI) by cryo-balloon approach is a well-established ablation strategy of atrial fibrillation (AF). While contrast findings exist regarding the influence of variant pulmonary vein (PV) anatomy on predicting AF recurrence, limited data are currently available specifically for cases involving the POLARx cryoablation system during PVI. Purpose We report the real-world experience of POLARx in the context of de novo AF ablation in a multicenter Italian registry. Methods Consecutive patients undergoing AF ablation from the CHARISMA registry at 10 Italian centres were included. Protocol-directed cryoablation was delivered for 180 sec or 240 sec according to operator’s preference for isolation achieved in ≤60 sec, or 240 sec if isolation occurred >60 sec or when time to isolation was not available. The ablation endpoint was PVI as assessed by entrance and exit block. All patients were followed-up for at least 12 months after the procedure. Results Four-hundred twenty-nine patients were included (n=358, 83.4% paroxysmal AF, n=71, 16.6% persistent AF, mean age 60.7±10 years, 28.3% female, mean LVEF 58±8%). PVI was achieved in all pts using only cryoablation. Twenty-eight (6.6%) patients exhibited an anatomical variant: 17 (4.0%) a common ostium and 11 (2.6%) an adjunctive PV. The mean number of freeze applications per patient was 5.1 (1.2 for LSPV, 1.3 for LIPV, 1.2 for RSPV and 1.3 for RIPV). Over a median of 398[370-461] days of follow-up, 14 (3.2%) patients experienced an early recurrence of AF during the 90-day blanking period. Overall, 63 patients (14.7%) suffered an AF recurrence after the 90-day blanking period (median time to recurrence 342[171-381] days). The proportion of patients exhibiting AF/AT recurrences was higher in the persistent AF group (17 out 71, 23.9%) than in the paroxysmal AF group (46 out 358, 12.8%, p=0.026), with a hazard ratio of 2.02 (95%CI: 1.2 to 3.5, p=0.0137) whereas patients with anatomy variant showed a similar AF/AT recurrence rate (5 out 28, 17.9%) than in the standard anatomy group (58 out of 401, 14.5%) with a hazard ratio of 1.43 (0.6 to 3.6, p=0.441). Four (0.9%) transient phrenic nerve palsy were observed, both with full recovery in the 48-h post procedure; no major procedure-related adverse events were reported. Conclusion In this multicenter study, the cryo-balloon system demonstrated safety and efficacy in treating both paroxysmal and persistent AF patients, yielding a low incidence of AF/AT recurrence during follow-up, regardless of the presence of variant PV anatomy.

Practicality and Safety of Electrical Pulmonary Vein Isolation and Left Atrial Appendage Ligation in Lung Transplant Recipients With Pretransplant Atrial Fibrillation.

Lung transplant surgery creates surgical pulmonary vein isolation (PVI) as a routine part of the procedure. However, many patients with pretransplant atrial fibrillation continue to have atrial fibrillation at 1 y. We hypothesized that the addition of electrical PVI and left atrial appendage isolation/ligation (LAL) to the lung transplant procedure restores sinus rhythm at 1 y in patients with pretransplant atrial fibrillation. We retrospectively reviewed all adult lung transplant recipients at the University of California Los Angeles from April 2006 to August 2021. All patients with pretransplant atrial fibrillation underwent concomitant PVI/LAL and were compared with lung transplant recipients without preoperative atrial fibrillation. In-hospital outcomes; 1-y survival; and the incidence of stroke, cardiac readmissions, repeat ablations, and sinus rhythm (composite endpoint) were examined at 1 y for the PVI/LAL cohort. Sixty-one lung transplant recipients with pretransplant atrial fibrillation underwent concomitant PVI/LAL. No patient in the PVI/LAL cohort required cardiac-related readmission or catheter ablation for atrial fibrillation within 1 y of transplantation. Freedom from the composite endpoint of death, stroke, cardiac readmission, and repeat ablation for atrial fibrillation at 1 y was 85% (95% confidence interval, 73%-92%) for lung transplant recipients treated with PVI/LAL. The addition of PVI/LAI to the lung transplant operation in patients with pretransplant atrial fibrillation was safe and effective in maintaining sinus rhythm and baseline risk of stroke at 1 y.

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

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

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

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

Application of Cut-and-Sew Technique in Thoracoscopic Minimally Invasive Mitral Valve Surgery and Concomitant Maze Procedure.

Atrial fibrillation is one of the common complications of mitral valve disease. Currently, in the absence of freezing equipment, it's still impossible to fully conduct a minimally invasive Cox-maze IV procedure to treat atrial fibrillation. We analyzed the clinical data of 28 patients who underwent thoracoscopic minimally invasive mitral valve full maze surgery in our hospital from October 2021 to September 2022; 13 patients were male and 15 were female, three suffered from paroxysmal atrial fibrillation, and 25 suffered from permanent atrial fibrillation; average age was 61.88±8.30 years, and mean preoperative left atrial diameter was 47.12±8.34 mm. Isolation of left atrial posterior wall (box lesion) was completed in all patients by cut-and-sew technique and bipolar clamp ablation. For these subjects, the median cardiopulmonary bypass time was 169 (109.75-202.75) minutes, aortic cross-clamping time was 106 (77.75-125.50) minutes, and ventilator assistance time was 6.5 (0-10) hours. Among them, eight subjects had the endotracheal tubes removed immediately after surgical operation. Three subjects were in the blanking period; two subjects still had atrial fibrillation at three months after operation, one of whom resumed sinus rhythm after electrical cardioversion therapy; and all the remaining 23 subjects had sinus rhythm. The minimally invasive cut-and-sew technique for electrical isolation of left pulmonary veins can improve sinus conversion rate of patients suffering from both mitral valve disease and atrial fibrillation. In selected subjects, it is safe and has good results in the short-term postoperative period.

The effect of high-power short-duration pulmonary vein isolation on PWPT-apredictor of paroxysmal atrial fibrillation.

The Pwave peak time (PWPT) is apredictor of paroxysmal atrial fibrillation (PAF). High-power short-duration ablation has been associated with improved durability of circumferential pulmonary vein electrical isolation (PVI). We investigated the effect of high-power short-duration PVI on PWPT in patients with PAF. Out of 111patients with PAF, 91received radiofrequency ablation (ablation group) and 20received medication treatment (control group). AVIZIGO sheath and anSTSF catheter (Biosense Webster, CA, USA) were used together for high-power short-duration circumferential PVI at ablation index values of 500 and 400 for the anterior and posterior walls, respectively. The patients were followed up for 12months. The preoperative PWPT in the ablation group was similar to that in the control group: PWPTII = 54.38 ± 6.18 ms vs. 54.35 ± 6.12 ms (p > 0.05), PWPT V1 = 54.19 ± 6.21 ms vs. 54.31 ± 6.08 ms (p > 0.05), respectively. Circumferential PVI was achieved for all patients in the ablation group during the operation. At the 12-month follow-up, there were seven cases of AF recurrence. The PWPT in the ablation group 12months postoperatively was shorter than the preoperative value: PWPTII = 49.39 ± 7.11 ms vs. 54.38 ± 6.18 ms (p < 0.001), PWPT V1 = 47.69 ± 7.01 ms vs. 54.19 ± 6.21 ms (p < 0.001). The PWPT in the patients with AF recurrence was significantly longer than that in the non-recurrence patients: PWPTII = 50.48 ± 7.12 ms vs. 47.33 ± 6.21 ms (p < 0.001), PWPT V1 = 50.84 ± 7.05 ms vs. 47.19 ± 6.27 ms, (p < 0.001). The PWPT of the control group at the 12-month follow-up was similar to the baseline level: PWPTII = 54.32 ± 6.20 ms vs. 54.35 ± 6.12 ms (p > 0.05), PWPT V1 = 53.89 ± 6.01 ms vs. 54.31 ± 6.08 ms (p > 0.05). The results showed that high-power short-duration PVI had apositive effect on PWPT, which is apredictor of PAF.

Novel pulsed-field ablation technology for pulmonary vein isolation in patients with atrial fibrillation: preliminary experience from a large multicenter clinical practice

Abstract Funding Acknowledgements Type of funding sources: None. Background Complete electrical pulmonary vein isolation (PVI) by thermal energy sources is a well-established ablation strategy of atrial fibrillation (AF). Recently, a non-thermal ablation approach by means of irreversible cellular electroporation has been made available for clinical use. Purpose We report the preliminary experience of a new pulsed-field ablation (PFA) system in the context of AF ablation in a multicenter Italian setting. Methods All consecutive patients (pts) undergoing AF ablation with PFA at 7 Italian centres were included. Protocol-directed PVI was delivered using 2000 V with eight applications per vein, that is, four applications each in the basket and flower poses. Applications were delivered in pairs at any given catheter position, rotating by ≈30–40° after the first two applications in each configuration. Additional lesions were performed at the operator’s discretion. The ablation endpoint was PVI as assessed by entrance and exit block. Data are reported as median [IQ range]. Results With a median of 32[25-38] pts treated per center, a total of 205 cases were included (n=150 73.2%, paroxysmal AF, n=55, 26.9% persistent AF). Of them 187 (91.2%) were de novo cases, whereas 18 (8.8%) were redo cases. A mapping system was used in 55 (21.5%) procedures and an intracardiac echocardiography in 65 (31.7%) cases. The number of PFA applications to reach PVI was 32[32-36]. Procedural parameters were: fluoroscopy time = 16[12-22] min, skin-to-skin time = 60[55-85] min, support time (preparation plus skin-to-skin) =75[64-95] min, lab occupancy time was 97[75-120] min and PFA LA dwell time was 23[20-28] min. The first pass isolation (FPI) rate per vein was 99.6% resulting from 202 patients (98.5%) with FPI. At the end of the procedure, PVI was achieved in all pts (100%) using only PFA. Additional PFA delivery outside PVs was performed in 19% (n=39) of the cases, mostly at the posterior wall area only (n=34, 87%), requiring 16[12-24] PFA deliveries. All the additional lesion sets were validated through differential pacing and/or 3D mapping. The learning curve was extremely fast. After only 5 cases time to PVI and total support time have significantly improved, whereas we did not notice any additional improvement after 10 or 20 cases (LA dwell time: 27[22-32] min during the first 5 cases vs 23[19-27] min after the first 5 cases, p=0.0172; support time: 100[65-120] min vs 75[65-90] min, p=0.0181, respectively). In 13 (6.3%) cases a transient bradycardia or asystole occurred after the first PFA application requiring temporary high-output pacing. No major procedure-related adverse events were reported. Conclusion In this first multicentric experience, the novel PFA system proved to be safe and effective in both paroxysmal and persistent AF patients. The learning curve seems to be very fast according with procedural parameters.

PO-02-001 MODIFIED BOX ABLATION WITH OR WITHOUT DRIVERS ABLATION FOR CHINESE PATIENTS WITH NON-PAROXYSMAL ATRIAL FIBRILLATION: A RETROSPECTIVE REAL-WORLD STUDY

The use of circumferential pulmonary vein electrical isolation (CPVI) combined with modified posterior wall box isolation (m-BOX) has been proved an improvement in the long-term success of chronic atrial fibrillation (AF) patients’ treatment. More evidence shows that electrical drivers are associated with the maintenance of persistent AF (PsAF). To explore the long-term effectiveness of m-BOX or m-BOX with driver-guided ablation for non-paroxysmal AF using high-density mapping (HOT). Data were obtained from electronic medical records between January 1,2018 and May 31, 2022 from Xiangya Hospital Central South University, Changsha, China. Patients aged ≥18 years, diagnosed as PsAF or long-standing PsAF and underwent either m-BOX or HOT index ablation after CPVI, were included. Patients were expected to follow up ≥12 months post index procedure. Recurrence was defined as AF, or atrial tachycardia, or flutter lasting ≥30 seconds after 3-month blanking period, which came first. The Cox proportional model adjusting for propensity score (including age, gender, AF type, baseline left ventricular ejection fraction, left atrial diameter, and medical history) was used for 2-group comparison. The proportion of patients with event, adjusted hazard ratio (HR) [95% CI], and stratified log-rank P were presented. A total of 148 and 113 patients were identified in the HOT and m-BOX groups, with mean (SD) ages 61.7 (10.1) and 60.8 (8.9) years, male sex 64.2% and 67.3%, and long-standing PsAF diagnosis in 54.1% and 41.6% of population, respectively. The 12-month recurrence rate was lower in the HOT group than in m-BOX group (21.8% vs. 34.8%, adjusted HR [95% CI]:0.49 [0.30,0.80]; P=0.005). In the HOT group, the recurrence rate of patients who restored sinus rhythm (SR) by ablation was numerically lower than those who did not (16.7% vs. 26.7%, adjusted HR [95% CI]:0.60 [0.28,1.28]; P=0.37). Regardless of the ablation strategy, the recurrence rate was lower when SR was restored by ablation (16.2% vs. 34.4%, adjusted HR [95% CI]:0.43 [0.24,0.76]; P=0.01). Restoration of SR in non-paroxysmal AF patients is associated with lower recurrence rates at 12 months. In patients who do not achieve SR after CPVI and m-BOX, HOT ablation may lead to improved long term clinical outcomes. Future’s prospective study is needed for a more comprehensive view of the comparison results.

Real-world trends in atrial fibrillation ablation indicate increasing durability of pulmonary vein isolation at repeat ablation.

Durable electrical isolation of pulmonary veins (PVs) is associated with better outcomes after atrial fibrillation (AF) ablation, but previous studies of AF recurrence have reported high rates of reconnection despite successful acute isolation. This study aims to quantify historical trends in the durability of PV isolation (PVI) as radiofrequency (RF) ablation catheters, additional ablation technologies, and associated workflows have evolved. The study population included adult patients receiving a first repeat ablation for AF between September 2013 and July 2019 at the study site. All index ablations were performed at the same site with an RF catheter and included PVI. Three generations of irrigated RF catheters based on the same technology platform were used by the site during the timeframe of this study. A total of 224 patients were included in the analysis. At repeat ablation, the mean number of patients with at least one reconnected PV dropped significantly with subsequent catheter generation, from 78.3% to 56.7% to 27.0% (p<.0001). Moreover, the mean number of reconnected PVs were significantly reduced from 1.48 to 0.92 to 0.47 (p<.0001), representing a 68.3% reduction across the 3 generations of devices. Significant improvement in durable PVI was seen with successive generations of RF catheter over a 6-year period. In addition to catheter technology, ancillary advances in ablation technologies, workflows, and operator experience likely contributed to these improvements.

An evaluation of the clinical efficacy of the application of 28mm cryoballoon for linear ablation of left atrial apex combined with enlarged pulmonary vein vestibule ablation for persistent atrial fibrillation

Objectiveto retrospectively investigate the efficacy and safety of the application of 28 mm cryoballoon for pulmonary vein electrical isolation (PVI) combined with top left atrial linear ablation and pulmonary vein vestibular expansion ablation for persistent atrial fibrillation. MethodsFrom July 2016 to December 2020, 413 patients diagnosed with persistent atrial fibrillation were evaluated, including 230 (55.7%) in the PVI group (PVI only) and 183 (44.3%) in the PVIPLUS group (PVI plus ablation of the left atrial apex and pulmonary vein vestibule). The safety and efficacy of the two groups were retrospectively analyzed. ResultsThe AF/AT/AFL-free survival rates at 6, 12, 18, 24 and 30 months after procedure was 86.6%, 72.6%, 70.0%, 61.1% and 56.3% in the PVI group and 94.5%, 87.0%, 84.1%, 75.0% and 67.9% in the PVIPLUS group, respectively. At 30 months after procedure, the AF/AT/AFL-free survival rate was significantly higher in the PVIPLUS group than in the PVI group (P = 0.036; HR:0.63; 95% CI:0.42 to 0.95). ConclusionThe application of 28-mm cryoballoon for pulmonary vein electrical isolation combined with linear ablation of the left atrial apex and expanded ablation of the pulmonary vein vestibule improves the outcome of persistent atrial fibrillation.

Cryoballoon-Induced Circumferential Pulmonary Vein Fibrosis, Assessed by Late Gadolinium-Enhancement Cardiac Magnetic Resonance Imaging, and Its Correlation with Clinical Atrial Fibrillation Recurrence.

Prior studies evaluating post-atrial fibrillation (AF) ablation pulmonary vein (PV) ostial gaps via magnetic resonance imaging (MRI) have shown circumferential PV fibrosis in a minority of patients, and their correlation with AF recurrence was weak. These studies were mostly based on radio-frequency AF ablations. We aimed to assess cryoballoon ablation-induced PV fibrosis via MRI and its correlation with AF recurrence. This was a prospective study of consecutive patients with symptomatic AF who underwent pre- and post-ablation MRI to assess baseline and ablation-induced fibrosis, respectively. Post-ablation PV gaps were assessed by new semi-quantitative visual analysis assisted by computerized ADAS analysis. AF recurrence monitored via multiple ECGs and event monitoring at 6 and 12 months post ablation. Nineteen patients with 80 PVs were included, age 56 ± 11, with paroxysmal and persistent AF in 17/19 and 2/19 patients, respectively. Baseline MRI showed minimal LA fibrosis. All patients underwent successful cryoballoon PV electrical isolation. Post-ablation MRI revealed circumferential PV fibrosis among 63/80 (78.8%) PVs and partial fibrosis with major gaps among 17/80 (21.2%) PVs. AF recurred within one year in 5/9 (55.5%) patients with partial PV fibrosis, while no AF recurred among the 10 patients in whom all PVs had circumferential fibrosis (p < 0.01). Similarly, there were significantly more PVs without circumferential fibrosis (due to major gaps) among patients with AF recurrence as compared with patients without AF recurrence (42.9% vs. 13.5%; p < 0.01). Cryoballoon AF ablation results in circumferential PV fibrosis in the majority of PVs, as assessed by a new clinically relevant MRI-LGE analysis. Significant correlation was found between major PV gaps on post-ablation MRI and AF recurrence, suggesting that MRI might have the ability to predict AF recurrence.

3D-electroanatomical mapping of the left atrium and catheter-based pulmonary vein isolation in pigs: A practical guide.

To propose a standardized workflow for 3D-electroanatomical mapping guided pulmonary vein isolation in pigs. Danish female landrace pigs were anaesthetized. Ultrasound-guided puncture of both femoral veins was performed and arterial access for blood pressure measurement established. Fluoroscopy- and intracardiac ultrasound-guided passage of the patent foramen ovale or transseptal puncture was performed. Then, 3D-electroanatomical mapping of the left atrium was conducted using a high-density mapping catheter. After mapping all pulmonary veins, an irrigated radiofrequency ablation catheter was used to perform ostial ablation to achieve electrical pulmonary vein isolation. Entrance- and exit-block were confirmed and re-assessed after a 20-min waiting period. Lastly, animals were sacrificed to perform left atrial anatomical gross examination. We present data from 11 consecutive pigs undergoing pulmonary vein isolation. Passage of the fossa ovalis or transseptal puncture was uneventful and successful in all animals. Within the inferior pulmonary trunk 2-4 individual veins as well as 1-2 additional left and right pulmonary veins could be cannulated. Electrical isolation by point-by-point ablation of all targeted veins was successful. However, pitfalls including phrenic nerve capture during ablation, ventricular arrhythmias during antral isolation close to the mitral valve annulus and difficulties in accessing right pulmonary veins were encountered. Fluoroscopy- and intracardiac ultrasound-guided transseptal puncture, high-density electroanatomical mapping of all pulmonary veins and complete electrical pulmonary vein isolation can be achieved reproducibly and safely in pigs when using current technologies and a step-by-step approach.

Multicenter prospective comparison of conventional and high-power short duration radiofrequency application for pulmonary vein isolation: the high-power short-duration radiofrequency application for faster and safer pulmonary vein ablation (POWER FAST III) trial.

Electrical isolation of pulmonary veins (PV) with high-power short-duration (HPSD) radiofrequency application (RFa) may reduce the duration of atrial fibrillation (AF) ablation, without compromising the procedural efficacy and safety in comparison with the conventional approach. This hypothesis has been generated in several observational studies; the POWER FAST III will test it in a randomized multicenter clinical trial. It is a multicenter randomized, open-label and non-inferiority clinical trial with two parallel groups. AF ablation using 70 W and 9-10s RFa is compared with the conventional technique using 25-40W RFa guided by numerical lesion indexes. The main efficacy objective is the incidence of atrial arrhythmia recurrences electrocardiographically documented during 1-year follow-up. The main safety objective is the incidence of endoscopically detected esophageal thermal lesions (EDEL). This trial includes a substudy of incidence of asymptomatic cerebral lesions detected by magnetic resonance imaging (MRI) after ablation. A randomized clinical trial compares for the first time high-power short-duration and conventional ablation in order to obtain data about the efficacy and safety of the high-power technique in an adequate methodological context. The results of the POWER FAST III could support the use of the high-power short-duration ablation in clinical practice. ClinicalTrials.gov: NTC04153747.

Ablation of atrial fibrillation beyond pulmonary vein isolation: Do additional ablation lesions impact left atrial function?

Electrical isolation of pulmonary veins (PVI) is a cornerstone for atrial fibrillation (AF) ablation. The overall effect of AF ablation, and especially lesions beyond PVI, on left atrial (LA) function is currently poorly understood. Our aim was to determine if LA function is different in patients after extensive LA ablation compared to PVI only. We performed non-inferiority analysis of LA function after PVI with additional nonpulmonary vein ablation lesions in LA (PVI+) and PVI alone. We studied 68 patients consecutive patients who underwent AF ablation and who had complete transthoracic echocardiogram (TTE) within 12 months before AF ablation and 1-12 months after the procedure. Patients were stratified into two groups: PVI only and PVI+. Primary outcome was change in LA reservoir strain (LASr). Noninferiority margin was defined at 6%. The PVI only group had a higher proportion of patients with paroxysmal AF (70% vs. 30%). The PVI+group was observed to have a slightly higher increase in LASr compared to PVI alone (5.0% vs. 4.3%, p < .01 for noninferiority). LASr noninferiority was confirmed when adjusted for age, sex, coronary artery disease, hyperlipidemia, andAF type, rhythm at preprocedure TTE in a multivariable linear regression model, 90% CI (-5.46 to 2.04), p < .01. LA functional improvement evaluated by LASr was noninferior after PVI with additional LA ablation lesions compared to PVI alone. These findings were confirmed when adjusted for confounding clinical variables, suggesting that more extensive ablation does not negatively affect LA function.

Abstract 15077: Reconnection of Pulmonary Veins and Left Atrial Posterior Wall Following Catheter Ablation for Atrial Fibrillation in Real-World Patients: Registry Data From a High-Volume Center

Introduction: Durable isolation of the pulmonary veins (PV) and the left atrial posterior wall (LAPW) are considered as key determinants of long-term success after catheter ablation in AF patients. Objective: We aimed to evaluate the PV and LAPW reconnection rate in real-world patients undergoing redo-ablation at our center. Methods: Consecutive AF patients that underwent their first AF ablation at our center from 2015-19 were included in this analysis. At the index procedure, all received electrical isolation of PVs and the LAPW area between the PVs, using radiofrequency (RF) ablation. Procedure was conducted with 3.5-mm irrigated-tip catheter guided by circular mapping catheter, intra-cardiac echocardiography and a 3-D mapping system. RF energy was delivered with a maximum temperature setting of 42 0 C, contact force of 10g and a power of up to 45W. Posterior wall isolation was performed using multiple ablation points covering the whole posterior wall. An esophageal probe was utilized in all patients to monitor esophageal temperature during ablation in the LAPW in close proximity to the esophagus. Complete abolition of all PV potentials rather than decrease in the amplitudes was the end point and confirmed by entrance and/or exit block. All patients were followed up prospectively for 2 years with quarterly evaluation during the first year and bi-annually afterwards and the data was collected in our IRB-approved AF registry. Recovery of conduction in the PVs and LAPW were assessed at the redo procedure using pacing or incremental isoproterenol infusion of 20- 30μg/min for 15-20min. Results: During the study period, 6,817 AF ablation procedures were performed at our institution of which 3,113 AF patients undergoing their first catheter ablation were included in the analysis and prospectively followed up for 2 years. Baseline characteristics of the study population is given in Table 1. At 23.1±12.8 months of follow-up, 614 (19.7%) patients had received redo-ablation, of which 139 (22.6%) had one or more PV or LAPW reconnected. Conclusion: In this series, with experienced operators performing the procedures, the rate of recovery of conduction in the PVs and LAPW was low compared to the reported high incidence rate in the literature.

Hybrid approach for long-standing persistent atrial fibrillation: immediate versus staged treatment

BackgroundThe hybrid approach has become the most effective treatment option for restoring sinus rhythm and reducing the risk of atrial fibrillation (AF) recurrence. However, several issues remain to be clearly defined, including the appropriate timing of the staged procedure and the most effective strategy.MethodsOver a 12-year period of activity, we performed 609 AF ablation procedures via a right mini-thoracotomy. From this general population, 60 patients underwent a hybrid procedure with catheter ablation performed at least 4 weeks after the surgical procedure to confirm if effective complete electrical isolation of pulmonary veins was achieved. In 20 patients, the second stage procedure was performed during the same hospitalization due to patient’s electrical instability. The results obtained in immediate versus staged patients were compared.ResultsAll patients were discharged after the first stage procedure in sinus rhythm. The 20 immediate patients had a shorter hospital stay compared with the staged patients, in whom the two hospitalizations resulted in a longer hospital stay (immediate 5.5 ± 1.6 days versus staged 8.7 ± 1.4, P < 0.001). A significantly higher number of immediate patients had an associated ablation of the Bachmann’s bundle (n = 16 in the immediate group [80%] versus n = 14 in the staged group [45%]; P = 0.001). After a mean follow-up of 74 months, there was no significant difference in the risk of AF relapse between groups (immediate 1/20 [5%] versus staged 7/40 [17.5%]; P = 0.18).ConclusionThe hybrid approach for the treatment of AF was safe and effective in immediate restoring sinus rhythm and in its maintenance at follow-up. Our preliminary results show that both immediate and staged procedures show similar efficacy but this result is strongly influenced by the concomitant ablation of the Bachmann’s bundle, which appears to be the most important component of the treatment strategy in order to reduce the risk of recurrent AF.

Advantage of POLARx over ARCTIC FRONT ADVANCE PRO during pulmonary vein isolation for paroxysmal atrial fibrillation

Abstract Introduction The electrical pulmonary vein (PV) isolation has been established as a curative therapy for paroxysmal atrial fibrillation (AF). Arctic Front™cryoballoon has been used worldwide for AF cryoablation. Recently, a new cryoballoon, POLARxTM CRYOABLATION system have been introduced, of which material of the balloon is softer and the N2O gas flow rate is higher. Purpose The aim was to investigate the procedural parameter and efficacy of POLARx comparing with Arctic Front. Methods This retrospective single center study included 101 consecutive patients who underwent paroxysmal AF ablation using cryoballoon at Keio University hospital from April 2021 to March 2022. The procedural data including the cryoballoon temperature and the number and duration of cryoablation were compared between POLARx (POLARx group) and ARCTIC FRONT ADVANCE PRO (AFA group). After the cryoablation, we added the radiofrequency application in order to maximize the isolated area when the voltage was remained inside PV (Figure 1). The necessities of the additional radiofrequency applications were also compared. Results In the present study, 64 patients in AFA group and 37 patients in POLARx group were analyzed. POLARx group included younger population and less females (62.8±9.9 vs 67.5±9.4 year of age, P=0.02; 13.5 vs 32.8%, P=0.04). There was no significant difference in comorbidities and examination data such as left atrium diameter or brain natriuretic peptide level. The minimal cryoballoon temperatures reached in POLARx group were lower than AFA group (−59.3±6.2 vs −47.7±7.5°C, P&amp;lt;0.01). No difference was found in the total number and duration of cryoablation and the time to isolate PV (6.1±2.1 vs 5.9±1.6, P=0.69; 790.2±256.1 vs 776.1±235.0 sec, P=0.69; 41.8±21.3 vs 47.1±29.6 sec, P=0.44, respectively). With regard to individual PVs, the total number and duration were tended to be larger at right superior PV in POLARx group (1.9±1.1 vs 1.4±0.7, P=0.01; 231.8±123.8 vs 193.2±83.0 sec, P=0.07), while there was no significant difference at the other PVs. The rate of successful PV isolation by a single cryo-application was not different between AFA and POLARx group (54.3 vs 61.4%, P=0.17). The additional radiofrequency applications were more frequent in AFA group (14.8 vs. 4.9%, P=0.003). There was a significant difference at right inferior PV (32.8 vs 8.1%, P=0.01), while not at left superior PV, left inferior PV and right superior PV (9.4 vs 2.9%, P=0.42; 9.4 vs 5.7%, P=0.71; 7.8 vs 2.7%, P=0.41). Phrenic nerve injury was occurred 1 case in both group and esophageal ulcer was occurred in 1 case in AFA group. No other complication including cardiac tamponade was occurred. Conclusion The total number and duration of cryoablation were not significantly different between AFA and POLARx group, except for right superior PV. There was an advantage in largely isolating right inferior PV in POLARx group comparing with AFA group. Funding Acknowledgement Type of funding sources: None.

Hybrid Ablation of Atrial Fibrillation: A Contemporary Overview.

Electrical isolation of pulmonary veins (PVI) is the cornerstone of invasive treatment of atrial fibrillation (AF). However, arrhythmia-free survival of a PVI only approach is suboptimal in patients with persistent and long-term persistent AF. Hybrid AF ablation has been developed with the aim of combining the advantages of a thoracoscopic surgical ablation (direct visualization of anatomical structures to be spared and the possibility to perform epicardial lesions) and endocardial ablation (possibility to check line block, confirm PVI, and possibility to perform cavotricuspid isthmus ablation). Patient selection is of utmost importance. In persistent and long-term persistent AF, hybrid AF ablation demonstrated promising results in terms of AF free survival. It has been associated with a relatively low complication rate if performed in centers with expertise in hybrid procedures and experience with both surgical and endocardial ablation. Different techniques have been described, with different approaches and lesion sets. The aim of this review is to provide a state-of-the-art overview of hybrid AF ablation.

Multielectrode Contact Measurement Can Improve Long-Term Outcome of Pulmonary Vein Isolation Using Circular Single-Pulse Electroporation Ablation.

Background:Irreversible electroporation (IRE) ablation is generally performed with multielectrode catheters. Electrode-tissue contact is an important predictor for the success of pulmonary vein (PV) isolation; however, contact force is difficult to measure with multielectrode ablation catheters. In a preclinical study, we assessed the feasibility of a multielectrode impedance system (MEIS) as a predictor of long-term success of PV isolation. In addition, we present the first-in-human clinical experience with MEIS.Methods:In 10 pigs, one PV was ablated based on impedance (MEIS group), and the other PV was solely based on local electrogram information (EP group). IRE ablations were performed at 200 J. After 3 months, recurrence of conduction was assessed. Subsequently, in 30 patients undergoing PV isolation with IRE, MEIS was evaluated and MEIS contact values were compared to local electrograms.Results:In the porcine study, 43 IRE applications were delivered in 19 PVs. Acutely, no reconnections were observed in either group. After 3 months, 0 versus 3 (P=0.21) PVs showed conduction recurrence in the MEIS and EP groups, respectively. Results from the clinical study showed a significant linear relation was found between mean MEIS value and bipolar dV/dt (r2=0.49, P<0.001), with a slope of 20.6 mV/s per Ohm.Conclusions:Data from the animal study suggest that MEIS values predict effective IRE applications. For the long-term success of electrical PV isolation with circular IRE applications, no significant difference in efficacy was found between ablation based on the measurement of electrode interface impedance and ablation using the classical EP approach for determining electrode-tissue contact. Experiences of the first clinical use of MEIS were promising and serve as an important basis for future research.