Effective Pulmonary Vein Isolation Research Articles

Contact-force local impedance algorithm to guide effective pulmonary vein isolation in AF patients: 1-year outcome from an international multicenter clinical setting.

The combination of highly localized impedance (LI) and contact force (CF) may improve tissue characterization and lesion prediction during radiofrequency (RF) pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). We report the outcomes of our acute and long-term clinical evaluation of CF-LI-guided PVI in consecutive AF ablation cases from an international multicenter clinical setting. Three hundred twenty-four consecutive patients from 20 European centers undergoing RF catheter ablation with the Stablepoint™ catheter were enrolled in the CHARISMA registry. Of these, 275 had a minimum follow-up of 1year and were included in the primary analysis. The mean procedure duration was 115 ± 47min, and the mean fluoroscopy time was 9.9 ± 6min. At the end of the procedures, all PVs had been successfully isolated in all study patients. Minor complications were reported in 12 patients (4.4%). At 1year, 36 (13.1%) patients had had an AF recurrence, and freedom from antiarrhythmic drugs and AF recurrence was achieved in 228 (82.9%) patients. The recurrence rate was higher in patients with persistent AF (21/116, 18.1%) than in those with paroxysmal AF (15/159, 9.4%; p = 0.0459). On multivariate logistic analysis adjusted for baseline confounders, only time > 6months from first diagnosis of AF to ablation (HR = 2.93, 95%CI 1.03 to 8.36, p = 0.0459) was independently associated with recurrences. An ablation strategy for PVI guided by CF-LI technology proved safe and effective and resulted in a low recurrence rate of AF over 1-year follow-up, irrespective of the underlying AF type. Catheter Ablation of Arrhythmias with a High-Density Mapping System in Real-World Practice. (CHARISMA). URL: http://clinicaltrials.gov/ Identifier: NCT03793998.

Pulmonary vein isolation with the radiofrequency balloon catheter: long-term results and predictors of ablation success

Abstract Background The novel multielectrode radiofrequency balloon catheter (RFB) has been demonstrated to achieve safe and effective pulmonary vein isolation (PVI). However, data on long-term ablation outcomes is lacking. Purpose This single-centre study aimed to evaluate the efficacy of the RFB beyond 1-year follow-up and define predictors of arrhythmia recurrence. Methods All consecutive patients with symptomatic paroxysmal atrial fibrillation (AF) undergoing first-time PVI with the RFB between January 2021 and November 2022 were prospectively included. Post-ablation remapping was systematically employed to confirm PVI at the end of the procedure. Procedural failure was defined as any atrial tachyarrhythmias (ATas) lasting >30 s occurring during the follow-up after a 3-month blanking period (BP). Patient characteristics, procedural parameters, and ATas recurrence during BP were analysed with respect to ablation outcome. Results A total of 120 consecutive patients (50 female, 42%; mean age 65±12 years) were enrolled. After a mean follow-up of 16.1±7.9 months, ATas recurrence occurred in 30 patients (25%). ATas were adjudicated as AF in 25 patients (83.3%) and as atrial tachycardia/atrial flutter in 5 patients (16.7%). The mean time from the index procedure to ATas recurrence was 203±130 days. A redo procedure was performed in 17 patients (56.7%) and at least one PV reconnection was observed in 12 patients (70.6%). Patients with ATas recurrence presented higher values of body mass index (31.0 ±5.7 vs. 28.1±4.9 kg/m2, p=0.048), larger left atria (43±11 vs. 35±9 ml/m2, p=0.003), and increased rates of ATas recurrence during the BP (53.3% vs. 2.2 %, p<0.001) compared to patients with persistent sinus rhythm. At multivariable Cox regression analysis, left atrial end-systolic volume index and ATas recurrence during the BP were independently associated with procedural failure (HR 1.05, 95%CI 1.00-1.11, p=0.048 and HR 23.88, 95%CI 7.71-73.99, p<0.001, respectively). Conclusion At 16 months follow-up, PVI with the RFB resulted in freedom from arrhythmia relapse in 75% of patients. Left atrial end-systolic volume index and ATas recurrence during the BP were independent predictors of arrhythmia recurrence.ATas-free survivalPredictors of ATas recurrence

Validating peak frequency mapping for atrial far-field electrogram detection: insights from a pulmonary vein isolation model

Abstract Introduction Effective pulmonary vein isolation (PVI) is the cornerstone of AF ablation, and conduction block from the atrium to the pulmonary veins (PV) is the accepted method to demonstrate it. However, far-field electrograms may make challenging to establish whether PVI has been achieved. Purpose This study aimed to evaluate whether peak frequency (PF) mapping can effectively identify far-field electrograms in the superior PVs following a redo PVI procedure. Methods Left atrium and PV activation and voltage bipolar 3D electroanatomical maps were generated using a steerable catheter with a 16-grid-patterned electrode configuration (HD-Grid) during coronary sinus pacing, both before and after the redo PVI. PF maps were developed offline using specialized experimental software. Only reconnected superior PVs from the redo PVI procedure were included in the analysis. Results Twenty consecutive patients (mean age 63±12 years, 12 male) were prospectively enrolled in the study, with 15 presenting reconnected PVs after the redo PVI. Conduction gaps were identified in the superior PVs of 9 patients (7 in the left superior PV, 5 in the right superior PV). Following the redo PVI, both voltage (0.96±1.1 mV vs. 0.49±1.21, P<0.01) and PF (285±134 vs. 153±112 Hz, P<0.001) were significantly reduced in both superior PVs. This reduction was more prominent in the right superior PV (0.83±0.75 vs. 0.20±0.39 mV, 299±159 vs. 132±116 Hz) than in the left superior PV (1.08±1.32 vs. 0.83±1.67 mV, 272±105 vs. 178±101 Hz). High-voltage (>0.3 mV) electrograms remained prevalent in the right (12%) and left (37%) superior PVs after the redo PVI. However, high PF (>250 Hz) electrograms significantly decreased following PVI in both the right (64% before vs. 6% after PVI) and left (66% before vs. 22% after PVI) PVs. Only a small percentage (5.3% in the right PV and 12% in the left PV) of all electrograms exhibited both high voltage and high PF following the PVI (see figure). Conclusion PF mapping proves to be a valuable tool in distinguishing far-field electrograms from atrial activity in the PVs, offering additional insights to complement voltage mapping, particularly in the context of redo PVI procedures.

Contact-force local impedance algorithm to guide effective pulmonary vein isolation in AF patients: 1- year outcome from an international multicenter clinical setting

Abstract Background The combination of highly localized impedance (LI) and contact force (CF) may improve tissue characterization and lesion prediction during radiofrequency (RF) pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). Objective We report the outcomes of our acute and long-term clinical evaluation of CF-LI guided PVI in consecutive AF ablation cases from an international multicenter clinical setting. Methods Consecutive patients (pts) from 16 European centers undergoing de novo AF RF catheter ablation with the Stablepoint catheter endowed of CF and LI measurement capabilities were enrolled in the CHARISMA registry. Ablation was guided by the magnitude and time-course of LI drop during RF delivery. The maximum distance between each ablation spot (center-to-center) was suggested to be ≤6 mm. Procedural endpoint was the achievement of the PVI as assessed by entrance and exit block. Post-ablation, all patients were monitored with ambulatory event monitoring. Additional ECG monitoring was performed as indicated by patient symptoms. Data are reported as mean±SD. Results From a total of 212 consecutive pts, 151 were followed-up for at least 12 months after the procedure and were included in this 1-year outcome analysis (61.6% paroxysmal AF, 38.4% persistent AF, 78.8% de novo procedures, 21.2% redo procedures). Baseline LI was 161.2±19 Ω with LI drop of 21.9±9 Ω (LI drop rate=3.1±2 Ω/s). The first pass isolation rate per vein was 93.3%. LI drop was predicted by baseline LI (r=0.56, 95%CI:0.55 to 0.57, p<0.0001). Effective ablation spots showed both higher baseline LI and LI drop compared with PV gap spots (161.4Ω vs 153.0Ω, p<0.0001 for baseline LI; 22.1Ω vs 14.4Ω, p<0.0001 for LI drop). No steam pops or complications, including atrio-esophageal fistula or tamponade were reported during or after the procedures. At the end of the procedures all PVs were successfully isolated in all study patients. During a median follow-up of 377 [365 – 402] days, 11 (7.3%) patients experienced an early recurrence of AF during the 90-day blanking period. Overall, 21 pts (13.9%) suffered an AF recurrence after the 90-days blanking period (10.8% with paroxysmal AF vs 19% with persistent AF, p=0.226; 10.9% for de novo procedures vs 25.0% for redo procedures, p=0.079). De novo paroxysmal AF pts showed the lowest rate of recurrence (5 out 69 pts, 7.2%). The time to recurrence was comparable among AF type (HR=1.73; 0.73 to 4.05; p=0.210 for persistent vs paroxysmal AF) whereas was shorter in repeated AF ablation procedures (HR=2.49; 1.04 to 5.98; p=0.042 for redo vs de novo procedure). Early recurrence was not associated with late recurrence (HR=2.29; 0.68 to 7.76; p=0.182). Conclusions In our experience, the magnitude of LI drop is predictive of PV segment isolation. An ablation strategy for PVI guided by CF-LI technology was safe and effective, and resulted in a low recurrence rate of AF at 1-year follow-up irrespective of underlying AF type.

Insight into contact force local impedance technology for predicting effective pulmonary vein isolation.

Highly localized impedance (LI) measurements during atrial fibrillation (AF) ablation have the potential to act as a reliable predictor of the durability of the lesions created. We aimed to collect data on the procedural parameters affecting LI-guided ablation in a large multicenter registry. A total of 212 consecutive patients enrolled in the CHARISMA registry and undergoing their first pulmonary vein (PV) isolation for paroxysmal and persistent AF were included. In all, 13,891 radiofrequency (RF) applications of ≥3 s duration were assessed. The first-pass PV isolation rate was 93.3%. A total of 80 PV gaps were detected. At successful ablation spots, baseline LI and absolute LI drop were larger than at PV gap spots (161.4 ± 19 Ω vs. 153.0 ± 13 Ω, p < 0.0001 for baseline LI; 22.1 ± 9 Ω vs. 14.4 ± 5 Ω, p < 0.0001 for LI drop). On the basis of Receiver operating characteristic curve analysis, the ideal LI drop, which predicted successful ablation, was >21 Ω at anterior sites and >18 Ω at posterior sites. There was a non-linear association between the magnitude of LI drop and contact-force (CF) (r = 0.14, 95% CI: 0.13-0.16, p < 0.0001) whereas both CF and LI drop were inversely related with delivery time (DT) (-0.22, -0.23 to -0.20, p < 0.0001 for CF; -0.27, -0.29 to -0.26, p < 0.0001 for LI drop). An LI drop >21 Ω at anterior sites and >18 Ω at posterior sites predicts successful ablation. A higher CF was associated with an increased likelihood of ideal LI drop. The combination of good CF and adequate LI drop allows a significant reduction in RF DT. http://clinicaltrials.gov/, identifier: NCT03793998.

Efficacy and safety of catheter ablation of VT using the QDOT Micro catheter: a propensity-matched dual-center comparison with the thermocool SmartTouch catheter

Abstract Funding Acknowledgements Type of funding sources: None. Background Catheter ablation is an increasingly used treatment option for patients with recurrent ventricular tachycardia (VT) or electrical storm (ES). The QDOT Micro (QDOT) Catheter (Biosense Webster) is a novel radiofrequency ablation catheter that was found to allow rapid and effective pulmonary vein isolation among patients with atrial fibrillation. There is no published data on the safety and efficacy of catheter ablation for VT using the QDOT catheter, and few data allow a direct comparison of different technologies in this setting. Purpose to assess outcomes of CA for VT among patients with structural heart disease using the QDOT catheter, and compare them to those observed with the Thermocool Smarttouch (TC-ST, Biosense Webster) catheter. Methods we conducted a dual-center, observational, prospective study enrolling patients with structural heart disease and recurrent VT/ES undergoing catheter ablation with the QDOT catheter. For comparison, we performed a 1:1 propensity score matching to identify patients who underwent VT CA with the TC-ST catheter, using the nearest neighbor method. Propensity score was based on gender, age, etiology of structural heart disease, left ventricular ejection fraction, electrical storm, and number of previous CAs for VT. The primary efficacy outcome was freedom from recurrent VT, as assessed by implantable defibrillator (ICD) interrogation; the primary safety outcome was in-hospital complications. Results Forty propensity-matched patients were included in the analysis (QDOT, n=20; TC-ST, n=20); baseline clinical characteristics are resumed in Table. After a median follow-up of 7 months, survival free from any recurrent VT measured 74 (95% CI, 57-97)% and 69 (95% CI, 51-93)% in the QDOT and TC-ST groups, respectively (log-rank p=0.54, Figure A), while survival free from ICD shocks was 95 (95% CI, 86-100)% versus 84 (95% CI, 69-100)% (log-rank p=0.26, Figure B). There were no major complications in the QDOT group, while three patients (15%) in the TC-ST had a primary safety event (p=0.23; femoral pseudoaneurysm, n=1; cardiac tamponade, n=1; aortic cusp perforation, n=1). Conclusion In a cohort of patients with structural heart disease and recurrent VT or ES, the novel QDOT ablation catheter had similar efficacy and safety compared to the TC-ST catheter. Interestingly, no major procedural complications were observed with the QDOT catheter, suggesting that this device may be safe even in most challenging patients.

Robotic magnetic navigation guided catheter ablation establishes highly effective pulmonary vein isolation in patients with paroxysmal atrial fibrillation, when compared to conventional techniques

Abstract Funding Acknowledgements Type of funding sources: None. Background Catheter ablation (CA) is an important treatment option for patients with atrial fibrillation (AF). Pulmonary vein isolation (PVI) is a pivotal part of any AF ablative therapy. Currently, there are multiple techniques available to realize PVI, including: manual guided cryoballoon (MAN-CB), manual guided radiofrequency (MAN-RF) and Remote Magnetic Navigation guided RF ablation (RMN-RF). However, there is lack of large prospective trials comparing contemporary RMN-RF with the conventional CA techniques. Purpose This study prospectively analyzed and compared three catheter ablation techniques in patients with paroxysmal AF. Methods This multicenter, prospective study included patients with paroxysmal AF who underwent their first CA procedure with one of the mentioned ablation techniques. Procedural parameters (including procedural efficiency), complication rates and freedom of AF during 12-month follow-up were compared between three study groups defined by the utilized ablation technique. Results A total of 221 patients were included in this study. Total procedure time was significantly shorter in MAN-CB (78±21 min) compared to MAN-RF (115±41 min) and compared to RMN-RF (129±32 min) (P&amp;lt;0.001), whereas it was comparable between the two RF groups. A 3% complication rate was observed which was comparable between all groups. At 12-month follow-up, we observed AF recurrence in 40 patients (19%). AF recurrence was significantly lower in the RMN-RF group (MAN-CB 19 (24%) AF recurrences, MAN-RF 16 (23%), RMN-RF 5 (8%), P=0.045; multivariate HR of RMN-RF on AF recurrence 0.32, 95%-CI 0,12–0.87, P=0.026; with MAN-CB + MAN-RF as the reference group). Conclusion RMN guided PVI results in high freedom of AF in patients with paroxysmal AF, when compared to cryoablation and manual RF ablation. Cryoablation remains the most time efficient ablation technique, whereas RMN has comparable efficiency with manual RF ablation.

Pulmonary vein isolation with the radiofrequency balloon catheter: a single centre prospective study.

The multielectrode radiofrequency balloon catheter (RFB) has been developed to achieve safe and effective pulmonary vein isolation (PVI) for atrial fibrillation (AF) ablation. This single-centre study aimed to evaluate the midterm clinical outcome and predictors of single-shot PVI with the novel RFB. All consecutive patients with symptomatic paroxysmal or persistent AF undergoing first-time PVI with the RFB were prospectively included. Clinical and procedural parameters were systematically collected. The primary safety endpoint was defined as any major periprocedural complications. The primary efficacy endpoint consisted of freedom from any atrial tachyarrhythmias (ATas) lasting >30 s during the follow-up after a 3-month blanking period. Persistent single-shot PVI was defined as PVI achieved with a single RFB application without acute reconnection. A total of 104 consecutive patients (mean age 64.3 ± 11.4 years, 56.7% males) were included. 15 patients (14.4%) presented with persistent AF. The procedure time was 59.0 min with a dwell time of 20.0 min. One major complication occurred in one patient. At a mean follow-up of 10.1 ± 5.3 months, freedom from ATas was 82.9%. ATas occurred in 14 patients, 11/69 patients (15.9%) with paroxysmal AF and 3/13 (23.1%) with persistent AF. The best cut-offs to predict persistent single-shot PVI were impedance drop >19.2 Ω [area under the receiver operator characteristic curve (AUC) 0.74] and temperature rise >11.1° C (AUC 0.77). In a large cohort of patients undergoing PVI with the RFB, the complication rate was 1%. At a mid-term follow-up of 10.1 ± 5.3 months, freedom from ATas was 82.9%. Specific cut-offs of impedance drop and temperature rise may be useful to predict persistent single-shot isolation.

Can lesion parameters predict effective pulmonary vein isolation in very-high-power short-duration radiofrequency ablation?

Abstract Background Pulmonary vein isolation (PVI) is the cornerstone treatment for patients with atrial fibrillation (AF) refractory to medical therapy. Recent advancements have led to the development of contact-force (CF) sensing very-high-power short-duration (vHPSD) radiofrequency (RF) ablation (90W/4 seconds). Previous RF ablation utilized Ablation Index (AI) as a marker of lesion quality to guide the operator which is not utilized in QMODE+ (vHPSD) and thus, there is limited information on effective lesion formation. In this study, we evaluated the correlation between various lesion parameters to identify relationships and potential surrogate markers for effective lesion formation. Moreover, we studied the relationship between different anatomical locations on these parameters to gain further insight. Methods 50 consecutive AF patients (33 males, age 62.0±1.31 years, 66% paroxysmal AF) underwent first time PVI using QMODE+. All wide antral circumferential ablation (WACA) QMODE+ lesions (n=5022) were analyzed for force-time integral (FTI), impedance drop, average CF, maximum temperature attained and anatomical location. The anatomical regions assessed across both left and right WACA were posterior-superior (region 1–2), posterior-inferior (region 3–4), anterior-inferior (region 5–6), anterior-superior (region 7–8) and pulmonary vein carina (region 9). All pulmonary veins (PVs) were checked with pacing maneuvers to examine for gaps in ablation lesions and adenosine for acute pulmonary vein reconnection post-ablation. Results PVI was successful in all patients while a first pass isolation was observed in 26 patients (52%). A total of 5022 lesions were performed with 2461 and 2561 lesions in the left and right WACA respectively. The average CF exhibited positive correlation with maximum temperature attained and impedance drop (p&amp;lt;0.0001) while displaying negative correlation with FTI (p&amp;lt;0.0001) (Figure 1). The PV carina (region 9) of the right WACA had the smallest impedance drop (p&amp;lt;0.0001) while the PV carina of the left WACA exhibited the lowest average CF and temperature attained (p&amp;lt;0.0001) (Figure 2). The highest number of gaps or acute reconnection (12 out of 24 patients) were seen in the region of the left pulmonary vein carina (p&amp;lt;0.0001). Conclusion This is the first study that has investigated the characteristics of vHPSD ablation lesions at different regions in the left atrium. CF was positively correlated with maximum temperature and impedance drop but negatively correlated with FTI. Furthermore, ablation at both right and left PV carina demonstrates lower impedance drop and average CF which may potentially explain the greater prevalence of gaps or reconnections. This study provides detailed insight into the relationship between the anatomical region, contact force, temperature and impedance drop, and will facilitate the optimization for effective vHPSD lesion formation. Funding Acknowledgement Type of funding sources: None.

A novel local impedance algorithm to guide effective pulmonary vein isolation in AF patients: preliminary experience among different voltages of atrial substrate

Abstract Funding Acknowledgements Type of funding sources: None. Background Recently, a novel technology able to measure local tissue impedance (LI) and contact force (CF) aimed at validating ablation endpoints has become available for clinical use. Purpose This analysis explores the relationship between LI parameters, substrate characteristics and AF type during ablation in AF patients. Methods A novel ablation catheter with dedicated algorithm was used to measure LI at the distal electrode. Each ablation point was characterized in terms of RF delivery time, baseline LI and LI drop during ablation according to different voltages (above or below 0.5 mV) of the atrial substrate. Ablation endpoint was PVI as assessed by entrance and exit block with local capture. Data are reported as mean±SD. Results A total of 2032 RFC deliveries from 34 consecutive patients were analyzed (71% paroxysmal AF, 29% persistent AF). All PVs were successfully isolated with an overall procedure time of 128±33min (fluoroscopy time=15.6±9min, RF delivery time=9.6±4s, CF=11.1±7g). The baseline LI was 155±17Ω prior to ablation and 136±14Ω after ablation (p&amp;lt;0.0001, absolute LI drop of 21.0±8Ω) with a LI drop rate equal to 2.8±2Ω/s. Ablation spots were more frequently deployed in high-voltage areas (&amp;gt;0.5mv, n=1240, 61%). Baseline LI and LI drops were both higher when underlying atrial voltages were &amp;gt;0.5mV than when &amp;lt;0.5mV (156±18Ω vs 153.6±16Ω for starting LI, p=0.0032; 22.2±8Ω vs 19.1±8Ω for LI drop, p&amp;lt;0.0001, respectively). No differences were found in terms of both CF and LI after ablation between &amp;gt;0.5mV and &amp;lt;0.5mV (11.0±7g vs 11.2±7g for CF, p=0.3435; 136.4±13Ω vs 135.3±15Ω for ablated tissue LI, p=0.1521, respectively). Low-voltage areas were more frequently detected at ablated spots in persistent AF cases (n=288, 51.9%) than in paroxysmal AF cases (n=504, 35.1%, p&amp;lt;0.0001), however, no differences were found in terms of both baseline LI and LI drop between persistent and paroxysmal AF cases (156.3±17Ω vs 154.6±17Ω for starting LI, p=0.135; 20.7±8Ω vs 21.1±9Ω for LI drop, p=0.1722, respectively). Conclusions LI measurements well distinguished contact with high-voltage areas from low-voltage areas and were able to detect significant differences in LI drop during ablation according to the voltage level.

CA-536-01 PULSED-FIELD ABLATION BASED PULMONARY VEIN ISOLATION: ACUTE SAFETY AND EFFICACY IN A MULTI-CENTER REAL WORLD SCENARIO

Pulsed-field ablation (PFA) is a new energy source to perform pulmonary vein isolation (PVI) by targeted electroporation of cardiomyocytes. Integrated into a single-shot device, PFA has the potential to increase efficacy and safety of PVI compared to thermal energy sources. To assess feasibility, efficacy and safety of PFA for index PVI in a multi-center real world setting. Consecutive patients with symptomatic paroxysmal or persistent atrial fibrillation (AF) underwent PVI using the PFA ablation catheter (Farawave®, Farapulse Inc, Menlo Park, CA, USA) at two high-volume ablation centers. The left atrium was accessed by a single transseptal puncture and PVs were located by selective PV angiographies. 3D voltage mapping of the left atrium was performed before and after PVI. A total of 110 patients (mean age 67±12 years, 62% male, 61% persistent AF) were included. PVI was achieved in all patients by deploying 3567 applications in 435 PVs (8.4±3.1 per vein). Disappearance of PV signals after the first of eight applications was demonstrated in 433/435 PVs (99%). More than eight PFA applications were applied in 23/435 PVs (0.5%) due to difficulties in positioning (3x left superior PV, 7x right superior PV, 7x right inferior PV) or due to reconnection after remapping (2x LIPV, 3x RSPV, 1x RIPV). Mean procedure time was 81±23 minutes including pre- and post PVI high-density voltage mapping. PF catheter left atrial dwell-time was 27±10 min. Left atrial dwell-time reduced from 40 to 24 min during the first 50 procedures at UHZ. Total fluoroscopy time was 16.6±9.2 minutes with a dose area product of 749±79 cGy*cm2. One pericardial tamponade occurred independent of PFA applications and two minor groin complications. No other complications occurred, especially no phrenic nerve palsy, stroke, hemoptysis, atrio-oesophageal fistula or acute symptomatic PV stenosis. In this multi-center real world setting, pulsed field ablation achieves effective pulmonary vein isolation with low complication rates.

Long-term comparisons of atrial fibrillation ablation outcomes with a cryoballoon or laser-balloon: A propensity-matched analysis based on continuous rhythm monitoring

ObjectiveCryoballoon (CB) and laser-balloon (LB) catheter ablation (CA) has been demonstrated to achieve durable and effective pulmonary vein isolation (PVI). Only one head-to-head comparison with an intermittent rhythm monitor strategy is currently available. The aim of this study was to compare acute and long-term outcomes of CB and LB atrial fibrillation ablation procedures, by using a continuous rhythm monitoring strategy. MethodsThis was a prospective two-arm nonrandomized propensity-matched observational trial that compared the outcomes of atrial fibrillation (AF) ablation using LB and CB techniques. To evaluate AF recurrences, an implantable cardiac monitor (ICM) was implanted before hospital discharge to detect atrial tachyarrhythmia (ATA) recurrences. ResultsA total of 110 propensity-matched patients undergoing AF ablation with an LB (n = 55) or with a CB system (n = 55) were enrolled (paroxysmal AF 57.3%). Procedural time (LB: 87 [73–104] vs. CB 90 [70–130] min; p = 0.264) and fluoroscopy time did not differ. No differences in ATA recurrences were observed at 12 months (LB–30.9% vs. CB–29.1% and LB–45.5% vs. CB–38.2%; log-rank 0.539). As for AF burden, the 12-month median was 0 [0-1] vs. 0 [0-3]% (p = 0.127) in the LB and CB groups, respectively. When considering only PeAF patients, the median 12-month ATA burden was 26 [18.5-40.5] vs. 29 [26-35]% (p = 0.919) for the LB and CB patients, respectively. ConclusionIn a propensity-matched cohort undergoing AF ablation, arrhythmia outcomes assessed by continuous rhythm monitoring did not differ between LB and CB, with an overall low ATA burden. The only predictor of recurrences was persistent AF. There was no difference in procedure or fluoroscopy time.

Mapping Technologies for Catheter Ablation of Atrial Fibrillation Beyond Pulmonary Vein Isolation.

Catheter ablation remains the most effective and relatively minimally invasive therapy for rhythm control in patients with AF. Ablation has consistently shown a reduction of arrhythmia-related symptoms and significant improvement in patients’ quality of life compared with medical treatment. The ablation strategy relies on a well-established anatomical approach of effective pulmonary vein isolation. Additional anatomical targets have been reported with the aim of increasing procedure success in complex substrates. However, larger ablated areas with uncertainty of targeting relevant regions for AF initiation or maintenance are not exempt from the potential risk of complications and pro-arrhythmia. Recent developments in mapping tools and computational methods for advanced signal processing during AF have reported novel strategies to identify atrial regions associated with AF maintenance. These novel tools – although mainly limited to research series – represent a significant step forward towards the understanding of complex patterns of propagation during AF and the potential achievement of patient-tailored AF ablation strategies for the near future.

Occlusion tool software for pulmonary vein occlusion verification in atrial fibrillation cryoballoon ablation.

Optimal pulmonary vein (PV) occlusion, usually verified with selective contrast injection, is mandatory to obtain an effective PV isolation during cryoballoon (CB) ablation. The purpose of this study was to verify the feasibility and the accuracy of a new dielectric sensing system in assessing PV occlusion during CB ablation in patients with atrial fibrillation (AF). We enrolled 28 consecutive patients with paroxysmal or persistent AF. After transseptal access, a detailed image reconstruction of left atrium and PVs was achieved with an octapolar or decapolar mapping catheter (Achieve catheter, Medtronic Inc.) and KODEX-EPD system (EPD Solutions, a Philips company). The degree of PV occlusion with the inflated Arctic Front Advance Cryoballoon (Medtronic Inc.) was verified using the new "occlusion tool" software module (EPD Solutions, a Philips company) and compared to an angiogram obtained with contrast medium injection in each PV. A total of 105 PV CB occlusion were tested. The new occlusion tool software module showed a 91% sensitivity and 76% specificity in assessing a complete PV occlusion verified with contrast medium injection. The positive predictive value was 80%, and the negative predictive value was 88.6%. Mean procedure time was 81± 17 minutes. Mean fluoroscopy time was 6± 2 minutes. No 30-day complications were observed. The new dielectric imaging system was able to assess the degree of PV occlusion during a CB ablation with good sensitivity and specificity.

Novel occlusion tool software for pulmonary vein occlusion verification in atrial fibrillation cryoballoon ablation

Abstract Background Optimal pulmonary vein (PV) occlusion, checked with selective contrast injection, is mandatory to obtain an effective PV isolation with a cryoballoon. Purpose The purpose of this study was to verify the feasibility of a new dielectric sensing system in assessing PV occlusion during cryoballoon ablation in patients with atrial fibrillation (AF). Methods We enrolled 25 consecutive patients with paroxysmal or persistent AF. After transseptal access a detailed image reconstruction of left atrium and PVs was achieved with a decapolar circular mapping catheter and a novel dielectric imaging system. The degree of PV occlusion with the inflated cryoballoon catheter was verified by a new occlusion tool software of the dielectric imaging system and compared to the angiography with dye injection in each PV. Results A total of 114 PV cryoballoon occlusion were tested. The new occlusion tool software showed a 91.7% sensitivity and 81.5% specificity in assessing a complete PV occlusion verified with dye injection. The positive predictive value was 84.6% and the negative predictive value was 89.8%. Acute isolation was achieved in all PVs. No 30 days complications were observed. Conclusion This is the first study that demonstrates the feasibility of a new occlusion tool software, using the novel dielectric imaging system, in verifying the degree of PV occlusion during cryoballoon ablation. Funding Acknowledgement Type of funding source: None

A novel local impedance algorithm to guide effective pulmonary vein isolation in AF patients: 1-year outcome from the CHARISMA Study

Abstract Background Recently, a novel technology able to measure local tissue impedance (LI) providing a measure of tissue characteristics aimed at validating confidently ablation endpoints has become available for clinical use. Purpose We report the outcomes of our acute and long-term clinical evaluation of this algorithm in consecutive atrial fibrillation ablation cases. Methods Consecutive patients (pts) undergoing AF ablation at 6 Italian centers were included in the CHARISMA registry. A novel RF ablation catheter and a dedicated algorithm were used to measure LI through the distal catheter's electrode. The ablation was guided by looking at the magnitude and time course of impedance drop during RF delivery. The maximum distance between each ablation spot (center-to-center) was suggested to be ≤4 mm. RF applications were targeted to a LI drop of 10 Ω and RF applications were stopped when a maximum cutoff LI drop of &amp;lt;40 Ω was observed. Successful single RF ablation was defined according with a reduction of signal voltage (RedV) by at least 50% and inability to capture local tissue on pacing. Ablation endpoint was PVI as assessed by entrance and exit block. Post-ablation, all pts were monitored with ambulatory event monitoring, as well as Holter monitoring at 3, 6, and 12 months post-ablation. Additional ECG monitoring was performed as indicated by patient symptoms. Results A total of 1914 point by point first pass RF applications &amp;gt;10 s performed around PVs were analyzed from 98 pts (mean age = 61±11 years, 69% male, 55% paroxysmal AF, 45% persistent AF, 60% de novo procedures, 40% redo procedures). The mean LI was 105±15Ω prior to ablation and 92±13Ω after ablation (p&amp;lt;0.0001, mean absolute LI drop of 12.7±8Ω) during a median RF delivery time of 22 [17–31] sec. Effective ablation spots (88%) showed a higher absolute impedance drop (13.6±8Ω at effective RedV vs 6±3Ω at ineffective RedV, p&amp;lt;0.0001) compared with ineffective sites (12%). No steam pops or complications, including atrio-esophageal fistula or tamponade were reported during or after the procedures. At the end of the procedures all PVs were successfully isolated in all study pts. During a median follow-up of 369 [287–446] days, 13 pts (13.2%) developed an AF/AT recurrence after the 90-days blanking period (9.2% with paroxysmal vs 18% with persistent AF, p=0.239; 8.5% for de novo vs 20.5% for redo procedures, p=0.127). The time to recurrence was comparable among AF type (HR=1.97; 0.66 to 5.86; log-rank p=0.2265 for persistent vs paroxysmal AF) and procedural type (HR=2.56; 0.84 to 7.82; log-rank p=0.087 for redo vs de novo procedure) Conclusions In our experience, the magnitude of the LI drop during RF delivery was associated with effective lesion formation. An ablation strategy for PVI guided by LI technology was safe and effective, and resulted in a very low recurrence rate of AF at 1-year follow-up irrespective of paroxysmal/persistent AF type or de novo/redo procedure. Funding Acknowledgement Type of funding source: None

A novel local impedance algorithm to guide effective pulmonary vein isolation in atrial fibrillation patients: Preliminary experience across different ablation sites from the CHARISMA pilot study.

Recently, a novel technology able to measure local impedance (LI) and tissue characteristics has been made available for clinical use. This analysis explores the relationships among LI and generator impedance (GI) parameters in atrial fibrillation (AF) patients. Characterization of LI among different ablation spots and procedural success were also evaluated. Consecutive patients undergoing AF ablation from the CHARISMA registry at five Italian centers were included. A novel radiofrequency (RF) ablation catheter with a dedicated algorithm (DIRECTSENSE™) was used to measure LI and to guide ablation. The ablation endpoint was pulmonary vein (PV) isolation. We analyzed 2219 ablation spots created around PVs in 46 patients for AF ablation. The mean baseline tissue impedance was 105.8 ± 14 Ω for LI versus 91.8 ± 10 Ω for GI (p < .0001). Baseline impedance was homogenous across the PV sites and proved higher in high-voltage areas than in intermediate- and low-voltage areas and the blood pool (p < .001). Both LI and GI displayed a significant drop after RF delivery, and absolute LI drop values were significantly larger than GI drop values (14 ± 8 vs. 3.7 ± 5 Ω, p < .0001). Every 5-point increment in LI drop was associated with successful ablation (odds ratio = 3.05, 95% confidence interval: 2.3-4.1, p < .0001). Conversely, GI drops were not significantly different comparing successful versus unsuccessful sites (3.7 ± 5 vs. 2.8 ± 4 Ω, p = .1099). No steam pops or major complications occurred during or after the procedures. By the end of the procedures, all PVs had been successfully isolated in all patients. The magnitude of the LI drop was more closely associated with effective lesion formation than the GI drop.

Anatomic predictors of recurrence after cryoablation for atrial fibrillation: a computed tomography based composite score.

Effective pulmonary vein isolation (PVI) with cryoablation depends on adequate occlusion of pulmonary veins (PV) by the cryoballoon and is therefore likely to be affected by PV and left atrial (LA) anatomical characteristics and variants. Thus, the objective of this study was to investigate the effect of LA and PV anatomy, evaluated by computed tomography (CT), on acute and long-term outcomes of cryoablation for atrial fibrillation (AF). Fifty-eight patients (64.72+9.44years, 60.3% male) undergoing cryoablation for paroxysmal or early persistent AF were included. Pre-procedural CT images were analyzed to evaluate LA dimensions and PV anatomical characteristics. Predictors of recurrence were identified using regression analysis. 60.3% of patients had two PVs on each side with separate ostia, whereas 29.3% and 10.3% had right middle and left common PVs, respectively. The following anatomic characteristics were found to be independent predictors of recurrence: right superior PV ostial max:min diameter ratio > 1.32, left superior PV ostial max:min diameter ratio > 1.2, right superior PV antral circumference > 69.1mm, right inferior PV antral circumference > 61.38mm, right superior PV angle > 22.7°. Using these factors, LA diameter and right middle PV, a scoring model was created for prediction of "unfavorable" LA-PV anatomy (AUC = 0.867, p = 0.000009, score range = 0-7). Score of ≥ 4 predicted need for longer cryoenergy ablation (p = 0.039) and more frequent switch to radiofrequency energy (p = 0.066) to achieve PVI, and had a sensitivity of 83.3% and specificity of 82.5% to predict clinical recurrence. CT-based scoring system is useful to identify "unfavorable" anatomy prior to cryo-PVI, which can result in procedural difficulty and poor outcomes.

Emerging Technologies for Pulmonary Vein Isolation

Atrial fibrillation is the most common sustained cardiac arrhythmia and is associated with considerable morbidity and mortality. Electrically isolating the pulmonary veins from the left atrium by catheter ablation is superior to antiarrhythmic drug therapy for maintaining sinus rhythm, but its success varies depending on multiple factors, including arrhythmic burden. Although procedural outcomes have improved over the years, further gains are limited by a seemingly zero-sum relationship between effectiveness and safety, which is largely a product of the available technologies. Current energies used to create contiguous, transmural, and durable atrial lesions can result in serious complications if they reach the esophagus or phrenic nerve, for instance-structures that can be adjacent to the atrial myocardium, often within millimeters of the energy source. Consequently, high rates of pulmonary vein-left atrium reconnections are consistently seen in clinical studies and in clinical practice as operators appropriately forgo ablation effectiveness to protect patients from harm. However, as ablative technologies evolve to circumvent this stalemate, safer, and more effective pulmonary vein isolation seems increasingly realistic. Furthermore, the innovative nature of these technologies raises the prospect of markedly improved procedural efficiency, which could increase patient comfort, reduce operator occupational injuries, and enhance the use of health resources-all of which are increasingly important considerations particularly as the demand for catheter ablation for atrial fibrillation continues to rise. We herein review 3 promising candidate ablation technologies with the potential to revolutionize the management of patients with atrial fibrillation: electroporation (pulsed-field ablation), expandable lattice-tip radiofrequency ablation/electroporation, and ultra-low temperature cryoablation.

Recurrent persistent atrial fibrillation after effective pulmonary vein isolation: What else?

Pulmonary vein isolation (PVI) is the mainstay of every atrial fibrillation (AF) ablation procedure. However, it is still debated in the literature whether PVI alone is sufficient to achieve long-term freedom from atrial tachyarrhythmias in patients with non-paroxysmal AF. Hereby, we discuss the hypothetical clinical scenario of a patient with AF relapse 6 months after PVI in whom all pulmonary veins are electrically silent at the time of repeat ablation.