Second-generation cryoballoon ablation for recurrent atrial fibrillation after an index procedure with radiofrequency versus cryo: Different pulmonary vein reconnection patterns but similar long-term outcome-Results of a multicenter analysis

Durability of Ultra-Low Temperature Cryoablation Lesions in Atrial Fibrillation: Insights From Repeat Ablation Procedures

BACKGROUND

Ultra-low temperature cryoablation (ULTC) is a technique designed to rapidly cool cardiac tissue to extremely low temperatures, enabling the creation of ablation lesions for the treatment of atrial fibrillation (AF). Prior studies have demonstrated low rates of arrhythmia recurrence, but little is known about ablation lesion durability.

METHODS

Patients undergoing repeat ablation were selected from the CryoCure2 (NCT02839304) and iCLAS PMCF(NCT05416086) studies. Baseline patient and ULTC procedure characteristics were evaluated. During repeat ablation, ULTC ablation lesions were assessed for electrical block, including segment-based assessment of pulmonary vein (PV) ablation lesions. Arrhythmia outcomes after repeat ablation were evaluated.

RESULTS

Twenty-five patients were included in the cohort: Age 68 ± 7 years, male 68%, persistent AF 68%, LAVI 42 ± 24 mL/m2. During index procedure, ULTC was used to target the PVs in all patients, the left atrium posterior wall (LAPW) in 15 patients, the lateral mitral isthmus (LMI) in five patients and the cavotricuspid isthmus (CTI) in two patients. At repeat ablation, PV reconnection was observed in 21/25 patients (55/100 PVs reconnected), and reconnection occurred most often in the anterior segments of the left PVs. The LAPW lesion was incomplete in 4/15 patients, the LMI in 3/5 and the CTI in 1/2. After repeat ablation, 10/25 patients had arrhythmia recurrence.

CONCLUSION

Reconnection of ablation targets during repeat ablation for arrhythmia recurrence following ULTC occurred at rates comparable to those observed with conventional thermal ablation modalities. The anterior side of the left PVs appears to be reconnected most often.

Redo ablation procedures to treat recurrent atrial arrhythmias via a pentaspline pulsed field ablation catheter: a prospective, multicenter experience

BACKGROUND

Patients undergoing atrial fibrillation (AF) catheter ablation may require redo procedures involving pulmonary vein (PV) re-isolation and/or ablation of extra-PV sites. Pulsed field ablation (PFA) offers a highly selective energy source for cardiac tissue, with the potential to reduce collateral damage to adjacent structures. This study aimed to evaluate the feasibility and efficacy of redo ablation using a pentaspline PFA system.

METHODS

Patients undergoing redo procedures with a pentaspline PFA system at three international centers were enrolled. A workflow was established based on rhythm at presentation: sinus rhythm (Group 1), atrial flutter/atrial tachycardia (Group 2), or AF (Group 3). Propensity score matching was used for comparison between PFA- and RF-based redo ablations.

RESULTS

A total of 117 patients were included (Group 1: 64, Group 2: 18, Group 3: 35). PV re-isolation was required in 71.9% and 72.2% of Group 1 and 2 patients, respectively. PFA terminated all cases of non-cavotricuspid isthmus dependent flutter and 45.7% of cases of AF. One major complication (0.9%; frontal cerebral hematoma) was documented. Freedom from atrial tachyarrhythmias at 12 months was 78.3% (95% CI 69.6-84.8%) without statistically significant differences among groups (Group 1: 85.7%; Group 2: 77%; Group 3: 65.5%; p = 0.053). PFA led to similar arrhythmia freedom compared to RF, but with significantly shorter procedural and dwelling times.

CONCLUSION

The adoption of a pentaspline PFA system for repeat ablation procedures was feasible, safe, and effective at 1-year follow-up. No clinical differences were observed between PFA and RF; however, redo PFA cases were significantly shorter.

Durability of pulmonary vein isolation for atrial fibrillation: a meta-analysis and systematic review

AIMS

Pulmonary vein isolation (PVI) plays a central role in the interventional treatment of atrial fibrillation (AF). Uncertainties remain about the durability of ablation lesions from different energy sources. We aimed to systematically review the durability of ablation lesions associated with various PVI-techniques using different energy sources for the treatment of AF.

METHODS AND RESULTS

Structured systematic database search for articles published between January 2010 and January 2023 reporting PVI-lesion durability as evaluated in the overall cohort through repeat invasive remapping during follow-up. Studies evaluating only a proportion of the initial cohort in redo procedures were excluded. A total of 19 studies investigating 1050 patients (mean age 60 years, 31% women, time to remap 2-7 months) were included. In a pooled analysis, 99.7% of the PVs and 99.4% of patients were successfully ablated at baseline and 75.5% of the PVs remained isolated and 51% of the patients had all PVs persistently isolated at follow-up across all energy sources. In a pooled analysis of the percentages of PVs durably isolated during follow-up, the estimates of RFA were the lowest of all energy sources at 71% (95% CI 69-73, 11 studies), but comparable with cryoballoon (79%, 95%CI 74-83, 3 studies). Higher durability percentages were reported in PVs ablated with laser-balloon (84%, 95%CI 78-89, one study) and PFA (87%, 95%CI 84-90, 2 studies).

CONCLUSION

We observed no significant difference in the durability of the ablation lesions of the four evaluated energies after adjusting for procedural and baseline populational characteristics.

Comparison of pulmonary vein isolation using cryoballoon, high-power short-duration, and conventional radiofrequency ablation for atrial fibrillation: a propensity score-weighted study

Background

The comparative efficacy, saftey, and heart rate variability (HRV) parameters after pulmonary vein isolation using cryoballoon (Cryo-PVI), high-power short-duration (HPSD-PVI), and conventional radiofrequency ablation (conventional-PVI) for atrial fibrillation (AF) is unclear.

Materials and methods

In this propensity score-weighted, retrospective analysis of a single-center cohort, we analyzed 3,395 patients (26.2% female, 74.5% paroxysmal AF) who underwent AF catheter ablation without an empirical left atrial ablation. Procedural factors, recurrence rates, complication rates, and the post-procedural HRV parameters were compared across the Cryo-PVI (n = 625), HPSD-PVI (n = 748), and conventional-PVI (n = 2,022) groups.

Results

Despite the shortest procedural time in the Cryo-PVI group (74 min for Cryo-PVI vs. 104 min for HPSD-PVI vs. 153 min for conventional-PVI, p < 0.001), the major complication (p = 0.906) and clinical recurrence rates were similar across the three ablation groups (weighted log-rank, p = 0.824). However, the Cryo-PVI group was associated with a significantly lower risk of recurrent AF in patients with paroxysmal AF [weighted hazard ratio (WHR) 0.57, 95% confidence interval (CI) 0.37-0.86], whereas it was associated with a higher risk of recurrent AF in patients with persistent AF (WHR 1.41, 95% CI 1.06-1.89, p for interaction of <0.001) compared with the conventional-PVI group. In the subgroup analysis for the HRV, the Cryo-PVI group had the highest low-frequency-to-high-frequency ratio at 1-year post-procedure, whereas the HPSD-PVI group had the lowest low-frequency-to-high-frequency ratio at 1-year post-procedure (p < 0.001).

Conclusions

The Cryo-PVI group had better rhythm outcomes in patients with paroxysmal AF but worse rhythm outcomes in patients with persistent AF and a higher long-term post-procedural sympathetic nervous activity and sympatho-vagal balance compared with the conventional-PVI group.

Chronic Ablation Lesions after Cryoballoon and Hot Balloon Ablation of Atrial Fibrillation

BACKGROUND

Chronological changes in ablation lesions after cryoballoon ablation (CBA) and hot balloon ablation (HBA) of atrial fibrillation (AF) remain unclear.

METHODS

Of 90 patients who underwent initial balloon-based catheter ablation of AF and cardiac magnetic resonance imaging (cMRI) 3 months after ablation, data from 48 propensity score-matched patients (24 per group; 34 males; age 62±10 years) were analyzed. High-density pulmonary vein-left antrum (PV-LA) voltage mapping was performed after PV isolation, and low voltage areas around the PV ostia were defined as the total acute ablation lesion area (cm²). cMRI-derived dense fibrotic tissue localized around PVs was defined as the total chronic ablation lesion area (cm²). The percentage of total ablation lesion areas to total PV-LA surface area (%ablation lesion) was calculated during each phase, and %acute ablation lesion and %chronic ablation lesion areas were compared in patients who had undergone CBA and HBA.

RESULTS

The %acute ablation lesion area was larger for the CBA group than for the HBA group (30.8±5.8% vs. 23.0±5.5%, p < 0.001). There was no difference in %chronic cMRI-derived ablation lesion area (24.8±10.8% vs. 21.1±11.6%, p = 0.26) between groups. The rates of chronic AF recurrence were 12.5% and 8.3%, respectively (p = 0.45; log-rank test). LA volume and LA surface area were strongly associated with AF recurrence, but %chronic ablation lesion area was not (27±8% vs. 23±12%, p = 0.39).

CONCLUSION

Large acute ablation lesions after CBA were smaller during the chronic phase. The size of chronic ablation lesions and the rate of AF recurrence were both similar for CBA and HBA.

Atrial fibrillation ablation: the position of computed tomography in pre-procedural imaging

Atrial fibrillation (AF) is the most common supraventricular arrhythmia. Despite significant advances in its treatment, it still remains one of the leading causes of cardiovascular morbidity and mortality. In the last two decades, pulmonary vein isolation (PVI) was developed as the most effective treatment option. The reported effectiveness of a single ablation procedure ranges from 40% to 69% with single, and up to 88% with repeated procedures, with acceptable safety profile. The PubMed database was searched, using terms including ‘atrial fibrillation ablation’, ‘pulmonary vein isolation’, ‘computed tomography’, ‘pulmonary vein anatomy’ and ‘ovality index’. Papers were reviewed for relevance and scientific merit. Different imaging techniques are used for pre-procedural assessment of left atrial (LA) anatomy, of which computed tomography (CT) is the most common. It allows assessing pulmonary vein (PV) anatomy, the LA wall thickness in different regions and the left atrial appendage (LAA) anatomy, together with excluding the presence of intracardiac thrombi. Pre-procedural PVs imaging is important regardless of the selected ablation technique, however, cryoballoon (CB) ablation seems to be particularly anatomy-dependent. Additionally, CT also permits assessment of several PVs characteristics (geometry, dimensions, angulations, the ostium area, orientation and ovality index (OI), which are essential for the patients’ qualification and designing the strategy of AF ablation. In this paper, we have reviewed the role of CT imaging in patients undergoing ablation procedure due to recurrent/symptomatic atrial fibrillation. Moreover, we discussed the relevant literature.

A frozen decade: Ten years outcome of atrial fibrillation ablation using a single shot device for pulmonary vein isolation

AIMS

Cryoballoon-guided pulmonary vein isolation (CB-PVI) for symptomatic atrial fibrillation (AF) has become an established treatment option with encouraging results in terms of safety and efficacy. Data reporting on long-term data beyond a follow-up (FU) period of five years is scarce. This prospective study aimed to evaluate very long-term outcome after CB-PVI for AF.

METHODS

Data from consecutive patients treated with CB-PVI for symptomatic and drug refractory AF between 2005 and 2012 were analyzed. Patients with a FU of ≥9 years after index CB-PVI were included. All patients were continuously followed-up in our outpatient clinic. Arrhythmia recurrence was defined as AF or atrial tachycardia (AT) lasting >30s beyond a three-month blanking period.

RESULTS

A total of 385 patients (71% male) were included. Mean age was 58±10 years and paroxysmal AF was present in 93% of patients. Mean FU duration was 124±24 months. At the end of the observational period, 73% of all patients were in stable sinus rhythm after a mean of 2±0.8 ablation procedures. Patients with AF/AT recurrence were older (60±8vs.57±10 years; p=0.019), had a higher CHA₂ DS₂ -Vasc Score (2.47±1.46vs.1.98±1.50; p=0.01) and presented with a larger LA-diameter (43±5.6vs40±5.1 mm; p=0.002). The LA-diameter was also a significant predictor for AF/AT recurrence after CB-PVI (Odds Ratio: 0.939,95% CI [0.886, 0.992], p=0.03).

CONCLUSIONS

CB-PVI as index procedure for AF ablation resulted in favorable long-term outcome in symptomatic AF. CB-PVI might be recommended as interventional therapy in patients with lower LA remodeling. This article is protected by copyright. All rights reserved.

Radiofrequency Versus Cryoballoon Catheter Ablation for Paroxysmal Atrial Fibrillation: Durability of Pulmonary Vein Isolation and Effect on Atrial Fibrillation Burden: The RACE-AF Randomized Controlled Trial

Supplemental Digital Content is available in the text.

Background:

Recurrent paroxysmal atrial fibrillation (AF) after catheter ablation is presumably caused by failure to achieve durable pulmonary vein isolation (PVI). The primary methods of PVI are radiofrequency catheter ablation (RF) and cryoballoon catheter ablation (CRYO), but these methods have not been directly compared with respect to PVI durability and the effect thereof on AF burden (% of time in AF).

Methods:

Accordingly, we performed a randomized trial including 98 patients (68% male, 61 [55–67] years) with paroxysmal AF assigned 1:1 to PVI by contact-force sensing, irrigated radiofrequency catheter, or second-generation cryoballoon catheter. Implantable cardiac monitors were inserted ≥1 month before PVI for assessment of AF burden and recurrence, and all patients, irrespective of AF recurrence, underwent a second procedure 4 to 6 months after PVI to determine PVI durability.

Results:

In the second procedure, 152 out of 199 (76%) pulmonary veins (PVs) were found durably isolated after RF and 161 out of 200 (81%) after CRYO (P=0.32), corresponding to durable isolation of all veins in 47% of patients in both groups (P=1.0). Median AF burden before PVI was 5.4% (interquartile range, 0.5%–13.0%) versus 4.0% (0.6%–18.1%), RF versus CRYO (P=0.71), and reduced to 0.0% (0.0%–0.1%) and 0.0% (0.0%–0.5%), respectively (P=0.58)—a reduction of 99.9% (92.9%–100.0%) and 99.3% (85.9%–100.0%; P=0.36). AF burden after PVI significantly correlated to the number of durably isolated PVs (P<0.01), but 9 out of 45 (20%) patients with durable isolation of all veins had recurrence of AF within 4 to 6 months after PVI (excluding a 3-month blanking period).

Conclusions:

PVI by RF and CRYO produce similar moderate to high PVI durability. Both treatments lead to marked reductions in AF burden, which is related to the number of durably isolated PVs. However, for one-fifth of paroxysmal AF patients, complete and durable PVI was not sufficient to prevent even short-term AF recurrence.

Registration:

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03805555.

Approach to recurrence of atrial fibrillation after catheter ablation

Atrial fibrillation (AF) is the most commonly observed sustained rhythm disorder during adult ages. Since it has been shown that the ectopic beat initiating AF is usually caused by pulmonary veins, AF ablation has become the mainstay of therapy worldwide. Cryoballoon and radiofrequency ablation are the most commonly used methods in today's technologies. However, despite technological advances, the success of a single procedure in AF ablation is still limited and multiple procedures may be required for the majority of patients. In cases in which a redo ablation is required, pulmonary vein isolation is still the main target, but non-pulmonary vein targets should also be considered in AF episodes that continue despite multiple ablations. Many issues are still unclear as to which energy to choose in the first procedure, and what ablation strategy will be utilized when a redo ablation is required. The studies on this subject are very limited but, it still seems feasible and a rational approach to utilize a customized treatment strategy in each specific patient subgroup.

Outcomes of atrial fibrillation ablation program based on single-shot techniques

Introduction

Single-shot techniques such as cryoballoon and multipolar phased pulmonary vein ablation catheter (PVAC) are an alternative to the point-by-point radiofrequency method for atrial fibrillation (AF) ablation. However, there is a lack of data concerning sequential use of single-shot techniques, that is, for both the index and redo ablation.

Aim

To assess long-term outcomes of the ‘single-shot techniques only’ AF ablation strategy.

Material and methods

We analyzed all consecutive AF ablations performed over a 10-year period (2009–2019) in a center where a ‘single-shot technique only’ principle was followed from the start of the AF ablation program. Kaplan-Meier AF-free survival curves were calculated and complications were assessed on the basis of our prospectively maintained database.

Results

A total of 597 patients (62.4 ±12.5 years) with paroxysmal (78.1%) or persistent (21.9%) AF entered the study and 655 AF ablation procedures were performed. In 96.5% of redos (n = 58) a different technique (mostly PVAC) was used than for the index ablation (mostly cryoballoon). The Kaplan-Meier estimates of 1, 2 and 5 years freedom from AF were 78.2%, 69.2%, and 56.0%, for the index ablation, and 80.3%, 76.1% and 68.3%, for the redo, respectively. The minor and major complication rates were 8.1%, and 4.0%, respectively.

Conclusions

An AF ablation program based solely on sequential use of two different single-shot techniques for both index and redo procedures is safe and effective. These observations might have important practical implications for new operators/centers starting AF ablation programs and for use of single-shot techniques for redo procedures.

Is the time of atrial fibrillation recurrence after cryoballoon ablation of paroxysmal atrial fibrillation influenced by the pattern of PV reconnections?

BACKGROUND

Pulmonary vein isolation (PVI) with 2nd-generation cryoballoon (CB) has been shown to be effective in the treatment of paroxysmal atrial fibrillation (AF). We describe pulmonary vein (PV) reconnection at repeat ablation in patients with AF recurrence after CB PVI and analyze the correlation between the time of AF recurrence and the observed PV reconnection patterns.

METHODS

Sixty-six patients undergoing a redo PVI for recurrent AF were enrolled 9.1 ± 2.6 months after the initial CB PVI procedure.

RESULTS

Ninety-two percent had PV reconnections with a mean of 1.97 ± 0.8 reconnected PVs/patient, and 52% of formerly isolated PVs were found reconnected. The highest reconnected rates were observed for left superior PVs (67%). Fifty-three percent of the patients had 2 reconnected PVs, no patient had all PVs reconnected, and 8% were without PV reconnection. There was a significant negative correlation between the time of AF recurrences and the extent of PV reconnections at redo PVI for patients with proven PV reconnection in more than one PV (R = 0.52, p < 0.001), while all patients without PV reconnection had AF recurrences within the first 9 months after PVI.

CONCLUSIONS

At redo ablation, most patients with recurrence of AF after CB PVI had PV reconnection(s). Patients with PV reconnection(s) showed a negative correlation between the number of reconnected PVs and the time of AF recurrence with more extensive PV reconnections resulting in earlier PV recurrences after the blanking period. Patients without PV reconnection experienced early AF recurrences, indicating non-PV triggers contributing for paroxysmal AF recurrences in these patients.

Is the Time of Atrial Fibrillation Recurrence After Duty-Cycled Radiofrequency Ablation Affected by the Pattern of Pulmonary Vein Reconnections?

Background

Pulmonary vein isolation (PVI) with multielectrode duty-cycled radiofrequency (PVAC) has been shown to be effective in the treatment of atrial fibrillation (AF). We describe pulmonary vein (PV) reconnection at repeat ablation in patients with AF recurrence after PVAC PVI and analyze the correlation between the time of AF recurrence and the observed PV reconnection patterns.

Methods

Eighty-five patients undergoing a redo PVI for recurrent AF 9.2 ± 3.8 months after an initial PVAC PVI procedure was retrospectively enrolled.

Results

A total of 93% had PV reconnections with a mean of 2.97 ± 1.2 reconnected PVs/patients and 75% of formerly isolated PVs were found reconnected. The highest reconnection rates (94%) were observed for left common trunks (CTs). A total of 33% patients had three and four reconnected PVs, respectively, while 7% were without PV reconnection. There was a moderate but significant negative correlation between the time of AF recurrences and the extending of PV reconnections at redo PVI for patients with proven PV reconnection (r = -0.32, P = 0.005), whereas five out of six patients without PV reconnection had recurrences within the first 9 months after PVI.

Conclusions

At redo ablation most patients with recurrence of AF after PVAC PVI had PV reconnection(s). Patients with PV reconnection(s) showed a moderate negative correlation between the number of reconnected PVs and the time of AF recurrence with more extensive PV reconnections resulting in earlier PV recurrences after the blanking period. Patients without PV reconnection experienced early AF recurrences, indicating non-PV triggers contribute to AF recurrences in these patients.

Comparison of pulmonary vein reconnection patterns after multielectrode phased radiofrequency- and cryoballoon ablation of atrial fibrillation

Background

Pulmonary vein isolation (PVI) using phased radiofrequency (RF) energy has been shown to be effective in the treatment of atrial fibrillation (AF).

Methods

We characterize and compare pulmonary vein (PV) reconnection at repeat ablation in patients with AF after initially successful PVI using phased RF technology (PVAC) or 2nd generation cryoballoon (CB). Eighty five patients undergoing redo PVI using multielectrode PVAC phased RF catheter and 66 patients after CB PVI were enrolled 9.7 ± 3.4 months after the initial ablation procedure.

Results

The percentage of patients with PV reconnection(s) was comparably high between both groups (93% PVAC and 92% CB). However, 75% of all PVs and left common trunks (CTs) isolated with PVAC were reconnected, compared with 52% reconnections after CB PVI (p < 0.001). A mean of 2.79 ± 1.2 PVs and CTs/patient were reconnected after PVAC PVI compared with 1.97 ± 0.8 in CB patients, p < 0.0001. No patients in the CB group had 4 reconnected PVs, while this pattern of reconnection was observed in 33% in the PVAC group (p < 0.0001). The percentage of patients in the PVAC group with ≥3 reconnected PVs was significantly higher compared with CB patients (56 patients (66%) vs. 17 patients (26%), p < 0.0001), while the percentage of patients with no PV reconnection was comparably low in PVAC and CB patients (7 and 8%, respectively). CTs were most frequently reconnected after PVAC PVI (94%) and left superior PVs after CB ablation (67%), respectively.

Conclusions

The number of patients with recurrent AF and PV reconnection(s) at redo PVI was comparably high between both groups. However, the extent and distribution of PV reconnections was different in many aspects, indicating more stable atrial lesions after CB PVI compared with PVAC technology.

Paroxysmal atrial fibrillation recurrence after redo procedure-ablation modality impact

BACKGROUND

Atrial fibrillation recurrence (AFR) is common after pulmonary vein isolation (PVI), and the rate does not differ between radiofrequency (RF) and cryoballoon (CB) ablation. The aim of this study was to assess the impact of the ablation modality used at the index PVI on the outcome after redo PVI in patients with paroxysmal AF.

METHODS

In this prospective, single-center, non-randomized study, consecutive patients with paroxysmal AF who have undergone the index PVI with either RF ablation (RF group) or 2nd-generation CB (CB group) were included. The primary endpoint was freedom from recurrence of atrial arrhythmia lasting > 30 s.

RESULTS

A total of 105 patients undergoing redo PVI for paroxysmal AF were included (median age 61 years; 24% female; left ventricular ejection fraction (LVEF) 57 ± 8%; left atrial volume index (LAVI) 34 ± 11 mm). Index PVI was done either with focal RF (n = 81) or with CB (n = 24) and redo PVI only with focal RF. Total procedure time (139 vs. 113 min, p = 0.10) and RF delivery time (1017 vs. 870 s, p = 0.33) of the redo PVI were not significantly different. After a median follow-up of 371 (185-470) days, there were no differences between the RF and CB groups regarding the AFR rate after the second PVI (24 vs. 23%, p = 0.89). The Kaplan-Meier analysis showed no difference between the groups regarding AFR freedom time (p = 0.81). In multivariable logistic regression, only coronary artery disease was identified as an independent long-term predictor of AFR (OR 4.15, 95% CI 1.17-14.71, p = 0.027).

CONCLUSIONS

The ablation modality used at the index PVI has no impact on long-term outcome after redo PVI in patients with paroxysmal AF.

Ablation of persistent atrial fibrillation: Challenges and solutions

Catheter ablation is commonly used for treatment of persistent atrial fibrillation (AF). Pulmonary vein isolation (PVI) is still the cornerstone for the procedure, however, outcomes are consistently lower compared to paroxysmal AF. It is hypothesized that it could be due to lack of durable lesions or the presence of non-PV targets that remain after PVI. Numerous advances in ablation catheter technologies and mapping systems may potentially achieve lower recurrence rates in the future. Ongoing research is required to discover the best technique for persistent AF ablation. The purpose of this review is to describe the new, developing technologies that may improve the outcome of this procedure in the persistent AF population.

Atrial Fibrillation Ablation with Multipolar Phased-Radiofrequency Catheter: The Learning Curve Effect for Procedural Parameters, but not for the Long-Term Outcome

BACKGROUND

Pulmonary vein isolation (PVI) is a routine treatment in atrial fibrillation (AF). Single-shot techniques were introduced to simplify the procedure. We analyzed time-dependent changes in procedural parameters, acute success, complication rates, and long-term outcomes during our initial experience with multipolar phased-radiofrequency (RF) ablation. Methods and Results: The first 126 consecutive patients (98 male; age: 58.8 ± 8.7 years) who underwent PVI with phased-RF ablation at our center were included in the study. Procedural parameters, complication rate, acute success and 12-month efficacy were compared in the first, second and third group of 42 consecutive patients. In all patients, 516/526 PVs were effectively isolated (98.1%), with no differences between the tierces (p = 0.67). Procedure (169.8 vs. 132.9 vs. 105.8 min, p < 0.0001), fluoroscopy (32.9 vs. 24.3 vs. 14.1 min, p < 0.0001) and left atrial dwell (83.0 vs. 61.9 vs. 51.4 min, p < 0.0001) times were significantly reduced with experience in tierces 1-3, respectively. In the 12-month follow-up, 60.3% of patients were arrhythmia-free with no differences between the tierces (p = 0.88). In multivariate analysis, the relapse in the blanking period (p < 0.0001), time from AF diagnosis (p = 0.004) and left atrial diameter (p = 0.012) were the only independent predictors of AF recurrence.

CONCLUSIONS

The learning curve effect was demonstrated in procedural parameters, but not in the complication rate nor the long-term success of PVI with phased-RF technique. The relapse in the blanking period was the strongest predictor of treatment failure in long-time observation.

Pulmonary vein reconnection following cryo-ablation: Mind the "Gap" in the carinae and the left atrial appendage ridge

Pulmonary vein (PV) isolation (PVI) remains cornerstone to ablation of atrial fibrillation (AF). For effective and durable PVI and thus fewer AF recurrences, lesion gaps in transmurality and contiguity responsible for PV reconnection (PVR) could only be addressed when one is cognizant of the potential location and sites where these lesion characteristics may be more prevalent and responsible for PVR. In the case of RF ablation, newer technologies incorporating contact force, time and power with automated monitoring of lesion formation, paying attention to difficult areas (carinae, left superior PV-LAA ridge, right inferior PV) and measuring inter-lesion distance may provide the tools to reduce PVR. On the other hand, the improved thermodynamic characteristics of the latest generation of cryoballloons and operator dexterity to achieve better PV occlusion, may be crucial determinants towards the direction of reduced PVR. Whether newer visualization tools, more vigilant testing during the index ablation procedure in these particular regions, prolonging or adding cryothermic applications, waiting longer to test for entrance and exit block, and/or use of provocative drug testing (isoproterenol/adenosine challenge) might help prevent future PVRs awaits further studies.

Silent cerebral infarcts following pulmonary vein isolation with different atrial fibrillation ablation techniques - incidence and risk factors

Introduction

Silent cerebral infarcts (SCIs) detected by diffusion-weighted magnetic resonance (DW-MRI) following atrial fibrillation (AF) ablation have been reported, with the incidence of 1-38%. We aimed to compare the incidence of SCIs following AF ablation with four different technologies and analyze the risk factors.

Material and methods

A total of 104 patients (mean age: 59.9 ±9.5 years, 68 males) with symptomatic AF, referred for ablation, were included in the study. The AF ablation was performed with irrigated radiofrequency point-by-point technique (RF group) in 24 patients, and with 3 different single-shot techniques: phased-RF (PVAC) in 46, second-generation cryoballoon (CB) in 24 and irrigated multipolar RF catheter (nMARQ) in 10 patients. In all patients DW-MRI was performed pre- and post-procedurally to evaluate the incidence of SCIs. Procedural parameters, complication rate and post-procedural SCI incidence were compared between the groups.

Results

Procedure (167.1 vs. 110.5 vs. 106.0 vs. 141.5 min, p < 0.001), fluoroscopy (22.7 vs. 15.9 vs. 16.3 vs. 15.3 min, p = 0.048) and LA dwell (101.5 vs. 53.9 vs. 56.0 vs. 97.0 min, p < 0.001) times compared respectively between RF, PVAC, CB and nMARQ groups were significantly shorter with single-shot techniques. The number of new-onset SCIs was 4/24 (16.7%) in RF, 7/46 (15.2%) in PVAC, 1/24 (4.2%) in CB and 1/10 (10%) in the nMARQ group. Univariate analysis identified procedure duration (p = 0.02), lower LV ejection fraction (p = 0.03), persistent form of arrhythmia (p = 0.007) and intraprocedural cardioversion (p = 0.002) as risk factors of new-onset SCIs.

Conclusions

Silent cerebral infarcts can be detected following AF ablation regardless of the technology used. Prolonged procedure time, lower ejection fraction, persistent form of arrhythmia and intraprocedural cardioversion increase the risk of SCIs.