Mechanism, underlying substrate and predictors of atrial tachycardia following atrial fibrillation ablation using the second-generation cryoballoon

Pulmonary vein reconnection and repeat ablation characteristics following cryoballoon-compared to radiofrequency-based pulmonary vein isolation

BACKGROUND

Despite advances in efficacy and safety of pulmonary vein isolation (PVI), atrial fibrillation (AF) recurrence after PVI remains common. PV-reconnection is the main finding during repeat PVI procedures performed to treat recurrent AF.

OBJECTIVE

To analyze pulmonary vein (PV) reconnection patterns during repeat ablation procedures in a large cohort of consecutive patients undergoing radio frequency or cryoballoon-based PVI.

METHODS

Retrospective analysis of PV-reconnection patterns and analysis of re-ablation strategies in consecutive index RF- and CB-based PVI and their respective re-ablation procedures during concomitant usage of both energy sources at a single high-volume center in Germany.

RESULTS

A total of 610 first (06/2015-10/2022) and 133 s (01/2016-11/2022) repeat ablation procedures after 363 (60%) RF- and 247 (40%) CB-based index PVIs between 01/2015 and 12/2021 were analyzed. PV-reconnection was found in 509/610 (83%) patients at first and 74/133 (56%) patients at second repeat procedure. 465 of 968 (48%) initially via CB isolated PVs were reconnected at first re-ablation but 796 of 1422 initially RF-isolated PV (56%) were reconnected (OR: 0.73 [95% CI: 0.62-0.86]; p < .001). This was driven by fewer reconnections of the left PVs (LSPV: OR: 0.60 [95% CI: 0.42-0.86]; p = .005 and LSPV: 0.67 [0.47-0.95]; p = .026). PV-reconnection was more likely after longer, RF-based index PVI and in older females. Repeat procedures were shorter after CB-compared to after RF-PVI.

CONCLUSIONS

Reconnection remains the most common reason for repeat AF ablation procedures after PVI. Our data suggest to preferentially use of the cryoballoon during index PVI, especially in older women.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society (HRS), the Asia Pacific HRS, and the Latin American HRS.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society .

Atrial tachycardia occurring after a prior atrial fibrillation ablation procedure: Does non-inducibility matter?

Recurrent atrial tachycardia (AT) is a common phenomenon after catheter ablation for AF, particularly in the setting of additional substrate ablation, with many studies demonstrating gap-related macro re-entrant AT (predominantly mitral and roof dependent) to be the dominant mechanism. Although multiple inducible ATs after ablation of the clinical AT are commonly described at repeat procedures, the optimal ablation strategy, and procedural endpoints are unclear in this setting. A recent randomized study addressing the question of non-inducibility as a procedural endpoint demonstrated no additional benefits to the ablation of all induced, non-clinical ATs, but it was limited by small numbers and high rates of non-inducibility. Nevertheless, once ablation of the clinical AT has been successfully performed, ensuring durable linear block and PV isolation may be sufficient for the prevention of further AT. Durable linear block, particularly at the mitral isthmus, is difficult to achieve but may be facilitated by the real-time evaluation of lesion quality and contiguity and the novel technique of vein of Marshall ethanol infusion. Large-scale, randomized trials are needed, nonetheless, to fully assess the optimal ablation strategy in the setting of recurrent AT post-AF ablation.

Validation of a multipolar pulsed-field ablation catheter for endpoint assessment in pulmonary vein isolation procedures

AIMS

To validate the performance of a multipolar pulsed-field ablation (PFA) catheter compared to a standard pentaspline 3D-mapping catheter for endpoint assessment of pulmonary vein isolation (PVI). PFA for PVI using single-shot devices combines the benefits of high procedural efficacy and safety. A newly available multipolar PFA catheter allows real-time recording of pulmonary vein (PV) signals during PVI.

METHODS AND RESULTS

Patients undergoing first PVI using PFA with the standard ablation protocol (eight applications per PV) were studied. Entrance and exit block (10 V/2 ms) were assessed using the PFA catheter. Subsequently, a high-density 3D electroanatomical bipolar voltage map (3D-EAM) was constructed using a standard pentaspline 3D-mapping catheter. Additional PFA applications were delivered only after confirmation of residual PV connection by 3D-EAM. In 56 patients, 213 PVs were targeted for ablation. Acute PVI was achieved in 100% of PVs: in 199/213 (93%) PVs with the standard ablation protocol alone and in the remaining 14 PVs after additional PFA applications. The accuracy of PV assessment with the PFA catheter after the standard ablation protocol was 91% (194/213 veins). In 5/213 (2.3%) PVs, the PFA catheter incorrectly indicated PV-isolation. In 14/213 (6.6%), the PFA catheter incorrectly indicated residual PV-conduction due to high-output pace-capture. Lowering the output to 5 V/1 ms reduced this observation to 0.9% (2/213) and increased the overall accuracy to 97% (206/213).

CONCLUSION

A novel multipolar PFA catheter allows reliable endpoint assessment for PVI. Due to its design, far-field sensing and high-output pace-capture can occur. Lowering the pacing output increases the accuracy from 91 to 97%.

Catheter Ablation for Atrial Fibrillation in Patients ≤30 Years of Age

Pulmonary vein (PV) automaticity is an established trigger for paroxysmal atrial fibrillation (PAF), making PV isolation (PVI) the cornerstone of catheter ablation. However, data on triggers for atrial fibrillation (AF) and catheter ablation strategy in very young patients aged <30 years are sparse. A total of 51 young patients (mean age 24.0 ± 4.2 years, 78.4% men) with drug-refractory PAF underwent electrophysiology (EP) study and ablation at 5 EP centers. None of the patients had structural heart disease or family history of AF. EP study induced supraventricular tachycardia (SVT) in 12 patients (n = 12, 23.5%): concealed accessory pathway mediated orthodromic atrioventricular reentrant tachycardia in 3 patients, typical atrioventricular nodal reentrant tachycardia in 6 patients, left superior PV tachycardia in 1 patient, left atrial appendage tachycardia in 1 patient, and typical atrial flutter in 1 patient. In patients with induced SVTs, SVT ablation without PVI was performed as an index procedure, except for the patient with atrial flutter who received cavotricuspid isthmus ablation in addition to PVI. Remaining patients underwent radiofrequency (n = 15, 29.4%) or second-generation cryoballoon-based PVI (n = 24, 47%). There were no major complications related to ablation procedures. Follow-up was based on outpatient visits including 24-hour Holter-electrocardiogram at 3, 6, and 12 months after ablation, or additional Holter-electrocardiogram was ordered in case of symptoms suggesting recurrence. Recurrence was defined as any atrial tachyarrhythmia (ATA) episode >30 seconds after a 3-month blanking period. A total of 2 patients with atrioventricular nodal reentrant tachycardia, 1 with left atrial appendage tachycardia, experienced AF recurrence within the first 3 months and received PVI. After the 3-month blanking period, during a median follow-up of 17.0 ± 10.1 months, 44 of 51 patients (86.2%) were free of ATA recurrence. In the PVI group, 33 of 39 patients (84.6%) experienced no ATA recurrence. In conclusion, SVT substrate is identified in around a quarter of young adult patients with history of AF, and targeted ablation without PVI may be sufficient in the majority of these patients. PVI is needed in the majority and is safe and effective in this population.

The Incidence, Electrophysiological Characteristics and Ablation Outcome of Left Atrial Tachycardias after Pulmonary Vein Isolation Using Three Different Ablation Technologies

Background: Left atrial tachycardias (LAT) are a well-known outcome of pulmonary vein isolation (PVI). Few data are available on whether the catheter used to perform PVI influences the incidence, as well as the characteristics of post PVI LAT. We present data on LAT following PVI by the following three ablation technologies: (1) phased multi-electrode radiofrequency catheter (PVAC), (2) irrigated single-tip catheter (iRF), and (3) cryoballoon ablation. Methods: Using a prospectively designed single-center database, we analyzed 650 patients (300 iRF, 150 PVAC, and 200 cryoballoon) with paroxysmal (n = 401) and persistent atrial fibrillation (AF), who underwent their first PVI at our center. Results: The three populations were comparable in their baseline characteristics; however, the cryoballoon group comprised a higher percentage of patients with persistent AF (p = 0.05). The LAT rates were 3.7% in the iRF group (mean follow-up 22 ± 14 months), 0.7% in the PVAC group (mean follow-up 21 ± 14 months), and 4% in the cryoballoon group (mean follow-up 15 ± 8 months). The predominant mechanism of LAT was macro-reentrant tachycardia. Reconnection of at least one pulmonary vein was observed in 87% of the patients who underwent 3D mapping. No predictors for LAT occurrence were identified. Conclusion: The occurrence of LAT post PVI is rare; the predominant mechanism was macro-reentrant tachycardia. Reconnection of at least one pulmonary vein was observed in nearly all the LAT patients. In our retrospective analysis, the lowest rate of LAT was observed with the PVAC. No predictors for LAT occurrence were identified.

Early arrhythmia recurrence after cryoballoon ablation in atrial fibrillation: a systematic review and meta-analysis

BACKGROUND

Early arrhythmia recurrence within the three-month blanking period is a common event that historically has been attributed to reversible phenomena. While its' mechanistic links remain obscure, accumulating evidence support the argument of shortening the blanking period. We aimed to elucidate the association between early and late arrhythmia recurrence after atrial fibrillation cryoablation.

METHODS

The MEDLINE database, ClinicalTrials.gov, medRxiv and Cochrane Library were searched for studies evaluating early and late arrhythmia recurrence rates in patients undergoing cryoablation for AF. Data were pooled by meta-analysis using a random-effects model. The primary endpoint was late arrhythmia recurrence.

RESULTS

Early arrhythmia recurrence was found predictive of decreased arrhythmia-free survival after evaluating 3975 patients with paroxysmal or persistent atrial fibrillation who underwent cryoablation (OR: 5.31; 95% CI: 3.75-7.51). This pattern remained unchanged after sub-analyzing atrial fibrillation type (paroxysmal; OR: 7.16; 95% CI: 4.40-11.65 and persistent; OR: 7.63; 95% CI: 3.62-16.07) as well as cryoablation catheter generation (first generation; OR: 5.15, 95% CI: 2.39-11.11 and advanced generation; OR: 5.83, 95% CI: 3.68-9.23). Studies permitting anti-arrhythmic drug utilization during blanking period or examining early recurrence as a secondary outcome were found to be a significant source of statistical heterogeneity.

CONCLUSION

Our findings suggest that early arrhythmia recurrence is predictive of late outcomes after cryoablation for atrial fibrillation. Identifying which patients deserve earlier re-intervention is an open research avenue. This article is protected by copyright. All rights reserved.

Cryoballoon ablation of the left atrial posterior wall reduces recurrence of persistent atrial fibrillation in patients with non-paroxysmal atrial fibrillation

BACKGROUND

This study aimed to clarify the clinical outcomes of cryoballoon ablation of the left atrial (LA) posterior wall (LAPW), including the LA roof, in patients with non-paroxysmal atrial fibrillation (AF).

METHODS

We analyzed the outcomes of 284 patients with non-paroxysmal AF, of whom 210 underwent the cryoballoon ablation of the LAPW, including the LA roof, in addition to pulmonary vein isolation with a cryoballoon.

RESULTS

Complete conduction block at the LA roof was obtained in 95.7% (201/210) of patients, and LAPW was isolated in 83.3% (130/156) of patients. Over 372 (range, 208-477) days of follow-up, atrial arrhythmia recurrence was observed in 84 (29.6%) patients, and atrial tachycardia (AT) recurrence accounted for 27.4% of cases. The prevalence of LA roof cryoballoon ablation was significantly higher in patients without recurrence than in those with recurrence (78.6% vs. 63.1%, respectively; p = .01), especially those with persistent AF recurrence (77.0% vs. 55.0%, p = .01). No significant difference was found in the prevalence of AT recurrence between patients who had undergone additional LAPW ablation and those who had not. Durable LA roof lesions were confirmed in 29 (72.5%) of 40 patients who underwent redo ablation.

CONCLUSIONS

Cryoballoon ablation of the LAPW leads to a sufficient acute success rate of complete conduction block and durable lesions of the LA roof without increasing AT recurrence risk. The prevalence of persistent AF recurrence decreases after additional cryoballoon ablation of the LAPW in patients with non-paroxysmal AF.

Experience and procedural efficacy of pulmonary vein isolation using the fourth and second generation cryoballoon: The shorter, the better?

BACKGROUND

The second-generation cryoballoon (CB2) provides effective and durable pulmonary vein isolation (PVI) associated with encouraging clinical outcome. The novel fourth-generation cryoballoon (CB4) incorporates a 40% shorter distal tip. This design change may translate into an increased rate of PVI real-time signal recording, facilitating an individualized ablation strategy using the time to effect (TTE).

METHODS AND RESULTS

Three hundred consecutive patients with paroxysmal or persistent atrial fibrillation were prospectively enrolled. The first 150 consecutive patients underwent CB2 based PVI (CB2 group) and the last 150 consecutive patients were treated with the CB4 (CB4 group). A total of 594/594 (100%, CB4) and 589/594 (99.2%, CB2) pulmonary veins (PVs) were successfully isolated utilizing the CB4 and CB2, respectively (p = .283). The real-time PVI visualization rate was 47% (CB4) and 39% (CB2; p = .005) and the mean freeze cycle duration 200 ± 90 s (CB4) and 228 ± 110 s (CB2; p < .001), respectively. The total procedure time did not differ between the groups (CB4: 64 ± 32 min) and (CB2: 62 ± 29 min, p = .370). No differences in periprocedural complications were detected.

CONCLUSIONS

A higher rate of real-time electrical PV recordings are seen using the CB4 as compared to CB2, which may facilitate an individualized ablation strategy using the TTE.

Redefining the Blanking Period by a Long-Term Follow-Up after Atrial Fibrillation Ablation Using Second-Generation Cryoballoon

On the basis of radiofrequency ablation of atrial fibrillation (AF), some studies suggested that early recurrences of atrial tachyarrhythmia (ERATs) were associated with late AF recurrence (LAFR), and some also suspected and challenged the current recommended 90 day blanking period. We aim to evaluate the impact of ERAT on long-term success and to determine the optimum blanking period after AF ablation using second-generation cryoballoon (sg-CB). From August 2016 to October 2018, 369 consecutive patients who successfully underwent initial AF ablation using sg-CB at the Fuwai Hospital were finally enrolled. All patients were followed up no less than 12 months. Receiver operating characteristic curve analysis was used to determine the optimum blanking period after AF ablation. There were 62 (16.8%) who experienced ERAT. After a median follow-up of 615 days, 74.5% were free of LAFR after the 90 day blanking period. Incidence of freedom from LAFR during the long-term follow-up was markedly lower in patients with ERAT than in those without ERAT (27.4% versus 84.0%; log-rank P < 0.001). Furthermore, only ERAT (HR 8.579; 95% CI 5.604-13.133; P < 0.001) was significantly associated with an increased risk of LAFR after adjusting for other factors. The optimum cut-off time point for the blanking period was 21.5 days (sensitivity: 71.1%, specificity: 94.1%). In conclusion, ERAT was an independent predictor of LAFR after AF ablation using sg-CB. Based on our findings, blanking period was advised to be shorten to 21.5 days or about 3 weeks instead of 90 days after CB ablation.

Atrial Tachycardias After Atrial Fibrillation Ablation: How to Manage?

With catheter ablation becoming effective for non-pharmacological management of AF, many cases of atrial tachycardia (AT) after AF ablation have been reported in the past decade. These arrhythmias are often symptomatic and respond poorly to medical therapy. Post-AF-ablation ATs can be classified into the following three categories: focal, macroreentrant and microreentrant ATs. Mapping these ATs is challenging because of atrial remodelling and its complex mechanisms, such as double ATs and multiple-loop ATs. High-density mapping can achieve precise identification of the circuits and critical isthmuses of ATs and improve the efficacy of catheter ablation. The purpose of this article is to review the mechanisms, mapping and ablation strategy, and outcome of ATs after AF ablation.

Comparative Study of Cryoballoon versus Radiofrequency for Pulmonary Vein Isolation when Combined with vein of Marshall Ethanol Infusion for Paroxysmal Atrial Fibrillation

Introduction

Ethanol infusion (EI) in the vein of Marshall (VOM) has multifactorial effects that could be synergistic to pulmonary vein isolation (PVI) in ablation of atrial fibrillation (AF). The efficacy of radiofrequency (RF) versus cryoablation when combined with a VOM-EI has never been investigated. The aim of this study is to evaluate outcome differences of AF ablation using RF versus cryoablation when combined with a VOM-EI.

Materials and Methods

Consecutive patients (n=132) underwent catheter ablation of paroxysmal AF with either RF or cryoballoon (CB) for PVI combined with VOM-EI. Bi-directional conduction block at the mitral isthmus was attempted. The end-point was the freedom from any atrial arrhythmias documented after a blanking period of 90 days after the procedure.

Results

Kaplan-Meier estimates of the arrhythmia-free survival after 1 year were 63.8 (RF + VOM), and 82.7 % (CB + VOM), respectively. Comparison between CB + VOM versus RF + VOM reached a significance (p=0.0292). The periprocedural complication rate was comparable in both groups (5.0 % RF, 5.8 % CB; p=0.14) with a significant difference in the incidence of phrenic nerve palsy (0 % RF, 2.0 % CB; p<0.05).

Conclusions

PVI with a CB had an increased freedom from AF recurrence compared to RF combined with VOM-EI. The present results suggest a potential additive effect of a VOM-EI to CB application.