Cryoballoon ablation of pulmonary veins for persistent atrial fibrillation: Results from the multicenter STOP Persistent AF trial

Subjective identification and ablation of drivers improves rhythm control in patients with persistent atrial fibrillation. The CHAOS-AF study

INTRODUCTION AND OBJECTIVES

The optimal approach for persistent atrial fibrillation (AF) ablation remains unknown. In patients with persistent AF, we compared an ablation strategy based on pulmonary vein isolation (PVI) plus ablation of drivers (PVI+D), with a conventional PVI-only approach performed in a 1:1 propensity score-matched cohort.

METHODS

Drivers were subjectively identified using conventional high-density mapping catheters (IntellaMap ORION, PentaRay NAV or Advisor HD Grid), without dedicated software, as fractionated continuous or quasicontinuous electrograms on 1 to 2 adjacent bipoles, which were ablated first; and as sites with spatiotemporal dispersion (the entire cycle length comprised within the mapping catheter) plus noncontinuous fractionation, which were only targeted in patients without fractionated continuous electrograms, or without AF conversion after ablation of fractionated continuous electrograms. Ablation included PVI plus focal or linear ablation targeting drivers.

RESULTS

A total of 50 patients were included in each group (61±10 years, 25% women). Fractionated continuous electrograms were found and ablated in 21 patients from the PVI+D group (42%), leading to AF conversion in 7 patients. In the remaining 43 patients, 143 sites with spatiotemporal dispersion plus noncontinuous fractionation were targeted. Globally, AF conversion was achieved in 21 patients (42%). The PVI+D group showed lower atrial arrhythmia recurrences at 1 year of follow-up (30.6% vs 48%; P=.048) and at the last follow-up (46% vs 72%; P=.013), and less progression to permanent AF (10% vs 40%; P=.001).

CONCLUSIONS

Subjective identification and ablation of drivers, added to PVI, increased 1-year freedom from atrial arrhythmia and decreased long-term recurrences and progression to permanent AF.

Catheter ablation for atrial fibrillation in elderly patients: an updated meta-analysis of comparative studies

BACKGROUND

Age is a relevant risk factor for the development of atrial fibrillation (AF) and is associated with increased recurrence rates in the setting of rhythm-control. Catheter ablation is increasingly advocated in elderly despite conflicting data regarding its efficacy and safety in this patient cohort. Therefore, we aimed to analyze currently available evidence regarding catheter ablation for AF in patients ≥75 years compared to younger patients.

METHODS

We performed a systematic literature search and meta-analysis on efficacy and safety of catheter ablation in patients ≥75 years with AF. Primary efficacy and safety endpoints were: first recurrence of atrial arrhythmia following first-time ablation and occurrence of death, stroke, or any procedure-related complication. Secondary outcomes included procedure and fluoroscopy time.

RESULTS

We identified 301 potentially relevant studies of which 39 underwent detailed analysis. A total of 19 studies (MINORS score ≥13) reporting on 108,419 patients (101,844 <75 years, 6,575 ≥75 years) undergoing first-time catheter ablation for AF were included. Risk of arrhythmia recurrence following catheter ablation (39% vs. 32%; RR [95% CI] 1.24 [1.09-1.41]; P=0.001) and occurrence of safety endpoints (10.8% vs. 8.5%; RR [95% CI] 1.64 [1.53-1.76], P<0.00001) were significantly higher in patients ≥ 75 years compared to younger patients. There was no difference concerning procedure (P=0.33) or fluoroscopy time (P=0.91) between younger and elderly patients.

CONCLUSION

In patients ≥75 years of age catheter ablation for AF has higher risk of arrhythmia recurrence and is associated with an increased risk of procedure-related complications and safety endpoint occurrence compared to younger patients.

Failure of intravenous nifekalant cardioversion as an independent predictor for persistent atrial fibrillation recurrence after catheter ablation

AIMS

Nifekalant is a class III antiarrhythmic drug that exerts antiarrhythmic effects by inhibiting rapid rectifying potassium channels and extending the effective refractory period of cardiomyocytes. It has a high success rate in converting atrial fibrillation (AF) to sinus rhythm. Whether the failure of intravenous nifekalant cardioversion is an independent predictor for persistent AF recurrence after catheter ablation has not been reported.

METHODS

A total of 92 patients with drug-refractory persistent AF were retrospectively enrolled. After all ablations, intravenous nifekalant was administrated. Patients were assigned to the success group (group 1) and failure group (group 2) based on nifekalant cardioversion results and followed for 12 months to note any episode of atrial arrhythmia recurrence.

RESULTS

Each group included 46 patients. After 12 months of follow-up, nine (19.6%) patients from group 1 and 23 (50.0%) patients from group 2 had a recurrence of atrial tachyarrhythmia (P = 0.002). AF duration and type 2 diabetes were strongly associated with failure of intravenous nifekalant cardioversion. Univariable Cox proportional hazard regression showed that failure of intravenous nifekalant cardioversion, AF duration, and type 2 diabetes were potential risk factors. Multivariable Cox proportional hazard regression showed that failure of nifekalant cardioversion was statistically associated with AF recurrence (adjusted RR = 2.257, 95% CI: 1.006-5.066, P = 0.048). Failure of intravenous nifekalant cardioversion could bring a positive effect on the prognostic differentiation when added into the multivariable model (0.767 ± 0.042 vs. 0.774 ± 0.045, P = 0.025).

CONCLUSION

Failure of nifekalant cardioversion is an independent predictor for persistent AF recurrence after catheter ablation.

Dual-energy lattice-tip ablation system for persistent atrial fibrillation: a randomized trial

Clinical outcomes of catheter ablation for atrial fibrillation (AF) are suboptimal due, in part, to challenges in achieving durable lesions. Although focal point-by-point ablation allows for the creation of any required lesion set, this strategy necessitates the generation of contiguous lesions without gaps. A large-tip catheter, capable of creating wide-footprint ablation lesions, may increase ablation effectiveness and efficiency. In a randomized, single-blind, non-inferiority trial, 420 patients with persistent AF underwent ablation using a large-tip catheter with dual pulsed field and radiofrequency energies versus ablation using a conventional radiofrequency ablation system. The primary composite effectiveness endpoint was evaluated through 1 year and included freedom from acute procedural failure and repeat ablation at any time, plus arrhythmia recurrence, drug initiation or escalation or cardioversion after a 3-month blanking period. The primary safety endpoint was freedom from a composite of serious procedure-related or device-related adverse events. The primary effectiveness endpoint was observed for 73.8% and 65.8% of patients in the investigational and control arms, respectively (P < 0.0001 for non-inferiority). Major procedural or device-related complications occurred in three patients in the investigational arm and in two patients in the control arm (P < 0.0001 for non-inferiority). In a secondary analysis, procedural times were shorter in the investigational arm as compared to the control arm (P < 0.0001). These results demonstrate non-inferior safety and effectiveness of the dual-energy catheter for the treatment of persistent AF. Future large-scale studies are needed to gather real-world evidence on the impact of the focal dual-energy lattice catheter on the broader population of patients with AF. ClinicalTrials.gov identifier: NCT05120193 .

Elevated liver fibrosis-4 index predicts recurrence after catheter ablation for atrial fibrillation in patients with heart failure

BACKGROUND

The fibrosis-4 (FIB-4) index is a noninvasive scoring system that is used to assess the progression of liver fibrosis. This study aimed to assess whether the FIB-4 index is associated with recurrent atrial fibrillation (AF) after catheter ablation in patients with and without heart failure (HF).

METHODS

We included 1,184 patients who underwent initial AF catheter ablation between 2016 and 2021. The patients were classified into low-risk (< 1.3), intermediate-risk (1.3-2.67), and high-risk (> 2.67) groups based on their FIB-4 indices at baseline. The patients were divided into HF (n = 552) and non-HF groups (n = 632); the HF group was further divided into paroxysmal AF (PAF) and non-PAF groups. AF recurrence after catheter ablation was then compared among the groups.

RESULTS

In the non-HF group, no significant differences in recurrence after ablation were observed between the low-(n = 219), intermediate-(n = 364), and high-risk (n = 49) groups. In contrast, in the HF group, the intermediate-(n = 341) and high-risk (n = 112) groups had significantly higher recurrence rates than the low-risk group (n = 99) (log-rank test, p = 0.005). This association remained significant after multivariate analysis (hazard ratio [HR]:1.374; p = 0.027). The FIB-4 index increased incrementally as the brain natriuretic peptide levels and severity of tricuspid regurgitation increased. The FIB-4 index was an independent predictor of recurrence in the non-PAF HF group (HR:1.498; p = 0.007) but not in the PAF group.

CONCLUSIONS

The FIB-4 index may be a useful predictor of AF recurrence after catheter ablation in patients with HF, particularly in those with non-PAF.

Pulmonary Vein Isolation or Pace and Ablate in Elderly Patients With Persistent Atrial Fibrillation (ABLATE Versus PACE)-Rationale, Methods, and Design

Age is a major risk-factor for atrial fibrillation (AF) and associated hospitalisations. With increasing emphasis on rhythm control, pulmonary vein isolation (PVI) is often suggested, even to elderly patients (≥ 75 years of age). Efficacy of PVI aiming at rhythm control is limited in persistent AF. Pacemaker implantation with atrioventricular node (AVN) ablation may represent a reasonable alternative, with the aim of controlling symptoms and improving quality of life in elderly patients. In this investigator-initiated, randomised, multicentre trial, we test the hypothesis that pacemaker implantation and AVN ablation provides superior symptom control over PVI in elderly patients with symptomatic persistent AF, without any increase in adverse event profile. In the ABLATE Versus PACE (NCT04906668) prospective open-label superiority trial, 196 elderly patients with normal ejection fraction and symptomatic persistent AF despite guideline-indicated medical therapy will be randomised to either cryoballoon PVI (ABLATE) or dual-chamber pacemaker implantation with subsequent AVN ablation (PACE), and followed for a minimum of 12 months. The primary efficacy outcome is a composite end point of rehospitalisation for atrial arrhythmia or cardiac decompensation/heart failure, (outpatient) electrical cardioversion, or upgrade to cardiac resynchronisation therapy owing to worsening of left ventricular ejection fraction to ≤ 35%. Secondary end points include death from any cause, stroke, quality of life, and procedure-related complications. Sample size is designed to achieve 80% power for the primary end point (2-tailed alpha of 5%). ABLATE Versus PACE will determine whether pacemaker implantation and AVN ablation can improve symptom-control in elderly patients with persistent AF over PVI without increasing safety end points.

Long-term Outcome of Cryoballoon Ablation in Korean Patients With Atrial Fibrillation: Real-world Experience From the Cryo Global Registry

BACKGROUND AND OBJECTIVES

Atrial fibrillation (AF), the most common atrial arrhythmia (AA), is an increasing healthcare burden in Korea. The objective of this sub-analysis of the Cryo Global Registry was to evaluate long-term efficacy, symptom burden, quality of life (QoL), and healthcare utilization outcomes and factors associated with AA recurrence in Korean patients treated with cryoballoon ablation (CBA).

METHODS

Patients were treated and followed up according to local standard-of-care in 3 Korean hospitals. Kaplan-Meier estimates were used in analyzing (1) efficacy defined as freedom from ≥30 second recurrence of AA at 24 months, (2) healthcare utilization, and (3) predictors of 24-month AA recurrence. Patient-reported QoL (using European Quality of Life-5 Dimensions-3 Levels) and predefined AF-related symptoms were assessed at baseline and 24-month follow-up.

RESULTS

Efficacy was 71.9% in paroxysmal AF (PAF) and 49.3% in persistent AF (PsAF) patients (p<0.01). A larger left atrial diameter (LAD), an increased time from AF diagnosis to CBA, and PsAF were independent predictors of AA recurrence. The percentage of patients with no AF symptoms significantly increased from baseline (24.5%) to 24-month (89.5%) follow-up (p<0.01). Improvement in QoL from baseline to 24 months was not statistically different between AF cohorts. PAF patients experienced greater freedom from repeat ablations (93.9% vs. 81.4%) and cardiovascular hospitalizations (91.3% vs. 72.5%, p<0.001 for both).

CONCLUSIONS

In alignment with global outcomes, CBA is an effective treatment for AF in the Korean population, with patients possessing a large LAD and not receiving ablation soon after diagnosis being the most at risk for AA recurrence.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02752737.

Chinese guidelines for the diagnosis and management of atrial fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, significantly impacting patients' quality of life and increasing the risk of death, stroke, heart failure, and dementia. Over the past two decades, there have been significant breakthroughs in AF risk prediction and screening, stroke prevention, rhythm control, catheter ablation, and integrated management. During this period, the scale, quality, and experience of AF management in China have greatly improved, providing a solid foundation for the development of the guidelines for the diagnosis and management of AF. To further promote standardized AF management, and apply new technologies and concepts to clinical practice timely and fully, the Chinese Society of Cardiology of Chinese Medical Association and the Heart Rhythm Committee of Chinese Society of Biomedical Engineering jointly developed the Chinese Guidelines for the Diagnosis and Management of Atrial Fibrillation. The guidelines comprehensively elaborated on various aspects of AF management and proposed the CHA2DS2‑VASc‑60 stroke risk score based on the characteristics of the Asian AF population. The guidelines also reevaluated the clinical application of AF screening, emphasized the significance of early rhythm control, and highlighted the central role of catheter ablation in rhythm control.

Raise-up technique for the creation of left atrial roof lesion: A useful technique with cryoballoon for persistent atrial fibrillation

INTRODUCTION

Recent studies have reported the efficacy of the cryoballoon (CB)-guided left atrial roof block line (LARB) creation in patients with persistent atrial fibrillation (AF). However, it can be technically challenging to attach the balloon to the left atrial (LA) roof due to its anatomical variations. We designed a new procedure called the "Raise-up Technique," which may facilitate the firm adhesion of the CB to the LA roof during freezing. This study aimed to evaluate the efficacy of the Raise-up technique in LARB creation.

METHODS AND RESULTS

In total, 100 consecutive patients with persistent AF who underwent CB-LARB creation were enrolled. Fifty-seven patients underwent LARB creation using the Raise-up technique (Raise-up group), and the remaining 43 did not use it (control group). The Raise-up technique was performed as follows: An Achieve catheter was inserted as deeply as possible into the upper branch of the right superior pulmonary vein to anchor the CB. The balloon was placed below the targeted site on the LA roof and frozen. When the temperature of the CB reached approximately -10°C and the CB was easier to attach to the LA tissue, the CB was raised and pressed against the LA roof immediately by sheath advancement. Then the balloon could be in firm contact with the target site on the roof. If necessary, additional sheath advancement after sufficient freezing (-20°C to -30°C) was allowed the CB to have more firm and broad contact with the target site. LARB creation without touch-up ablation was achieved in 54 of 57 patients (94.7%) in the Raise-up group and 33 of 43 patients (76.7%) in the control group (p < .05). The lesion size of the LARB in the Raise-up group was significantly larger than that in the control group (15.2 cm2 vs. 12.8 cm2, p < .05). Moreover, the width of the LARB lesion in the Raise-up group was wider than that in the control group (32.0 mm vs. 26.6 mm, p < .05).

CONCLUSION

The Raise-up technique enabled the creation of seamless and thick LARB lesions with a single stroke. In addition, the CB-LARB lesions created using the Raise-up technique tended to be large, resulting in extensive debulking of the LA posterior wall arrhythmia substrates. In CB ablation for persistent AF, the Raise-up technique can be considered one of the key strategies for LARB creation.

Regional variations in patient selection and procedural characteristics for cryoballoon ablation of atrial fibrillation in the cryo global registry

BACKGROUND

Cryoballoon ablation is a well-established anatomical approach for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). Although widely adopted, regional variations in standards of care have not been well characterized.

METHODS

Patients with AF were enrolled in the Cryo Global Registry (NCT02752737) from May 2016 to Sept 2021 at 128 sites in 37 countries and treated with cryoballoon ablation according to local clinical practice. Baseline patient and procedural characteristics were summarized for 8 regions (Central Asia & Russia, East Asia, Europe, Middle East, North America, South Africa, South America, and Southeast Asia). Serious procedure-related adverse events (SAEs) were evaluated in a subset of patients with ≥ 7 days of follow-up.

RESULTS

A total of 3,680 patients undergoing initial PVI for AF were included. Cryoballoon ablation was commonly performed in patients with paroxysmal AF. Mean age ranged from 47 ± 12 years in the Middle East to 64 ± 11 years in East Asia. Mean procedure time was ≤ 95 min in all regions. Average freeze duration ranged from 153 ± 41 s in Southeast Asia to 230 ± 29 s in Central Asia & Russia. Acute procedural success was ≥ 94.7% in all geographies. In 3,126 subjects with ≥ 7 days of follow-up, 122 procedure-related SAEs were reported in 111 patients (3.6%) and remained low in all regions. One procedure-related death was reported during data collection.

CONCLUSIONS

Despite regional variations in patient selection and procedural characteristics, PVI using cryoballoon ablation was performed with high acute success and short procedural times around the world.

CLINICAL TRIAL REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT02752737.

Chinese Guidelines for the Diagnosis and Management of Atrial Fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, significantly impacting patients' quality of life and increasing the risk of death, stroke, heart failure, and dementia. Over the past two decades, there have been significant breakthroughs in AF risk prediction and screening, stroke prevention, rhythm control, catheter ablation, and integrated management. During this period, the scale, quality, and experience of AF management in China have greatly improved, providing a solid foundation for the development of guidelines for the diagnosis and management of AF. To further promote standardized AF management, and apply new technologies and concepts to clinical practice in a timely and comprehensive manner, the Chinese Society of Cardiology of the Chinese Medical Association and the Heart Rhythm Committee of the Chinese Society of Biomedical Engineering have jointly developed the Chinese Guidelines for the Diagnosis and Management of Atrial Fibrillation. The guidelines have comprehensively elaborated on various aspects of AF management and proposed the CHA2DS2-VASc-60 stroke risk score based on the characteristics of AF in the Asian population. The guidelines have also reevaluated the clinical application of AF screening, emphasized the significance of early rhythm control, and highlighted the central role of catheter ablation in rhythm control.

Feasibility of double-blinded, placebo-controlled interventional study for assessing catheter ablation efficacy in persistent atrial fibrillation: Insights from the ORBITA AF feasibility study

BACKGROUND

To date, there are no randomized, double-blinded clinical trials comparing catheter ablation to DC cardioversion (DCCV) with medical therapy in patients with persistent atrial fibrillation (PersAF). Conducting a large-scale trial to address this question presents considerable challenges, including recruitment, blinding, and implementation. We conducted a pilot study to evaluate the feasibility of conducting a definitive placebo-controlled trial.

METHODS

This prospective trial was carried out at Barts Heart Centre, United Kingdom, employing a randomized, double-blinded, placebo-controlled design. Twenty patients with PersAF (duration <2 years) were recruited, representing 10% of the proposed larger trial as determined by a power calculation. The patients were randomized in a 1:1 ratio to receive either PVI ± DCCV (PVI group) or DCCV + Placebo (DCCV group). The primary endpoint of this feasibility study was to evaluate patient blinding. Patients remained unaware of their treatment allocation until end of study.

RESULTS

During the study, 35% of patients experienced recurrence of PersAF prior to completion of 12 months follow-up. Blinding was successfully maintained amongst both patients and medical staff. The DCCV group had a trend to higher recurrence and repeat procedure rate compared to the PVI group (recurrence of PersAF 60% vs 30%; p = .07 and repeat procedure 70% vs 40%; p = .4). The quality of life experienced by individuals in the PVI group showed improvement, as evidenced by enhanced scores on the AF specific questionnaire (AF PROMS) (3 [±4] vs 21 [±8]) and SF-12 mental-component raw score (51.4 [±7] vs 43.24 [±15]) in patients who maintained sinus rhythm at 12 months.

CONCLUSION

This feasibility study establishes the potential for conducting a blinded, placebo-controlled trial to evaluate the efficacy of PVI versus DCCV in patients with PersAF.

Pulmonary vein capture is a predictor for long-term success of stand-alone pulmonary vein isolation with cryoballoon ablation in patients with persistent atrial fibrillation

Background

The mechanisms of AF development and progression are still not completely understood. Despite the relative efficacy of ablation, the risk of AF recurrence is substantial, particularly in patients with persistent AF (perAF). At present we do not have any reliable intra-procedural electrophysiologic predictors of long-term success of AF ablation other than pulmonary vein isolation. We evaluated selected intraprocedural pulmonary vein characteristics that may be helpful in future guidance of persistent AF ablation.

Methods

390 consecutive procedures using cryoballoon for initial AF ablation were divided by clinical presentation (paroxysmal or persistent AF), and by pulmonary vein (PV) response to pacing after completion of ablation (discrete electrogram elicited with pacing-"PV capture" or not-"Control"). Patients were followed (median 20 months) for recurrent atrial arrhythmias as the primary end point of the study.

Results

PV capture was identified in 20.3% and 17.1% and patients with paroxysmal and persistent AF respectively (ns). In patients with persistent AF presence of PV capture was associated with significantly better outcomes compared to patients without PV capture (p < 0.001). In the group "persistent AF and PV capture", an initial strategy of PV isolation and reisolation of the PVs (without additional lesions) for patients with recurrent atrial arrhythmias resulted in 20/23 (87%) patients in sinus rhythm off antiarrhythmic medications at study completion. In patients with paroxysmal AF, PV capture was not associated with outcome benefits. Specific electrophysiologic characteristics of PV (PV capture cycle length: PVCCL) did not have an impact on AF recurrence, although 25% shortening of PVCCL was observed after 60 s periods of pacing at short cycle lengths. No background demographic patient characteristic differences were identified between patients with vs. without PV capture.

Conclusion

The presence of PV capture was associated with better outcomes in patients with persistent AF. PV capture may identify those patients with persistent AF in whom cryoballoon PV isolation alone is sufficient as an initial ablation procedure and as the primary ablation strategy for recurrent AF.

Pulmonary Vein Isolation in Elderly Patients ≥ 75 Years: A Propensity Score-Matched Analysis With Focus on Differences Among Atrial Fibrillation Types

BACKGROUND

Age is a major risk factor for development of atrial fibrillation (AF) and associated with increased recurrence rates in the setting of rhythm control. Current data tend to support catheter ablation in elderly patients, but uncertainties exist regarding efficacy and safety of ablation in elderly patients.

METHODS

This was a prospective single-centre observational study with propensity score matching (PSM) to investigate the influence of age on efficacy and safety of cryoballoon ablation (CBA) stratified by age (< 75 years vs ≥ 75 years) and AF phenotype (paroxysmal vs persistent). Primary efficacy endpoint was recurrence of atrial arrhythmia after a 90-day blanking period. Safety endpoints were death, stroke, or procedure-associated complications.

RESULTS

Consecutive patients (n = 953) underwent CBA for first-time AF ablation. Median follow-up was 18 months. By means of PSM, 268 matches were formed. At 1 year, primary efficacy endpoint occurred in 22.4% of young vs 33.2% of elderly patients, including both AF phenotypes (hazard ratio [HR], 0.65; 95% confidence interval [CI], 0.47-0.90; P = 0.01). AF relapse occurred in 19.7% of young vs 28.5% of elderly patients with paroxysmal (HR, 0.63; 95% CI, 0.40-0.99; P = 0.046) compared with 25.9% (30 of 116, young) vs 38.8% (45 of 116, elderly) patients with persistent AF (HR, 0.62; 95% CI, 0.39-0.97; P = 0.038). No difference was observed regarding the incidence of safety endpoints between young and elderly patients (P = 0.38).

CONCLUSIONS

CBA is associated with higher recurrence rates in elderly (≥ 75 years) than in younger patients, with highest recurrence rates in elderly patients with persistent AF.

Cryoballoon ablation of non-PV triggers in persistent atrial fibrillation

Cryoballoon-based catheter ablation has emerged as an efficacious and safe therapeutic intervention for patients with paroxysmal atrial fibrillation (PAF). PAF is primarily associated with the triggers in the pulmonary vein (PV). However, persistent atrial fibrillation (PeAF) is a complex condition that involves changes in the atrial substrate and the presence of non-PV triggers. Therefore, a comprehensive treatment approach is necessary for patients with PeAF. Utilizing a 3D electroanatomical map, the radiofrequency-based ablation technique adeptly identifies and targets the atrial substrate and non-PV triggers. On the other hand, the cryoballoon-based AF ablation was initially designed for PV isolation. However, its single-shot feature makes it a great choice for electrophysiologists looking to address non-PV triggers. It is possible to target the left atrial appendage (LAA), superior vena cava (SVC), left atrial roof, and posterior wall using the apparatus's unique configuration and ablation abilities. This review focuses on the increasing literature regarding cryoballoon-based methods for non-PV trigger ablation. Specifically, it delves into the technical procedures used to isolate the LAA, SVC, and ablate the left atrial roof and posterior wall.

Long-term efficacy and safety of cryoballoon ablation of atrial fibrillation: A systematic review and meta-analysis

BACKGROUND

This meta-analysis evaluated long-term efficacy and safety of cryoballoon ablation (CB) of atrial fibrillation (AF).

METHODS

PubMed, Cochrane Library, and Web of Science were searched until July 31, 2023, for published works investigating efficacy and safety of CB of AF in which mean/median follow-up time was not less than 36 months. Safety was assessed by adverse events. Efficacy was assessed by AF recurrence, defined as any atrial arrhythmias lasting more than 30 s.

RESULTS

A total of 19 clinical studies were included. After an average of 58.1 months of follow-up, the overall AF recurrence rate was about 37%. The predictors of recurrence were duration of AF (HR 1.00; 95% CI [1.00 ∼ 1.01]), early recurrence of atrial fibrillation (HR 3.96; 95%CI [1.12 ∼ 14.02]), left atrial diameter (HR 1.04; 95%CI [1.02 ∼ 1.06]), and persistent AF (HR1.47; 95% CI [1.19 ∼ 1.82]). In terms of safety, the incidence of transient phrenic paralysis (PNP) was the highest, about 3%; followed by vascular complications (about 2%); pseudoaneurysm, permanent PNP, and all-cause death was (about 1%); and pericardial effusion and stroke / TIA was very low.

CONCLUSION

CB is associated with low rates of severe complications and reasonable success rates.

Pulsed field ablation as a precise approach for cardiac arrhythmia treatment via cardiac microenvironment remodeling

PFA uses short-duration, high-voltage electrical pulses to induce transient or irreversible electroporation on cell membranes, causing cell death. Selective inhibition of chaotic electrical signals in morbid cardiomyocytes significantly aids the treatment of atrial fibrillation, ventricular tachycardia, and other heart arrhythmias. Recent preclinical and clinical studies have only investigated physical changes, such as lesion size and myocardial scar. Compared to radiofrequency ablation and cryoballoon ablation, PFA causes less postoperative myocardial cell fibrosis and inflammatory reaction and does not result in myocardial necrosis or tissue scar formation. However, the regulatory mechanism of cellular stress following PFA treatment remains unknown. This study aimed to analyze the transcriptome of the mouse ventricle after PFA treatment. The animals were subjected to a 225-V electric pulse with a 1.5-mm gap between the positive and negative electrodes. Hearts were harvested at 3, 6, 12, 24 h, and 2, 5 days for myocardial zymogram testing. PFA-treated ventricular regions were selected for single-nucleus sequencing. We discovered that PFA remodeled the cardiac microenvironment as a whole. Further, we discussed the possible stress response and wound-healing mechanism in non-targeted cells. In conclusion, PFA allowed effective and selective ventricular myocardium ablation with controllable inflammation.

Atrial fibrillation cryoablation is an effective day case treatment: the UK PolarX vs. Arctic Front Advance experience

AIMS

Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation for atrial fibrillation (AF). There are limited data on the PolarX Cryoballoon. The study aimed to establish the safety, efficacy, and feasibility of same day discharge for Cryoballoon PVI.

METHODS AND RESULTS

Multi-centre study across 12 centres. Procedural metrics, safety profile, and procedural efficacy of the PolarX Cryoballoon with the Arctic Front Advance (AFA) Cryoballoon were compared in a cohort large enough to provide definitive comparative data. A total of 1688 patients underwent PVI with cryoablation (50% PolarX and 50% AFA). Successful PVI was achieved with 1677 (99.3%) patients with 97.2% (n = 1641) performed as day case procedures with a complication rate of <1%. Safety, procedural metrics, and efficacy of the PolarX Cryoballoon were comparable with the AFA cohort. The PolarX Cryoballoon demonstrated a nadir temperature of -54.6 ± 7.6°C, temperature at 30 s of -38.6 ± 7.2°C, time to -40°C of 34.1 ± 13.7 s, and time to isolation of 49.8 ± 33.2 s. Independent predictors for achieving PVI included time to reach -40°C [odds ratio (OR) 1.34; P < 0.001] and nadir temperature (OR 1.24; P < 0.001) with an optimal cut-off of ≤34 s [area under the curve (AUC) 0.73; P < 0.001] and nadir temperature of ≤-54.0°C (AUC 0.71; P < 0.001), respectively.

CONCLUSIONS

This large-scale UK multi-centre study has shown that Cryoballoon PVI is a safe, effective day case procedure. PVI using the PolarX Cryoballoon was similarly safe and effective as the AFA Cryoballoon. The cryoablation metrics achieved with the PolarX Cryoballoon were different to that reported with the AFA Cryoballoon. Modified cryoablation targets are required when utilizing the PolarX Cryoballoon.

Pulsed Field or Conventional Thermal Ablation for Paroxysmal Atrial Fibrillation

BACKGROUND

Catheter-based pulmonary vein isolation is an effective treatment for paroxysmal atrial fibrillation. Pulsed field ablation, which delivers microsecond high-voltage electrical fields, may limit damage to tissues outside the myocardium. The efficacy and safety of pulsed field ablation as compared with conventional thermal ablation are not known.

METHODS

In this randomized, single-blind, noninferiority trial, we assigned patients with drug-refractory paroxysmal atrial fibrillation in a 1:1 ratio to undergo pulsed field ablation or conventional radiofrequency or cryoballoon ablation. The primary efficacy end point was freedom from a composite of initial procedural failure, documented atrial tachyarrhythmia after a 3-month blanking period, antiarrhythmic drug use, cardioversion, or repeat ablation. The primary safety end point included acute and chronic device- and procedure-related serious adverse events.

RESULTS

A total of 305 patients were assigned to undergo pulsed field ablation, and 302 were assigned to undergo thermal ablation. At 1 year, the primary efficacy end point was met (i.e., no events occurred) in 204 patients (estimated probability, 73.3%) who underwent pulsed field ablation and 194 patients (estimated probability, 71.3%) who underwent thermal ablation (between-group difference, 2.0 percentage points; 95% Bayesian credible interval, -5.2 to 9.2; posterior probability of noninferiority, >0.999). Primary safety end-point events occurred in 6 patients (estimated incidence, 2.1%) who underwent pulsed field ablation and 4 patients (estimated incidence, 1.5%) who underwent thermal ablation (between-group difference, 0.6 percentage points; 95% Bayesian credible interval, -1.5 to 2.8; posterior probability of noninferiority, >0.999).

CONCLUSIONS

Among patients with paroxysmal atrial fibrillation receiving a catheter-based therapy, pulsed field ablation was noninferior to conventional thermal ablation with respect to freedom from a composite of initial procedural failure, documented atrial tachyarrhythmia after a 3-month blanking period, antiarrhythmic drug use, cardioversion, or repeat ablation and with respect to device- and procedure-related serious adverse events at 1 year. (Funded by Farapulse-Boston Scientific; ADVENT ClinicalTrials.gov number, NCT04612244.).

Differences in the feasibility, anatomical parameters predicting procedural difficulty, and isolation area of a left atrial posterior wall isolation using radiofrequency versus cryoballoon catheters

BACKGROUNDS

The difficulty and outcome of the adjunctive left atrial posterior wall isolation (LAPWI) in patients with persistent atrial fibrillation (PersAF) may be affected by the ablation energy used. This study aimed to compare the completion rate, anatomical parameters predicting procedural difficulty, and the isolation area of a LAPWI between the use of radiofrequency (RFA) and cryoballoon ablation (CBA).

METHODS

We enrolled 95 and 93 patients with PersAF who underwent pulmonary vein isolation (PVI)+LAPWI using RFA (RF group) and CBA (CB group), respectively. Preoperative computed tomography was used to evaluate the anatomical features associated with an incomplete LAPWI. Post-ablation 3-dimensional maps were analyzed to quantify the isolation area.

RESULTS

The completion rate of the LAPWI was significantly higher in the RF group than the CB group without touch-up RFA (88.4% vs. 72.0%; p = .005). Predictors of incomplete LAPWI were a longer left inferior pulmonary vein (LIPV)-esophageal distance (p < .001) for RFA and a steeper angle of the LAPW (p < .001) and longer transverse LAPW diameter (p = .016) for CBA. The isolated non-PV area with RFA or CBA alone was significantly greater in the CB group than the RF group (27.5 ± 9.5 cm2 vs. 22.9 ± 6.9 cm2 ; p < .001).

CONCLUSION

The position of the esophagus at a distance from the LIPV was associated with an incomplete LAPWI using RFA, while a steeper angle of the LAPW and transverse enlargement of the LAPW were associated with that using CBA. The completion rate of the LAPWI was higher with RFA, but the isolation area outside of the PVs was greater with CBA.

Safety and acute efficacy of catheter ablation for atrial fibrillation with pulsed field ablation vs thermal energy ablation: A meta-analysis of single proportions

Background

Pulsed field ablation (PFA) has emerged as a novel energy source for the ablation of atrial fibrillation (AF) using ultrarapid electrical pulses to induce cell death via electroporation.

Objective

The purpose of this study was to compare the safety and acute efficacy of ablation for AF with PFA vs thermal energy sources.

Methods

We performed an extensive literature search and systematic review of studies that evaluated the safety and efficacy of ablation for AF with PFA and compared them to landmark clinical trials for ablation of AF with thermal energy sources. Freeman-Tukey double arcsine transformation was used to establish variance of raw proportions followed by the inverse with the random-effects model to combine the transformed proportions and generate the pooled prevalence and 95% confidence interval (CI).

Results

We included 24 studies for a total of 5203 patients who underwent AF ablation. Among these patients, 54.6% (n = 2842) underwent PFA and 45.4% (n = 2361) underwent thermal ablation. There were significantly fewer periprocedural complications in the PFA group (2.05%; 95% CI 0.94-3.46) compared to the thermal ablation group (7.75%; 95% CI 5.40-10.47) (P = .001). When comparing AF recurrence up to 1 year, there was a statistically insignificant trend toward a lower prevalence of recurrence in the PFA group (14.24%; 95% CI 6.97-23.35) compared to the thermal ablation group (25.98%; 95% CI 15.75-37.68) (P = .132).

Conclusion

Based on the results of this meta-analysis, PFA was associated with lower rates of periprocedural complications and similar rates of acute procedural success and recurrent AF with up to 1 year of follow-up compared to ablation with thermal energy sources.

Selection of patients for hybrid ablation procedure

Catheter ablation for treatment of symptomatic non-paroxysmal atrial fibrillation remains challenging. Clinical failure and need for continued medical therapy or repeat ablation is common, especially in more advanced forms of atrial fibrillation. Hybrid ablation has emerged as a more effective and safe therapy than endocardial-only ablation particularly for longstanding persistent atrial fibrillation as demonstrated by the randomized controlled CONVERGE trial. Hybrid ablation requires collaboration of electrophysiologists and cardiac surgeons to develop specific workflows. This review describes the Hybrid Convergent approach in the context of available ablation options and offers guidance for workflow development and patient selection.

Single-shot technique of cryoablation for atrial fibrillation has comparable effective and safety outcomes compared to standard technique: insights from multiple clinical studies

Background

Although there are many freezing protocols available, the optimal freezing dose is still not determined. We aimed to evaluate the effectiveness and safety of different freeze strategies of CBA in the treatment of AF.

Methods

PubMed, Cochrane Library, Web of Science, and Embase were searched up to 1st December 2022. Studies comparing the outcomes between single-shot technique and standard technique of cryoablation were included. Subgroup analysis identified potential determinants for single-shot technique procedure.

Results

Our search resulted in 3407 records after deduplication. A total of 17 qualified studies met our inclusion criteria. Compared with standard technique, single-shot technique of cryoablation has a comparable rate of freedom from AF/AT(RR 1.00; P = 0.968), a trend for lower rate of procedure complications (RR 0.80; P = 0.069), a lower rate in transient phrenic paralysis (t-PNP) (RR 0.67; P = 0.038), a similar rate in persistent phrenic paralysis (per-PNP) (RR 1.15; P = 0.645), as well as a comparable procedure parameters. Importantly, potentially significant treatment covariable interactions in procedure complications were found in freeze strategy subgroup, male proportion subgroup and age subgroup, including single-shot freeze (RR 1.02; P = 0.915) and TTI-guided (RR 0.63; P = 0.007) with interaction P = 0.051, high male proportion (RR 0.54; P = 0.005) and a low male proportion (RR 0.94; P = 0.759) with interaction P = 0.074, as well as age ≥ 65 (RR0.91; P = 0.642) and age <65 (RR 0.54; P = 0.006),interaction P = 0.090. Meanwhile, only one significant treatment covariable interactions in procedure complications was found in the hypertension subgroup, including HT > 60% (RR 0.89; P = 0.549) and HT ≤ 60% (RR 0. 46; P < 0.01) with interaction P = 0.043.

Conclusions

Our study suggested that single-shot technique of cryoablation has comparable effective and safety outcomes for AF ablation compared to standard technique.

Tic-Tac: A Translational Approach in Mechanisms Associated with Irregular Heartbeat and Sinus Rhythm Restoration in Atrial Fibrillation Patients

Atrial fibrillation (AF) is a prevalent cardiac condition predominantly affecting older adults, characterized by irregular heartbeat rhythm. The condition often leads to significant disability and increased mortality rates. Traditionally, two therapeutic strategies have been employed for its treatment: heart rate control and rhythm control. Recent clinical studies have emphasized the critical role of early restoration of sinus rhythm in improving patient outcomes. The persistence of the irregular rhythm allows for the progression and structural remodeling of the atria, eventually leading to irreversible stages, as observed clinically when AF becomes permanent. Cardioversion to sinus rhythm alters this progression pattern through mechanisms that are still being studied. In this review, we provide an in-depth analysis of the pathophysiological mechanisms responsible for maintaining AF and how they are modified during sinus rhythm restoration using existing therapeutic strategies at different stages of clinical investigation. Moreover, we explore potential future therapeutic approaches, including the promising prospect of gene therapy.

CLOSE-Guided Pulmonary Vein Isolation to Treat Persistent Atrial Fibrillation: 1-Year Outcome

BACKGROUND

CLOSE-guided pulmonary vein isolation (PVI) is based on contiguous and optimized (Ablation Index-guided) radiofrequency lesions. The efficacy of CLOSE-guided PVI in persistent atrial fibrillation (AF) treatment has been poorly evaluated.

METHODS

In two centers, 50 patients eligible for persistent AF ablation underwent CLOSE-guided PVI (Ablation Index ≥ 450 at the anterior wall, ≥300 at posterior wall, intertag distance ≤ 6 mm). If PVI failed to restore sinus rhythm (SR), electrical cardioversion (ECV) was performed. Atrial substrate modification (ASM) was performed only if PVI and ECV failed to restore SR. Recurrence was defined as any recorded episode of AF, atrial tachycardia (AT) or atrial flutter (AFL) > 30 s on Holter electrocardiographs at 3, 6 and 12 months.

RESULTS

From the 50 patients (64 ± 10 years, 14% long-standing persistent AF), SR was restored by ECV in 34 patients (68%) 56 ± 38 days prior to ablation. On the day of ablation, 42 patients (84%) were on class I-III anti-arrhythmic drug therapy (ADT) and the rhythm was AF in 23/50 patients. PVI was achieved in all patients; after PVI, ECV was required in 21 patients and ASM in 1 patient. The mean procedure time, radiofrequency time and fluoroscopy time were 141 ± 33 min, 23 ± 7 min and 7 ± 6 min, respectively. At 12 months, single-procedure freedom from AF/AT/AFL was 80%, with 19 patients (38%) receiving class I-III ADT.

CONCLUSIONS

In a population of patients with persistent AF monitored with intermittent cardiac rhythm recordings, CLOSE-guided PVI resulted in high single-procedure arrhythmia-free survival at 1 year. Future large-scale studies involving continuous cardiac monitoring are necessary.

Efficacy and safety of hybrid epicardial and endocardial ablation versus endocardial ablation in patients with persistent and longstanding persistent atrial fibrillation: a randomised, controlled trial

Background

Endocardial catheter ablation (CA) has limited long-term benefit for persistent and longstanding persistent atrial fibrillation (PersAF/LSPAF). We hypothesized hybrid epicardial-endocardial ablation (HA) would have superior effectiveness compared to CA, including repeat (rCA), in PersAF/LSPAF.

Methods

CEASE-AF (NCT02695277) is a prospective, multi-center, randomized controlled trial. Nine hospitals in Poland, Czech Republic, Germany, United Kingdom, and the Netherlands enrolled eligible participants with symptomatic, drug refractory PersAF and left atrial diameter (LAD) > 4.0 cm or LSPAF. Randomization was 2:1 to HA or CA by an independent statistician and stratified by site. Treatment assignments were masked to the core rhythm monitoring laboratory. For HA, pulmonary veins (PV) and left posterior atrial wall were isolated with thoracoscopic epicardial ablation including left atrial appendage exclusion. Endocardial touch-up ablation was performed 91-180 days post-index procedure. For CA, endocardial PV isolation and optional substrate ablation were performed. rCA was permitted between days 91-180. Primary effectiveness was freedom from AF/atrial flutter/atrial tachycardia >30-s through 12-months absent class I/III anti-arrhythmic drugs except those not exceeding previously failed doses. It was assessed in the modified intention-to-treat (mITT) population who had the index procedure and follow-up data. Major complications were assessed in the ITT population who had the index procedure. Thirty-six month follow-up continues.

Findings

Enrollment began November 20, 2015 and ended May 22, 2020. In 154 ITT patients (102 HA; 52 CA), 75% were male, mean age was 60.7 ± 7.9 years, mean LAD was 4.7 ± 0.4 cm, and 81% had PersAF. Primary effectiveness was 71.6% (68/95) in HA versus 39.2% (20/51) in CA (absolute benefit increase: 32.4% [95% CI 14.3%-48.0%], p < 0.001). Major complications through 30-days after index procedures plus 30-days after second stage/rCA were similar (HA: 7.8% [8/102] versus CA: 5.8% [3/52], p = 0.75).

Interpretation

HA had superior effectiveness compared to CA/rCA in PersAF/LSPAF without significant procedural risk increase.

Funding

AtriCure, Inc.

Radiofrequency versus cryoballoon catheter ablation in patients with persistent atrial fibrillation: A randomized trial

INTRODUCTION

Patients with persistent atrial fibrillation (AF) represent a challenging population for rhythm control therapies. Catheter ablation (CA) with pulmonary vein isolation (PVI) is an effective treatment option for the reduction of the arrhythmic burden. Data regarding the comparability between radiofrequency (RF) and cryoballoon ablation (CRYO) in persistent AF are limited.

METHODS

This is a prospective, randomized, single-center study designed to compare the efficacy in terms of rhythm control between RF and CRYO in persistent AF. Eligible participants were randomized 2:1 in two arms: RF and CRYO. The primary endpoint of the study was arrhythmia relapse in the early postprocedural period (first 3 months) and in the middle term follow-up (3 months to 12 months). Secondary endpoints included procedure duration, fluoroscopy time, and complications.

RESULTS

A total of 199 patients participated in the study (133 patients in the RF arm, 66 in the CRYO arm). No statistically significant difference occurred between the two groups regarding the primary endpoint (recurrences ≤3 months: 35.5% RF vs. 37.9% CRYO, p .755, recurrences >3 months: 26.3% RF vs. 27.3% CRYO, p .999). From the secondary endpoints, CRYO was a procedure of significantly shorter duration (75.15 ± 17.21 in CRYO vs. 136.6 ± 43.33 in RF group, p < .05).

CONCLUSION

CRYO and RF ablation appear to be equally effective for rhythm control in patients with persistent AF. CRYO ablation is advantageous in terms of procedure duration.

Outcomes of adjunct posterior wall isolation in atrial fibrillation patients with cardiac implantable electronic devices

BACKGROUND

Although pulmonary vein isolation (PVI) remains the cornerstone of catheter ablation of atrial fibrillation (AF), several studies have illustrated clinical benefits associated with PVI with posterior wall isolation (PWI).

METHODS

This retrospective study investigated the outcomes of PVI alone versus PVI+PWI performed using the cryoballoon in patients with cardiac implantable electronic devices (CIEDs) and paroxysmal AF (PAF) or persistent AF (PersAF).

RESULTS

Acute PVI was achieved in all patients using cryoballoon ablation. Compared to PVI alone, PVI+PWI was associated with longer cryoablation, fluoroscopy, and total procedure times. Adjunct radiofrequency was required to complete PWI in 29/77 patients (37.7%). Adverse events were similar with PVI alone versus PVI+PWI. But at 24 ± 7 months of follow-up, not only cryoballoon PVI+PWI was associated with improved freedom from recurrent AF (74.3% vs. 46.0%, P = .007) and all atrial tachyarrhythmias (71.4% vs. 38.1%, P = .001) in patients with PersAF, cryoballoon PVI+PWI also yielded greater freedom from AF (88.1% vs. 63.7%, P = .003) and all atrial tachyarrhythmias (83.3% vs. 60.8%, P = .008) in those with PAF. Additionally, PVI+PWI was associated with higher reductions in atrial tachyarrhythmia burden (97.9% vs. 91.6%, P < .001), need for cardioversion (5.2% vs. 23.6%, P < .001) and repeat catheter ablation (10.4% vs. 26.1%, P = .005), and a longer time-to-arrhythmia recurrence (16 ± 6 months vs. 8 ± 5 months, P < .001) in both PersAF and PAF patients.

CONCLUSION

In CIED patients with PersAF or PAF, cryoballoon PVI+PWI is associated with a greater freedom from recurrent AF and atrial tachyarrhythmias, as compared to PVI alone during long-term follow-up.

Multicenter retrospective database evaluation of Takotsubo syndrome in subjects undergoing catheter ablation for atrial fibrillation

Background

Intracardiac catheter ablation for atrial fibrillation with pulmonary vein isolation may result in Takotsubo syndrome (TS), but the frequency, predisposing factors (age, sex, mental health disorders), and outcomes are currently unknown. This study sought to assess the frequency, predisposing factors, and outcomes of subjects who underwent intracardiac catheter ablation for atrial fibrillation with pulmonary vein isolation and were diagnosed with TS.

Methods

This was a retrospective observational cohort study utilizing TriNetX® electronic health record (EHR) data. We included subjects aged older than 18 years who underwent intracardiac catheter ablation for atrial fibrillation with pulmonary vein isolation. The study population was divided into two groups (no TS diagnostic code presence and TS diagnostic code presence). We analyzed the distributions of age, sex, race, diagnostic codes, common terminology procedures (CPT), and vasoactive medication codes and examined mortality rate within 30 days.

Results

We included 69,116 subjects. Of these, 27 (0.04%) had a TS diagnostic code, the cohort was comprised mostly of females [17 (63.0%)], and 1 (3.7%) death within 30 days was reported. There were no significant differences in age and frequency of mental health disorders between those patients in TS and non-TS cohorts. Adjusting for age, sex, race, ethnicity, patient regionality, and mental health disorder diagnostic code, those patients who developed TS had a significantly higher odds of dying in 30 days after catheter ablation compared to those without TS (OR = 15.97, 95% CI: 2.10-121.55, p = .007).

Conclusions

Approximately 0.04% of subjects who underwent intracardiac catheter ablation of atrial fibrillation by pulmonary vein isolation had a subsequent diagnostic code of TS. Further study is needed to determine whether there are predisposing factors associated with the development of TS in subjects who undergo catheter ablation of atrial fibrillation by pulmonary vein isolation.

Treatment of pathophysiologic propagation outside of the pulmonary veins in retreatment of atrial fibrillation patients: RECOVER AF study

AIMS

RECOVER AF evaluated the performance of whole-chamber non-contact charge-density mapping to guide the ablation of non-pulmonary vein (PV) targets in persistent atrial fibrillation (AF) patients following either a first or second failed procedure.

METHODS AND RESULTS

RECOVER AF was a prospective, non-randomized trial that enrolled patients scheduled for a first or second ablation retreatment for recurrent AF. The PVs were assessed and re-isolated if necessary. The AF maps were used to guide the ablation of non-PV targets through elimination of pathologic conduction patterns (PCPs). Primary endpoint was freedom from AF on or off antiarrhythmic drugs (AADs) at 12 months. Patients undergoing retreatment with the AcQMap System (n = 103) were 76% AF-free at 12 months [67% after single procedure (SP)] on or off AADs (80% free from AF on AADs). Patients who had only received a pulmonary vein isolation (PVI) prior to study treatment of non-PV targets with the AcQMap System were 91% AF-free at 12 months (83% SP). No major adverse events were reported.

CONCLUSION

Non-contact mapping can be used to target and guide the ablation of PCPs beyond the PVs in persistent AF patients returning for a first or second retreatment with 76% freedom from AF at 12 months. The AF freedom was particularly high, 91% (43/47), for patients enrolled having only a prior de novo PVI, and freedom from all atrial arrhythmias for this cohort was 74% (35/47). These early results are encouraging and suggest that guiding individualized targeted ablation of PCPs may therefore be advantageous to target at the earliest opportunity in patients with persistent AF.

Pulsed Field Ablation for the Treatment of Atrial Fibrillation: PULSED AF Pivotal Trial

BACKGROUND

Pulsed field ablation uses electrical pulses to cause nonthermal irreversible electroporation and induce cardiac cell death. Pulsed field ablation may have effectiveness comparable to traditional catheter ablation while preventing thermally mediated complications.

METHODS

The PULSED AF pivotal study (Pulsed Field Ablation to Irreversibly Electroporate Tissue and Treat AF) was a prospective, global, multicenter, nonrandomized, paired single-arm study in which patients with paroxysmal (n=150) or persistent (n=150) symptomatic atrial fibrillation (AF) refractory to class I or III antiarrhythmic drugs were treated with pulsed field ablation. All patients were monitored for 1 year using weekly and symptomatic transtelephonic monitoring; 3-, 6-, and 12-month ECGs; and 6- and 12-month 24-hour Holter monitoring. The primary effectiveness end point was freedom from a composite of acute procedural failure, arrhythmia recurrence, or antiarrhythmic escalation through 12 months, excluding a 3-month blanking period to allow recovery from the procedure. The primary safety end point was freedom from a composite of serious procedure- and device-related adverse events. Kaplan-Meier methods were used to evaluate the primary end points.

RESULTS

Pulsed field ablation was shown to be effective at 1 year in 66.2% (95% CI, 57.9 to 73.2) of patients with paroxysmal AF and 55.1% (95% CI, 46.7 to 62.7) of patients with persistent AF. The primary safety end point occurred in 1 patient (0.7%; 95% CI, 0.1 to 4.6) in both the paroxysmal and persistent AF cohorts.

CONCLUSIONS

PULSED AF demonstrated a low rate of primary safety adverse events (0.7%) and provided effectiveness consistent with established ablation technologies using a novel irreversible electroporation energy to treat patients with AF.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT04198701.

Left atrial appendage occlusion combined with cryoballoon or radiofrequency ablation: One-year follow-up comparison

Background

A one-stop procedure involving catheter ablation and left atrial appendage occlusion (LAAO) is an option for high-risk atrial fibrillation patients. Few studies have reported the efficacy and safety of cryoballoon ablation (CBA) combined with LAAO, and no studies have compared the combination of LAAO with CBA or radiofrequency ablation (RFA).

Methods

A total of 112 patients were enrolled in the present study; 45 patients received CBA combined with LAAO (group 1), and 67 patients received RFA combined with LAAO (group 2). Patient follow-up was performed for 1 year to detect peri-device leaks (PDLs) and safety outcomes (defined as a composite of peri-procedural and follow-up adverse events).

Results

The number of PDLs at the median 59 days follow-up was comparable between the two groups (33.3% in group 1 vs. 37.3% in group 2, p = 0.693). Safety outcomes were also comparable between the two groups (6.7% in group 1 vs. 7.5% in group 2, p = 1.000). Multivariable regression showed that PDLs risk and safety outcomes were all similar between the two groups. Subgroup analysis of PDLs indicated no significant differences. Follow-up safety outcomes were related to anticoagulant medication, and patients without PDLs were more likely to discontinue antithrombotic therapy. The total procedure and ablation times were all significantly shorter for group 1.

Conclusion

When compared with left atrial appendage occlusion combined with radiofrequency, left atrial appendage occlusion combined with cryoballoon ablation has the same risk of peri-device leaks and safety outcomes, but the procedure time was significantly reduced.

Differences in postablation cardiac MRI scar between radiofrequency and cryoballoon ablation: A DECAAF II subanalysis

INTRODUCTION

Pulmonary vein isolation (PVI) using radiofrequency (RF) and cryoballoon (Cryo) ablation are standard approaches for rhythm control in patients with symptomatic atrial fibrillation. Both strategies create scars in the left atrium (LA). There have been few studies investigating the difference in scar formation between patients undergoing RF and Cryo using cardiac magnetic resonance (CMR) imaging.

METHODS

The current study is a subanalysis of the control arm of the Delayed-Enhancement MRI Determinant of Successful Catheter Ablation of Atrial Fibrillation study (DECAAF II). The study was a multicenter, randomized, controlled, single-blinded trial that evaluated atrial arrhythmia recurrence (AAR) between PVI alone and PVI plus CMR atrial fibrosis-guided ablation. Preablation CMR and 3- to 6-month postablation CMR were obtained to assess baseline LA fibrosis and scar formation, respectively.

RESULTS

Of the 843 patients randomized in the DECAAF II trial, we analyzed the 408 patients in the primary analysis control arm that received standard PVI. Five patients received combined RF and Cryo ablations, so they were excluded from this subanalysis. Of the 403 patients analyzed, 345 underwent RF and 58 Cryo. The average procedure duration was 146 min for RF and 103 min for Cryo (p = .001). The rate of AAR at ~15 months occurred in 151 (43.8%) patients in the RF group and 28 (48.3%) patients in the Cryo group (p = .62). On 3-month post-CMR, the RF arm had significantly more scar (8.8% vs. 6.4%, p = .001) compared to Cryo. Patients with ≥6.5% LA scar (p < .001) and ≥2.3% LA scar around the PV antra (p = .01) on 3-month post-CMR had less AAR independent of the ablation technique. Cryo caused a greater percentage of right and left pulmonary vein (PV) antral scar (p = .04, p = .02) and less non-PV antral scar (p = .009) compared to RF. On Cox regression, Cryo patients free of AAR had a greater percentage of left PV antral scar (p = .01) and less non-PV antral scar (p = .004) compared to RF free of AAR.

CONCLUSION

In this subanalysis of the control arm of the DECAAF II trial, we observed that Cryo formed a more significant percentage of PV antral scar and less non-PV antral scar compared to RF. Post ablation LA scar ≥6.5% predicted freedom from AAR, independent of ablation technique. These findings may have prognostic implications in ablation technique selection and freedom from AAR.

Relationship between pre-procedural non-ischemic ST-segment depression and the clinical outcomes after catheter ablation in persistent atrial fibrillation patients

BACKGROUND

ST-segment depression suggests the presence of coronary artery disease (CAD) during sinus rhythm, but the clinical significance, including the outcomes after catheter ablation (CA), in atrial fibrillation (AF) patients remain unknown.

METHODS

The present study included persistent AF (PerAF) patients from the Osaka Rosai Atrial Fibrillation ablation (ORAF) registry who underwent an initial ablation and had no history of CAD. We assigned the patients based on the presence of ST-segment depression before CA and evaluated the impact of relevant factors on ST-segment depression and the relationship between ST-segment depression, including leads locations (anterior leads, inferior leads, and lateral leads) or depression type (upsloping, horizontal, and downsloping) or the degree of ST-segment depression and late recurrence of AF (LRAF).

RESULTS

This study population included a total of 551 patients of whom 189 had ST-segment depression. The median follow-up duration was 397 days and LRAF occurred in 195 patients. By multiple regression analysis, diabetes mellitus, hemoglobin, brain natriuretic peptide, left ventricular ejection fraction, and left atrial diameter were significant determinants of ST-segment depression before CA. Kaplan-Meier analysis demonstrated that the patients with ST-segment depression had a significantly greater risk of LRAF than those without (p < 0.001). Multivariate Cox proportional hazards analysis showed ST-segment depression was independently and significantly associated with a higher risk of LRAF (p < 0.001). The patients with ST-segment depression ≥0.15 mV had a significantly higher risk of LRAF than those with ST-segment depression ≥0.15 mV (p < 0.001). No significant differences among the ST-segment depression lead locations and ST-segment depression type were observed.

CONCLUSION

Non-ischemic ST-segment depression during AF rhythm was significantly associated with LRAF post CA in PerAF patients.

Immunohistochemical characteristics of local sites that trigger atrial arrhythmias in response to high-frequency stimulation

AIMS

The response to high frequency stimulation (HFS) is used to locate putative sites of ganglionated plexuses (GPs), which are implicated in triggering atrial fibrillation (AF). To identify topological and immunohistochemical characteristics of presumed GP sites functionally identified by HFS.

METHODS AND RESULTS

Sixty-three atrial sites were tested with HFS in four Langendorff-perfused porcine hearts. A 3.5 mm tip quadripolar ablation catheter was used to stimulate and deliver HFS to the left and right atrial epicardium, within the local atrial refractory period. Tissue samples from sites triggering atrial ectopy/AF (ET) sites and non-ET sites were stained with choline acetyltransferase (ChAT) and tyrosine hydroxylase (TH), for quantification of parasympathetic and sympathetic nerves, respectively. The average cross-sectional area (CSA) of nerves was also calculated. Histomorphometry of six ET sites (9.5%) identified by HFS evoking at least a single atrial ectopic was compared with non-ET sites. All ET sites contained ChAT-immunoreactive (ChAT-IR) and/or TH-immunoreactive nerves (TH-IR). Nerve density was greater in ET sites compared to non-ET sites (nerves/cm2: 162.3 ± 110.9 vs. 69.65 ± 72.48; P = 0.047). Overall, TH-IR nerves had a larger CSA than ChAT-IR nerves (µm2: 11 196 ± 35 141 vs. 2070 ± 5841; P < 0.0001), but in ET sites, TH-IR nerves were smaller than in non-ET sites (µm2: 6021 ± 14 586 vs. 25 254 ± 61 499; P < 0.001).

CONCLUSIONS

ET sites identified by HFS contained a higher density of smaller nerves than non-ET sites. The majority of these nerves were within the atrial myocardium. This has important clinical implications for devising an effective therapeutic strategy for targeting autonomic triggers of AF.

Pulmonary vein isolation alone or in combination with substrate modulation after electrical cardioversion failure in patients with persistent atrial fibrillation: The PACIFIC trial: Study design

INTRODUCTION

Pulmonary vein isolation (PVI) is effective at treating 50% of unselected patients with persistent atrial fibrillation (AF). Alternatively, PVI combined with a new ablation strategy entitled the Marshall-PLAN ensures a 78% 1-year sinus rhythm (SR) maintenance rate in the same population. However, a substantial subset of patients could undergo the Marshall-PLAN unnecessarily. It is therefore essential to identify those patients who can be treated with PVI alone versus those who may truly benefit from the Marshall-PLAN before ablation is performed. In this context, we hypothesized that electrical cardioversion (EC) could help to select the most appropriate strategy for each patient.

METHODS

In this multicentre, prospective, randomized study, patients with AF recurrence within 4 weeks after EC will be randomized 1:1 to PVI alone or the Marshall-PLAN. Conversely, patients in whom SR is maintained for ≥4 weeks after EC will be treated with PVI only and included in a prospective registry. The primary endpoint will be the 1-year SR maintenance rate after a single ablation procedure.

RESULTS AND CONCLUSION

The Marshall-PLAN might be necessary in patients with an advanced degree of persistent AF (i.e., where SR is not maintained for ≥4 uninterrupted weeks after EC). Conversely, in patients with mild or moderate persistent AF (i.e., where SR is maintained for ≥4 weeks after EC), PVI alone might be a sufficient ablation strategy. The PACIFIC trial is the first study designed to assess whether rhythm monitoring after EC could help to identify patients who should undergo adjunctive ablation strategies beyond PVI.

Hybrid epicardial-endocardial ablation for long-standing persistent atrial fibrillation: A subanalysis of the CONVERGE Trial

Background

Favorable clinical outcomes are difficult to achieve in long-standing persistent atrial fibrillation (LSPAF) with catheter ablation (CA). The CONVERGE (Convergence of Epicardial and Endocardial Ablation for the Treatment of Symptomatic Persistent Atrial FIbrillation) trial evaluated the effectiveness of hybrid convergent (HC) ablation vs endocardial CA.

Objective

The study sought to evaluate the safety and effectiveness of HC vs CA in the LSPAF subgroup from the CONVERGE trial.

Methods

The CONVERGE trial was a prospective, multicenter, randomized trial that enrolled 153 patients at 27 sites. A post hoc analysis was performed on LSPAF patients. The primary effectiveness was freedom from atrial arrhythmias off new or increased dose of previously failed or intolerant antiarrhythmic drugs (AADs) through 12 months. The primary safety endpoint was major adverse event incidence through 30 days with HC. Key secondary effectiveness measures included (1) percent of patients achieving ≥90% AF burden reduction vs baseline and (2) AF freedom.

Results

Sixty-five patients (42.5% of total enrollment) had LSPAF; 38 in HC and 27 in CA. Primary effectiveness was 65.8% (95% confidence interval [CI] 50.7%-80.9%) with HC vs 37.0% (95% CI 5.1%-52.4%) with CA (P = .022). Through 18 months, these rates were 60.5% (95% CI 50.0%-76.1%) with HC vs 25.9% (95% CI 9.4%-42.5%) with CA (P = .006). Secondary effectiveness rates were higher than CA with HC at 12 and 18 months. Freedom from atrial arrhythmias off AADs was 52.6% (95% CI 36.8%-68.5%) and 47.4% (95% CI 31.5%-63.2%) with HC at 12 and 18 months vs 25.9% (95% CI 9.4%-42.5%) and 22.2% (95% CI 6.5%-37.9%) with CA, respectively (12 months: P = .031; 18 months: P = .038). Three (7.9%) major adverse events occurred within 30 days of HC.

Conclusion

Post hoc analysis demonstrated effectiveness and acceptable safety of HC compared with CA in LSPAF.

Contact force catheter ablation for the treatment of persistent atrial fibrillation: Results from the PERSIST-END study

INTRODUCTION

Use of a novel magnetic sensor enabled optical contact force ablation catheter has been established to be safe and effective for treatment of symptomatic drug-refractory paroxysmal atrial fibrillation (AF) but has yet to be demonstrated in the persistent AF (PersAF) population.

METHODS

PERSIST-END was a multicenter, prospective, nonrandomized, investigational study designed to demonstrate the safety and effectiveness of TactiCath™ Ablation Catheter, Sensor Enabled™(SE) (TactiCath SE) for use in the treatment of subjects with documented PersAF refractory or intolerant to at least one Class I/III AAD. The ablation strategy included pulmonary vein isolation and additional targets at physician discretion. Follow-up through 15-months, including a 3-month blanking period and 3-month therapy consolidation period, was performed with cardiac event and Holter monitoring. Primary safety, primary effectiveness, clinical success, and quality of life (QOL) endpoints were analyzed.

RESULTS

Of 224 subjects enrolled at 21 investigational sites in the United States and Australia, 223 underwent ablation with the investigational catheter. The primary safety event rate was 3.1% (seven events in seven subjects). The Kaplan-Meier estimate of freedom from AF/atrial flutter/atrial tachycardia recurrence at 15-months was 61.6% and clinical success at 15 months was 89.8%. Subject QOL significantly improved following ablation as assessed via AFEQT (31.6 point increase, p < .0001) and EQ-5D-5L (10.7 point increase, p < .0001) and was met with a 53% reduction in all cause cardiovascular healthcare utilization.

CONCLUSION

The sensor-enabled force-sensing catheter is safe and effective for the treatment of drug refractory recurrent symptomatic PersAF, reducing arrhythmia recurrence while improving QOL and healthcare utilization.

Relationship between left atrial appendage peak flow velocity and nonvalvular atrial fibrillation recurrence after cryoablation

Background

Previous studies revealed the connection between left atrial appendage peak flow velocity (LAA-PEV) and postoperative persistent atrial fibrillation (AF) recurrence. Yet, this association is not necessarily generalizable to persistent AF patients undergoing initial cryoballoon ablation due to current gaps in the literature.

Methods

We prospectively studied 74 consecutive individuals with persistent atrial fibrillation undergoing a cryoballoon ablation for the first time between January 2018 and January 2020. Before ablation, LAA-PEV was documented by transesophageal echocardiography (TEE). Subsequently, demographic information and other clinical characteristics of these participants were collected. A 96-h continuous cardiac monitor was reviewed regularly for recurrence of atrial fibrillation. Cox proportional hazards regression was used to investigate LAA-PEV as well as other clinical characteristics as a predictor of AF recurrence.

Results

Our study found that AF recurrences had lower LAA-PEV than those without AF recurrence. A nonlinear relationship between the LAA-PEV and AF recurrence was observed in this study, which had an inflection point of 34.9. Subgroup analysis of female participants showed that LAA-PEV had a positive correlation with AF recurrence [β = 0.8, 95% CI (0.7, 0.9), p < 0.05].

Conclusion

A low LAA-PEV is related to recurrence of atrial fibrillation and may predict AF recurrence after initial cryoballoon ablation for persistent atrial fibrillation. This finding may help improve treatment and care strategies for patients with persistent atrial fibrillation.

A Simplified Approach to Pulmonary Vein Visualization during Cryoballoon Ablation of Atrial Fibrillation

Background and Objectives: Selective pulmonary vein (PV) angiography has been established as the gold standard for PV visualization in cryoballoon (CB)-based pulmonary vein isolation (PVI). We sought to simplify this approach to reduce procedural complexity and radiation exposure. Materials and Methods: Patients with paroxysmal and recently diagnosed persistent AF undergoing CB-based PVI from January 2015 to December 2017 were retrospectively analyzed. Patients underwent either selective PV angiography or conventional left atrial (LA) angiography for PV visualization. Results: A total of 336 patients were analyzed. A total of 87 patients (26%) received PV angiography and 249 (74%) LA angiography. LA angiography required fewer cine-sequences for PV visualization, translating into a significant reduction in procedure duration, fluoroscopy time and dose area product. Additionally, less contrast medium was utilized. PV occlusion by the CB, CB temperature and time to isolation showed no significant differences. The number of CB applications and total application time (LA angiography: 1.4 ± 0.02 vs. PV Angiography: 1.6 ± 0.05; p < 0.0001; LA angiography: 297.9 ± 4.62 vs. PV-Angiography: 348.9 ± 11.03; p < 0.001, respectively) per vein were slightly but significantly higher in the PV angiography group. We observed no difference in late AF recurrence (24.7% LA angiography vs. 21.3% PV angiography; p = 0.2657). Conclusions: A simplified protocol, using LA angiography for PV visualization, entails a reduction in procedure time and radiation exposure while equally maintaining procedural efficiency and safety in both groups.

Cryoballoon ablation for atrial fibrillation in patients with heart failure with mildly reduced and preserved ejection fraction

AIMS

Limited data are available on the outcomes of cryoballoon ablation (CBA)-based pulmonary vein isolation (PVI) for atrial fibrillation (AF) in patients with heart failure (HF) with preserved ejection fraction (HFpEF) and mildly reduced ejection fraction (HFmrEF). The present study aimed to evaluate the safety and effectiveness of CBA in such patients.

METHODS AND RESULTS

Consecutive patients with AF referred for CBA-based PVI from two highly experienced electrophysiology centres were included in this retrospective study. Of 651 patients undergoing CBA, 471 cases were divided into four groups: No HF (n = 255), HFpEF (n = 101), HFmrEF (n = 78), and HF with reduced ejection fraction (n = 37). Similar early recurrence of atrial arrhythmia was found among groups (16.2% vs. 15.4% vs. 14.9% vs. 12.2%, P = 0.798), and no significant difference of long-term sinus rhythm (SR) maintenance was identified among the HFmrEF, HFpEF, and No HF groups (71.8% vs. 75.2% vs. 79.6%, P = 0.334). CBA is safe for patients with HFmrEF and HFpEF with similar complications compared with the No HF group (3.8% vs. 4.0% vs. 3.1%, P = 0.814). The reassessment of cardiac function after CBA showed that patients with HF indicated beneficial outcomes. Left atrial diameter (LAD) and left ventricular ejection fraction were significantly improved in the HFmrEF group. There were 41.6% of patients in the HFpEF group who were completely relieved from HF. LAD and New York Heart Association (NYHA) were associated with recurrence in the HFpEF and HFmrEF groups, and the maintenance of SR was an independent predictor of NYHA improvement for all HF groups.

CONCLUSIONS

Patients with HFmrEF and HFpEF could benefit from CBA with high SR maintenance and significant HF improvement.

Cryoballoon ablation of persistent atrial fibrillation for de novo pulmonary vein isolation: a single-center follow-up study

BACKGROUND

Pulmonary vein isolation (PVI) alone for persistent atrial fibrillation (PersAF) remains controversial. The characteristics of cryoballoon ablation (CBA) to treat PersAF and the blanking period recurrence are underreported.

METHODS

This study retrospectively analyzed patients with PersAF undergoing second-generation CBA for de novo PVI. The post-procedural efficacy and survival analysis were compared between patients with different PersAF durations. The multivariate Cox regression analysis was used to detect the risk factors for recurrence. Early and long-term recurrence were analyzed relative to each other.

RESULTS

A total of 329 patients were enrolled, with a median PersAF duration of 4.0 months (interquartile range: 2.0-12.0 months); 257 patients (78.1%) were male. Kaplan-Meier analysis of freedom from atrial fibrillation recurrence at 12, 24, and 30 months showed 71.0%, 58.5%, and 54.9%, respectively. Early PersAF had a relatively favorable survival rate and a narrow P-wave duration of restoring sinus rhythm compared with that of PersAF lasting more than three months (P < 0.05). The multivariate Cox regression analysis revealed that PersAF duration and left atrial anteroposterior diameter ≥ 42 mm were the risk factors for atrial fibrillation recurrence after CBA [hazard ratio (HR) = 1.89, 95% CI: 1.01-1.4, P = 0.042; HR = 3.6, 95% CI: 2.4-5.4, P < 0.001, respectively]. The blanking period recurrence predicted the long-term recurrence (P < 0.0001).

CONCLUSIONS

CBA of PersAF had safety and efficacy to reach de novo PVI. The PersAF duration and left atrial size were risk factors for atrial fibrillation recurrence after CBA. Blanking period recurrence was associated with long-term recurrence.

Persistent Atrial Fibrillation in Elderly Patients: Limited Efficacy of Pulmonary Vein Isolation

(1) Background: Cryoballoon pulmonary vein isolation (cryoPVI) is established for symptomatic paroxysmal atrial fibrillation (AF) treatment, but its value in persistent AF is less clear. In particular, limited data are available on its efficacy in elderly patients (≥75 years) with persistent AF. Age is an important modifier of AF progression and represents a risk-factor for AF recurrence. (2) Methods: Prospective, single-center observational study to evaluate the impact of age on efficacy and safety of cryoPVI in elderly patients. Primary efficacy endpoint was symptomatic AF recurrence after 90-day blanking period. Primary safety endpoints were death from any cause, procedure-associated complications or stroke/transient ischemic attack. Median follow-up was 17 months (range 3−24). (3) Results: We included 268 patients with persistent AF (94 ≥ 75 years of age). Multivariate Cox regression analysis identified age as the only independent factor influencing AF recurrence in the overall cohort (p = 0.006). To minimize confounding bias in efficacy and safety analysis of cryoPVI, we matched younger and elderly patients with respect to baseline characteristics. At 24 months, primary efficacy endpoint occurred in 13/69 patients <75 years and 31/69 patients ≥75 years of age (24 months Kaplan−Meier event-rate estimates, HR 0.34; 95% CI, 0.19 to 0.62; log-rank p = 0.0004). No differences were observed in the occurrence of safety end points. (4) Conclusions: Elderly (≥75 years) patients with persistent AF undergoing cryoPVI had an approximately threefold higher risk of symptomatic AF recurrence than matched younger patients. Accordingly, other treatment modalities may be evaluated in this population.

Cryoablation as a first-line therapy for atrial fibrillation: current status and future prospects

INTRODUCTION

Atrial fibrillation (AF) is a common chronic and progressive heart rhythm disorder. For those in whom sinus rhythm is desired, contemporary clinical practice guidelines recommend antiarrhythmic drugs (AADs) as the initial therapy. However, these medications have modest efficacy and are associated with significant adverse effects.

AREAS COVERED

The current article reviews the evidence surrounding first line catheter ablation, particularly the emerging evidence surrounding the use of cryoballoon ablation as a first-line therapy. The focus of the review is on the outcomes of arrhythmia freedom, quality of life, healthcare utilisation and safety. In addition, the article will review novel cryoablation systems.

EXPERT OPINION

: Recent evidence suggests that cryoballoon ablation significantly improves arrhythmia outcomes (e.g., freedom from any atrial tachyarrhythmia or symptomatic atrial tachyarrhythmia, reduction in arrhythmia burden), patient-reported outcomes (e.g., symptoms and quality of life), and healthcare resource utilization (e.g., hospitalization), without increasing the risk of adverse events. These findings are relevant to patients, providers, and healthcare systems, as it helps inform the decision-making regarding the initial choice of rhythm-control therapy in patients with treatment-naïve AF.

Comparison of cryoballoon and radiofrequency ablation for persistent atrial fibrillation: a systematic review and meta-analysis

BACKGROUND

There is limited data comparing radiofrequency (RF) and cryoballoon (CB) ablation for persistent atrial fibrillation (AF), which tends to have higher recurrence rates following ablation compared to paroxysmal AF.

METHODS

A systematic search of the Embase, PubMed, and Cochrane database was performed for studies comparing RF vs CB ablation for persistent AF. An inverse-variance random-effects model was used to calculate the composite effects.

RESULTS

One randomized and 9 observational studies were identified, with 1650 patients receiving CB and 1706 patients receiving RF ablation. Mean follow-up time ranged from 12 to 48 months. Freedom from recurrent atrial tachyarrhythmia was similar with the two modalities (HR 0.93, 95% CI 0.80 to 1.08, I² 0%). Total complications were similar in both groups (RR 1.05, 95% CI 0.73 to 1.53, I² 0%) although rates of phrenic nerve palsy (PNP) were greater with CB (RR 4.13, 95% CI 1.49 to 11.46, I² 0%). Shorter procedure times were observed with CB (mean reduction 43.77 min, 95% CI 66.45 to 21.09 min, I² 96%) with no difference in fluoroscopy time (mean difference 0.82 min, 95% CI - 11.92 to 13.55 min, I² 100%).

CONCLUSIONS

In persistent AF patients, CB ablation has similar efficacy and overall safety as compared to RF ablation. While CB is associated with significantly shorter procedure times, the improved procedural efficiency with CB is offset by increased rates of PNP and the potential need for touch-up RF ablation.

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.