The efficacy and safety of left atrial low-voltage area guided ablation for recurrence prevention compared to pulmonary vein isolation alone in patients with persistent atrial fibrillation trial: Design and rationale

Pacing Cycle Length-Dependent Electrophysiological Changes in Left Atrium: Poor Validity of Using Low Voltage Area and Slow Conduction Area under Specific Pacing Cycle Length as Absolute Substrates of Atrial Fibrillation

BACKGROUND

Pacing cycle length (PCL)-dependent changes in left atrial (LA) electrophysiological properties have not been fully elucidated.

OBJECTIVE

To elucidate these changes using a high-resolution mapping system.

METHODS

Forty-eight patients underwent atrial fibrillation ablation with RHYTHMIA HDx™. Paired LA maps under a baseline PCL (600 ms) and rapid PCL (300 ms) were acquired after pulmonary vein isolation under right atrial appendage pacing. The PCL-dependent change in the low-voltage area (LVA) (area with <0.5 mV bipolar voltage), LA activation time (interval from first LA activation to wavefront collision at lateral wall), regional mean voltage, regional mean wave propagation velocity, and slow conduction area (area with <0.3-m/s wave propagation velocity) were quantitatively analyzed.

RESULTS

Under the rapid PCL, the total LVA was significantly increased (7.6 ± 9.5 vs. 6.7 ± 7.6 cm2, p = 0.031), especially in patients with a ≥10 cm2 LVA on the baseline PCL map (21.5 ± 9.1 vs. 18.1 ± 6.5 cm2, p = 0.013). The LA activation time was also prolonged (87.9 ± 16.2 vs. 84.0 ± 14.0 ms, p < 0.0001). Although the rapid PCL did not decrease the regional mean voltage, it significantly decreased the regional mean wave propagation velocity and increased the slow conduction area in all measured regions.

CONCLUSION

LVA and slow conduction area can be emphasized by rapid PCL LA mapping. There may be poor validity in using these areas as absolute atrial fibrillation substrates without considering the PCL-dependent changes.

Extensive ablation for persistent atrial fibrillation patients with mitral regurgitation: Insights from the EARNEST-PVI prospective randomized trial

BACKGROUND

Extensive ablation in addition to pulmonary vein isolation (PVI) in patients with persistent atrial fibrillation (AF) has not yielded consistent results, indicating diversity in their efficacy. Mitral regurgitation (MR) associated with AF may indicate a higher prevalence of arrhythmogenic substrate, suggesting potential benefits of extensive ablation for these patients.

METHODS

This post-hoc analysis of the EARNEST-PVI trial compared PVI alone versus an extensive ablation strategy (PVI-plus) in persistent AF patients, stratified by MR presence. The primary endpoint of the study was the recurrence of AF. The secondary endpoints included death, cerebral infarction, and procedure-related complications.

RESULTS

The trial included 495 eligible patients divided into MR and non-MR groups. The MR group consisted of 192 patients (89 in the PVI-alone arm and 103 in the PVI-plus arm), while the non-MR group had 303 patients (158 in the PVI-alone arm and 145 in the PVI-plus arm). In the non-MR group, recurrence rates were similar between PVI-alone and PVI-plus arms (Log-rank P = 0.47, Hazard ratio = 0.85 [95%CI: 0.54-1.33], P = 0.472). However, in the MR group, PVI-plus was significantly more effective in preventing AF recurrence (Log-rank P = 0.0014, Hazard ratio = 0.40 [95%CI: 0.22-0.72], P = 0.0021). No significant differences were observed in secondary endpoints between the two arms.

CONCLUSIONS

For persistent AF patients with mild or greater MR, receiving PVI-plus was superior to PVI-alone in preventing AF recurrence. Conversely, for patients without MR, the effectiveness of extensive ablation was not demonstrated. These findings suggest tailoring ablation strategies based on MR presence can lead to better outcomes in AF management.

Left atrial low voltage areas and heart failure in patients with atrial fibrillation: Implication of the atrial myopathy

AIMS

Atrial fibrillation (AF) and heart failure (HF) affect each other and are often co-morbid. The fact that HF development is not uncommon even after ablation suggests that we need a deeper understanding of the pathology of these conditions. Atrial myocardial degeneration is an underlying factor in AF patients and may be associated with HF development after ablation. This study aimed to investigate the impact of low-voltage areas (LVAs) on HF prognosis after AF ablation.

METHODS AND RESULTS

This observational study included 1481 consecutive patients undergoing initial ablation for AF. Left atrial LVAs were defined as regions with a bipolar peak-to-peak voltage of <0.50 mV. Patients were divided into three groups: no LVA (LVA size indexed to body surface area <3 cm2/m2, n = 1129), small LVA (3-10 cm2/m2, n = 217), and extensive LVA (≥10 cm2/m2, n = 135). A composite endpoint of HF hospitalization or death occurred more frequently in patients with larger LVAs (3.3% vs. 6.5% vs. 13.3%, P < 0.0001) during the 3-year follow up period. The extent of LVAs was independently related to the risk of the composite endpoint with an adjusted hazard ratio of 1.55 (95% confidence interval, 1.16-2.10) for each additional step of LVA classification (P = 0.003).

CONCLUSIONS

LVA presence and its extent were associated with frequent HF hospitalization and death. Underlying atrial myopathy appears to define a poor HF prognosis after AF ablation.

Electrocardiogram prediction of atrial fibrillation risk after stroke: A protocol for systematic review and meta-analysis

BACKGROUND

Atrial fibrillation (AF) is one of the most common clinical arrhythmias. This study aims to predict the risk of post-stroke AF through electrocardiographic changes in sinus rhythm.

METHODS

We searched the MEDLINE (PubMed) and EMBASE databases to identify relevant research articles published until August 2023. Prioritized items from systematic reviews and meta-analyses were screened, and data related to AF detection rate were extracted. A meta-analysis using a random-effects model was conducted for data synthesis and analysis.

RESULTS

A total of 32 studies involving electrocardiograms (ECG) were included, with a total analysis population of 330,284 individuals. Among them, 16,662 individuals (ECG abnormal group) developed AF, while 313,622 individuals (ECG normal group) did not. ECG patterns included terminal P-wave terminal force V1, interatrial block (IAB), advanced interatrial block, abnormal P-wave axis, pulse rate prolongation, and atrial premature complexes. Overall, 15,762 patients experienced AF during the study period (4.77%). In the ECG abnormal group, the proportion was 14.21% (2367/16,662), while in the control group (ECG normal group), the proportion was 4.27% (13,395/313,622). The pooled risk ratio for developing AF was 2.45 (95% confidence interval [CI]: 2.02-2.98, P < .001), with heterogeneity (I2) of 95%. The risk ratio values of alAB, P-wave terminal force V1, interatrial block, abnormal P-wave axis, pulse rate prolongation and atrial premature complexes were 4.12 (95% CI, 2.99-5.66), 1.47 (95% CI, 1.19-1.82), 2.54 (95% CI, 1.83-3.52), 1.70 (95% CI, 0.98-2.97), 2.65 (95% CI, 1.88-3.72), 3.79 (95% CI, 2.12-6.76), respectively.

CONCLUSION

There is a significant correlation between ECG patterns and the occurrence of AF. The alAB exhibited the highest level of predictability for the occurrence of AF. These indicators support their use as screening tools to identify high-risk individuals who may benefit from further examinations or empirical anticoagulation therapy following stroke.

Prognostic impact of atrial cardiomyopathy: Long-term follow-up of patients with and without low-voltage areas following atrial fibrillation ablation

BACKGROUND

Atrial cardiomyopathy is known as an underlying pathophysiological factor in the majority of patients with atrial fibrillation (AF). Left atrial low-voltage areas (LVAs) are reported to coincide with fibrosis and likely represent atrial cardiomyopathy.

OBJECTIVE

The purpose of this study was to delineate differences in the long-term prognosis of patients stratified by the size of LVAs.

METHODS

This observational study included 1488 consecutive patients undergoing initial ablation for AF. LVAs were defined as regions with a bipolar peak-to-peak voltage <0.50 mV. The total study population was divided into 3 groups stratified by LVA size: patients with no LVAs (n = 1136); those with small (<20 cm2) LVAs (n = 250) LVAs; and those with extensive (≥20 cm2) LVAs (n = 102). Composite endpoints of death, heart failure, and stroke were followed for up to 5 years.

RESULTS

Composite endpoints developed in 105 of 1488 patients (7.1%), and AF recurrence occurred in 410 (27.6%). Composite endpoints developed more frequently in the order of patients with extensive LVAs (19.1%), small LVAs (10.8%), and no LVAs (5.1%) (P for trend <.0001). Multivariable analysis revealed that LVA presence was independently associated with higher incidence of composite endpoints, irrespective of AF recurrence (modified hazard ratio 1.73; 95% confidence interval 1.13-2.64; P = .011) CONCLUSION: LVA presence and its extent both were associated with poor long-term composite endpoints of death, heart failure, and stroke, irrespective of AF recurrence or other confounders. Underlying atrial cardiomyopathy seems to define a poor prognosis after AF ablation.

Evaluation of the effectiveness and safety of a novel substrate-based radiofrequency ablation for persistent atrial fibrillation: a prospective, randomised, parallel-controlled, single-blinded study protocol

INTRODUCTION

Pulmonary vein isolation (PVI) is the cornerstone of radiofrequency (RF) ablation for atrial fibrillation (AF). However, a single ablation strategy does not always achieve the desired therapeutic effect in all patients with persistent AF, and individualised strategies are required for different clinical characteristics.

METHODS AND ANALYSIS

This study aimed to determine the optimal catheter ablation strategy for persistent AF by comparing the efficacy of PVI and BCXL (BC: big circles encircling pulmonary vein isolation; XL: unfixed number of lines based on the left atrial substrate). The BCXL-AF study (clinical trial no. ChiCTR2200067081) was designed as a prospective, randomised, parallel-controlled, single-blinded clinical trial. Overall, 400 patients with persistent AF were randomised in a 1:1 ratio into PVI-only and BCXL-individualised ablation groups. Patients randomised to the individualised ablation group will be further categorised into risk strata according to their clinical condition using the actual ablation method determined by the strata. Seven postoperative visits were conducted from discharge to 24 months of age. The primary observation endpoint will be the incidence of atrial tachyarrhythmia (including AF, atrial flutter and atrial tachycardia with a duration of ≥30 s) without using antiarrhythmic drugs after a blank period of 3 months following a single ablation procedure. The BCXL-AF study will assess an optimal approach for persistent AF RF ablation and evaluate the effectiveness of individualised RF ablation strategies in reducing the recurrence rate of AF.

ETHICS AND DISSEMINATION

The study protocol was reviewed, and ethical approval was obtained from the Army Medical University Human Ethics Committee (approval number: 2022-484-01). All the participants provided written informed consent. This study was conducted according to the principles of the Declaration of Helsinki and its amendments. The results of this study will be disseminated through manuscript publication and conference presentations.

TRIAL REGISTRATION NUMBER

ChiCTR2200067081.

Clinical impact of left atrial remodeling pattern in patients with atrial fibrillation: Comparison of volumetric, electrical, and combined remodeling

INTRODUCTION

Atrial fibrillation (AF) is accompanied by various types of remodeling, including volumetric enlargement and histological degeneration. Electrical remodeling reportedly reflects histological degeneration.

PURPOSE

To clarify the differences in determinants and clinical impacts among types of remodeling.

METHODS

This observational study included 1118 consecutive patients undergoing initial ablation for AF. Patients were divided into four groups: minimal remodeling (left atrial volume index [LAVI] < mean value and no low-voltage area [LVA], n = 477); volumetric remodeling (LAVI ≥ mean value and no LVA, n = 361); electrical remodeling (LAVI < mean value and LVA presence, n = 96); and combined remodeling (LAVI ≥ mean value and LVA presence, n = 184). AF recurrence and other clinical outcomes were followed up for 2 and 5 years, respectively.

RESULTS

Major determinants of each remodeling pattern were high age for electrical (odds ratio = 2.32, 95% confidence interval = 1.68-3.25) and combined remodeling (2.57, 1.88-3.49); female for electrical (3.85, 2.21-6.71) and combined remodeling (4.92, 2.90-8.25); persistent AF for combined remodeling (7.09, 3.75-13.4); and heart failure for volumetric (1.71, 1.51-2.53) and combined remodeling (2.21, 1.30-3.75). Recurrence rate after initial ablation increased in the order of minimal remodeling (20.1%), volumetric (27.4%) or electrical remodeling (36.5%), and combined remodeling (50.0%, p < .0001). A composite endpoint of heart failure, stroke, and death occurred in the order of minimal (3.4%), volumetric (7.5%) or electrical (8.3%), and combined remodeling (15.2%, p < .0001).

CONCLUSION

Volumetric, electrical, and combined remodeling were each associated with a unique patient background, and defined rhythm and other clinical outcomes.

Recurrence as isthmus-related atrial tachycardia: A cautionary point of low-voltage area homogenization of persistent atrial fibrillation

A 66-year-old female underwent persistent atrial fibrillation ablation. After pulmonary vein isolation and homogenization of low-voltage areas (LVAs), atrial tachycardia (AT) was not induced at the first session; however, it recurred one year after the procedure. During the second session, the extensive LVAs were distributed in the same area of the left atrial anterior wall and expanded possibly due to the previous LVA homogenization. The activation map revealed a macroreentrant AT circuit with the critical isthmus between the isolated right superior pulmonary vein and homogenized LVAs. Although the Ripple map algorithm failed to visualize dynamic bars, extremely low voltage and fractionated potentials (amplitude, 0.04 mV) were observed at the isthmus. Currently, there are various procedural endpoints of LVA-guided ablation (e.g. local electrogram reduction > 50 % or <0.1 mV in amplitude). In this case, incomplete transmural lesions may have led to slow conduction, which could have become an AT substrate. In cases with extensive LVAs on the left atrial anterior wall, eliminating any potential channels may be important for preventing future iatrogenic ATs. LVA-guided ablation should be performed on an individual basis, considering the potential benefits and harms based on the extent and location of LVAs.

Learning objective

Currently, the procedural endpoint of low-voltage area (LVA)-guided ablation varies across studies. Because any low-voltage potentials, except scars, can cause slow conduction, LVA-guided ablation with an endpoint of local electrogram voltage reduction can unintentionally generate an iatrogenic slow conduction isthmus. LVA-guided ablation should be individually performed, considering the potential benefits and harms based on the extent and location of LVAs.

Gender Differences in Atrial Fibrosis and Cardiomyopathy Assessed by Left Atrial Low-Voltage Areas During Catheter Ablation of Atrial Fibrillation

Atrial myocardial degeneration predisposes to atrial fibrillation (AF), ischemic stroke, and heart failure. Studies suggest the presence of gender differences in atrial myocardial degeneration. This study aimed to delineate gender differences in the prevalence, predictors, and prognostic impact of left atrial low-voltage areas (LVAs). This observational study included 1,488 consecutive patients who underwent initial ablation for AF. Voltage mapping was performed after pulmonary vein isolation during sinus rhythm. LVAs were defined as regions where bipolar peak-to-peak voltage was <0.50 mV. LVA prevalence was higher in women (38.7%) than in men (16.0%). High age, persistent form of AF, diabetes mellitus, and a large left atrium were shown to be common predictors in both gender categories. Heart failure and history of stroke/thromboembolic events were men-specific predictors of LVA existence. Women experienced more AF recurrence than men (31.1% vs 25.7%, p = 0.027). LVA existence was significantly associated with increased AF recurrence in each gender category, with a respective hazard ratio, 95% confidence interval, and p value of 2.45, 1.87 to 3.22, and <0.0001 in men and 1.82, 1.33 to 2.49, and <0.0001 in women. In conclusion, LVA was more frequent in women than men, and predicted frequent AF recurrence irrespective of gender category.

Long-Term Impact of Additional Ablation After Pulmonary Vein Isolation: Results From EARNEST-PVI Trial

Background An optimal strategy for left atrial ablation in addition to pulmonary vein isolation (PVI) in patients with persistent atrial fibrillation (AF) has not been determined. Methods and Results We conducted an extended follow-up of the multicenter randomized controlled EARNEST-PVI (Efficacy of Pulmonary Vein Isolation Alone in Patients With Persistent Atrial Fibrillation) trial, which compared 12-month rhythm outcomes in patients with persistent AF between patients randomized to a PVI-alone strategy (n=248) or PVI-plus strategy (n=248; PVI followed by left atrial additional ablation, including linear ablation or ablation targeting areas with complex fractionated electrograms). The present study extended the follow-up period to 3 years after enrollment. Outcomes were compared not only between randomly allocated groups but also between on-treatment groups categorized by actually created ablation lesions. Recurrence rate of AF or atrial tachycardia (AT) was lower in the randomly allocated to PVI-plus group than the PVI-alone group (29.0% versus 37.5%, P=0.036). On-treatment analysis revealed that patients with PVI+linear ablation (n=205) demonstrated a lower AF/AT recurrence rate than those with PVI only (26.3% versus 37.8%, P=0.007). In contrast, patients with PVI+complex fractionated electrograms ablation (n=37) had an AF/AT recurrence rate comparable to that of patients with PVI only (40.5% versus 37.8%, P=0.76). At second ablation in 126 patients with AF/AT recurrence, ATs excluding common atrial flutter were more frequent in patients with PVI+linear ablation than in those with PVI only (32.6% versus 5.7%, P<0.0001). Conclusions Left atrial ablation in addition to PVI was efficacious during 3-year follow-up. Linear ablation was superior to other ablation strategies but may increase iatrogenic ATs. Registration URL: http://www.umin.ac.jp/ctr/index-j.htm; Unique identifier: UMIN000019449.

Clinical and Structural Factors Affecting Ablation Outcomes in Atrial Fibrillation Patients - A Review

Catheter ablation is an effective and durable treatment option for patients with atrial fibrillation (AF). Ablation outcomes vary widely, with optimal results in patients with paroxysmal AF and diminishing results in patients with persistent or long-standing persistent AF. A number of clinical factors including obesity, hypertension, diabetes, obstructive sleep apnea, and alcohol use contribute to AF recurrence following ablation, likely through modulation of the atrial electroanatomic substrate. In this article, we review the clinical risk factors and the electro-anatomic features that contribute to AF recurrence in patients undergoing ablation for AF.

Pulmonary vein isolation alone versus pulmonary vein isolation with additional extensive ablation for paroxysmal and persistent atrial fibrillation

Background

The value of additional ablation beyond pulmonary vein isolation for atrial fibrillation (AF) ablation is unclear, especially for persistent AF. It is uncertain whether substrate modification with additional extensive ablation improves outcomes. We reviewed our experience to determine whether pulmonary vein isolation with additional extensive ablation (PVIEA) improves outcomes compared to pulmonary vein isolation alone (PVIA) for AF ablation.

Methods

Consecutive cases of patients with PVIA versus PVIEA were compared between September 9, 2013 and December 12, 2020. Procedural data collected include radiofrequency ablation delivery time (RADT) and arrhythmia inducibility. Clinical data collected include sinus rhythm maintenance post-procedure.

Results

A total of 235 patients were studied (67 PVIA and 168 PVIEA). RADT was shorter when comparing ablation with PVIA versus PVIEA (32 vs. 40 min; p = .04). More arrhythmias were inducible with PVIEA (p < .01). There was no difference in sinus rhythm maintenance by Kaplan-Meier survival analysis (log-rank test p = .75), after 3 or 12 months between groups overall, and when stratified by AF type (paroxysmal and persistent), left atrial volume, CHA2DS2-VASc score, left ventricular ejection fraction, or catheter ablation setting (high-power short-duration, standard-power standard-duration, temperature-controlled non-contact-force).

Conclusion

AF ablation with PVIA or PVIEA produces similar sinus rhythm maintenance overall and when stratified by catheter setting and AF type. PVIA reduced procedure times and less arrhythmias were inducible post-ablation.

Low-voltage area substrate modification for atrial fibrillation ablation: a systematic review and meta-analysis of clinical trials

AIMS

The value of additional ablation beyond pulmonary vein isolation for atrial fibrillation (AF) ablation is unclear, especially for persistent AF. The optimal target for substrate modification to improve outcomes is uncertain. We investigate the utility of low-voltage area (LVA) substrate modification in patients undergoing catheter ablation for AF.

METHODS

This meta-analysis was reported according to the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines. Medline, Scopus and Cochrane Central Register of Controlled Trials were systematically searched to identify relevant studies. Risk of bias was assessed using the Cochrane risk of bias tool. Only randomized studies were included. AF patients who underwent catheter ablation with voltage-guided substrate modification targeting LVA (LVA group) vs. conventional ablation approaches not targeting LVA (non-LVA group) were compared.

RESULTS

Four studies comprising 539 patients were included (36% female). Freedom from arrhythmia (FFA) in patients with persistent AF was greater in the LVA group [risk ratio (RR) 1.30; 95% confidence interval (CI) 1.03-1.64]. There was no difference in FFA in patients with paroxysmal AF between groups (RR 1.30; 95% CI 0.89-1.91). There was no difference in total procedural time (mean difference -17.54 min; 95% CI -64.37 to 29.28 min) or total ablation time (mean difference -36.17 min; 95% CI -93.69 to 21.35 min) in all included patients regardless of AF type between groups. There was no difference in periprocedural complications between groups in all included patients regardless of AF type (RR 0.93; 95% CI 0.22-3.82).

CONCLUSION

This meta-analysis demonstrates improved FFA in persistent AF patients who underwent voltage-guided substrate modification targeting LVA.