Histological validation of atrial structural remodelling in patients with atrial fibrillation

Efficacy and limitation of nonparoxysmal atrial fibrillation ablation in patients with heart failure with preserved ejection fraction

INTRODUCTION

Catheter ablation for atrial fibrillation (AF) reduces heart failure (HF) hospitalization in patients with HF with preserved ejection fraction (HFpEF). However, the long-term outcomes and subclinical HF after nonparoxysmal AF ablation in HFpEF patients have not been fully evaluated.

METHODS AND RESULTS

One-hundred-ninety nonparoxysmal AF patients with left ventricular ejection fraction ≥50% who underwent first-time AF ablation were studied. HFpEF was diagnosed from a history of congestive HF and/or combined criteria of N-terminal pro-brain natriuretic peptide (NT-proBNP) concentration and transthoracic echocardiogram parameters, including average septal-lateral E/e' and tricuspid regurgitation peak velocity. Ninety-five patients with HFpEF (HFpEF group) were compared with 95 patients without HF (CNT group). Low voltage area (LVA) was defined as an area with a bipolar electrogram of <0.5 mV covering >5% of the total left atrial surface. The primary endpoint was a composite of death from any cause or hospitalization for worsening HF. The secondary endpoint was subclinical HFpEF defined from NT-proBNP concentration and average septal-lateral E/e' or tricuspid regurgitation peak velocity at 6-12 months after the procedure irrespective of the rhythm. Kaplan-Meier curves showed that the primary composite endpoint did not differ between the two groups (mean follow-up period 707 ± 75 days, log-rank p = 0.5330). However, significantly more patients in the HFpEF group reached the secondary endpoint (42 [44%] vs. 13 [14%], p < 0.0001). Multivariate analysis revealed that a high preablation NT-proBNP (odds ratio [OR] 1.001, 95% confidence interval [CI] 1.001-1.002, p = 0.0040) and the existence of LVA (OR 5.983, 95% CI 1.463-31.768, p = 0.0194) independently predicted the secondary endpoint in HFpEF patients.

CONCLUSION

After nonparoxysmal AF ablation, mortality of HFpEF patients was not inferior compared to patients without coexisting HF. However, subclinical HF occasionally persisted especially in HFpEF patients with a high preprocedure NT-proBNP concentration and LVA.

Clinical relevance of left atrial structural remodeling and non-pulmonary vein foci in atrial fibrillation

BACKGROUND

The mechanistic role of left atrial (LA) structural remodeling as a non-pulmonary vein (PV) trigger in the initiation of atrial fibrillation (AF) remains uncertain. This study is aimed at prospectively evaluating the association between non-PV triggers and LA structural remodeling.

METHODS

A total of 517 patients undergoing catheter ablation for AF were included. After PV isolation, a standardized protocol was implemented to reveal non-PV triggers, which included burst pacing into AF followed by cardioversion during isoproterenol infusion. If pacing-induced atrial tachycardia (AT) was observed, mapping and catheter ablation were performed.

RESULTS

The mean percentage of LA low-voltage area (LVA) < 0.5 mV incrementally increased during right atrial pacing among the no induction (n = 470), AF (n = 21), and AT (n = 26) groups (2.6 ± 5.7%, 5.5 ± 6.4%, and 18.0 ± 21.5%, respectively; P < 0.001). In the AF induction group, non-PV foci originated from the left atrium in 13 of 25 foci (52%), and 8 of 13 LA non-PV foci (62%) were located in the septal region. All except 1 focus originated from the non-LVA < 0.5 mV (8%), but 8 of the 13 LA foci originated from the LVA < 1.0 mV (62%). There were no differences in AF recurrence among the groups (log-rank, P = 0.160).

CONCLUSION

The majority of non-PV foci in the LA originated outside regions with advanced structural remodeling, thus suggesting the limited effectiveness of adjunctive ablation guided by the LVA < 0.5 mV during sinus rhythm in eliminating non-PV triggers.

Novel Method for Risk Stratification of Major Adverse Clinical Events Using Pre- and Post-Ablation Left Atrial Volume Index in Patients With Persistent Atrial Fibrillation

Background

The relationship between changes in the left atrial volume index (LAVI) post-catheter ablation (CA) and long-term prognostic events in patients with persistent atrial fibrillation (AF) remains unclear. We evaluated the incidence of major adverse clinical events (MACE), including all-cause death, unplanned heart failure hospitalization, and unplanned cardiovascular hospitalization using pre- and post-CA LAVI.

Methods and Results

We collected data retrospectively from 150 patients with persistent AF who underwent their first CA. LAVI was calculated during preprocedural echocardiography under AF rhythm (pre-CA LAVI) and 3 months post-CA under sinus rhythm (post-CA LAVI). The cumulative incidence of MACE was compared among 3 subgroups based on the cutoff values of pre-CA (45.5 mL/m2) and post-CA (46.5 mL/m2; both determined using the c-statistic) LAVI. The subgroup of a pre-CA LAVI >45.5 mL/m2 with a post-CA LAVI >46.5 mL/m2 (n=45) had a significantly higher MACE incidence compared with other subgroups (P=0.002). Multivariate analysis identified this subgroup as independently at higher risk for MACE. The subgroup of a pre-CA LAVI >45.5 mL/m2 with a post-CA LAVI ≤46.5 mL/m2 (n=49) had an incidence comparable with those with pre-CA LAVI ≤45.5 mL/m2 (n=56) and exhibited a significantly greater reduction in LAVI than other subgroups did (P<0.001).

Conclusions

Combining pre-CA and post-CA LAVIs is valuable in stratifying long-term MACE development risk following CA.

Comprehensive review of pulmonary vein stenosis post-atrial fibrillation ablation: diagnosis, management, and prognosis

Pulmonary vein stenosis (PVS) can occasionally occur in the follow-up after pulmonary vein isolation (PVI) for atrial fibrillation (AF). During PVI, ablation is performed at the PV ostium or distal part, leading to tissue damage. This damage can result in fibrosis of the necrotic myocardium, proliferation, and thickening of the vascular intima, as well as thrombus formation, further advancing PVS. Mild-to-moderate PVS often remains asymptomatic, but severe PVS can cause symptoms, such as dyspnea, cough, fatigue, decreased exercise tolerance, chest pain, and hemoptysis. These symptoms are due to pulmonary hypertension and pulmonary infarction. Imaging evaluations such as contrast-enhanced computed tomography are essential for diagnosing PVS. Early suspicion and detection are necessary, as underdiagnosis can lead to inappropriate treatment, disease progression, and poor outcomes. The long-term prognosis of PVS remains unclear, particularly regarding the impact of mild-to-moderate PVS over time. PVS treatment focuses on symptom management, with no established definitive solutions. For severe PVS, transcatheter PV angioplasty is performed, though the risk of restenosis remains high. Restenosis and reintervention rates have improved with stent implantation compared with balloon angioplasty. The role of subsequent antiplatelet therapy remains uncertain. Dedicated evaluation is essential for accurate diagnosis and appropriate management to avoid significant long-term impacts on patient outcomes.

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.

Left Atrial Low-Voltage Zone Assessment and Voltage-Guided Ablation Outcome in Patients With Atrial Fibrillation-Induced Tachycardiomyopathy

BACKGROUND

Persistent atrial fibrillation (AF) patients with tachycardia-induced cardiomyopathy (TIC) undergoing catheter ablation have similar or even better outcomes than patients without TIC. Data regarding atrial substrate remodeling are scarce in cases of TIC. We assessed regional distribution of left atrial (LA) bipolar voltage, the extent of low-voltage zones (LVZs), and outcomes of voltage-guided ablation in AF patients with and without TIC.

METHODS AND RESULTS

In all, 139 patients with persistent AF presenting for a first voltage-guided catheter ablation were enrolled, 61 with TIC and 78 with structurally normal hearts. LA voltage maps were obtained using a 3-dimensional electroanatomical mapping system in sinus rhythm. LVZ was defined as <0.5 mV. Compared with non-TIC patients, TIC patients had a lower indexed LA volume (median [interquartile range] 58.6 [50.6-68.7] vs. 63.4 [60.1-76.1] mL/m2; P<0.01) and higher LA voltage (2.3 [1.5-2.8] vs. 1.7 [1-2.6] mV; P=0.02). LVZs were less frequently found in patients with than without TIC (8 [13.1%] vs. 30 [39%]; P<0.01). There was no significant difference in atrial tachyarrhythmia (AT)-free survival rate over a 36-month follow-up between the 2 groups (log-rank test, P=0.176). No predictor of AT recurrence was identified.

CONCLUSIONS

TIC patients exhibit less LA substrate remodeling with a smaller LA volume, higher bipolar voltage, and fewer LVZs than non-TIC patients. They have a similar favorable outcome after a single procedure.

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

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

Atrial cardiomyopathy revisited-evolution of a concept: a clinical consensus statement of the European Heart Rhythm Association (EHRA) of the ESC, the Heart Rhythm Society (HRS), the Asian Pacific Heart Rhythm Society (APHRS), and the Latin American Heart Rhythm Society (LAHRS)

AIMS

The concept of "atrial cardiomyopathy" (AtCM) had been percolating through the literature since its first mention in 1972. Since then, publications using the term were sporadic until the decision was made to convene an expert working group with representation from four multinational arrhythmia organizations to prepare a consensus document on atrial cardiomyopathy in 2016 (EHRA/HRS/APHRS/SOLAECE expert consensus on atrial cardiomyopathies: definition, characterization, and clinical implication). Subsequently, publications on AtCM have increased progressively.

METHODS AND RESULTS

The present consensus document elaborates the 2016 AtCM document further to implement a simple AtCM staging system (AtCM stages 1-3) by integrating biomarkers, atrial geometry, and electrophysiological changes. However, the proposed AtCM staging needs clinical validation. Importantly, it is clearly stated that the presence of AtCM might serve as a substrate for the development of atrial fibrillation (AF) and AF may accelerates AtCM substantially, but AtCM per se needs to be viewed as a separate entity.

CONCLUSION

Thus, the present document serves as a clinical consensus statement of the European Heart Rhythm Association (EHRA) of the ESC, the Heart Rhythm Society (HRS), the Asian Pacific Heart Rhythm Society (APHRS), and the Latin American Heart Rhythm Society (LAHRS) to contribute to the evolution of the AtCM concept.

Prognostic value of left atrial reverse remodelling in patients hospitalized with acute decompensated heart failure

AIMS

Left atrial (LA) volume index (LAVI) in chronic heart failure (HF) predicts cardiovascular outcomes. However, the association between LAVI reduction during acute decompensated HF (ADHF) and its prognostic potential is limited. We hypothesized that LA reverse remodelling (LARR) after ADHF therapy would be associated with better clinical outcomes.

METHODS

This retrospective study analysed clinical outcomes and the LAVI reduction rate of 363 out of 861 patients hospitalized for ADHF who underwent two-point echocardiography at admission and discharge between January 2015 and December 2019. The mean age was 74.3 ± 13.6 years, and the mean ejection fraction (EF) was 38.9 ± 15.2%. The follow-up echocardiogram was performed 13.0 [9.5, 20] days after admission. As the median LAVI reduction rate was 7.02%, the LARR was defined as an LAVI reduction rate >7%.

RESULTS

During the 34.0 ± 20.2 months of follow-up, 117 patients (32.2%) reached the primary endpoint defined as cardiovascular death and rehospitalization for ADHF. Kaplan-Meier survival analysis showed that patients with LARR had a better prognosis. Multivariate analysis indicated that LARR was an independent predictor of cardiovascular events. Similar findings were observed in the subgroup analyses of patients with persistent/permanent atrial fibrillation and those with non-HF with reduced EF. Among patients who were brain natriuretic peptide (BNP) responders, defined as a relative reduction of >70% in BNP from admission to discharge, non-LARR was observed in 41.6%. BNP responders without LARR experienced worse prognoses.

CONCLUSIONS

LARR in the early vulnerable phase after hospitalization for ADHF was associated with better long-term clinical outcomes.

Revolutionizing tracheal reconstruction: innovations in vascularized composite allograft transplantation

Tracheal defects, particularly those extending over long segments, present substantial challenges in reconstructive surgery due to complications in vascularization and integration with host tissues. Traditional methods, such as extended tracheostomies and alloplastic stents, often result in significant morbidity due to mucus plugging and mechanical erosion. Recent advances in vascularized composite allograft (VCA) transplantation have opened new avenues for effective tracheal reconstruction. This article reviews the evolution of tracheal reconstruction techniques, focusing on the shift from non-vascularized approaches to innovative revascularization methods that enhance graft integration and functionality. Key advancements include indirect revascularization techniques and the integration of regenerative medicine, which have shown promise in overcoming historical barriers to successful tracheal transplantation. Clinical case studies are presented to illustrate the complexities and outcomes of recent tracheal transplantation procedures, highlighting the potential for long-term success through the integration of advanced vascular engineering and immune modulation strategies. Furthermore, the role of chimerism in reducing graft rejection and the implications for future tracheal transplantation and tissue engineering efforts are discussed. This review underscores the transformative potential of VCA in tracheal reconstruction, paving the way for more reliable and effective treatments for extensive tracheal defects.

Identification of potential biomarkers for atrial fibrillation and stable coronary artery disease based on WGCNA and machine algorithms

BACKGROUND

Patients with atrial fibrillation (AF) often have coronary artery disease (CAD), but the biological link between them remains unclear. This study aims to explore the common pathogenesis of AF and CAD and identify common biomarkers.

METHODS

Gene expression profiles for AF and stable CAD were downloaded from the Gene Expression Omnibus database. Overlapping genes related to both diseases were identified using weighted gene co-expression network analysis (WGCNA), followed by functional enrichment analysis. Hub genes were then identified using the machine learning algorithm. Immune cell infiltration and correlations with hub genes were explored, followed by drug predictions. Hub gene expression in AF and CAD patients was validated by real-time qPCR.

RESULTS

We obtained 28 common overlapping genes in AF and stable CAD, mainly enriched in the PI3K-Akt, ECM-receptor interaction, and relaxin signaling pathway. Two hub genes, COL6A3 and FKBP10, were positively correlated with the abundance of MDSC, plasmacytoid dendritic cells, and regulatory T cells in AF and negatively correlated with the abundance of CD56dim natural killer cells in CAD. The AUCs of COL6A3 and FKBP10 were all above or close to 0.7. Drug prediction suggested that collagenase clostridium histolyticum and ocriplasmin, which target COL6A3, may be potential drugs for AF and stable CAD. Additionally, COL6A3 and FKBP10 were upregulated in patients with AF and CAD.

CONCLUSION

COL6A3 and FKBP10 may be key biomarkers for AF and CAD, providing new insights into the diagnosis and treatment of this disease.

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

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

Practical approach for atrial cardiomyopathy characterization in patients with atrial fibrillation

Atrial fibrillation (AF) causes progressive structural and electrical changes in the atria that can be summarized within the general concept of atrial remodeling. In parallel, other clinical characteristics and comorbidities may also affect atrial tissue properties and make the atria susceptible to AF initiation and its long-term persistence. Overall, pathological atrial changes lead to atrial cardiomyopathy with important implications for rhythm control. Although there is general agreement on the role of the atrial substrate for successful rhythm control in AF, the current classification oversimplifies clinical management. The classification uses temporal criteria and does not establish a well-defined strategy to characterize the individual-specific degree of atrial cardiomyopathy. Better characterization of atrial cardiomyopathy may improve the decision-making process on the most appropriate therapeutic option. We review current scientific evidence and propose a practical characterization of the atrial substrate based on 3 evaluation steps starting with a clinical evaluation (step 1), then assess outpatient complementary data (step 2), and finally include information from advanced diagnostic tools (step 3). The information from each of the steps or a combination thereof can be used to classify AF patients in 4 stages of atrial cardiomyopathy, which we also use to estimate the success on effective rhythm control.

Impact of left atrial strain on clinical outcomes in patients with permanent pacemaker implantation

AIMS

This study aimed to investigate the clinical impact of pre-procedural left atrial strain (LAS) in patients undergoing permanent pacemaker implantation (PPI).

METHODS AND RESULTS

This single-centre retrospective study enrolled 434 patients who were admitted for transvenous PPI between 2010 and 2020. After excluding patients with persistent atrial fibrillation, PPI for complete atrioventricular block, severe valvular disease, history of open-heart surgery and those without LAS data, 172 patients were analysed. The LAS was measured using commercially available software to calculate the average strain value of the apical four- and two-chamber views before PPI. The primary composite endpoint was hospitalization due to heart failure or cardiovascular death. Cox proportional hazard models were used to evaluate risk factors for the primary composite endpoint. The mean patient age was 78 ± 8 years, and 42% of the patients were men. PPI was performed for sick sinus syndrome in 64% and second-degree atrioventricular block in 36% of the patients. The pre-procedure left atrial reservoir strain (LASr) was 28 ± 11%. The median follow-up period was 4.7 years, and the primary endpoint was observed in 23 (13%) patients. In multivariate Cox proportional risk analysis, LASr was independently associated with the primary composite endpoint (hazard ratio, 1.08 per 1% decrease; 95% confidence interval, 1.02-1.15; P = 0.007). The receiver operating characteristic curve of the LASr for the primary composite endpoint showed a cutoff value of 21% (area under the curve 0.657, P = 0.004). The prognostic impact of LASr was consistent with that of sick sinus syndrome and atrioventricular block.

CONCLUSIONS

A decreased pre-procedure LASr was associated with long-term adverse outcomes after PPI use.

Efficacy and safety of catheter ablation for atrial fibrillation in patients with heart failure with preserved ejection fraction: a systematic review and meta-analysis

Background

Catheter ablation (CA) effectively treats atrial fibrillation (AF) in heart failure (HF) with reduced ejection fraction (HFrEF), improving clinical outcomes. However, its benefits for AF patients with heart failure with preserved ejection fraction (HFpEF) are still unclear.

Methods

We systematically searched PubMed, Embase, Web of Science, the Cochrane Library, and Scopus for studies investigating outcomes of CA in AF patients with HFpEF. Efficacy indicators included freedom from AF and antiarrhythmic drugs (AAD) free AF elimination. Safety indicators comprised total complications, HF admission, all-cause admission, and all-cause mortality. Sixteen studies with 20,796 patients included in our research.

Results

The comprehensive analysis demonstrated that, when comparing CA with medical therapy in HFpEF, no significant differences were observed in terms of HF admissions, all-cause admissions, and all-cause mortality [(OR: 0.42; 95% CI: 0.12-1.51, P = 0.19), (HR: 0.78; 95% CI: 0.48-1.27, P = 0.31), and (OR: 1.10; 95% CI: 0.83-1.44, P = 0.51)], while freedom from AF was significantly higher in CA (OR: 5.88; 95% CI: 2.99-11.54, P < 0.00001). Compared with HFrEF, CA in HFpEF showed similar rates of freedom from AF, AAD-free AF elimination, total complications, and all-cause admission were similar [(OR:0.91; 95% CI: 0.71,1.17, P =0.47), (OR: 0.97; 95% CI: 0.50-1.86, P = 0.93), (OR: 1.27; 95% CI: 0.47-3.41, P = 0.64), (OR: 1.11; 95% CI: 0.72, 1.73; P = 0.63)]. However, CA in HFpEF was associated with lower rates of HF admission and all-cause mortality [(OR: 0.35; 95% CI: 0.20, 0.60; P = 0.0002), (OR: 0.40; 95% CI: 0.18, 0.85; P = 0.02)]. Compared with patients without HF, CA in HFpEF patients exhibited lower rates of AAD-free AF elimination (OR: 0.48; 95% CI: 0.30, 0.75; P = 0.001). However, their rates of freedom from AF and total complications were similar [(OR: 0.70; 95% CI: 0.48, 1.02; P = 0.06), (OR: 0.60; 95% CI: 0.19, 1.90; P = 0.38)].

Conclusion

This meta-analysis conducted provided a comprehensive evaluation of the efficacy and safety of CA in patients with AF and HFpEF. The results suggest that CA may represent a valuable treatment strategy for patients with AF and HFpEF.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/#recordDetails, identifier (CRD42024514169).

Left atrial reservoir strain is a marker of atrial fibrotic remodeling in patients undergoing cardiovascular surgery: Analysis of gene expression

Left atrial strain (LAS) measured by two-dimensional speckle tracking echocardiography (2DSTE) is considered to be a marker of LA structural remodeling, but it remains unsettled. We investigated the potential usefulness and clinical relevance of LAS to detect atrial remodeling including fibrosis by analyzing gene expression in cardiovascular surgery patients. Preoperative 2DSTE was performed in 131 patients (92 patients with sinus rhythm [SR] patients including paroxysmal AF [PAF], 39 atrial fibrillation [AF]) undergoing cardiovascular surgery. Atrial samples were obtained from the left atrial appendages, and mRNA expression level was analyzed by real-time reverse transcription polymerase chain reaction (RT-PCR) in 59 cases (24 PAF, 35 AF). Mean value of left atrial reservoir strain (mLASr) correlated with left atrial volume index (LAVI), and left atrial conduit strain (mLAScd). mLASr also correlated with left atrial contractile strain (mLASct) in SR patients including PAF. mLASr was significantly lower, and LAVI was higher, in the AF group, compared with SR patients including PAF. The expression of COL1A1 mRNA encoding collagen type I α1 significantly increased in AF patients (p = 0.031). mLASr negatively correlated with COL1A1 expression level, and multivariate regression analysis showed that mLASr was an independent predictor of atrial COL1A1 expression level, even after adjusting for age, sex, and BMI. But, neither mLAScd / mLASct nor LAVI (bp) correlated with COL1A1 gene expression. The expression level of COL1A1 mRNA strongly correlated with ECM-related genes (COL3A1, FN1). It also correlated ECM degradation-related genes (MMP2, TIMP1, and TIMP2), pro-fibrogenic cytokines (TGFB1 encoding TGFβ1, END1, PDGFD, CTGF), oxidant stress-related genes (NOX2, NOX4), ACE, inflammation-related genes (NLRP, IL1B, MCP-1), and apoptosis (BAX). Among the fibrosis-related genes examined, univariable regression analysis showed that log (COL1A1) was associated with log (TGFB1) (adjusted R2 = 0.685, p<0.001), log (NOX4) (adjusted R2 = 0.622, p<0.001), log (NOX2) (adjusted R2 = 0.611, p<0.001), suggesting that TGFB1 and NOX4 was the potent independent determinants of COL1A1 expression level. mLASr negatively correlated with the ECM-related genes, and fibrosis-related gene expression level including TGFB1, NOX2, and NLRP3 in PAF patients. PAF patients with low mLASr had higher expression of the fibrosis-related gene expression, compared with those with high mLASr. These results suggest that LASr correlates with atrial COL1A1 gene expression associated with fibrosis-related gene expression. Patients with low LASr exhibit increased atrial fibrosis-related gene expression, even those with PAF, highlighting the utility of LAS as a marker for LA fibrosis in cardiovascular surgery patients.

Structural, Functional, and Electrical Remodeling of the Atria With Reduced Cardiorespiratory Fitness: Implications for AF

BACKGROUND

Reduced cardiorespiratory fitness (CRF) is an independent risk factor for the progression of atrial fibrillation (AF). We hypothesized that reduced CRF is associated with structural, functional, and electrical remodeling of the left atrium.

OBJECTIVES

This study sought to correlate objectively assessed CRF with functional and electrical left atrial (LA) parameters using invasive and noninvasive assessments.

METHODS

Consecutive patients with symptomatic AF undergoing catheter ablation were recruited. CRF was objectively quantified pre-ablation by using cardiopulmonary exercise testing. Using peak oxygen consumption, participants were classified as preserved CRF (>20 mL/kg/min) or reduced CRF (<20 mL/kg/min). LA stiffness was assessed invasively with hemodynamic monitoring and imaging during high-volume LA saline infusion. LA stiffness was calculated as ΔLA diameter/ΔLA pressure over the course of the infusion. LA function was assessed with echocardiographic measures of LA emptying fraction and LA strain. Electrical remodeling was assessed by using high-density electroanatomical maps for LA voltage and conduction.

RESULTS

In total, 100 participants were recruited; 43 had reduced CRF and 57 had preserved CRF. Patients with reduced CRF displayed elevated LA stiffness (P = 0.004), reduced LA emptying fraction (P = 0.006), and reduced LA reservoir strain (P < 0.001). Reduced CRF was also associated with reduced LA voltage (P = 0.039) with greater heterogeneity (P = 0.027) and conduction slowing (P = 0.04) with greater conduction heterogeneity (P = 0.02). On multivariable analysis, peak oxygen consumption was independently associated with LA stiffness (P = 0.003) and LA conduction velocities (P = 0.04).

CONCLUSIONS

Reduced CRF in patients with AF is independently associated with worse LA disease involving functional and electrical changes. Improving CRF may be a target for restoring LA function in AF.

Pulmonary Vein Intervention for Severe Pulmonary Vein Stenosis After Atrial Fibrillation Ablation - A Retrospective Cohort Study

BACKGROUND

Pulmonary vein (PV) stenosis (PVS) is a serious complication of atrial fibrillation (AF) ablation. The objective of this study was to describe interventional treatments for PVS after AF ablation and long-term outcomes in Japanese patients.

METHODS AND RESULTS

This multicenter retrospective observational study enrolled 30 patients (26 [87%] male; median age 55 years) with 56 severe PVS lesions from 43 PV interventional procedures. Twenty-seven (90%) patients had symptomatic PVS and 19 (63%) had a history of a single AF ablation. Of the 56 lesions, 41 (73%) were de novo lesions and 15 (27%) were retreated. Thirty-three (59%) lesions were treated with bare metal stents, 14 (25%) were treated with plain balloons, and 9 (16%) were treated with drug-coated balloons. All lesions were successfully treated without any systemic embolic event. Over a median follow-up of 584 days (interquartile range 265-1,165 days), restenosis rates at 1 and 2 years were 35% and 47%, respectively. Multivariate Cox regression analysis revealed devices <7 mm in diameter (hazard ratio [HR] 2.52; 95% confidence interval [CI] 1.04-6.0; P=0.040) and totally occluded lesions (HR 3.33; 95% CI 1.21-9.15; P=0.020) were independent risk factors for restenosis.

CONCLUSIONS

All PVS lesions were successfully enlarged by the PV intervention; however, restenosis developed in approximately half the lesions within 2 years.

Association between psoriasis and atrial fibrillation: A Systematic review and meta-analysis

INTRODUCTION

Psoriasis is a prevalent inflammatory skin condition characterized by erythematous plaques with scaling. Recent research has demonstrated an increased risk of cardiovascular diseases in patients with psoriasis; however, current evidence on atrial fibrillation (AF) risk in psoriasis is limited.

MATERIALS AND METHODS

A systematic literature search was performed on major bibliographic databases to retrieve studies that evaluated AF risk in patients with psoriasis. The DerSimonian and Laird random effects model was used to pool the hazard ratios (HR) with 95 % confidence intervals (CI). Subgroup analysis was conducted by dividing the patients into mild and severe psoriasis groups. Publication bias was assessed by visual inspection and Egger's regression test. Statistical significance was set at p < 0.05.

RESULTS

Seven studies were included, with 10,974,668 participants (1,94,230 in the psoriasis group and 10,780,439 in the control group). Patients with psoriasis had a significantly higher risk of AF [Pooled HR: 1.28; 95 % CI: 1.20, 1.36; p < 0.00001]. In subgroup analysis, patients with severe psoriasis [HR: 1.32; 95 % CI: 1.23, 1.42; p < 0.00001] demonstrated a slightly higher risk of AF, although statistically insignificant (p = 0.17), than the mild psoriasis group [HR: 1.21; 95 % CI: 1.10, 1.33; p < 0.0001]. Egger's regression test showed no statistically significant publication bias (p = 0.24).

CONCLUSION

Our analysis demonstrated that patients with psoriasis are at a significantly higher risk of AF and hence should be closely monitored for AF. Further large-scale and multicenter randomized trials are warranted to validate the robustness of our findings.

Duration of atrial fibrillation persistence: Implications for recurrence risk after catheter ablation and efficacy of additional substrate ablation

BACKGROUND

The optimal duration of atrial fibrillation (AF) persistence for predicting poor outcomes after catheter ablation of long-standing AF (LsAF) and the best ablation strategy for these patients remain unclear.

OBJECTIVE

We aimed to assess the impact of the duration of AF persistence on outcomes after catheter ablation of AF.

METHODS

We analyzed the Efficacy of Pulmonary Vein Isolation Alone in Patients with Persistent Atrial Fibrillation (EARNEST-PVI) trial data comparing pulmonary vein isolation (PVI) alone (PVI-alone) with additional linear ablation or defragmentation (PVI-plus) in persistent AF (PerAF). Patients who received catheter ablation by contact force-sensing catheter were enrolled in the study. In patients with LsAF, the optimal cutoff duration of AF persistence was evaluated. With use of the threshold, patients with LsAF were divided into 2 groups and compared with PerAF <1 year for arrhythmia-free survival after a 3-month blanking period.

RESULTS

The optimal cutoff duration was 2.4 years. Of 458 patients, arrhythmia-free survival rates for LsAF 1-2.4 years were comparable to those of PerAF (hazard ratio [HR], 1.01; 95% CI, 0.67-1.52). However, LsAF >2.4 years had a higher recurrence risk than PerAF (HR, 2.22; 95% CI, 1.42-3.47). In LsAF >2.4 years, the PVI-plus strategy showed advantages over the PVI-alone strategy (HR, 0.36; 95% CI, 0.14-0.89). However, the interaction effect between LsAF 1-2.4 years and LsAF >2.4 years did not reach statistical significance (P = .116).

CONCLUSION

Whereas LsAF 1-2.4 years has similar outcomes to those of PerAF, LsAF >2.4 years was linked to higher arrhythmia recurrence risks. For LsAF >2.4 years, the PVI-plus strategy showed a potential to be superior to the PVI-alone strategy.

Atrial structural remodeling and atrial fibrillation substrate: A histopathological perspective

Atrial fibrillation (AF) substrate progresses with the advancement of atrial structural remodeling, resulting in AF perpetuation and recurrence. Although fibrosis is considered a hallmark of atrial structural remodeling, the histological background has not been fully elucidated because obtaining atrial specimens is difficult, especially in patients not undergoing open-heart surgery. Bipolar voltage reduction evaluated using electroanatomic mapping during AF ablation is considered a surrogate marker for the progression of structural remodeling; however, histological validation is lacking. We developed an intracardiac echocardiography-guided endomyocardial atrial biopsy technique to evaluate atrial structural remodeling in patients undergoing catheter ablation for nonvalvular AF. The histological factors associated with a decrease in bipolar voltage were interstitial fibrosis, as well as an increase in myocardial intercellular space preceding fibrosis, myofibrillar loss, and a decrease in cardiomyocyte nuclear density, which is a surrogate marker for cardiomyocyte density. Cardiomyocyte hypertrophy is closely associated with a decrease in cardiomyocyte nuclear density, suggesting that hypertrophic changes compensate for cardiomyocyte loss. Electron microscopy also revealed that increased intercellular spaces indicated the leakage of plasma components owing to increased vascular permeability. Additionally, amyloid deposition was observed in 4 % of biopsy cases. Only increased intercellular space and interstitial fibrosis were significantly higher for long-standing persistent AF than for paroxysmal AF and associated with recurrence after AF ablation, suggesting that this interstitial remodeling is the AF substrate. An increase in intercellular space that occurs early in AF formation is a therapeutic target for the AF substrate, which prevents irreversible interstitial degeneration due to collagen accumulation. This endomyocardial atrial biopsy technique will allow the collection of atrial tissue from a wide variety of patients and significantly facilitate the elucidation of the mechanisms of atrial cardiomyopathy, structural remodeling, and AF substrates.

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

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

Identification of Atrial Transmural Conduction Inhomogeneity Using Unipolar Electrogram Morphology

(1) Background: Structural remodeling plays an important role in the pathophysiology of atrial fibrillation (AF). It is likely that structural remodeling occurs transmurally, giving rise to electrical endo-epicardial asynchrony (EEA). Recent studies have suggested that areas of EEA may be suitable targets for ablation therapy of AF. We hypothesized that the degree of EEA is more pronounced in areas of transmural conduction block (T-CB) than single-sided CB (SS-CB). This study examined the degree to which SS-CB and T-CB enhance EEA and which specific unipolar potential morphology parameters are predictive for SS-CB or T-CB. (2) Methods: Simultaneous endo-epicardial mapping in the human right atrium was performed in 86 patients. Potential morphology parameters included unipolar potential voltages, low-voltage areas, potential complexity (long double and fractionated potentials: LDPs and FPs), and the duration of fractionation. (3) Results: EEA was mostly affected by the presence of T-CB areas. Lower potential voltages and more LDPs and FPs were observed in T-CB areas compared to SS-CB areas. (4) Conclusion: Areas of T-CB could be most accurately predicted by combining epicardial unipolar potential morphology parameters, including voltages, fractionation, and fractionation duration (AUC = 0.91). If transmural areas of CB indeed play a pivotal role in the pathophysiology of AF, they could theoretically be used as target sites for ablation.

Quantitative analysis of fractionated electrogram area of left atrium during right atrial pacing as an indicator of left atrial electrical remodeling in patients with atrial fibrillation

Background

The clinical significance of left atrial local electrogram fractionation after restoration of sinus rhythm in patients with atrial fibrillation (AF) has not been elucidated.

Methods

We evaluated ultrahigh-resolution maps of the left atrium (LA) during RA pacing acquired after pulmonary vein isolation in 40 patients with AF. The association between low-voltage area (LVA, <0.5 mV), fractionated electrogram area (FEA, the highlighted area with LUMIPOINT™ Complex Activation), the interval from onset of LA activation to wavefront collision at the mitral isthmus (LA activation time), and wave propagation velocity (WPV) was evaluated quantitatively.

Results

The total LVA, total FEA with ≥5.0 peaks or ≥7.0 peaks were 7.0 ± 7.9 cm2, 15.9 ± 12.9 cm2, and 5.2 ± 7.5 cm2, respectively. These areas were predominantly observed in the anteroseptal region. Total LVA, total FEA with ≥5.0 peaks, and total FEA with ≥5.0 peaks in the normal voltage area (NVA: ≥0.5 mV) correlated with LA activation time (R = 0.69, 0.75, and 0.71; each p < .0001). In the anterior wall, these areas correlated with regional mean WPV (R = -0.75, -0.83, and - 0.55; each p < .0001) and the extent of slow conduction area (SCA) with WPV <0.3 m/s (R = 0.89, 0.84, 0.33; p < .0001 for LVA and FEA, p < .05 for FEA located in NVA). The anterior wall FEA with ≥7.0 peaks and that in the NVA showed a better correlation in predicting anterior wall SCA (R = 0.92 and 0.86, each p < .0001).

Conclusion

Quantitative analysis of FEA together with LVA may facilitate the assessment of LA electrical remodeling.

Overcoming Uncertainties in Electrogram-Based Atrial Fibrillation Mapping: A Review

In clinical rhythmology, intracardiac bipolar electrograms (EGMs) play a critical role in investigating the triggers and substrates inducing and perpetuating atrial fibrillation (AF). However, the interpretation of bipolar EGMs is ambiguous due to several aspects of electrodes, mapping algorithms and wave propagation dynamics, so it requires several variables to describe the effects of these uncertainties on EGM analysis. In this narrative review, we critically evaluate the potential impact of such uncertainties on the design of cardiac mapping tools on AF-related substrate characterization. Literature suggest uncertainties are due to several variables, including the wave propagation vector, the wave's incidence angle, inter-electrode spacing, electrode size and shape, and tissue contact. The preprocessing of the EGM signals and mapping density will impact the electro-anatomical representation and the features extracted from the local electrical activities. The superposition of multiple waves further complicates EGM interpretation. The inclusion of these uncertainties is a nontrivial problem but their consideration will yield a better interpretation of the intra-atrial dynamics in local activation patterns. From a translational perspective, this review provides a concise but complete overview of the critical variables for developing more precise cardiac mapping tools.

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.

Personalized biomechanical insights in atrial fibrillation: opportunities & challenges

INTRODUCTION

Atrial fibrillation (AF) is an increasingly prevalent and significant worldwide health problem. Manifested as an irregular atrial electrophysiological activation, it is associated with many serious health complications. AF affects the biomechanical function of the heart as contraction follows the electrical activation, subsequently leading to reduced blood flow. The underlying mechanisms behind AF are not fully understood, but it is known that AF is highly correlated with the presence of atrial fibrosis, and with a manifold increase in risk of stroke.

AREAS COVERED

In this review, we focus on biomechanical aspects in atrial fibrillation, current and emerging use of clinical images, and personalized computational models. We also discuss how these can be used to provide patient-specific care.

EXPERT OPINION

Understanding the connection betweenatrial fibrillation and atrial remodeling might lead to valuable understanding of stroke and heart failure pathophysiology. Established and emerging imaging modalities can bring us closer to this understanding, especially with continued advancements in processing accuracy, reproducibility, and clinical relevance of the associated technologies. Computational models of cardiac electromechanics can be used to glean additional insights on the roles of AF and remodeling in heart function.