Atrial Fibrillation

Atrial remodelling and atrial fibrillation self-sustaining: the role of circulating circDGCR8

AIMS

The prediction of atrial fibrillation (AF) progression and post-ablation recurrence is currently based on empirical estimates, leading to suboptimal predictive accuracy. This study investigates whether atrial remodelling, a key factor in the severity of atrial cardiomyopathy, could serve as a shared substrate influencing both AF progression and recurrence. We aimed to identify circular RNAs (circRNAs) associated with atrial remodelling and to evaluate their ability to predict AF progression and recurrence.

METHODS AND RESULTS

We assessed the differential expression of plasma circRNAs between paroxysmal (PAF) and persistent AF (PsAF) patients using microarray analysis. Selected candidate circRNAs were validated through qPCR following rigorous statistical and bioinformatics analysis. circDGCR8 was consistently found to be up-regulated in PsAF compared with PAF patients. Additionally, circDGCR8 was significantly up-regulated in human atrial fibroblasts treated with angiotensin II (AngII). Gain- and loss-of-function studies suggested that circDGCR8 could promote atrial remodelling at cellular level by enhancing collagen production and fibroblast proliferation. Overexpression of circDGCR8 in human cardiac fibroblasts significantly altered the gene expression spectrum, impacting pathways including IL-17 signalling and TNF signalling. Moreover, circDGCR8 levels were positively correlated with atrial fibrosis, as indicated by increased percentages of low voltage zones. The predictive value of circDGCR8 was evaluated in two cohorts: (i) PAF patients monitored for 36 months with progression to PsAF as the endpoint, and (ii) AF patients who underwent radiofrequency ablation followed for 12 months to assess recurrence. In both cohorts, higher level of circDGCR8 was associated with increased risks of AF progression and post-ablation recurrence.

CONCLUSION

Our results suggest that circDGCR8, associated with atrial remodelling, holds potential as a predictive biomarker for both AF progression and post-ablation recurrence.

Diagnostic biomarkers and immune infiltration profiles common to COVID-19, acute myocardial infarction and acute ischaemic stroke using bioinformatics methods and machine learning

BACKGROUND

COVID-19 is a disease that affects people globally. Beyond affecting the respiratory system, COVID-19 patients are at an elevated risk for both venous and arterial thrombosis. This heightened risk contributes to an increased probability of acute complications, including acute myocardial infarction (AMI) and acute ischemic stroke (AIS). Given the unclear relationship between COVID-19, AMI, and AIS, it is crucial to gain a deeper understanding of their associations and potential molecular mechanisms. This study aims to utilize bioinformatics to analyze gene expression data, identify potential therapeutic targets and biomarkers, and explore the role of immune cells in the disease.

METHODS

This study employed three Gene Expression Omnibus (GEO) datasets for analysis, which included data on COVID-19, AMI and AIS. We performed enrichment analysis on the co-DEGs for these three diseases to clarify gene pathways and functions, and also examined the relationship between co-DEGs and immune infiltration. Machine learning techniques and protein-protein interaction networks (PPI) were used to identify hub genes within the co-DEGs. Finally, we employed a dual validation strategy integrating independent GEO datasets and in vitro experiments with human blood samples to comprehensively assess the reliability of our experimental findings.

RESULTS

We identified 88 co-DEGs associated with COVID-19, AMI and AIS. Enrichment analysis results indicated that co-DEGs were significantly enriched in immune inflammatory responses related to leukocytes and neutrophils. Immune infiltration analysis revealed significant differences in immune cell populations between the disease group and the normal group. Finally, genes selected through machine learning methods included: CLEC4E, S100A12, and IL1R2. Based on the PPI network, the top ten most influential DEGs were identified as MMP9, TLR2, TLR4, ITGAM, S100A12, FCGR1A, CD163, FCER1G, FPR2, and CLEC4D. The integration of the protein-protein interaction (PPI) network with machine learning techniques facilitated the identification of S100A12 as a potential common biomarker for early diagnosis and a therapeutic target for all three diseases. Ultimately, validation of S100A12 showed that it was consistent with our experimental results, confirming its reliability as a biomarker. Moreover, it demonstrated good diagnostic performance for the three diseases.

CONCLUSION

We employed bioinformatics methods and machine learning to investigate common diagnostic biomarkers and immune infiltration characteristics of COVID-19, AMI and AIS. Functional and pathway analyses indicated that the co-DEGs were primarily enriched in immune inflammatory responses related to leukocytes and neutrophils. Through two machine learning approaches and the PPI network, and subsequent validation and evaluation, we identified S100A12 as a potential common therapeutic target and biomarker related to immune response that may influence these three diseases.

Comparative Efficacy and Safety of Low-Dose Direct Oral Anticoagulants Versus Dual Antiplatelet Therapy Following Left Atrial Appendage Occlusion in Patients With Nonvalvular Atrial Fibrillation: A Systematic Review and Meta-Analysis

BACKGROUND

Left atrial appendage occlusion (LAAO) is an alternative to chronic oral anticoagulation (OAT) for stroke prevention in nonvalvular atrial fibrillation (NVAF) patients with contraindications to OAT. Postprocedure antithrombotic therapy (ATT) is essential to reduce the risk of device-related thrombosis (DRT), but the optimal regimen remains uncertain.

AIMS

This study aims to compare the safety and efficacy of low-dose direct oral anticoagulants (DOACs) versus dual antiplatelet therapy (DAPT) following LAAO.

METHODS

A comprehensive search of PubMed, Scopus, Cochrane, and Web of Science was conducted in August 2024. Studies comparing low-dose DOACs and DAPT post-LAAO were included. The primary outcomes were a composite efficacy endpoint (DRT, strokes, and systemic embolism [SE]) and major bleeding events as the safety endpoint. Secondary outcomes included all bleeding events, all-cause mortality, and a composite of efficacy and safety endpoints.

RESULTS

Four studies with 727 patients were included. Low-dose DOACs were associated with lower rates of the primary composite efficacy endpoint compared to DAPT (OR = 0.36; 95% CI [0.16, 0.85], p = 0.01). No significant difference in major bleeding events was observed (OR = 0.36; 95% CI [0.11, 1.18]; p = 0.091; I² = 0%). Compared to DAPT, low-dose DOACs were also associated with lower rates of DRT events (OR = 0.36; 95% CI [0.16, 0.79], p = 0.011).

CONCLUSION

Low-dose DOACs effectively reduce thromboembolic events post-LAAO without increasing bleeding risk. These findings support their use as a viable ATT option, but larger trials are needed to confirm optimal regimens.

Propafenone- vs. amiodarone-associated adverse cardiac outcomes in patients with atrial fibrillation and heart failure

AIMS

Clinical trials have shown an increased risk of death in patients with recent myocardial infarction who received antiarrhythmic drugs such as flecainide, encainide or moricizine, especially in the presence of associated structural heart disease such as cardiac dysfunction. This study aimed to evaluate the safety outcomes of propafenone use in atrial fibrillation patients with heart failure when compared to those of amiodarone use.

METHODS

This population-based cohort study used the National Health Insurance Research Database in Taiwan. Eligible patients were those who had atrial fibrillation or atrial flutter diagnosis, had heart failure diagnosis, and first received propafenone or amiodarone between 2002 and 2018. The primary endpoints were death due to arrhythmia and the composite proarrhythmic outcome, which consisted of sudden cardiac arrest, arrhythmic death, ventricular arrhythmia and implantation of defibrillator.

RESULTS

After propensity score matching, the study cohort consisted of 7235 propafenone and 14 470 amiodarone users. Compared to amiodarone, propafenone was associated with significantly lower risk of the composite proarrhythmic outcome (adjusted hazard ratio: 0.52; 95% confidence interval: 0.42-0.64; P < .001). Propafenone users also had lower risk of death owing to arrhythmia compared to amiodarone users (adjusted hazard ratio: 0.22; 95% confidence interval: 0.08-0.65; P = .006). Subgroup analysis and sensitivity analysis showed similar trends, favouring propafenone.

CONCLUSION

Propafenone was not significantly associated with increased risk of proarrhythmia and mortality when compared to amiodarone in atrial fibrillation patients with heart failure in contemporary real-world settings. Prospective studies are needed to determine whether propafenone should definitely be avoided in these patients.

SNAP25-dependent membrane trafficking of the Kv1.5 channel regulates the onset of atrial fibrillation

Synaptosomal-associated protein 25 kDa (SNAP25) is essential for vesicular trafficking and protein docking at presynaptic membranes in the nervous system, yet its role in the heart remains poorly understood. Here, we show an unrecognized function of SNAP25, which is selectively expressed in the atria, in regulating atrial electrical remodeling and the onset of atrial fibrillation (AF). SNAP25 protein is downregulated in the atria of AF patients. Cardiomyocyte-specific knockout of SNAP25 in male mice significantly shortens the atrial effective refractory period and action potential duration (APD), increasing susceptibility to AF, which is attributed to elevated Kv1.5 current and membrane expression. Blocking Kv1.5 channels effectively restores atrial APD and reduces AF incidence. Mechanistically, SNAP25 deficiency reduces the internalization of Kv1.5 from the cell surface membrane to early endosomes. In human iPSC-derived atrial cardiomyocytes, SNAP25 deficiency similarly elevates arrhythmic activity and accelerates repolarization. In conclusion, this study reveals that SNAP25 regulates AF susceptibility by controlling the trafficking of the atrial-specific Kv1.5 channel, highlighting SNAP25 as a promising therapeutic target for atrial arrhythmias.

Effectiveness and Safety of Edoxaban in the Routine Clinical Care of Atrial Fibrillation Patients in Brazil: Prospective 1-Year Follow-Up Study - EdoBRA

BACKGROUND

Edoxaban, an orally administered anticoagulant, has been shown to be safe and effective in preventing stroke in atrial fibrillation (AF) patients. Given its widespread use since approval, evaluating edoxaban's real-world performance in the Brazilian clinical context is crucial.

OBJECTIVE

The study aimed to report the one-year safety and effectiveness of edoxaban in AF patients in Brazil.

METHODS

EdoBRA is a multi-center, prospective, observational investigation conducted across 30 Brazilian research sites. Bleeding events were considered as safety measures and cardiovascular events were considered for effectiveness measures. Descriptive analyses were performed. Kaplan-Meier curves were generated for time-to-event analysis and a 95% confidence interval was used as appropriate.

RESULTS

Among the 705 enrolled participants, 590 were included in the analysis for having at least one follow-up or one reported event. Mean (±SD) CHA2DS2-VASc risk score was 3 (3.3 ± 1.6) and the mean HAS-BLED risk score was 2 (1.8 ± 1.2). During the one-year follow-up period, nine major bleedings events were reported, including five cases of gastrointestinal bleeding (IP 0.85 [95% CI =0.82; 0.88]). Among the cardiovascular events recorded (N = 68), there were four stroke events (IP 0.68 [CI 95% 0.65;0.71]), one transient ischemic attack (IP 0.17 [CI 95% (0.16;0.18]) and 1 event was Venous Thromboembolic Events (IP 0.17 [CI 95% (0.16;0.18]). No systemic embolic event was exhibited by any patient.

CONCLUSION

In an elderly population with several comorbidities routinely treated with edoxaban for AF, the rates of cardiovascular event and major bleeding were low.

Anticoagulation usage and thrombolytic therapy in subjects with atrial fibrillation-associated ischemic stroke

BACKGROUND

Atrial fibrillation (AF) causes up to 20% of ischemic strokes and 30% in some populations such as those more than 80 years. Previous research showed that widespread adoption of Direct Oral Anticoagulant (DOAC) prophylaxis had not been associated with a reduction in AF-associated stroke prevalence but there was a considerable rate of breakthrough stroke in patients receiving anticoagulation and anticoagulation rate may be affected by increasing use of DOACs.

AIMS

We undertook a more detailed study using the Irish National Audit of Stroke (INAS) to determine the characteristics of anticoagulation practice in AF-associated stroke, particularly breakthrough stroke, adherence to prescribing guidelines and effect on thrombolysis rate.

METHODS

Data from INAS were analyzed for the period 2017-2022 inclusive as part of a cross-sectional, cohort study. Data on pre-stroke and discharge disability (modified Rankin Score (mRS)) were collected in addition to age, sex, length of stay, and thrombolysis rate. An enhanced data set with additional questions about adherence with prescription, reasons for non-concordance, and International Normalized Ratio (INR) control for receiving warfarin was collected for 2022 and was also considered separately. Comparisons for continuous/quantitative data were made using Student's t-tests and for proportional data using Pearson's chi-square statistics and logistic regression analyses.

RESULTS

Complete AF data were available on 22,485 of 26,829 strokes admitted over this period. Of these strokes with AF data, 19,260 (85.6%) were ischemic, mean age was 71.8 years and 57.1% male. AF was found in 5321 of these ischemic strokes, and this AF was identified pre-stroke in 2835 (53.3%). In total, 80.4% of patients with known AF had been prescribed anticoagulation. The population with previously unknown AF was significantly younger on average than those on anticoagulation (76.8 years vs. 79.1 years (p < 0.0001, t-test)), or those with AF and not anticoagulated (78.8 years (p < 0.0001)); they were also much more likely to have received thrombolysis (17.3% vs. 4.0% (χ2, p < 0.0001)). Of 1794 patients receiving DOACs, only 52 received thrombolysis (2.9%) compared with 37 (8.5%) of the Vitamin K antagonist (VKA) group (χ2 = 29.0, p < 0.0001). On regression analysis, anticoagulation was not associated with differences in excellent outcome (modified Rankin Score (mRS) 0 or 1) achieved (odds ratio (OR) = 1.064, p = 0.41) or with mortality (OR = 1.014, p = 0.89). There were 4999 strokes in 2022, 4272 (85.4%) were ischemic, and 1270 (29.7%) of ischemic strokes were AF associated. Of the 557 AF-associated ischemic strokes anticoagulated at presentation, 84.6% were prescribed DOACs. Forty-eight (9.5%) had their anticoagulation paused, and 40 admitted to poor compliance (7.9%).

CONCLUSION

Nearly half of people with AF identified had not previously had the arrhythmia detected pre-stroke. Those admitted with known AF were mainly appropriately treated with DOACs and constitute breakthrough strokes. Subjects receiving DOACs were much less likely to receive thrombolytic therapy even than those taking warfarin.Data access:INAS data are publicly accessible. Data are available on application to National Office of Clinical Audit, Ireland.

Factor XI inhibitors for the prevention and treatment of venous and arterial thromboembolism

Therapeutic anticoagulation is essential to prevent and treat venous and arterial thromboembolism. The available agents target coagulation factors involved in thrombus formation but are associated with an increased risk of bleeding. Factor XI plays a minor role in haemostasis but contributes substantially to thrombus expansion, making it an attractive target to mitigate bleeding while maintaining antithrombotic efficacy. Various novel inhibitors, including antisense oligonucleotides, monoclonal antibodies and small molecules, have been developed. Phase II trials in orthopaedic surgery showed dose-dependent reductions in venous thromboembolism without significantly increasing bleeding compared with enoxaparin. In the first phase III trial of a small-molecule inhibitor of activated factor XI in patients with atrial fibrillation, asundexian was associated with a reduction in bleeding but also a higher risk of stroke, compared with apixaban. Factor XI inhibitors appear safe and hold promise for secondary prevention in myocardial infarction and ischaemic stroke, with ongoing phase III trials assessing their broader efficacy and safety. This Review discusses the rationale, pharmacology, evidence and future directions of factor XI inhibitors across various clinical settings.

The role of telemetry monitoring: From diagnosing arrhythmia to predictive models of patient instability

Over the past sixty years, telemetry monitoring has become integral to hospital care, offering critical insights into patient health by tracking key indicators like heart rate, respiratory rate, blood pressure, and oxygen saturation. Its primary application, continuous electrocardiographic (ECG) monitoring, is essential in diverse settings such as emergency departments, step-down units, general wards, and intensive care units for the early detection of cardiac rhythms signaling acute clinical deterioration. Recent advancements in data analytics and machine learning have expanded telemetry's role from observation to prognostication, enabling predictive models that forecast inhospital events indicative of patient instability. This short communication reviews the current applications and benefits of telemetry monitoring, including its vital role in identifying arrhythmias and predicting conditions like sepsis and cardiac arrest, while also addressing challenges such as alarm fatigue and the economic impact on health systems. It further explores opportunities for developing algorithms to enhance the practical use of telemetry data in clinical settings.

Left atrial appendage occlusion: behind the bleeding risk

Atrial fibrillation (AF) is the most common arrhythmia in adults and is associated with an increased risk of embolic stroke. The main prevention strategy for cerebral embolic events is based on the use of oral anticoagulant therapy (OAT). Left atrial appendage occlusion (LAAO) has demonstrated non-inferiority to OAT in clinical trials for prevention of stroke in non-valvular atrial fibrillation (NVAF). Patients with NVAF may still suffer ischemic strokes despite receiving adequate OAT.The physiopathological substrate remains unclear and only few theories can be proposed to explain the phenomenon and the approach to secondary prevention in these 'resistant strokes' remains largely empirical.Several therapeutic strategies have been proposed. Among these, LAAO should be taken into consideration. The procedure requires special planning in well selected patients, but can be performed successfully in most cases.

Caregiving for patients with atrial fibrillation: a systematic review of the scientific literature

AIMS

Caregiving processes and outcomes have been increasingly articulated in the cardiovascular literature, particularly in heart failure and coronary artery disease, but there has been no synthesis on caregiving for a patient with atrial fibrillation (AF). This review synthesizes scientific evidence that describes caregiving in the context of AF, with the aim of informing future research priorities for AF caregiving or clinical approaches that may support caregivers.

METHODS AND RESULTS

Informed by PRISMA guidelines, we conducted a mixed-methods systematic review with a data-based convergence design using a thematic synthesis approach. All studies that examined factors related to caregiving for patients with AF, as either a descriptive, predictor, or outcome variable, were included. After the search, data from 13 studies were abstracted; half of the studies (53%) were of low-to-moderate quality. Changes to the family unit and feelings of uncertainty are common post-AF; a subset of caregivers struggle with mental health challenges, particularly those who are unwell themselves or those who provide several hours of care to patients with more advanced symptoms or limitations. Informational support for caregivers appears to be lacking but is desired to better adapt to the changes or consequences incurred from AF.

CONCLUSION

This review complements findings from previous reviews conducted in other cardiovascular disease subgroups. As there is still limited high-quality research on caregiving in an AF context, additional research is required to adequately inform supportive programming for caregivers of patients with AF, if indicated.

REGISTRATION

PROSPERO: CRD4202339778.

Current Real-World Status of Oral Anticoagulant Management in Japanese Patients

Anticoagulant therapy is a drug therapy that inhibits the formation of blood clots. Although anticoagulants are effective in preventing thromboembolism, they also carry the risk of bleeding, so they must be managed carefully, taking both efficacy and safety into account. Evidence regarding the effectiveness and safety of each anticoagulant has already accumulated through many large clinical trials and post-marketing surveillance. However, when making decisions in clinical practice, it is necessary to always take into consideration differences in patient populations between clinical trials and actual clinical practice, as well as differences in historical background. (For example, there are differences in antiplatelet drugs and coronary artery interventions that were mainly used in each era.) In this review we discuss the effectiveness and safety of currently used anticoagulants, focusing on different patient backgrounds and points to keep in mind regarding their proper use, based on the latest reports in Asian populations, especially Japanese people, over the past 1-2 years.

Integrated Management of Persistent Atrial Fibrillation

The global incidence of atrial fibrillation is on the rise. Atrial fibrillation, a complex disease, heightens the likelihood of heart failure, stroke, and mortality, necessitating careful attention. Controlling heart rate and rhythm, addressing risk factors, and preventing strokes are fundamental in treating atrial fibrillation. Catheter ablation stands out as the primary approach for atrial fibrillation rhythm control. Nevertheless, the limited success rates pose a significant challenge to catheter ablation, particularly for persistent atrial fibrillation. Various adjunctive ablation techniques are currently under investigation to enhance the effectiveness of catheter ablation. This review provides an overview of the current state of the art and the latest optimized treatments for persistent atrial fibrillation in the areas of rhythm control, heart rate control, and risk factor management.

Atrial Fibrillation Surgery in the Era of Minimally Invasive Surgery: Biatrial Versus Left Atrial Maze

OBJECTIVE

Atrial fibrillation management is rapidly evolving, particularly for patients who are intolerant to medical therapy. Several catheter-based, surgical, and hybrid approaches currently exist, each with unique benefits that may be harnessed to provide optimal outcomes for these patients. This review focuses on the use of a biatrial lesion set versus an isolated left atrial lesion set for ablation.

METHODS

Major representative articles for each ablation strategy were identified and included. Terms searched on PubMed, Google Scholar, and Scopus included "atrial fibrillation ablation," "atrial fibrillation surgery," and "maze procedure," among others. Additional articles were included based on expert opinion.

RESULTS

The complete Cox maze biatrial lesion set has the highest efficacy but requires cardiopulmonary bypass. An isolated left atrial lesion set can also be performed, and these approaches are often less invasive but not as efficacious as the traditional complete maze operation.

CONCLUSIONS

Although biatrial ablation may carry a higher risk of conduction abnormalities than isolated left atrial ablation in the setting of atrial fibrillation, biatrial ablation is more efficacious in maintaining sinus rhythm.

Safety of catheter ablation for atrial fibrillation in patients with liver cirrhosis

BACKGROUND AND AIMS

Atrial fibrillation is the most prevalent cardiac arrhythmia, and catheter ablation (CA) has emerged as a viable treatment option for selected patients. However, its safety profile in liver cirrhosis (LC) populations remains underexplored.

METHODS

This was an observational analysis of the National Inpatient Sample Database 2016-2020; we analyzed adult encounters undergoing CA for atrial fibrillation who had a concomitant diagnosis of LC. Using propensity scores, encounters were divided into two cohorts based on the presence or absence of LC and matched in a 1:1 fashion using LC as the dependent variable. In-hospital mortality and postprocedure total complications were compared using regression models.

RESULTS

93 830 procedures were identified for non-LC patients and 960 involving LC patients; after propensity score matching, each cohort included 910 hospitalizations. The mean age in the LC-matched cohort was 66.5 ± 9.1 years. In-hospital mortality did not differ between the groups (aOR = 1.01; 95% CI [0.06-16.1]; p = .99). However, the LC cohort exhibited higher odds of total complications (aOR = 1.98; 95% CI [1.42-2.75]; p < .001). Length of stay (LOS) was comparable, but total costs were higher in the LC cohort: LOS was 2 days (95% CI [1-3]) in the LC group versus 3 days (95% CI [1-4]) (p < .11) and LC: $202,000 (95% CI [$142 000-$261 000]) versus non-LC: $189 000, (95% CI [$153 000-$222 000]) (p < .0001).

CONCLUSION

In this national analysis of patients undergoing CA for AF, those with LC had similar in-hospital mortality, postprocedure complications, and LOS compared to noncirrhotic patients. Furthermore, longitudinal studies are needed to assess the safety profile of CA in this subpopulation.

The Efficacy and Safety of Radio Electric Asymmetric Conveyer (REAC) External Radio Electric Reprogramming for Atrial Fibrillation (EX-RER AF) Treatment: Results From a Post-market Clinical Follow-Up

This post-market clinical follow-up (PMCF) study evaluates the clinical effectiveness and safety of the external radio electric reprogramming for atrial fibrillation (EX-RER AF) protocol, a non-invasive regenerative medicine approach utilizing radio electric asymmetric conveyer (REAC) technology for managing paroxysmal atrial fibrillation (PAF). Administered with the REAC BENE mod 110 device (ASMED, Scandicci, Italy), the treatment involves a standardized procedure, with the asymmetric conveyor probe (ACP) positioned in the precordial area and fixed, unmodifiable parameters ensuring consistency and reproducibility. During a 36-month post-market clinical follow-up (PMCF), 20 patients with prior diagnoses of PAF underwent the protocol. Significant reductions in symptom severity were observed, with the European Heart Rhythm Association (EHRA) score improving from 3.1 ± 0.4 to 1.8 ± 0.3 (p < 0.01). The quality of life (QoL), as assessed using the Short Form 36-item health survey (SF-36), demonstrated a mean score increase from 58 ± 7 to 78 ± 6 (p < 0.01) across all domains. The safety profile of the protocol was reinforced, with no adverse events reported during the follow-up period. The observed improvements align with the established mechanism of action of REAC technology, which optimizes endogenous bioelectrical activity and promotes the functional reorganization of cardiac conduction pathways. While these findings underscore the protocol's safety, effectiveness, and clinical utility as a non-invasive therapeutic option for PAF, further studies in larger, diverse populations and comparative trials with conventional treatments are warranted to validate long-term outcomes and broader applicability.

Rates of Visual Field Progression Before and After the Onset of Atrial Fibrillation

PRCIS

This case-control study investigated the effect of atrial fibrillation (AF) on the progression of glaucoma. The presence of AF and related microvascular damage was associated with a slightly faster visual field loss in glaucoma patients.

PURPOSE

To investigate the effect of atrial fibrillation (AF) on glaucoma progression.

METHODS

In this longitudinal case-control study, a total of 144 eyes from 105 patients with primary open angle glaucoma were included. Forty-eight eyes of case developed AF during the follow-up followed for 15.6 years. Ninety-six eyes of control that did not have AF at baseline or during follow-up matched for age, baseline glaucoma severity, and follow-up period were followed for an average of 14.7 years. Mixed-effects linear models were used to calculate the difference in the VF MD slopes before and after the AF. CHADS 2 and CHA 2 DS 2 -VASc scores were used to evaluate the risk of thrombosis event, and related microvascular damage was assessed based on these scores.

RESULTS

The rate of VF MD change was -0.20 (-0.42 to 0.02) dB/y before AF and -0.28 (-0.47 to -0.09) dB/y after AF for the patients with AF, and -0.21 (-0.25 to -0.17) dB/y for the control. In the multivariable models, the VF slope difference before and after the onset of AF [-0.10 (-0.14 to -0.05) dB/y, P <0.001], higher CHADS 2 score [-0.07 (-0.13 to 0.00) dB/y per 1 unit, P =0.040], and higher CHA 2 DS 2 -VASc score [-0.05 (-0.10 to 0.00) dB/y per 1 unit, P =0.039] were associated with faster VF MD loss.

CONCLUSIONS

The presence of atrial fibrillation and related microvascular damage might accelerate visual field loss. This underscores the need for a comprehensive medical history and management of cardiovascular risk factors to mitigate increased VF loss in glaucoma.

Trends over time in oral anticoagulation and stroke rates in atrial fibrillation: A community-based study

OBJECTIVES

Over the last decade, direct oral anticoagulants (DOAC) have become preferred over warfarin for stroke prevention in atrial fibrillation (AF). The objectives of this study were to quantify the shift over time from warfarin to DOACs and parallel changes in ischemic and hemorrhagic stroke rates in AF.

MATERIALS AND METHODS

This community-based retrospective study was undertaken within a single integrated health care network from 2011 to 2021. Changes over time in warfarin and DOAC use were quantified by year, both overall and stratified by CHA2DS2-VASc score. Ischemic and hemorrhagic stroke rate changes over time were evaluated by Poisson regression. Stroke rates were evaluated in different time eras: 2011-2015 and 2016-2021.

RESULTS

Among 31,978 AF patients followed an average of 5.5 years, any OAC use increased from 50.2 % (2011) to 59.4 % (2020) (p < 0.001). Warfarin use decreased from 49.3 % to 30.8 %, while DOAC use increased from 2.0 % to 30.8 % (both p < 0.001). In 2020, patients with CHA2DS2-VASc 0-1 and 2-5 were more likely to use DOACs than warfarin (18.6 % vs. 6.7 %; 33.0 % vs. 28.2 %), whereas in CHA2DS2-VASc 6-9 DOACs were used less frequently (30.0 % vs. 40.8 %). Ischemic stroke rates significantly increased by 19 % (95 % CI: 7 %, 32 %) from 2011 to 2015, but significantly decreased by 18 % (10 %, 26 %) from 2016 to 2021. Hemorrhagic stroke rates stabilized in 2016-2021 (+3 %; -18 %, 30 %) after increasing in 2011-2015 (+36 %; 4 %, 78 %).

CONCLUSION

Improvements in ischemic and hemorrhagic stroke rates coincided temporally with increased uptake of OACs and a shift toward increased uptake of DOACs relative to warfarin.

Atrial tachyarrhythmia prevention by Shensong Yangxin after catheter ablation for persistent atrial fibrillation: the SS-AFRF trial

BACKGROUND AND AIMS

Despite advances in technology and techniques, the recurrence rate of persistent atrial fibrillation (AF) following catheter ablation remains high. The Shensong Yangxin (SSYX) capsule, a renowned traditional Chinese medicine formula, is used in the treatment of cardiac arrhythmias. This trial aimed to investigate whether the SSYX can improve clinical outcomes in patients who have undergone catheter ablation for persistent AF.

METHODS

A multi-centre, randomized, double-blind, placebo-controlled clinical trial was conducted at 66 centres in China among 920 patients with persistent AF undergoing first ablation. Participants were randomized to oral SSYX, 1.6 g (.4 g/granule) thrice daily (n = 460), or matched placebo (n = 460) for 12 months. The primary endpoint was recurrent atrial tachyarrhythmias lasting for ≥30 s following a blanking period of 3 months. Secondary endpoints included time to first documented atrial tachyarrhythmias, AF burden, cardioversion, stroke/systemic embolism, changes in echocardiographic parameters, and quality-of-life (QoL) score. Analyses were performed according to the intention-to-treat principle.

RESULTS

A total of 920 patients underwent randomization (460 assigned to SSYX group and 460 assigned to placebo group). During the follow-up of 12 months, patients assigned to SSYX had a higher event-free rate from recurrent atrial tachyarrhythmias when compared with the placebo group (12-month Kaplan-Meier event-free rate estimates, 85.5% and 77.7%, respectively; hazard ratio, .6; 95% confidence interval .4-.8; P = .001). Patients assigned to receive SSYX had a better QoL score at 12 months compared to those randomized to placebo. There was no significant difference in the incidence of serious adverse events between the two groups.

CONCLUSIONS

Treatment with SSYX following radiofrequency catheter ablation for persistent AF reduced the incidence of recurrent atrial tachyarrhythmias and led to clinically significant improvements in QoL during a 12-month follow-up in a Chinese population.

Predictive value of the left atrioventricular coupling index for recurrence after radiofrequency ablation of paroxysmal atrial fibrillation

BACKGROUND

Although patients with paroxysmal atrial fibrillation (PAF) are preferred to undergo catheter ablation (CA), the high possibility of recurrence following surgery is still concerning. We aimed to evaluate the ability of the left atrioventricular coupling index (LACI), which is the ratio of the left atrium end-diastolic volume to the left ventricle end-diastolic volume, to predict PAF recurrence after CA.

METHODS

Patients with PAF undergoing CA for the first time between January 2018 and June 2021 were admitted and grouped by recurrence within a year. LACI was measured before CA using ultrasonography. Risk factors identified by multivariable logistic regression analysis, and the area under the receiver operating characteristic (ROC) curve was used to assess the ability of LACI to predict PAF recurrence after CAP.

RESULTS

Among the 204 patients treated at our hospital, 164 patients were included in the research after eliminating those who were lost to follow-up. Among them, 56 individuals had recurrence following a 90-day blanking period. Recurrence is more likely in elderly patients with high blood pressure. Patients who suffered recurrence exhibited lower left atrial ejection fraction and increased LACI, left atrial volume minimum, and left atrium volume index maximum. LACI was an independent risk factor for postoperative recurrence (OR: 1.526, 95% CI: 1.325-1.757, P < 0.001), and ROC displayed remarkable predictive value [area under the curve (AUC) = 0.868].

CONCLUSIONS

High LACI is significantly associated with postoperative recurrence in PAF patients, and LACI has incremental prognostic value to predict recurrence.

Therapeutic Spp1 silencing in TREM2+ cardiac macrophages suppresses atrial fibrillation

Atrial fibrillation (AFib) and the risk of its lethal complications are propelled by fibrosis, which induces electrical heterogeneity and gives rise to reentry circuits. Atrial TREM2+ macrophages secrete osteopontin (encoded by Spp1), a matricellular signaling protein that engenders fibrosis and AFib. Here we show that silencing Spp1 in TREM2+ cardiac macrophages with an antibody-siRNA conjugate reduces atrial fibrosis and suppresses AFib in mice, thus offering a new immunotherapy for the most common arrhythmia.

Repurposing Metformin for the Treatment of Atrial Fibrillation: Current Insights

Metformin is an orally effective anti-hyperglycemic drug that despite being introduced over 60 years ago is still utilized by an estimated 120 to 150 million people worldwide for the treatment of type 2 diabetes (T2D). Metformin is used off-label for the treatment of polycystic ovary syndrome (PCOS) and for pre-diabetes and weight loss. Metformin is a safe, inexpensive drug with side effects mostly limited to gastrointestinal issues. Prospective clinical data from the United Kingdom Prospective Diabetes Study (UKPDS), completed in 1998, demonstrated that metformin not only has excellent therapeutic efficacy as an anti-diabetes drug but also that good glycemic control reduced the risk of micro- and macro-vascular complications, especially in obese patients and thereby reduced the risk of diabetes-associated cardiovascular disease (CVD). Based on a long history of clinical use and an excellent safety record metformin has been investigated to be repurposed for numerous other diseases including as an anti-aging agent, Alzheimer's disease and other dementias, cancer, COVID-19 and also atrial fibrillation (AF). AF is the most frequently diagnosed cardiac arrythmia and its prevalence is increasing globally as the population ages. The argument for repurposing metformin for AF is based on a combination of retrospective clinical data and in vivo and in vitro pre-clinical laboratory studies. In this review, we critically evaluate the evidence that metformin has cardioprotective actions and assess whether the clinical and pre-clinical evidence support the use of metformin to reduce the risk and treat AF.

Atrial fibrillation type and long-term clinical outcomes in hospitalized patients with heart failure: insight from JROADHF

AIMS

Atrial fibrillation (AF) type (paroxysmal, persistent, or permanent) is important in determining therapeutic management; however, clinical outcomes by AF type are largely unknown for hospitalized patients with heart failure (HF).

METHODS AND RESULTS

The Japanese Registry Of Acute Decompensated Heart Failure is a retrospective, multicenter, and nationwide registry of patients hospitalized for acute HF in Japan. Follow-up data were collected up to 5 years after hospitalization. Patients were divided based on diagnosis and AF type into 3 groups [without AF, paroxysmal AF, and sustained AF (defined as a composite of persistent and permanent AF)], and compared the backgrounds and outcomes between the groups. Of 12 895 hospitalized HF patients [mean age: 78 ± 13 years, female: 6077 (47%), and mean left ventricular ejection fraction: 47 ± 17%], 1725 had paroxysmal AF, and 3672 had sustained AF. Compared with patients without AF, sustained AF had a higher risk of the primary composite endpoint of cardiovascular (CV) death or HF hospitalization [hazard ratio (HR): 1.09, 95% confidence interval (CI): 1.01-1.17; P = 0.03], mainly driven by HF hospitalization [HR: 1.16, 95% CI: 1.06-1.26; P < 0.001], whereas the corresponding risk for the primary endpoint in patients with paroxysmal AF was not elevated (HR: 1.03, 95% CI: 0.94-1.13; P = 0.53) after adjustment by multivariable Cox regression analysis. These results were consistent among the subgroups of patients with reduced or preserved ejection fraction (interaction P = 0.74).

CONCLUSION

Among hospitalized patients with HF, sustained AF, but not paroxysmal AF, was significantly associated with a higher risk for CV death or HF hospitalization, indicating the importance of accounting for AF type in HF patients.

Serious Bleeding in Patients With Atrial Fibrillation Using Diltiazem With Apixaban or Rivaroxaban

Importance

Diltiazem, a commonly prescribed ventricular rate-control medication for patients with atrial fibrillation, inhibits apixaban and rivaroxaban elimination, possibly causing overanticoagulation.

Objective

To compare serious bleeding risk for new users of apixaban or rivaroxaban with atrial fibrillation treated with diltiazem or metoprolol.

Design, Setting, and Participants

This retrospective cohort study included Medicare beneficiaries aged 65 years or older with atrial fibrillation who initiated apixaban or rivaroxaban use and also began treatment with diltiazem or metoprolol between January 1, 2012, and November 29, 2020. Patients were followed up to 365 days through November 30, 2020. Data were analyzed from August 2023 to February 2024.

Exposures

Diltiazem and metoprolol.

Main Outcomes and Measures

The primary outcome was a composite of bleeding-related hospitalization and death with recent evidence of bleeding. Secondary outcomes were ischemic stroke or systemic embolism, major ischemic or hemorrhagic events (ischemic stroke, systemic embolism, intracranial or fatal extracranial bleeding, or death with recent evidence of bleeding), and death without recent evidence of bleeding. Hazard ratios (HRs) and rate differences (RDs) were adjusted for covariate differences with overlap weighting.

Results

The study included 204 155 US Medicare beneficiaries, of whom 53 275 received diltiazem and 150 880 received metoprolol. Study patients (mean [SD] age, 76.9 [7.0] years; 52.7% female) had 90 927 person-years (PY) of follow-up (median, 120 [IQR, 59-281] days). Patients receiving diltiazem treatment had increased risk for the primary outcome (RD, 10.6 [95% CI, 7.0-14.2] per 1000 PY; HR, 1.21 [95% CI, 1.13-1.29]) and its components of bleeding-related hospitalization (RD, 8.2 [95% CI, 5.1-11.4] per 1000 PY; HR, 1.22 [95% CI, 1.13-1.31]) and death with recent evidence of bleeding (RD, 2.4 [95% CI, 0.6-4.2] per 1000 PY; HR, 1.19 [95% CI, 1.05-1.34]) compared with patients receiving metoprolol. Risk for the primary outcome with initial diltiazem doses exceeding 120 mg/d (RD, 15.1 [95% CI, 10.2-20.1] per 1000 PY; HR, 1.29 [95% CI, 1.19-1.39]) was greater than that for lower doses (RD, 6.7 [95% CI, 2.0-11.4] per 1000 PY; HR, 1.13 [95% CI, 1.04-1.24]). For doses exceeding 120 mg/d, the risk of major ischemic or hemorrhagic events was increased (HR, 1.14 [95% CI, 1.02-1.27]). Neither dose group had significant changes in the risk for ischemic stroke or systemic embolism or death without recent evidence of bleeding. When patients receiving high- and low-dose diltiazem treatment were directly compared, the HR for the primary outcome was 1.14 (95% CI, 1.02-1.26).

Conclusions and Relevance

In Medicare patients with atrial fibrillation receiving apixaban or rivaroxaban, diltiazem was associated with greater risk of serious bleeding than metoprolol, particularly for diltiazem doses exceeding 120 mg/d.

Atrial Fibrillation Burden: Impact on Stroke Risk and Beyond

Atrial fibrillation (AF) is an important independent risk factor for stroke. Current guidelines handle AF as a binary entity with risk driven by the presence of clinical risk factors, which guides the decision to treat with an oral anticoagulant. Recent studies in the literature suggest a dose-response relationship between AF burden and stroke risk, in both clinical AF and subclinical atrial fibrillation (SCAF), which differs from current guidance to disregard burden and utilize clinical risk scores alone. Within clinical classification and at the same risk levels in various scores, the risk of stroke increases with AF burden. This opens the possibility of incorporating burden into risk profiles, which has already shown promise. Long-term rhythm monitoring is needed to elucidate SCAF in patients with stroke. Recent data from randomized trials are controversial regarding whether there is an independent risk from AF episodes with a duration of less than 24 h, including the duration of SCAF greater than six minutes but less than 24 h.

Implications of Atrial Fibrillation for Guideline-Directed Therapy in Patients With Heart Failure: JACC State-of-the-Art Review

Atrial fibrillation (AF) and heart failure (HF) are common cardiovascular conditions that frequently coexist. Among patients with HF, more than one-half also have AF. Both are associated with significant morbidity and mortality. Moreover, the prevalence of each is increasing globally, and this trend is expected to continue owing to an aging population and increased life expectancy. Diagnosis of AF in a patient with HF is associated with greater symptom burden, more frequent hospitalizations, and a worse prognosis. Guideline-directed medical therapy (GDMT) for HF can affect the incidence of AF. Once present, AF can influence the efficacy of some components of GDMT for HF. In this review, we discuss the effect of GDMT for HF across the spectrum of ejection fraction on prevention of AF as well as the benefit of GDMT in patients with vs without AF.

Novel scoring system derived from meta-analysis and validated in cohort population for predicting 1-year atrial fibrillation recurrence after cryoballoon catheter ablation: The HeLPS-Cryo score

BACKGROUND

Atrial fibrillation (AF) recurrence rates in 1 year after cryoballoon ablation catheter (CBCA) are still high. We purposed to identify strong predictors for AF recurrence after the successful CBCA procedure and develop a new scoring system based only on pre-procedural parameters.

METHODS

In the derivation phase, a systematic review and meta-analysis identified the strong predictors of AF recurrence after the CBCA. The pooled hazard ratio (HR) was used to create the new scoring system. The second phase validated the new scoring system in the cohort population.

RESULTS

A meta-analysis including 29 cohort studies with 16196 participants confirmed that persistent AF, stroke, heart failure, and left atrial diameter (LAD) >40 mm were powerful predictors for AF recurrence after the CBCA procedure. The HeLPS-Cryo (heart failure [1], left atrial dilatation [1], persistent AF [2], and stroke [2]) was developed based on those pre-procedural predictors. It was validated in 140 patients receiving CBCA procedures and revealed excellent predictive performance for 1-year AF recurrence (AUC = 0.8877; 95% CI = 0.8208 to 0.9546). The HeLPS-Cryo score of ≥3 could predict 1-year AF recurrence with sensitivity and specificity of 78.9% and 87.9%, respectively. The positive predictive value was 66.7%, and the negative predictive value was 93.1%.

CONCLUSION

The HeLPS-Cryo score can help the physician estimate the probability of 1-year AF recurrence after the successful CBCA procedure. Patients with HeLPS-Cryo score <3 are good candidates for the CBCA procedure.

Changes in anticoagulation practice in subjects admitted with stroke associated with atrial fibrillation, following introduction of direct oral anticoagulants over 2013-2021

BACKGROUND

The adoption of direct oral anticoagulants (DOACs) has changed practice in prevention of stroke in atrial fibrillation (AF). We used Irish data national data on stroke and anticoagulation therapy over 9 years to investigate changes in anticoagulation practice and potential consequences on stroke prevalence and thrombolysis.

METHODS

AF, anticoagulation, thrombolysis, and stroke data from the Irish National Audit of Stroke (INAS) 2013-2021 were reviewed. The proportion of patients with ischemic stroke (IS) and intracerebral hemorrhage (IH) with known AF admitted on anticoagulation was determined. Effects on age distribution in the population and thrombolysis practice were assessed.

RESULTS

AF data were available on 34,630 of 35,241 individuals (98.3%) included in INAS; median age was 74 years and 56% were male. AF was found in 10,016 (28.9%, 9059 IS, 957 IH). 6313 had known AF prior to stroke (63.1%). The proportion all total IS due to AF decreased by 15.3% (31.3%-26.5%, chi-square = 24.6, p < 0.0001). The proportion of IH did not change significantly (21.6%-20.2%, chi-square = 1.8, p = 0.18). Over the 9 years, 3875 (38.6%) of the subjects with AF were recorded as receiving anticoagulants at admission. In 2013, 4.4% of AF-associated strokes were admitted on a DOAC and 21.4% on warfarin; by 2021, 44.1% were receiving a DOAC and 6.2% warfarin. There was a strong inverse correlation between the proportion of anticoagulated stroke patients and the total proportion of AF-associated strokes over time (r = -0.82, p = 0.006). In contrast, no correlation was found between increasing DOAC usage and IH (r = 0.14, p = 0.71). Increased anticoagulation usage correlated with a reduction in patients ⩾ 80 years (r = -0.83, p = 0.006) and also correlated with a relative reduction of 30.1% in subjects thrombolysed <4 h from onset (r = -0.89, p = 0.001).

CONCLUSION

DOACs have led to increased use of anticoagulation, but warfarin use fell by two-thirds. There has been a reduction in the proportion of AF-associated IS without a noticeable increase in IH. Increased anticoagulation correlated with reduced numbers of strokes in those >80 years and in the proportion of patients thrombolysed.

Kidney Function, Albuminuria, and Risk of Incident Atrial Fibrillation: A Systematic Review and Meta-Analysis

RATIONALE & OBJECTIVE

Atrial fibrillation (AF) and chronic kidney disease (CKD) often coexist. However, it is not known whether CKD is an independent risk factor for incident AF. Therefore, we evaluated the association between markers of CKD-estimated glomerular filtration rate (eGFR) and albuminuria-and incident AF.

STUDY DESIGN

Systematic review and meta-analysis of cohort studies and randomized controlled trials.

SETTING & STUDY POPULATIONS

Participants with measurement of eGFR and/or albuminuria who were not receiving dialysis.

SELECTION CRITERIA FOR STUDIES

Cohort studies and randomized controlled trials were included that reported incident AF risk in adults according to eGFR and/or albuminuria.

ANALYTICAL APPROACH

Age- or multivariate-adjusted risk ratios (RRs) for incident AF were extracted from cohort studies, and RRs for each trial were derived from event data. RRs for incident AF were pooled using random-effects models.

RESULTS

38 studies involving 28,470,249 participants with 530,041 incident AF cases were included. Adjusted risk of incident AF was greater among participants with lower eGFR than those with higher eGFR (eGFR<60 vs≥60mL/min/1.73m2: RR, 1.43; 95% CI, 1.30-1.57; and eGFR<90 vs≥90mL/min/1.73m2: RR, 1.42; 95% CI, 1.26-1.60). Adjusted incident AF risk was greater among participants with albuminuria (any albuminuria vs no albuminuria: RR, 1.43; 95% CI, 1.25-1.63; and moderately to severely increased albuminuria vs normal to mildly increased albuminuria: RR, 1.64; 95% CI, 1.31-2.06). Subgroup analyses showed an exposure-dependent association between CKD and incident AF, with the risk increasing progressively at lower eGFR and higher albuminuria categories.

LIMITATIONS

Lack of patient-level data, interaction between eGFR and albuminuria could not be evaluated, possible ascertainment bias due to variation in the methods of AF detection.

CONCLUSIONS

Lower eGFR and greater albuminuria were independently associated with increased risk of incident AF. CKD should be regarded as an independent risk factor for incident AF.

PLAIN-LANGUAGE SUMMARY

Irregular heartbeat, or atrial fibrillation (AF), is the commonest abnormal heart rhythm. AF occurs commonly in people with chronic kidney disease (CKD), and CKD is also common in people with AF. However, CKD in not widely recognized as a risk factor for new-onset or incident AF. In this research, we combined data on more than 28 million participants in 38 studies to determine whether CKD itself increases the chances of incident AF. We found that both commonly used markers of kidney disease (estimated glomerular filtration rate and albuminuria, ie, protein in the urine) were independently associated with a greater risk of incident AF. This finding suggests that CKD should be recognized as an independent risk factor for incident AF.

Frequent Premature Atrial Contractions Lead to Adverse Atrial Remodeling and Atrial Fibrillation in a Swine Model

BACKGROUND

Frequent premature atrial complexes (PACs) are associated with future incident atrial fibrillation (AF), but whether PACs contribute to development of AF through adverse atrial remodeling has not been studied. This study aimed to explore the effect of frequent PACs from different sites on atrial remodeling in a swine model.

METHODS

Forty swine underwent baseline electrophysiologic studies and echocardiography followed by pacemaker implantations and paced PACs (50% burden) at 250-ms coupling intervals for 16 weeks in 4 groups: (1) lateral left atrium (LA) PACs by the coronary sinus (Lat-PAC; n=10), (2) interatrial septal PACs (Sep-PAC; n=10), (3) regular LA pacing at 130 beats/min (Reg-130; n=10), and (4) controls without PACs (n=10). At the final study, repeat studies were performed, followed by tissue histology and molecular analyses focusing on fibrotic pathways.

RESULTS

Lat-PACs were associated with a longer P-wave duration (93.0±9.0 versus 74.2±8.2 and 58.8±7.6 ms; P<0.001) and greater echocardiographic mechanical dyssynchrony (57.5±11.6 versus 35.7±13.0 and 24.4±11.1 ms; P<0.001) compared with Sep-PACs and controls, respectively. After 16 weeks, Lat-PACs led to slower LA conduction velocity (1.1±0.2 versus 1.3±0.2 [Sep-PAC] versus 1.3±0.1 [Reg-130] versus 1.5±0.2 [controls] m/s; P<0.001) without significant change in atrial ERP. The Lat-PAC group had a significantly increased percentage of LA fibrosis and upregulated levels of extracellular matrix proteins (lysyl oxidase and collagen 1 and 8), as well as TGF-β1 (transforming growth factor-β1) signaling proteins (latent and monomer TGF-β1 and phosphorylation/total ratio of SMAD2/3; P<0.05). The Lat-PAC group had the longest inducible AF duration (terminal to baseline: 131 [interquartile range 30, 192] seconds versus 16 [6, 26] seconds [Sep-PAC] versus 22 [11, 64] seconds [Reg-130] versus -1 [-16, 7] seconds [controls]; P<0.001).

CONCLUSIONS

In this swine model, frequent PACs resulted in adverse atrial structural remodeling with a heightened propensity to AF. PACs originating from the lateral LA produced greater atrial remodeling and longer induced AF duration than the septal-origin PACs. These data provide evidence that frequent PACs can cause adverse atrial remodeling as well as AF, and that the location of ectopic PACs may be clinically meaningful.

Influence of thrombocytopenia on bleeding and vascular events in atrial fibrillation

Whether thrombocytopenia substantively increases the risk of hemorrhage associated with anticoagulation in patients with atrial fibrillation (AF) is not established. The purpose of this study was to compare rates of bleeding in patients with AF and thrombocytopenia (platelet count < 100 000/μL) to patients with AF and normal platelet counts (>150 000/μL). We performed a propensity score-matched, retrospective cohort study of adults (n = 1070) with a new diagnosis of AF who received a prescription for an oral anticoagulant between 2015 and 2020. The thrombocytopenia cohort was defined as having at least 2 platelet counts <100 000/μL on separate days in the period spanning the 12 weeks preceding the initiation of anticoagulation to 6 weeks after the initiation of anticoagulation. The primary end point was the 1-year cumulative incidence of major bleeding; secondary end points included clinically relevant bleeding, arterial and venous thrombotic events, and all-cause mortality. Patients with AF and thrombocytopenia experienced a higher 1-year cumulative incidence of major bleeding (13.3% vs 5.7%; P < .0001) and clinically relevant bleeding (24.5% vs 16.7%; P = .005) than the controls. Thrombocytopenia was identified as an independent risk factor for major bleeding (hazard ratio, 2.20; confidence interval, 1.36-3.58; P = .001), with increasing risk based on the severity of thrombocytopenia. The cumulative incidence of arterial thrombosis at 1 year was 3.6% in the group with thrombocytopenia and 1.5% in controls (Gray test, P = .08). These findings suggest that baseline platelet counts are an important biomarker for hemorrhagic outcomes in AF and that the degree of thrombocytopenia is an important factor in determining the level of risk.

Selection of Non-vitamin K Antagonist Oral Anticoagulant for Stroke Prevention in Atrial Fibrillation Based on Patient Profile: Perspectives from Vietnamese Experts. Part 1

In Asia, especially Vietnam, AF is a common arrhythmia and is linked to a higher risk of stroke and systemic embolism. Anticoagulation therapy for stroke prevention in AF patients can result in bleeding complications. To effectively manage AF, adopting appropriate anticoagulation and addressing modifiable risk factors are crucial. Vietnamese clinicians are particularly interested in non-vitamin K antagonist oral anticoagulants (NOACs), a recent development in AF treatment. However, the lack of head-to-head trials comparing NOACs makes selecting a specific NOAC challenging. This review aims to provide a comprehensive overview of the available clinical evidence on NOACs for stroke prevention in AF to assist clinicians in making informed decisions and improving treatment outcomes in patients with AF. The first part of this review will present the current landscape of AF in Vietnam, focusing on AF prevalence and highlighting gaps in clinical practice. Furthermore, this part extensively discusses the anticoagulation strategy for both primary and secondary stroke prevention in AF.

Robotic magnetic navigation-guided catheter ablation establishes highly effective pulmonary vein isolation in patients with paroxysmal atrial fibrillation when compared to conventional ablation techniques

INTRODUCTION

Pulmonary vein isolation (PVI) is a pivotal part of ablative therapy for atrial fibrillation (AF). Currently, there are multiple techniques available to realize PVI, including: manual-guided cryoballoon (MAN-CB), manual-guided radiofrequency (MAN-RF), and robotic magnetic navigation-guided radiofrequency ablation (RMN-RF). There is a lack of large prospective trials comparing contemporary RMN-RF with the more conventional ablation techniques. This study prospectively compared three catheter ablation techniques as treatment of paroxysmal AF.

METHODS

This multicenter, prospective study included patients with paroxysmal AF who underwent their first ablation procedure. Procedural parameters (including procedural efficiency), complication rates, and freedom of AF during 12-month follow-up, were compared between three study groups which were defined by the utilized ablation technique.

RESULTS

A total of 221 patients were included in this study. Total procedure time was significantly shorter in MAN-CB (78 ± 21 min) compared to MAN-RF (115 ± 41 min; p < .001) and compared to RMN-RF (129 ± 32 min; p < .001), whereas it was comparable between the two radiofrequency (RF) groups (p = .062). A 3% complication rate was observed, which was comparable between all groups. At 12-month follow-up, AF recurrence was observed in 40 patients (19%) and was significantly lower in the robotic group (MAN-CB 19 [24%], MAN-RF 16 [23%], RMN-RF 5 [8%] AF recurrences, p = .045) (multivariate hazard ratio of RMN-RF on AF recurrence 0.32, 95% confidence interval: 0.12-0.87, p = .026).

CONCLUSION

RMN-guided PVI results in high freedom of AF in patients with paroxysmal AF, when compared to cryoablation and manual RF ablation. Cryoablation remains the most time-efficient ablation technique, whereas RMN nowadays has comparable efficiency with manual RF ablation.

Identification of a Novel Target Implicated in Chronic Obstructive Sleep Apnea-Related Atrial Fibrillation by Integrative Analysis of Transcriptome and Proteome

Objective

This study aimed to identify a newly identified target involved in atrial fibrillation (AF) linked to chronic obstructive sleep apnea (COSA) through an integrative analysis of transcriptome and proteome.

Methods

Fifteen beagle canines were randomly assigned to three groups: control (CON), obstructive sleep apnea (OSA), and OSA with superior left ganglionated plexi ablation (OSA+GP). A COSA model was established by intermittently obstructing the endotracheal cannula during exhalation for 12 weeks. Left parasternal thoracotomy through the fourth intercostal space allowed for superior left ganglionated plexi (SLGP) ablation. In vivo open-chest electrophysiological programmed stimulation was performed to assess AF inducibility. Histological, transcriptomic, and proteomic analyses were conducted on atrial samples.

Results

After 12 weeks, the OSA group exhibited increased AF inducibility and longer AF durations compared to the CON group. Integrated transcriptomic and proteomic analyses identified 2422 differentially expressed genes (DEGs) and 1194 differentially expressed proteins (DEPs) between OSA and CON groups, as well as between OSA+GP and OSA groups (1850 DEGs and 1418 DEPs). The analysis revealed that differentially regulated DEGs were primarily enriched in mitochondrial biological processes in the CON-vs.-OSA and OSA-vs.-GP comparisons. Notably, the key regulatory molecule GSTZ1 was activated in OSA and inhibited by GP ablation.

Conclusion

These findings suggest that GSTZ1 may play a pivotal role in mitochondrial damage, triggering AF substrate formation, and increasing susceptibility to AF in the context of COSA.

Network Meta-Analysis of Initial Antithrombotic Regimens After Left Atrial Appendage Occlusion

BACKGROUND

The optimal antithrombotic therapy following left atrial appendage occlusion (LAAO) in patients with nonvalvular atrial fibrillation (AF) remains uncertain.

OBJECTIVES

In this study, the authors sought to compare the efficacy and safety of various antithrombotic strategies after LAAO.

METHODS

We searched the Medline, Cochrane, EMBASE, LILACS, and ClinicalTrials.gov databases for studies reporting outcomes after LAAO, stratified by antithrombotic therapy prescribed at postprocedural discharge. Direct oral anticoagulants (DOACs), vitamin K antagonists (VKAs), single antiplatelet therapy (SAPT), dual antiplatelet therapy (DAPT), DOAC plus SAPT, VKA plus SAPT, and no antithrombotic therapy were analyzed. We performed a frequentist random effects model network meta-analysis to estimate the OR and 95% CI for each comparison. P-scores provided a ranking of treatments.

RESULTS

Forty-one studies comprising 12,451 patients with nonvalvular AF were included. DAPT, DOAC, DOAC plus SAPT, and VKA were significantly superior to no therapy to prevent device-related thrombosis. DOAC was associated with lower all-cause mortality than VKA (OR: 0.39; 95% CI: 0.17-0.89; P = 0.03). Compared with SAPT, DAPT was associated with fewer thromboembolic events (OR: 0.50; 95% CI: 0.29-0.88; P = 0.02), without a difference in major bleeding. In the analysis of P-scores, DOAC monotherapy was the strategy most likely to have lower thromboembolic events and major bleeding.

CONCLUSIONS

In this network meta-analysis comparing initial antithrombotic therapies after LAAO, monotherapy with DOAC had the highest likelihood of lower thromboembolic events and major bleeding. DAPT was associated with a lower incidence of thromboembolic events compared with SAPT and may be a preferred option in patients unable to tolerate anticoagulation.

Integrative human atrial modelling unravels interactive protein kinase A and Ca2+/calmodulin-dependent protein kinase II signalling as key determinants of atrial arrhythmogenesis

AIMS

Atrial fibrillation (AF), the most prevalent clinical arrhythmia, is associated with atrial remodelling manifesting as acute and chronic alterations in expression, function, and regulation of atrial electrophysiological and Ca2+-handling processes. These AF-induced modifications crosstalk and propagate across spatial scales creating a complex pathophysiological network, which renders AF resistant to existing pharmacotherapies that predominantly target transmembrane ion channels. Developing innovative therapeutic strategies requires a systems approach to disentangle quantitatively the pro-arrhythmic contributions of individual AF-induced alterations.

METHODS AND RESULTS

Here, we built a novel computational framework for simulating electrophysiology and Ca2+-handling in human atrial cardiomyocytes and tissues, and their regulation by key upstream signalling pathways [i.e. protein kinase A (PKA), and Ca2+/calmodulin-dependent protein kinase II (CaMKII)] involved in AF-pathogenesis. Populations of atrial cardiomyocyte models were constructed to determine the influence of subcellular ionic processes, signalling components, and regulatory networks on atrial arrhythmogenesis. Our results reveal a novel synergistic crosstalk between PKA and CaMKII that promotes atrial cardiomyocyte electrical instability and arrhythmogenic triggered activity. Simulations of heterogeneous tissue demonstrate that this cellular triggered activity is further amplified by CaMKII- and PKA-dependent alterations of tissue properties, further exacerbating atrial arrhythmogenesis.

CONCLUSIONS

Our analysis reveals potential mechanisms by which the stress-associated adaptive changes turn into maladaptive pro-arrhythmic triggers at the cellular and tissue levels and identifies potential anti-AF targets. Collectively, our integrative approach is powerful and instrumental to assemble and reconcile existing knowledge into a systems network for identifying novel anti-AF targets and innovative approaches moving beyond the traditional ion channel-based strategy.

Association between elevated CHA2DS2-VASC score and contrast-induced nephropathy among patients undergoing percutaneous coronary intervention: a systematic review and meta-analysis

BACKGROUND

Promising results with the CHA2DS2-VASc risk score (CVRS) have been reported for the prediction of contrast-induced nephropathy (CIN). The aim of this study is to consolidate all the data available and examine the association between elevated CVRS and the incidence of CIN in patients undergoing percutaneous coronary intervention (PCI).

METHODS

We systematically searched PubMed, Embase, and Scopus for abstracts and full-text articles from inception to May 2022. Studies were included if they evaluated the association between a high CVRS and the incidence of CIN in patients undergoing PCI. Data were integrated using the random-effects, generic inverse variance method of DerSimonian and Laird. Prospero registration: CRD42022334065.

RESULTS

Seven studies from 2016 to 2021 with a total of 7,401 patients were included. In patients undergoing PCI, a high CVRS (≥2: Odds ratio [OR]:2.98, 95% confidence interval [95% CI] 2.25-3.94, p < .01, I2 = 1%, ≥3: OR 4.46, 95% CI 2.27-8.78, p < .01, I2=56% and ≥4: OR:2.75, 95% CI 1.76-4.30, p < .01, I2 = 11%) was significantly associated with an increase incidence for CIN. Subgroup analyses were done in patients with acute coronary syndrome, and association with CIN remained statistically significant (≥2: OR 2.93, 95% CI 2.11-4.07, p < .01, I2=22%and ≥4: OR:2.24, 95% CI 1.36-3.69, p < .01, I2 = 0%,).

CONCLUSION

In patients undergoing PCI, an elevated CVRS is associated with an increased risk for CIN. More rigorous studies are needed to clarify this association and to identify strategies to reduce CIN.

Percutaneous Left Atrial Appendage Occlusion: What the Practising Physician Should Know

Non-valvular AF is a common clinical condition associated with an increased risk of thromboembolic complications. As a consequence, oral anticoagulant therapy (OAT) is the cornerstone of non-valvular AF management. Despite the well-established efficacy of OAT, many patients cannot receive this preventive therapy due to bleeding or a high risk of bleeding. The fact that more than 90% of thrombi are formed in the left atrial appendage has led to the development of alternative methods to reduce the embolic risk. Left atrial appendage occlusion (LAAO) is a non-pharmacological option for preventing cardioembolic events in patients with non-valvular AF with a contraindication to OAT. The demand for LAAO procedures is growing exponentially and clinicians should consider this alternative option when managing patients with a contraindication to OAT. This review summarises the current thinking about LAAO.

Electronic health record-wide association study for atrial fibrillation in a British cohort

Background

Atrial fibrillation (AF) confers a major healthcare burden from hospitalisations and AF-related complications, such as stroke and heart failure. We performed an electronic health records-wide association study to identify the most frequent reasons for healthcare utilization, pre and post new-onset AF.

Methods

Prospective cohort study with the linked electronic health records of 5.6 million patients in the United Kingdom Clinical Practice Research Datalink (1998-2016). A cohort study with AF patients and their age-and sex matched controls was implemented to compare the top 100 reasons of frequent hospitalisation and primary consultation.

Results

Of the 199,433 patients who developed AF, we found the most frequent healthcare interactions to be cardiac, cerebrovascular and peripheral-vascular conditions, both prior to AF diagnosis (41/100 conditions in secondary care, such as cerebral infarction and valve diseases; and 33/100 conditions in primary care), and subsequently (47/100 conditions hospital care and 48 conditions in primary care). There was a high representation of repeated visits for cancer and infection affecting multiple organ systems. We identified 10 novel conditions which have not yet been associated with AF: folic acid deficiency, pancytopenia, idiopathic thrombocytopenic purpura, seborrheic dermatitis, lymphoedema, angioedema, laryngopharyngeal reflux, rib fracture, haemorrhagic gastritis, inflammatory polyneuropathies.

Conclusion

Our nationwide data provide knowledge and better understanding of the clinical needs of AF patients suggesting: (i) groups at higher risk of AF, where screening may be more cost-effective, and (ii) potential complications developing following new-onset AF that can be prevented through implementation of comprehensive integrated care management and more personalised, tailored treatment.

Clinical trial registration

NCT04786366.

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.

MANAGEMENT OF ATRIAL FIBRILLATION, VENTRICULAR ARRHYTHMIA, LEFT VENTRICULAR DYSFUNCTION, AND SUBSEQUENT CARDIOPATHOLOGIC EVALUATION IN AN ORANGUTAN (PONGO PYGMAEUS × ABELII)

A 37-yr-old male vasectomized hybrid orangutan (Pongo pygmaeus × abelii) was diagnosed with left ventricular dysfunction during a preventative health care examination. Treatment was initiated with carvedilol. The following year, this orangutan was evaluated for intermittent lethargy. Following observation of an irregular cardiac rhythm during an echocardiogram, a lead II electrocardiogram revealed atrial fibrillation and ventricular arrhythmia. Additional treatment included amiodarone, furosemide, spironolactone, clopidogrel, and aspirin. An improved activity level was noted, and follow-up testing showed restoration of a sinus rhythm, reduced frequency of ventricular arrhythmia, and improved left ventricular function. The orangutan died 27 mon after initial diagnosis of heart disease, and a complete necropsy was performed. This article describes successful diagnosis and management of structural and arrhythmic heart disease in an orangutan, emphasizing the role of cardiac disease screening and behavioral training in apes, as well as the value of matching thorough antemortem and postmortem cardiac evaluation.

Bioinformatic Identification of Potential RNA Alterations on the Atrial Fibrillation Remodeling from Human Pulmonary Veins

Atrial fibrillation (AF) is the most frequent persistent arrhythmia. Many genes have been reported as a genetic background for AF. However, most transcriptome analyses of AF are limited to the atrial samples and have not been evaluated by multiple cardiac regions. In this study, we analyzed the expression levels of protein-coding and long noncoding RNAs (lncRNAs) in six cardiac regions by RNA-seq. Samples were donated from six subjects with or without persistent AF for left atria, left atrial appendages, right atria, sinoatrial nodes, left ventricles, right ventricles, and pulmonary veins (PVs), and additional four right atrial appendages samples were collected from patients undergoing mitral valve replacement. In total, 23 AF samples were compared to 23 non-AF samples. Surprisingly, the most influenced heart region in gene expression by AF was the PV, not the atria. The ion channel-related gene set was significantly enriched upon analysis of these significant genes. In addition, some significant genes are cancer-related lncRNAs in PV in AF. A co-expression network analysis could detect the functional gene clusters. In particular, the cancer-related lncRNA, such as SAMMSON and FOXCUT, belong to the gene network with the cancer-related transcription factor FOXC1. Thus, they may also play an aggravating role in the pathogenesis of AF, similar to carcinogenesis. In the least, this study suggests that (1) RNA alteration is most intense in PVs and (2) post-transcriptional gene regulation by lncRNA may contribute to the progression of AF. Through the screening analysis across the six cardiac regions, the possibility that the PV region can play a role other than paroxysmal triggering in the pathogenesis of AF was demonstrated for the first time. Future research with an increase in the number of PV samples will lead to a novel understanding of the pathophysiology of AF.

Risk for Bleeding-Related Hospitalizations During Use of Amiodarone With Apixaban or Rivaroxaban in Patients With Atrial Fibrillation : A Retrospective Cohort Study

BACKGROUND

Amiodarone, the most effective antiarrhythmic drug in atrial fibrillation, inhibits apixaban and rivaroxaban elimination, thus possibly increasing anticoagulant-related risk for bleeding.

OBJECTIVE

For patients receiving apixaban or rivaroxaban, to compare risk for bleeding-related hospitalizations during treatment with amiodarone versus flecainide or sotalol, antiarrhythmic drugs that do not inhibit these anticoagulants' elimination.

DESIGN

Retrospective cohort study.

SETTING

U.S. Medicare beneficiaries aged 65 years or older.

PATIENTS

Patients with atrial fibrillation began anticoagulant use between 1 January 2012 and 30 November 2018 and subsequently initiated treatment with study antiarrhythmic drugs.

MEASUREMENTS

Time to event for bleeding-related hospitalizations (primary outcome) and ischemic stroke, systemic embolism, and death with or without recent (past 30 days) evidence of bleeding (secondary outcomes), adjusted with propensity score overlap weighting.

RESULTS

There were 91 590 patients (mean age, 76.3 years; 52.5% female) initiating use of study anticoagulants and antiarrhythmic drugs, 54 977 with amiodarone and 36 613 with flecainide or sotalol. Risk for bleeding-related hospitalizations increased with amiodarone use (rate difference [RD], 17.5 events [95% CI, 12.0 to 23.0 events] per 1000 person-years; hazard ratio [HR], 1.44 [CI, 1.27 to 1.63]). Incidence of ischemic stroke or systemic embolism did not increase (RD, -2.1 events [CI, -4.7 to 0.4 events] per 1000 person-years; HR, 0.80 [CI, 0.62 to 1.03]). The risk for death with recent evidence of bleeding (RD, 9.1 events [CI, 5.8 to 12.3 events] per 1000 person-years; HR, 1.66 [CI, 1.35 to 2.03]) was greater than that for other deaths (RD, 5.6 events [CI, 0.5 to 10.6 events] per 1000 person-years; HR, 1.15 [CI, 1.00 to 1.31]) (HR comparison: P = 0.003). The increased incidence of bleeding-related hospitalizations for rivaroxaban (RD, 28.0 events [CI, 18.4 to 37.6 events] per 1000 person-years) was greater than that for apixaban (RD, 9.1 events [CI, 2.8 to 15.3 events] per 1000 person-years) (P = 0.001).

LIMITATION

Possible residual confounding.

CONCLUSION

In this retrospective cohort study, patients aged 65 years or older with atrial fibrillation treated with amiodarone during apixaban or rivaroxaban use had greater risk for bleeding-related hospitalizations than those treated with flecainide or sotalol.

PRIMARY FUNDING SOURCE

National Heart, Lung, and Blood Institute.

Artificial Intelligence for the Detection and Treatment of Atrial Fibrillation

AF is the most common clinically relevant cardiac arrhythmia associated with multiple comorbidities, cardiovascular complications (e.g. stroke) and increased mortality. As artificial intelligence (AI) continues to transform the practice of medicine, this review article highlights specific applications of AI for the screening, diagnosis and treatment of AF. Routinely used digital devices and diagnostic technology have been significantly enhanced by these AI algorithms, increasing the potential for large-scale population-based screening and improved diagnostic assessments. These technologies have similarly impacted the treatment pathway of AF, identifying patients who may benefit from specific therapeutic interventions. While the application of AI to the diagnostic and therapeutic pathway of AF has been tremendously successful, the pitfalls and limitations of these algorithms must be thoroughly considered. Overall, the multifaceted applications of AI for AF are a hallmark of this emerging era of medicine.

Pharmacology and Clinical Development of Factor XI Inhibitors

Therapeutic anticoagulation is indicated for a variety of circumstances and conditions in several fields of medicine to prevent or treat venous and arterial thromboembolism. According to the different mechanisms of action, the available parenteral and oral anticoagulant drugs share the common principle of hampering or blocking key steps of the coagulation cascade, which unavoidably comes at the price of an increased propensity to bleed. Hemorrhagic complications affect patient prognosis both directly and indirectly (ie, by preventing the adoption of an effective antithrombotic strategy). Inhibition of factor XI (FXI) has emerged as a strategy with the potential to uncouple the pharmacological effect and the adverse events of anticoagulant therapy. This observation is based on the differential contribution of FXI to thrombus amplification, in which it plays a major role, and hemostasis, in which it plays an ancillary role in final clot consolidation. Several agents were developed to inhibit FXI at different stages (ie, suppressing biosynthesis, preventing zymogen activation, or impeding the biological action of the active form), including antisense oligonucleotides, monoclonal antibodies, small synthetic molecules, natural peptides, and aptamers. Phase 2 studies of different classes of FXI inhibitors in orthopedic surgery suggested that dose-dependent reductions in thrombotic complications are not paralleled by dose-dependent increases in bleeding compared with low-molecular-weight heparin. Likewise, the FXI inhibitor asundexian was associated with lower rates of bleeding compared with the activated factor X inhibitor apixaban in patients with atrial fibrillation, although no evidence of a therapeutic effect on stroke prevention is available so far. FXI inhibition could also be appealing for patients with other conditions, including end-stage renal disease, noncardioembolic stroke, or acute myocardial infarction, for which other phase 2 studies have been conducted. The balance between thromboprophylaxis and bleeding achieved by FXI inhibitors needs confirmation in large-scale phase 3 clinical trials powered for clinical end points. Several of such trials are ongoing or planned to define the role of FXI inhibitors in clinical practice and to clarify which FXI inhibitor may be most suited for each clinical indication. This article reviews the rationale, pharmacology, results of medium or small phase 2 studies, and future perspectives of drugs inhibiting FXI.

The Minimum Number of Ablation Lines for Complete Isolation of the Pulmonary Veins during Thoracoscopic Ablation for Atrial Fibrillation

Total thoracoscopic ablation has been recommended as a class IIa indication for atrial fibrillation. However, the optimal number of ablation lines for pulmonary vein isolation has not yet been proposed. This study aimed to report the minimum number of ablation lines required to achieve an intraoperative conduction block. This study included a total of 20 patients who underwent total thoracoscopic ablation from December 2020 to July 2021. The epicardial conduction block was checked after each ablation line of pulmonary vein antral clamping. The median age was 61 years old. The median duration of atrial fibrillation since the first diagnosis was 78 months. Pulmonary vein isolation with bidirectional conduction block was confirmed in 90% of patients. A median of six ablation lines around each pulmonary vein antrum were performed according to our protocol even after the conduction block was verified. The median number of ablations to achieve an exit block was two on the right side and 3.5 on the left side. We found that most conduction blocks were achieved within three ablations around the pulmonary vein antrum. Our results may provide evidence to reduce the number of unnecessary ablation lines in the future.