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Objective: This study aimed to elucidate the molecular mechanisms by which BRD4 play a role in atrial fibrillation (AF)., Methods and Results: We used a discovery-driven approach to detect BRD4 expression in the atria of patients with AF and in various murine models of atrial fibrosis. We used a BRD4 inhibitor (JQ1) and atrial fibroblast (aFB)-specific BRD4-knockout mice to elucidate the role of BRD4 in AF. We further examined the underlying mechanisms using RNA-seq and ChIP-seq analyses in vitro, to identify key downstream targets of BRD4. We found that BRD4 expression is significantly increased in patients with AF, with accompanying atrial fibrosis and aFB differentiation. We showed that JQ1 treatment and shRNA-based molecular silencing of BRD4 blocked ANG-II-induced extracellular matrix production and cell-cycle progression in aFBs. BRD4-related RNA-seq and ChIP-seq analyses in aFBs demonstrated enrichment of a subset of promoters related to the expression of profibrotic and proliferation-related genes. The pharmacological inhibition of BRD4 in vivo or in aFB-specific BRD4-knockout in mice limited ANG-II-induced atrial fibrosis, atrial enlargement, and AF susceptibility., Conclusion: Our findings suggest that BRD4 plays a key role in pathological AF, at least partially by activating aFB proliferation and ECM synthesis. This study provides mechanistic insights into the development of BRD4 inhibitors as targeted antiarrhythmic therapies., Competing Interests: Declaration of competing interest None., (Copyright © 2024. Published by Elsevier B.V.)

Background: With population aging, the prevalence of both cancer and atrial fibrillation (AF) have increased. However, there is scarce epidemiological data concerning the comorbid state of cancer and AF in low- and middle-income countries, including China., Objective: We aimed to evaluate the site-, sex-, and age-specific profiles of cancer and AF comorbidities in Chinese populations., Methods: Data from the Shanghai Municipal Health Commission database between 2015 and 2020 were screened, covering all medical records of Shanghai residents with medical insurance. Site-specific cancer profiles were evaluated for the population with AF relative to the age- and sex-adjusted population of residents without AF. The sex distribution and peak age of cancer diagnosis were also assessed., Results: A total of 25,964,447 adult patients were screened. Among them, 22,185 patients presented cancers comorbid with AF (median 77, IQR 67-82 years of age; men: n=13,631, 61.44%), while 839,864 presented cancers without AF (median 67, IQR 57-72 years of age; men: n=419,020, 49.89%), thus yielding a higher cancer prevalence among residents with AF (8.27%) than among those without AF (6.05%; P<.001). In the population with AF, the most prevalent cancer type was lung cancer, followed by colorectal, male genital organ, stomach, breast, liver, bladder, thyroid, leukemia, and esophageal cancers. AF was associated with an average of nearly 1.4-fold (prevalence ratio [PR] 1.37, 95% CI 1.35-1.38) increased prevalence of cancer after adjusting for age and sex. For site-specific analyses, an increased prevalence of cancer in the population with AF was observed in 20 of 21 cancer sites. This increased prevalence was most prominent for nonsolid tumors, including multiple myeloma (PR 2.56, 95% CI 2.28-2.87), leukemia (PR 1.73, 95% CI 1.57-1.90), and non-Hodgkin lymphoma (PR 1.59, 95% CI 1.43-1.77); intrathoracic malignancies, including mediastinum (PR 2.34, 95% CI 1.89-2.90), lung (PR 1.64, 95% CI 1.59-1.69), and esophageal cancers (PR 1.41, 95% CI 1.28-1.56); bone and soft tissue neoplasms (PR 1.56, 95% CI 1.37-1.77); and kidney cancer (PR 1.53, 95% CI 1.36-1.72). Cancer prevalence in the population with AF relative to that in the population without AF was higher in men than in women in 14 of 18 cancer sites, and female predominance was only observed for thyroid cancer. The peak age of index cancer diagnosis was lower in the population with AF (age group: 70-74 years) than in that without AF (age group: 75-79 years), especially for specific cancer types, including thyroid, central nervous system, mediastinum, esophageal, bladder, and biliary cancers., Conclusions: Patients with AF are associated with increased prevalence, heightened male predominance, and younger peak age of cancer. Further studies are needed to determine whether early screening of specific cancers is cost-effective and beneficial for patients with AF., (©Mu Chen, Cheng Li, Jiwei Zhang, Xin Cui, Wenqi Tian, Peng Liao, Qunshan Wang, Jian Sun, Li Luo, Hong Wu, Yi-Gang Li. Originally published in JMIR Public Health and Surveillance (https://publichealth.jmir.org), 17.10.2023.)

As a new energy source for atrial fibrillation ablation, electric pulse ablation has higher tissue selectivity and biosafety, so it has a great application prospect. At present, there is very limited research on multi-electrode simulated ablation of histological electrical pulse. In this study, a circular multi-electrode ablation model of pulmonary vein will be built on COMSOL5.5 platform for simulation research. The results show that when the voltage amplitude reaches about 900 V, it can make some positions achieve transmural ablation, and the depth of continuous ablation area formed can reach 3 mm when the voltage amplitude reaches 1 200 V. When the distance between catheter electrode and myocardial tissue is increased to 2 mm, a voltage of at least 2 000 V is required to make the depth of continuous ablation area reach 3 mm. Through the simulation of electric pulse ablation with ring electrode, the research results of this project can provide reference for the voltage selection in the clinical application of electric pulse ablation.

Background: Pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (AF) is associated with a non-negligible long-term recurrence rate., Objectives: The purpose of this study was to investigate whether PVI combined with 6 short ablation lines on the PVI circumferences (PVI+6L group) yields higher success rates than PVI alone (PVI group)., Methods: In this multicenter, single-blind, randomized trial, a total of 390 patients with paroxysmal AF were randomly assigned to the PVI group (n = 193) or the PVI+6L group (n = 197). The primary endpoint was freedom from AF/atrial tachycardia recurrence between 91 and 365 days. Secondary endpoints included AF burden, procedural parameters, and complications., Results: Freedom from atrial tachyarrhythmia was achieved in 160 of 197 patients (81.2%) in the PVI+6L group and 142 of 193 patients (73.6%) in the PVI group (hazard ratio 0.61; 95% confidence interval 0.39-0.97; P = .040). Mean AF burden tended to be lower in the PVI+6L group compared to the PVI group (1.95% vs 0.53%, P = .097). Procedural and ablation times were slightly longer in the PVI+6L group than in the PVI group (130 ± 25 minutes vs 121 ± 28 minutes; P = .002; and 46 ± 14 minutes vs 41 ± 16 minutes, P = .001, respectively). X-ray exposure was similar (60 ± 54 seconds vs 61 ± 60 seconds; P = .964). Complications occurred in 3 patients (1.6%) in the PVI group and 3 patients (1.5%) in the PVI+6L group., Conclusion: In patients with paroxysmal AF undergoing catheter ablation, adding 6 short ablation lines on the PVI circumferences could reduce the AF recurrence rate., (Copyright © 2021 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Atrial fibrillation (AF) is the most common cardiac arrhythmia nowadays. The occurrence of AF is closely associated with obesity. Cadherin-11 (Cad-11), as a member of the cadherin family, can make a contribution to diet-induced obesity and it will be informative to know whether Cad-11 exerts its effects on atrial remodeling and AF vulnerability in a diet-induced obesity model. In this study, we demonstrated that the expression of Cad-11 was significantly upregulated in the left atrium of AF patients with obesity and mice following 16 weeks of high-fat diet (HFD) feeding. Further confirmed that Cad-11 could regulate the activity of atrial fibroblasts by participating in inducing proinflammatory cytokines production. At animal levels, we found that although there was a lack of statistical difference in body weight, Cad-11 -/- mice could markedly improve impaired glucose tolerance and hyperlipidemia. Adverse atrial structural remodeling, including atrial enlargement, inflammation, and fibrosis provoked by HFD feeding were mitigated in Cad-11 -/- mice. Mechanistically, Cad-11 activated mitogen-activated protein kinases and nuclear factor-κB for interleukin-6 production in atrial fibroblasts that may contribute to the atrial fibrosis process in obesity-related AF, suggesting Cad-11 might be a new therapeutic target for obesity-related AF., (© 2021 Wiley Periodicals LLC.)

At present, the standard left atrial appendage occlusion procedure mainly involves two-dimensional imaging methods such as X-ray fluoroscopy and transesophageal echocardiography to guide the operation, which will lead to underestimation of the three dimensional structure of the left atrial appendage and the surrounding tissue, thus adversely affects the surgery. To solve this problem, a surgery assist system for left atrial appendage occlusion based on preoperative cardiac CT images is developed. The proposed system realizes the left atrial appendage parameter measurement based on cardiac CT image, and realizes the calculation of optimal delivery sheath trajectory and three-dimensional simulation of the delivery sheath movement on the basis of a novel delivery sheath trajectory model. The system is expected to provide precise guidance for left atrial appendage occlusion, improve the success rate and safety of the operation, and at the same time help reduce the difficulty of learning the operation, and facilitate the promotion of left atrial appendage occlusion.

Introduction: It is the common clinical practice to prescribe indefinite aspirin for patients with non-valvular atrial fibrillation (NVAF) post left atrial appendage occlusion (LAAO). However, aspirin as a primary prevention strategy for cardiovascular diseases has recently been challenged due to increased risk of bleeding. Therefore, aspirin discontinuation after LAAO in atrial fibrillation (ASPIRIN LAAO) trial is designed to assess the uncertainty about the risks and benefits of discontinuing aspirin therapy at 6 months postimplantation with a Watchman LAAO device in NVAF patients., Methods and Analysis: The ASPIRIN LAAO study is a prospective, multicentre, randomised, double-blinded, placebo-controlled non-inferiority trial. Patients implanted with a Watchman device within 6 months prior to enrollment and without pre-existing conditions requiring long-term aspirin therapy according to current guidelines are eligible for participating the trial. Subjects will be randomised in a 1:1 allocation ratio to either the Aspirin group (aspirin 100 mg/day) or the control group (placebo) at 6 months postimplantation. A total of 1120 subjects will be enrolled from 12 investigational sites in China. The primary composite endpoint is stroke, systemic embolism, cardiovascular/unexplained death, major bleeding, acute coronary syndrome and coronary or periphery artery disease requiring revascularisation at 24 months. Follow-up visits are scheduled at 6 and 12 months and then every 12 months until 24 months after the last patient recruitment., Ethics and Dissemination: Ethics approval was obtained from the Ethics Committee of Xinhua Hospital, Shanghai, China (reference number XHEC-C-2018-065-5). The protocol is also submitted and approved by the institutional Ethics Committee at each participating centre. Results are expected in 2024 and will be disseminated through peer-reviewed journals and presentations at national and international conferences., Trial Registration Number: NCT03821883., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Both atrial fibrillation (AF) and early repolarization (ER) are highly prevalent in patients with Wolff-Parkinson-White (WPW) syndrome., Methods: We retrospectively identified 123 WPW patients with manifest accessory pathway (mAP) and 105 patients with concealed accessory pathways (cAP) who underwent successful ablation of the APs. AF history prior to the ablation was investigated. The presence of ER was evaluated from the 12-lead electrocardiograms performed both before and immediately after the ablation. Patients were further followed up for AF occurrence after the AP ablation., Results: Compared with cAP patients, WPW patients presented with higher incidence of previous AF, as well as ER after the AP ablation. Compared with those without AF history, WPW patients with comorbid AF were more prone to presenting ER, especially in the inferior leads, after the mAP ablation. Regression analysis suggested that the post-ablation ER in the inferior leads was strongly associated with AF in WPW patients [OR = 5.85; 95% confidence interval (CI): 2.29-14.96], even after adjusting for age and left atrial diameter (OR = 5.14; 95% CI: 1.80-14.74). Moreover, post-ablation inferior-lead ER was predictive of AF recurrence after mAP ablation during the follow-up of 22.6 ± 11.1 months. In comparison, ER was correlated with neither AF history nor AF recurrence in patients undergoing cAP ablation., Conclusions: ER in the inferior leads after the mAP ablation is highly correlated with AF history and recurrence in WPW patients., (Copyright © 2019. Published by Elsevier Ltd.)

Angiotensin II (Ang-II)-induced fibroblast differentiation plays an important role in the development of atrial fibrosis and atrial fibrillation (AF). Here, we show that the expression of the histone methyltransferase enhancer of zeste homolog 2 (EZH2) is increased in atrial muscle and atrial fibroblasts in patients with AF, accompanied by significant atrial fibrosis and atrial fibroblast differentiation. In addition, EZH2 is induced in murine models of atrial fibrosis. Furthermore, either pharmacological GSK126 inhibition or molecular silencing of EZH2 can inhibit the differentiation of atrial fibroblasts and the ability to produce ECM induced by Ang-II. Simultaneously, inhibition of EZH2 can block the Ang-II-induced migration of atrial fibroblasts. We found that EZH2 promotes fibroblast differentiation mainly through the Smad signaling pathway and can form a transcription complex with Smad2 to bind to the promoter region of the ACTA2 gene. Finally, our in vivo experiments demonstrated that the EZH2 inhibitor GSK126 significantly inhibited Ang-II-induced atrial enlargement and fibrosis and reduced AF vulnerability. Our results demonstrate that targeting EZH2 or EZH2-regulated genes might present therapeutic potential in AF., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Purpose: Previous studies showed that genetic variants of the angiotensinogen (AGT) gene conferred higher risk for acquired atrial fibrillation (AF). The present study investigated whether AGT variants correlate with the clinical outcome in patients with acquired AF after catheter ablation (CA)., Methods: A total of 150 acquired symptomatic drug-refractory AF patients (mean age 63.7±11.0 years, 24.6% non-paroxysmal AF) with acquired AF underwent a single CA procedure in our department and were included in this retrospective analysis. Eight tagging single nucleotide polymorphisms (tSNPs) in the AGT gene were genotyped. Standard electrocardiographs (ECGs) and 24-hour Holter recordings were performed during a median follow-up period of 57.5 months to detect AF recurrence., Results: Sixty-one patients (40.7%) suffered AF recurrences after a single CA procedure during follow up. Of the eight tSNPs, the frequency of the M allele of M235T was significantly higher in the recurrence group (28%) compared to the non-recurrence group (18%) (p=0.042). The recurrence rates of patients with the TT, MT, and MM genotypes were 34.4%, 50%, and 55.6%, respectively (ptrend=0.049). After adjusting for age, sex, body mass index, hypertension, left atrial volume index (LAVI) and other covariates, M235T increased the risk of AF recurrence in additive and dominant models with odds ratios of 2.023 (95% confidence interval (CI): 1.034-3.926, p=0.033) and 2.601 (95% CI: 1.102-6.056, p=0.025), respectively. However, in multiple correction analyses, the p values of multiple comparisons were not statistically significant (pcorrect>0.05)., Conclusions: The M allele of M235T might be associated with an increased risk of AF recurrence after CA. Genotyping may thus be helpful on identifying patients with higher risks of AF recurrence after CA and developing optimal follow-up strategies. These strategies may differ and should be individualized according to patients' genotype. Future studies are warranted to validate the potential effect of AGT M235T on AF recurrence post CA., (© The Author(s) 2015.)

Objective: To investigate the association between CHADS2 score and long-term ( ≥ 3 years) outcomes post catheter ablation in patients with atrial fibrillation (AF)., Methods: AF patients who received single catheter ablation in our hospital from January 2004 to March 2009 in our department were included and patients received regular follow-up. AF recurrence was defined as the occurrence of atrial arrhythmias (AF, atrial flutter and atrial tachycardia) recorded by electrocardiogram monitor ( ≥ 30 seconds) after ablation during follow-up period (after 3 months blanking period). The relationship between baseline clinical and echocardiographic characteristics and the time to recurrence during follow-up was evaluated using Cox multivariate analysis., Results: A total of 280 patients who received single catheter ablation procedure were included in the study, 3 patients died and there were 50 patients lost to follow-up. A total of 227 patients with AF (163 paroxysmal and 64 non-paroxysmal ) were enrolled in the final analysis. During a median follow-up of 51 months (41-56 months), 109 patients experienced AF recurrences and the recurrence rate after catheter ablation ( ≥ 3 years) was 48.0% (109/227). Cox multivariate analysis showed that the high CHADS2 score (HR: 1.417, 95%CI 1.194-1.682, P < 0.001) and AF non-termination during ablation (HR: 2.077, 95%CI 1.380-3.126, P = 0.043) were risk factors of AF recurrence. AF recurrence rates in the termination and non-termination group were 41.0% (75/183) and 77.3% (34/44), respectively. In the AF termination group, the recurrence rates and the median recurrence free time in patients with CHADS2 score ≥ 3 were 80.0% (12/15) and 1 year, respectively. In the non-AF termination group, the recurrence rates in patients with CHADS2 score = 0, CHADS2 score = 1-2 and CHADS2 score ≥ 3 were 60.0% (6/10), 77.8% (21/27) and 100% (7/7), respectively; the median recurrence free time of patients with CHADS2 score = 0, CHADS2 score = 1-2 and CHADS2 score ≥ 3 were 30 months, 12 months and 6 months, respectively., Conclusions: CHADS2 score is a predictor of AF recurrences after catheter ablation. Patients with high CHADS2 score is associated with higher risk of long-term ( ≥ 3 years) AF recurrences.

A distributed simulation method of electric field based on the atrial defibrillation of the heart modeling and finite element solution is proposed in this study. In order to solve the problem that ordinary clinical trials could not measure the actual distribution of the defibrillation electric field in the heart accurately, this method provides a research tool for electrical defibrillation. A complete atrial anatomical structure in the heart model is used in the research, the finite element method is proceeded to solve; Three parameters: defibrillation threshold voltage, the high field strength rate and the defibrillation threshold energy are set to evaluate the effect of defibrillation. The heart electric field distributions of transvenous atrial defibrillation with different electrode locations or sizes are simulated. The simulation results and the reported results match fairly well, which initially verify the feasibility of this method.

Aims: Bronchi or pulmonary arteries (PAs) could be injured during atrial fibrillation (AF) ablation. Therefore, the aim of the present study was to evaluate the spatial relationship between left atrial roof or superior pulmonary veins (PVs) and neighbouring structures of AF patients and provide anatomic guidance for AF ablation to avoid injuring bronchi or PAs., Methods and Results: A dual-source computed tomography (DSCT) scan was used to depict the left atrium (LA), PVs, and nearby structures including bronchi and PAs in 58 patients with drug-refractory AF (mean age, 64 ± 9 years). The distance between LA roof or superior PVs (SPVs) and bronchi or PAs was measured. The average minimal distances from the left, middle, and right points of the LA roof to the principal bronchi were 17.0 ± 6.4, 23.7 ± 5.1, and 23.2 ± 7.7 mm, respectively. The LA roof was closer to the right PA (RPA) than the left PA (LPA) for more than 90% of patients. The average minimal distances from the left, middle, and right points of the LA roof to the PAs were 8.3 ± 5.0, 5.9 ± 3.1, and 6.0 ± 2.8 mm, respectively. The average minimal distances between the left superior pulmonary vein and bronchi or LPA were 0.32 ± 0.79 or 0.4 ± 1.0 mm, respectively. The average minimal distances between the right superior pulmonary vein and bronchi or RPA were 0.27 ± 0.94 and 0.0 ± 0.1 mm, respectively. Both of the root parts of SPVs of most patients were in direct contact with branches of trachea and PAs., Conclusion: Dual-source computed tomography provides important imaging information for determining the relationship between LA, PVs, and neighbouring structures. Use of pre-procedural cardiac CT scans may help avoid ablation-induced injury of bronchi and PAs.

Background: In most cell types, replicative senescence (RS) is supposed to be a principle causative factor for aging. Atrial fibrosis, pathologically characterized by proliferation of atrial fibroblasts (AFs) and excessive accumulation of extracellular matrix proteins, is the most common substrate of atrial fibrillation (Afib) in the elderly. However, whether AFs' RS develops in the aged and fibrotic left atrium (LA) and, if yes, what is the key regulator for the pathogenesis of AFs' RS remain largely unknown. Methods: We obtained the left atrial tissues from young (6– 8 weeks old) and aged (24 months old) C57BL/6 male mice. Screening and validation of differential genes were performed using comparative analysis of RNA-seq results. Replicative senescence was examined in primary AFs after cell passage. Further gain-of-function and loss-of-function experiments were performed to explore the regulation of the AFs' RS progression. Results: In the present study, we demonstrated that there was a considerable extent of AFs' RS in the aged and fibrotic LA. Transcriptome screening showed that Ezh2 (Enhancer of zeste homolog 2) was significantly downregulated in the LA tissue of aged mice. Ezh2 is a histone methyltransferase that catalyzes H3K27me3 and mediates transcriptional silencing. We confirmed that Ezh2 was downregulated in the isolated pure senescent AFs. Knockdown of Ezh2 by siRNA or inhibition of Ezh2ʹs methyltransferase activities by GSK-126 and GSK-343 accelerated RS in the early passage of AFs, while its overexpression deaccelerated RS in the late passage of AFs. Mechanistically, Ezh2 suppressed CDKN2a (p16, p19) and Timp4 gene transcription by forming canonical H3K27me3 modifications in their promoter regions. Furthermore, the functional balance between Timp4 and MMP8 in AFs could be collapsed by changes in Ezh2 expression. Conclusion: These results thus indicate that Ezh2 is a key regulator of AFs' RS and this work may provide a basis for future treatments for atrial fibrosis in the elderly. Graphical [ABSTRACT FROM AUTHOR]

Aims Bronchi or pulmonary arteries (PAs) could be injured during atrial fibrillation (AF) ablation. Therefore, the aim of the present study was to evaluate the spatial relationship between left atrial roof or superior pulmonary veins (PVs) and neighbouring structures of AF patients and provide anatomic guidance for AF ablation to avoid injuring bronchi or PAs. Methods and results A dual-source computed tomography (DSCT) scan was used to depict the left atrium (LA), PVs, and nearby structures including bronchi and PAs in 58 patients with drug-refractory AF (mean age, 64 ± 9 years). The distance between LA roof or superior PVs (SPVs) and bronchi or PAs was measured. The average minimal distances from the left, middle, and right points of the LA roof to the principal bronchi were 17.0 ± 6.4, 23.7 ± 5.1, and 23.2 ± 7.7 mm, respectively. The LA roof was closer to the right PA (RPA) than the left PA (LPA) for more than 90% of patients. The average minimal distances from the left, middle, and right points of the LA roof to the PAs were 8.3 ± 5.0, 5.9 ± 3.1, and 6.0 ± 2.8 mm, respectively. The average minimal distances between the left superior pulmonary vein and bronchi or LPA were 0.32 ± 0.79 or 0.4 ± 1.0 mm, respectively. The average minimal distances between the right superior pulmonary vein and bronchi or RPA were 0.27 ± 0.94 and 0.0 ± 0.1 mm, respectively. Both of the root parts of SPVs of most patients were in direct contact with branches of trachea and PAs. Conclusion Dual-source computed tomography provides important imaging information for determining the relationship between LA, PVs, and neighbouring structures. Use of pre-procedural cardiac CT scans may help avoid ablation-induced injury of bronchi and PAs. [ABSTRACT FROM PUBLISHER]

• The correlation between PM2.5 and different arrhythmias was found in this study. • The impact mode of PM2.5 for each type of arrhythmia was addressed in this study. • This study was performed in Shanghai, a city with serious air pollution problem. • The study was performed based on large-scale population data of over 200,000 ECGs. Recently, the impact of fine particulate matter pollution on cardiovascular system is drawing considerable concern worldwide. The association between ambient fine particulate and the cardiac arrhythmias is not clear now. To study associations of ambient fine particulate with incidence of arrhythmias in outpatients. Data was collected from the remote electrocardiogram (ECG) system covering 282 community hospitals in Shanghai from June 24th, 2014 to June 23rd, 2016. ECG was performed for patients admitted to above hospitals with complaining of chest discomfort or palpitation, or for regular check-ups. Air quality data during this time period was obtained from China National Environment Monitoring Center. A generalized additive quasi-Poisson model was established to examine the associations between PM2.5 and cardiac arrhythmias. Cardiac arrhythmias were detected in 202,661 out of 1,016,579 outpatients (19.9%) and fine particulate matter ranged from 6 to 219 μg/m3 during this period. Positive associations were evidenced between fine particulate matter level and prevalence of cardiac arrhythmia by different lag models. Per 10 μg/m3 increase in fine particulate matter was associated with a 0.584%(95%CI:0.346-0.689%, p < 0.001) increase of cardiac arrhythmia detected in these patient cohort at lag0-2. For different types of cardiac arrhythmias, an immediate arrhythmogenic effect of fine particulate matter (increase of the estimates of cardiac arrhythmia prevalence detected in daily outpatient visits) was found with paroxysmal supraventricular tachycardia; a lag effect was found with atrial fibrillation; and both immediate and lag effect was found with premature atrial contractions or atrial tachycardia, atrioventricular block. Moreover, the impact of fine particulate matter on cardiac arrhythmias was significantly greater in women (lag3 and lag0-4), and in people aged <65 years (lag0). Ambient exposure to fine particulate matter is linked with increased risk of arrhythmias in outpatients visiting Shanghai community hospitals, with an immediate or lag effect. The arrhythmogenic effect varies among different types of cardiac arrhythmias. [ABSTRACT FROM AUTHOR]