Current Evidence-Based Understanding of the Epidemiology, Prevention, and Treatment of Atrial Fibrillation

Long-term hyperuricemia impact on atrial fibrillation outcomes

BACKGROUND

No studies have been conducted to analyze the impact of serum uric acid (UA) levels on the outcome of atrial fibrillation (AF) patients. We aimed to evaluate the effect of hyperuricemia (HU) on the prognosis of AF.

METHODS AND RESULTS

Consecutive patients who consulted our emergency room for an episode of AF, already known or newly diagnosed, between January 1, 2010, and December 31, 2015 (n=2017) were enrolled. After applying exclusion criteria, 1772 patients were included. Serum UA levels in the 6 months before or after the date of the episode were recorded and classified into quartiles: Q1 (n=443) serum UA levels <4.6 mg/dL; Q2 (n=430) 4.6-5.6 mg/dL; Q3 (n=435) 5.7-6.9 mg/dL; and Q4 (n=464) ≥7 mg/dL. Two groups were differentiated: patients without HU (Q1-Q3) and those with HU (Q4). The mean follow-up was 3.7 ± 1.4 years. The primary endpoint was all-cause mortality during follow-up. Mortality during follow-up in the bivariate analysis was higher (p < 0.001) in patients with HU (52.1 %) compared to those without it (35.3 %), confirming multivariate Cox analysis of HU as an independent risk factor for death [hazard ratio 1.89 (1.59-2.25)]. Kaplan-Meier survival analysis showed a shorter survival time in patients with HU (log-rank test, p<0.001). Cox analysis confirmed significant differences in the risk of heart failure (30 % vs. 22 %) in patients with HU.

CONCLUSIONS

HU is independently associated with an increased risk for all-cause mortality and hospitalization for heart failure in patients with AF.

Dual vs Single Cardioversion of Atrial Fibrillation in Patients With Obesity: A Randomized Clinical Trial

Importance

Atrial fibrillation and obesity are common, and both are increasing in prevalence. Obesity is associated with failure of cardioversion of atrial fibrillation using a standard single set of defibrillator pads, even at high output.

Objective

To compare the efficacy and safety of dual direct-current cardioversion (DCCV) using 2 sets of pads, with each pair simultaneously delivering 200 J, with traditional single 200-J DCCV using 1 set of pads in patients with obesity and atrial fibrillation.

Design, Setting, and Participants

This was a prospective, investigator-initiated, patient-blinded, randomized clinical trial spanning 3 years from August 2020 to 2023. As a multicenter trial, the setting included 3 sites in Louisiana. Eligibility criteria included body mass index (BMI) of 35 or higher (calculated as weight in kilograms divided by height in meters squared), age 18 years or older, and planned nonemergent electrical cardioversion for atrial fibrillation. Patients who met inclusion criteria were randomized 1:1. Exclusions occurred due to spontaneous cardioversion, instability, thrombus, or BMI below threshold.

Interventions

Dual DCCV vs single DCCV.

Main Outcomes and Measures

Return to sinus rhythm, regardless of duration, immediately after the first cardioversion attempt of atrial fibrillation, adverse cardiovascular events, and chest discomfort after the procedure.

Results

Of 2079 sequential patients undergoing cardioversion, 276 met inclusion criteria and were approached for participation. Of these, 210 participants were randomized 1:1. After exclusions, 200 patients (median [IQR] age, 67.6 [60.1-72.4] years; 127 male [63.5%]) completed the study. The mean (SD) BMI was 41.2 (6.5). Cardioversion was successful more often with dual DCCV compared with single DCCV (97 of 99 patients [98%] vs 87 of 101 patients [86%]; P = .002). Dual cardioversion predicted success (odds ratio, 6.7; 95% CI, 3.3-13.6; P = .01). Patients in the single cardioversion cohort whose first attempt failed underwent dual cardioversion with all subsequent attempts (up to 3 total), all of which were successful: 12 of 14 after second cardioversion and 2 of 14 after third cardioversion. There was no difference in the rating of postprocedure chest discomfort (median in both groups = 0 of 10; P = .40). There were no cardiovascular complications.

Conclusions and Relevance

In patients with obesity (BMI ≥35) undergoing electrical cardioversion for atrial fibrillation, dual DCCV results in greater cardioversion success compared with single DCCV, without any increase in complications or patient discomfort.

Trial Registration

ClinicalTrials.gov Identifier: NCT04539158.

A novel tsRNA-5008a promotes ferroptosis in cardiomyocytes that causes atrial structural remodeling predisposed to atrial fibrillation

Atrial fibrillation (AF) is an extremely common clinical arrhythmia disease, but whether its mechanism is associated with ferroptosis remains unclear. The tRNA-derived small RNAs (tsRNAs) are involved in a variety of cardiovascular diseases, however, their role and mechanism in atrial remodeling in AF have not been studied. We aimed to explore whether tsRNAs mediate ferroptosis in AF progression. The AF models were constructed to detect ferroptosis-related indicators, and Ferrostatin-1 (Fer-1) was introduced to clarify the relationship between ferroptosis and AF. Atrial myocardial tissue was used for small RNA sequencing to screen potential tsRNAs. tsRNA functioned on ferroptosis and AF was explored. Atrial fibrosis and changes in the cellular structures and arrangement were observed in AF mice model, and these alterations were accompanied by ferroptosis occurrence, exhibited by the accumulation of Fe2+ and MDA levels and the decrease of expression of FTH1, GPX4, and SLC7A11. Blocking above ferroptosis activation with Fer-1 resulted in a significant improvement for AF. A total of 7 tsRNAs were upregulated (including tsRNA-5008a) and 2 tsRNAs were downregulated in atrial myocardial tissue in the AF group compared with the sham group. We constructed a tsRNA-mRNA regulated network, which showed tsRNA-5008a targeted 16 ferroptosis-related genes. Knockdown of tsRNA-5008a significantly suppressed ferroptosis through targeting SLC7A11 and diminished myocardial fibrosis both in vitro and in vivo. On the contrary, tsRNA-5008a mimics promoted ferroptosis in cardiomyocytes. Collectively, tsRNA-5008a involved in AF through ferroptosis. Our study provides novel insights into the role of tsRNA-5008a mediated ferroptosis in AF progression.

Impact of Bariatric Surgery on the Prevalence and Outcomes of Atrial Fibrillation in Obese Patients

Obesity has been identified as a significant factor contributing to the development of numerous cardiovascular conditions and as a result, the cardiovascular community has prioritized efforts to address obesity and reduce its associated risks. However, despite these efforts, the prevalence of obesity continues to rise steadily, and is projected to double in the upcoming years. Atrial fibrillation is among the most prevalent and extensively researched cardiovascular comorbidities associated with obesity. Several mechanisms have been postulated, including scar tissue formation and fat deposition, which ultimately leads to atrial remodeling and subsequent arrhythmogenesis. Numerous strategies have been implemented to prevent and manage obesity, encompassing lifestyle adjustments, dietary modifications, pharmacological treatments, and surgical interventions. Bariatric surgery has garnered significant recognition over the years due to its promising outcomes, including a decrease in the overall prevalence of atrial fibrillation and other cardiovascular comorbidities in general in obese patients. This study focuses on the current trends regarding the impact of bariatric surgery on obese patients with atrial fibrillation.

Atrial fibrillation and stroke: State-of-the-art and future directions

Atrial fibrillation (AF) and stroke remain a major cause of morbidity and mortality. The two conditions shared common co-morbidities and risk factors. AF-related strokes are associated with worse clinical outcomes and higher mortality compared to non-AF-related. Early detection of AF is vital for prevention. While various scores have been developed to predict AF in such a high-risk group, they are yet to incorporated into clinical guidelines. Novel markers and predictors of AF including coronary and intracranial arterial calcification have also been studied. There are also ongoing debates on the management of acute stroke in patients with AF, and those who experienced breakthrough stroke while on oral anticoagulants. We provided an overview of the complex interplay between AF and stroke, as well as the treatment and secondary prevention of stroke in AF. We also comprehensively discussed the current evidence and the ongoing conundrums, and highlighted the future directions on the topic.

Predictive value of HMGB1 for atrial fibrillation recurrence after cryoballoon ablation in paroxysmal atrial fibrillation patients

BACKGROUND

Cryoballoon ablation (CBA) is recommended for patients with symptomatic drug refractory paroxysmal atrial fibrillation (pAF). However, substantial atrial fibrillation (AF) recurrence is common during follow-up. Searching for a potential biomarker representing both myocardial injury and inflammation to identify patients at high risk of AF recurrence after CBA is very meaningful for postoperative management of AF patients.

HYPOTHESIS

To evaluate the clinical efficacy of high-mobility group box 1 (HMGB1) protein released from the left atrium to predict AF recurrence in pAF patients after CBA at 1-year follow-up.

METHODS

We included 72 pAF patients who underwent CBA. To determine the expression levels of HMGB1, left atrial blood samples were collected from the patients before CBA and after the procedure through the transseptal sheath. Patients were followed up for AF recurrence for 1 year.

RESULTS

A total of 19 patients of the 72 experienced AF recurrence. The level of postoperative HMGB1 (HMGB1post) was higher in the AF recurrence group than in the AF non recurrence group (p = .03). However, no differences were noted in the levels of other biomarkers such as preoperative high-sensitivity C-reactive protein (hs-CRP), postoperativehs-CRP, and preoperative HMGB1 between the two groups. Multiple logistic regression analysis revealed that a higher level of serum HMGB1post was associated with AF recurrence (odds ratio: 5.29 [1.17-23.92], p = .04). Receiver operating characteristic analysis revealed that HMGB1post had a moderate predictive power for AF recurrence (area under the curve: 0.68; sensitivity: 72%; and specificity: 68%). The 1-year AF-free survival was significantly lower in patients with a high HMGB1post level than in those with a low HMGB1post level (hazard ratio: 3.81 [1.49-9.75], p = .005).

CONCLUSION

In pAF patients who under went CBA, the level of HMGB1 after CBA was associated with AF recurrence and demonstrated a moderate predictive power. Thus, we offer a potential biomarker to identify pAF patients at high risk of AF recurrence.

Oral Anticoagulants in Very Elderly Nonvalvular Atrial Fibrillation Patients With High Bleeding Risks: ANAFIE Registry

BACKGROUND

Data on the effectiveness and safety of oral anticoagulant (OAC) agents in very elderly nonvalvular atrial fibrillation patients with high bleeding risk are lacking.

OBJECTIVES

This study examined 2-year outcomes and effects of OAC agents among these patients using the ANAFIE (All Nippon Atrial Fibrillation in the Elderly) registry (N = 32,275) data.

METHODS

Patients were classified into high-risk (age: ≥80 years; CHADS₂ score: ≥2; and presence of ≥1 bleeding risk factor: creatinine clearance of 15-30 mL/minute, prior bleeding at critical sites, body weight of ≤45 kg, or continuous antiplatelet use) and reference groups.

RESULTS

In the high-risk (n = 7,104) and reference (n = 25,171) group patients, 89.0% and 93.4%, respectively, used OAC agents. Of these, respectively, 30.1% and 24.2% used warfarin, and 58.9% and 69.1% used direct-acting OAC (DOAC) agents. Compared with the reference group, the high-risk group had higher incidences of stroke/systemic embolism, major bleeding, intracranial hemorrhage, gastrointestinal bleeding, cardiovascular events, and all-cause death. In the high-risk group, DOAC agent use vs nonuse of OAC agents was associated with reduced incidences of stroke/systemic embolism (HR: 0.53; 95% CI: 0.36-0.79) and all-cause death (HR: 0.65; 95% CI: 0.52-0.81) but not with major bleeding (HR: 1.09; 95% CI: 0.63-1.89). DOAC agents were superior to warfarin in effectiveness and safety. For high-risk patients, history of major bleeding, severe liver dysfunction, and falls within 1 year were independent risk factors for major bleeding.

CONCLUSIONS

High-risk elderly nonvalvular atrial fibrillation patients had higher event incidences. DOAC agents were associated with reduced risk of stroke/systemic embolism and all-cause death vs nonuse of OAC agents or warfarin. (Prospective Observational Study in Late-Stage Elderly Patients With Nonvalvular Atrial Fibrillation [ANAFIE registry]; UMIN000024006).

Serum Beta-2 Microglobulin: A Possible Biomarker for Atrial Fibrillation

BACKGROUND Atrial fibrillation (AF) is the most common persistent arrhythmia that can cause complications (including stroke). Therefore, its diagnosis and treatment require increased attention. Although beta-2 microglobulin (b2-MG) is a novel marker of cardiovascular disease, its role in AF has not been evaluated. MATERIAL AND METHODS We conducted a case-control study with 61 patients who had normal heart rhythm (control group) and 60 patients with AF (research group). We analyzed the serum b2-MG levels in both groups and performed multivariate analysis to assess the correlation between b2-MG and left atrial remodeling. In addition, b2-MG levels were compared between the left atrial blood and peripheral venous blood of another set of 57 patients with AF, who underwent cryoballoon ablation. RESULTS There were no statistically significant differences in the baseline characteristics (age, sex, history of hypertension, diabetes mellitus, previous stroke, coronary heart disease, and estimated glomerular filtration rate) of the control and research groups. The left atrial anteroposterior diameters (LAD) and left ventricular end-systolic diameters in the AF group were significantly larger compared to the control group (P<0.01). Serum ß2-MG levels in patients with AF were significantly higher (P<0.01) and positively correlated with the LAD (B-coefficient 25.482, 95% CI 14.410~36.554, P<0.01), serum ß2-MG levels in the left atrial blood were significantly higher than those in peripheral venous blood (P<0.01), and serum ß2-MG levels were an independent predictor of AF. CONCLUSIONS With the development of atrial fibrillation, the serum ß2-MG levels increase and are closely related to the left atrial remodeling due to AF. Therefore, ß2-MG can be an effective biomarker for predicting AF.

The role of atrial fibrillation catheter ablation in patients with heart failure

Atrial Fibrillation (AF) and heart failure (HF) with reduced ejection fraction (HFrEF) frequently coexist, resulting in significant morbidity and mortality. Therapeutic options for patients with AF and HFrEF are limited due to few antiarrhythmic drug (AAD) choices and historically equivocal effects of procedural interventions on mortality. However, recent randomized trials examining catheter ablation (CA) in AF patients with HFrEF have shown a beneficial effect on arrhythmic burden and HF symptoms, as well as an improvement in mortality. This review focuses on the role of CA for AF patients with HFrEF.

The efficacy and safety of amiodarone combined with beta-blockers in the maintenance of sinus rhythm for atrial fibrillation: A protocol for systematic review and network meta-analysis

BACKGROUND

The high recurrence rate of atrial fibrillation (AF) after recovering sinus rhythm has always been a clinical problem. Despite the established and widespread use of antiarrhythmic drugs, which one is better for maintaining sinus rhythm is still controversial. This study aims to summarize the randomized controlled trials (RCTs) of amiodarone combined with beta blockers to maintain sinus rhythm in AF, and to determine an effective and safe intervention for the prevention of AF recurrence through network meta-analysis (NMA).

METHODS AND ANALYSIS

A comprehensive search of the RCTs comparing amiodarone with different beta-blockers to maintain sinus rhythm of AF patients will be conducted from the inception to December 2019 in the Cochrane Library, PubMed, Web of Science, EMBASE, Chinese Biomedical Literature Database (SinoMed), Chinese National Knowledge Infrastructure (CNKI), and WanFang database. The primary outcomes will be the recurrence of AF and frequency of embolization complications. The secondary outcomes will be the symptom improvements and adverse events. Risk of bias assessment of the included RCTs will be conducted according to the Cochrane collaboration's risk of bias tool. Pairwise meta-analyses and Bayesian network meta-analyses will be performed for all related outcome measures. GRADE will be used to evaluate the quality of evidence.

RESULTS

The results of this NMA will be published in a peer-reviewed journal.

CONCLUSION

This NMA may provide more recommendations for patients and researchers, such as which treatment is better for a particular case of AF, and what may be the hotspots for the future studies.

PROSPERO REGISTRATION NUMBER

The protocol for this NMA has been registered on PROSPERO under the number CRD42020164438.

Does an imbalance in circulating vascular endothelial growth factors (VEGFs) cause atrial fibrillation in patients with valvular heart disease?

Background

The pathogenesis of atrial fibrillation (AF) remains unclear. Vascular endothelial growth factors (VEGFs) can stimulate fibrosis within the atrium and ventricle. We hypothesized that there is a relationship between the serum VEGFs/soluble vascular endothelial growth factor receptor (sVEGFRs) levels and AF in patients with valvular heart disease (VHD). This provides a new paradigm for studying AF.

Methods

The plasma levels of VEGF-A, VEGF-C, sVEGFR-1 and sVEGFR-2 were detected by enzyme-linked immunosorbent assay (ELISA). A total of 100 people, consisting of AF patients (long-standing, persistent AF; n=49), sinus rhythm (SR) patients (n=31) and healthy controls (n=20), were included in this study.

Results

The plasma levels of VEGF-A were significantly higher in AF patients compared to healthy control (P<0.05). The plasma levels of sVEGFR-1 were significantly higher in AF compared to SR (P<0.05). The plasma levels of sVEGFR-2 were significantly lower in AF patients compared to SR patients and healthy controls (both P<0.05). There was a significant and negative correlation between AF and the sVEGFR-2 levels in the groups (r=-0.432, P=0.000).

Conclusions

An imbalance in VEGFs and sVEGFRs may contribute to AF by breaking the balance of angiogenesis and lymphangiogenesis. Additionally, sVEGFR-2 may be an important biomarker of AF.