Outcomes Associated With Familial Versus Nonfamilial Atrial Fibrillation: A Matched Nationwide Cohort Study

Functional Analysis of Serum Long Noncoding RNAs in Patients with Atrial Fibrillation

Objectives

Long noncoding RNAs (lncRNAs) are closely related to diverse diseases. However, its role in atrial fibrillation (AF) pathogenesis needs further exploration.

Design

We performed microarray analysis on the serum samples from 70 healthy volunteers and 70 AF patients. This study was aimed at detecting the levels of serum lncRNAs and mRNAs and bioinformatically analyze them to establish potential marker(s) for AF diagnosis. Receiver operating curve (ROC) and area under the curve (AUC) were employed to address the AF diagnostic power of lncRNAs.

Results

In the AF serum samples, 753 lncRNAs and 802 mRNAs (p ≤ 0.05; fold change ≥ 2) were upregulated, and 315 lncRNAs and 153 mRNAs were downregulated, as opposed to healthy serum samples. Using bioinformatic analysis, we analyzed the top 4 differentially expressed (DE) lncRNAs, namely, NR-001587, NR-015407, NR-038455, and NR-038894, and found that the PI3K-AKT cell proliferation signaling pathway was most affected. This was in accordance with our functional analysis of DE mRNAs and adjacent lncRNAs. Notably, the elevated serum NR-001587 levels were strongly associated with AF incidence.

Conclusions

Our work highlights the role of lncRNAs in AF pathogenesis and provides a novel serum biomarker for AF diagnosis.

Rate of Heart Failure Following Atrial Fibrillation According to Presence of Family History of Dilated Cardiomyopathy or Heart Failure: A Nationwide Study

Background It is poorly understood why some patients with atrial fibrillation develop heart failure (HF) and others do not. We examined the rate of developing HF in patients with atrial fibrillation with and without first-degree family members with HF or dilated cardiomyopathy (DCM). Methods and Results Using Danish nationwide registries, patients born after 1942 diagnosed with atrial fibrillation in the period 2005 to 2015 were identified and followed for up to 5 years. Patients with pre-existing HF, DCM, and/or ischemic heart disease diagnoses were excluded. Exposure was defined as a first-degree relative with HF or DCM. The rate of developing the composite end point of HF or death, and the components, was estimated with multivariable Cox proportional hazard regression models. We included 10 605 patients. A total of 17% had a family member with DCM/HF. Having a family member with HF/DCM was associated with an increased 5-year risk of the composite of HF/death (cumulative incidence, 9.2% [95% CI, 7.8-10.7] versus 5.6% [95% CI, 5.0-6.1]; adjusted hazard ratio [HR] 1.36 [95% CI, 1.13-1.64]). (HF 8.4% [95% CI, 7.0-9.8] versus 4.5% [95% CI, 4.1-5.0]); (adjusted HR, 1.49 [95% CI, 1.22-1.82]). However, familial HF/DCM was not significantly associated with an increased 5-year risk and rate of death (0.8% [95% CI, 0.4-1.2] versus 1.1% [95% CI, 0.8-1.3]); (adjusted HR, 0.80 [95% CI, 0.46-1.39]). Conclusions In patients with incident atrial fibrillation without prior ischemic heart disease or HF diagnoses, 1 of 6 had a first-degree relative with HF, and having such a family history of HF/DCM was associated with an 87% increase in 5-year incidence of HF compared with those without.

Symptom burden and treatment perception in patients with atrial fibrillation, with and without a family history of atrial fibrillation

Atrial fibrillation (AF) is known to aggregate within family and might be associated with a lower quality-of-life (QoL). We evaluated the association between a family history (FHx) of AF and patient-reported symptom burden and perception towards treatment. We performed a retrospective analysis in a cohort of 1285 newly diagnosed patients with AF. Patients completed the atrial fibrillation effect on quality of life (AFEQT) questionnaire at the time of registration and at the 1-year follow-up. Patients who had a first-degree relative with AF were classified into the FHx group. Baseline characteristics and AFEQT scores were compared between groups, and a multivariate analysis was used to evaluate the independent association between FHx and QoL. Overall, 15.9% of patients (n = 204) had a positive AF FHx. Compared to the non-FHx group, the FHx group had an earlier onset of AF (60.2 ± 12.0 years vs. 64.5 ± 12.1 years; P < 0.05) and lower AFEQT overall summary (AFEQT-OS) score at baseline (73.9 ± 17.8 vs. 77.0 ± 16.8; P < 0.05). After adjustment for clinical background, a positive FHx was independently associated with a worse QoL (changes in AFEQT-OS score = - 3.18; 95% confidence interval: - 5.67 to - 0.69; P = 0.012). No between-group difference in AFEQT-OS scores was noted at the 1-year follow-up. An FHx of AF was associated with a lower QoL, which could be improved by therapeutic intervention in patients with AF. Recognizing the presence of an FHx of AF is important to predict patient's symptom load and treatment acceptance.

RNA sequencing profiling reveals key mRNAs and long noncoding RNAs in atrial fibrillation

Long noncoding RNAs (lncRNAs) are an emerging class of RNA species that could participate in some critical pathways and disease pathogenesis. However, the underlying molecular mechanism of lncRNAs in atrial fibrillation (AF) is still not fully understood. In the present study, we analyzed RNA-seq data of paired left and right atrial appendages from five patients with AF and other five patients without AF. Based on the gene expression profiles of 20 samples, we found that a majority of genes were aberrantly expressed in both left and right atrial appendages of patients with AF. Similarly, the dysregulated pathways in the left and right atrial appendages of patients with AF also bore a close resemblance. Moreover, we predicted regulatory lncRNAs that regulated the expression of adjacent protein-coding genes (PCGs) or interacted with proteins. We identified that NPPA and its antisense RNA NPPA-AS1 may participate in the pathogenesis of AF by regulating the muscle contraction. We also identified that RP11 - 99E15.2 and RP3 - 523K23.2 could interact with proteins ITGB3 and HSF2, respectively. RP11 - 99E15.2 and RP3 - 523K23.2 may participate in the pathogenesis of AF via regulating the extracellular matrix binding and the transcription of HSF2 target genes, respectively. The close association of the lncRNA-interacting proteins with AF further demonstrated that these two lncRNAs were also associated with AF. In conclusion, we have identified key regulatory lncRNAs implicated in AF, which not only improves our understanding of the lncRNA-related molecular mechanism underlying AF but also provides computationally predicted regulatory lncRNAs for AF researchers.

Family History of Atrial Fibrillation and Risk of Cardiovascular Events: A Multicenter Prospective Cohort Study

BACKGROUND

To investigate the association between family history of atrial fibrillation (AF) with cardiovascular events (CVEs), major adverse cardiac events (MACE), and cardiovascular mortality.

METHODS

Multicenter prospective observational cohort study including 1722 nonvalvular AF patients from February 2008 to August 2019 in Italy. Family history of AF was defined as the presence of AF in a first-degree relative: mother, father, sibling, or children. Primary outcome was a composite of CVEs including fatal/nonfatal ischemic stroke and myocardial infarction, and cardiovascular death. Second, we analyzed the association with major adverse cardiac event.

RESULTS

Mean age was 74.6±9.4 years; 44% of women. Family history of AF was detected in 368 (21.4%) patients, and 3.5% had ≥2 relatives affected by AF. Age of AF onset progressively decreased from patients without family history of AF, compared with those with single and multiple first-degree affected relatives (P<0.001). During a mean follow-up of 23.7 months (4606 patients/y) 145 CVEs (3.15%/y), 98 major adverse cardiac event (2.13%/y), and 57 cardiovascular deaths (0.97%/y) occurred. After adjustment for cardiovascular risk factors, family history of AF was associated with a higher risk of CVEs (hazard ratio, 1.524 [95% CI, 1.021-2.274], P=0.039), major adverse cardiac event (hazard ratio, 1.917 [95% CI, 1.207-3.045], P=0.006), and cardiovascular mortality (hazard ratio, 2.008 [95% CI, 1.047-3.851], P=0.036). Subgroup analysis showed that this association was modified by age, sex, and prior ischemic heart disease.

CONCLUSIONS

In a cohort of elderly patients with a high atherosclerotic burden, family history of AF is evident in >20% of patients and was associated with an increased risk for CVEs and mortality. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01882114.

The Genetic Puzzle of Familial Atrial Fibrillation

Atrial fibrillation (AF) is the most common clinical tachyarrhythmia. In Europe, AF is expected to reach a prevalence of 18 million by 2060. This estimate will increase hospitalization for AF to 4 million and 120 million outpatient visits. Besides being an independent risk factor for mortality, AF is also associated with an increased risk of morbidities. Although there are many well-defined risk factors for developing AF, no identifiable risk factors or cardiac pathology is seen in up to 30% of the cases. The heritability of AF has been investigated in depth since the first report of familial atrial fibrillation (FAF) in 1936. Despite the limited value of animal models, the advances in molecular genetics enabled identification of many common and rare variants related to FAF. The importance of AF heritability originates from the high prevalence of lone AF and the lack of clear understanding of the underlying pathophysiology. A better understanding of FAF will facilitate early identification of people at high risk of developing FAF and subsequent development of more effective management options. In this review, we reviewed FAF epidemiological studies, identified common and rare variants, and discussed their clinical implications and contributions to developing new personalized therapeutic strategies.

Association between KCNE1 G38S gene polymorphism and risk of atrial fibrillation: A PRISMA-compliant meta-analysis

BACKGROUND

Previous case-control studies on association between KCNE1 G38S polymorphism and risk of atrial fibrillation (AF) have been published but because of the conflicting results and small sample size of individual studies, the consolidated result is still controversial.

OBJECTIVES

The aim of this study was to explore the relationship between KCNE1 G38S polymorphism and risk of AF.

METHODS

We performed a comprehensive literature search on PubMed, Embase, OVID, Web of Science, Wan Fang, and CNKI databases up to March 10, 2017 in English and Chinese languages. Two of the authors individually extracted study data and assessed the study quality using Newcastle-Ottawa scale. Odds ratios (ORs) and 95% confidence intervals (CIs) were combined in different genetic models for evaluation using a random-effect model or fixed-effect model according to interstudy heterogeneity.

RESULTS

There were totally 14 independent case-control studies of 2810 patients and 3080 healthy controls included. Significant associations were found between KCNE1 G38S polymorphism and AF in overall population under all genetic models: allelic (OR: 1.34, 95% CI: 1.24-1.45, P < .001), homozygous (OR: 1.90, 95% CI: 1.61-2.24, P < .001), heterozygous (OR: 1.43, 95% CI: 1.21-1.68, P < .001), recessive (OR: 1.42, 95% CI: 1.20-1.69, P < .001), dominant genetic model (OR: 1.62, 95% CI: 1.39-1.89, P < .001). Subgroup analyses indicated similar association in Chinese and white.

CONCLUSIONS

The G38S polymorphism in the KCNE1 gene can significantly increase the risk of AF in both Chinese and white.

Familial clustering of atrial fibrillation and comparative longitudinal outcomes of familial and non-familial atrial fibrillation

Several studies have suggested that family history of atrial fibrillation (AF) is an important risk factor for AF, with several specific genetic regions now implicated through Genome Wide Association Studies. In addition, familial AF is associated with earlier age of onset and affects patients with fewer comorbid conditions than their non-familial counterparts. While those with familial AF have worse symptoms, all-cause mortality and risk of thromboembolic complications are similar among familial and non-familial AF patients.