Family history of atrial fibrillation is associated with earlier-onset and more symptomatic atrial fibrillation: Results from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF) registry

Pathophysiology of Atrial Fibrillation and Approach to Therapy in Subjects Less than 60 Years Old

Atrial fibrillation (AF) is an arrhythmia that affects the left atrium, cardiac function, and the patients' survival rate. Due to empowered diagnostics, it has become increasingly recognized among young individuals as well, in whom it is influenced by a complex interplay of autoimmune, inflammatory, and electrophysiological mechanisms. Deepening our understanding of these mechanisms could contribute to improving AF management and treatment. Inflammation is a complexly regulated process, with interactions among various immune cell types, signaling molecules, and complement components. Addressing circulating antibodies and designing specific autoantibodies are promising therapeutic options. In cardiomyopathies or channelopathies, the first manifestation could be paroxysmal AF; persistent forms tend not to respond to antiarrhythmic drugs in these conditions. Further research, both in vitro and in vivo, on the use of genomic biotechnology could lead to new therapeutic approaches. Additional triggers that can be encountered in AF patients below 60 years of age are systemic hypertension, overweight, diabetes, and alcohol abuse. The aims of this review are to briefly report evidence from basic science and results of clinical studies that might explain the juvenile burden of the most encountered sustained supraventricular tachyarrhythmias in the general population.

Plasma growth differentiation factor-15 in patients with "lone" atrial fibrillation

Background

Growth differentiation factor‐15 (GDF‐15) is a member of the transforming growth factor β superfamily, correlated with various stimuli, including cardiovascular disease. The association between plasma GDF‐15 level and “lone” AF, that is, AF of unknown etiology (UeAF), is uncertain.

Methods

All patients aged 60 years or younger. AF patients were hospitalized for primary catheter ablation. Patients with sinus rhythm admitted for other diseases during the same period were included in the control group. ELISA was used to measure plasma GDF‐15 concentrations.

Results

60 UeAF patients, 60 paroxysmal AF (PAF) patients, and 70 control patients were enrolled. The mean age was 44.6 years. In the UeAF group, no patients had traditional clinical risk factors. The plasma GDF‐15 level in the UeAF group was (1028.5 ± 180.5) pg/ml, higher than in the control group, and moderately lower than in the PAF group. In all patients, positive correlations were found between plasma GDF‐15 level and age (R = 0.210, p < 0.05), and between plasma GDF‐15 level and left atrial diameter (LAD; R = 0.338, p < 0.05; in the UeAF group: R = 0.475, p < 0.05; in the PAF group: R = 0.504, p < 0.05).

Conclusions

Our study first investigated the role of GDF‐15 in UeAF. The plasma GDF‐15 level in UeAF patients was higher than in sinus rhythm patients and lower than in PAF patients. Moreover, GDF‐15 was positively correlated with age and LAD. The role of GDF‐15 in UeAF needs further study.

Whole-exome sequencing reveals a rare missense variant in DTNA in an Iranian pedigree with early-onset atrial fibrillation

Atrial fibrillation (AF) is a morbid and heritable irregular cardiac rhythm that affects about 2%–3% of the population. Patients with early-onset AF have a strong genetic association with the disease; nonetheless, the exact underlying mechanisms need clarification. We herein present our evaluation of a 2-generation Iranian pedigree with early-onset AF. Whole-exome sequencing was applied to elucidate the genetic predisposition. Direct DNA sequencing was utilized to confirm and screen the variants in the proband and his available family members. The pathogenicity of the identified nucleotide variations was scrutinized via either segregation analysis in the family or in silico predictive software. The comprehensive variant analysis revealed a missense variant (c.G681C, p.E227D, rs1477078144) in the human α-dystrobrevin gene (DTNA), which is rare in genetic databases. Most in silico analyses have predicted this variant as a disease-causing variant, and the variant is co-segregated with the disease phenotype in the family. Previous studies have demonstrated the association between the DTNA gene and left ventricular noncompaction cardiomyopathy. Taken together, we provide the first evidence of an association between a nucleotide variation in the DTNA gene and early-onset AF in an Iranian family. However, the genetic testing of AF in the Iranian population is still limited. This finding not only further confirms the significant role of genetics in the incidence of early-onset AF but also expands the spectrum of the gene variations that lead to AF. Additionally, it may have further implications for the treatment and prevention of AF.

Joint efficacy of the three biomarkers SNCA, GYPB and HBG1 for atrial fibrillation and stroke: Analysis via the support vector machine neural network

Atrial fibrillation (AF) is the most common type of persistent arrhythmia. Although its incidence has been increasing, the pathogenesis of AF in stroke remains unclear. In this study, a total of 30 participants were recruited, including 10 controls, 10 patients with AF and 10 patients with AF and stroke (AF + STROKE). Differentially expressed genes (DEGs) were identified, and functional annotation of DEGs, comparative toxicogenomic database analysis associated with cardiovascular diseases, and predictions of miRNAs of hub genes were performed. Using RT‐qPCR, biological process and support vector machine neural networks, numerous DEGs were found to be related to AF. HBG1, SNCA and GYPB were found to be upregulated in the AF group. Higher expression of hub genes in AF and AF + STROKE groups was detected via RT‐PCR. Upon training the biological process neural network of SNCA and GYPB for HBG1, only small differences were detected. Based on the support vector machine, the predicted value of SNCA and GYPB for HBG1 was 0.9893. Expression of the hub genes of HBG1, SNCA and GYPB might therefore be significantly correlated to AF. These genes are involved in the incidence of AF complicated by stroke, and may serve as targets for early diagnosis and treatment.

GARFIELD-AF risk score for mortality, stroke and bleeding within 2 years in patients with atrial fibrillation

Aims

To determine whether the Global Anticoagulant Registry in the FIELD–Atrial Fibrillation (GARFIELD-AF) integrated risk tool predicts mortality, non-haemorrhagic stroke/systemic embolism, and major bleeding for up to 2 years after new-onset AF and to assess how this risk tool performs compared with CHA₂DS₂-VASc and HAS-BLED.

Methods and results

Potential predictors of events included demographic and clinical characteristics, choice of treatment, and lifestyle factors. A Cox proportional hazards model was identified for each outcome by least absolute shrinkage and selection operator methods. Indices were evaluated in comparison with CHA₂DS₂-VASc and HAS-BLED risk predictors. Models were validated internally and externally in ORBIT-AF and Danish nationwide registries. Among the 52 080 patients enrolled in GARFIELD-AF, 52 032 had follow-up data. The GARFIELD-AF risk tool outperformed CHA₂DS₂-VASc for all-cause mortality in all cohorts. The GARFIELD-AF risk score was superior to CHA₂DS₂-VASc for non-haemorrhagic stroke, and it outperformed HAS-BLED for major bleeding in internal validation and in the Danish AF cohort. In very low- to low-risk patients [CHA₂DS₂-VASc 0 or 1 (men) and 1 or 2 (women)], the GARFIELD-AF risk score offered strong discriminatory value for all the endpoints when compared to CHA₂DS₂-VASc and HAS-BLED. The GARFIELD-AF tool also included the effect of oral anticoagulation (OAC) therapy, thus allowing clinicians to compare the expected outcome of different anticoagulant treatment decisions [i.e. no OAC, non-vitamin K antagonist (VKA) oral anticoagulants, or VKAs].

Conclusions

The GARFIELD-AF risk tool outperformed CHA₂DS₂-VASc at predicting death and non-haemorrhagic stroke, and it outperformed HAS-BLED for major bleeding in overall as well as in very low- to low-risk group patients with AF.

Clinical trial registration

URL: http://www.clinicaltrials.gov. Unique identifier for GARFIELD-AF: NCT01090362, ORBIT-AF I: NCT01165710; ORBIT-AF II: NCT01701817.

Role of genetics in atrial fibrillation management

Atrial fibrillation (AF) management has significantly improved during the career of professor Crijns. Research was implemented into guidelines and clinical practice. However, despite advances in AF management, large differences between individual treatment responses still exist and the mechanisms underlying initiation and perpetuation of AF are not completely understood. International collaborations have revealed the genetic contribution to AF and steps towards improving AF management are being made. In this short review, the most important paradigms shifts in the field of AF genetics are recognized and the future role of genetics in personalized management of AF is discussed.

Effect of family history of atrial fibrillation on recurrence after atrial fibrillation ablation: A report from the Chinese Atrial Fibrillation Registry Study

BACKGROUND

To evaluate the impact of family history of atrial fibrillation (FAF) on postablation atrial tachyarrhythmia (AT) recurrence.

METHODS

All the 8198 patients undergoing initial AF ablation registered in the Chinese Atrial Fibrillation Registry study were analyzed. FAF was defined as having first-degree relatives diagnosed as AF at age 65 years or younger, and before the time the case in this study was diagnosed. Cox proportional hazards models were used to evaluate the impact of FAF on postablation AT recurrence. Age, sex, body mass index, AF type, history of congestive heart failure, hypertension, diabetes mellitus, prior stroke/transient ischemic attack/systemic embolism, vascular diseases, use of contact force-sensing catheter, and completion of high school were adjusted. The definition of AT recurrence was any documented AF, atrial flutter, or AT lasting more than or equal to 30 s after 3 months blanking period.

RESULTS

After a mean follow-up of 26.2 ± 19.6 months, 318 out of the 645 patients (49.3%) with FAF and 3339 out of the 7553 patients (44.2%) without FAF experienced AT recurrence, corresponding to annual recurrence rates of 22.8% and 20.2%, respectively. Patients with FAF had a significant higher risk of AT recurrence (adjusted hazard ratio 1.129, 95% confidence interval 1.005-1.267) in multivariable analysis. Moreover, FAF had a significant higher impact on AT recurrence in the subgroup of patients diagnosed with AF at age 50 years or younger (p for interaction = .036).

CONCLUSION

FAF is a risk factor for postablation AT recurrence. This is especially true in those with AF diagnosed at 50 years or younger.

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.

Genetic Susceptibility for Atrial Fibrillation in Patients Undergoing Atrial Fibrillation Ablation

BACKGROUND

Ablation is a widely used therapy for atrial fibrillation (AF); however, arrhythmia recurrence and repeat procedures are common. Studies examining surrogate markers of genetic susceptibility to AF, such as family history and individual AF susceptibility alleles, suggest these may be associated with recurrence outcomes. Accordingly, the aim of this study was to test the association between AF genetic susceptibility and recurrence after ablation using a comprehensive polygenic risk score for AF.

METHODS

Ten centers from the AF Genetics Consortium identified patients who had undergone de novo AF ablation. AF genetic susceptibility was measured using a previously described polygenic risk score (N=929 single-nucleotide polymorphisms) and tested for an association with clinical characteristics and time-to-recurrence with a 3 month blanking period. Recurrence was defined as >30 seconds of AF, atrial flutter, or atrial tachycardia. Multivariable analysis adjusted for age, sex, height, body mass index, persistent AF, hypertension, coronary disease, left atrial size, left ventricular ejection fraction, and year of ablation.

RESULTS

Four thousand two hundred seventy-six patients were eligible for analysis of baseline characteristics and 3259 for recurrence outcomes. The overall arrhythmia recurrence rate between 3 and 12 months was 44% (1443/3259). Patients with higher AF genetic susceptibility were younger (P<0.001) and had fewer clinical risk factors for AF (P=0.001). Persistent AF (hazard ratio [HR], 1.39 [95% CI, 1.22-1.58]; P<0.001), left atrial size (per cm: HR, 1.32 [95% CI, 1.19-1.46]; P<0.001), and left ventricular ejection fraction (per 10%: HR, 0.88 [95% CI, 0.80-0.97]; P=0.008) were associated with increased risk of recurrence. In univariate analysis, higher AF genetic susceptibility trended towards a higher risk of recurrence (HR, 1.08 [95% CI, 0.99-1.18]; P=0.07), which became less significant in multivariable analysis (HR, 1.06 [95% CI, 0.98-1.15]; P=0.13).

CONCLUSIONS

Higher AF genetic susceptibility was associated with younger age and fewer clinical risk factors but not recurrence. Arrhythmia recurrence after AF ablation may represent a genetically different phenotype compared to AF susceptibility.

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.

Risk of Stroke in Patients With Atrial Fibrillation Is Associated With Stroke in Siblings: A Nationwide Study

Background

It remains unclear whether heritable factors can contribute to risk stratification for ischemic stroke in patients with atrial fibrillation (AF). We examined whether having a sibling with ischemic stroke was associated with increased risk of ischemic stroke and mortality in patients with AF.

Methods and Results

In this nationwide study of the Swedish population, patients with AF and their siblings were identified from the Swedish patient registers and the Swedish MGR (Multi‐Generation Register). Ischemic stroke events were retrieved from the Swedish patient registers and CDR (Cause of Death Register). Risk of ischemic stroke was compared between patients with AF with and without a sibling affected by ischemic stroke, AF, or both ischemic stroke and AF. The total study population comprised 113 988 subjects (mean age, 60±12 years) diagnosed with AF between 1989 and 2012. In total, 11 709 of them were diagnosed with a first ischemic stroke and 20 097 died during a mean follow‐up time of 5.5 years for ischemic stroke and 5.9 years for mortality. After adjustment for covariates having a sibling with ischemic stroke, or both ischemic stroke and AF, was associated with increased risk of ischemic stroke (hazard ratio, 1.31; 95% CI, 1.23–1.40 or hazard ratio, 1.36; 95% CI, 1.24–1.49, respectively). Furthermore, ischemic stroke in a sibling was associated with all‐cause mortality (hazard ratio, 1.09; 95% CI, 1.05–1.14). In contrast, the risk of stroke was only marginally increased for patients with AF with a spouse affected by ischemic stroke.

Conclusions

Having a sibling affected by ischemic stroke confers an increased risk of ischemic stroke and death independently of traditional risk factors in patients with AF.

Characteristics of Atrial Fibrillation Patients with a Family History of Atrial Fibrillation

Background

Family history has been shown to be associated with increased risk of atrial fibrillation (AF). However, the specific AF characteristics that travel with a family history have not yet been elucidated. The purpose of this study was to determine whether a family history of AF is associated with specific patient characteristics in a worldwide, remote cohort.

Methods

From the Health eHeart Study, an internet-based prospective cohort, we performed a cross-sectional analysis of AF participants who reported their family history and completed questionnaires regarding their medical conditions and AF symptoms. We assessed demographics, cardiovascular comorbidities, and AF symptom characteristics in AF participants with and without a family history of AF.

Results

In multivariable analysis of 5,884 participants with AF (mean age 59.9 ± 14.5, 59% male, 92% white), female sex (odds ratio [OR]=1.35, 95% CI, 1.17-1.54, p<0.0001) and birth in the U.S. (OR=2.54, 95% CI, 2.12-3.05, p<0.0001) were independently associated with having a family history of AF. Having a family history of AF was also more commonly associated with symptoms of shortness of breath (OR=1.40, 95% CI, 1.07-1.82, p=0.014), chest pain, pressure, or discomfort (OR=1.95, 95% CI, 1.22-3.13, p=0.0052), and feeling generally "off" about oneself (OR=1.84, 95% CI, 1.27-2.67, p=0.0013).

Conclusions

Patients with a family history of AF are more likely to be female, be US-born, and experience symptoms of AF, suggesting underlying mechanistic differences between those with and without family history of AF.

Parental Atrial Fibrillation and Stroke or Atrial Fibrillation in Young Adults

Background and Purpose- Cryptogenic strokes are often the first clinical manifestation of undiagnosed atrial fibrillation (AF). We designed this study to test whether parental AF is a risk factor for stroke in young adults. Methods- Population-based cohort study using linked administrative databases from April 1, 1972 to March 31, 2016 in Manitoba, Canada for 325 333 offspring (age ≥18 years) with at least 1 linked parent (total 582 195 parents). We examined the association between parental history of AF and stroke or transient ischemic attack (TIA) in the offspring using multivariable Cox proportional hazards models. Results- Offspring median age at study entry was 18 years. During 5.533 million person-years of follow-up (mean 17 years), 8678 offspring had an incident stroke or TIA (5.2% of the 24 583 offspring with a parental history of AF compared with 2.5% of the 300 750 offspring with no parental history of AF), and 1430 were diagnosed with AF (1.9% versus 0.3%). Incidence rates for stroke/TIA were higher in offspring with a parental history of AF (195.0 versus 156.6 per 100 000 person-years). Parental AF was associated with elevated risk in offspring of stroke/TIA (hazard ratio 1.11; 95% CI, 1.04-1.18) or AF (hazard ratio 1.75; 95% CI, 1.55-1.97) and a higher frequency of other cardiovascular risk factors. After adjusting for demographics, region of residence, socioeconomic status, and other stroke risk factors in offspring, parental AF was associated with AF in their offspring in young adulthood (adjusted hazard ratio 1.61; 95% CI, 1.43-1.82); the association of parental AF with offspring stroke/TIA was attenuated (adjusted hazard ratio 1.05; 95% CI, 0.99-1.12) after adjusting for the other cardiovascular risk factors. Conclusions- Parental AF is associated with increased risk of AF and other cardiovascular risk factors in their offspring during early adulthood, resulting in increased stroke risk.

Association of a Family History of Atrial Fibrillation With Incidence and Outcomes of Atrial Fibrillation: A Population-Based Family Cohort Study

Importance

The heritability of atrial fibrillation (AF), the contribution of genetic and environmental factors, and the association of a family history of AF with prognosis are unclear.

Objectives

To measure genetic and environmental factors in the familial aggregation of AF and to estimate the association of a family history of AF with major adverse cardiovascular events (MACE).

Design, Setting, and Participants

In this Taiwanese nationwide population-based study among more than 23 million people, a custom data set was obtained using the data of all patients having a diagnosis of AF recorded between January 1996 and December 2013 in the Taiwan National Health Insurance Research Database. The study population comprised all 23 422 955 individuals registered with the database in 2013, of whom 177 770 had a diagnosis of AF and were included in the heritability estimation. From the latter, a subgroup of patients having newly diagnosed AF with a first-degree relative affected by AF between 2000 and 2010 were selected and matched 1:4 to controls without a family history for estimating MACE-free survival. The dates of analysis were January 2010 to December 2013.

Main Outcomes and Measures

The prevalence and relative risk of AF in relatives of patients with AF, as well as the relative contributions of heritability and shared and nonshared environmental factors to AF susceptibility. Also measured was MACE-free survival after AF was diagnosed.

Results

In total, 1510 patients (204 [13.5%] female; mean [SD] age, 57.9 [9.2] years) had newly diagnosed AF with a first-degree relative affected by AF. Individuals with a first-degree relative affected by AF had a relative risk of 1.92 (95% CI, 1.84-1.99) for AF. The accountability for the phenotypic variance of AF was 19.9% for genetic factors (heritability), 3.5% for shared environmental factors, and 76.6% for nonshared environmental factors. After matching for age, sex, hypertension, type 2 diabetes, previous stroke, and anticoagulation, incident AF patients with vs without an affected first-degree relative had similar MACE-free survival.

Conclusions and Relevance

Genetic and environmental factors were associated with AF, with nonshared environmental factors accounting for three-fourths of the phenotypic variance in Taiwan. Patients having AF with a first-degree relative affected by AF did not have more MACE. Therefore, family history may not be particularly informative in the diagnosis or management of AF.

A comprehensive meta-analysis on relationship between CYP11B2 rs1799998 polymorphism and atrial fibrillation

BACKGROUND

The correlation between CYP11B2 rs1799998 polymorphism and atrial fibrillation (AF) was analyzed by several studies, but the results of these studies were inconsistent. Thus, we performed this study to obtain a more conclusive result on relationship between CYP11B2 rs1799998 polymorphism and AF.

METHODS

Eligible studies were searched in PubMed, Medline and Embase. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to estimate the strength of correlation.

RESULTS

A total of 12 studies with 5466 participants were analyzed. We found that CYP11B2 rs1799998 polymorphism was significantly associated with AF in overall population under recessive genetic model with FEM (P = 0.005, OR = 1.29, 95%CI 1.08-1.54), but no positive results were detected in overall analyses with REMs. Further subgroup analyses revealed that CYP11B2 rs1799998 polymorphism was significantly correlated with AF in East Asians, but not in West Asians. Furthermore, significant associations between rs1799998 polymorphism and AF were observed in subjects with essential hypertension (EH) and heart failure (HF). No any other positive results were found in overall and subgroup analyses.

CONCLUSIONS

Overall, our meta-analysis suggested that rs1799998 polymorphism may serve as a potential biological marker of AF in East Asians and subjects with EH or HF.

Association Between Family History and Early-Onset Atrial Fibrillation Across Racial and Ethnic Groups

Importance

There is a genetic predisposition to early-onset atrial fibrillation (EOAF) in European American individuals. However, the role of family history in the pathogenesis of EOAF in racial and ethnic minorities remains unclear.

Objective

To determine whether probands with EOAF across racial and ethnic groups have a higher rate of AF in first-degree family members than racially and ethnically matched control patients with non-early-onset AF (non-EOAF).

Design, Setting, and Participants

In this cohort study, patients prospectively enrolled in a clinical and genetic biorepository were administered baseline questionnaires that included questions about family history of AF. Early-onset AF was defined as AF occurring in probands aged 60 years or younger in the absence of structural heart disease. All other forms were categorized as non-EOAF. Recruitment took place from July 2015 to December 2017. Analysis was performed in January 2018.

Main Outcomes and Measures

Primary analysis of reported family history of AF in first-degree relatives with sensitivity analysis restricted to those in whom a family history was confirmed by medical record review and electrocardiogram.

Results

Of 664 patients enrolled (mean [SD] age, 62 [12] years; 407 [61%] male), 267 (40%) were European American; 258 (39%), African American; and 139 (21%), Hispanic/Latino. There was a family history of AF in 36 probands with EOAF (49%) compared with 128 patients with non-EOAF (22%) (difference, 27%; 95% CI, 14%-40%; P < .001). On multivariable analysis, the adjusted odds of a proband with EOAF who was of African descent (odds ratio [OR], 2.69; 95% CI, 1.06-6.91; P < .001) or Hispanic descent (OR, 9.25; 95% CI, 2.37-36.23; P = .002) having a first-degree relative with AF were greater than those of European descent (OR, 2.51; 95% CI, 1.29-4.87; P = .006). Overall, probands with EOAF were more likely to have a first-degree relative with AF compared with patients with non-EOAF (adjusted OR, 3.02; 95% CI, 1.82-4.95; P < .001) across the 3 racial and ethnic groups. Atrial fibrillation in a first-degree family member was confirmed in 32% of probands with EOAF vs 11% of those with non-EOAF (difference, 21%; 95% CI, 11%-33%; P < .001). Furthermore, African American (28% vs 5%; difference, 23%; 95% CI, 4%-43%; P = .001), European American (35% vs 20%; difference, 15%; 95% CI, 1%-30%; P = .03), and Hispanic/Latino (30% vs 5%; difference, 25%; 95% CI, 4%-54%; P = .02) probands with EOAF were more likely to have a first-degree relative with confirmed AF vs racially and ethnically matched control patients with non-EOAF. The positive and negative predictive values for a family history of confirmed AF were both 89%.

Conclusions and Relevance

Probands of African or Hispanic/Latino descent with EOAF were more likely to have a first-degree relative with AF when compared with European American individuals. These findings support genetic predisposition to EOAF across all 3 races.

Improved risk stratification of patients with atrial fibrillation: an integrated GARFIELD-AF tool for the prediction of mortality, stroke and bleed in patients with and without anticoagulation

OBJECTIVES

To provide an accurate, web-based tool for stratifying patients with atrial fibrillation to facilitate decisions on the potential benefits/risks of anticoagulation, based on mortality, stroke and bleeding risks.

DESIGN

The new tool was developed, using stepwise regression, for all and then applied to lower risk patients. C-statistics were compared with CHA₂DS₂-VASc using 30-fold cross-validation to control for overfitting. External validation was undertaken in an independent dataset, Outcome Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF).

PARTICIPANTS

Data from 39 898 patients enrolled in the prospective GARFIELD-AF registry provided the basis for deriving and validating an integrated risk tool to predict stroke risk, mortality and bleeding risk.

RESULTS

The discriminatory value of the GARFIELD-AF risk model was superior to CHA₂DS₂-VASc for patients with or without anticoagulation. C-statistics (95% CI) for all-cause mortality, ischaemic stroke/systemic embolism and haemorrhagic stroke/major bleeding (treated patients) were: 0.77 (0.76 to 0.78), 0.69 (0.67 to 0.71) and 0.66 (0.62 to 0.69), respectively, for the GARFIELD-AF risk models, and 0.66 (0.64-0.67), 0.64 (0.61-0.66) and 0.64 (0.61-0.68), respectively, for CHA₂DS₂-VASc (or HAS-BLED for bleeding). In very low to low risk patients (CHA₂DS₂-VASc 0 or 1 (men) and 1 or 2 (women)), the CHA₂DS₂-VASc and HAS-BLED (for bleeding) scores offered weak discriminatory value for mortality, stroke/systemic embolism and major bleeding. C-statistics for the GARFIELD-AF risk tool were 0.69 (0.64 to 0.75), 0.65 (0.56 to 0.73) and 0.60 (0.47 to 0.73) for each end point, respectively, versus 0.50 (0.45 to 0.55), 0.59 (0.50 to 0.67) and 0.55 (0.53 to 0.56) for CHA₂DS₂-VASc (or HAS-BLED for bleeding). Upon validation in the ORBIT-AF population, C-statistics showed that the GARFIELD-AF risk tool was effective for predicting 1-year all-cause mortality using the full and simplified model for all-cause mortality: C-statistics 0.75 (0.73 to 0.77) and 0.75 (0.73 to 0.77), respectively, and for predicting for any stroke or systemic embolism over 1 year, C-statistics 0.68 (0.62 to 0.74).

CONCLUSIONS

Performance of the GARFIELD-AF risk tool was superior to CHA₂DS₂-VASc in predicting stroke and mortality and superior to HAS-BLED for bleeding, overall and in lower risk patients. The GARFIELD-AF tool has the potential for incorporation in routine electronic systems, and for the first time, permits simultaneous evaluation of ischaemic stroke, mortality and bleeding risks.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier for GARFIELD-AF (NCT01090362) and for ORBIT-AF (NCT01165710).

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.

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

Background

We examined all‐cause mortality and long‐term thromboembolic risk (ischemic stroke, transient ischemic attack, systemic thromboembolism) in patients with and without familial atrial fibrillation (AF).

Methods and Results

Using Danish nationwide registry data, we identified all patients diagnosed with AF (1995–2012) and divided them into those with familial AF (having a first‐degree family member with a prior AF admission) and those with nonfamilial AF. We paired those with and without familial AF according to age, year of AF diagnosis, and sex in a 1:1 match. Using cumulative incidence and multivariable Cox models, we examined the risk of long‐term outcomes. We identified 8658 AF patients (4329 matched pairs) with and without familial AF. The median age was 50 years (interquartile range 43–54 years), and 21.4% were women. Compared with nonfamilial AF patients, those with familial AF had slightly less comorbid illness but similar overall CHA₂DS₂‐VASc score (P=0.155). Median follow‐up was 3.4 years (interquartile range 1.5–6.5 years). Patients with familial AF had risk of death and thromboembolism similar to those with nonfamilial AF (adjusted hazard ratio 0.91 [95% CI 0.79–1.04] for death and 0.90 [95% CI 0.71–1.14] for thromboembolism).

Conclusions

Although family history of AF is associated with increased likelihood for development of AF, once AF developed, long‐term risks of death and thromboembolic complications were similar in familial and nonfamilial AF patients.