Atrial Fibrillation Is a Complex Trait: Very Complex

Clonal haematopoiesis of indeterminate potential and atrial fibrillation: an east Asian cohort study

BACKGROUND AND AIMS

Both clonal haematopoiesis of indeterminate potential (CHIP) and atrial fibrillation (AF) are age-related conditions. This study investigated the potential role of CHIP in the development and progression of AF.

METHODS

Deep-targeted sequencing of 24 CHIP mutations (a mean depth of coverage = 1000×) was performed in 1004 patients with AF and 3341 non-AF healthy subjects. Variant allele fraction ≥ 2.0% indicated the presence of CHIP mutations. The association between CHIP and AF was evaluated by the comparison of (i) the prevalence of CHIP mutations between AF and non-AF subjects and (ii) clinical characteristics discriminated by CHIP mutations within AF patients. Furthermore, the risk of clinical outcomes-the composite of heart failure, ischaemic stroke, or death-according to the presence of CHIP mutations in AF was investigated from the UK Biobank cohort.

RESULTS

The mean age was 67.6 ± 6.9 vs. 58.5 ± 6.5 years in AF (paroxysmal, 39.0%; persistent, 61.0%) and non-AF cohorts, respectively. CHIP mutations with a variant allele fraction of ≥2.0% were found in 237 (23.6%) AF patients (DNMT3A, 13.5%; TET2, 6.6%; and ASXL1, 1.5%) and were more prevalent than non-AF subjects [356 (10.7%); P < .001] across the age. After multivariable adjustment (age, sex, smoking, body mass index, diabetes, and hypertension), CHIP mutations were 1.4-fold higher in AF [adjusted odds ratio (OR) 1.38; 95% confidence interval 1.10-1.74, P < .01]. The ORs of CHIP mutations were the highest in the long-standing persistent AF (adjusted OR 1.50; 95% confidence interval 1.14-1.99, P = .004) followed by persistent (adjusted OR 1.44) and paroxysmal (adjusted OR 1.33) AF. In gene-specific analyses, TET2 somatic mutation presented the highest association with AF (adjusted OR 1.65; 95% confidence interval 1.05-2.60, P = .030). AF patients with CHIP mutations were older and had a higher prevalence of diabetes, a longer AF duration, a higher E/E', and a more severely enlarged left atrium than those without CHIP mutations (all P < .05). In UK Biobank analysis of 21 286 AF subjects (1297 with CHIP and 19 989 without CHIP), the CHIP mutation in AF is associated with a 1.32-fold higher risk of a composite clinical event (heart failure, ischaemic stroke, or death).

CONCLUSIONS

CHIP mutations, primarily DNMT3A or TET2, are more prevalent in patients with AF than non-AF subjects whilst their presence is associated with a more progressive nature of AF and unfavourable clinical outcomes.

Somatic Mutations in Cardiovascular Disease

Advances in population-scale genomic sequencing have greatly expanded the understanding of the inherited basis of cardiovascular disease (CVD). Reanalysis of these genomic datasets identified an unexpected risk factor for CVD, somatically acquired DNA mutations. In this review, we provide an overview of somatic mutations and their contributions to CVD. We focus on the most common and well-described manifestation, clonal hematopoiesis of indeterminate potential. We also review the currently available data regarding how somatic mutations lead to tissue mosaicism in various forms of CVD, including atrial fibrillation and aortic aneurism associated with Marfan Syndrome. Finally, we highlight future research directions given current knowledge gaps and consider how technological advances will enhance the discovery of somatic mutations in CVD and management of patients with somatic mutations.

Stroke Prevention Therapy and Prevalence of Risk Factors Among Patients With Atrial Fibrillation at King Fahad University Hospital in Al Khobar: A Retrospective, Single-Center Study

Background

Atrial fibrillation is the most common cardiac arrhythmia in clinical practice. It represents a significant health impact as it is greatly associated with increased risk of mortality and morbidity, most importantly stroke and systemic thromboembolism. 

Aim

This study aims to determine the risk factors of atrial fibrillation, to identify stroke and bleeding risk factors among patients with atrial fibrillation, to assess the trend of stroke prevention management and the influence of CHA2DS2-VASc and HAS-BLED scores on choosing the treatment.

Methods

This study was performed using all the medical records of 395 patients with Atrial fibrillation who were admitted between 2011-2019 at King Fahd University Hospital, Al-Khobar, Saudi Arabia. The review process included demographic data of the patients and the calculation of stroke and bleeding risk by CHA2DS2-VASc and HAS-BLED scores.

Results

The median age of the population was 72 years old. Hypertension was the most common risk factor for atrial fibrillation (78.2%), followed by diabetes mellitus (61.0%), dyslipidemia (60.0%), coronary artery disease (41.0%), myocardial infarction (18.7%), and congestive heart failure (29.4%). Regarding the management, (42.5%) of the patients were on a combination of both anticoagulants and antiplatelet therapy, while (33.2%) were on anticoagulant therapy only, (17.5%) were on antiplatelets only, and (5.8%) were not on medication. The increased use of anticoagulants and combined therapy was related to the percentage of a high-risk group of thromboembolic events reaching up to (34.5%) and (45.7%), respectively, which is statistically significant. Moreover, the prescription of warfarin declined in the last five years of our study, while the use of non-vitamin K antagonist oral anticoagulants increased.

Conclusion

Atrial fibrillation is more prevalent in females, hypertension was the most common risk factor for atrial fibrillation, followed by diabetes mellitus, and dyslipidemia. Most of the studied population was categorized as a high risk of stroke and bleeding according to CHA2DS2-VASc and HAS- BLED scores. The majority of the atrial fibrillation patient were taking anticoagulants and combined treatment as a stroke prevention therapy. Non-vitamin K antagonist oral anticoagulant prescription increased over warfarin in recent years.