Hypertension and atrial fibrillation: epidemiology, pathophysiology and therapeutic implications

Risk calculator for incident atrial fibrillation across a range of prediction horizons

BACKGROUND

The increasing burden of atrial fibrillation (AF) emphasizes the need to identify high-risk individuals for enrolment in clinical trials of AF screening and primary prevention. We aimed to develop prediction models to identify individuals at high-risk of AF across prediction horizons from 6-months to 10-years.

METHODS

We used secondary-care linked primary care electronic health record data from individuals aged ≥30 years without known AF in the UK Clinical Practice Research Datalink-GOLD dataset between January 2, 1998 and November 30, 2018; randomly divided into derivation (80%) and validation (20%) datasets. Models were derived using logistic regression from known AF risk factors for incident AF in prediction periods of 6 months, 1-year, 2-years, 5-years, and 10-years. Performance was evaluated using in the validation dataset with bootstrap validation with 200 samples, and compared against the CHA2DS2-VASc and C2HEST scores.

RESULTS

Of 2,081,139 individuals in the cohort (1,664,911 in the development dataset, 416,228 in the validation dataset), the mean age was 49.9 (SD 15.4), 50.7% were women, and 86.7% were white. New cases of AF were 7,386 (0.4%) within 6 months, 15,349 (0.7%) in 1 year, 38,487 (1.8%) in 5 years, and 79,997 (3.8%) by 10 years. Valvular heart disease and heart failure were the strongest predictors, and association of hypertension with AF increased at longer prediction horizons. The optimal risk models incorporated age, sex, ethnicity, and 8 comorbidities. The models demonstrated good-to-excellent discrimination and strong calibration across prediction horizons (AUROC, 95%CI, calibration slope: 6-months, 0.803, 0.789-0.821, 0.952; 1-year, 0.807, 0.794-0.819, 0.962; 2-years, 0.815, 0.807-0.823, 0.973; 5-years, 0.807, 0.803-0.812, 1.000; 10-years 0.780, 0.777-0.784, 1.010), and superior to the CHA2DS2-VASc and C2HEST scores. The models are available as a web-based FIND-AF calculator.

CONCLUSIONS

The FIND-AF models demonstrate high discrimination and calibration across short- and long-term prediction horizons in 2 million individuals. Their utility to inform trial enrolment and clinical decisions for AF screening and primary prevention requires further study.

Hyperuricemia as a Risk Factor in Hypertension among Patients with Very High Cardiovascular Risk

Hypertension remains a global threat to public health, affecting the worldwide population. It is one of the most common risk factors for cardiovascular disease. Today's treatments focus on creating a hypotensive effect. However, there is a constant search for additional factors to reduce the potential of developing hypertension complications. These factors may act as a parallel treatment target with a beneficial effect in specific populations. Some studies suggest that uric acid may be considered such a factor. This study investigated the potential effect of uric acid concentrations over 5 mg/dL on the incidence of hypertension complications among patients with very high cardiovascular risk. A total of 705 patients with hypertension and very high cardiovascular risk were selected and included in the analysis. The patients were divided and compared according to serum uric acid levels. The study showed a higher occurrence of heart failure (OR = 1.7898; CI: 1.2738-2.5147; p = 0.0008), atrial fibrillation (OR = 3.4452; CI: 1.5414-7.7002; p = 0.0026) and chronic kidney disease (OR = 2.4470; CI: 1.3746-4.3558; p = 0.0024) among individuals with serum uric acid levels over 5 mg/dL, males and those with a BMI > 25 kg/m2. These findings suggest that even serum uric acid concentrations over 5 mg/dL may affect the prevalence of hypertension-related complications among patients with very high cardiovascular risk.

Association between Hypertension and Atrial Fibrillation in Patients on Hemodialysis

This study aimed to evaluate the prevalence and the association between hypertension (HTN) and atrial fibrillation (AF) in hemodialysis (HD) patients. A chart review-based, cross-sectional study was conducted on HD patients who had received HD for at least 6 months. Demographic, hemodynamic, and laboratory data were retrieved from the BestCare system, and the main outcomes were blood pressure before and after dialysis, and the presence of AF. Our sample consisted of 304 HD patients; 162 (53%) were male, and the mean age was 63 ± 18 years. Sixty-eight (20%) had AF, of whom 44 (64.7%) were male, with a mean age of 73 ± 12 years. The risk of AF increased by 0.4 [odds ratio: 1.04; 95% confidence interval (CI): 1.02-1.06; P <0.001] for every year of age. Almost the entire sample (66.45%, n = 202) was hypertensive, and those patients had a mean age of 64 ± 17 years, and nearly one-third had a body mass index in the obese category (28.7%, n = 58). In addition, with every increase in the Charlson comorbidity index score by two points, there was a 40% increased risk of developing HTN (OR: 2.47; 95% CI: 1.17-5.18; P = 0.017). The risk factors for the development of HTN and AF in HD patients were found to be increasing age for AF and female sex for HTN. The presence of HTN and diabetes increased the risk of developing AF seven-fold after HD.

[Rehabilitation for atrial fibrillation : Impact on arrhythmia and cumulative risk factors]

BACKGROUND

Atrial fibrillation (AF) occurs in cardiovascular diseases but also in hyperthyroidism. The independent risk factors (RF) that are cumulatively the cause of AF include arterial hypertension, obesity, malnutrition, alcohol and tobacco consumption, lack of exercise, diabetes mellitus, and sleep-related breathing disorders. These cause and reinforce each other and are amplified by psychosocial RF. This also leads to morphological consequences such as atrial cardiomyopathy or diastolic heart failure (HFpEF). Therapy focuses on stroke prophylaxis through anticoagulation and rhythm or frequency control of the AF.

AIM

The risk factors of AF are presented here in detail. RF control must be included in the management of AF. Effective risk management should definitely include the patient's lifestyle.

RESULTS AND CONCLUSION

Although RF management can be integrated into the acute medical and outpatient treatment of AF, there is little scope to deal with the individual risk profile of individual patients. With the bio-psycho-social treatment approach, cardiological rehabilitation offers the opportunity to establish individual, lifestyle-oriented risk management and to achieve symptomatic improvement, decreased AF burden, better performance, and a better quality of life through correctly dosed training. Further studies to clarify the question of whether clinical endpoints such as hospitalization or morbidity and mortality are reduced by cardiac rehabilitation in AF are desirable.

Prevalence of atrial fibrillation in a regional Victoria setting, findings from the crossroads studies (2001-2003 and 2016-2018)

OBJECTIVE

To estimate the prevalence of atrial fibrillation (AF) in regional Victoria at two time points (2001-2003 and 2016-2018), and to assess the use of electrocardiogram rhythm strips in a rural, community-based study for AF investigation.

DESIGN

Repeated cross-sectional design involving survey of residents of randomly selected households and a clinic. Predictors of AF were assessed using Firth penalised logistic regression, as appropriate for rare events.

SETTING

Goulburn Valley, Victoria.

PARTICIPANTS

Household residents aged ≥16 years. Non-pregnant participants aged 18+ were eligible for the clinic.

MAIN OUTCOME MEASURES

Atrial fibrillation by 12 lead electrocardiogram (earlier study) or electrocardiogram rhythm strip (AliveCor® device) (recent study).

RESULTS

The age standardised prevalence of AF was similar between the two studies (1.6% in the 2001-2003 study and 1.8% in the 2016-2018 study, 95% confidence interval of difference -0.010, 0.014, p = 0.375). The prevalence in participants aged ≥65 years was 3.4% (1.0% new cases) in the recent study. Predictors of AF in the earlier study were male sex, older age and previous stroke, while in the recent study they were previous stroke and self-reported diabetes. AliveCor® traces were successfully classified by the in-built algorithm (91%) vs physician (100%).

CONCLUSION

The prevalence of AF among community-based participants in regional Victoria was similar to predominantly metropolitan-based studies, and was unchanged over time despite increased rates of risk factors. Electrocardiogram rhythm strip investigation was successfully utilised, and particularly benefited from physician overview.

Hypertension and atrial fibrillation

Hypertension is the most prevalent cardiovascular risk factor underlying atrial fibrillation and is present in up to 40% of patients with atrial fibrillation. Furthermore, attributable risk studies have shown that a history of hypertension contributes to up to 24% of incident atrial fibrillation. New data suggest that even early forms of hypertension (prehypertension and aortic stiffness) are associated with an increased risk of atrial fibrillation development. Hypertension and prehypertension are therefore critical mediators for the development of atrial fibrillation. Mechanisms for the association between hypertension and atrial fibrillation include diffuse electro-structural changes to the left atrium, driven by the haemodynamic and neurohormonal influences of hypertension and other, frequently coexisting, cardiovascular risk factors. Management of hypertension in atrial fibrillation should focus not only on blood pressure reduction but also on a comprehensive risk factor modification strategy. Such strategies have been shown to be associated with significant improvements in atrial fibrillation symptom burden as well as improved arrhythmia-free survival and reversal of the progression of atrial fibrillation. These strategies should focus on dietary modifications as well as prescribed exercise programmes involving a multidisciplinary team and patient-centred atrial fibrillation care. Risk factor management, supplemented by antihypertensive medications as needed, provides the optimum strategy for improving outcomes and even reversing the natural progression of atrial fibrillation in patients with hypertension.

Brain and cardiovascular-related changes are associated with aging, hypertension, and atrial fibrillation

PURPOSE

The neural pathways in which the brain regulates the cardiovascular system is via sympathetic and parasympathetic control of the heart and sympathetic control of the systemic vasculature. Various cortical and sub-cortical sites are involved, but how these critical brain regions for cardiovascular control are altered in healthy aging and other risk conditions that may contribute to cardiovascular disease is uncertain.

METHODS

Here we review the functional and structural brain changes in healthy aging, hypertension, and atrial fibrillation - noting their potential influence on the autonomic nervous system and hence on cardiovascular control.

RESULTS

Evidence suggests that aging, hypertension, and atrial fibrillation are each associated with functional and structural changes in specific areas of the central nervous system involved in autonomic control. Increased muscle sympathetic nerve activity (MSNA) and significant alterations in the brain regions involved in the default mode network are commonly reported in aging, hypertension, and atrial fibrillation.

CONCLUSIONS

Further studies using functional and structural magnetic resonance imaging (MRI) coupled with autonomic nerve activity in healthy aging, hypertension, and atrial fibrillation promise to reveal the underlying brain circuitry modulating the abnormal sympathetic nerve activity in these conditions. This understanding will guide future therapies to rectify dysregulation of autonomic and cardiovascular control by the brain.

Silencing of TLR4 Inhibits Atrial Fibrosis and Susceptibility to Atrial Fibrillation via Downregulation of NLRP3-TGF-β in Spontaneously Hypertensive Rats

Introduction. This study was aimed at exploring whether silencing of TLR4 could inhibit atrial fibrosis and susceptibility to atrial fibrillation (AF) by regulating NLRP3-TGF-β in hypertensive rats. Methods. Spontaneously hypertensive rats (SHRs) were transfected with either a virus containing TLR4-shRNA to downregulate TLR4 or an empty virus (vehicle) at the age of 14 weeks. Fibrosis of left atrium and susceptibility to AF were detected, and expression of NLRP3-TGF-β in left atrial tissue at 22 weeks of age was measured. Primary cardiac fibroblasts were transfected with TLR4-shRNA or scrambled vehicle and stimulated with angiotensin (Ang) II. Proliferation of cardiac fibroblasts and expression of NLRP3-TGF-β were detected. Results. Silencing of TLR4 reduced left atrial fibrosis and susceptibility to AF in SHRs and downregulated expression of NLRP3, TGF-β, and collagen I. In vitro, TLR4 silencing reduced proliferation of cardiac fibroblasts induced by Ang II as well as expression of NLRP3, TGF-β, and collagen I. Conclusion. Silencing of TLR4 can downregulate NLRP3-TGF-β to reduce atrial fibrosis and susceptibility to AF in SHRs.

Obstructive Sleep Apnea and Atrial Fibrillation

Atrial fibrillation (AF) is the most common arrhythmia, increasing with age and comorbidities. Obstructive sleep apnea (OSA) is a chronic sleep disorder more common in older men. It has been shown that OSA is linked to AF. Nonetheless, the prevalence of OSA in patients with AF remains unknown because OSA is significantly underdiagnosed. This review, including 54,271 patients, carried out a meta-analysis to investigate the association between OSA and AF. We also performed a meta-regression to explore cofactors influencing this correlation. A strong link was found between these two disorders. The incidence of AF is 88% higher in patients with OSA. Age and hypertension independently strengthened this association, indicating that OSA treatment could help reduce AF recurrence. Further research is needed to confirm these findings. Atrial Fibrillation (AF) is the most common arrhythmia, increasing with age and comorbidities. Obstructive sleep apnea (OSA) is a regulatory respiratory disorder of partial or complete collapse of the upper airways during sleep leading to recurrent pauses in breathing. OSA is more common in older men. Evidence exists that OSA is linked to AF. Nonetheless, the prevalence of OSA in patients with AF remains unknown because OSA is underdiagnosed. In order to investigate the incidence of AF in OSA patients, we carried out a meta-analysis including 20 scientific studies with a total of 54,271 subjects. AF was present in 4801 patients of whom 2203 (45.9%) had OSA and 2598 (54.1%) did not. Of a total of 21,074 patients with OSA, 2203 (10.5%) had AF and 18,871 (89.5%) did not. The incidence of AF was 88% higher in patients with OSA. We performed a meta-regression to explore interacting factors potentially influencing the occurrence of AF in OSA. Older age and hypertension independently strengthened this association. The clinical significance of our results is that patients with OSA should be referred early to the cardiologist. Further research is needed for the definition of the mechanisms of association between AF and OSA.

Renal denervation for atrial fibrillation: a comprehensive updated systematic review and meta-analysis

The study aims to compare clinical outcomes following renal denervation (RDN) in hypertensive patients with atrial fibrillation (AF). Three online databases were searched (MEDLINE, EMBASE and PubMed) for literature related to outcomes of RDN on hypertension and AF, between January 1, 2010, and June 1, 2021. Where possible, risk ratios (RR) and mean differences (MD) were combined using a random effects model. Significance was set at p ≤ 0.05. Seven trials were included that assessed the effect of adding RDN to pulmonary vein isolation (PVI) in patients with hypertension and AF. A total of 711 patients (329 undergoing PVI + RDN and 382 undergoing PVI alone), with an age range of 56 ± 6 to 68 ± 9 years, were included. Pooled analysis showed a significant lowering of AF recurrence in the PVI + RDN (31.3%) group compared to the PVI-only (52.9%) group (p < 0.00001). Pooled analysis of patients with resistant hypertension showed a significant mean reduction of systolic blood pressure (SBP) (-9.42 mm Hg, p = 0.05), but not diastolic blood pressure (DBP) (-4.11 mm Hg, p = 0.16) in favor of PVI + RDN. Additionally, the pooled analysis showed that PVI + RDN significantly improved estimated glomerular filtration rate (eGFR) (+10.2 mL/min per 1.73 m², p < 0.001) compared to PVI alone. RDN procedures in these trials have proven to be both safe and efficacious with an overall complication rate of 6.32%. Combined PVI and RDN is beneficial for patients with hypertension and AF. Combined therapy showed improvement in SBP and eGFR, reducing the risk of AF recurrence. RDN may serve as an innovative intervention in the treatment of AF.

Imaging techniques for the assessment of adverse cardiac remodeling in metabolic syndrome

Metabolic syndrome (MetS) includes different metabolic conditions (i.e. abdominal obesity, impaired glucose tolerance, hypertriglyceridemia, decreased HDL cholesterol, and/or hypertension) that concour in the development of cardiovascular disease and diabetes. MetS individuals often show adverse cardiac remodeling and myocardial dysfunction even in the absence of overt coronary artery disease or valvular affliction. Diastolic impairment and hypertrophy are hallmarks of MetS-related cardiac remodeling and represent the leading cause of heart failure with preserved ejection fraction (HFpEF). Altered cardiomyocyte function, increased neurohormonal tone, interstitial fibrosis, coronary microvascular dysfunction, and a myriad of metabolic abnormalities have all been implicated in the development and progression of adverse cardiac remodeling related to MetS. However, despite the enormous amount of literature produced on this argument, HF remains a leading cause of morbidity and mortality in such population. The early detection of initial adverse cardiac remodeling would enable the optimal implementation of effective therapies aiming at preventing the progression of the disease to the symptomatic phase. Beyond conventional imaging techniques, such as echocardiography, cardiac tomography, and magnetic resonance, novel post-processing tools and techniques provide information on the biological processes that underlie metabolic heart disease. In this review, we summarize the pathophysiology of MetS-related cardiac remodeling and illustrate the relevance of state-of-the-art multimodality cardiac imaging to identify and quantify the degree of myocardial involvement, prognosticate long-term clinical outcome, and potentially guide therapeutic strategies.

Molecules linked to Ras signaling as therapeutic targets in cardiac pathologies

Abstract

The Ras family of small Guanosine Triphosphate (GTP)-binding proteins (G proteins) represents one of the main components of intracellular signal transduction required for normal cardiac growth, but is also critically involved in the development of cardiac hypertrophy and heart failure. The present review provides an update on the role of the H-, K- and N-Ras genes and their related pathways in cardiac diseases. We focus on cardiac hypertrophy and heart failure, where Ras has been studied the most. We also review other cardiac diseases, like genetic disorders related to Ras. The scope of the review extends from fundamental concepts to therapeutic applications. Although the three Ras genes have a nearly identical primary structure, there are important functional differences between them: H-Ras mainly regulates cardiomyocyte size, whereas K-Ras regulates cardiomyocyte proliferation. N-Ras is the least studied in cardiac cells and is less associated to cardiac defects. Clinically, oncogenic H-Ras causes Costello syndrome and facio-cutaneous-skeletal syndromes with hypertrophic cardiomyopathy and arrhythmias. On the other hand, oncogenic K-Ras and alterations of other genes of the Ras-Mitogen-Activated Protein Kinase (MAPK) pathway, like Raf, cause Noonan syndrome and cardio-facio-cutaneous syndromes characterized by cardiac hypertrophy and septal defects. We further review the modulation by Ras of key signaling pathways in the cardiomyocyte, including: (i) the classical Ras-Raf-MAPK pathway, which leads to a more physiological form of cardiac hypertrophy; as well as other pathways associated with pathological cardiac hypertrophy, like (ii) The SAPK (stress activated protein kinase) pathways p38 and JNK; and (iii) The alternative pathway Raf-Calcineurin-Nuclear Factor of Activated T cells (NFAT). Genetic alterations of Ras isoforms or of genes in the Ras-MAPK pathway result in Ras-opathies, conditions frequently associated with cardiac hypertrophy or septal defects among other cardiac diseases. Several studies underline the potential role of H- and K-Ras as a hinge between physiological and pathological cardiac hypertrophy, and as potential therapeutic targets in cardiac hypertrophy and failure.

Graphic abstract

The Ras (Rat Sarcoma) gene family is a group of small G proteins

Ras is regulated by growth factors and neurohormones affecting cardiomyocyte growth and hypertrophy

Ras directly affects cardiomyocyte physiological and pathological hypertrophy

Genetic alterations of Ras and its pathways result in various cardiac phenotypes

Ras and its pathway are differentially regulated in acquired heart disease

Ras modulation is a promising therapeutic target in various cardiac conditions.

Detection of Atrial Fibrillation Using a Home Blood Pressure Monitor

PURPOSE

Atrial fibrillation (AF) is the most common arrhythmia and is associated with an increased risk of complications. A screening test has the potential to prevent AF-related complications. This study investigated the diagnostic accuracy of an automated device for home blood pressure (BP) monitoring, which implements an algorithm for AF detection.

PATIENTS AND METHODS

A modified, automated oscillometric device for home BP monitoring (Omron BP785N (HEM-7321-Z), Omron Healthcare) with an AF detector was used to measure the BP in patients. During each BP measurements, the electrocardiogram (ECG) was recorded simultaneously. Simultaneous BP measurements and ECG recordings were obtained from 99 subjects.

RESULTS

Twenty out of 20 patients with atrial fibrillation were correctly recognized by the device and the device correctly identified 67 patients with sinus rhythm as "Not-AF". On the other hand, 12 patients with basic rhythm: sinus rhythm were incorrectly referred to as "atrial fibrillation". In summary, the device has a diagnostic accuracy of 87.88% with a sensitivity of 100% and a specificity of 84.8%. On the other hand, in 23 patients, the raw data of the device showed that a body movement occurred during the measurement of the blood pressure. If these subjects were excluded of the analysis, then the diagnostic accuracy of the device would be even better, namely 90.79%. The sensitivity would be 100% and the specificity 89.5%.

CONCLUSION

These data suggest that an automated device for home blood pressure has an excellent diagnostic accuracy for detecting an AF and could be used as a reliable screening test for early diagnosis of atrial fibrillation. Body movements have an impact of the accuracy and specificity of a blood pressure monitor.

Estimated salt intake and risk of atrial fibrillation in a prospective community-based cohort

INTRODUCTION

Hypertension predisposes to atrial fibrillation (AF) - a major risk factor for ischaemic stroke. Since a high dietary salt consumption is associated with hypertension, we investigated the association between urinary sodium excretion as a marker for dietary sodium intake and risk of new-onset AF in community-dwelling adults.

METHOD

The UK Biobank includes 40- to 69-year-old British residents recruited 2006-2010. Participants were divided into sex-specific quintiles according to 24-hour sodium excretion estimated based on spot samples with the Kawasaki equation. We excluded participants with AF at baseline. Cox regression adjusted for cardiovascular risk factors was used to assess associations with risk of AF, using the third quintile as reference.

RESULTS

A total of 257 545 women and 215 535 men were included. During up to 10 years' follow-up, 2221 women and 3751 men were diagnosed with AF. There was a tendency for an increased risk of AF in the lowest and highest quintiles of estimated daily salt intake in both women and men. In the fully adjusted model, significant associations were seen amongst men in the lowest and highest quintiles of sodium excretion (hazard ratio, HR_Qv1 , 1.20; 95% CI, 1.08-1.32, P < 0.001, and HR_Qv5 1.15, 95% CI, 1.03-1.27, P = 0.011).

CONCLUSION

We found evidence for a U-shaped association between estimated daily salt intake and AF risk amongst men. A suggestive J-shaped association in women was not statistically confirmed, but analyses were likely underpowered. Our results suggest that above a certain physiological minimum level progressively higher salt intake is associated with increasing risk of AF.

Biophysics-based statistical learning: Application to heart and brain interactions

Initiatives such as the UK Biobank provide joint cardiac and brain imaging information for thousands of individuals, representing a unique opportunity to study the relationship between heart and brain. Most of research on large multimodal databases has been focusing on studying the associations among the available measurements by means of univariate and multivariate association models. However, these approaches do not provide insights about the underlying mechanisms and are often hampered by the lack of prior knowledge on the physiological relationships between measurements. For instance, important indices of the cardiovascular function, such as cardiac contractility, cannot be measured in-vivo. While these non-observable parameters can be estimated by means of biophysical models, their personalisation is generally an ill-posed problem, often lacking critical data and only applied to small datasets. Therefore, to jointly study brain and heart, we propose an approach in which the parameter personalisation of a lumped cardiovascular model is constrained by the statistical relationships observed between model parameters and brain-volumetric indices extracted from imaging, i.e. ventricles or white matter hyperintensities volumes, and clinical information such as age or body surface area. We explored the plausibility of the learnt relationships by inferring the model parameters conditioned on the absence of part of the target clinical features, applying this framework in a cohort of more than 3 000 subjects and in a pathological subgroup of 59 subjects diagnosed with atrial fibrillation. Our results demonstrate the impact of such external features in the cardiovascular model personalisation by learning more informative parameter-space constraints. Moreover, physiologically plausible mechanisms are captured through these personalised models as well as significant differences associated to specific clinical conditions.

Hypertension and Atrial Fibrillation: A Study on Epidemiology and Mendelian Randomization Causality

Introduction: Hypertension (HT) and atrial fibrillation (AF) often coexist. However, the causality between these two conditions remains to be determined.

Methods: We used individual participant data from the Atherosclerosis Risk in Communities (ARIC) prospective cohort with 9,474 participants. HT was ascertained at visit 1 (1987–1989), and incident AF was identified by ECGs conducted during study examinations at each visit, hospital discharge codes, and death certificates. We used the Kaplan–Meier estimate to compute the cumulative incidence of AF by the HT subgroup. Then we used Cox hazard regression model to assess the association between HT and incident AF. The causality between genetically determined HT and AF was analyzed by the two-sample Mendelian randomization (MR) based on publicly summarized genome-wide association studies (GWASs) data.

Results: A total of 1,414 cases (14.9%) of AF were identified during the follow-up period (median 24.1 years). After adjusting for all covariates, the hazard ratio between the participants with HT and incident AF was 1.50 [95% confidence interval (CI) 1.29–1.73]. In the HT → AF MR analysis, we detected a causal correlation between HT and AF (OR: 1.90, 95% CI 1.18–3.04, P = 0.01) with no evidence of heterogeneity from single-nucleotide polymorphisms. Besides, the genetically determined SBP and DBP (10 mmHg) were consistently associated with a higher risk of AF.

Conclusions: In the ARIC study, the incident AF increased by 50% in patients with HT. In the MR analysis, our results supported causal inference between HT and AF.

Ambulatory blood pressure and risk of new-onset atrial fibrillation in treated hypertensive patients

The aim of this study was to evaluate the influence of clinic and ambulatory blood pressure (BP) on the occurrence of new-onset atrial fibrillation (AF) in treated hypertensive patients. We studied 2135 sequential treated hypertensive patients aged >40 years. During the follow-up (mean 9.7 years, range 0.4-20 years), 116 events (new-onset AF) occurred. In univariate analysis, clinic, daytime, nighttime, and 24-h systolic BP were all significantly associated with increased risk of new-onset AF, that is, hazard ratio (95% confidence interval) per 10 mm Hg increment 1.22 (1.11-1.35), 1.36 (1.21-1.53), 1.42 (1.29-1.57), and 1.42 (1.26-1.60), respectively. After adjustment for various covariates in multivariate analysis, clinic systolic BP was no longer associated with increased risk of new-onset AF, whereas daytime, nighttime, and 24-h systolic BP remained significantly associated with outcome, that is, hazard ratio (95% confidence interval) per 10 mm Hg increment 1.09 (0.97-1.23), 1.23 (1.10-1.39), 1.16 (1.03-1.31), and 1.22 (1.06-1.40), respectively. Daytime, nighttime, and 24-h systolic BP are superior to clinic systolic BP in predicting new-onset AF in treated hypertensive patients. Future studies are needed to evaluate whether a better control of ambulatory BP might be helpful in reducing the occurrence of new-onset AF.

A greater burden of atrial fibrillation is associated with worse endothelial dysfunction in hypertension

Atrial fibrillation (AF) and hypertension often co-exist and both are associated with endothelial dysfunction. We hypothesised that AF would further worsen endothelium-dependent flow-mediated dilatation (FMD) in hypertension patients compared to those without AF. In a cross-sectional comparison, we measured brachial artery diameter at rest and during reactive hyperaemia following 5 min of arterial occlusion in two patient groups: AF (and hypertension) (n = 61) and hypertension control groups (n = 33). The AF (and hypertension) subgroups: permanent AF (n = 30) and paroxysmal AF (n = 31) were also assessed. The permanent AF patients received heart rate and blood pressure (BP) control optimisation and were then followed up after eight weeks for repeat FMD testing. There was no significant difference in FMD between AF (and hypertension) group and hypertension control group (4.6%, 95% CI [2.6-5.9%] vs 2.6%, 95% CI [1.9-5.3%]; p = 0.25). There was a significant difference in FMD between permanent AF and paroxysmal AF groups (3.1%, 95% CI [2.3-4.8%] vs 5.9%, 95% CI [4.0-8.1%]; p = 0.02). Endothelium-dependent FMD response showed a non-significant improvement trend following eight weeks of heart rate and BP optimisation (3.1%, 95% CI [2.3-4.8%] (baseline) vs 5.2%, 95% CI [3.9-6.5%] (follow up), p = 0.09). Presence of AF generally does not incrementally worsen endothelial dysfunction in hypertension patients, although the duration and frequency of AF (paroxysmal AF to permanent AF) does lead to worsening endothelial function. Eight weeks of BP optimisation did not significantly improve endothelial dysfunction as measured by FMD.

Epicardial Fat Volume as a New Imaging-Based Feature Associated with Risk of Recurrence after Pulmonary Veins Ablation in Atrial Fibrillation

Background: Atrial fibrillation (AF), a common arrhythmia in clinical practice, is associated with a high rate of complications and an increased risk for thromboembolic events. Pulmonary vein ablation is a new therapeutic option to cure AF; however, it remains associated with a high rate of recurrence. In this study we aimed to identify the clinical characteristics and imaging-based features that may predict the risk of recurrence after pulmonary veins ablation in atrial fibrillation.

Materials and method: Twenty-four patients with paroxysmal and persistent AF, who underwent radiofrequency catheter ablation and a 12-month follow-up were included in the study. Group 1 included 8 patients with AF recurrence, and group 2 included 16 patients with no AF recurrence. In all cases, cardiovascular risk factors, ejection fraction, left atrial diameter, atrial volumes, and epicardial fat volume were analyzed.

Results: CT analysis revealed that patients with AF recurrence presented a significantly larger mean index of left atrial volume (59.57 ± 8.52 mL/m2 vs. 49.99 ± 10.88 mL/m2, p = 0.04), right atrial volume (58.94 ± 8.37 mL/m2 vs. 43.21 ± 6.4 mL/m2, p<0.0001), and indexed bi-atrial volume (118.5 ± 15.82 mL/m2 vs. 93.19 ± 16.42 mL/m2, p = 0.005). At the same time, CT analysis of the epicardial adipose tissue volume indicated that patients with AF recurrence have a larger amount of epicardial fat than those without AF recurrence (176.4 ± 100.8 mL vs. 109.8 ± 40.73 mL, p = 0.02).

Conclusion: Left atrial diameter, indexed atrial volumes, and epicardial fat volume may be used as factors to identify patients at risk for developing recurrence after pulmonary vein ablation.

Atrial remodeling and atrial fibrillation in acquired forms of cardiovascular disease

Atrial fibrillation (AF) is prevalent in common conditions and acquired forms of heart disease, including diabetes mellitus (DM), hypertension, cardiac hypertrophy, and heart failure. AF is also prevalent in aging. Although acquired heart disease is common in aging individuals, age is also an independent risk factor for AF. Importantly, not all individuals age at the same rate. Rather, individuals of the same chronological age can vary in health status from fit to frail. Frailty can be quantified using a frailty index, which can be used to assess heterogeneity in individuals of the same chronological age. AF is thought to occur in association with electrical remodeling due to changes in ion channel expression or function as well as structural remodeling due to fibrosis, myocyte hypertrophy, or adiposity. These forms of remodeling can lead to triggered activity and electrical re-entry, which are fundamental mechanisms of AF initiation and maintenance. Nevertheless, the underlying determinants of electrical and structural remodeling are distinct in different conditions and disease states. In this focused review, we consider the factors leading to atrial electrical and structural remodeling in human patients and animal models of acquired cardiovascular disease or associated risk factors. Our goal is to identify similarities and differences in the cellular and molecular bases for atrial electrical and structural remodeling in conditions including DM, hypertension, hypertrophy, heart failure, aging, and frailty.

Hypertension and Arrhythmias

Hypertension is the most common cardiovascular risk factor and underlies heart failure, coronary artery disease, stroke, and chronic kidney disease. Hypertensive heart disease can manifest as cardiac arrhythmias. Supraventricular and ventricular arrhythmias may occur in the hypertensive patients. Atrial fibrillation and hypertension contribute to an increased risk of stroke. Some antihypertensive drugs predispose to electrolyte abnormalities, which may result in atrial and ventricular arrhythmias. A multipronged strategy involving appropriate screening, aggressive lifestyle modifications, and optimal pharmacotherapy can result in improved blood pressure control and prevent the onset or delay progression of heart failure, coronary artery disease, and cardiac arrhythmias.

Impact of pre-existing hypertension and control status before atrial fibrillation onset on cardiovascular prognosis in patients with non-valvular atrial fibrillation: A real-world database analysis in Japan

Hypertension is an important risk factor for non-valvular atrial fibrillation (NVAF) and its prognosis. However, there is no study to clarify the impact of pre-existing hypertension and BP control status before the onset of AF on the prognosis after the onset of AF. This retrospective real-world cohort analysis used data from the Japan Medical Data Center Co., Ltd database. The presence of NVAF and hypertension, plus the occurrence of adverse events, was based on ICD-10 codes in the database. The primary composite AF-related cardiovascular event end point included ischemic stroke, hemorrhagic stroke, and acute myocardial infarction. Of the 21 523 patients identified as having new-onset NVAF between January 2005 and June 2016, 7885 had blood pressure (BP) data before the onset of NVAF available and were included in the analysis (4001 with pre-existing hypertension and 3884 without pre-existing hypertension). The rate of primary composite end point events was 10.3 and 4.4 per 1000 patient-years in patients with and without hypertension, respectively (P < .001). In addition, lower systolic BP (<120 mm Hg) before the onset of NVAF was associated with a lower incidence of cardiovascular events after the development of NVAF (P < .001). This highlights the importance of earlier and tighter 24-hour BP control before the onset of NVAF in patients with hypertension, not only for reducing the occurrence of new-onset of NVAF, but also for reducing both hemorrhagic and ischemic cardiovascular events after the onset of NVAF.

Association and impact of hypertension defined using the 2017 AHA/ACC guidelines on the risk of atrial fibrillation in The Atherosclerosis Risk in Communities study

Background

Hypertension is an established risk factor for the development of atrial fibrillation (AF). We evaluated the association and population impact of hypertension, defined using the new 2017 guidelines, on risk of AF.

Methods

In this analysis, we included 14,915 participants in the Atherosclerosis Risk in Communities study without history of AF. Participants underwent blood pressure measurements at baseline and their antihypertensive medication use was assessed. Incident AF was ascertained from study electrocardiograms, hospital records and death certificates. Cox proportional models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) of AF among individuals with hypertension based on the JNC7 and 2017 ACC/AHA guidelines. Poisson models were used to obtain risk ratios and calculate population-attributable fractions (PAFs).

Results

We identified 2891 cases of incident AF during 21.4 years of mean follow-up. Prevalence of hypertension was 34 and 48% under the JNC7 and 2017 ACC/AHA definitions, respectively. HRs (95%CI) of AF in hypertensives versus non-hypertensives were 1.44 (1.32, 1.56) and 1.37 (1.26, 1.48) after multivariable adjustment under the old and new guidelines, respectively. The corresponding PAF (95%CI) using the old and new guidelines were 11% (8, 13%) and 13% (9, 16%), respectively.

Conclusions

Overall, our analysis shows that even though the prevalence of hypertension using the new criteria is 40% higher than with the old criteria, this does not translate into meaningful increases in AF attributable to hypertension. These results suggest that prevention or treatment of hypertension based on the new (versus old) guidelines may have limited impact on AF incidence.

Blood pressure-related electrocardiographic findings in healthy young individuals

Purpose: Elevated blood pressure induces electrocardiographic changes and is associated with an increase in cardiovascular disease later in life compared to normal blood pressure levels. The purpose of this study was to evaluate the association between normal to high normal blood pressure values (90-139/50-89 mmHg) and electrocardiographic parameters related to cardiac changes in hypertension in healthy young adults.Methods: Data from 1449 volunteers aged 18-30 years collected at our centre were analyzed. Only subjects considered healthy by a physician after review of collected data with systolic blood pressure values between 90 and 139 mmHg and diastolic blood pressure values between 50 and 89 mmHg were included. Subjects were divided into groups with 10 mmHg systolic blood pressure increment between groups for analysis of electrocardiographic differences. Backward multivariate regression analysis with systolic and diastolic blood pressure as a continuous variable was performed.Results: The mean age was 22.7 ± 3.0 years, 73.7% were male. P-wave area, ventricular activation time, QRS-duration, Sokolow-Lyon voltages, Cornell Product, J-point-T-peak duration corrected for heart rate and maximum T-wave duration were significantly different between systolic blood pressure groups. In the multivariate model with gender, body mass index and cholesterol, ventricular rate (standardized coefficient (SC): +0.182, p < .001), ventricular activation time in lead V6 (SC= +0.065, p = .048), Sokolow-Lyon voltage (SC= +0.135, p < .001), and Cornell product (SC= +0.137, p < .001) were independently associated with systolic blood pressure, while ventricular rate (SC= +0.179, p < .001), P-wave area in lead V1 (SC= +0.079, p = .020), and Cornell product (SC= +0.091, p = .006) were independently associated with diastolic blood pressure.Conclusion: Blood pressure-related electrocardiographic changes were observed incrementally in a healthy young population with blood pressure in the normal range. These changes were an increased ventricular rate, increased atrial surface area, ventricular activation time and increased ventricular hypertrophy indices on a standard 12 lead electrocardiogram.

Hypertension and Atrial Fibrillation: Doubts and Certainties From Basic and Clinical Studies

Hypertension and atrial fibrillation (AF) are 2 important public health priorities. Their prevalence is increasing worldwide, and the 2 conditions often coexist in the same patient. Hypertension and AF are strikingly related to an excess risk of cardiovascular disease and death. Hypertension ultimately increases the risk of AF, and because of its high prevalence in the population, it accounts for more cases of AF than other risk factors. Among patients with established AF, hypertension is present in about 60% to 80% of individuals. Despite the well-known association between hypertension and AF, several pathogenetic mechanisms underlying the higher risk of AF in hypertensive patients are still incompletely known. From an epidemiological standpoint, it is unclear whether the increasing risk of AF with blood pressure (BP) is linear or threshold. It is uncertain whether an intensive control of BP or the use of specific antihypertensive drugs, such as those inhibiting the renin-angiotensin-aldosterone system, reduces the risk of subsequent AF in hypertensive patients in sinus rhythm. Finally, in spite of the observational evidence suggesting a progressive relation between BP levels and the risk of thromboembolism and bleeding in patients with hypertension and AF, the extent to which BP should be lowered in these patients, including those who undergo catheter ablation, remains uncertain. This article summarizes the main basic mechanisms through which hypertension is believed to promote AF. It also explores epidemiological data supporting an evolutionary pathway from hypertension to AF, including the emerging evidence favoring an intensive BP control or the use of drugs, which inhibit the renin-angiotensin-aldosterone system to reduce the risk of AF. Finally, it examines the impact of non-vitamin K antagonist oral anticoagulants compared with warfarin in relation to hypertension.

Prevalence and risk factors for atrial fibrillation and its anticoagulant requirement in adults aged ≥40 in Jimma Town, Southwest Ethiopia: A community based cross-sectional study

BACKGROUND

There is no information on the prevalence and incidence of atrial fibrillation in Ethiopia. We aimed to investigate the prevalence, risk factors and anticoagulant requirements of atrial fibrillation in an elderly Jimma population.

METHODS

In a community-based cross-sectional study in 634 adult (≥40 years) Jimma population, we performed cardiovascular health examinations including a 12-lead electrocardiogram to estimate AF prevalence. A standardized questionnaire was used to collect information on medical history, lifestyle and use of medications. Stroke risk stratification was done using CHA2DS2-VASc score. We used logistic regressions to determine the potential risk factors of AF.

RESULTS

The overall prevalence of AF was 4.3%. AF was associated with sex, current smoking, hypertension and BMI. Nineteen out of twenty seven participants with AF were in need of anticoagulation to prevent risk of stroke.

CONCLUSION

The prevalence of AF is high and common risk factors were sex, current smoking, hypertension, and higher BMI in this cohort. More than two-third of study participants with AF were at higher need of oral anticoagulants.

The imminent epidemic of atrial fibrillation and its concomitant diseases - Myocardial infarction and heart failure - A cause for concern

Atrial fibrillation (AF) is increasingly common in the general population. It often coincides with myocardial infarction (MI) and heart failure (HF) which are also diseases in older adults. All three conditions share common cardiovascular risk factors. While hypertension and obesity are central risk factors for all three diseases, smoking and diabetes appear to have less impact on AF. To date, age is the single most important risk factor for AF in the general population. Further, epidemiological studies suggest a strong association of AF to MI and HF. The underlying pathophysiological mechanisms are complex and not fully understood. Both MI and HF can trigger development of AF, mainly by promoting structural and electrical atrial remodeling. On the other hand, AF facilitates HF and MI development via multiple mechanisms, resulting in a vicious circle of cardiac impairment and adverse cardiovascular prognosis. Consequently, to prevent and treat the coincidence of AF and HF or MI a strict optimization of cardiovascular risk factors is required.

American Heart Association High Blood Pressure Protocol 2017: A Literature Review

Hypertension is the most prevalent clinical symptom arising from various cardiovascular disorders. Likewise, it is considered a precursor or sequelae to the development of acute coronary artery disease and congestive heath failure (CHF). Hypertension has been considered a cardinal criterion to determine cardiovascular function. According to the World Health Organization (WHO) global observatory data, hypertension causes more than 7.5 million deaths a year, about 12.8% of the total human mortality. Similarly, the Center for Disease Control (CDC) states that 35% of the American adults have been estimated to have a persistently high blood pressure, which makes it about one in every three adults. Hypertension is a modifiable symptom that can be managed through pharmacological and non-pharmacological methods and standard protocols set forth by the American Heart Association (AHA). With new findings from various clinical trials related to the management of hypertension, new developments and recommendations have been made to update the previously established protocols for hypertension. This article aims to discuss and dissect the modern updates of hypertension management as comprehensively elaborated in the 2017 Hypertension Clinical Practice Guidelines.

Age as a Critical Determinant of Atrial Fibrillation: A Two-sided Relationship

The incidence of atrial fibrillation (AF), the most common sustained arrhythmia and a major public health burden, increases exponentially with age. However, mechanisms underlying this long-recognized association remain incompletely understood. Experimental and human studies have demonstrated the involvement of aging in several arrhythmogenic processes, including atrial electrical and structural remodelling, disturbed calcium homeostasis, and enhanced atrial ectopic activity/increased vulnerability to re-entry induction. Given this wide range of putative mechanisms, the task of delineating the specific effects of aging responsible for AF promotion is not simple, as aging is itself associated with increasing prevalence of a host of AF-predisposing conditions, including heart failure, coronary artery disease, and hypertension. Although we usually think of old age promoting AF, there is also evidence that young age may actually have a protective effect against AF occurrence. For example, the low AF incidence among populations of young patients with significant structural congenital heart disease and substantial atrial enlargement/remodelling suggests that younger age might protect against fibrillation in the diseased atrium; efforts at understating how younger age may prevent AF might be helpful in elucidating missing mechanistic links between AF and age. The goal of this paper is to review the epidemiologic and pathophysiologic evidence regarding mechanisms underlying age-related AF. Although the therapeutic options for AF have recently improved, major gaps still remain and a better understanding of the special relationship between age and AF may be important for the identification of new targets for therapeutic innovation.

Left atrial fibrosis quantification by late gadolinium-enhanced magnetic resonance: a new method to standardize the thresholds for reproducibility

Aims

Identification of left atrial (LA) fibrosis through late gadolinium-enhanced cardiac magnetic resonance (LGE-CMR) remains controversial due to the heterogeneity and lack of reproducibility of proposed methods. Our aim is to describe a normalized, reproducible, standardized method to evaluate LA fibrosis through LGE-CMR.

Methods and results

Electrocardiogram- and respiratory-gated 3-Tesla LGE-CMR was performed in 10 healthy young volunteers and 30 patients with atrial fibrillation (AF): 10 with paroxysmal AF, 10 with persistent AF, and 10 with a previous AF ablation procedure. Local image intensity ratio (IIR) of the LA was calculated as the absolute pixel intensity to mean blood pool intensity ratio. The healthy atrial tissue threshold was defined in young healthy volunteers (upper limit of normality set at IIR tissue mean plus 2 SDs). Dense atrial scarring was characterized in patients with previous radiofrequency-induced scarring (post-AF ablation patients). Validation groups consisted of patients with paroxysmal and persistent AFs. The upper limit of normal IIR was 1.20; IIR values higher than 1.32 (60% of mean maximum pixel intensity in post-ablation patients) were considered dense scar. Image intensity ratio values between 1.2 and 1.32 identified interstitial fibrosis. Patients with paroxysmal and persistent AFs had less atrial fibrotic tissue compared with post-ablation patients. Endocardial bipolar voltage was correlated to IIR values.

Conclusions

An IIR of 1.2 identifies the upper limit of normality in healthy young individuals. An IIR of >1.32 defines dense atrial fibrosis in post-ablation patients. Our results provide a consistent, comparable, and normalized tool to assess atrial arrhythmogenic substrate.

Addressing Multimorbidity and Polypharmacy in Individuals With Atrial Fibrillation

PURPOSE OF REVIEW

The objectives of this review were to (1) discuss how multimorbidity and polypharmacy contributes to the complexity of management among individuals with AF and (2) identify any interventions to manage polypharmacy in relation to AF.

RECENT FINDINGS

Based on the four landmark clinical trials of novel anticoagulants, the most common comorbidities with AF are hypertension, heart failure, diabetes, stroke and myocardial infarction. Polypharmacy was also found prevalent in 76.5% of patients with AF, with a median of six drugs per patient. Despite the consequences of polypharmacy in AF, there is very little evidence-based intervention designed to manage it. Hence, there is a need for further research to examine interventions to manage polypharmacy in relation to AF. Atrial fibrillation (AF) is the most common type of cardiac arrhythmia requiring treatment in adults. Due to the structural and/or electrophysiological abnormalities that occur in AF, patients are managed through the use of prophylactic anticoagulant and rate and/or rhythm control medications. However, these medications are considered high risk and can increase the chances of medication misadventure. Additionally, AF rarely occurs in isolation and is known to coexist with multiple other medical comorbidities, i.e. multimorbidity. This also increases the number of medications, i.e. polypharmacy and pill burden which results in treatment non-compliance to prescribed therapy.

The State of the Art: Atrial Fibrillation Epidemiology, Prevention, and Treatment

As the most common sustained arrhythmia in adults, atrial fibrillation (AF) is an established and growing epidemic. To provide optimal patient care, it is important for clinicians to be aware of AF's epidemiological trends, methods of risk reduction, and the various available treatment modalities. Our understanding of AF's pathophysiology has advanced, and with this new understanding has come advancements in prevention strategies as well as pharmacological and nonpharmacological treatment options. Following PubMed and MEDLINE searches for AF risk factors, epidemiology, and therapies, we reviewed relevant articles (and bibliographies of those articles) published from 2000 to 2016. This "state-of-the-art" review provides a comprehensive update on the understanding of AF in the world today, contemporary therapeutic options, and directions of ongoing and future study.

Atrial Fibrillation: The Science behind Its Defiance

Atrial fibrillation (AF) is the most prevalent arrhythmia in the world, due both to its tenacious treatment resistance, and to the tremendous number of risk factors that set the stage for the atria to fibrillate. Cardiopulmonary, behavioral, and psychological risk factors generate electrical and structural alterations of the atria that promote reentry and wavebreak. These culminate in fibrillation once atrial ectopic beats set the arrhythmia process in motion. There is growing evidence that chronic stress can physically alter the emotion centers of the limbic system, changing their input to the hypothalamic-limbic-autonomic network that regulates autonomic outflow. This leads to imbalance of the parasympathetic and sympathetic nervous systems, most often in favor of sympathetic overactivation. Autonomic imbalance acts as a driving force behind the atrial ectopy and reentry that promote AF. Careful study of AF pathophysiology can illuminate the means that enable AF to elude both pharmacological control and surgical cure, by revealing ways in which antiarrhythmic drugs and surgical and ablation procedures may paradoxically promote fibrillation. Understanding AF pathophysiology can also help clarify the mechanisms by which emerging modalities aiming to correct autonomic imbalance, such as renal sympathetic denervation, may offer potential to better control this arrhythmia. Finally, growing evidence supports lifestyle modification approaches as adjuncts to improve AF control.

Bone Morphogenetic Protein-7 Antagonizes Myocardial Fibrosis Induced by Atrial Fibrillation by Restraining Transforming Growth Factor-β (TGF-β)/Smads Signaling

Background

This aim of this study was to investigate the expression of BMP-7 in atrial fibrillation and illuminate the role of BMP-7 and TGF-β/Smads signaling in myocardial fibrosis.

Material/Methods

Fibrosis of myocardial fibroblasts was induced by TGF-β1 and the optimal condition was determined by the MTT assay. Cells with TGF-β1 treatment were sub-divided into 4 groups: TGF-β1 group, TGF-β1 + Smad3 siRNA group, TGF-β1 + BMP-7 group, and TGF-β1 + BMP-7 + Smad1/5 siRNA group. Cells were then analyzed by detecting the expression of epithelial cadherin (E-cadherin), collagen I, alpha smooth muscle cell actin (α-SMA), and activated Smads using Western blot. Mice were injected daily with Ach-CaCl₂ with or without the addition of BMP-7 and Smad1/5 siRNA over a period of 4 weeks. Cardiac functions were tested by echocardiogram assay and fibrosis was diagnosed by histopathological examination. Finally, molecule biomarkers were detected using standard procedures.

Results

TGF-β1 treatment significantly down-regulated E-cadherin expression and up-regulated expressions of Collagen I, α-SMA, and pSmad3 (P<0.05). The effects of TGF-β1 treatment can be significantly suppressed by Smad3 siRNA (P<0.05). Cells in the BMP-7 group exhibited significantly higher expression levels of E-cadherin and pSmad1/5 together with lower expression levels of pSmad3, collagen I, and α-SMA (P<0.05). Moreover, Smad1/5 siRNA can substantially repress the effects of BMP-7 (P<0.05) and results from the mice model coincided with those in myocardial fibroblasts.

Conclusions

BMP-7 can regulate TGF-β1/Smad3 by targeting Smad1/5 to antagonize fibrosis in myocardial fibroblasts resulting from atrial fibrillation.

Is there an association between the prevalence of atrial fibrillation and severity and control of hypertension? The REasons for Geographic And Racial Differences in Stroke study

The association of atrial fibrillation (AF) with the severity and control of hypertension (HTN) remains unclear. We analyzed data from the national biracial cohort of REasons for Geographic And Racial Differences in Stroke study. The AF prevalence ratios were estimated and full multivariable adjustment included demographics, risk factors, medication adherence, HTN duration, and antihypertensive medication classes. Of the 30,018 study participants (8.6% with AF), 4386 had normotension (4.3% with AF), 5916 had prehypertension (4.3 with AF%), 12,294 had controlled HTN (11.2% with AF), 5587 had uncontrolled HTN (8.1% with AF), 547 had controlled apparent treatment-resistant hypertension (aTRH) (19.2% with AF), and 1288 had uncontrolled aTRH (15.5% with AF). Compared with normotension, the AF prevalence ratios for prehypertension, controlled HTN, uncontrolled HTN, controlled aTRH, and uncontrolled aTRH groups in fully adjusted model were 1.01 (95% confidence interval: 0.84, 1.21), 1.42 (1.18, 1.71), 1.37 (1.14, 1.65), 1.17 (0.86, 1.58), and 1.42 (1.10, 1.84), respectively (P < .001). The prevalence of AF was similar among persons with HTN regardless of blood pressure level and antihypertensive treatment resistance.

Prevalence of electrocardiographic abnormalities based on hypertension severity and blood pressure levels: the Reasons for Geographic and Racial Differences in Stroke study

We evaluated the prevalence of major and minor electrocardiographic (ECG) abnormalities based on blood pressure (BP) control and hypertension (HTN) treatment resistance. We analyzed data from the Reasons for Geographic and Racial Differences in Stroke study of 20,932 participants who were divided into presence of major (n = 3782), only minor (n = 8944), or no (n = 8206) ECG abnormalities. The cohort was stratified into normotension (n = 3373), pre-HTN (n = 4142), controlled HTN (n = 8619), uncontrolled HTN (n = 3544), controlled apparent treatment-resistant HTN (aTRH, n = 400), and uncontrolled aTRH (n = 854) groups, and the prevalence ratios (PRs) of major and minor ECG abnormalities were assessed separately for each BP group. The full multivariable adjustment included demographics, risk factors, and HTN duration. Compared with normotension, the PRs of major ECG abnormalities for pre-HTN, controlled HTN, uncontrolled HTN, controlled aTRH, and uncontrolled aTRH groups were 1.01 (0.90-1.14), 1.30 (1.16-1.45), 1.37 (1.23-1.54), 1.42 (1.22-1.64), and 1.44 (1.26-1.65), respectively (P < .001), whereas the PRs of minor ECG abnormalities among each of the above BP groups were similar. Detection of major ECG abnormalities among hypertensive persons with poor control and treatment resistance may help improve their cardiovascular risk stratification and early intervention.

Atrial fibrillation among the black population in a Ugandan tertiary hospital

Background

Atrial fibrillation (AF) is the most common type of sustained cardiac arrhythmia in adults, accounting for one-third of hospitalizations due to arrhythmia and related complications worldwide. Previously, rheumatic heart disease was documented as the commonest cause of AF in sub-Saharan Africa. However, due to the prevailing epidemiological transition in sub-Saharan Africa, the risk factors and ensuing complications of AF have changed and are on the increase.

Methods

This was a descriptive cross-sectional study involving 102 patients presenting with AF who were recruited from the cardiology unit of Mulago National Referral Hospital, Uganda, over 3 months. Sociodemographic, medical history, and clinical data were obtained.

Results

The mean age of study participants was 52±21.3 years with a female predominance (58 [56.9%]). The commonest coexisting medical conditions were hypertension in 42% and rheumatic heart disease in 32% of the patients. The commonest echocardiographic abnormality was chamber dilation, noted in 76.8% of all patients. Heart failure was the most frequent complication encountered (50%) followed by left ventricular diastolic dysfunction and acute thromboembolic stroke documented in 19.6% and 12.8% of the study participants, respectively. Of the enrolled patients, ten (9.8%) died within 3 days of admission.

Conclusion

AF tends to occur at a younger age in Ugandan patients. The commonest underlying medical conditions among these patients were hypertension and rheumatic heart disease. Hence, all patients with hypertension and rheumatic heart disease should be meticulously screened for AF.

Relaxin suppresses atrial fibrillation in aged rats by reversing fibrosis and upregulating Na+ channels

BACKGROUND

Atrial fibrillation (AF) contributes significantly to morbidity and mortality in elderly patients and has been correlated with enhanced age-dependent atrial fibrosis. Reversal of atrial fibrosis has been proposed as therapeutic strategy to suppress AF.

OBJECTIVE

To test the ability of relaxin to reverse age-dependent atrial fibrosis and suppress AF.

METHODS

Aged F-344 rats (24 months old) were treated with subcutaneous infusion of vehicle or relaxin (0.4 mg/kg/day) for 2 weeks. Rat hearts were excised, perfused on a Langendorff apparatus, and stained with voltage and Ca(2+) indicator dyes. Optical mapping and programmed electrical stimulation was used to test arrhythmia vulnerability and changes in electrophysiological characteristics. Changes in protein expression and Na(+) current density (INa) were measured by tissue immunofluorescence and whole-cell patch clamp technique.

RESULTS

In aged rats, sustained AF was readily induced with a premature pulse (n = 7/8) and relaxin treatment suppressed sustained AF by a premature impulse or burst pacing (n = 1/6) (P < .01). Relaxin significantly increased atrial action potential conduction velocity and decreased atrial fibrosis. Relaxin treatment increased Nav1.5 expression (n = 6; 36% ± 10%) and decreased total collagen and collagen I (n = 5-6; 55%-66% ± 15%) in aged atria (P < .05) and decreased collagen I and III and TGF-β1 mRNA (P < .05). Voltage-clamp experiments demonstrated that relaxin treatment (100 nM for 2 days) increased atrial INa by 46% ± 4% (n = 12-13/group, P < .02).

CONCLUSION

Relaxin suppresses AF through an increase in atrial conduction velocity by decreasing atrial fibrosis and increasing INa. These data provide compelling evidence that relaxin may serve as an effective therapy to manage AF in geriatric patients by reversing fibrosis and modulating cardiac ionic currents.

Frequency of Left Ventricular Hypertrophy in Non-Valvular Atrial Fibrillation

Left ventricular hypertrophy (LVH) is significantly related to adverse clinical outcomes in patients at high risk of cardiovascular events. In patients with atrial fibrillation (AF), data on LVH, that is, prevalence and determinants, are inconsistent mainly because of different definitions and heterogeneity of study populations. We determined echocardiographic-based LVH prevalence and clinical factors independently associated with its development in a prospective cohort of patients with non-valvular (NV) AF. From the "Atrial Fibrillation Registry for Ankle-brachial Index Prevalence Assessment: Collaborative Italian Study" (ARAPACIS) population, 1,184 patients with NVAF (mean age 72 ± 11 years; 56% men) with complete data to define LVH were selected. ARAPACIS is a multicenter, observational, prospective, longitudinal on-going study designed to estimate prevalence of peripheral artery disease in patients with NVAF. We found a high prevalence of LVH (52%) in patients with NVAF. Compared to those without LVH, patients with AF with LVH were older and had a higher prevalence of hypertension, diabetes, and previous myocardial infarction (MI). A higher prevalence of ankle-brachial index ≤0.90 was seen in patients with LVH (22 vs 17%, p = 0.0392). Patients with LVH were at significantly higher thromboembolic risk, with CHA2DS2-VASc ≥2 seen in 93% of LVH and in 73% of patients without LVH (p <0.05). Women with LVH had a higher prevalence of concentric hypertrophy than men (46% vs 29%, p = 0.0003). Logistic regression analysis demonstrated that female gender (odds ratio [OR] 2.80, p <0.0001), age (OR 1.03 per year, p <0.001), hypertension (OR 2.30, p <0.001), diabetes (OR 1.62, p = 0.004), and previous MI (OR 1.96, p = 0.001) were independently associated with LVH. In conclusion, patients with NVAF have a high prevalence of LVH, which is related to female gender, older age, hypertension, and previous MI. These patients are at high thromboembolic risk and deserve a holistic approach to cardiovascular prevention.