Prevention of atrial fibrillation: report from a national heart, lung, and blood institute workshop

Role of CHA2DS2-VASc score in predicting new-onset atrial fibrillation in patients with type 2 diabetes mellitus with and without hyperosmolar hyperglycaemic state: real-world data from a nationwide cohort

PURPOSE

The objective of the current study was to explore the role of CHA₂DS₂-VASc score in predicting incidence of atrial fibrillation (AF) in patients with type 2 diabetes mellitus (DM). Furthermore, the use of the CHA₂DS₂-VASc score for stratifying new-onset AF risk in patients with DM and with/without hyperosmolar hyperglycaemic state (HHS) was also compared.

METHODS

The study subjects were identified from Longitudinal Health Insurance Database provided by the National Health Research Institutes. The patients with DM were divided into two groups based on a history of HHS or not. The predictive ability of CHA₂DS₂-VASc score for stratifying new-onset AF risk in the two groups was calculated using the area under the curve of receiver-operating characteristic (AUROC).

RESULTS

The present study involved a total of 69 530 patients with type 2 DM. Among them, 1558 patients had a history of HHS, whereas 67 972 patients did not. The AUROC of the CHA₂DS₂-VASc score as a predictor of incident AF in patients with DM and with/without HHS was 0.67 (95% CI 0.59 to 0.75) and 0.71 (95% CI 0.70 to 0.72), respectively.

CONCLUSIONS

To conclude, we reported for the first time on the assessment of CHA₂DS₂-VASc score for incident AF risk discrimination in patients with type 2 DM. We further found that the predictive ability of the CHA₂DS₂-VASc score was attenuated in patients with type 2 DM and with HHS in comparison with those without HHS.

Genetic Predisposition, Clinical Risk Factor Burden, and Lifetime Risk of Atrial Fibrillation

BACKGROUND

The long-term probability of developing atrial fibrillation (AF) considering genetic predisposition and clinical risk factor burden is unknown.

METHODS

We estimated the lifetime risk of AF in individuals from the community-based Framingham Heart Study. Polygenic risk for AF was derived using a score of ≈1000 AF-associated single-nucleotide polymorphisms. Clinical risk factor burden was calculated for each individual using a validated risk score for incident AF comprised of height, weight, systolic and diastolic blood pressure, current smoking status, antihypertensive medication use, diabetes mellitus, history of myocardial infarction, and history of heart failure. We estimated the lifetime risk of AF within tertiles of polygenic and clinical risk.

RESULTS

Among 4606 participants without AF at 55 years of age, 580 developed incident AF (median follow-up, 9.4 years; 25th-75th percentile, 4.4-14.3 years). The lifetime risk of AF >55 years of age was 37.1% and was substantially influenced by both polygenic and clinical risk factor burden. Among individuals free of AF at 55 years of age, those in low-polygenic and clinical risk tertiles had a lifetime risk of AF of 22.3% (95% confidence interval, 15.4-9.1), whereas those in high-risk tertiles had a risk of 48.2% (95% confidence interval, 41.3-55.1). A lower clinical risk factor burden was associated with later AF onset after adjusting for genetic predisposition (P<0.001).

CONCLUSIONS

In our community-based cohort, the lifetime risk of AF was 37%. Estimation of polygenic AF risk is feasible and together with clinical risk factor burden explains a substantial gradient in long-term AF risk.

Improved Multiscale Entropy Technique with Nearest-Neighbor Moving-Average Kernel for Nonlinear and Nonstationary Short-Time Biomedical Signal Analysis

Analysis of biomedical signals can yield invaluable information for prognosis, diagnosis, therapy evaluation, risk assessment, and disease prevention which is often recorded as short time series data that challenges existing complexity classification algorithms such as Shannon entropy (SE) and other techniques. The purpose of this study was to improve previously developed multiscale entropy (MSE) technique by incorporating nearest-neighbor moving-average kernel, which can be used for analysis of nonlinear and non-stationary short time series physiological data. The approach was tested for robustness with respect to noise analysis using simulated sinusoidal and ECG waveforms. Feasibility of MSE to discriminate between normal sinus rhythm (NSR) and atrial fibrillation (AF) was tested on a single-lead ECG. In addition, the MSE algorithm was applied to identify pivot points of rotors that were induced in ex vivo isolated rabbit hearts. The improved MSE technique robustly estimated the complexity of the signal compared to that of SE with various noises, discriminated NSR and AF on single-lead ECG, and precisely identified the pivot points of ex vivo rotors by providing better contrast between the rotor core and the peripheral region. The improved MSE technique can provide efficient complexity analysis of variety of nonlinear and nonstationary short-time biomedical signals.

Factors influencing P terminal force in lead V1 of the ECG in hemodialysis patients

INTRODUCTION

Atrial fibrillation (AF) is a highly prevalent arrhythmia in hemodialysis (HD) patients, and an HD session may be a trigger for AF episodes. An abnormal P-terminal force in lead V1 (PTFV1) may predict new-onset AF in HD patients. The aim of the study was to assess the influence of the HD process on PTFV1 and to evaluate possible factors influencing PTFV1 in a group of selected HD patients.

MATERIAL AND METHODS

One hundred and fifty-three selected HD patients entered the study. Blood chemistry, electrocardiography, and impedance cardiography were evaluated before and after HD. Echocardiography was performed on the morning after dialysis. Abnormal PTFV1 was defined as PTFV1 > 40 mm × ms.

RESULTS

Abnormal PTFV1 was found in 35.3% of patients before dialysis and in 48.4% of patients after dialysis. The results of multiple regression analysis revealed that the independent predictors of pre-dialysis abnormal PTFV1 were: left atrial volume index (p = 0.002), left ventricular mass index (p = 0.014), and pre-dialysis thoracic fluid content (p = 0.021) values. The independent predictors of HD-induced abnormal PTFV1 values were larger differences between pre-dialysis and post-dialysis values of serum potassium (p < 0.001) and mean arterial pressure (p = 0.008).

CONCLUSIONS

Abnormal PTFV1 is prevalent in HD patients. The HD process adversely affects PTFV1 values. Pre-dialysis abnormal PTFV1 is mainly associated with structural heart abnormalities and hydration status. HD-induced abnormal PTFV1 is associated predominantly with serum potassium changes as well as HD-induced hypotension. Our results suggest possible risk factors for AF; however, their clinical significance needs to be confirmed in follow-up studies.

Low-dose green tea intake reduces incidence of atrial fibrillation in a Chinese population

The aim of the present study was to assessthe association between green tea intake and incidence of atrial fibrillation (AF) in a Chinese population. A total of 801 (mean age: 62 years; 56% male) subjects were enrolled: 401 AF patients and 400 controls. All subjects completed a questionnaire and the associations between their green tea drinking habits and incidence of AF were assessed using the odds ratio (OR) and binary logistic regression. After multivariate adjustment, green tea intake presented as a protective factor against the incidence of AF (OR: 0.349, 95% CI: 0.253-0.483, P < 0.001). The green tea protection showed downward trend with increasing green tea intake (P for the trend= 0.001). Low frequency, low concentration, short-term tea consumption was classified as low-dose green tea intake. Green tea intake decreased the incidence of both paroxysmal AF (OR: 0.307, 95% CI: 0.216-0.436, P < 0.001) and persistent AF (OR: 0.355, 95% CI: 0.261-0.482, P < 0.001) and may be associated with a decreased incidence of AF. This study suggests that low-dose green tea intake strongly protects against AF.

Toll-Like Receptors 2 and 4 Predict New-Onset Atrial Fibrillation in Acute Myocardial Infarction Patients

Myocardial infarction (MI) can cause new-onset atrial fibrillation (AF) due to cardiac remodeling. As a recent study has shown, inflammatory factors are closely tied to cell death and survival in myocardial ischemia injury. Toll-like receptors (TLRs) have been shown to participate in the process of myocardial infarction as innate immune factors.The subjects were divided into 3 groups: healthy controls (n = 82), MI patients (n = 84), and AFMI (new-onset atrial fibrillation after myocardial infarction) patients (n = 85). Peripheral blood mononuclear cell (PBMC) TLR mRNA expression was detected by rt-PCR. Western blot was used to analyze PBMC TLRs and their downstream signal protein expression. PBMCs were presented as TLR2 expression or TLR4 expression using flow cytometry.From mRNA to protein detection, PBMC TLR2 and TLR4 were significantly higher in the AFMI group than in the control group and MI group. A similar tendency was also observed in the expression of downstream signaling proteins. When further analyzed with TLR2 and TLR4 antibodies by flow cytometry, PBMC levels also appeared to be higher in AFMI patients than those in MI patients and the healthy control group.In our study, PBMC TLRs and their downstream signaling proteins were significantly higher in the acute myocardial infarction patients with new-onset atrial fibrillation compared with healthy people and acute myocardial infarction patients without new-onset atrial fibrillation. They have the potential to be novel biomarkers for new-onset atrial fibrillation after acute myocardial infarction.

Association between Sleep Apnea Hypopnea Syndrome and the Risk of Atrial Fibrillation: A Meta-Analysis of Cohort Study

Numerous reports have been done to seek the relationship between sleep apnea hypopnea syndrome (SAHS) and the risk of atrial fibrillation (AF). However, definite conclusion has not yet been fully established. We examined whether SAHS increases AF incidence in common population and summarized all existing studies in a meta-analysis. We summarized the current studies by searching related database for potential papers of the association between SAHS and the risk of AF. Studies that reported original data or relative risks (RRs) with 95% confidence intervals (CIs) for the associations were included. Sensitivity analyses were performed by omitting each study iteratively and publication bias was detected by Begg's tests. Eight eligible studies met the inclusion criteria. Fixed effects meta-analysis showed that SAHS increased AF risk in the common population (RR = 1.70, 95% CI: 1.53-1.89, P = 0.002, I2 = 69.2%). There was a significant association between mild SAHS and the risk of AF (RR = 1.52, 95% CI: 1.28-1.79, P = 0.01, I2 = 78.4%), moderate SAHS (RR = 1.88, 95% CI: 1.55-2.27, P = 0.017, I2 = 75.6%), and severe SAHS (RR = 2.16, 95% CI: 1.78-2.62, P < 0.001, I2 = 91.0%). The results suggest that sleep apnea hypopnea syndrome could increase the risk of AF, and the higher the severity of SAHS, the higher risk of atrial fibrillation.

Chocolate consumption and risk of atrial fibrillation: Two cohort studies and a meta-analysis

BACKGROUND

Chocolate consumption has been inconsistently associated with risk of atrial fibrillation (AF). We investigated the association between chocolate consumption and risk of AF in Swedish adults from two cohort studies and conducted a meta-analysis to summarize available evidence from cohort studies on this topic.

METHODS

Our study population comprised 40,009 men from the Cohort of Swedish Men and 32,486 women from the Swedish Mammography Cohort. Incident AF cases were ascertained through linkage with the Swedish National Patient Register. Published cohort studies of chocolate consumption in relation to risk of AF were identified by a PubMed search through September 14, 2017.

RESULTS

During a mean follow-up of 14.6 years, AF was diagnosed in 9978 Swedish men and women. Compared with non-consumers, the multivariable hazard ratio of AF for those in the highest category of chocolate consumption (≥3-4 servings/week) was 0.96 (95% CI 0.88-1.04). In a random-effects meta-analysis of 5 cohort studies, including 180,454 participants and 16,356 AF cases, the hazard ratios of AF were 0.97 (95% CI 0.94-1.01) per 2 servings/week increase in chocolate consumption and 0.96 (95% CI 0.90-1.03) for the highest versus lowest category of chocolate consumption.

CONCLUSION

Available data provide no evidence of an association of chocolate consumption with risk of AF.

Comprehensive risk reduction in patients with atrial fibrillation: Emerging diagnostic and therapeutic options

There are exciting new developments in several areas of atrial fibrillation (AF) management that carry the hope of improving outcomes in AF patients. This paper is an executive summary that summarises the proceedings from the 3rd AFNET/EHRA consensus conference on atrial fibrillation, held in Sophia Antipolis from November 7th to 9th 2010, shortly after the release of the new ESC guidelines on AF. The conference was jointly organised by the German Atrial Fibrillation competence NETwork (AFNET) and the European Heart Rhythm Association (EHRA). This executive summary report covers four sections: 1. Risk factors and risk markers for AF, 2. Pathophysiological classification of AF, 3. Relevance of monitored AF duration for AF-related outcomes, and 4. Perspectives and needs for implementing better antithrombotic therapy.

Study protocol for Smartphone Monitoring for Atrial fibrillation in Real-Time in India (SMART-India): a community-based screening and referral programme

INTRODUCTION

Atrial fibrillation (AF), the world's most common arrhythmia, often goes undetected and untreated in low-resource communities, including India, where AF epidemiology is undefined. AF is an important risk factor for stroke, which plagues an estimated 1.6 million Indians annually. As such, early detection of AF and management of high-risk patients is critically important to decrease stroke burden in individuals with AF. This study aims to describe the epidemiology of AF in Anand District, Gujarat, India, characterise the clinical profile of individuals who are diagnosed with AF and determine the performance of two mobile technologies for community-based AF screening.

METHODS

This observational study builds on findings from a previous feasibility study and leverages two novel technologies as well as an existing community health programme to perform door-to-door AF screening for 2000 people from 60 villages of Anand District, Gujarat, India using local health workers. A single-lead ECG and a pulse-based application is used to screen each individual for AF three times over a period of 5 days. Participants with suspected arrhythmias are followed up by study cardiologist who makes final diagnoses. Participants diagnosed with AF are initiated on treatment based on current anticoagulation guidelines and clinical reasoning.

ANALYTICAL PLAN

Age-stratified and sex-stratified prevalence of AF in the Anand District will be calculated for sample and estimated for Anand distribution using survey design weights. Sociodemographic and clinical factors associated with AF will be evaluated using multivariable regression methods. Performance of each mobile technology in detecting AF will be evaluated using a 12-lead ECG interpretation as the gold standard.

ETHICS AND DISSEMINATION

This protocol was approved separately by the Institutional Review Board of University of Massachusetts Medical School and the Human Research Ethics Committee at Charutar Arogya Mandal. The findings of this study will be disseminated through peer-reviewed journals and scientific conferences.

Emergency Department, Hospital Inpatient, and Mortality Burden of Atrial Fibrillation in the United States, 2006 to 2014

The prevalence of atrial fibrillation (AF) is increasing in the United States as the population ages, but national surveillance is lacking. This cross-sectional study (2006 to 2014) analyzed data from the Healthcare Cost and Utilization Project's Nationwide Emergency Department Sample, the National (Nationwide) Inpatient Sample, and the National Vital Statistics System. Event totals were estimated independently for emergency department (ED) visits, hospitalizations, and mortality, and then collectively after applying criteria to identify mutually exclusive events. Rates were calculated for AF as primary diagnosis or underlying cause of death (primary AF), as well as secondary diagnosis or contributing cause of death (co-morbid AF), and standardized by age to the 2010 US population. From 2006 to 2014, event rates increased for primary AF (249 to 268 per 100,000) and co-morbid AF (1,473 to 1,835 per 100,000). In 2014, an estimated 599,790 ED visits, 453,060 hospitalizations, and 21,712 deaths listed AF as primary. A total of 684,470 mutually exclusive primary AF and 4,695,997 mutually exclusive co-morbid AF events occurred. Among ED visits and hospitalizations with primary AF, the most common secondary diagnoses were hypertension, heart failure, ischemic heart disease, and diabetes. The mean cost per hospitalization with primary AF was $8,819. Mean costs were higher for those with co-morbid AF versus those without co-morbid AF among hospitalizations with a primary diagnosis of ischemic heart disease, heart failure, stroke, hypertension, or diabetes (all p ≤0.01). In conclusion, with the substantial health and economic impact of AF and an aging US population, improved diagnosis, prevention, management, and surveillance of AF are increasingly important.

Transient atrial fibrillation and risk of stroke after acute myocardial infarction

Atrial fibrillation (AF) is a frequent complication of acute myocardial infarction (AMI). In the AMI setting, AF is frequently brief and attributed to acute haemodynamic changes, inflammation or ischaemia. However, it remains uncertain whether transient AF episodes are associated with a subsequent increased risk of ischaemic stroke. We studied the impact of transient new-onset AF on the one-year risk of ischaemic stroke or transient ischaemic attack (TIA) in a retrospective cohort of 2,402 patients with AMI. Patients with previous AF or AF at hospital discharge were excluded. Transient AF occurred in 174 patients (7.2%) during the initial hospitalisation. During one year follow-up after hospital discharge, stroke or TIA occurred in 16 (9.2%) and 58 (2.6%) patients with and without transient AF, respectively (p< 0.0001). Compared with patients without transient AF, the adjusted hazard ratio for stroke or TIA in patients with transient AF was 3.03 (95% CI 1.73–5.32; p< 0.0001). Stroke or TIA occurred in 2.6% of patients without AF, 6.3% of patients with transient AF treated with oral anticoagulants, and 9.9% of patients with transient AF treated with antiplatelet agents. The incidence of recurrent AF after hospital discharge was markedly higher in patients with transient AF during the index hospitalisation (22.8% vs. 2.0%, p< 0.0001). In conclusion, transient AF complicating AMI is associated with an increased future risk of ischaemic stroke and TIA, particularly in patients treated with antiplatelet agents alone. High AF recurrence rates in these patients also suggest that oral anticoagulants should be strongly considered.

Statins and new-onset atrial fibrillation in a cohort of patients with hypertension. Analysis of electronic health records, 2006-2015

Hypertension is the most prevalent risk factor for new-onset atrial fibrillation (AF). But few studies have addressed the effect of statins on the incidence of this arrhythmia in patients with hypertension. This study aimed to evaluate the effect of statins on new-onset of this arrhythmia in a hypertensive population, accounting for AF risk. Data from the Information System for the Development of Research in Primary Care was used to recruit a retrospective cohort of ≥55-year-old hypertensive individuals with no ischemic vascular disease, in 2006-2007, followed up through 2015. The effect of initiating statin treatment on new-onset atrial fibrillation was assessed with Cox proportional hazards models adjusted by the propensity score of receiving statin treatment, in the overall study population and stratified by AF risk. Of 100 276 included participants, 9814 initiated statin treatment. The AF incidence per 1000 person-years (95% confidence interval) was 12.5 (12.3-12.8). Statin use associated with a significant (9%) reduction in AF incidence. Differences in absolute AF incidence were higher in the highest AF risk subgroup, and the estimated number needed to treat to avoid one case was 720. The relative effect was poor, similar across groups, and non-significant, as was the association of statins with adverse effects. We found a limited protective effect of statins over new-onset AF in this hypertensive population with no ischemic vascular disease. If there is no further indication, hypertensive patients would not benefit from statin use solely for AF primary prevention.

Atrial fibrillation and the risk of myocardial infarction: a nation-wide propensity-matched study

In addition to being an established complicating factor for myocardial infarction (MI), recent studies have revealed that atrial fibrillation (AF) increased risk of MI. This study is to evaluate the risk of MI associated with AF in a nationwide population based cohort. We examine the association between AF and incident MI in 497,366 adults from the Korean National Health Insurance Service database, who were free of AF and MI at baseline. AF group (n = 3,295) was compared with propensity matched no-AF group (n = 13,159). Over 4.2 years of follow up, 137 MI events occurred. AF was associated with 3-fold increased risk of MI (HR, 3.1; 95% CI, 2.22-4.37) in both men (HR, 2.91; 95% CI 1.91-4.45) and women (HR, 3.52; 95% CI 2.01-6.17). The risk of AF-associated MI was higher in patients free of hypertension, diabetes, ischemic stroke, and dyslipidemia at baseline. The cumulative incidence of AF-associated MI was lower in patients on anticoagulant and statin therapies. Our finding suggests that AF complications beyond stoke should extend to total mortality to include MI.

Recent advances in rhythm control for atrial fibrillation

Atrial fibrillation (AF) remains a difficult management problem. The restoration and maintenance of sinus rhythm-rhythm control therapy-can markedly improve symptoms and haemodynamics for patients who have paroxysmal or persistent AF, but some patients fare well with rate control alone. Sinus rhythm can be achieved with anti-arrhythmic drugs or electrical cardioversion, but the maintenance of sinus rhythm without recurrence is more challenging. Catheter ablation of the AF triggers is more effective than anti-arrhythmic drugs at maintaining sinus rhythm. Whilst pulmonary vein isolation is an effective strategy, other ablation targets are being evaluated to improve sinus rhythm maintenance, especially in patients with chronic forms of AF. Previously extensive ablation strategies have been used for patients with persistent AF, but a recent trial has shown that pulmonary vein isolation without additional ablation lesions is associated with outcomes similar to those of more extensive ablation. This has led to an increase in catheter-based technology to achieve durable pulmonary vein isolation. Furthermore, a combination of anti-arrhythmic drugs and catheter ablation seems useful to improve the effectiveness of rhythm control therapy. Two large ongoing trials evaluate whether a modern rhythm control therapy can improve prognosis in patients with AF.

Mediterranean diet and risk of heart failure: results from the PREDIMED randomized controlled trial

AIMS

The aim of this study was to evaluate the effect of the Mediterranean diet (MedDiet) on the incidence of heart failure (HF), a pre-specified secondary outcome in the PREDIMED (PREvención con DIeta MEDiterránea) primary nutrition-intervention prevention trial.

METHODS AND RESULTS

Participants at high risk of cardiovascular disease were randomly assigned to one of three diets: MedDiet supplemented with extra-virgin olive oil (EVOO), MedDiet supplemented with nuts, or a low-fat control diet. Incident HF was ascertained by a Committee for Adjudication of events blinded to group allocation. Among 7403 participants without prevalent HF followed for a median of 4.8 years, we observed 29 new HF cases in the MedDiet with EVOO group, 33 in the MedDiet with nuts group, and 32 in the control group. No significant association with HF incidence was found for the MedDiet with EVOO and MedDiet with nuts, compared with the control group [hazard ratio (HR) 0.68; 95% confidence interval (CI) 0.41-1.13, and HR 0.92; 95% CI 0.56-1.49, respectively].

CONCLUSION

In this sample of adults at high cardiovascular risk, the MedDiet did not result in lower HF incidence. However, this pre-specified secondary analysis may have been underpowered to provide valid conclusions. Further randomized controlled trials with HF as a primary outcome are needed to better assess the effect of the MedDiet on HF risk.

TRIAL REGISTRATION

ISRCTN35739639.

Leukocyte TRP channel gene expressions in patients with non-valvular atrial fibrillation

Atrial fibrillation (AF) is the most common arrhythmia in clinical practice and is a major cause of morbidity and mortality. The upregulation of TRP channels is believed to mediate the progression of electrical remodelling and the arrhythmogenesis of the diseased heart. However, there is limited data about the contribution of the TRP channels to development of AF. The aim of this study was to investigate leukocyte TRP channels gene expressions in non-valvular atrial fibrillation (NVAF) patients. The study included 47 NVAF patients and 47 sex and age matched controls. mRNA was extracted from blood samples, and real-time polymerase chain reaction was performed for gene expressions by using a dynamic array system. Low levels of TRP channel expressions in the controls were markedly potentiated in NVAF group. We observed marked increases in MCOLN1 (TRPML1), MCOLN2 (TRPML2), MCOLN3 (TRPML3), TRPA1, TRPM1, TRPM2, TRPM3, TRPM4, TRPM5, TRPM6, TRPM7, TRPM8, TRPC1, TRPC2, TRPC3, TRPC4, TRPC5, TRPC6, TRPC7, TRPV1, TRPV2, TRPV3, TRPV4, TRPV5, TRPV6, and PKD2 (TRPP2) gene expressions in NVAF patients (P < 0.05). However, there was no change in PKD1 (TRPP1) gene expression. This is the first study to provide evidence that elevated gene expressions of TRP channels are associated with the pathogenesis of NVAF.

Ectopy on a Single 12-Lead ECG, Incident Cardiac Myopathy, and Death in the Community

BACKGROUND

Atrial fibrillation and heart failure are 2 of the most common diseases, yet ready means to identify individuals at risk are lacking. The 12-lead ECG is one of the most accessible tests in medicine. Our objective was to determine whether a premature atrial contraction observed on a standard 12-lead ECG would predict atrial fibrillation and mortality and whether a premature ventricular contraction would predict heart failure and mortality.

METHODS AND RESULTS

We utilized the CHS (Cardiovascular Health) Study, which followed 5577 participants for a median of 12 years, as the primary cohort. The ARIC (Atherosclerosis Risk in Communities Study), the replication cohort, captured data from 15 792 participants over a median of 22 years. In the CHS, multivariable analyses revealed that a baseline 12-lead ECG premature atrial contraction predicted a 60% increased risk of atrial fibrillation (hazard ratio, 1.6; 95% CI, 1.3-2.0; P<0.001) and a premature ventricular contraction predicted a 30% increased risk of heart failure (hazard ratio, 1.3; 95% CI, 1.0-1.6; P=0.021). In the negative control analyses, neither predicted incident myocardial infarction. A premature atrial contraction was associated with a 30% increased risk of death (hazard ratio, 1.3; 95% CI, 1.1-1.5; P=0.008) and a premature ventricular contraction was associated with a 20% increased risk of death (hazard ratio, 1.2; 95% CI, 1.0-1.3; P=0.044). Similarly statistically significant results for each analysis were also observed in ARIC.

CONCLUSIONS

Based on a single standard ECG, a premature atrial contraction predicted incident atrial fibrillation and death and a premature ventricular contraction predicted incident heart failure and death, suggesting that this commonly used test may predict future disease.

Current state of the art for cardiac arrhythmia gene therapy

Cardiac arrhythmias are a leading cause of morbidity and mortality. Currently available therapeutic options lack sufficient efficacy and safety. Gene therapy has been proposed for treatment of cardiac arrhythmias. This review will discuss the current state of development for arrhythmia gene therapy. So far, all published studies are short-term, proof-of-concept animal studies. Potential replacement of cardiac pacemakers has been shown for combination gene therapy using the HCN2 gene and either the gene for adenylate cyclase, the skeletal muscle isoform of the sodium channel, or a dominant negative mutant of the potassium channel responsible for resting membrane potential. Atrial fibrillation has been prevented by gene transfer of either a dominant negative mutant of a repolarizing potassium channel, a gap junction, or an siRNA directed against caspase 3. Inherited arrhythmia syndromes have been corrected by replacement of the causative genes. Post-infarct ventricular tachycardia has been reduced by gene therapy with the skeletal muscle sodium channel and connexins and eliminated with the dominant negative mutant of the potassium channel responsible for resting membrane potential. These ideas show considerable promise. Long-term efficacy and safety studies are required to see if they can become viable therapies.

CHADS2 and modified CHA2DS2-VASc scores for the prediction of congestive heart failure in patients with nonvalvular atrial fibrillation

Background & purpose

We have conducted a retrospective observational study to analyze the correlation between the CHADS₂ score, the modified CHA₂DS₂-VASc (mCHA₂DS₂-VASc) score, and the incidence of all-cause death and congestive heart failure (CHF).

Methods

The study cohort consisted of 292 consecutive patients with nonvalvular atrial fibrillation (NVAF) admitted to our hospital from 2012 to 2014. Electronic medical records were used to confirm medical history including prior heart failure, hypertension, diabetes, stroke, and coronary disease. A follow-up survey for all-cause deaths and incidence of CHF was carried out from the baseline data to May 2015. We analyzed the correlation between each score and the endpoints using the Kaplan-Meier method and the Cox proportional hazards model.

Result

During the follow up period (mean=1.6 years), 69 all-cause deaths and 58 CHF events occurred in the cohort. There was no significant association between these scores and all-cause death in our CHF cohort. The incidence of CHF significantly increased along with increased CHADS₂ (p=0.018) or mCHA₂DS₂-VASc scores (p=0.044). The hazard ratio (HR) for CHF after adjustment for drug treatment was obtained from a Cox proportional hazards model. The HRs for the CHADS₂ and mCHA₂DS₂-VASc scores were 1.38 (95% CI; 1.13–1.68) and 1.35 (95% CI; 1.24–1.59), respectively.

Conclusion

Calculation of the CHADS₂ and mCHA₂DS₂-VASc scores in order to evaluate the risk of systemic thromboembolism was useful to predict the onset of CHF, but not all-cause death, in patients with NVAF.

Progression and reversibility of stretch induced atrial remodeling: Characterization and clinical implications

Atrial fibrillation (AF) is the most common sustained arrhythmia and across the developed nations, it contributes to increasing hospitalizations and healthcare burden. Several comorbidities and risk factors including hypertension, heart failure, obstructive sleep apnoea and obesity are known to play an important role in the initiation and perpetuation of AF and atrial stretch or dilatation may play a central mechanistic role. The impact of atrial stretch in the development of AF can vary dependent on the underlying disease. This review focuses on understanding the substrate for AF in conditions of acute and chronic stretch and in the presence of common co-morbidities or risk factors through the review of findings in both animal and human studies. Additionally, the reversibility of atrial remodeling following stretch release will also be discussed. Identification of clinical conditions associated with increased atrial stretch as well as the treatment or prevention of these conditions may help to prevent AF progression and improve sinus rhythm maintenance.

Atrial-ventricular differences in rabbit cardiac voltage-gated Na+ currents: Basis for atrial-selective block by ranolazine

Background

Class 1 antiarrhythmic drugs are highly effective in restoring and maintaining sinus rhythm in atrial fibrillation patients but carry a risk of ventricular tachyarrhythmia. The antianginal agent ranolazine is a prototypic atrial-selective voltage-gated Na⁺ channel blocker but the mechanisms underlying its atrial-selective action remain unclear.

Objective

The present study examined the mechanisms underlying the atrial-selective action of ranolazine.

Methods

Whole-cell voltage-gated Na⁺ currents (I_Na) were recorded at room temperature (∼22°C) from rabbit isolated left atrial and right ventricular myocytes.

Results

I_Na conductance density was ∼1.8-fold greater in atrial than in ventricular cells. Atrial I_Na was activated at command potentials ∼7 mV more negative and inactivated at conditioning potentials ∼11 mV more negative than ventricular I_Na. The onset of inactivation of I_Na was faster in atrial cells than in ventricular myocytes. Ranolazine (30 μM) inhibited I_Na in atrial and ventricular myocytes in a use-dependent manner consistent with preferential activated/inactivated state block. Ranolazine caused a significantly greater negative shift in voltage of half-maximal inactivation in atrial cells than in ventricular cells, the recovery from inactivation of I_Na was slowed by ranolazine to a greater extent in atrial myocytes than in ventricular cells, and ranolazine produced an instantaneous block that showed marked voltage dependence in atrial cells.

Conclusion

Differences exist between rabbit atrial and ventricular myocytes in the biophysical properties of I_Na. The more negative voltage dependence of I_Na activation and inactivation, together with trapping of the drug in the inactivated channel, underlies an atrial-selective action of ranolazine.

Ischemic Stroke in Nonvalvular Atrial Fibrillation at Warfarin Initiation

Background and Purpose—

Stroke risk may increase shortly after warfarin initiation in nonvalvular atrial fibrillation patients. Because of the brief period and limited number of events, large samples are needed to study this effect. We compared 30-day rates of ischemic stroke between nonvalvular atrial fibrillation patients initiating warfarin to nonwarfarin comparators using an insurance claims database.

Methods—

We identified nonvalvular atrial fibrillation patients via 1 inpatient/2 outpatient diagnosis claims from the MarketScan database, January 1, 2009, to December 31, 2010. We studied patients initiating warfarin using prescription claims and 1:1 matched 22 669 initiators to comparators based on age, sex, diagnosis date, and warfarin propensity score. Follow-up began on initiation date; patients were censored at discontinuation/switch of therapy, disenrollment, or end of the study. The median follow-up was 415 days. Cox regression was used to study differences in ischemic stroke risks between warfarin initiators and comparators while controlling for important prognostic factors.

Results—

Warfarin initiators were generally similar to comparators in clinical features but had higher CHADS 2 scores (1.26 versus 1.19). The first 30-day ischemic stroke rate was higher among warfarin initiators than comparators (1.47%/y (27/1836) versus 0.98%/y (18/1837); P =0.18) but lower subsequently (0.81%/y [134/16 543] versus 1.09%/y [406/37 248]; P =0.002). Multivariable regression confirmed a significant interaction between follow-up and warfarin use with the adjusted hazard ratios (95% confidence intervals) for warfarin/comparator as 1.46 (0.80–2.65) in the first 30 days and 0.70 (0.57–0.85) afterward.

Conclusions—

Warfarin effect was qualitatively different in the first 30 days after initiation than subsequently. This is consistent with a modest increase in stroke risk occurring briefly after starting warfarin.

The burden of proof: The current state of atrial fibrillation prevention and treatment trials

Atrial fibrillation (AF) is an age-related arrhythmia of enormous socioeconomic significance. In recent years, our understanding of the basic mechanisms that initiate and perpetuate AF has evolved rapidly, catheter ablation of AF has progressed from concept to reality, and recent studies suggest lifestyle modification may help prevent AF recurrence. Emerging developments in genetics, imaging, and informatics also present new opportunities for personalized care. However, considerable challenges remain. These include a paucity of studies examining AF prevention, modest efficacy of existing antiarrhythmic therapies, diverse ablation technologies and practice, and limited evidence to guide management of high-risk patients with multiple comorbidities. Studies examining the long-term effects of AF catheter ablation on morbidity and mortality outcomes are not yet completed. In many ways, further progress in the field is heavily contingent on the feasibility, capacity, and efficiency of clinical trials to incorporate the rapidly evolving knowledge base and to provide substantive evidence for novel AF therapeutic strategies. This review outlines the current state of AF prevention and treatment trials, including the foreseeable challenges, as discussed by a unique forum of clinical trialists, scientists, and regulatory representatives in a session endorsed by the Heart Rhythm Society at the 12th Global CardioVascular Clinical Trialists Forum in Washington, DC, December 3-5, 2015.

Association of SCN10A Polymorphisms with the Recurrence of Atrial Fibrillation after Catheter Ablation in a Chinese Han Population

The nonsynonymous SCN10A single nucleotide polymorphism (SNP) rs6795970 has been reported to associate with PR interval and atrial fibrillation (AF) and in strong linkage disequilibrium (LD) with the AF-associated SNP rs6800541. In this study, we investigated whether rs6795970 polymorphisms are associated with AF recurrence after catheter ablation. A total of 502 consecutive patients with AF who underwent catheter ablation were included. AF recurrence was defined as a documented episode of any atrial arrhythmias lasting ≥30 s after a blanking period of 3 months. AF recurrence was observed between 3 and 12 months after catheter ablation in 24.5% of the patients. There was a significant difference in the allele distribution (p = 7.86 × 10⁻⁵) and genotype distribution (p = 1.42 × 10⁻⁵) of rs6795970 between the AF recurrence and no recurrence groups. In a multivariate analysis, we identified the following independent predictors of AF recurrence: the rs6795970 genotypes in an additive model (OR 0.36, 95%CI 0.22~0.60, p = 7.04 × 10⁻⁵), a history of AF ≥36 months (OR 3.57, 95%CI 2.26~5.63, p = 4.33 × 10⁻⁸) and left atrial diameter (LAD) ≥40 mm (OR 1.85, 95%CI 1.08~3.19, p = 0.026). These data suggest that genetic variation in SCN10A may play an important role in predicting AF recurrence after catheter ablation in the Chinese Han population.

Reduced density and altered regulation of rat atrial L-type Ca2+ current in heart failure

Constitutive regulation by PKA has recently been shown to contribute to L-type Ca2+ current (ICaL) at the ventricular t-tubule in heart failure. Conversely, reduction in constitutive regulation by PKA has been proposed to underlie the downregulation of atrial ICaL in heart failure. The hypothesis that downregulation of atrial ICaL in heart failure involves reduced channel phosphorylation was examined. Anesthetized adult male Wistar rats underwent surgical coronary artery ligation (CAL, N=10) or equivalent sham-operation (Sham, N=12). Left atrial myocytes were isolated ~18 wk postsurgery and whole cell currents recorded (holding potential=-80 mV). ICaL activated by depolarizing pulses to voltages from -40 to +50 mV were normalized to cell capacitance and current density-voltage relations plotted. CAL cell capacitances were ~1.67-fold greater than Sham (P ≤ 0.0001). Maximal ICaL conductance (Gmax ) was downregulated more than 2-fold in CAL vs. Sham myocytes (P < 0.0001). Norepinephrine (1 μmol/l) increased Gmax >50% more effectively in CAL than in Sham so that differences in ICaL density were abolished. Differences between CAL and Sham Gmax were not abolished by calyculin A (100 nmol/l), suggesting that increased protein dephosphorylation did not account for ICaL downregulation. Treatment with either H-89 (10 μmol/l) or AIP (5 μmol/l) had no effect on basal currents in Sham or CAL myocytes, indicating that, in contrast to ventricular myocytes, neither PKA nor CaMKII regulated basal ICaL Expression of the L-type α1C-subunit, protein phosphatases 1 and 2A, and inhibitor-1 proteins was unchanged. In conclusion, reduction in PKA-dependent regulation did not contribute to downregulation of atrial ICaL in heart failure.NEW & NOTEWORTHY Whole cell recording of L-type Ca2+ currents in atrial myocytes from rat hearts subjected to coronary artery ligation compared with those from sham-operated controls reveals marked reduction in current density in heart failure without change in channel subunit expression and associated with altered phosphorylation independent of protein kinase A.

Association Between Posterior Left Atrial Adipose Tissue Mass and Atrial Fibrillation

Background—

Epicardial adipose tissue located close to the atrial wall can change the electric conduction of the left atrium, potentially leading to atrial fibrillation (AF). The aim of this study was to assess whether an increased atrial adipose tissue mass posterior to the left atrium is related to AF independent of demographical and cardiovascular risk factors.

Methods and Results—

Two hundred patients with AF and 200 patients without AF who underwent computed tomographic angiography were included. The posterior left atrial adipose tissue mass was quantified on computed tomographic angiography images as tissue with Hounsfield Units between −195 and −45. The adipose tissue mass was significantly larger in patients with AF compared with patients with sinus rhythm: 10.6±5.5 versus 4.7±3.5 g, P <0.001. In a multiple variable model (including age, body mass index, sex, coronary artery calcium score, diabetes mellitus, hypertension, hypercholesterolemia, family history of coronary artery disease, and known coronary artery disease), each gram increase of posterior left atrial adipose tissue was associated with 1.32 odds ratio of having AF (95% confidence interval, 1.22–1.43; P <0.001). Furthermore, the addition of the adipose tissue mass to the multiple variable analysis significantly increased the discriminatory ability to predict AF: increase in the area under the receiver operating characteristic, 0.88 (95% confidence interval, 0.84–0.91) versus 0.81 (0.76–0.85), P <0.001.

Conclusions—

Posterior left atrial adipose tissue mass is significantly larger in patients with AF versus without AF. An increase in adipose tissue was independently associated with AF and provided incremental value over well-known predictors of AF. These findings add to the hypothesis that the posterior left atrial adipose tissue mass contributes to structural and electric remodeling leading to AF.

Feasibility Testing of the Alert for AFib Intervention

Improving early detection and treatment of atrial fibrillation (AF) is critical because untreated AF is a major contributor to stroke and heart failure. We sought to generate knowledge about the feasibility of conducting a randomized controlled trial to test the effect of the Alert for AFib intervention on knowledge, attitudes, and beliefs about treatment-seeking for signs and symptoms of AF. Adults ≥65 years old (96% White) at risk for developing AF were randomized to receive the Alert for AFib intervention ( n = 40) or an attention control session ( n = 40). Feasibility goals for recruitment, participant retention, adherence, perceived satisfaction and burden, and intervention fidelity were met. From baseline to study completion, knowledge ( p = .005) and attitudes ( p < .001) about treatment-seeking improved more in the intervention group compared with the control group. Results support testing the effectiveness of the Alert for AFib intervention in a large trial.

Cardiac Autonomic Dysfunction and Incidence of Atrial Fibrillation: Results From 20 Years Follow-Up

BACKGROUND

Cardiac autonomic perturbations frequently antecede onset of paroxysmal atrial fibrillation (AF). Interventions that influence autonomic inputs to myocardium may prevent AF. However, whether low heart rate or heart rate variability (HRV), which are noninvasive measures of cardiac autonomic dysfunction, are associated with AF incidence is unclear.

OBJECTIVES

This study sought to study the association between HRV and risk of AF.

METHODS

This study included 11,715 middle-aged adults in the ARIC (Atherosclerosis Risk In Communities) cohort with heart rate and HRV measures obtained from 2-min electrocardiogram recordings performed at baseline (1987 to 1989). These measures included SD of normal-to-normal RR intervals, high-frequency (HF) (0.15 to 0.40 Hz), low-frequency (0.04 to 0.15 Hz), and the low-frequency/HF ratio (denoting a greater sympathetic to parasympathetic dominance). Incident AF cases were ascertained by electrocardiogram at ARIC follow-up visits, hospital discharge diagnosis, or death certificates through 2011.

RESULTS

During an average follow-up of 19.4 years, 1,580 or 13.5% of participants developed AF. A baseline heart rate <60 beats/min was associated modestly with an increased risk of AF. Lower overall HRV as well as increased sympathetic/parasympathetic tone were associated independently with a higher risk of AF; the hazard ratio for each 1 SD lower SD of normal-to-normal RR intervals was 1.14 (95% confidence interval: 1.08 to 1.21), for HF was 1.12 (95% confidence interval: 1.06 to 1.17), and for low frequency/HF was 1.08 (95% confidence interval: 1.03 to 1.14).

CONCLUSIONS

Cardiac autonomic dysfunction denoted by low resting short-term HRV was associated with higher AF incidence. A low heart rate may be associated with higher AF risk. Further studies are needed to determine whether interventions in the general population to restore autonomic balance may prevent AF.

Catheter ablation in patients with persistent atrial fibrillation

Catheter ablation is increasingly offered to patients who suffer from symptoms due to atrial fibrillation (AF), based on a growing body of evidence illustrating its efficacy compared with antiarrhythmic drug therapy. Approximately one-third of AF ablation procedures are currently performed in patients with persistent or long-standing persistent AF. Here, we review the available information to guide catheter ablation in these more chronic forms of AF. We identify the following principles: Our clinical ability to discriminate paroxysmal and persistent AF is limited. Pulmonary vein isolation is a reasonable and effective first approach for catheter ablation of persistent AF. Other ablation strategies are being developed and need to be properly evaluated in controlled, multicentre trials. Treatment of concomitant conditions promoting recurrent AF by life style interventions and medical therapy should be a routine adjunct to catheter ablation of persistent AF. Early rhythm control therapy has a biological rationale and trials evaluating its value are underway. There is a clear need to generate more evidence for the best approach to ablation of persistent AF beyond pulmonary vein isolation in the form of adequately powered controlled multi-centre trials.

Evaluation of a Prediction Model for the Development of Atrial Fibrillation in a Repository of Electronic Medical Records

Importance

Atrial fibrillation (AF) contributes to substantial morbidity, mortality, and health care expenditures. Accurate prediction of incident AF would enhance AF management and potentially improve patient outcomes.

Objective

To validate the AF risk prediction model originally developed by the Cohorts for Heart and Aging Research in Genomic Epidemiology-Atrial Fibrillation (CHARGE-AF) investigators using a large repository of electronic medical records (EMRs).

Design, Setting, and Participants

In this prediction model study, deidentified EMRs of 33 494 individuals 40 years or older who were white or African American and had no history of AF were reviewed and analyzed. The participants were followed up in the internal medicine outpatient clinics at Vanderbilt University Medical Center for incident AF from December 31, 2005, until December 31, 2010. Adjusting for differences in baseline hazard, the CHARGE-AF Cox proportional hazards model regression coefficients were applied to the EMR cohort. A simple version of the model with no echocardiographic variables was also evaluated. Data were analyzed from October 31, 2013, to January 31, 2014.

Main Outcomes and Measures

Incident AF. Predictors in the model included age, race, height, weight, systolic and diastolic blood pressure, treatment for hypertension, smoking status, type 2 diabetes, heart failure, history of myocardial infarction, left ventricular hypertrophy, and PR interval.

Results

Among the 33 494 participants, the median age was 57 (interquartile range, 49-67) years; 57% of patients were women, 43% were men, 85.7% were white, and 14.3% were African American. During the mean (SD) follow-up of 4.8 (0.9) years, 2455 individuals (7.3%) developed AF. Both models had poor calibration in the EMR cohort, with underprediction of AF among low-risk individuals and overprediction of AF among high-risk individuals (10th and 90th percentiles for predicted probability of incident AF, 0.005 and 0.179, respectively). The full CHARGE-AF model had a C index of 0.708 (95% CI, 0.699-0.718) in our cohort. The simple model had similar discrimination (C index, 0.709; 95% CI, 0.699-0.718; P = .70 for difference between models).

Conclusions and Relevance

Despite reasonable discrimination, the CHARGE-AF models showed poor calibration in this EMR cohort. This study highlights the difficulties of applying a risk model derived from prospective cohort studies to an EMR cohort and suggests that these AF risk prediction models be used with caution in the EMR setting. Future risk models may need to be developed and validated within EMR cohorts.

Two-year outcomes of patients with newly diagnosed atrial fibrillation: results from GARFIELD-AF

AIMS

The relationship between outcomes and time after diagnosis for patients with non-valvular atrial fibrillation (NVAF) is poorly defined, especially beyond the first year.

METHODS AND RESULTS

GARFIELD-AF is an ongoing, global observational study of adults with newly diagnosed NVAF. Two-year outcomes of 17 162 patients prospectively enrolled in GARFIELD-AF were analysed in light of baseline characteristics, risk profiles for stroke/systemic embolism (SE), and antithrombotic therapy. The mean (standard deviation) age was 69.8 (11.4) years, 43.8% were women, and the mean CHA2DS2-VASc score was 3.3 (1.6); 60.8% of patients were prescribed anticoagulant therapy with/without antiplatelet (AP) therapy, 27.4% AP monotherapy, and 11.8% no antithrombotic therapy. At 2-year follow-up, all-cause mortality, stroke/SE, and major bleeding had occurred at a rate (95% confidence interval) of 3.83 (3.62; 4.05), 1.25 (1.13; 1.38), and 0.70 (0.62; 0.81) per 100 person-years, respectively. Rates for all three major events were highest during the first 4 months. Congestive heart failure, acute coronary syndromes, sudden/unwitnessed death, malignancy, respiratory failure, and infection/sepsis accounted for 65% of all known causes of death and strokes for <10%. Anticoagulant treatment was associated with a 35% lower risk of death.

CONCLUSION

The most frequent of the three major outcome measures was death, whose most common causes are not known to be significantly influenced by anticoagulation. This suggests that a more comprehensive approach to the management of NVAF may be needed to improve outcome. This could include, in addition to anticoagulation, interventions targeting modifiable, cause-specific risk factors for death.

CLINICAL TRIAL REGISTRATION

http://www.clinicaltrials.gov. Unique identifier: NCT01090362.

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.

Light to Moderate Habitual Alcohol Consumption Is Associated with Subclinical Ventricular and Left Atrial Mechanical Dysfunction in an Asymptomatic Population: Dose-Response and Propensity Analysis

BACKGROUND

The effects of light to moderate alcohol consumption on cardiac mechanics remain poorly understood. The aim of this study was to investigate the dose-response relationship between alcohol consumption and left ventricular (LV) and left atrial (LA) function using myocardial deformation.

METHODS

In total 3,946 asymptomatic participants (mean age, 49.7 ± 10.7 years; 65% men) were consecutively studied using comprehensive echocardiography and two-dimensional speckle-tracking in a cross-sectional, retrospective manner. Global LV longitudinal and circumferential strain and LA strain were assessed and related to habitual alcohol consumption pattern (fewer than one, one to six, or more than six drinks per week) before and after propensity matching.

RESULTS

With increasing weekly alcohol consumption, participants displayed greater LV eccentric remodeling, impaired diastolic function, and more attenuated global longitudinal strain, LA strain (adjusted coefficients, -1.07 [95% CI, -1.95 to -0.19] and -3.73 [95% CI, -5.36 to -2.11]), and early diastolic strain rates (adjusted coefficients, 0.07 [95% CI, 0.03-0.11] and 0.33 [95% CI, 0.24-0.42]) for one to six and more than six drinks per week, respectively (P < .05 for all) in a dose-response manner. Participants with recent alcohol abstinence displayed cardiac mechanics intermediate between those of nondrinkers and current drinkers. After propensity matching (n = 1,140), participants currently consuming more than one drink per week continued to have significantly attenuated global longitudinal strain and all LA mechanics compared with those consuming fewer than one drink per week (P < .05 for all).

CONCLUSIONS

Habitual alcohol consumption, even at light to moderate doses, is associated with both reduced LV and LA mechanics in a dose-dependent manner. Whether such observations are reversible or related to future atrial fibrillation deserves further study.

Impact of Warfarin on Atrial-Fibrillation Outcomes Related to Economic Consumption Patterns: Hospitalization, Cost, and Mortality may be Predictable and Modifiable at the Population Level

INTRODUCTION

Warfarin reduces atrial fibrillation (AF)-related strokes and may impact mortality, hospitalizations, and costs. This study investigated the possibility that patterns of warfarin consumption are associated with the frequency of acute events.

METHODS

Annual cost profiles of 9.2 million Medicare beneficiaries with AF were analyzed to identify patterns of benefits consumption from 2000 through 2010. Beneficiaries were divided into five consumption clusters based upon their annual cost profiles, ranging from crisis consumers at the high end to low consumers. Resource-utilization patterns and outcome differences were calculated between AF beneficiaries who received warfarin and those who did not. Propensity score-matched analysis was performed to reduce selection bias.

RESULTS

The annual percentages of beneficiaries and expenditures that differentiated each cluster showed stable patterns. Warfarin use influenced consumption patterns and outcomes. The most important financial difference between higher and lower consumers was inpatient cost. AF beneficiaries on warfarin had lower annual cost profiles and had a higher propensity to persist in or migrate to consumption clusters with comparatively small reimbursement claims and lower hospitalization risks. AF beneficiaries not on warfarin had higher cost and mortality.

CONCLUSIONS

These data signal that a nontrivial portion of acute events (hospitalization and mortality) are amenable to medical intervention (warfarin). When acute events are amenable to medical intervention and occur at a higher frequency because guidelines have not been applied evenly across affected populations, it is appropriate to define those occurrences as disparities associated with systemic failure in evidence-based medicine. Quality-improvement initiatives that reduce therapeutic disparities may result in lower cost and improved outcomes.

FUNDING

No funding or sponsorship was received for this study or publication of this article.

The Use of Statins in the Treatment and Prevention of Atrial Fibrillation

The hydroxy-methyl-glutaryl-CoA reductase inhibitors (statins) are used extensively in the treatment of hyperlipidemia and in the primary and secondary prevention of cardiovascular and cerebrovascular diseases. Statins have also been demonstrated to confer secondary pleiotropic benefits in a variety of other disease processes, including a potential advantage in treating and preventing atrial fibrillation. These effects are primarily due to the up-regulation of endothelial nitric oxide synthase activity and a decrease in nicotinamide adenine dinucleotide phosphate oxidase production, which leads to downstream effects that improve the electromechanical function of atrial and myocardial tissue. The following serves as a focused and updated review of the published clinical data regarding the pleiotropic effects of statins in atrial fibrillation.

Major bleeding risk among non-valvular atrial fibrillation patients initiated on apixaban, dabigatran, rivaroxaban or warfarin: a "real-world" observational study in the United States

BACKGROUND

Limited data are available about the real-world safety of non-vitamin K antagonist oral anticoagulants (NOACs).

OBJECTIVES

To compare the major bleeding risk among newly anticoagulated non-valvular atrial fibrillation (NVAF) patients initiating apixaban, warfarin, dabigatran or rivaroxaban in the United States.

METHODS AND RESULTS

A retrospective cohort study was conducted to compare the major bleeding risk among newly anticoagulated NVAF patients initiating warfarin, apixaban, dabigatran or rivaroxaban. The study used the Truven MarketScan(®) Commercial & Medicare supplemental US database from 1 January 2013 through 31 December 2013. Major bleeding was defined as bleeding requiring hospitalisation. Cox model estimated hazard ratios (HRs) of major bleeding were adjusted for age, gender, baseline comorbidities and co-medications. Among 29 338 newly anticoagulated NVAF patients, 2402 (8.19%) were on apixaban; 4173 (14.22%) on dabigatran; 10 050 (34.26%) on rivaroxaban; and 12 713 (43.33%) on warfarin. After adjusting for baseline characteristics, initiation on warfarin [adjusted HR (aHR): 1.93, 95% confidence interval (CI): 1.12-3.33, P=.018] or rivaroxaban (aHR: 2.19, 95% CI: 1.26-3.79, P=.005) had significantly greater risk of major bleeding vs apixaban. Dabigatran initiation (aHR: 1.71, 95% CI: 0.94-3.10, P=.079) had a non-significant major bleeding risk vs apixaban. When compared with warfarin, apixaban (aHR: 0.52, 95% CI: 0.30-0.89, P=.018) had significantly lower major bleeding risk. Patients initiating rivaroxaban (aHR: 1.13, 95% CI: 0.91-1.41, P=.262) or dabigatran (aHR: 0.88, 95% CI: 0.64-1.21, P=.446) had a non-significant major bleeding risk vs warfarin.

CONCLUSION

Among newly anticoagulated NVAF patients in the real-world setting, initiation with rivaroxaban or warfarin was associated with a significantly greater risk of major bleeding compared with initiation on apixaban. When compared with warfarin, initiation with apixaban was associated with significantly lower risk of major bleeding. Additional observational studies are required to confirm these findings.

Central Sleep-disordered Breathing Predicts Incident Atrial Fibrillation in Older Men

RATIONALE

Although research supports a sleep-disordered breathing and atrial fibrillation association, prospective data examining sleep-disordered breathing predicting incident atrial fibrillation are lacking.

OBJECTIVES

To investigate sleep-disordered breathing indices as predictors of incident atrial fibrillation.

METHODS

A cohort (n = 843) of ambulatory older men without prevalent atrial fibrillation was assessed for baseline sleep indices: apnea-hypopnea index, central sleep apnea (central apnea index, ≥5 vs. <5), central sleep apnea or Cheyne-Stokes respiration, obstructive apnea-hypopnea index, and percentage of sleep time with less than 90% oxygen saturation. Incident clinically symptomatic adjudicated or self-reported atrial fibrillation outcome was ascertained (mean follow-up, 6.5 ± 0.7 yr). We used logistic regression models adjusted for age, race, body mass index, cardiopulmonary disease, alcohol use, pacemaker, cholesterol, cardiac medications, and alternate apnea type for obstructive and central apnea. Age interaction terms and median age-stratified analyses were performed.

MEASUREMENTS AND MAIN RESULTS

Central sleep apnea (odds ratio [OR], 2.58; 95% confidence interval [CI], 1.18-5.66) and Cheyne-Stokes respiration with central sleep apnea (OR, 2.27; 95% CI, 1.13-4.56), but not obstructive apnea or hypoxemia, predicted incident atrial fibrillation. Central apnea, Cheyne-Stokes respiration, and sleep-disordered breathing-age interaction terms were significant (P < 0.05). Unlike the case with younger participants, among participants aged 76 years or older (albeit with small atrial fibrillation counts), atrial fibrillation was related to central apnea (OR, 9.97; 95% CI, 2.72-36.50), Cheyne-Stokes respiration with central apnea (OR, 6.31; 95% CI, 1.94-20.51), and apnea-hypopnea index (OR, 1.22; 95% CI, 1.08-1.39 [per 5-unit increase]).

CONCLUSIONS

In older men, central apnea and Cheyne-Stokes respiration predicted increased atrial fibrillation risk, with findings being strongest in older participants in whom overall sleep-disordered breathing also increased atrial fibrillation risk.

A comparison of the CHARGE-AF and the CHA2DS2-VASc risk scores for prediction of atrial fibrillation in the Framingham Heart Study

BACKGROUND

Atrial fibrillation (AF) affects more than 33 million individuals worldwide and increases risks of stroke, heart failure, and death. The CHARGE-AF risk score was developed to predict incident AF in three American cohorts and it was validated in two European cohorts. The CHA2DS2-VASc risk score was derived to predict risk of stroke, peripheral embolism, and pulmonary embolism in individuals with AF, but it has been increasingly used for AF risk prediction. We compared CHARGE-AF risk score versus CHA2DS2-VASc risk score for incident AF risk in a community-based cohort.

METHODS AND RESULTS

We studied Framingham Heart Study participants aged 46 to 94 years without prevalent AF and with complete covariates. We predicted AF risk using Fine-Gray proportional sub-distribution hazards regression. We used the Wald χ(2) statistic for model fit, C-statistic for discrimination, and Hosmer-Lemeshow (HL) χ(2) statistic for calibration. We included 9722 observations (mean age 63.9 ± 10.6 years, 56% women) from 4548 unique individuals: 752 (16.5%) developed incident AF and 793 (17.4%) died. The mean CHARGE-AF score was 12.0 ± 1.2 and the sub-distribution hazard ratio (sHR) for AF per unit increment was 2.15 (95% CI, 99-131%; P < .0001). The mean CHA2DS2-VASc score was 2.0 ± 1.5 and the sHR for AF per unit increment was 1.43 (95% CI, 37%-51%; P < .0001). The CHARGE-AF model had better fit than CHA2DS2-VASc (Wald χ(2) = 403 vs 209, both with 1 df), improved discrimination (C-statistic = 0.75, 95% CI, 0.73-0.76 vs C-statistic = 0.71, 95% CI, 0.69-0.73), and better calibration (HL χ(2) = 5.6, P = .69 vs HL χ(2) = 28.5, P < .0001).

CONCLUSION

The CHARGE-AF risk score performed better than the CHA2DS2-VASc risk score at predicting AF in a community-based cohort.

Risk of dementia and death in patients with atrial fibrillation: A competing risk analysis of a population-based cohort

BACKGROUND

Previous studies have stated that atrial fibrillation (AF) is associated with a higher risk of dementia. However, none have examined the competition between death and incident dementia in patients with AF. We evaluated the risk of incident dementia in patients with AF in comparison to people without this arrhythmia, considering of the competing risk of death.

METHODS

AF and non-AF cohorts were identified using the large administrative database of the Lombardy Region and followed for ten years. Patients with incident dementia were identified if they had an ICD 9 code referring to dementia at hospital discharge or a prescription for any anti-dementia drug. The association of AF with dementia or death was assessed with the multivariable Cox proportional-regression model, sensitivity analysis with a 1:1 propensity score matching and competing-risk analysis.

RESULTS

In 2003 a total of 27,431 patients were hospitalized for AF in the Lombardy Region, while the cohort of non-AF counted 1,600,200 people. AF was associated with a higher risk of dementia (17%) and death (51%) at multivariable Cox analysis. These results were confirmed by the model fitted after propensity score matching. However, competing risk analysis found the association between AF and incident dementia was no longer significant (HR 0.99; 95% CI 0.94-1.04).

CONCLUSIONS

In this real-world population the association between AF and dementia was no longer statistically significant when death was considered a competing risk.

Carotid Intima-Media Thickness and Arterial Stiffness and the Risk of Atrial Fibrillation: The Atherosclerosis Risk in Communities (ARIC) Study, Multi-Ethnic Study of Atherosclerosis (MESA), and the Rotterdam Study

BACKGROUND

We evaluated the association of carotid intima-media thickness (cIMT), carotid plaque, carotid distensibility coefficient (DC), and aortic pulse wave velocity (PWV) with incident atrial fibrillation (AF) and their role in improving AF risk prediction beyond the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE)-AF risk score.

METHODS AND RESULTS

We analyzed data from 3 population-based cohort studies: Atherosclerosis Risk in Communities (ARIC) Study (n=13 907); Multi-Ethnic Study of Atherosclerosis (MESA; n=6640), and the Rotterdam Study (RS; n=5220). We evaluated the association of arterial indices with incident AF and computed the C-statistic, category-based net reclassification improvement (NRI), and relative integrated discrimination improvement (IDI) of incorporating arterial indices into the CHARGE-AF risk score (age, race, height weight, systolic and diastolic blood pressure, antihypertensive medication use, smoking, diabetes, previous myocardial infarction, and previous heart failure). Higher cIMT (meta-analyzed hazard ratio [95% CI] per 1-SD increment, 1.12 [1.08-1.16]) and presence of carotid plaque (1.30 [1.19-1.42]) were associated with higher AF incidence after adjustment for CHARGE-AF risk-score variables. Lower DC and higher PWV were associated with higher AF incidence only after adjustment for the CHARGE-AF risk-score variables excepting height, weight, and systolic and diastolic blood pressure. Addition of cIMT or carotid plaque marginally improved CHARGE-AF score prediction as assessed by the relative IDI (estimates, 0.025-0.051), but not when assessed with the C-statistic and NRI.

CONCLUSIONS

Higher cIMT, presence of carotid plaque, and greater arterial stiffness are associated with higher AF incidence, indicating that atherosclerosis and arterial stiffness play a role in AF etiopathogenesis. However, arterial indices only modestly improve AF risk prediction.

North American Thrombosis Forum, AF Action Initiative Consensus Document

The North American Thrombosis Forum Atrial Fibrillation Action Initiative consensus document is a comprehensive yet practical briefing document focusing on stroke and bleeding risk assessment in patients with atrial fibrillation, as well as recommendations regarding anticoagulation options and management. Despite the breadth of clinical trial data and guideline recommendation updates, many clinicians continue to struggle to synthesize the disparate information available. This problem slows the uptake and utilization of updated risk prediction tools and adoption of new oral anticoagulants. This document serves as a practical and educational reference for the entire medical community involved in the care of patients with atrial fibrillation.