Comprehensive risk reduction in patients with atrial fibrillation: emerging diagnostic and therapeutic options--a report from the 3rd Atrial Fibrillation Competence NETwork/European Heart Rhythm Association consensus conference

Late onset of atrial fibrillation in patients undergoing mitral valve repair for type II dysfunction

BACKGROUND

There are few reports regarding factors related to late-onset of atrial fibrillation (Af) after mitral valve repair, which can compromise long-term outcome. We analyzed the risk factors for late Af after mitral valve repair.

METHODS AND RESULTS

Between 2001 and 2015, 318 patients (214 males; median, 57.7 years) underwent mitral valve repair for degenerative mitral insufficiency (MI) without concomitant aortic valve disease in our institute. Patients with a history of paroxysmal or chronic Af preoperatively were excluded. Serial follow-up echocardiography was used to evaluate cardiac function. The follow-up rate was 99%. The mean follow-up period was 6.0±4.1 years. There was no early death and there were nine late deaths. A total of 29 (9.1%) patients developed late Af. Freedom from late Af was 94.0% at 5 years and 82.9% at 10 years. Small ring annuloplasty, left atrial diameter, and pressure half time, which were measured at follow-up echocardiography, were considered as significant (p<0.05) risk factors for late Af. Patients who had late Af developed recurrent MI more frequently than those who did not (p<0.05).

CONCLUSIONS

Remodeling of the atrium caused by functional mitral stenosis is important for late Af, as well as recurrent MI. To prevent these problems, avoiding selection of a small ring at primary mitral repair for type II dysfunction and durable repair are required.

Clinical significance of atrial high-rate episodes for thromboembolic events in Japanese population

OBJECTIVE

The clinical significance of atrial high-rate episodes (AHREs) detected by cardiac devices among patients with implantable pacemakers has recently emerged. However, the relationship between AHREs and ischaemic stroke and systemic embolism (SE) is not well understood in the Japanese population.

METHODS

This study included 343 patients with pacemakers capable of continuous atrial rhythm monitoring (167 males; mean age, 80±7 years). Atrial tachyarrhythmia detection was programmed to the nominal setting of each device, and AHRE was defined as any episode of sustained atrial tachyarrhythmia lasting for more than 6 min. Thromboembolic risk was defined based on the CHADS2 score.

RESULTS

During the follow-up period (52±30 months), 165 (48%) patients had at least one episode of AHREs, and 19 (6%) patients experienced stroke/SE. Among patients who experienced stroke/SE, 14 had AHREs before the stroke/SE. AHREs were significantly associated with stroke/SE (HR 2.87; 95% CI 1.10 to 8.90; p=0.03). Subgroup analysis conducted to investigate the impact of the CHADS2 score severity on stroke/SE revealed that AHREs were not associated with stroke/SE in patients with low or intermediate thromboembolic risk (CHADS2 score 0-2; n=217). In contrast, among patients with high thromboembolic risk (CHADS2 score>2; n=126), there was a significant association between AHREs and the incidence of stroke/SE (HR 3.73; 95% CI 1.06 to 13.1; p=0.04).

CONCLUSION

AHREs detected by pacemaker were associated with ischaemic stroke/SE in the Japanese population. However, this association was observed only in the high thromboembolic risk group.

The future of atrial fibrillation management: integrated care and stratified therapy

Atrial fibrillation is one of the major cardiovascular health problems: it is a common, chronic condition, affecting 2-3% of the population in Europe and the USA and requiring 1-3% of health-care expenditure as a result of stroke, sudden death, heart failure, unplanned hospital admissions, and other complications. Early diagnosis of atrial fibrillation, ideally before the first complication occurs, remains a challenge, as shown by patients who are only diagnosed with the condition when admitted to hospital for acute cardiac decompensation or stroke. Once diagnosed, atrial fibrillation requires chronic, multidimensional management in five domains (acute management, treatment of underlying and concomitant cardiovascular conditions, stroke prevention therapy, rate control, and rhythm control). The consistent provision of these treatment options to all patients with atrial fibrillation is difficult, despite recent improvements in organisation of care, knowledge about atrial fibrillation, and treatment options. Integrated care models that provide patient-centred care in, or close to, the patient's community while maintaining access to all specialist treatment options, emerge as the best approach to achieve consistent delivery of these chronic treatments to all patients with atrial fibrillation. Ongoing research efforts will establish when to initiate oral anticoagulation in patients with device-detected atrial high-rate episodes, quantify the prognostic effect of early and comprehensive rhythm control therapy, including atrial fibrillation ablation, and delineate optimum methods to reduce bleeding complications in patients treated with anticoagulation. Additionally, research efforts are needed to define different types of atrial fibrillation on the basis of the main causes of atrial fibrillation to pave the way for the clinical development of stratified atrial fibrillation therapy.

Probing oral anticoagulation in patients with atrial high rate episodes: Rationale and design of the Non-vitamin K antagonist Oral anticoagulants in patients with Atrial High rate episodes (NOAH-AFNET 6) trial

Oral anticoagulation prevents ischemic strokes in patients with atrial fibrillation (AF). Early detection of AF and subsequent initiation of oral anticoagulation help to prevent strokes in AF patients. Implanted cardiac pacemakers and defibrillators allow seamless detection of atrial high rate episodes (AHRE), but the best antithrombotic therapy in patients with AHRE is not known.

Rationale

Stroke risk is higher in pacemaker patients with AHRE than in those without, but the available data also show that stroke risk in patients with AHRE is lower than in patients with AF. Furthermore, only a minority of patients with AHRE will develop AF, many strokes occur without a temporal relation to AHRE, and AHRE can reflect other arrhythmias than AF or artifacts. An adequately powered controlled trial of oral anticoagulation in patients with AHRE is needed.

Design

The Non–vitamin K antagonist Oral anticoagulants in patients with Atrial High rate episodes (NOAH–AFNET 6 ) trial tests whether oral anticoagulation with edoxaban is superior to prevent the primary efficacy outcome of stroke or cardiovascular death compared with aspirin or no antithrombotic therapy based on evidence-based indications. The primary safety outcome will be major bleeding. NOAH–AFNET 6 will randomize 3,400 patients with AHRE, but without documented AF, aged ≥65 years with at least 1 other stroke risk factor, to oral anticoagulation therapy (edoxaban) or no anticoagulation. All patients will be followed until the end of this investigator-driven, prospective, parallel-group, randomized, event-driven, double-blind, multicenter phase IIIb trial. Patients will be censored when they develop AF and offered open-label anticoagulation. The sponsor is the Atrial Fibrillation NETwork (AFNET). The trial is supported by the DZHK (German Centre for Cardiovascular Research), the BMBF (German Ministry of Education and Research), and Daiichi Sankyo Europe.

Conclusion

NOAH–AFNET 6 will provide robust information on the effect of oral anticoagulation in patients with atrial high rate episodes detected by implanted devices.

Atrial-selective K+ channel blockers: potential antiarrhythmic drugs in atrial fibrillation?

In the wake of demographic change in Western countries, atrial fibrillation has reached an epidemiological scale, yet current strategies for drug treatment of the arrhythmia lack sufficient efficacy and safety. In search of novel medications, atrial-selective drugs that specifically target atrial over other cardiac functions have been developed. Here, I will address drugs acting on potassium (K⁺) channels that are either predominantly expressed in atria or possess electrophysiological properties distinct in atria from ventricles. These channels include the ultra-rapidly activating, delayed outward-rectifying Kv1.5 channel conducting I_Kur, the acetylcholine-activated inward-rectifying Kir3.1/Kir3.4 channel conducting I_K,ACh, the Ca²⁺-activated K⁺ channels of small conductance (SK) conducting I_SK, and the two-pore domain K⁺ (K2P) channels (tandem of P domains, weak inward-rectifying K⁺ channels (TWIK-1), TWIK-related acid-sensitive K⁺ channels (TASK-1 and TASK-3)) that are responsible for voltage-independent background currents I_TWIK-1, I_TASK-1, and I_TASK-3. Direct drug effects on these channels are described and their putative value in treatment of atrial fibrillation is discussed. Although many potential drug targets have emerged in the process of unravelling details of the pathophysiological mechanisms responsible for atrial fibrillation, we do not know whether novel antiarrhythmic drugs will be more successful when modulating many targets or a single specific one. The answer to this riddle can only be solved in a clinical context.

SERUM OSTEOPONTIN LEVEL IS ASSOCIATED WITH PRESENCE OF ATRIAL FIBRILLATION IN CALCIFIC AORTIC VALVE STENOSIS

Identification of risk factors associated with presence of atrial fibrillation (AF) in patients with aortic valve stenosis (AS) remains to be unraveled.The aim of the study was to investigate relationship between profibrotic biomarkers and presence of AF in AS patientsMethods. 191 patients (29,8% male, 77,7±0,59 years) with AS (defined as aortic valve area (AVA) ≤ 2,0 sm2) were enrolled in the study. Clinical, echocardiographic and biochemical variables, including serum TGFβ1 and osteopontin levels were compared between 2 groups of patients: with and without AF. Results. 83(36,5%) of AS patients had AF. In logistic regression models independent associations between AVA index (p=0,040), left atrial volume (p=0,021), OPN (р=0,009) and presence of AF were found. Patients with serum OPN level > 10,05 ng/ml had twice more higher AF incidence comparedto patients with serum OPN level ≤ 10,05 ng/ml (53,8% and 29,2%, respectively, p=0,020).Conclusion. Serum OPN level was independently associated with presence of AF in AS patients, thus we speculate on it’s predominant profibrotic role in the left atrium.

Auscultatory versus oscillometric blood pressure measurement in patients with atrial fibrillation and arterial hypertension

BACKGROUND

The aim of our study was to investigate the reliability of automated oscillometric blood pressure (BP) monitoring in the presence and absence of atrial fibrillation (AF) in hypertensive patients.

METHODS

BP was measured and compared in 71 randomly selected patients with AF and arterial hypertension diagnosis, 4 times each by auscultatory and oscillometric (Microlife BP A6 PC with AF detection system) methods.

RESULTS

Study included 71 patients: 36 males (mean age 67.4 years) and 35 females (70.2 years). At the time of BP measuring procedure, 36 patients were in sinus rhythm (SR) and 35 in AF. In SR patients mean systolic blood pressure (SBP) was 132 ± 17.9 mmHg with auscultatory method (AM), 137.4 ± 19.4 mmHg with oscillometric method (OM); mean diastolic BP was 77.1 ± 10.9 mmHg (AM), 78.5 ± 12.2 mmHg (OM), in AF patients mean SBP was 127.5 ± 15.1 mmHg (AM), 133.6 ± 17.4 mmHg (OM); mean diastolic BP was 81.4 ± 9.9 mmHg (AM), 83.5 ± 11.8 mmHg (OM), p = 0.037. The averages of differences for SBP and DBP in sinus rhythm group were (-5.3 mmHg (95% limits of agreement -27.2 - 16.6)) and (-1.4 mmHg (95% limits of agreement -12.8 - 10.0)), respectively. In patients with AF the averages of differences for SBP and DBP were (-6.1 mmHg (95% limits of agreement -23.9 - 11.7)) and (-2.1 mmHg (95% limits of agreement -12.9 - 8.7)), respectively.

CONCLUSIONS

The oscillometric device validated for patients with AF on average gives 5.3 mmHg higher systolic BP values for patients with SR and 6.3 mmHg higher BP values for patients with AF. However, the limits of agreement between two methods reveal wide range of random error rates which is a questionable topic in clinical practice, as it could possibly affect the treatment of arterial hypertension in patients with AF.

Cancer antigen-125 plasma level as a biomarker of new-onset atrial fibrillation in postmenopausal women

OBJECTIVE

Plasma cancer antigen (CA)-125 is a tumour marker recently shown to be associated with systolic heart failure and new-onset atrial fibrillation (AF) after myocardial infarction. However, no reports have described the relationship between CA-125 and new-onset AF in healthy postmenopausal women. The aim of the present study was to evaluate the relationship between CA-125 and new-onset AF in postmenopausal women.

METHODS

Between 2005 and 2015, 2086 women, including 1012 postmenopausal women, visited our hospital for annual health check-ups. We excluded patients with systolic dysfunction, chronic inflammatory disease, chronic obstructive pulmonary disease, histories of AF or neoplastic diseases. A total of 746 postmenopausal women underwent thorough physical examinations, including those for biomarkers such as brain natriuretic peptide, high-sensitivity C-reactive protein (hs-CRP) and CA-125.

RESULTS

During the 10-year observation period, AF was documented in 31 participants (4.2%). The mean age of participants developing AF (75±6 years) was higher than that of those without AF (68±8 years). Participants developing AF showed significantly higher CA-125 (11.4±6.3 U/mL) and hs-CRP (0.10±0.11 mg/dL) levels than did those without AF (7.7±3.2 U/mL, p<0.01; 0.07±0.08 mg/dL, p<0.05). Cox regression analyses revealed ageing (HR 1.3; 95% CI 1.08 to 1.57; p<0.01) and plasma CA-125 levels (HR 1.29; 95% CI 1.10 to 1.51; p=0.02) as independent predictors of AF.

CONCLUSIONS

High CA-125 levels might be associated with new-onset AF in healthy postmenopausal women.

Evaluation of atrial fibrillation management and cardiovascular risk profile in atrial fibrillation patients: A cross-sectional survey

OBJECTIVE

The aim of this study to investigate the most frequent risk factors of atrial fibrillation (AF), co-morbidities, complications associated with AF and the use of anticoagulants and other medications in patients who were referred to university hospitals in Lithuania.

MATERIALS AND METHODS

This cross-sectional study enrolled consecutive inpatients and outpatients with AF presenting to cardiologists in the two biggest Lithuanian university hospitals from November 2013 to May 2014. AF diagnosis was confirmed by a 12-lead ECG or 24-h Holter with an episode duration of >30s.

RESULTS

A total number of 575 patients were recruited, and complete data on clinical subtype were available for 515 patients (mean age of 70.7 years; 48.5% of women). Permanent AF was the most frequent type of AF (46.6%). Common comorbidities were hypertension (85.8%), heart failure (77.9%) and coronary artery disease (51.8%). Amiodarone was the most common antiarrhythmic agent used in 14.6% of the patients, while beta-blockers and digoxin were the most often used rate control drugs (59.6% and 10.7%, respectively). Oral anticoagulants were used by 53.3% of the patients; of them, 95.6% used vitamin K antagonists, while non-vitamin K antagonist were used by only 4.4%. The INR within a therapeutic range (2.0-3.0) was documented in 19.2% of the patients. Other antithrombotic drugs such as aspirin and clopidogrel were used in 13.7% and 2.0% of the patients, respectively; dual antiplatelet treatment was administered in 6.2% of the patients. Of the entire cohort, the mean CHA₂DS₂-VASc score was 3.97±1.6 and the mean HAS-BLED score was 2.25±1.0.

CONCLUSIONS

Compliance with the treatment guidelines remains suboptimal and further patient education is needed.

Atrial high-rate episodes and stroke prevention

While the benefit of oral anticoagulants (OACs) for stroke prevention in patients with atrial fibrillation (AF) is well established, it is not known whether oral anticoagulation is indicated in patients with atrial high-rate episodes (AHRE) recorded on a cardiac implantable electronic device, sometimes also called subclinical AF, and lasting for at least 6 min in the absence of clinically diagnosed AF. Clinical evidence has shown that short episodes of rapid atrial tachycarrhythmias are often detected in patients presenting with stroke and transient ischaemic attack. Patients with AHRE have a higher likelihood of suffering from subsequent strokes, but their stroke rate seems lower than in patients with diagnosed AF, and not all AHRE episodes correspond to AF. The prognostic and pathological significance of AHRE is not yet fully understood. Clinical trials of OAC therapy are being conducted to determine whether therapeutic intervention would be beneficial to patients experiencing AHRE in terms of reducing the risk of stroke.

Clinical, biomarker, and genetic predictors of specific types of atrial fibrillation in a community-based cohort: data of the PREVEND study

Aims

Atrial fibrillation (AF) may present variously in time, and AF may progress from self-terminating to non-self-terminating AF, and is associated with impaired prognosis. However, predictors of AF types are largely unexplored. We investigate the clinical, biomarker, and genetic predictors of development of specific types of AF in a community-based cohort.

Methods

We included 8042 individuals (319 with incident AF) of the PREVEND study. Types of AF were compared, and multivariate multinomial regression analysis determined associations with specific types of AF.

Results

Mean age was 48.5 ± 12.4 years and 50% were men. The types of incident AF were ascertained based on electrocardiograms; 103(32%) were classified as AF without 2-year recurrence, 158(50%) as self-terminating AF, and 58(18%) as non-self-terminating AF. With multivariate multinomial logistic regression analysis, advancing age (P< 0.001 for all three types) was associated with all AF types, male sex was associated with AF without 2-year recurrence and self-terminating AF (P= 0.031 and P= 0.008, respectively). Increasing body mass index and MR-proANP were associated with both self-terminating (P= 0.009 and P< 0.001) and non-self-terminating AF (P= 0.003 and P< 0.001). The only predictor associated with solely self-terminating AF is prescribed anti-hypertensive treatment (P= 0.019). The following predictors were associated with non-self-terminating AF; lower heart rate (P= 0.018), lipid-lowering treatment prescribed (P= 0.009), and eGFR <60 mL/min/1.73 m2 (P= 0.006). Three known AF-genetic variants (rs6666258, rs6817105, and rs10821415) were associated with self-terminating AF.

Conclusions

We found clinical, biomarker and genetic predictors of specific types of incident AF in a community-based cohort. The genetic background seems to play a more important role than modifiable risk factors in self-terminating AF.

Prognostic Impact of Atrial Fibrillation and New Risk Score of Its Onset in Patients at High Risk of Heart Failure - A Report From the CHART-2 Study

BACKGROUND

The prognostic impact of atrial fibrillation (AF) among patients at high risk for heart failure (HF) remains unclear. In addition, there is no risk estimation model for AF development in these patients.

METHODS AND RESULTS

The present study included 5,382 consecutive patients at high risk of HF enrolled in the CHART-2 Study (n=10,219). At enrollment, 1,217 (22.6%) had AF, and were characterized, as compared with non-AF patients, by higher age, lower estimated glomerular filtration rate, higher B-type natriuretic peptide (BNP) level and lower left ventricular ejection fraction. A total of 116 non-AF patients (2.8%) newly developed AF (new AF) during the median 3.1-year follow-up. AF at enrollment was associated with worse prognosis for both all-cause death and HF hospitalization (adjusted hazard ratio (aHR) 1.31, P=0.027 and aHR 1.74, P=0.001, for all-cause death and HF hospitalization, respectively) and new AF was associated with HF hospitalization (aHR 4.54, P<0.001). We developed a risk score with higher age, smoking, pulse pressure, lower eGFR, higher BNP, aortic valvular regurgitation, LV hypertrophy, and left atrial and ventricular dilatation on echocardiography, which effectively stratified the risk of AF development with excellent accuracy (AUC 0.76).

CONCLUSIONS

These results indicated that AF is associated with worse prognosis in patients at high risk of HF, and our new risk score may be useful to identify patients at high risk for AF onset.

Distinct risk factors of atrial fibrillation in patients with and without coronary artery disease: a cross-sectional analysis of the BOREAS-CAG Registry data

Objective

Although risk factors of atrial fibrillation (AF) in the general population have been characterised, their impacts on patients with specific diseases are unclear. Our aim was to determine whether risk factors of AF are different in patients with and those without coronary artery disease (CAD).

Methods

We enrolled 1871 consecutive patients who underwent coronary angiography for evaluation of symptoms suggestive of CAD in the BOREAS-CAG Registry between August 2014 and January 2015. After exclusion of patients with valvular heart disease or a history of PCI/cardiac surgery, 1150 patients contributed to multivariate logistic regression analysis to identify risk factors of AF. We also retrieved data for 361 consecutive patients with CAD admitted to Sapporo Medical University Hospital between April 2013 and July 2014 and analysed data for 166 patients using the same inclusion and exclusion criteria as those in the BOREAS-CAG Registry.

Results

Unexpectedly, CAD was independently associated with the absence of AF. The patients were then divided into a non-CAD group (n=576) and a CAD group (n=574) for further analysis. The brain natriuretic peptide level showed a strong association with AF regardless of the presence or absence of CAD. In the non-CAD group, lack of statin use was independently associated with AF, whereas high serum uric acid level was an independent explanatory variable of AF in the CAD group. The association of AF with uric acid was confirmed in a separate group of patients (n=166) enrolled in the CAD cohort in Sapporo Medical University Hospital.

Conclusions

Major risk factors of AF are different in patients with CAD and those without CAD. Patients with CAD are more likely to develop AF when the serum uric acid level is high, whereas no statin administration predicts development of AF in patients without CAD.

Incidence of Atrial Tachyarrhythmias in Patients With Early Repolarization Syndrome

Atrial tachyarrhythmias (ATAs) occur in a significant proportion of Brugada syndrome (BrS) patients and are often an important cause of inappropriate shocks. The aim of this retrospective study was to evaluate the incidence of ATAs and ATA-induced inappropriate shocks in early repolarization syndrome (ERS) patients as compared to BrS patients.We analyzed data from 20 consecutive patients who were diagnosed with ERS and compared them with patients diagnosed with BrS (n = 31). Clinical and ICD interrogation data were collected and analyzed for all events with ICD shocks.Three patients had a history of atrial fibrillation (AF) prior to ICD implantation. One patient had AV reentrant tachycardia and was successfully ablated before ICD implantation. ATAs were newly diagnosed in 4 patients with no prior history of AF. There were no significant differences in gender, age, or left atrial diameter between ATA development. Four (20%) of 20 consecutive patients received inappropriate ICD shocks for ATAs. One suffered from repeat inappropriate shocks triggered by paroxysmal AF and received catheter ablation for AF.ATAs were not infrequent in patients with ERS and seemed to be related to inappropriate ICD therapy. Careful ICD programming is required to reduce ATA-related inappropriate ICD shock in patients with ERS.

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.

Educational inequalities in mortality of patients with atrial fibrillation in Norway

OBJECTIVES

We explored the educational gradient in mortality in atrial fibrillation (AF) patients.

DESIGN

We prospectively followed patients hospitalized with AF as primary discharge diagnosis in the Cardiovascular Disease in Norway 2008-2012 project. The average length of follow-up was 2.4 years. Mortality by educational level was assessed by Cox proportional hazard models. Population attributable fractions (PAF) were calculated. Analyses stratified by age (≤75 and >75 years of age), and adjusted for age, gender, medical intervention, and Charlson Comorbidity Index.

RESULTS

Of 42,138 AF patients, 16% died by end of 2012. Among younger patients, those with low education (≤10 years) had a HR of 2.3 (95% confidence interval 2.0, 2.6) for all-cause mortality relative to those with any college or university education. Similar results were observed for cardiovascular mortality. Disparities in mortality were greater among younger than older patients. A PAF of 35.9% (95% confidence interval 27.9, 43.1) was observed for an educational level of high school/vocational school or less versus higher education in younger patients.

CONCLUSIONS

Increasing educational level associated with better prognosis suggesting underlying education-related behavioral and medical determinants of mortality. A considerable proportion of mortality within 5 years following hospital discharge could be prevented.

Cluster Individuals Based on Phenotype and Determine the Risk for Atrial Fibrillation in the PREVEND and Framingham Heart Study Populations

Background

Risk prediction of atrial fibrillation (AF) is of importance to improve the early diagnosis and treatment of AF. Latent class analysis takes into account the possible existence of classes of individuals each with shared risk factors, and maybe a better method of incorporating the phenotypic heterogeneity underlying AF.

Methods and findings

Two prospective community-based cohort studies from Netherlands and United States were used. Prevention of Renal and Vascular End-stage Disease (PREVEND) study, started in 1997, and the Framingham Heart Study (FHS) Offspring cohort started in 1971, both with 10-years follow-up. The main objective was to determine the risk of AF using a latent class analysis, and compare the discrimination and reclassification performance with traditional regression analysis. Mean age in PREVEND was 49±13 years, 49.8% were men. During follow-up, 250(3%) individuals developed AF. We built a latent class model based on 18 risk factors. A model with 7 distinct classes (ranging from 341 to 1517 individuals) gave the optimum tradeoff between a high statistical model-likelihood and a low number of model parameters. All classes had a specific profile. The incidence of AF varied; class 1 0.0%, class 2 0.3%, class 3 7.5%, class 4 0.2%, class 5 1.3%, class 6 4.2%, class 7 21.7% (p<0.001). The discrimination (C-statistic 0.830 vs. 0.842, delta-C -0.013, p = 0.22) and reclassification (IDI -0.028, p<0.001, NRI -0.090, p = 0.049, and category-less-NRI -0.049, p = 0.495) performance of both models was comparable. The results were successfully replicated in a sample of the FHS study (n = 3162; mean age 58±9 years, 46.3% men).

Conclusions

Latent class analysis to build an AF risk model is feasible. Despite the heterogeneity in number and severity of risk factors between individuals at risk for AF, latent class analysis produces distinguishable groups.

Atrial fibrillation: Therapeutic potential of atrial K+ channel blockers

Despite the epidemiological scale of atrial fibrillation, current treatment strategies are of limited efficacy and safety. Ideally, novel drugs should specifically correct the pathophysiological mechanisms responsible for atrial fibrillation with no other cardiac or extracardiac actions. Atrial-selective drugs are directed toward cellular targets with sufficiently different characteristics in atria and ventricles to modify only atrial function. Several potassium (K⁺) channels with either predominant expression in atria or distinct electrophysiological properties in atria and ventricles can serve as atrial-selective drug targets. These channels include the ultra-rapidly activating, delayed outward-rectifying Kv1.5 channel conducting I_Kur, the acetylcholine-activated inward-rectifying Kir3.1/Kir3.4 channel conducting I_K,ACh, the Ca²⁺-activated K⁺ channels of small conductance (SK) conducting I_SK, and the two pore domain K⁺ (K2P) channels TWIK-1, TASK-1 and TASK-3 that are responsible for voltage-independent background currents I_TWIK-1, I_TASK-1, and I_TASK-3. Here, we briefly review the characteristics of these K⁺ channels and their roles in atrial fibrillation. The antiarrhythmic potential of drugs targeting the described channels is discussed as well as their putative value in treatment of atrial fibrillation.

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.

Update on atrial fibrillation

Atrial fibrillation (AF) is the most common arrhythmia with a substantial effect on individual morbidity and mortality as well as healthcare expenditure. The management of AF is complex and fraught with many uncertain and contentious issues. We have seen substantial progress in AF management in the last two decades including better understanding of the epidemiology, genomics, monitoring, drug and non-pharmacological treatment of the arrhythmia, its complications and stroke risk reduction. In this review, we present a comprehensive discussion on AF with emphasis on most recent updates.

Tailored treatment strategies: a new approach for modern management of atrial fibrillation

Atrial fibrillation (AF) is not benign. Cardiovascular diseases and risk factors differ importantly amongst patients. Careful phenotyping with the aim to start tailored therapy may improve outcome and quality of life. Furthermore, structural remodelling plays an important role in initiation and progression of AF. Therapies that interfere in the remodelling processes are promising because they may modify the atrial substrate. However, success is still limited probably due to variations in the underlying substrate in individual patients. The most favourable effects of lifestyle changes on success of rhythm control have been demonstrated in obese patients with AF. Differences in genotype may also play an important role. Common gene variants have been associated with recurrence of AF after electrical cardioversion, antiarrhythmic drug therapy and catheter ablation. Therefore, both phenotyping and genotyping may become useful for patient selection in the future. Beside the choice of rate or rhythm control, and type of rhythm control, prevention of complications associated with AF may also differ depending on genotype and phenotype. Efficacy of stroke prevention has been well established, but bleeding remains a clinically relevant problem. Risk stratification is still cumbersome, especially in low-risk patients and in those with a high bleeding risk. The decision whether to start anticoagulation (and if so which type of anticoagulant) or, alternatively, to implant an occlusion device of the left atrial appendage may also be improved by genotyping and phenotyping. In this review, we will summarize new insights into the roles of phenotype and genotype in generating more tailored treatment strategies in patients with AF and discuss several patient-tailored treatment options.

The changing circumstance of atrial fibrillation - progress towards precision medicine

The prevalence of atrial fibrillation (AF) in the general population is between 1% and 2% in the developed world and is higher in men than in women. The arrhythmia occurs much more commonly in the elderly, and the estimated lifetime risk of developing AF is one in four for men and women aged 40 years and above. Projected data from multiple population-based studies in the USA and Europe predict a two- to threefold increase in the number of AF patients by 2060. The high lifetime risk of AF and increased longevity underscore the important public health burden posed by this arrhythmia worldwide. AF has multiple aetiologies and a broad variety of presentations. The primary pathologies underlying or promoting the occurrence of AF vary more than for any other cardiac arrhythmia, ranging from autonomic imbalance to organic heart disease and metabolic disorders, such as diabetes mellitus, metabolic syndrome, hyperthyroidism and kidney disease, and lifestyle factors such as smoking, alcohol consumption and participation in endurance sports. Biomarkers are increasingly being investigated and, together with clinical and genetic factors, will eventually lead to a clinically valuable detailed classification of AF which will also incorporate pathophysiological determinants and mechanisms of the arrhythmia. In turn, this will allow the development and application of precision medicine to this troublesome arrhythmia.

No Additional Effect of DPP-4 Inhibitor on Preventing Atrial Fibrosis in Streptozotocin-Induced Diabetic Rat as Compared With Sulfonylurea

Chronic inflammation is known to occur in diabetes mellitus (DM) and contributes to atrial fibrosis, possible substrates for atrial fibrillation. We tested the hypothesis that dipeptidyl peptidase (DPP)-4 inhibitors prevent the formation of atrial fibrosis through their anti-inflammatory activity, beyond the effects of controlling blood glucose.DM models obtained by administration of streptozotocin (STZ) were divided into 3 groups: with PKF275-055, a DPP-4 inhibitor in group D, glibenclamide in group SU, and no additional drug in group P. At 8 weeks after STZ administration, the heart was subjected to Masson trichrome staining and immunohistochemistry with anti-ED2, ED3, and smooth muscle actin antibody.The % area of fibrosis in atria of group P accounted for 14.7% ± 4.1%, showing a significant increase in fibrosis when compared with the control group. In group SU, the % area accounted for 7.9% ± 2.9%, indicating significant deceased fibrosis by sulfonylurea. Meanwhile, we could not find significant differences in group D when compared to group P or group SU. While ED3-positive cells increased in group P (1.12% ± 0.24%), they were significantly decreased in groups D and SU (0.41% ± 0.22% and 0.55% ± 0.29%, respectively). Between group D and SU, however, there were no significant differences in the amount of cells positive to ED2, ED3, and smooth muscle actin antibodies.In STZ-induced DM rats, administration of sulfonylurea and DPP-4 inhibitors inhibited inflammation and fibrosis of the atria. However, no significant differences were observed between the 2 antidiabetic drugs.

Device-identified atrial fibrillation at pacing clinics. Should it guide anticoagulation?

In recent years, there has been a significant increase in the number of devices implanted following improvement in their safety profile, extension of indications and reduction in cost. Although the reason remains largely the beneficial effect on heart rhythm stabilisation, implanted devices might also have additional advantages, notably identification of silent arrhythmia. Should clinicians therefore act on device-identified atrial fibrillation (AF) and should such identification be used to guide anticoagulation management? This review evaluates the current evidence on the management of device-identified asymptomatic AF.

The controversial relationship between exercise and atrial fibrillation: clinical studies and pathophysiological mechanisms

Atrial fibrillation is the most common clinically significant arrhythmia observed both in the general population and in competitive athletes. The most important risk factors are all preventable by regular physical activity. However, although the benefits of moderate physical activity in controlling cardiovascular risk factors and decreasing the risk of atrial fibrillation have been extensively proved, concerns have arisen about the potential negative effects of vigorous exercise, particularly in endurance athletes. Furthermore, in a subset of patients with atrial fibrillation younger than 60 years, routine evaluation does not reveal any cardiovascular disease or any other known causal factor. This condition is called 'lone atrial fibrillation', and the potential mechanisms underlying this condition are speculative and remain to be clarified. Atrial ectopy, increased vagal tone, changes in electrolytes, left atrial dilatation, and fibrosis have been proposed among others as potential mechanisms. However, no convincing data still exist. Particularly, the increase in left atrial size represents in athletes a physiological adaptation to exercise conditioning and the presence of biatrial fibrosis has not been demonstrated in humans. Thus, contrary to patients with cardiovascular disorders, the atrial substrate seems to play a secondary role in healthy athletes. This review article analyzes the controversial relationship between atrial fibrillation and physical activity, with a particular attention on the pathophysiological mechanisms that could be responsible for atrial fibrillation in the athletic population.

Incidence of Atrial Fibrillation and Relationship With Cardiovascular Events, Heart Failure, and Mortality: A Community-Based Study From the Netherlands

BACKGROUND

Important improvements have been made in treatment of diseases associated with atrial fibrillation (AF), such as hypertension, myocardial infarction, and heart failure. Incidence rates and risk factors may have changed with the aging of the population and changing lifestyles. Currently, the risk for AF is only partially explained, possibly because of differences between older cohorts and contemporary populations.

OBJECTIVES

This study investigated the incidence of AF in a contemporary cohort in the Netherlands, together with comorbidities associated with AF and associations of AF with cardiovascular outcomes.

METHODS

Incident AF was ascertained for hospital and study electrocardiograms in 8,265 participants of the PREVEND (Prevention of Renal and Vascular End-Stage Disease) study in Groningen, the Netherlands.

RESULTS

During 9.7 ± 2.3 years of follow-up, 265 participants developed AF, with a resulting overall AF incidence of 3.3 per 1,000 person-years. Advancing age, male sex, antihypertensive drug use, higher body mass index, previous myocardial infarction, and previous stroke were associated with AF. After multivariable adjustment, AF was associated with cardiovascular events (hazard ratio [HR]: 2.24; 95% confidence interval [CI]: 1.06 to 4.75; p = 0.035), heart failure with either reduced or preserved ejection fraction (HR: 4.52; 95% CI: 2.02 to 10.09; p < 0.001), and all-cause mortality (HR: 3.02; 95% CI: 1.73 to 5.27; p < 0.001).

CONCLUSIONS

The incidence of AF in the present cohort was comparable to that shown in data of older studies. Obesity has become a major risk factor for incident AF. Although overall cardiovascular event rates were lower in the present study, the present study confirms the association of incident AF with such events.

Determinants and prognosis of atrial fibrillation in patients with aortic stenosis

Atrial fibrillation (AF) is frequently encountered in patients with aortic stenosis (AS) and its incidence also increases with age. In the general population, AF is known to increase cardiovascular risk. We sought to investigate the prognostic importance of AF associated with AS in the context of routine clinical practice. This analysis was based on 809 patients (75 ± 12 years) diagnosed with AS (aortic valve area <2 cm(2)) and normal (≥50%) ejection fraction (EF). Patients were grouped according to the presence of sinus rhythm (SR) or AF at study enrollment. The AF group comprised 141 patients (17.5%) with AF, whereas 668 patients (82.5%) were in SR at inclusion. Four-year estimates of all-cause mortality with medical and surgical management were 60 ± 5% for the AF group compared with 24 ± 2% for the SR group (p = 0.0001). On multivariate analysis, the risk of all-cause mortality was higher in the AF group than in the SR group (adjusted hazard ratio [HR] 2.47 [1.83 to 3.33], p = 0.0001). AF remained associated with excess mortality risk when the analysis was limited to asymptomatic patients (adjusted HR 2.31 [1.38 to 3.89], p = 0.002) and, respectively, patients with severe AS (adjusted HR 2.22 [1.41 to 3.49], p = 0.001). Among patients managed medically, AF was independently associated with increased risk of death in the overall study population (adjusted HR 2.52 [1.81 to 3.51], p = 0.0001), in asymptomatic AS (adjusted HR 2.12 [1.19 to 3.76], p = 0.01), and in severe AS (adjusted HR 2.23 [1.30 to 3.81], p = 0.004). In conclusion, AF is a major predictor of mortality, in both medically and surgically managed patients with AS, irrespective of the functional status and the severity. AF is, therefore, a strong marker of risk in AS and should be considered for clinical decision making.

Atrial Fibrillation and Non-cardiovascular Diseases: A Systematic Review

Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with an unfavorable prognosis, increasing the risk of stroke and death. Although traditionally associated with cardiovascular diseases, there is increasing evidence of high incidence of AF in patients with highly prevalent noncardiovascular diseases, such as cancer, sepsis, chronic obstructive pulmonary disease, obstructive sleep apnea and chronic kidney disease. Therefore, considerable number of patients has been affected by these comorbidities, leading to an increased risk of adverse outcomes.The authors performed a systematic review of the literature aiming to better elucidate the interaction between these conditions.Several mechanisms seem to contribute to the concomitant presence of AF and noncardiovascular diseases. Comorbidities, advanced age, autonomic dysfunction, electrolyte disturbance and inflammation are common to these conditions and may predispose to AF.The treatment of AF in these patients represents a clinical challenge, especially in terms of antithrombotic therapy, since the scores for stratification of thromboembolic risk, such as the CHADS2 and CHA2DS2VASc scores, and the scores for hemorrhagic risk, like the HAS-BLED score have limitations when applied in these conditions.The evidence in this area is still scarce and further investigations to elucidate aspects like epidemiology, pathogenesis, prevention and treatment of AF in noncardiovascular diseases are still needed.

Atrial fibrillation in patients with diabetes: molecular mechanisms and therapeutic perspectives

Atrial fibrillation (AF) remains the most frequent sustained cardiac arrhythmia worldwide and its incidence increases with ageing, cardiovascular risk factors and comorbidities. Prevalence of diabetes mellitus (DM) is growing fast and is assuming pandemic proportions mostly due to overnutrition and sedentary habits. Experimental and clinical evidences suggest that DM and AF are strongly interconnected. The present review addresses in detail new molecular pathways implicated in the etiology of AF and their relevance for mechanism-based therapeutic strategies in this setting. Advances in risk stratification, drug therapy (i.e., novel anticoagulants) and catheter ablation are also described.

Very Short Paroxysms Account for More Than Half of the Cases of Atrial Fibrillation Detected after Stroke and TIA: A Systematic Review and Meta-Analysis

Background

Guidelines suggest that only poststroke atrial fibrillation episodes lasting 30 s or longer should be considered for anticoagulation. However, little evidence supports this recommendation.

Aims

We performed a systematic review and meta-analysis to investigate the frequency of poststroke atrial fibrillation lasting less than 30 s in stroke and transient ischemic attack patients.

Methods

We searched PubMed, Embase, and Scopus from 1980 to June 30, 2014 for studies reporting the detection of poststroke atrial fibrillation of less than 30 s and of 30 s or longer. The primary endpoint was the proportion of screened patients diagnosed with poststroke atrial fibrillation lasting less than 30 s. The secondary endpoint was the proportion of patients diagnosed with poststroke atrial fibrillation shorter than 30 s among the overall number of patients in whom a poststroke atrial fibrillation was detected after stroke or transient ischemic attack.

Results

From 28 290 titles, we included nine studies in the random-effects meta-analysis. Among stroke and transient ischemic attack patients without a history of atrial fibrillation, 9·0% (95% confidence interval: 4·9–14·3) experienced episodes of poststroke atrial fibrillation shorter than 30 s. An additional 6·5% (95% confidence interval: 3·2–10·9) experienced episodes of poststroke atrial fibrillation longer than 30 s. Among all patients with poststroke atrial fibrillation, 56·3% (95% confidence interval: 37·7–74·0) had poststroke atrial fibrillation episodes shorter than 30 s during diagnostic evaluation. Conclusions The clinical and prognostic significance of poststroke atrial fibrillation episodes shorter than 30 s is unknown. The high frequency of poststroke atrial fibrillation episodes shorter than 30 s justify further investigation into the risk of stroke recurrence and the risk–benefit profile of anticoagulation for this patient population.

Atrial fibrillation and heart failure: cause or effect?

Atrial fibrillation (AF) and heart failure (HF) are two epidemics of the century that have a close and complex relationship. The mechanisms underlying this association remain an area of ongoing intense research. In this review, we will describe the relationship between these two public health concerns, the mechanisms that fuel the development and perpetuation of both, and the evolving concepts that may revolutionize our approach to this dual epidemic.

Atrial fibrillation and gastroesophageal reflux disease: From the cardiologist perspective

We have read with interest the paper by Roman C. and colleagues discussing the relationship between gastroesophageal reflux disease and atrial fibrillation. The review is presenting the available evidence for the common pathogenic mechanisms. However, from a cardiologist perspective, some available data were not highlighted in the review, cardiovascular involvement in gastroesophageal reflux is less assessed. Hypertension, obesity or diabetes mellitus are substrate for left atrial remodeling that initiate and sustained atrial fibrillation development. One of the pathophysiologic mechanisms in atrial fibrillation is the presence of a trigger. Gastroesophageal reflux could be only a trigger for this arrhythmia. We believe that atrial fibrillation should be considered as possible extraesophageal syndrome in the gastroesophageal reflux classification.

Increased prothrombotic profile in the left atrial appendage of atrial fibrillation patients

BACKGROUND

Atrial fibrillation (AF) is associated with an increased risk for thromboembolic events. While observational data demonstrated that the majority of clots are formed within the left atrial appendage, the mechanisms behind this finding remain unclear also due to the fact that vitro studies so far have been hampered by the inability to isolate and culture cells from the atrial appendages.

METHODS

Patients suffering from AF undergoing cardiac surgery were recruited for this study and endocardial cells from their left (LAA) and right atrial appendage (RAA) were isolated and cultured according to a novel established protocol. Once in culture, cells were stimulated with TNF-α (10 ng/mL) and the expression of prothrombotic as well as proinflammatory markers was analyzed.

RESULTS

FACS analysis confirmed a high purity (98%) of isolated LAA endocardial cells. TNF-α significantly increased tissue factor (TF) and PAI-1 expression (n=5; P<0.005), while TFPI remained unchanged. Similarly, expression of VCAM-1 was significantly higher in the LAA as compared to the RAA (n=5; P<0.0001).

CONCLUSION

According to our newly established cell isolation protocol, this study reveals that in patients with AF, the endocardium of the LAA displays an increased prothrombotic and proinflammatory profile as compared to the RAA. This novel observation may constitute an important mechanism to explain the increased propensity of the LAA for clot formation, as well as the predominance of LAA-related thromboembolic complications in AF patients, and may have important implications for the development of novel treatment strategies.

Arrhythmia burden in elderly patients with severe aortic stenosis as determined by continuous electrocardiographic recording: toward a better understanding of arrhythmic events after transcatheter aortic valve replacement

BACKGROUND

This study sought to evaluate the prevalence of previously undiagnosed arrhythmias in candidates for transcatheter aortic valve replacement (TAVR) and to determine the impact on therapy changes and arrhythmic events after the procedure.

METHODS AND RESULTS

A total of 435 candidates for TAVR underwent 24-hour continuous ECG monitoring the day before the procedure. Newly diagnosed arrhythmias were observed in 70 patients (16.1%) before TAVR: paroxysmal atrial fibrillation (AF)/atrial tachycardia (AT) in 28, advanced atrioventricular block or severe bradycardia in 24, nonsustained ventricular tachycardia in 26, and intermittent left bundle-branch block in 3 patients. All arrhythmic events but one were asymptomatic and led to a therapy change in 43% of patients. In patients without known AF/AT, the occurrence of AF/AT during 24-hour ECG recording was associated with a higher rate of 30-day cerebrovascular events (7.1% versus 0.4%; P=0.030). Among the 53 patients with new-onset AF/AT after TAVR, 30.2% had newly diagnosed paroxysmal AF/AT before the procedure. In patients who needed permanent pacemaker implantation after the procedure (n=35), 31.4% had newly diagnosed advanced atrioventricular block or severe bradycardia before TAVR. New-onset persistent left bundle-branch block after TAVR occurred in 37 patients, 8.1% of whom had intermittent left bundle-branch block before the procedure.

CONCLUSIONS

Newly diagnosed arrhythmias were observed in approximately a fifth of TAVR candidates, led to a higher rate of cerebrovascular events, and accounted for a third of arrhythmic events after the procedure. This high arrhythmia burden highlights the importance of an early diagnosis of arrhythmic events in such patients to implement the appropriate therapeutic measures earlier.

Left atrial appendage wall-motion velocity associates with recurrence of nonparoxysmal atrial fibrillation after catheter ablation

Catheter ablation (CA) for nonparoxysmal atrial fibrillation (AF) is controversial due to its high recurrence rate. The aim of this study was to assess retrospectively the diagnostic value of preprocedural left atrial appendage (LAA) wall-motion velocity in predicting recurrence of AF within 1 year after CA. We hypothesized that tissue Doppler-derived measurement of LAA wall-motion velocity associate with recurrence of AF within 1 year after CA. We retrospectively reviewed 47 consecutive patients with nonparoxysmal AF (defined as AF lasting for 1 week or longer) who underwent both transthoracic and transesophageal echocardiography before their first treatment by CA in a single center. Forty-one patients aged 58 ± 10 years were included, and variables predicting the recurrence of AF within 1 year after CA were evaluated. Seventeen patients (41%) developed recurrence of AF within 1 year after CA. Univariate analyses showed that preprocedural LAA upward wall-motion velocity at the apex assessed by transesophageal echocardiography was significantly lower in patients with recurrence of AF than those without recurrence (OR = 1.45, 95% CI: 1.13-2.01, P = 0.009). Multivariate logistic analyses including other potential predictors (duration of AF, left ventricular ejection fraction, E-wave deceleration time, and left atrial wall-motion velocity) identified LAA upward wall-motion velocity at the apex as an independent predictor of outcome. These data suggest in patients with nonparoxysmal AF, preprocedural LAA upward wall-motion velocity at the apex, as determined by tissue Doppler imaging during transesophageal echocardiography, may be a useful indicator for predicting recurrence of AF within 1 year after CA.