American Heart Association atrial fibrillation research summit: a conference report from the American Heart Association

The Critical Roles of Proteostasis and Endoplasmic Reticulum Stress in Atrial Fibrillation

Atrial fibrillation (AF) remains the most common arrhythmia seen clinically. The incidence of AF is increasing due to the aging population. AF is associated with a significant increase in morbidity and mortality, yet current treatment paradigms have proven largely inadequate. Therefore, there is an urgent need to develop new effective therapeutic strategies for AF. The endoplasmic reticulum (ER) in the heart plays critical roles in the regulation of excitation-contraction coupling and cardiac function. Perturbation in the ER homeostasis due to intrinsic and extrinsic factors, such as inflammation, oxidative stress, and ischemia, leads to ER stress that has been linked to multiple conditions including diabetes mellitus, neurodegeneration, cancer, heart disease, and cardiac arrhythmias. Recent studies have documented the critical roles of ER stress in the pathophysiological basis of AF. Using an animal model of chronic pressure overload, we demonstrate a significant increase in ER stress in atrial tissues. Moreover, we demonstrate that treatment with a small molecule inhibitor to inhibit the soluble epoxide hydrolase enzyme in the arachidonic acid metabolism significantly reduces ER stress as well as atrial electrical and structural remodeling. The current review article will attempt to provide a perspective on our recent understandings and current knowledge gaps on the critical roles of proteostasis and ER stress in AF progression.

The relationship between coronary microvascular dysfunction, atrial fibrillation and heart failure with preserved ejection fraction

OBJECTIVE

Coronary microvascular dysfunction (CMD) is a new frontier in cardiovascular disease and an important contributor to myocardial ischemia. A high prevalence of CMD is shown in heart failure, however, the cause-and-effect relationship between CMD and atrial fibrillation (AF) is unknown. We hypothesize that CMD is associated with AF and increases susceptibility to the co-existence of AF and heart failure with preserved ejection fraction (HFpEF).

METHODS

Our study examined the relationship between CMD, AF, and HFpEF in all patients who underwent invasive coronary physiology studies for assessment of chest pain or dyspnea. CMD was defined as impaired coronary flow reserve (CFR) without obstructive coronary disease.

RESULTS

A total of 80 patients (mean age 60±12 years, 68.8% female, median follow up of 2.2 years) were studied. Patients with AF (61%) or HFpEF (62%), or both (71%) were more likely to have CMD than those patients without these conditions. Of the patients with AF and abnormal CFR, 91% had HFpEF. CMD was a predictor of AF with concomitant HFpEF (OR 4.38, P=0.02). Our clinical outcome analysis demonstrated that patients with CMD, AF or HFpEF had lower survival free of HF hospitalization than those patients without (P<0.05). AF (OR 5.5, P=0.02), diabetes, older age, female gender, and higher heart rate were predictors of CMD.

CONCLUSION

CMD is highly prevalent in patients with AF with or without HFpEF. CMD is associated with poor clinical outcomes and the co-existence of AF and HFpEF. Understanding of the association between CMD and AF is important for developing an effective treatment strategy and the risk stratification for the prevention of AF in patients with CMD and vice versa.

Noninvasive biomarker-based risk stratification for development of new onset atrial fibrillation after coronary artery bypass surgery

BACKGROUND

Postoperative atrial fibrillation (PoAF) is a common complication after cardiac surgery. A pre-existing atrial substrate appears to be important in postoperative development of dysrhythmia, but its preoperative estimation is challenging. We tested the hypothesis that a combination of clinical predictors, noninvasive surrogate markers for atrial fibrosis defining abnormal left atrial (LA) mechanics, and biomarkers of collagen turnover is superior to clinical predictors alone in identifying patients at-risk for PoAF.

METHODS

In patients without prior AF undergoing coronary artery bypass grafting, concentrations of biomarkers reflecting collagen synthesis and degradation, extracellular matrix, and regulatory microRNA-29s were determined in serum from preoperative blood samples and correlated to atrial fibrosis extent, alteration in atrial deformation properties determined by 3D speckle-tracking echocardiography, and AF development.

RESULTS

Of 90 patients without prior AF, 34 who developed PoAF were older than non-PoAF patients (72.04 ± 10.7 y; P = 0.043) with no significant difference in baseline comorbidities, LA size, or ventricular function. Global (P = 0.007) and regional longitudinal LA strain and ejection fraction (P = 0.01) were reduced in PoAF vs. non-PoAF patients. Preoperative amino-terminal-procollagen-III-peptide (PIIINP) (103.1 ± 39.7 vs. 35.1 ± 19.3; P = 0.041) and carboxy-terminal-procollagen-I-peptide levels were elevated in PoAF vs. non-PoAF patients with a reduction in miR-29 levels and correlated with atrial fibrosis extent. Combining age as the only significant clinical predictor with PIIINP and miR-29a provided a model that identified PoAF patients with higher predictive accuracy.

CONCLUSIONS

In patients without a previous history of AF, using age and biomarkers of collagen synthesis and regulation, a noninvasive tool was developed to identify those at risk for new-onset PoAF.

A Nurse-led Approach to Improving Cardiac Lifestyle Modification in an Atrial Fibrillation Population

Atrial fibrillation (AF) is a major public health problem and the most common cardiac arrhythmia encountered in clinical practice at this time. AF is associated with numerous symptoms such as palpitations, shortness of breath, and fatigue, which can significantly reduce health-related quality of life and result in serious adverse cardiac outcomes. In light of this, the aim of the present pilot study was to test the feasibility of implementing a mobile health (mHealth) lifestyle intervention titled "Atrial Fibrillation and Cardiac Health: Targeting Improving Outcomes via a Nurse-Led Intervention (ACTION)," with the goal of improving cardiac health measures, AF symptom recognition, and self-management. As part of this study, participants self-identified cardiac health goals at enrollment. The nurse used web-based resources from the American Heart Association (Dallas, TX, USA), which included the Life's Simple 7® My Life Check® assessment, to quantify current lifestyle behavior change needs. Furthermore, on the My AFib Experience™ website (American Heart Association, Dallas, TX, USA), the patient used a symptom tracker tool to capture the date, time, frequency, and type of AF symptoms, and these data were subsequently reviewed by the cardiac nurse. Throughout the six-month intervention period, the cardiac nurse used a motivational interviewing approach to support participants' cardiac health goals. Ultimately, the ACTION intervention was tested in 53 individuals with AF (mean age: 59 ± 11 years; 76% male). Participants were predominantly overweight/obese (79%), had a history of hypertension (62%) or hyperlipidemia (61%), and reported being physically inactive/not preforming any type of regular exercise (52%). The majority (88%) of the participants had one or more Life's Simple 7® measures that could be improved. Most of the participants (98%) liked having a dedicated nurse to work with them on a biweekly basis via the mHealth portal. The most commonly self-reported symptoms were palpitations, fatigue/exercise intolerance, and dyspnea. Seventy percent of the participants had an improvement in their weight and blood pressure as documented within the electronic health record as well as a corresponding improvement in their Life's Simple 7® score at six months. On average, there was a three-pound (1.36-kg) decrease in weight and a 5-mmHg decrease in systolic blood pressure between baseline and at six months. In conclusion, this pilot work provides initial evidence regarding the feasibility of implementing the ACTION intervention and supports testing the ACTION intervention in a larger cohort of AF patients to inform existing AF guidelines and build an evidence base for reducing AF burden through lifestyle modification.

Molecular Mechanism of the Association Between Atrial Fibrillation and Heart Failure Includes Energy Metabolic Dysregulation Due to Mitochondrial Dysfunction

BACKGROUND

Atrial fibrillation (AF) and heart failure (HF) commonly coexist, yet the molecular mechanisms of this association have not been determined. We hypothesized that an energy deficit due to mitochondrial dysfunction plays a significant role in pathogenic link between AF and HF.

METHODS AND RESULTS

Myocardial energy metabolism and mitochondria were examined in atrial tissue samples from patients and mice (cardiac-specific LKB1 knock-out) with HF and/or AF. There was significant atrial energy (ATP) deficit in patients with HF (11.5±1.3 nmol/mg, n=10; vs without HF 17±3.8 nmol/mg, n=5, P = .032). AF was associated with further energy depletion (ATP 5.4±1.2 nmol/mg, n=9) in HF (P = .001) and metabolic stress (AMP/ATP 1.6±0.1 vs 0.7±0.2 in HF alone; P = .043). The left atrium demonstrated lower ATP than the right (P = .004). Mitochondrial dysfunction and remodeling caused ATP depletion with impaired oxidative phosphorylation complexes (succinate dehydrogenase and cytochrome c oxidase), increased reactive oxygen species, and mtDNA damage in mice and human atria with AF and HF.

CONCLUSIONS

Molecular mechanisms of the association between HF and AF include an energy deficit due to mitochondrial dysfunction in atrial myocardium. Mitochondrial functional and structural remodeling in human and mouse atria is associated with energy metabolic dysregulation and oxidative stress that promote AF in HF and vice versa.

Parental Atrial Fibrillation and Stroke or Atrial Fibrillation in Young Adults

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

Preparation for and Implementation of Shared Medical Appointments to Improve Self-Management, Knowledge, and Care Quality Among Patients With Atrial Fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia in adults and is associated with an increased risk of stroke, heart failure, and death. Therapy for this pervasive arrhythmia is complex, involving multiple options that chiefly manage symptoms and prevent stroke. Current therapeutic strategies are also of limited efficacy, and can present potentially life-threatening side effects and/or complications. Emerging research suggests that the burden of AF can be reduced by improving patient understanding of the arrhythmia and teaching patients to adopt and maintain lifestyle and behavior changes. Shared medical appointments (SMAs) have been successfully used to deliver education and develop patient coping and disease management skills for patients with complex needs, but there is a paucity of studies examining the use of SMAs for managing AF. Moreover, few studies have examined strategies for implementing SMAs into routine clinical care. We detail our approach for (1) adapting a patient-centered SMA curriculum; (2) designing an evaluation comparing SMAs to routine care on patient outcomes; and (3) implementing SMAs into routine clinical practice. We conclude that evaluation and implementation of SMAs into routine clinical practice requires considerable planning and continuous engagement from committed key stakeholders, including patients, family members, schedulers, clinical staff, nurse educators, administrators, and billing specialists.

Long-chain n-3 and n-6 polyunsaturated fatty acids and risk of atrial fibrillation: Results from a Danish cohort study

BACKGROUND

Studies of the relation between polyunsaturated fatty acids and risk of atrial fibrillation have been inconclusive. The risk of atrial fibrillation may depend on the interaction between n-3 and n-6 polyunsaturated fatty acids as both types of fatty acids are involved in the regulation of systemic inflammation.

OBJECTIVE

We investigated the association between dietary intake of long chain polyunsaturated fatty acids (individually and in combination) and the risk of atrial fibrillation with focus on potential interaction between the two types of polyunsaturated fatty acids.

DESIGN

The risk of atrial fibrillation in the Diet, Cancer and Health Cohort was analyzed using the pseudo-observation method to explore cumulative risks on an additive scale providing risk differences. Dietary intake of long chain polyunsaturated fatty acids was assessed by food frequency questionnaires. The main analyses were adjusted for the dietary intake of n-3 α-linolenic acid and n-6 linoleic acid to account for endogenous synthesis of long chain polyunsaturated fatty acids. Interaction was assessed as deviation from additivity of absolute association measures (risk differences).

RESULTS

Cumulative risks in 15-year age periods were estimated in three strata of the cohort (N = 54,737). No associations between intake of n-3 or n-6 long chain polyunsaturated fatty acids and atrial fibrillation were found, neither when analyzed separately as primary exposures nor when interaction between n-3 and n-6 long chain polyunsaturated fatty acids was explored.

CONCLUSION

This study suggests no association between intake of long chain polyunsaturated fatty acids and risk of atrial fibrillation.

Influence of Prevalent and Incident Atrial Fibrillation on Post-Trial Major Events in ALLHAT

AIMS

Limited information is available on long-term antihypertensive and lipid-lowering therapy effects on hypertensive patients with atrial fibrillation/flutter (AF/AFL) compared to those without. AF/AFL at baseline or during the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) (mean follow-up 4.9 years) markedly increased risk of stroke, heart failure, CHD, and all-cause mortality. We aimed to determine if AF/AFL continued to impact outcomes during post-trial follow-up (mean 3.8 years).

METHODS

Patients were randomized to chlorthalidone, amlodipine, or lisinopril, and to pravastatin vs. usual care in the lipid-lowering trial (LLT). Of 31,473 available subjects, AF/AFL occurred in 854; 383/14,371 chlorthalidone (2.7%), 247/8565 amlodipine (2.9%), and 224/8537 lisinopril (2.6%). Post-hoc analyses utilized administrative databases for post-trial data. Individuals with AF/AFL were compared to those without during post-trial. Outcomes were analyzed by treatment groups for the antihypertensive and LLT trials.

RESULTS

Among 854 AF/AFL participants, 491 (57.5%) died: 220 in-trial, 271 post-trial. Ten-year all-cause mortality rates for those with in-trial AF/AFL were similar for chlorthalidone and lisinopril, but lower for amlodipine (68, 66, and 49 per 100 persons, respectively); adjusted HR for amlodipine vs. chlorthalidone was 0.68 (95% CI, 0.54-0.87). Ten-year all-cause mortality rates were 57 vs. 65 per 100 persons (pravastatin vs. usual care); non-CVD mortality rates, 18 vs. 39 per 100 persons (pravastatin vs. usual care) (adjusted HR = 0.46, 95% CI, 0.24-0.86).

CONCLUSION

Post-trial follow-up revealed continued deleterious AF/AFL effects. The amlodipine (ALLHAT) and pravastatin (ALLHAT-LLT) treatment groups showed lower all-cause and non-CVD mortality compared to the chlorthalidone and usual-care groups, respectively.

Atrial Arrhythmias and Electroanatomical Remodeling in Patients With Left Ventricular Assist Devices

BACKGROUND

The incidence, predictors, and impact of atrial arrhythmias along with left atrial structural changes in patients with left ventricular assist devices (LVADs) remain undetermined.

METHODS AND RESULTS

All patients who underwent LVAD implantation from 2008 to 2015 at the University of Chicago Medical Center were included. Electronic medical records, electrocardiograms, echocardiograms, and cardiac electrical device interrogations were reviewed. The association of arrhythmias and clinical covariates with survival was evaluated by Kaplan-Meier and Cox proportional hazards analyses. A total of 331 patients were followed for a median of 330 days (range 0-2306 days). Mean age was 57.8±12.8 years, 256 participants (77.3%) were male, mean left ventricular ejection fraction was 20±6.6%, and 124 (37.5%) had ischemic cardiomyopathy. Atrial arrhythmias (53.8%) were highly prevalent and frequently coexisted before LVAD implantation: atrial fibrillation (AF) in 45.9%, atrial flutter in 13.9%, atrial tachycardia in 6.9%, and atrioventricular nodal reentrant tachycardia in 1.2%. New-onset AF was documented in 14 patients (7.8% of patients without prior AF) after the first 30 days with an LVAD. Increasing age, renal insufficiency, and lung disease were predictors of new-onset AF after LVAD implantation. Of patients with paroxysmal AF, 43% had no further AF after LVAD. Left atrial size and volume index improved with LVAD (P<0.005). History of persistent AF, atrial tachycardia, ventricular arrhythmia, coronary artery bypass, and low albumin were associated with decreased survival.

CONCLUSIONS

Atrial arrhythmias are significantly prevalent in patients who require LVAD and are associated with increased mortality; however, LVADs induce favorable atrial structural and electrical remodeling.

Using Phase-Based Costing of Real-World Data to Inform Decision-Analytic Models for Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) poses a significant economic burden. An increasing number of interventions for AF require cost-effectiveness analysis with decision-analytic modeling to demonstrate value. However, high-quality cost estimates of AF that can be used to inform decision-analytic models are lacking.

OBJECTIVES

The objectives of this study were to determine whether phase-based costing methods are feasible and practical for informing decision-analytic models outside of oncology.

METHODS

Patients diagnosed with AF between 1 January 2003 and 30 June 2011 in Ontario, Canada were identified based on a hospital admission for AF using administrative data housed at the Institute for Clinical Evaluative Sciences. Patient observations were then divided into phases based on clinical events typically used for decision-analytic modeling (i.e., minor stroke/transient ischemic attack [TIA], moderate to severe ischemic stroke, myocardial infarction, extracranial hemorrhage [ECH], intracranial hemorrhage [ICH], multiple events, death from an event, or death from other causes). First 30-day and greater than 30-day costs of healthcare resources in each health state were estimated based on a validated methodology. All costs are reported in 2013 Canadian dollars (Can$) and from a healthcare payer perspective.

RESULTS

Patients (n = 109,002) with AF who did not experience a clinical event incurred costs of Can$1566 per 30 days, on average. The average 30-day cost of experiencing a fatal clinical event was Can$42,871, but the cost of dying from all other causes was much smaller (Can$12,800). The clinical events associated with the highest short-term costs were ICH (Can$22,347) and moderate to severe ischemic stroke (Can$19,937). The lowest short-term costs were due to minor ischemic stroke/TIA (Can$12,515) and ECH (Can$12,261). Patients who had experienced a moderate to severe ischemic stroke incurred the highest long-term costs.

CONCLUSIONS

Real-world Canadian data and a phase-based costing approach were used to estimate short- and long-term costs associated with AF-related major clinical events. The results of this study can also inform decision-analytic models for AF.

LKB1 knockout mouse develops spontaneous atrial fibrillation and provides mechanistic insights into human disease process

BACKGROUND

Atrial fibrillation (AF) is a complex disease process, and the molecular mechanisms underlying initiation and progression of the disease are unclear. Consequently, AF has been difficult to model. In this study, we have presented a novel transgenic mouse model of AF that mimics human disease and characterized the mechanisms of atrial electroanatomical remodeling in the genesis of AF.

METHODS AND RESULTS

Cardiac-specific liver kinase B1 (LKB1) knockout (KO) mice were generated, and 47% aged 4 weeks and 95% aged 12 weeks developed spontaneous AF from sinus rhythm by demonstrating paroxysmal and persistent stages of the disease. Electrocardiographic characteristics of sinus rhythm were similar in KO and wild-type mice. Atrioventricular block and atrial flutter were common in KO mice. Heart rate was slower with persistent AF. In parallel with AF, KO mice developed progressive biatrial enlargement with inflammation, heterogeneous fibrosis, and loss of cardiomyocyte population with apoptosis and necrosis. Atrial tissue was infiltrated with inflammatory cells. C-reactive protein, interleukin 6, and tumor necrosis factor α were significantly elevated in serum. KO atria demonstrated elevated reactive oxygen species and decreased AMP-activated protein kinase activity. Cardiomyocyte and myofibrillar ultrastructure were disrupted. Intercellular matrix and gap junction were interrupted. Connexins 40 and 43 were reduced. Persistent AF caused left ventricular dysfunction and heart failure. Survival and exercise capacity were worse in KO mice.

CONCLUSIONS

LKB1 KO mice develop spontaneous AF from sinus rhythm and progress into persistent AF by replicating the human AF disease process. Progressive inflammatory atrial cardiomyopathy is the genesis of AF, through mechanistic electrical and structural remodeling.

Decade-long trends in atrial fibrillation incidence and survival: a community study

BACKGROUND

Contemporary data on temporal trends in incidence and survival after atrial fibrillation are scarce.

METHODS

Residents of Olmsted County, Minn., with a first-ever atrial fibrillation or atrial flutter event between 2000 and 2010 were identified. Age- and sex-adjusted incidence rates were standardized to the 2010 US population, and the relative risk of atrial fibrillation in 2010 versus 2000 was calculated using Poisson regression. Standardized mortality ratios of observed versus expected survival were calculated, and time trends in survival were examined using Cox regression.

RESULTS

We identified 3344 patients with incident atrial fibrillation/atrial flutter events (52% were male, mean age 72.6 years, 95.7% were white). Incidence did not change over time (age- and sex-adjusted rate ratio, 1.01; 95% confidence interval [CI], 0.91-1.13 for 2010 vs 2000). Within the first 90 days, the risk of all-cause mortality was greatly elevated compared with individuals of a similar age and sex distribution in the general population (standardized mortality ratios 19.4 [95% CI, 17.3-21.7] and 4.2 [95% CI, 3.5-5.0] for the first 30 days and 31 to 90 days after diagnosis, respectively). Survival within the first 90 days did not improve over the study period (adjusted hazard ratio, 0.96; 95% CI, 0.71-1.32 for 2010 vs 2000); likewise, no difference in mortality between 2010 and 2000 was observed among 90-day survivors (hazard ratio, 1.05; 95% CI, 0.85-1.31).

CONCLUSIONS

In the community, atrial fibrillation incidence and survival have remained constant over the last decade. A dramatic and persistent excess risk of death was observed in the 90 days after atrial fibrillation diagnosis, underscoring the importance of early risk stratification.

Clinical predictors of risk for atrial fibrillation: implications for diagnosis and monitoring

OBJECTIVE

To create a risk score using clinical factors to determine whom to screen and monitor for atrial fibrillation (AF).

PATIENTS AND METHODS

The AF risk score was developed based on the summed odds ratios (ORs) for AF development of 7 accepted clinical risk factors. The AF risk score is intended to assess the risk of AF similar to how the CHA2DS2-VASc score assesses stroke risk. Seven validated risk factors for AF were used to develop the AF risk score: age, coronary artery disease, diabetes mellitus, sex, heart failure, hypertension, and valvular disease. The AF risk score was tested within a random population sample of the Intermountain Healthcare outpatient database. Outcomes were stratified by AF risk score for OR and Kaplan-Meier analysis.

RESULTS

A total of 100,000 patient records with an index follow-up from January 1, 2002, through December 31, 2007, were selected and followed up for the development of AF through the time of this analysis, May 13, 2013, through September 6, 2013. Mean ± SD follow-up time was 3106±819 days. The ORs of subsequent AF diagnosis of patients with AF risk scores of 1, 2, 3, 4, and 5 or higher were 3.05, 12.9, 22.8, 34.0, and 48.0, respectively. The area under the curve statistic for the AF risk score was 0.812 (95% CI, 0.805-0.820).

CONCLUSION

We developed a simple AF risk score made up of common clinical factors that may be useful to possibly select patients for long-term monitoring for AF detection.

Get With The Guidelines AFIB

Background—

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. It is a cause of stroke, heart failure, and death. Guideline-based treatment can improve outcomes in AF. Unfortunately, adherence to these guidelines is low. Get With The Guidelines is a hospital-based performance initiative, which has been shown to improve adherence over time. Get With The Guidelines-AFIB is a novel quality improvement registry designed to improve adherence to AF guidelines.

Methods and Results—

Hospitals will be recruited by regional American Heart Association staff and key stakeholders. Inpatients or observed patients with AF or atrial flutter will be enrolled. Data collected will include demographic, medical history, and clinical characteristics including laboratory values and treatments. Decision support will guide adherence to achievement and quality measures designed to improve adherence to anticoagulation, heart rate control, safe antiarrhythmic drug use, and patient education and follow-up. Increased adherence to guidelines will be facilitated using rapid-cycle quality improvement, site-specific reporting including national and regional benchmarks and hospital recognition for achievement. Primary analyses will include adherence to American Heart Association/American College of Cardiology performance measures and guidelines. Secondary analyses will include processes of care, risk stratification, treatment of special conditions or populations and use of particular treatment techniques.

Conclusions—

AF is common clinical problem with significant morbidity and mortality. Get With The Guidelines-AFIB is a national hospital-based AF quality improvement program designed to increase adherence to evidence-based guidelines for AF.

Impact of atrial fibrillation and inadequate antithrombotic management on mortality in acute neurovascular syndrome

BACKGROUND

The purpose of this study was to observe adherence to antithrombotic management guidelines among atrial fibrillation (AF) patients and to determine prognostic factors for 3-month mortality in both ischemic and hemorrhagic stroke patients with or without AF.

METHODS

This was a retrospective observational single stroke center cohort study. In 2007, 380 patients with acute stroke-like symptoms were admitted to Tampere University Hospital as candidates for intravenous thrombolysis. Group comparisons (with or without AF) were performed, and binary logistic regression modeling was used to predict 3-month mortality for different clinical and imaging variables.

RESULTS

The prevalence of AF in the acute neurovascular syndrome population was 33%. During hospitalization, the detection rate of previously undiagnosed paroxysmal AF was 8% (17 of 217). Only 26% (18 of 69) of known AF-related ischemic stroke patients had an International Normalized Ratio value above 1.9. National Institutes of Health Stroke Scale score and Alberta Stroke Program Early Computed Tomography Score at admission in ischemic stroke and intracerebral hemorrhage were significant prognostic factors for 3-month mortality in acute neurovascular syndrome patients with AF according to a multivariable analysis. Inadequate antithrombotic management according to at-the-time and current treatment guidelines was not a risk factor for 3-month mortality.

CONCLUSIONS

Patients with AF have more severe stroke and higher mortality than stroke patients without AF. Adherence to the antithrombotic treatment guidelines for the prevention of AF-related cardioembolic strokes is suboptimal. Further studies are needed to evaluate the impact of current antithrombotic treatment guidelines on mortality.

Triage tests for identifying atrial fibrillation in primary care: a diagnostic accuracy study comparing single-lead ECG and modified BP monitors

OBJECTIVE

New electronic devices offer an opportunity within routine primary care settings for improving the detection of atrial fibrillation (AF), which is a common cardiac arrhythmia and a modifiable risk factor for stroke. We aimed to assess the performance of a modified blood pressure (BP) monitor and two single-lead ECG devices, as diagnostic triage tests for the detection of AF.

SETTING

6 General Practices in the UK.

PARTICIPANTS

1000 ambulatory patients aged 75 years and over.

PRIMARY AND SECONDARY OUTCOME MEASURES

Comparative diagnostic accuracy of modified BP monitor and single-lead ECG devices, compared to reference standard of 12-lead ECG, independently interpreted by cardiologists.

RESULTS

A total of 79 participants (7.9%) had AF diagnosed by 12-lead ECG. All three devices had a high sensitivity (93.9-98.7%) and are useful for ruling out AF. WatchBP is a better triage test than Omron autoanalysis because it is more specific-89.7% (95% CI 87.5% to 91.6%) compared to 78.3% (95% CI 73.0% to 82.9%), respectively. This would translate into a lower follow-on ECG rate of 17% to rule in/rule out AF compared to 29.7% with the Omron text message in the study population. The overall specificity of single-lead ECGs analysed by a cardiologist was 94.6% for Omron and 90.1% for Merlin.

CONCLUSIONS

WatchBP performs better as a triage test for identifying AF in primary care than the single-lead ECG monitors as it does not require expertise for interpretation and its diagnostic performance is comparable to single-lead ECG analysis by cardiologists. It could be used opportunistically to screen elderly patients for undiagnosed AF at regular intervals and/or during BP measurement.

Effect of sleep apnea and continuous positive airway pressure on cardiac structure and recurrence of atrial fibrillation

BACKGROUND

Sleep apnea (SA) is associated with an increased risk of atrial fibrillation (AF). We sought to determine the effect of SA on cardiac structure in patients with AF, whether therapy for SA was associated with beneficial cardiac structural remodelling, and whether beneficial cardiac structural remodelling translated into a reduced risk of recurrence of AF after pulmonary venous isolation (PVI).

METHODS AND RESULTS

A consecutive group of 720 patients underwent a cardiac magnetic resonance study before PVI. Patients with SA (n=142, 20%) were more likely to be male, diabetic, and hypertensive and have an increased pulmonary artery pressure, right ventricular volume, atrial dimensions, and left ventricular mass. Treated SA was defined as duration of continuous positive airway pressure therapy of >4 hours per night. Treated SA patients (n=71, 50%) were more likely to have paroxysmal AF, a lower blood pressure, lower ventricular mass, and smaller left atrium. During a follow-up of 42 months, AF recurred in 245 patients. The cumulative incidence of AF recurrence was 51% in patients with SA, 30% in patients without SA, 68% in patients with untreated SA, and 35% in patients with treated SA. In a multivariable model, the presence of SA (hazard ratio 2.79, CI 1.97 to 3.94, P<0.0001) and untreated SA (hazard ratio 1.61, CI 1.35 to 1.92, P<0.0001) were highly associated with AF recurrence.

CONCLUSIONS

Patients with SA have an increased blood pressure, pulmonary artery pressure, right ventricular volume, left atrial size, and left ventricular mass. Therapy with continuous positive airway pressure is associated with lower blood pressure, atrial size, and ventricular mass, and a lower risk of AF recurrence after PVI.

Neighbourhood deprivation and hospitalization for atrial fibrillation in Sweden

AIMS

Several cardiovascular disorders (CVDs) are strongly associated with socioeconomic disparities and neighbourhood deprivation. However, no study has determined whether neighbourhood deprivation is associated with atrial fibrillation (AF). We aimed to determine whether there is an association between neighbourhood deprivation and hospitalization for AF.

METHODS AND RESULTS

The entire Swedish population aged 25-74 years was followed from 1 January 2000 until hospitalization for AF, death, emigration, or the end of the study period (31 December 2008). Data were analysed by multilevel logistic regression, with individual-level characteristics (age, marital status, family income, educational attainment, migration status, urban/rural status, mobility, and comorbidity) at the first level and level of neighbourhood deprivation at the second level. Neighbourhood deprivation was significantly associated with AF hospitalization rate in women [odds ratio (OR) = 1.40, 95% confidence interval (CI) 1.35-1.47], but not men (OR = 1.01, 95% CI 0.97-1.04). The odds of AF in women living in the most deprived neighbourhoods remained significant after adjustment for age and individual-level socioeconomic characteristics (OR = 1.12, 95% 1.08-1.16). However, in the full model, which took account of age, individual-level socioeconomic characteristics, and comorbidities (chronic lower respiratory diseases, OR = 1.30; type 2 diabetes, OR = 1.32; alcoholism and alcohol-related liver disease, OR = 1.57; hypertension, OR = 2.84; obesity, OR = 1.80; heart failure, OR = 7.40; coronary heart disease, OR = 1.81; and hyperthyroidism, OR = 6.79), the odds of AF did not remain significant in women in the most deprived neighbourhoods (OR = 1.03, 95% CI 0.99-1.07).

CONCLUSION

Neighbourhood deprivation and socioeconomic disparities are not independently associated with hospitalized AF in contrast to many other CVDs.

High familial risk of atrial fibrillation/atrial flutter in multiplex families: a nationwide family study in Sweden

BACKGROUND

Although the heritability of atrial fibrillation/atrial flutter (AF/AFl) has been determined, the familial risk in multiplex families is unclear. The main aim of this nationwide study was to determine the familial risk of AF/AFl in multiplex families.

METHODS AND RESULTS

We examined the familial risk of AF/AFl in the entire Swedish population. We linked Multigeneration Register data on individuals aged 0 to 76 years with Hospital Discharge Register data for 1987-2008 and Outpatient Register data for 2001-2008 to compare AF/AFl risk among relatives of all 300 586 individuals with AF/AFl with that among relatives of unaffected individuals. We used conditional logistic regression to investigate differences in exposure between cases and controls. Parents (odds ratio [OR] 1.95 [95% CI 1.89 to 2.00]) and siblings (OR=3.08 [3.00 to 3.16]) of cases had higher odds of AF/AFl than did parents and siblings of controls. AF/AFl ORs were increased in both sexes. For 2% of cases, both parents had AF/AFl, compared with only 0.7% of controls (OR=3.60 [3.30 to 3.92]). Moreover, 3% of cases had ≥2 siblings with AF/AFl, compared with 1% of controls (OR=5.72 [5.28 to 6.19]). In premature cases (diagnosed at age <50 years), the ORs were 5.04 (4.36 to 5.82) and 8.51 (6.49 to 11.15) for AF/AFl in both parents and AF/AFl in ≥2 siblings, respectively. The overall spouse OR was 1.16 (1.13 to 1.19).

CONCLUSIONS

Family history of AF/AFl increases the odds of AF/AFl in first-degree relatives. High familial risks were observed in multiplex families.

Family history as a risk factor for recurrent hospitalization for lone atrial fibrillation: a nationwide family study in Sweden

BACKGROUND

Although the heritability of atrial fibrillation (AF) has been determined, the relevance of family history of AF for the likelihood of recurrent hospitalization for AF is unknown. The aim of this nationwide study was to determine whether family history of AF is a risk factor of recurrent hospitalization for lone AF (LAF), i.e., AF with unknown etiology. The familial risk for first time LAF hospitalization was also determined and compared to the risk of recurrent hospitalization for LAF.

METHODS

We examined whether family history of AF is a risk factor for recurrent hospitalization for LAF in the whole Swedish population. We linked Multigeneration Register data on individuals aged 0-60 years to Hospital Discharge Register data for the period 1987-2009 to compare LAF recurrent hospitalization risk among individuals with and without parental or sibling history of AF. We calculated hazard ratios (HRs) to determine the familial HR of recurrent hospitalization for LAF. Odds ratios (OR) were calculated for familial risk of first time LAF hospitalization.

RESULTS

The risk of recurrent LAF hospitalization was 1.23 (95% CI 1.17-1.30) for individuals with affected parents compared to 1.30 (95% CI 1.22-1.38) for those with affected siblings. After 10 years of follow up 50% of those without and 60% of those with family history had recurrent hospitalization for LAF. The risk of recurrent LAF hospitalization in individuals with two affected parents was 1.65 (95% CI 1.44-1.90). There was an interaction between age and family history, with family history having a weaker effect on LAF hospitalization risk in older age groups. The OR for first time LAF hospitalization was 2.08 (95% CI 2.02-2.15) for offspring with affected parents and 3.23 (95% CI 3.08-3.39) for individuals with affected siblings.

CONCLUSIONS

Family history of AF is a novel risk factor for recurrent LAF hospitalization. The higher recurrence hospitalization risk in multiplex families and younger individuals suggests a genetic contribution. However, the familial risk for recurrent LAF hospitalization was much lower than the risk for first time LAF hospitalization, suggesting that familial and possibly genetic factors are more important for first time LAF hospitalization than recurrent LAF hospitalization.

Aggressive approach and outcome in patients presenting atrial fibrillation and hypertension

AIM

Aggressive approach in patients presenting atrial fibrillation (AF) and hypertension could result in improving rhythm control and reducing admission.

METHODS

Out of 3475 patients presenting AF, those with hypertension (n=1739, 52%) underwent standard (n=591, group 1, years 2004-2005) or aggressive pharmacological and electrical approach (n=1148, group 2, years 2006-2009). Overall, in 1071 patients AF duration was less than 48 h. Primary endpoint was rhythm conversion; secondary endpoints were modalities of rhythm conversion and reduction of admissions.

RESULTS

At univariate and multivariate analyses, AF lasting less than 48 h, absence of comorbidities and younger age were independent predictors of sinus rhythm; conversely, lack of sinus rhythm, older age, AF lasting more than 48 h and comorbidities were independent predictors of hospitalization. Overall, 55% of patients achieved sinus rhythm in group 1 versus 62% in group 2 (p=0.018). Interestingly, in patients with AF lasting less than 48 h, 89% achieved sinus rhythm, more likely by class 1C than by class III antiarrhythmic drugs (p<0.001). Overall reduction of admission accounts for 60%; 50% of patients need admission in group 1 versus 29% in group 2 (p<0.001).

CONCLUSIONS

Aggressive pharmacological and electrical approach in patients presenting AF and hypertension significantly improved rhythm conversion overall up to 62%. Patients with AF lasting less than 48 h eventually achieved sinus rhythm up to 89%, mostly by class IC antiarrhythmic drugs. Admissions eventually reduced up to 60%.