Obesity and outcomes among patients with established atrial fibrillation

Atrial fibrillation: primary prevention, secondary prevention, and prevention of thromboembolic complications: part 1

Atrial fibrillation (AF), is the most common sustained cardiac arrhythmia. It was once thought to be benign as long as the ventricular rate was controlled, however, AF is associated with significant cardiac morbidity and mortality. Increasing life expectancy driven by improved health care and decreased fertility rates has, in most of the world, resulted in the population aged ≥65 years growing more rapidly than the overall population. As the population ages, projections suggest that the burden of AF may increase more than 60% by 2050. Although considerable progress has been made in the treatment and management of AF, primary prevention, secondary prevention, and prevention of thromboembolic complications remain a work in progress. This narrative review was facilitated by a MEDLINE search to identify peer-reviewed clinical trials, randomized controlled trials, meta-analyses, and other clinically relevant studies. The search was limited to English-language reports published between 1950 and 2021. Atrial fibrillation was searched via the terms primary prevention, hyperthyroidism, Wolff-Parkinson-White syndrome, catheter ablation, surgical ablation, hybrid ablation, stroke prevention, anticoagulation, left atrial occlusion and atrial excision. Google and Google scholar as well as bibliographies of identified articles were reviewed for additional references. In these two manuscripts, we discuss the current strategies available to prevent AF, then compare noninvasive and invasive treatment strategies to diminish AF recurrence. In addition, we examine the pharmacological, percutaneous device and surgical approaches to prevent stroke as well as other types of thromboembolic events.

Body Mass Index in Adolescence and Long-Term Risk of Early Incident Atrial Fibrillation and Subsequent Mortality, Heart Failure, and Ischemic Stroke

Background We sought to determine the role of obesity in adolescent men on development of atrial fibrillation (AF) and subsequent associated clinical outcomes in subjects diagnosed with AF. Methods and Results We conducted a nationwide, register-based, cohort study of 1 704 467 men (mean age, 18.3±0.75 years) enrolled in compulsory military service in Sweden from 1969 through 2005. Height and weight, blood pressure, fitness, muscle strength, intelligence quotient, and medical disorders were recorded at baseline. Records obtained from the National Inpatient Registry and the Cause of Death Register were used to determine incidence and clinical outcomes of AF. During a median follow-up of 32 years (interquartile range, 24-41 years), 36 693 cases (mean age at diagnosis, 52.4±10.6 years) of AF were recorded. The multivariable-adjusted hazard ratio (HR) for AF increased from 1.06 (95% CI, 1.03-1.10) in individuals with body mass index (BMI) of 20.0 to <22.5 kg/m² to 3.72 (95% CI, 2.44-5.66) among men with BMI of 40.0 to 50.0 kg/m², compared with those with BMI of 18.5 to <20.0 kg/m². During a median follow-up of ≈6 years in patients diagnosed with AF, we identified 3767 deaths, 3251 cases of incident heart failure, and 921 cases of ischemic stroke. The multivariable-adjusted HRs for all-cause mortality, incident heart failure, and ischemic stroke in AF-diagnosed men with baseline BMI >30 kg/m² compared with those with BMI <20 kg/m² were 2.86 (95% CI, 2.30-3.56), 3.42 (95% CI, 2.50-4.68), and 2.34 (95% CI, 1.52-3.61), respectively. Conclusions Increasing BMI in adolescent men is strongly associated with early AF, and with subsequent worse clinical outcomes in those diagnosed with AF with respect to all-cause mortality, incident heart failure, and ischemic stroke.

Nutrition status, obesity and outcomes in patients with atrial fibrillation

INTRODUCTION AND OBJECTIVES

A paradoxical protective effect of obesity has been previously reported in patients with atrial fibrillation (AF). The aim of this study was to determine the impact of nutritional status and body mass index (BMI) on the prognosis of AF patients.

METHODS

We conducted a retrospective population-based cohort study of patients with AF from 2014 to 2017 from a single health area in Spain. The CONUT score was used to assess nutritional status. Cox regression models were used to estimate the association of BMI and CONUT score with mortality. The association with embolism and bleeding was assessed by a competing risk analysis.

RESULTS

Among 14 849 AF patients, overweight and obesity were observed in 42.6% and 46.0%, respectively, while malnutrition was observed in 34.3%. During a mean follow-up of 4.4 years, 3335 patients died, 984 patients had a stroke or systemic embolism, and 1317 had a major bleeding event. On univariate analysis, BMI was inversely associated with mortality, embolism, and bleeding; however, this association was lost after adjustment by age, sex, comorbidities, and CONUT score (HR for composite endpoint, 0.98; 95%CI, 0.95-1.01; P=.719). Neither obesity nor overweight were predictors of mortality, embolism, and bleeding events. In contrast, nutritional status-assessed by the CONUT score-was associated with mortality, embolism and bleeding after multivariate analysis (HR for composite endpoint, 1.15; 95%CI, 1.14-1.17; P<.001).

CONCLUSIONS

BMI was not an independent predictor of events in patients with AF in contrast to nutritional status, which showed a strong association with mortality, embolism, and bleeding. The study was registered at ClinicalTrials.gov (Identifier: NCT04364516).

The Impact of Obesity on Sudden Cardiac Death Risk

PURPOSE OF REVIEW

We aimed to describe the epidemiology of sudden cardiac death (SCD) in the obese, elaborating on the potential pathophysiological mechanisms linking obesity, SCD, and the outcomes in SCD survivors, as well as looking into the intriguing "obesity paradox" in these patients.

RECENT FINDINGS

Several studies show increased mortality in patients with BMI > 30 kg/m² admitted to the hospital following SCD. At the same time, other studies have implied that the "obesity paradox," described in various cardiovascular conditions, applies to patients admitted after SCD, showing lower mortality in the obese compared to normal weight and underweight patients. We found a significant body of evidence to support that while obesity increases the risk for SCD, the outcomes of obese patients post SCD are better. These findings should not be interpreted as supporting weight gain, as it is always better to prevent the "disaster" from happening than to improve your chances of surviving it. Obesity is shown to be significantly associated with increased risk for SCD; however, there is a growing body of evidence, supporting the "obesity paradox" in the survival of SCD victims. Prospectively, well-designed studies are needed to confirm these findings.

Effectiveness and Safety of Apixaban Versus Warfarin in Obese Patients with Nonvalvular Atrial Fibrillation Enrolled in Medicare and Veteran Affairs

Real-world studies have evaluated the use of anticoagulants in obese patients with nonvalvular atrial fibrillation (NVAF), but they have been limited by sample size or the use of diagnosis codes on claims to define obesity. This retrospective study used body weight data of ≥100 kg or a body mass index of ≥30 kg/m² to identify elderly (aged ≥65 years) NVAF patients with obesity in dually enrolled Veterans Affairs and fee-for-service Medicare patients. It evaluated the risk of stroke/systemic embolism (SE) and major bleeding (MB) in patients that initiated apixaban versus warfarin. Stabilized inverse probability treatment weighting was used to balance the baseline characteristics between patients prescribed apixaban and warfarin in obese patients. Cox models were used to evaluate the relative risk of stroke/SE and MB. Overall, 35.9% (n = 26,522) of the NVAF population were obese, of which 13,604 apixaban and 12,918 warfarin patients were included. After inverse probability treatment weighting, patient characteristics were balanced. The mean age was 75 years, the mean CHA₂DS₂-VASc score (Congestive Heart Failure, Hypertension, Age ≥75 [Doubled], Diabetes Mellitus, Prior Stroke or Transient Ischemic Attack [Doubled], Vascular Disease, Age 65-74, Female) was 3.8, the mean HAS-BLED (Hypertension, Abnormal Renal/Liver Function, Stroke, Bleeding History or Predisposition, Labile INR, Elderly, Drugs/Alcohol Concomitantly) Score was ∼2.6, and >98% of patients were males. Obese apixaban patients were associated with a similar risk of stroke/SE (hazard ratio: 0.82; 95% confidence interval: 0.66 to 1.03) and a significantly lower risk of MB (hazard ratio: 0.62; 95% confidence interval: 0.54 to 0.70) versus warfarin. No significant interaction was observed between treatment and obesity status (nonobese, obese/nonmorbid, obese/morbid) for stroke/SE (interaction p = 0.602) or MB (interaction p = 0.385). In obese patients with NVAF, apixaban was associated with a similar risk of stroke/SE and a significantly lower risk of MB versus warfarin.

Machine Learning Methodologies for Prediction of Rhythm-Control Strategy in Patients Diagnosed With Atrial Fibrillation: Observational, Retrospective, Case-Control Study

Background

The identification of an appropriate rhythm management strategy for patients diagnosed with atrial fibrillation (AF) remains a major challenge for providers. Although clinical trials have identified subgroups of patients in whom a rate- or rhythm-control strategy might be indicated to improve outcomes, the wide range of presentations and risk factors among patients presenting with AF makes such approaches challenging. The strength of electronic health records is the ability to build in logic to guide management decisions, such that the system can automatically identify patients in whom a rhythm-control strategy is more likely and can promote efficient referrals to specialists. However, like any clinical decision support tool, there is a balance between interpretability and accurate prediction.

Objective

This study aims to create an electronic health record–based prediction tool to guide patient referral to specialists for rhythm-control management by comparing different machine learning algorithms.

Methods

We compared machine learning models of increasing complexity and used up to 50,845 variables to predict the rhythm-control strategy in 42,022 patients within the University of Colorado Health system at the time of AF diagnosis. Models were evaluated on the basis of their classification accuracy, defined by the F1 score and other metrics, and interpretability, captured by inspection of the relative importance of each predictor.

Results

We found that age was by far the strongest single predictor of a rhythm-control strategy but that greater accuracy could be achieved with more complex models incorporating neural networks and more predictors for each participant. We determined that the impact of better prediction models was notable primarily in the rate of inappropriate referrals for rhythm-control, in which more complex models provided an average of 20% fewer inappropriate referrals than simpler, more interpretable models.

Conclusions

We conclude that any health care system seeking to incorporate algorithms to guide rhythm management for patients with AF will need to address this trade-off between prediction accuracy and model interpretability.

Effectiveness of Direct Oral Anticoagulants in Obese Adults With Atrial Fibrillation: A Systematic Review of Systematic Reviews and Meta-Analysis

Background: Atrial Fibrillation (AF) is the most common sustained cardiac arrhythmia. Obesity is an independent risk factor for AF. Anticoagulants have been strongly recommended by all international guidelines to prevent stroke. However, altered pathophysiology in obese adults may influence anticoagulant pharmacology. Direct oral anticoagulants (DOACs) in the context of obesity and AF have been examined in recent systematic reviews. Despite the similarities in included studies, their results and conclusions do not agree.

Methods and Results: The protocol for this review was registered with PROSPERO (CRD42020181510). Seven key electronic databases were searched using search terms such as “atrial fibrillation,” “obese,^*” “overweight,” “novel oral anticoagulant,” “direct oral anticoagulant,” “DOAC,” “NOAC,” “apixaban,” dabigatran,” “rivaroxaban,” and “edoxaban” to locate published and unpublished studies. Only systematic reviews with meta-analyses that examined the effect of DOACs in overweight or obese adults with AF, published in the English language, were included. A total of 9,547 articles were initially retrieved. After removing the duplicates, title and abstract review and full-text review, five articles were included in the systematic review. From these only RCTs were included in the meta-analyses. There was disagreement within the published systematic reviews on DOACs in obesity. The results from our meta-analysis did not show any significant difference between all body mass index (BMI) groups for all outcomes at both 12 months and for the entire trial duration. Non-significant differences were seen among the different types of DOACs.

Conclusion: There was no difference between the BMI classes in any of the outcomes assessed. This may be due to the limited number of people in the trial that were in the obese class, especially obese class III. There is a need for large prospective trials to confirm which DOACs are safe and efficacious in the obese class III adults and at which dose.

Predictive Value of HATCH Scoring and Waist-to-Height Ratio in Atrial Fibrillation Following Coronary Artery Bypass Operations Performed with Cardiopulmonary Bypass

Objectives

Postoperative atrial fibrillation (PoAF), an important clinical condition that can occur after coronary artery bypass graft (CABG) operations, may bring about cerebrovascular risks, prolong hospital stay and increase treatment costs. In this prospective study, we aimed to investigate the predictive value of HATCH score and waist/height ratio (WHR) values in revealing the development of PoAF after CABG operations.

Methods

Patients who underwent isolated CABG surgery with cardiopulmonary bypass between May 2019 and November 2019 were prospectively included in the study. Preoperative demographic characteristics, laboratory parameters, and operative parameters of the patients were recorded prospectively.

Results

A total of 255 patients were included in the study. Those who did not develop PoAF were included in Group 1 (N = 196, mean age = 58.9 ± 9.4 years), and those who did were included in Group 2 (n = 59, mean age = 61.1 ± 12 years). There were no statistically significant differences between the two groups in terms of age, gender, presence of hypertension and hyperlipidemia. Rates of chronic obstructive pulmonary disease and previous percutaneous coronary interventions, waist circumference, waist to height ratio and HATCH score values were significantly higher in Group 2 compared to Group 1 ( p values: 0.019, 0.034, 0.001, <0.001, <0.001, respectively). In multivariate analysis, WHR (Odds ratio: 1.068, Confidence interval: 1.032–1.105, p < 0.001) and HATCH score (Odds ratio: 2.590, Confidence interval: 1.850–3.625, p < 0.001) were independent predictors of PoAF.

Conclusions

With this current prospective study, we showed that calculating WHR and HATCH score in the preoperative period can help us predict PoAF.

Atrial fibrillation is associated with cardiovascular events in obese Japanese with one or more cardiovascular risk factors: The Japan Morning Surge Home Blood Pressure (J‐HOP) Study

The impacts of atrial fibrillation (AF) and home blood pressure (BP) on the cardiovascular prognosis of obese individuals have not been clarified. We analyzed the differences in the prognosis (including the effect of the home BP of AF patients with/without obesity) in a Japanese population with cardiovascular risk factors. We enrolled 3,586 patients from the J‐HOP study who had at least one cardiovascular risk factor. We conducted 12‐lead electrocardiography, and the group of AF patients was determined as those whose electrocardiography revealed AF. Obesity was defined as a body mass index >25 kg/m². The primary end points were fatal/nonfatal cardiovascular events (myocardial infarction, stroke, hospitalization for heart failure, and aortic dissection). Among the obese patients, those with AF (n = 36) suffered more significantly cardiovascular events (log rank 7.17, p = .007) compared to the patients with sinus rhythm (n = 1,282), but among the non‐obese patients, the rates of cardiovascular events were similar (log rank 0.006, p = .94) in the AF patients (n = 48) and sinus rhythm patients (n = 2220). After adjusting for age, sex, office/home BP, smoking, diabetes, and creatinine level, AF was an independent predictor of cardiovascular events in the obese group (hazard ratio [HR] 3.05, 95%CI: 1.17‐7.97, p = .023). Home systolic BP was also a predictor of cardiovascular events in the obese group independent of the risk of AF (per 10 mm Hg: HR 1.36, 95%CI: 1.02‐1.83, p = .039). In conclusion, AF was an independent predictor of cardiovascular events in obese patients after adjusting for home BP.

Association between body mass index and stroke severity in acute ischaemic stroke with non-valvular atrial fibrillation

BACKGROUND AND PURPOSE

The objective of this study was to investigate the association between body mass index (BMI) and both initial stroke severity at presentation and functional outcomes after acute ischaemic stroke (AIS) in patients with non-valvular atrial fibrillation (NVAF).

METHODS

Patients were categorized on the basis of their BMI into underweight (BMI <18.5, n = 111), normal (18.5 ≤ BMI <25, n = 1036) and overweight to obese (BMI ≥25, n = 472) groups. Initial stroke severity was assessed using the National Institutes of Health Stroke Scale (NIHSS) score and functional outcomes were assessed using the modified Rankin Scale score at discharge. The differences in stroke severity and functional outcomes were compared between groups using robust log-linear regression with a Poisson distribution and binary logistic regression analysis.

RESULTS

A total of 1619 AIS patients with NVAF from six hospitals were included. Compared with the NIHSS scores [median 5, interquartile range (IQR) 2-14] of normal-weight patients, the NIHSS scores (median 9, IQR 4-19) of underweight patients were more likely to be higher, whereas those of overweight to obese patients were lower (median 4, IQR 1-12) (P < 0.001). In terms of functional outcomes after stroke, underweight patients had a higher risk of poor functional outcomes (odds ratio 1.78, 95% confidence interval 1.09-2.56, P = 0.01) but overweight to obese patients had no significant difference in functional outcomes compared with normal-weight patients.

CONCLUSION

An inverse association was found between BMI and stroke severity in AIS patients with NVAF. This suggests the presence of an obesity paradox for short-term outcomes in patients with NVAF.

Obesity Paradox in Atrial Fibrillation: Implications for Outcomes and Relationship with Oral Anticoagulant Drugs

In the last 40 years, concern about the obesity epidemic has increased. Data from the current literature highlight a strong relationship between obesity and atrial fibrillation (AF), particularly in relation to an increased risk for incident and recurrent AF. A phenomenon called the "obesity paradox" has emerged: the apparently counterintuitive evidence from epidemiological data indicating that overweight and obese patients may have a better prognosis than healthy-weight patients. A differential impact of oral anticoagulants (OACs) in terms of effectiveness and safety in the various body mass index categories has been postulated, particularly in the comparison between non-vitamin-K antagonist oral anticoagulants and vitamin K antagonists. This review aims to summarize the evidence on the impact of obesity in patients with AF, focusing on descriptions of the obesity paradox and its relationships with OAC treatment.

Impact of malnutrition in the embolic–haemorrhagic trade-off of elderly patients with atrial fibrillation

Aims

Nutrition is an important determinant of health above the age of 80 years. Malnutrition in the elderly is often underdiagnosed. The aim of this study was to report the prevalence and prognostic value of malnutrition in patients ≥80 years old with atrial fibrillation (AF) with and without anticoagulant therapy.

Methods and results

We assessed the nutritional status of 4724 octogenarian patients with diagnoses of AF in a single centre from Spain between 2014 and 2017 with the CONUT score. Malnutrition was confirmed in 2036 patients (43.1%). Anticoagulation prescription was more frequent in patients with good nutrition than in those malnourished (79.5% vs. 71.7%, P &lt; 0.001). The impact of malnutrition on mortality was evaluated by Cox regression, whereas its association with ischaemic stroke and major bleeding was studied through competing risk analysis. After multivariate adjusting, malnutrition was associated with mortality [hazard ratio (HR) 1.36, 95% confidence interval (CI) 1.24–1.49], stroke [sub-distribution HR (sHR) 1.37, 95% CI 1.10–1.69], and major bleeding (sHR 1.29, 95% CI 1.02–1.64). In anticoagulated patients, the embolic–haemorrhagic trade-off event was virtually neutral for those who had normal nutritional status [average daily rates (ADRs) for stroke and bleeding: 4.70 and 4.69 per 100 000 patients/day, respectively; difference = +0.01 per 100 000 patients/day; P = 0.99] and negative for those with malnutrition (ADR for stroke and bleeding: 5.38 and 7.61 per 100 000 patients/day, respectively; difference = −2.23 per 100 000 patients/day; P = 0.07).

Conclusion

Malnutrition is very common in octogenarian patients with AF, being a clinical predictor for poor prognosis. For anticoagulated patients, malnutrition was associated with a negative embolic–haemorrhagic balance.

The obesity paradox for outcomes in atrial fibrillation: Evidence from an exposure-effect analysis of prospective studies

The impact of obesity on the prognosis of atrial fibrillation (AF) remains controversial. We conducted an exposure-effect meta-analysis of prospective studies to clarify the relationship between body mass index (BMI) and outcomes in patients with AF. The Cochrane Library, PubMed, and Embase databases were searched through May 1, 2019. Summary relative risks (RRs) were calculated using random-effects models. Nonlinear associations were explored using restricted cubic spline models. Twenty publications involving 161,922 individuals were included. Categorical variable analysis showed that underweight was associated with an increased risk of all-cause mortality (RR: 2.6), cardiovascular death (RR: 2.91), major bleeding (RR: 1.57), stroke or systemic embolism (RR: 1.62), and a composite endpoint (RR: 2.23). In exposure-effect analysis, the risk per 5 BMI increase was reduced for adverse outcomes (RR=0.86, 95% CI: 0.80-0.92 for all-cause death; RR=0.82, 95% CI: 0.71-0.95 for cardiovascular death; RR=0.89, 95% CI: 0.84-0.95 for stroke or systemic embolism; and RR=0.78, 95% CI: 0.67-0.92 for a composite endpoint). There was a significant "U"-shaped exposure-effect relationship with all-cause death, and the nadir of the curve was observed at a BMI of approximately 28. Our results showed that underweight is associated with a worse prognosis, but that overweight and obesity are associated with improved adverse outcomes in patients with AF.

Relation of Obesity to Outcomes of Hospitalizations for Atrial Fibrillation

Obesity has been linked with increased incidence of atrial fibrillation (AF), but impact of presence of obesity on outcomes of hospitalizations for AF has not been investigated. We used the National Inpatient Sample database 2010 to 2014 to identify all adult hospitalizations aged ≥18years with a primary diagnosis of AF. Obese patients were identified using the co-morbidity variable for obesity, as defined in National Inpatient Sample databases. Multivariable logistic regression was used to compare in-hospital outcomes (mortality, acute stroke events) between obese and non-obese patients with AF. Of 431, 734 hospitalizations for AF, 66,138 (15.3%) were obese. Obese patients were younger and more likely to be African-Americans compared with non-obese patients. Despite being younger, obese patients had significantly higher prevalence of cardiovascular co-morbidities such as hypertension, diabetes mellitus, dyslipidemia, smoking, heart failure, and chronic renal failure (p <0.001 for all). After multivariate risk-adjustment, obese patients had a lower observed in-hospital mortality (0.5% vs 1.0%; unadjusted odds ratio = 0.52, 95% confidence interval [CI] 0.46 to 0.58, p <0.001; adjusted odds ratio = 0.83, 95% CI 0.73 to 0.94, p <0.001) and acute stroke events (0.4% vs 0.7%, unadjusted odds ratio = 0. 65, 95% CI 0.57 to 0.73, p < 0.001; adjusted odds ratio = 0.82, 95% CI 0.72 to 0.94) compared with non-obese patients. In conclusion, in this large retrospective analysis of an unselected nationwide cohort of patients hospitalized for AF, obese patients demonstrated lower risk-adjusted odds of in-hospital mortality and stroke events, consistent with an "obesity paradox."

Body mass index and all-cause mortality in patients with atrial fibrillation: insights from the China atrial fibrillation registry study

BACKGROUND

Impact of body mass index (BMI) on all-cause mortality in atrial fibrillation (AF) patients remains controversial.

METHODS

A total of 10,942 AF patients were prospectively enrolled and categorized into four BMI groups: underweight (BMI < 18.5 kg/m²), normal weight (BMI 18.5-24 kg/m²), overweight (BMI 24-28 kg/m²) and obesity (BMI ≥ 28 kg/m²). The primary outcome was all-cause mortality. Different Cox proportional hazards models were performed to evaluate the association between BMI and all-cause mortality.

RESULTS

During a median follow-up of 30 months (IQR 18-48 months), 862 deaths events occurred. Compared to normal BMI, higher BMI was associated with a lower mortality risk (overweight: HR 0.70; 95% CI 0.61-0.81, P < 0.0001 and obesity: HR 0.54; 95% CI 0.44-0.67, P < 0.0001) and lower BMI was associated with a higher mortality risk (HR 2.23, 95% CI 1.67-2.97, P < 0.0001).

CONCLUSION

A reversed relationship between BMI and all-cause mortality in AF patients was found. Higher risk of mortality was observed in underweight patients compared to patients with a normal BMI, while overweight and obese patients had a lower risk of all-cause mortality.

CLINICAL TRIAL REGISTRATION

URL: http://www.chictr.org.cn/showproj.aspx?proj=5831. Unique identifier: ChiCTR-OCH-13003729.

Obesity paradox on outcome in atrial fibrillation maintained even considering the prognostic influence of biomarkers: insights from the ARISTOTLE trial

Objective

We investigated the association between obesity and biomarkers indicating cardiac or renal dysfunction or inflammation and their interaction with obesity and outcomes.

Methods

A total of 14 753 patients in the Apixaban for Reduction In STroke and Other ThromboemboLic Events in Atrial Fibrillation (ARISTOTLE) trial provided plasma samples at randomisation to apixaban or warfarin. Median follow-up was 1.9 years. Body Mass Index (BMI) was measured at baseline and categorised as normal, 18.5–25  kg/m²; overweight, >25 to <30 kg/m²; and obese, ≥30 kg/m². We analysed the biomarkers high-sensitivity C reactive protein (hs-CRP), interleukin 6 (IL-6), growth differentiation factor-15 (GDF-15), troponin T and N-terminal B-type natriuretic peptide (NT-pro-BNP). Outcomes included stroke/systemic embolism (SE), myocardial infarction (MI), composite (stroke/SE, MI, or all-cause mortality), all-cause and cardiac mortality, and major bleeding.

Results

Compared with normal BMI, obese patients had significantly higher levels of hs-CRP and IL-6 and lower levels of GDF-15, troponin T and NT-pro-BNP. In multivariable analyses, higher compared with normal BMI was associated with a lower risk of all-cause mortality (overweight: HR 0.73 (95% CI 0.63 to 0.86); obese: 0.67 (0.56 to 0.80), p<0.0001), cardiac death (overweight: HR 0.74 (95% CI 0.60 to 0.93); obese: 0.71 (0.56 to 0.92), p=0.01) and composite endpoint (overweight: 0.80 (0.70 to 0.92); obese: 0.72 (0.62 to 0.84), p<0.0001).

Conclusions

Regardless of biomarkers indicating inflammation or cardiac or renal dysfunction, obesity was independently associated with an improved survival in anticoagulated patients with AF.

Trial registration number

NCT00412984.

Impact of body mass index on mortality and hospitalisation of patients with atrial fibrillation

BACKGROUND

Atrial fibrillation represents a substantial clinical and public health issue. The definitive impact of body mass index on prognosis of patients with chronic (persistent or permanent) atrial fibrillation remains undetermined.

AIM

The purpose of this study was to investigate the association of body mass index with health outcomes (mortality and re-hospitalisation) of patients with chronic atrial fibrillation.

METHODS

Using data from the Standard versus Atrial Fibrillation spEcific managemenT strategY (SAFETY) trial (a randomised controlled trial of home-based, atrial fibrillation-specific disease management), we performed post-hoc analyses of mortality and re-hospitalisation outcomes during minimum 24-month follow-up according to baseline body mass index profile.

RESULTS

Of 297 participants (mean age 71±11 years, 47% female, mean body mass index 29.6±6.7 kg/m²), 35.0% of participants were overweight (body mass index 25.0-29.9 kg/m²) and 43.1% were obese (body mass index≥30 kg/m²). During follow-up, n=42 died including 16/65 (24.6%) classified as normal body mass index, 16/104 (15.4%) classified as overweight and 10/128 (7.8%) classified as obese. Increasing body mass index was not associated with increased mortality but was associated with re-hospitalisation due to cardiovascular disease with greater length-of-stay (odds ratio 1.05; 95% confidence interval 1.00-1.09, p=0.032). Obese individuals experienced increased unplanned admissions compared to overweight individuals (incidence rate ratio 0.71; 95% confidence interval 0.53-0.96, p=0.028), and increased cardiovascular-related (incidence rate ratio 0.58; 95% confidence interval 0.39-0.86, p=0.007) and all-cause admissions (incidence rate ratio 0.63; 95% confidence interval 0.45-0.89, p=0.008) compared to those classified as normal body mass index.

CONCLUSION

Overweight and obesity were not associated with survival in patients with chronic atrial fibrillation but were associated with more frequent hospital care and prolonged stay.

Risk factors for heart failure hospitalizations among patients with atrial fibrillation

Background

Patients with atrial fibrillation (AF) have an increased risk for the development of heart failure (HF). In this study, we aimed to detect predictors of HF hospitalizations in an unselected AF population.

Methods

The Basel Atrial Fibrillation Cohort Study is an ongoing observational multicenter cohort study in Switzerland. For this analysis, 1193 patients with documented AF underwent clinical examination, venous blood sampling and resting 12-lead ECG at baseline. Questionnaires about lifestyle and medical history were obtained in person at baseline and during yearly follow-up phone calls. HF hospitalizations were validated by two independent physicians. Cox regression analyses were performed using a forward selection strategy.

Results

Overall, 29.8% of all patients were female and mean age was 69 ±12 years. Mean follow-up time was 3.7 ±1.5 years. Hospitalization for HF occurred in 110 patients, corresponding to an incidence of 2.5 events per 100 person years of follow-up. Independent predictors for HF were body mass index (HR 1.40 [95%CI 1.17; 1.66], p = 0.0002), chronic kidney disease (2.27 [1.49; 3.45], p = 0.0001), diabetes mellitus (2.13 [1.41; 3.24], p = 0.0004), QTc interval (1.25 [1.04; 1.49], p = 0.02), brain natriuretic peptide (2.19 [1.73; 2.77], p<0.0001), diastolic blood pressure (0.79 [0.65; 0.96], p = 0.02), history of pulmonary vein isolation or electrical cardioversion (0.54 [0.36; 0.80], p = 0.003) and serum chloride (0.82 [0.70; 0.96], p = 0.02).

Conclusions

In this unselected AF population, several traditional cardiovascular risk factors and arrhythmia interventions predicted HF hospitalizations, providing potential opportunities for the implementation of strategies to reduce HF among AF patients.

Is There an Obesity Paradox for Outcomes in Atrial Fibrillation?

Background and Purpose—

Obesity is a risk factor for all-cause and cardiovascular death but, despite this, an inverse relationship between overweight or obesity and a better cardiovascular prognosis in long-term follow-up studies has been observed; this phenomenon, described as obesity paradox, has also been found evident in atrial fibrillation cohorts.

Methods—

We performed a systematic review on the relationship between body mass index and major adverse outcomes in atrial fibrillation patients. Moreover, we provided a meta-analysis of non–vitamin K antagonist oral anticoagulants (NOACs) trials.

Results—

An obesity paradox was found for cardiovascular death and all-cause death in the subgroup analyses of randomized trial cohorts; however, observational studies fail to show this relationship. From the meta-analysis of NOAC trials, a significant obesity paradox was found, with both overweight and obese patients reporting a lower risk for stroke/systemic embolic event (odds ratio [OR], 0.75; 95% confidence interval [CI], 0.66–0.84 and OR, 0.62; 95% CI, 0.54–0.70, respectively). For major bleeding, only obese patients were at lower risk compared with normal weight patients (OR, 0.84; 95% CI, 0.72–0.98). A significant treatment effect of NOACs was found in normal weight patients, both for stroke/systemic embolic event (OR, 0.66; 95% CI, 0.56–0.78) and for major bleeding (OR, 0.72; 95% CI, 0.54–0.95). Major bleeding risk was lower in overweight patients treated with NOACs (OR, 0.84; 95% CI, 0.71–1.00).

Conclusions—

There may be an obesity paradox in atrial fibrillation patients, particularly for all-cause and cardiovascular death outcomes. An obesity paradox was also evident for stroke/systemic embolic event outcome in NOAC trials, with a treatment effect favoring NOACs over warfarin for both efficacy and safety that was significant only for normal weight patients.

Relation of Body Mass Index With Adverse Outcomes Among Patients With Atrial Fibrillation: A Meta-Analysis and Systematic Review

BACKGROUND

Several studies have investigated the impact of body mass index (BMI) on the prognosis of atrial fibrillation, but the results remain controversial. We sought to estimate the association of BMI with atrial fibrillation-related outcomes.

METHODS AND RESULTS

We systematically searched the Cochrane Library, PubMed, and Elsevier databases for all studies reporting associations between BMI and atrial fibrillation-related outcomes. Relative risks (RRs) and 95% CIs were extracted and pooled. Nine studies with 49 364 participants were included. Underweight BMI was associated with an increased risk of stroke or systemic embolism (RR 1.67, 95% CI 1.12-2.49), all-cause mortaliity (RR 2.61, 95% CI 2.21-3.09), and cardiovascular death (RR 2.49, 95% CI 1.38-4.50). Nevertheless, the pooled RRs of overweight and obese patients were lower than those of normal-weight patients for stroke or systemic embolism (overweight: RR 0.91, 95% CI 0.80-1.04; obese: RR 0.84, 95% CI 0.72-0.98; grade 1 obesity: RR 0.89, 95% CI 0.71-1.11; grade 2 obesity: RR 0.64, 95% CI 0.45-0.91; grade 3 obesity: RR 0.82, 95% CI 0.54-1.25), all-cause death (overweight: RR 0.78, 95% CI 0.62-0.96; obese: RR 0.84, 95% CI 0.64-1.10; grade 1 obesity: RR 0.64, 95% CI 0.57-0.73; grade 2 obesity: RR 0.70, 95% CI 0.47-1.03; grade 3 obesity: RR 0.72, 95% CI 0.59-0.88), and cardiovascular death (overweight: RR 0.79, 95% CI 0.58-1.08; obese: RR 0.99, 95% CI 0.79-1.24).

CONCLUSIONS

Underweight BMI is associated with an increased risk of stroke or systemic embolism, cardiovascular death, and all-cause death in Asian patients with atrial fibrillation, whereas in all atrial fibrillation patients, overweight and obese BMI was not associated with increased risks of these outcomes.

Relationship between smoking and adverse outcomes in patients with atrial fibrillation: A meta-analysis and systematic review

BACKGROUND

Several studies have investigated the impact of smoking on the prognosis of atrial fibrillation (AF), but the results remain controversial. We therefore aimed to estimate the association between smoking and adverse outcomes in patients with AF.

METHODS

We systematically searched the Cochrane Library, PubMed, and Elsevier databases through May 2016 for studies regarding the association between smoking and adverse outcomes in AF patients. Risk ratios [RRs] and 95% confidence intervals [CIs] were abstracted and then pooled using a random-effects model.

RESULTS

A total of 8 cohort studies with 87,373 participants were included in this meta-analysis. Among patients with AF, smoking was associated with increased risks of all-cause death (RR=1.82, 95% CI: 1.33-2.49, P=0.0002) and cardiovascular death (RR=1.54, 95% CI: 1.31-1.81, P<0.00001) but not stroke/thromboembolism (RR=1.19, 95% CI 0.97-1.46; P=0.10). In addition, smoking was associated with an increased risk of major bleeding (RR=1.93, 95% CI 1.08-3.47, P=0.03), even after adjustment for the antithrombotic treatment.

CONCLUSIONS

The published literature demonstrates that smoking is not associated with the risk of stroke/thromboembolism but increases the risks of all-cause death and cardiovascular death in AF patients, as well as the risk of major bleeding in AF patients using anticoagulants.

Impact of Body Mass Index on the Prognosis of Japanese Patients With Non-Valvular Atrial Fibrillation

Obesity is a risk factor for atrial fibrillation (AF); however, obesity is associated with lower mortality in patients with established AF, a phenomenon known as the obesity paradox. Previous studies reported inconsistent results regarding effects of body weight on risk of cardiogenic embolism in patients with AF. To determine relation between body mass index (BMI) and prognosis among Japanese patients with nonvalvular AF (NVAF), a post hoc analysis was conducted using observational data in the J-RHYTHM Registry. Subjects were categorized as underweight (BMI <18.5), normal (18.5 to 24.9), overweight (25.0 to 29.9), or obese (≥30 kg/m(2)). End points included thromboembolism, major hemorrhaging, all-cause mortality, and cardiovascular mortality. Of the 7,406 patients with NVAF, 6,379 patients (70 ± 10 years old; BMI, 23.6 ± 3.9 kg/m(2)) having baseline BMI data constituted the study group. During the 2-year follow-up period, 111 patients had thromboembolism, 124 experienced major hemorrhage, and 159 died. Multivariate analysis with the Cox proportional hazards model showed that none of the BMI categories were independent predictors of thromboembolism. However, being underweight was an independent predictor of all-cause mortality (hazard ratio [HR] 2.45; 95% confidence interval [CI] 1.62 to 3.69; p <0.001) and cardiovascular mortality (HR 3.00, 95% CI 1.52 to 5.91, p = 0.001) when normal weight was used as the reference. Additionally, being overweight was a predictor of lower all-cause mortality (HR 0.60, 95% CI 0.37 to 0.95, p = 0.029). In conclusion, being underweight is associated with higher risks of all-cause and cardiovascular mortality compared with having a normal weight. Being overweight or obese is not associated with increased mortality among Japanese patients with NVAF.

Relation of Nonvalvular Atrial Fibrillation to Body Mass Index (from the SPORTIF Trials)

Obesity is well-established as a major cardiovascular (CV) risk factor. Obesity confers a greater risk for developing atrial fibrillation (AF), but the relation between obesity and established nonvalvular AF for stroke and all-cause death is still unclear. To ascertain the prevalence of overweight and obesity in patients with nonvalvular AF, their influence on adverse events, and the relation with anticoagulation control, we performed this post hoc analysis of the pooled Stroke Prevention using an Oral Thrombin Inhibitor in patients with atrial Fibrillation (SPORTIF) III and V data sets. For this study, we analyzed all patients assigned to the warfarin arm with data on body mass index (BMI). Time in therapeutic range was used as an index of the quality of anticoagulation control. The 3,630 patients eligible for this analysis were categorized as follows: (1) BMI 18.5 to 24.9 ("normal weight") in 24.1%; (2) BMI 25.0 to 29.9 ("overweight") in 39.8%; and BMI ≥30 ("obese") in 36.1%. Both overweight (hazard ratio [HR] 0.70) and obese (HR 0.59) categories were inversely associated with the composite outcome of stroke/all-cause death. A similar inverse association was seen for the end point of stroke (HR 0.61 and 0.47, respectively). Good anticoagulation control also attenuated the association between BMI categories and outcomes. In patients with time in therapeutic range >70%, BMI category was not significantly associated with the composite outcome of stroke/death and stroke. Stroke and all-cause death progressively reduced in overweight and obese anticoagulated patients with AF. The inverse relation of BMI categories to the risk of stroke and all-cause death was mitigated by good anticoagulation control.

Predictors for Stroke and Death in Non-Anticoagulated Asian Patients with Atrial Fibrillation: The Fushimi AF Registry

Background

Atrial fibrillation (AF) increases the risk of stroke and death. Data on the predictors for stroke and death in ‘real-world’ AF patients are limited, especially from large prospective Asian cohorts.

Methods

The Fushimi AF Registry is a community-based prospective survey designed to enroll all AF patients who visited the participating medical institutions in Fushimi-ku, Kyoto, Japan. Follow-up data were available for 3,304 patients (median follow-up period 741 days). We explored the predictors for ‘death, stroke, and systemic embolism (SE)’ during follow-up in 1,541 patients not receiving oral anticoagulants (OAC) at baseline.

Results

The mean age was 73.1 ± 12.5 years, and 673 (44%) patients were female. The mean CHADS₂ and CHA₂DS₂-VASc scores were 1.76 and 3.08, respectively. Cumulative events were as follows: stroke/SE in 61 (4%) and death in 230 (15%), respectively. On multivariate analysis, advanced age (hazard ratio (HR): 1.68, 95% confidence interval (CI): 1.24–2.29), underweight (body mass index <18.5 kg/m²) (HR: 1.71, 95% CI: 1.25–2.32), previous stroke/SE/transient ischemic attack (HR: 1.70, 95% CI: 1.25–2.30), heart failure (HR: 1.59, 95% CI: 1.17–2.15), chronic kidney disease (HR: 1.53, 95% CI: 1.16–2.02), and anemia (HR: 2.41, 95% CI: 1.78–3.28) were independent predictors for death/stroke/SE. Cumulative numbers of these 6 risk predictors could stratify the incidence of death/stroke/SE in patients without OAC, as well as those with OAC in our registry.

Conclusions

Advanced age, underweight, previous stroke/SE/transient ischemic attack, heart failure, chronic kidney disease, and anemia were independently associated with the risk of death/stroke/SE in non-anticoagulated Japanese AF patients.

Review Of Obesity And Atrial Fibrillation: Exploring The Paradox

There is a well established association between obesity and atrial fibrillation (AF). Nevertheless, the effects of obesity in the outcomes of patients with AF has not been investigated since a few years before. In this regard, several studies have demonstrated a better clinical prognosis of AF in overweight and obese populations. In the present manuscrit, we aimed to explore the main articles in which the "obesity paradox in AF" was found.

Exploring The Obesity Paradox In Atrial Fibrillation. AFBAR (Atrial Fibrillation Barbanza Area) Registry Results

INTRODUCTION AND OBJECTIVES

Previous studies have described an inverse relationship between obesity and adverse events in a variety of conditions. Our aim was to investigate the relationship between obesity and prognosis in patients with atrial fibrillation.

METHODS

We studied 746 patients who were prospectively included, between January and April 2008, in the AFBAR (Atrial Fibrillation in BARbanza area) registry. Patients were categorized into 3 body mass index groups using baseline measurements: normal (< 25 kg/m2), overweight (25-30 kg/m2), and obese (≥30 kg/m2). Survival free from the composite endpoint hospitalization for cardiovascular causes or all-cause mortality was compared across the 3 body mass index groups. A multivariable Cox proportional hazard regression was also performed to determine the independent effect of obesity as well as overweight, with respect to normal body mass index as a reference category, regarding the study endpoint. Median follow-up time was 36 (28-36) months.

RESULTS

49.3% were obese and 38.2% had overweight. The composite endpoint rate was 70.9%, 67.5%, and 57.6% for obese, overweight, and normal weight patients, respectively (log rank test; p=0.02). An inverse association of obesity with a favorable prognosis persisted even after multivariable adjustment: hazard ratio 0.668; 95% confidence interval 0.449-0.995; p=0.047. Hazard ratio of overweight, however, was 0.741; 95% confidence interval: 0.500-1.098; p=0.096.

CONCLUSIONS

Obesity, defined as a body mass index ≥ 30 kg/m2, is associated with better prognosis in a community-based cohort of patients with atrial fibrillation.

Plasma asymmetric dimethylarginine and adverse events in patients with atrial fibrillation referred for coronary angiogram

OBJECTIVES

Elevated plasma levels of asymmetric dimethylarginine (ADMA) have been reported to be associated with endothelial dysfunction, inflammation, and oxidative stress in multiple cardiovascular diseases. This study aimed to investigate whether ADMA was a predictor of clinical outcomes in atrial fibrillation (AF).

METHODS AND RESULTS

From 2006-2009, 990 individuals were referred to our institution for coronary angiography. Among these patients, 141 subjects with a diagnosis of AF, including 52 paroxysmal AF (PAF) and 89 non-paroxysmal AF (non-PAF) patients, were identified as the study population. Plasma ADMA levels were measured. An adverse event was defined as the occurrence of ischemic stroke or cardiovascular death. The ADMA levels were higher in AF than non-AF patients (0.50 ± 0.13 versus 0.45 ± 0.07 µmol/L; p<0.001). Besides, non-PAF patients had higher ADMA levels than PAF patients (0.52 ± 0.15 versus 0.48 ± 0.08 µmol/L; p<0.001). During the follow-up of 30.7±14.4 months, 21 patients (14.9%) experienced adverse events, including cardiovascular death in 7 patients and ischemic stroke in 14. ADMA level, CHA2DS2-VASc score, and left atrial diameter were independent predictors of adverse events in the multivariate analysis. At a cutoff-value of 0.55 µmol/L, the Kaplan-Meier survival analysis showed that patients with a high ADMA level had a higher event rate during the follow-up period.

CONCLUSIONS

A higher level of ADMA was a risk factor of adverse events in AF patients, which was independent from the CHA2DS2-VASc score. It deserves to further study whether ADMA could potentially refine the clinical risk stratification in AF.

Body mass index and adverse events in patients with incident atrial fibrillation

BACKGROUND

Obesity is associated with the development of atrial fibrillation and may impact atrial fibrillation-related outcomes. To date, no anthropometric measure is included in any risk stratification scheme for stroke and death in atrial fibrillation patients.

METHODS

The prospective Danish Diet, Cancer and Health study is a cohort including 57,053 participants (27,178 men and 29,875 women) aged between 50 and 64 years. The study population for this study included the 3135 patients (2025 men and 1110 women) who developed incident atrial fibrillation during follow-up.

RESULTS

Of the subjects with atrial fibrillation, 1414 (45%) had a body mass index (BMI) in the overweight category (BMI 25 to <30 kg/m(2)) and 767 (24%) were categorized as obese (BMI ≥30 kg/m(2)). During a median follow-up of 4.9 years, 609 deaths and 216 thromboembolic events (98% ischemic strokes) occurred. Using normal-weight patients as reference, the risk of a composite end point of "ischemic stroke, thromboembolism, or death" was significantly higher in overweight (crude hazard ratio [HR] 1.31; 95% confidence interval [CI], 1.09-1.56) and obese patients (crude HR 1.55; 95% CI 1.27-1.90). After adjustment for CHADS2 and CHA2DS2-VASc scores, the HRs for the composite end point were 1.21 (95% CI 1.02-1.45) and 1.31 (95% CI 1.10-1.56), respectively, for overweight and 1.25 (95% CI 1.03-1.53) and 1.36 (95% CI 1.11-1.65), respectively, for obese. Continuous analyses of BMI stratified by sex identified obese men and normal-weight women as the sex-specific "high-risk" categories.

CONCLUSION

Overweight and obesity are risk factors for "ischemic stroke, thromboembolism or death" in patients with atrial fibrillation, even after adjustment for CHADS2 and CHA2DS2-VASc scores. The association between BMI and outcomes among atrial fibrillation patients may be modified by sex.

Impact of Metabolic Syndrome on Ablation-Outcome in Patients with Atrial Fibrillation: A Systematic Review

Metabolic syndrome (MS), a pro-inflammatory state with hypertension, diabetes, dyslipidemia and obesity is presumed to be a close associate of atrial fibrillation (AF). However, the exact mechanism by which MS facilitates perpetuation of AF is yet to be fully understood. Moreover, the impact of the components of MS as well as MS as a group, on ablation-outcome in AF is not clearly elucidated until now. This review has compiled the results from major studies that have looked into those risk factors and defined their significance in influencing ablation-outcome in AF. It has also overviewed the impact of life-style changes that might improve the success rate of AF-ablation by effectively addressing the different constituents of MS.

Association of body mass index, diabetes, hypertension, and blood pressure levels with risk of permanent atrial fibrillation

BACKGROUND

After an initial episode of atrial fibrillation (AF), AF may recur and become permanent. AF progression is associated with higher morbidity and mortality. Understanding the risk factors for permanent AF could help identify people who would benefit most from interventions.

OBJECTIVE

To determine whether body mass index (BMI), diabetes, hypertension, and blood pressure levels are associated with permanent AF among people whose initial AF episode terminated.

DESIGN

Population-based inception cohort study.

PARTICIPANTS

Enrollees in Group Health, an integrated health care system, aged 30-84 with newly diagnosed AF in 2001-2004, whose initial AF terminated within 6 months and who had at least 6 months of subsequent follow-up (N = 1,385).

MAIN MEASURES

Clinical characteristics were determined from medical records. Permanent AF was determined from medical records and ECG and administrative databases. Permanent AF was defined as AF present on two separate occasions 6-36 months apart, without any documented sinus rhythm between the two occasions. Cox proportional hazards models were used to estimate adjusted hazard ratios (HRs).

KEY RESULTS

Five-year cumulative incidence of permanent AF was 24 %. Compared with normal BMI (18.5-24.9 kg/m(2)), BMI levels of 25.0-29.9 (overweight), 30.0-34.9 (obese 1), 35.0-39.9 (obese 2), and ≥ 40.0 kg/m(2) (obese 3) were associated with HRs of permanent AF of 1.26 (95 % CI: 0.92, 1.72); 1.35 (0.96, 1.91); 1.50 (0.97, 2.33); and 1.79 (1.13, 2.84), adjusted for age, sex, diabetes, hypertension, blood pressure, coronary heart disease, valvular heart disease, heart failure, and prior stroke. Diabetes, hypertension, and blood pressure were not associated with permanent AF.

CONCLUSIONS

For people whose initial AF episode terminates, benefits of having lower BMI may include a lower risk of permanent AF. Risk of permanent AF was similar for people with and without diabetes or hypertension and across blood pressure levels.

Atrial Fibrillation Ablation in Obese Patients

Despite the increased burden of atrial fibrillation (AF), obese patients have similar, if not slightly improved, mortality, described as the "obesity paradox." Catheter ablation for AF in obese patients is a reasonable option, but patients should be screened for sleep apnea and counseled about the possibility of longer procedure times and repeat procedures to achieve similar success rates. Quality of life will likely improve after successful ablation. Although no statistically significant increases in procedural complications have occurred in obese subjects, patients should be counseled about the increased radiation dose and higher incidence of left atrial thrombus preablation.

Relation of obesity to recurrence rate and burden of atrial fibrillation

Obesity is associated with new-onset atrial fibrillation (AF). However, the effect of obesity on AF recurrence or burden has not been studied. The aim of this study was to investigate the relation between AF recurrence, AF burden, and body mass index (BMI). A limited-access data set from the Atrial Fibrillation Follow-Up Investigation of Rhythm Management (AFFIRM) trial provided by the National Heart, Lung, and Blood Institute was used. Statistical analysis was done with a generalized linear mixed model. In 2,518 patients who had BMIs recorded, higher BMI was associated with a higher number of cardioversions (odds ratio [OR] 1.017, 95% confidence interval [CI] 1.005 to 1.029 for a BMI increase of 1 kg/m(2); OR 1.088, 95% CI 1.024 to 1.155 for a BMI increase of 5 kg/m(2); OR 1.183, 95% CI 1.049 to 1.334 for a BMI increase of 10 kg/m(2); p = 0.006 for each). Increased BMI was also associated with a higher likelihood of being in AF on follow-up (OR 1.020, 95% CI 1.002 to 1.038 per 1 kg/m(2) increased BMI, p = 0.0283; OR 1.104, 95% CI 1.011 to 1.205 per 5 kg/m(2) increased BMI, p = 0.0283; OR 1.218, 95% CI 1.021 to 1.452 per 10 kg/m(2) increased BMI, p = 0.0283). In a multivariate analysis, left atrial size but not BMI was an independent predictor of AF recurrence and AF burden. Because left atrial size was correlated with BMI, the effect of BMI on AF can be likely explained by greater left atrial size in subjects with higher BMIs. In conclusion, obesity is associated with a higher incidence of recurrence of AF and greater AF burden.