Nicholas Antic

IMPORTANCE: Obesity is a risk factor for atrial fibrillation. Whether weight reduction and cardiometabolic risk factor management can reduce the burden of atrial fibrillation is not known. OBJECTIVE: To determine the effect of weight reduction and management of cardiometabolic risk factors on atrial fibrillation burden and cardiac structure. DESIGN, SETTING, AND PATIENTS: Single-center, partially blinded, randomized controlled study conducted between June 2010 and December 2011 in Adelaide, Australia, among overweight and obese ambulatory patients (N = 150) with symptomatic atrial fibrillation. Patients underwent a median of 15 months of follow-up. INTERVENTIONS: Patients were randomized to weight management (intervention) or general lifestyle advice (control). Both groups underwent intensive management of cardiometabolic risk factors. MAIN OUTCOMES AND MEASURES: The primary outcomes were Atrial Fibrillation Severity Scale scores: symptom burden and symptom severity. Scores were measured every 3 months from baseline to 15 months. Secondary outcomes performed at baseline and 12 months were total atrial fibrillation episodes and cumulative duration measured by 7-day Holter, echocardiographic left atrial area, and interventricular septal thickness. RESULTS: Of 248 patients screened, 150 were randomized (75 per group) and underwent follow-up. The intervention group showed a significantly greater reduction, compared with the control group, in weight (14.3 and 3.6 kg, respectively; P < .001) and in atrial fibrillation symptom burden scores (11.8 and 2.6 points, P < .001), symptom severity scores (8.4 and 1.7 points, P < .001), number of episodes (2.5 and no change, P = .01), and cumulative duration (692-minute decline and 419-minute increase, P = .002). Additionally, there was a reduction in interventricular septal thickness in the intervention and control groups (1.1 and 0.6 mm, P = .02) and left atrial area (3.5 and 1.9 cm2, P = .02). CONCLUSIONS AND RELEVANCE: In this study, weight reduction with intensive risk factor management resulted in a reduction in atrial fibrillation symptom burden and severity and in beneficial cardiac remodeling. These findings support therapy directed at weight and risk factors in the management of atrial fibrillation. TRIAL REGISTRATION: anzctr.org.au Identifier: ACTRN12610000497000.

Intensive research over the last few decades has seen significant advances in our understanding of the complex mechanisms underlying atrial fibrillation (AF). The epidemic of AF and related hospitalizations has been described as a 'rising tide' with estimates of the global AF burden showing no sign of retreat. There is urgency for effective translational programs in this field to facilitate more individualized and targeted therapy to modify the abnormal atrial substrate responsible for the perpetuation of this arrhythmia. In this review, we chose to focus on several novel aspects of AF pathogenesis whereby practical applications in clinical practice are currently available or potentially not too far away. Specifically, we explored the contribution of atrial fibrosis, epicardial adipose tissue, autonomic nervous system, hyper-coagulability, and focal drivers to adverse atrial remodelling and AF persistence. We also highlighted the potential practical means of monitoring and targeting these factors to achieve better outcomes in patients suffering from this debilitating illness. Emerging data also support a new paradigm for targeting AF substrate with aggressive risk factor management. Finally, multi-disciplinary integrated care approach has shown great promise in improving cardiovascular outcomes of patients with AF along with potential cost savings.

STUDY OBJECTIVES: Poor adherence to continuous positive airway pressure (CPAP) commonly affects therapeutic response in obstructive sleep apnea (OSA). We aimed to determine predictors of adherence to CPAP among participants of the Sleep Apnea and cardioVascular Endpoints (SAVE) trial. METHODS: SAVE was an international, randomized, open trial of CPAP plus usual care versus usual care (UC) alone in participants (45-75 years) with co-occurring moderate-to-severe OSA (≥12 episodes/h of ≥4% oxygen desaturation) and established cardiovascular (CV) disease. Baseline sociodemographic, health and lifestyle factors, OSA symptoms, and 1-month change in daytime sleepiness, as well as CPAP side effects and adherence (during sham screening, titration week, and in the first month), were entered in univariate linear regression analyses to identify predictors of CPAP adherence at 24 months. Variables with p <0.2 were assessed for inclusion in a multivariate linear mixed model with country, age, and sex included a priori and site as a random effect. RESULTS: Significant univariate predictors of adherence at 24 months in 1,121 participants included: early adherence measures, improvement in daytime sleepiness at 1 month, fixed CPAP pressure, some measures of OSA severity, cardiovascular disease history, breathing pauses, and very loud snoring. While observed adherence varied between countries, adherence during sham screening, initial titration, and the first month of treatment retained independent predictive value in the multivariate model along with fixed CPAP pressure and very loud snoring. CONCLUSIONS: Early CPAP adherence had the greatest predictive value for identifying those at highest risk of non-adherence to long-term CPAP therapy. CLINICAL TRIAL REGISTRATION: SAVE is registered with clinicaltrials.gov (NCT00738179).