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Although previous studies have demonstrated a U-shaped relationship between alcohol and sudden cardiac death (SCD), there is a paucity of evidence on the role of alcohol specifically on incident ventricular arrhythmias (VAs).The purpose of this study was to characterize associations of total and beverage-specific alcohol consumption with incident VA and SCD using data from the UK Biobank.Alcohol consumption reported at baseline was calculated as UK standard drinks (8 g of alcohol) per week. Outcomes were assessed through hospitalization and death records. Alcohol consumption was modeled as restricted cubic splines in multivariate Cox regression models and corrected for regression dilution bias.We studied 408,712 middle-aged individuals (52.1% female) over a median follow-up time of 11.5 years. A total of 1733 incident VA events and 2044 SCDs occurred. For incident VA, no clear association was seen with total alcohol consumption. Although consumption of greater amounts of spirits was associated with increased VA risk, no other significant beverage-specific associations were observed. For SCD, a U-shaped association was seen for total alcohol consumption, such that consumption of26 drinks per week was associated with lowest risk. Consumption of greater amounts of beer, cider, and spirits was potentially associated with increasing SCD risk, whereas increasing red and white wine intake was associated with reduced risk.In this predominantly white cohort, no association of total alcohol consumption was observed with VA, whereas a U-shaped association was present for SCD. Additional studies utilizing accurately defined VA and SCD events are required to provide further insights into these contrasting findings.

Objective To examine the potential association of atrial fibrillation (AF) to syncope and falls, we undertook a systematic review and meta-analysis given the increasing prevalence of AF in older adults as well as emerging data that it is a risk factor for dementia. Patients and Methods CENTRAL, PubMed, and EMBASE databases were searched from inception to January 31, 2019, to retrieve relevant studies. Search terms consisted of MeSH, tree headings, and keywords relating patients with "AF," "falls," "syncope," and "postural hypotension." When possible; results were pooled using a random-effects model. Results A total of 10 studies were included, with 7 studies (36,444 patients; mean ± SD age, 72±10 years) reporting an association between AF and falls and 3 studies (6769 patients; mean ± SD age, 65±3 years) reporting an association between AF and syncope. Pooled analyses demonstrate that AF is independently associated with falls (odds ratio, 1.19; 95% CI, 1.07-1.33; P=.001) and syncope (odds ratio, 1.88; 95% CI, 1.20-2.94; P=.006). There was overall moderate bias and low-moderate heterogeneity (I2=37%; P=.11) for falls and moderate bias with low statistical heterogeneity (I2=0%; P=.44) for syncope. Persistent AF, but not paroxysmal AF, was associated with orthostatic intolerance in 1 study (4408 patients; mean ± SD age, 66±6 years). Conclusion AF is independently associated with syncope and falls in older adults. Further studies are needed to delineate mechanistic links and to guide management to improve outcomes in these patients. Trial Registration PROSPERO: trial identifier: CRD4201810721.

Atrial fibrillation (AF) management guidelines recommend screening for symptoms of sleep-disordered breathing (SDB). We aimed to assess the role of self-reported daytime sleepiness in detection of patients with SDB and AF.A total of 442 consecutive ambulatory patients with AF who were considered candidates for rhythm control and underwent polysomnography comprised the study population. The utility of daytime sleepiness (quantified by the Epworth Sleepiness Scale [ESS]) to predict any (apnea-hypopnea index [AHI] ≥ 5), moderate-to-severe (AHI ≥ 15), and severe (AHI ≥ 30) SDB on polysomnography was tested.Mean age was 60 ± 11 years and 69% patients were men. SDB was present in two-thirds of the population with 33% having moderate-to-severe SDB. Daytime sleepiness was low (median ESS = 8/24) and the ESS poorly predicted SDB, regardless of the degree of SDB tested (area under the curve: 0.48-0.56). Excessive daytime sleepiness (ESS ≥ 11) was present in 11.9% of the SDB population and had a negative predictive value of 43.1% and a positive predictive value of 67.5% to detect moderate-to-severe SDB. Male gender (odds ratio [OR]: 2.3, 95% confidence interval [CI]: 1.4-3.8, P = 0.001), obesity (OR: 3.5, 95% CI: 2.3-5.5, P0.001), diabetes (OR: 2.3, 95% CI: 1.2-4.4, P = 0.08), and stroke (OR: 4.6, 95% CI: 1.7-12.3, P = 0.002) were independently associated with an increased likelihood of moderate-to-severe SDB.In an ambulatory AF population, SDB was common but most patients reported low daytime sleepiness levels. Clinical features, rather than daytime sleepiness, were predictive of patients with moderate-to-severe SDB. Lack of excessive daytime sleepiness should not preclude patients from being investigated for the potential presence of concomitant SDB.

Objectives This study sought to determine night-to-night variability in the severity of sleep-disordered breathing (SDB) and the dynamic intraindividual relationship to daily risk of incident atrial fibrillation (AF) by using simultaneous long-term day-by-day SDB and AF monitoring. Background Night-to-night variability in SDB severity may result in a dynamic exposure to SDB related conditions impacting the timing and extent of cardiovascular responses. Methods This study was an observational cohort study. Daily data for AF burden and average respiratory disturbance index (RDI) were extracted from pacemakers capable of monitoring nightly SDB and daily AF burden in 72 patients. Nightly RDI values were grouped into quartiles of severity within each patient. AF burdens of >5 min, >1 h, and >12 h were the outcome variables. Results A total of 32% of patients had a mean RDI of ≥20/h, indicative of overall severe SDB. There was significant night-to-night variation in RDI reflected by an absolute SD of ±6.3 events/h (range 2 to 14 events/h) within any given patient. Within each patient, the nights with the highest RDI (in their highest quartile) conferred a 1.7-fold (1.2 to 2.2; p Conclusions There is considerable night-to-night variability in SDB severity which cannot be detected by 1 single overnight sleep study. SDB burden may be a better metric with which to assess the extent of dynamic SDB related cardiovascular responses such as daily AF risk than the categorical diagnosis of SDB. (Night-to-Night Variability in Severity of Sleep Apnea and Daily Dynamic Atrial Fibrillation Risk [VARIOSA-AF]; ACTRN 12618000757213)

Background Sleep-disordered breathing (SDB) is highly prevalent in patients with atrial fibrillation (AF) and its treatment can improve rhythm control. Polysomnography (PSG) is the gold standard for the diagnosis of SDB but its high cost and limited availability constrain its role as a standard SDB screening tool. We sought to assess the diagnostic utility of overnight oximetry in predicting SDB in AF patients. Methods We analyzed prospectively collected data on 439 patients with documented AF (62% paroxysmal AF) who underwent PSG. Overnight oximetry was used to determine the oxygen desaturation index (ODI, number of desaturation/h) by a novel automated computer algorithm. ODI was validated against PSG derived apnea-hypopnea index (AHI). Results The sample consisted of 69% men with a mean age of 59.9 ± 11.3 years and body mass index of 30 ± 5 kg/m2. The median AHI was 9.5 [3.6–21.0]/h and the prevalence of moderate (AHI 15–29/h) and severe SDB (AHI ≥ 30/h) was 17.3% and 16.6% respectively. The ODI was able to detect moderate-to-severe SDB (AHI ≥ 15/h; area under the receiver-operating-characteristic curve (AUC): 0.951, 95% CI: 0.929–0.972) and severe SDB (AHI ≥ 30/h; 0.932, 95% CI: 0.895–0.968) with high diagnostic accuracy. An ODI cut-off of 4.1/h resulted in a 91% sensitivity and 83% specificity in discriminating between patients with and without AHI ≥ 15/h. An ODI of 7.6/h yielded a sensitivity and specificity for AHI ≥ 30/h of 89% and 83%, respectively. Conclusions ODI derived from a simple and low-cost overnight oximetry can be used as an accessible and reliable screening tool, particularly to rule out SDB.

Regular exercise contributes to improved cardiovascular health and reduced cardiovascular mortality. Previous studies have shown that regular physical activity and high cardiorespiratory fitness both contribute to a reduction in incident atrial fibrillation (AF). However, the risk of AF appears to be paradoxically increased by participation in endurance exercise. Although the mechanisms are not well understood, exercise-induced changes in autonomic tone alongside the development of an arrhythmogenic atrial substrate, appear to contribute to an excess of AF amongst athletes, despite an overall reduction in cardiovascular disease incidence. This review will (i) summarise the evidence showing that regular physical activity and exercise reduces AF incidence, (ii) review the evidence that supports an increase in AF risk by regular endurance exercise, and (iii) discuss the mechanisms and risk factors that may contribute to AF susceptibility amongst otherwise healthy athletes.

To identify the evidence base and evaluate the efficacy of each treatment for postural tachycardia syndrome (POTS) in light of a recent consensus statement highlighting the lack of treatment options with clear benefit to risk ratios for this debilitating condition.The CENTRAL (Cochrane Central Register of Controlled Trials), PubMed, and Embase databases from inception to May 2017 were searched using the terms postural AND tachycardia AND syndrome. A total of 135 full-text publications were screened after excluding duplicates (n=681), conference abstracts (n=467), and records that did not relate to POTS therapy (n=876). We included 28 studies with at least 4 patients with POTS in which symptomatic response was reported after more than 4 weeks of therapy. This review was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. Two investigators independently performed the data extraction and evaluated the quality of evidence.This study comprised 25 case series and 3 small randomized controlled trials that evaluated 755 and 103 patients with POTS, respectively. Interventions directed at increasing intravascular volume, increasing peripheral or splanchnic vascular tone, controlling heart rate, and increasing exercise tolerance demonstrate moderate efficacy (range, 51%-72%). Few data exist on their comparative effectiveness. Significant heterogeneities were seen in terms of patient age, symptom severity, and the measures used to evaluate treatment efficacy.The current evidence base to guide optimal management of patients with POTS is extremely limited. More high-quality collaborative research with standardized reporting of symptom response and treatment tolerability is urgently needed.

Celine Gallagher, Jeroen M. Hendriks, Melissa E. Middeldorp, Adrian D. Elliott, Dennis H. Lau, and Prashanthan Sanders

Whilst high levels of alcohol consumption are known to be associated with atrial fibrillation (AF), it is unclear if any level of alcohol consumption can be recommended to prevent the onset of the condition. The aim of this review is to characterise the association between chronic alcohol intake and incident AF.Electronic literature searches were undertaken using PubMed and Embase databases up to 1 February 2016 to identify studies examining the impact of alcohol on the risk of incident AF. Prospective studies reporting on at least three levels of alcohol intake and published in English were eligible for inclusion. Studies of a retrospective or case control design were excluded. The primary study outcome was development of incident AF. Consistent with previous studies, high levels of alcohol intake were associated with an increased incident AF risk (HR 1.34, 95% CI 1.20-1.49, p0.001). Moderate levels of alcohol intake were associated with a heightened AF risk in males (HR 1.26, 95% CI 1.04-1.54, p=0.02) but not females (HR 1.03, 95% CI 0.86-1.25, p=0.74). Low alcohol intake, of up to 1 standard drink (SD) per day, was not associated with AF development (HR 0.95, 95% CI 0.85-1.06, p=0.37).Low levels of alcohol intake are not associated with the development of AF. Gender differences exist in the association between moderate alcohol intake and AF with males demonstrating greater increases in risk, whilst high alcohol intake is associated with a heightened AF risk across both genders.

The cardiovascular benefits of regular exercise have been well described, including a significant reduction in cardiovascular morbidity and mortality for those meeting recommended guidelines. Yet the impact of physical activity on the incidence of atrial fibrillation (AF) has been less clear. This review seeks to define the optimal dose and duration for the prevention and treatment of AF. In doing so, we review the evidence that supports a decline in AF risk for those who achieve a weekly physical activity dose slightly above the current recommended guidelines. Furthermore, we identify the reduced AF incidence in those individuals who attain a cardiorespiratory fitness of 8 METs (metabolic equivalents of task) or more during maximal exercise testing. Finally, we review the evidence that shows an excess of AF among regular participants of endurance exercise.

Exercise training has considerable health benefits. However, recent research has demonstrated a greater risk of atrial arrhythmias in endurance athletes. The mechanisms promoting atrial fibrillation in athletes are unclear but there seems to be a central role for atrial remodeling, accompanied by autonomic alterations and inflammation. Animal studies have provided unique insights, yet prospective human data are lacking. Treatment options seem to yield similar efficacy to that seen in a nonathletic population and may be justified as an early rhythm control strategy. Further studies are required to enhance understanding of the cardiac adaptations to intensive exercise training.

Rajeev K. Pathak, Adrian Elliott, Melissa E. Middeldorp, Megan Meredith, Abhinav B. Mehta, Rajiv Mahajan, Jeroen M.L. Hendriks, Darragh Twomey, Jonathan M. Kalman, Walter P. Abhayaratna, Dennis H. Lau, Prashanthan Sanders

Background Obesity and atrial fibrillation (AF) frequently coexist. Weight loss reduces the burden of AF, but whether this is sustained, has a dose effect, or is influenced by weight fluctuation is unknown. Objectives This study sought to evaluate the long-term impact of weight loss and weight fluctuation on rhythm control in obese individuals with AF. Methods Of 1,415 consecutive patients with AF, 825 had a body mass index ≥27 kg/m2 and were offered weight management. After screening for exclusion criteria, 355 were included in this analysis. Weight loss was categorized as group 1 (≥10%), group 2 (3% to 9%), and group 3 ( Results There were no differences in baseline characteristics or follow-up among the groups. AF burden and symptom severity decreased more in group 1 compared with groups 2 and 3 (p 5% partially offset this benefit, with a 2-fold (95% confidence interval: 1.0 to 4.3; p = 0.02) increased risk of arrhythmia recurrence. Conclusions Long-term sustained weight loss is associated with significant reduction of AF burden and maintenance of sinus rhythm. (Long-Term Effect of Goal directed weight management on Atrial Fibrillation Cohort: A 5 Year follow-up study [LEGACY Study]; ACTRN12614001123639 )

Sleep-disordered breathing (SDB) severity is largely determined by the number of apneas and hypopneas/h during a single overnight sleep study, following which patients are categorized as no, mild, moderate, or severe SDB [(1)][1]. However, SDB severity in an individual patient may not be stable over