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AliveCor is a smartphone electrocardiography device (iECG) providing automated heart rate (HR) and rhythm determination. Atrial fibrillation (AF) in horses often is paroxysmal and rapid ECG acquisition is needed for diagnostic confirmation. iECGs were collected post‐race from 15 horses with AF and 64 horses in sinus rhythm (SR). Results of manual assessment were compared to 3 commercial algorithms for HR and rhythm. Agreement between manually derived HR (HRM) and HR derived by the AliveECG Vet (HRVET) and Kardia version‐1 (KV1HR) and Kardia advanced (KADVHR) algorithms was quantified by the Bland–Altman limits of agreement test. Agreement between manual rhythm classification and KV1 and KADV algorithms for AF and SR was calculated by the Kappa statistical coefficient. The agreement (bias, 95% limits), between HRM and HRVET was 7.1 BPM (−29 to 43) in AF and −4.2 BPM (−38 to 30) in SR, between HRM and KV1HR, was −0.3 BPM (−31 to 30) in AF and 0.2 BPM (−3 to 4) in SR, and between HRM and KADVHR was 7.0 BPM (−29 to 43) in AF and 0.2 BPM (−3.9 to 4.2) in SR. Agreement between manual rhythm classification and KV1 was 0.36 (0.13–0.59), and KADV was 0.84 (0.68–0.99). Sensitivity and specificity for identification of AF and SR of the KV1 algorithm were 60, 100% and 83, 100%, respectively, and of KADV was 87, 100% and 93, 100% respectively. The Kardia algorithms improved precision for HR determination in SR but not AF. The advanced algorithm accurately distinguished between AF and SR. The iECG is suitable for recording episodes of AF following exercise. [ABSTRACT FROM AUTHOR]

Atrial fibrillation (AF) is highly prevalent in the Australian community, ranking amongst the highest globally. The consequences of AF are significant. Stroke, dementia and heart failure risk are increased substantially, hospitalisations are amongst the highest for all cardiovascular causes, and Australians living with AF suffer from substantial symptoms that impact quality of life. Australian research has made a significant impact at the global level in advancing the care of patients living with AF. However, new strategies are required to reduce the growing incidence of AF and its associated healthcare demand. The Australian Cardiovascular Alliance (ACvA) has led the development of an arrhythmia clinical theme with the objective of tackling major research priorities to achieve a reduction in AF burden across Australia. In this summary, we highlight these research priorities with particular focus on the strengths of Australian research and the strategies needed to move forward in reducing incident AF and improving outcomes for those who live with this chronic condition., (Crown Copyright © 2024. Published by Elsevier B.V. All rights reserved.)

Background: Recent advancements in minimally invasive surgery for correction of hallux abductovalgus has increased the popularity of this technique. To date, the incidence of complications with this updated technique has not been evaluated., Methods: The purpose of this systematic review was to determine the incidence of complications of third-generation minimally invasive chevron osteotomy, with or without an Akin osteotomy, for the correction of hallux abductovalgus. We conducted a systematic review of electronic databases and relevant peer-reviewed sources as outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for the preparation of systematic reviews. Studies that reported hallux abductovalgus deformities corrected with minimally invasive surgery and fixated with one or two screws, provided detailed descriptions of all complications, and had mean follow-up of 12 months or more were included., Results: Of 80 studies identified, nine (11.25%) met the inclusion criteria (N = 766 feet). Three of these studies were prospective and involved 426 feet. The weighted mean age for the entire cohort was 50.88 years (17-87 years), and the weighted mean follow-up was 27.65 months (12-66 months). The total incidence of complications was 21.28% (163 of 766 feet). Among the most reported complications were reoperation, postoperative infection, reoccurrence of hallux abductovalgus, and nerve injury., Conclusions: This systematic review revealed that this updated minimally invasive surgery technique provides a safe and reproducible surgical option to correct hallux abductovalgus deformities, with an incidence of complications comparable with that of open correction for this forefoot deformity.

Aim: Blood pressure (BP) responses to exercise are frequently measured, with the concern that greater increases are a marker of disease. We sought to characterize the normal exercise BP response in healthy adults and its relationships with age, sex, and fitness., Methods: 589 participants (median age 46 [IQR 24-56] years, 81% male) underwent cardiopulmonary exercise testing with repeated, automated BP measures. An exaggerated maximal systolic BP (SBPmax) was defined from current guidelines as ≥210 mmHg in males and ≥190 mmHg in females. Individual linear regression analyses defined the relationship between BP and workload (SBP/W-slope and DBP/W-slope). Participants with or without an exaggerated SBPmax and above or below median SBP/W-slope were compared., Results: An exaggerated SBPmax was found in 51% of males and 64% of females and was more prevalent in endurance-trained athletes (males 58%, females 72%, p<0.001). The mean SBP/W-slope was lower in males (0.24±0.10 mmHg/W) than females (0.27±0.12 mmHg/W), p=0.031. In both sexes, peak oxygen uptake (VO2peak) was inversely correlated with SBP/W-slope (p<0.01). Those with an exaggerated SBPmax and below-median SBP/W-slope were 10 years younger and had a 20% higher VO2peak, on average (p<0.001). A non-exaggerated SBPmax and above-median SBP/W-slope was observed in older individuals with the lowest VO2peak., Conclusion: In a large cohort of healthy individuals, an exaggerated SBPmax was common and associated with higher fitness. In contrast, higher SBP indexed to workload was associated with older age, lower fitness, and female sex. Thus, sex, age and fitness should be considered when evaluating BP response to exercise., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: The outcomes of atrial fibrillation (AF) seem to be variable between males and females. We therefore aimed to determine sex differences in weight loss, cardiorespiratory fitness gain, and recurrence and progression of AF following risk factor management., Methods: Of 1415 consecutive patients referred for electrophysiology management of AF, 825 had a body mass index of ≥27 kg/m 2 ; after exclusions, 355 (males, 234; females, 121) were offered risk factor management and participation in a tailored exercise program., Results: Females were older than males (65.5±10.4 versus 62.5±10.6 years; P =0.013) with a higher body mass index (34.1±5.4 versus 32.6±4.1 kg/m 2 ; P =0.003) and more commonly paroxysmal AF (67.8% versus 48.3%; P <0.001). There was no sex difference in clinic attendance (58.7% versus 60%; P =0.82), weight loss ( P =0.86), fitness gain ( P =0.44), or improvement in AF symptoms ( P =0.35). Weight loss (≥10% compared with <10%) was associated with lower total AF recurrence in males (hazard ratio, 0.41 [95% CI, 0.23-0.73]) and females (hazard ratio, 0.41 [95% CI, 0.20-0.83]). Fitness gain (≥2 metabolic equivalents compared with <2 metabolic equivalents) was associated with lower total AF recurrence in females (hazard ratio, 0.13 [95% CI, 0.05-0.30]) but not in males (hazard ratio, 0.63 [95% CI, 0.38-1.04]; P =0.002). There was a trend toward more reversal from persistent to paroxysmal AF in males compared with females (21.8% versus 14.0%; P =0.079)., Conclusions: Males and females with AF demonstrate a similar degree of weight loss and fitness gain through structured risk factor management. However, fitness had a much greater benefit for total arrhythmia recurrence in females compared with males, whereas there was a trend toward more AF reversal in males., Registration: URL: https://anzctr.org.au; Unique identifier: ACTRN12614001123639., Competing Interests: Dr Sanders reports having served on the advisory board of Medtronic, Abbott Medical, Boston Scientific, CathRx, and PaceMate. Dr Sanders reports that the University of Adelaide has received on his behalf research funding, lecture, and consulting fees from Medtronic, Abbott Medical, Boston Scientific, and Microport. Dr Pathak reports having served on the advisory board of Medtronic, Abbott Medical, and Boston Scientific. Dr Pathak reports that Canberra Heart Rhythm Foundation has received on his behalf lecture and consulting fees from Medtronic, Abbott Medical, Boston Scientific, and Biotronik. Dr Pathak reports that Canberra Heart Rhythm Foundation has received on his behalf research funding from Medtronic, Abbott Medical, Boston Scientific, and Biotronik.

Background: Reduced cardiorespiratory fitness (CRF) is an independent risk factor for the progression of atrial fibrillation (AF). We hypothesized that reduced CRF is associated with structural, functional, and electrical remodeling of the left atrium., Objectives: This study sought to correlate objectively assessed CRF with functional and electrical left atrial (LA) parameters using invasive and noninvasive assessments., Methods: Consecutive patients with symptomatic AF undergoing catheter ablation were recruited. CRF was objectively quantified pre-ablation by using cardiopulmonary exercise testing. Using peak oxygen consumption, participants were classified as preserved CRF (>20 mL/kg/min) or reduced CRF (<20 mL/kg/min). LA stiffness was assessed invasively with hemodynamic monitoring and imaging during high-volume LA saline infusion. LA stiffness was calculated as ΔLA diameter/ΔLA pressure over the course of the infusion. LA function was assessed with echocardiographic measures of LA emptying fraction and LA strain. Electrical remodeling was assessed by using high-density electroanatomical maps for LA voltage and conduction., Results: In total, 100 participants were recruited; 43 had reduced CRF and 57 had preserved CRF. Patients with reduced CRF displayed elevated LA stiffness (P = 0.004), reduced LA emptying fraction (P = 0.006), and reduced LA reservoir strain (P < 0.001). Reduced CRF was also associated with reduced LA voltage (P = 0.039) with greater heterogeneity (P = 0.027) and conduction slowing (P = 0.04) with greater conduction heterogeneity (P = 0.02). On multivariable analysis, peak oxygen consumption was independently associated with LA stiffness (P = 0.003) and LA conduction velocities (P = 0.04)., Conclusions: Reduced CRF in patients with AF is independently associated with worse LA disease involving functional and electrical changes. Improving CRF may be a target for restoring LA function in AF., Competing Interests: Funding Support and Author Disclosures This study was supported by the Center for Heart Rhythm Disorders at the University of Adelaide. Drs Ariyaratnam, Mishima, Kadhim, Emami, and Fitzgerald are supported by Postgraduate Scholarships from the University of Adelaide. Dr Elliott is supported by a Future Leader Fellowship from the National Heart Foundation of Australia. Dr Sanders is supported by an Investigator Grant from the National Health and Medical Research Council of Australia. Dr Emami reports that the University of Adelaide has received consulting fees on his behalf from Medtronic and Biosense Webster. Dr Sanders has served on the advisory board of Medtronic, Abbott Medical, Boston Scientific, PaceMate, and CathRx; and reports that the University of Adelaide has received on his behalf lecture and/or consulting fees from Medtronic, Boston Scientific, and Abbott Medical, and that the University of Adelaide has received on his behalf research funding from Medtronic, Abbott Medical, Boston Scientific, and MicroPort CRM. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. All rights reserved.)

Background: Diagnosis of heart failure with preserved ejection fraction (HFpEF) in patients with atrial fibrillation (AF) represents a significant clinical challenge. Two diagnostic scoring tools have been developed to aid the noninvasive diagnosis of HFpEF: the HFA-PEFF (Heart Failure Association Pre-test assessment, Echocardiography and natriuretic peptide, Functional testing, Final etiology) and the H 2 FPEF scoring systems., Objectives: The purpose of this study was to evaluate the performance of these 2 scoring tools for the diagnosis of HFpEF against a gold standard of invasive evaluation in a cohort of patients with AF., Methods: The authors recruited consecutive patients with symptomatic AF and preserved ejection fraction who were scheduled for an AF ablation procedure. Gold-standard invasive diagnosis of HFpEF was performed at the AF ablation procedure using mean left atrial pressure at rest and following infusion of 500 mL fluid. Each participant was scored according to the noninvasive HFA-PEFF and H 2 FPEF scoring systems. Sensitivity and specificity analyses were performed to assess the accuracy of these scoring systems in diagnosing HFpEF., Results: In total, 120 participants were recruited. HFpEF was diagnosed invasively in 88 (73.3%) participants, whereas 32 (26.7%) had no HFpEF. Using the HFA-PEFF score, 38 (31.7%) participants had a high probability of HFpEF and 82 (68.3%) had low/intermediate probability of HFpEF. Using the H 2 FPEF tool, 72 (60%) participants had a high probability of HFpEF and 48 (40%) had intermediate probability. A high HFA-PEFF (≥5 points) score could diagnose HFpEF with a sensitivity of 40% and a specificity of 91%, and a high H 2 FPEF score (≥6 points) could diagnose HFpEF with a sensitivity of 69% and specificity of 66%. Overall diagnostic accuracy was similar using both tools (AUC: 0.663 vs 0.707, respectively; P = 0.636)., Conclusions: Against a gold standard of invasively diagnosed HFpEF, the HFA-PEFF and H 2 FPEF scores demonstrate only moderate accuracy in patients with AF and should be utilized with caution in this cohort of patients. (Characterising Left Atrial Function and Compliance in Atrial Fibrillation; ACTRN12620000639921)., Competing Interests: Funding Support and Author Disclosures Drs Ariyaratnam, Mishima, Kadhim, Emami, Fitzgerald, Stokes, and Thiyagarajah are supported by Postgraduate Scholarships from the University of Adelaide. Dr Sanders is supported by a Practitioner Fellowship from the National Health and Medical Research Council of Australia; and the University of Adelaide has received on his behalf lecture and/or consulting fees from Medtronic, Boston Scientific, and Abbott Medical, and research funding from Medtronic, Abbott Medical, Boston Scientific, and Microport CRM. Dr Elliott is supported by a Future Leader Fellowship from the National Heart Foundation of Australia. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Exercise-induced cardiac remodeling can be profound, resulting in clinical overlap with dilated cardiomyopathy, yet the significance of reduced ejection fraction (EF) in athletes is unclear. The aim is to assess the prevalence, clinical consequences, and genetic predisposition of reduced EF in athletes., Methods: Young endurance athletes were recruited from elite training programs and underwent comprehensive cardiac phenotyping and genetic testing. Those with reduced EF using cardiac magnetic resonance imaging (defined as left ventricular EF <50%, or right ventricular EF <45%, or both) were compared with athletes with normal EF. A validated polygenic risk score for indexed left ventricular end-systolic volume (LVESVi-PRS), previously associated with dilated cardiomyopathy, was assessed. Clinical events were recorded over a mean of 4.4 years., Results: Of the 281 elite endurance athletes (22±8 years, 79.7% male) undergoing comprehensive assessment, 44 of 281 (15.7%) had reduced left ventricular EF (N=12; 4.3%), right ventricular EF (N=14; 5.0%), or both (N=18; 6.4%). Reduced EF was associated with a higher burden of ventricular premature beats (13.6% versus 3.8% with >100 ventricular premature beats/24 h; P =0.008) and lower left ventricular global longitudinal strain (-17%±2% versus -19%±2%; P <0.001). Athletes with reduced EF had a higher mean LVESVi-PRS (0.57±0.13 versus 0.51±0.14; P =0.009) with athletes in the top decile of LVESVi-PRS having an 11-fold increase in the likelihood of reduced EF compared with those in the bottom decile ( P =0.034). Male sex and higher LVESVi-PRS were the only significant predictors of reduced EF in a multivariate analysis that included age and fitness. During follow-up, no athletes developed symptomatic heart failure or arrhythmias. Two athletes died, 1 from trauma and 1 from sudden cardiac death, the latter having a reduced right ventricular EF and a LVESVi-PRS >95%., Conclusions: Reduced EF occurs in approximately 1 in 6 elite endurance athletes and is related to genetic predisposition in addition to exercise training. Genetic and imaging markers may help identify endurance athletes in whom scrutiny about long-term clinical outcomes may be appropriate., Registration: URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=374976&isReview=true; Unique identifier: ACTRN12618000716268., Competing Interests: Disclosures None.

Background: Left atrial (LA) function contributes to the augmentation of cardiac output during exercise. However, LA response to exercise in patients with atrial fibrillation (AF) is unknown. We explored the LA mechanical response to exercise and the association between LA dysfunction and exercise intolerance., Methods: We recruited consecutive patients with symptomatic AF and preserved left ventricular ejection fraction (LVEF). Participants underwent exercise echocardiography and cardiopulmonary exercise testing (CPET). Two-dimensional and speckle-tracking echocardiography were performed to assess LA function at rest and during exercise. Participants were grouped according to presenting rhythm (AF vs sinus rhythm). The relationship between LA function and cardiorespiratory fitness in patients maintaining SR was assessed using linear regression., Results: Of 177 consecutive symptomatic AF patients awaiting AF ablation, 105 met inclusion criteria; 31 (29.5 %) presented in AF whilst 74 (70.5 %) presented in SR. Patients in SR augmented LA function from rest to exercise, increasing LA emptying fraction (LAEF) and LA reservoir strain. In contrast, patients in AF demonstrated reduced LAEF and reservoir strain at rest, with failure to augment either parameter during exercise. This was associated with reduced VO 2Peak compared to those in SR (18.4 ± 5.6 vs 22.5 ± 7.7 ml/kg/min, p = 0.003). In patients maintaining SR, LAEF and reservoir strain at rest and during exercise were associated with VO 2Peak , independent of LV function., Conclusion: The maintenance of SR in patients with AF is associated with greater LA reservoir function at rest and greater augmentation with exercise compared to patients in AF. In patients in SR, reduced LA function is associated with reduced exercise tolerance, independent of LV function., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Aims: Exercise training reduces recurrence of arrhythmia and symptom severity amongst patients with symptomatic, non-permanent atrial fibrillation (AF). However, there is little evidence on whether this effect is modified by patient sex. In a sub-analysis from the ACTIVE-AF (A Lifestyle-based, PhysiCal AcTIVity IntErvention for Patients With Symptomatic Atrial Fibrillation) randomized controlled trial, we compared the effects of exercise training on AF recurrence and symptom severity between men and women., Methods and Results: The ACTIVE-AF study randomized 120 patients (69 men, 51 women) with paroxysmal or persistent AF to receive an exercise intervention combining supervised and home-based aerobic exercise over 6 months or to continue standard medical care. Patients were followed over a 12-month period. The co-primary outcomes were recurrence of AF, off anti-arrhythmic medications and without catheter ablation, and AF symptom severity scores. By 12 months, recurrence of AF was observed in 50 (73%) men and 34 (67%) women. In an intention-to-treat analysis, there was a between-group difference in favour of the exercise group for both men [hazard ratio (HR) 0.52, 95% confidence interval (CI): 0.29-0.91, P = 0.022] and women (HR 0.47, 95% CI: 0.23-0.95, P = 0.035). At 12 months, symptom severity scores were lower in the exercise group compared with controls amongst women but not for men., Conclusion: An exercise-based intervention reduced arrhythmia recurrence for both men and women with symptomatic AF. Symptom severity was reduced with exercise in women at 12 months. No difference was observed in symptom severity for men., Registration: Australia and New Zealand Clinical Trials Registry: ACTRN12615000734561., Competing Interests: Conflict of interest: C.V.V. reports lecture and/or consulting fees from Novartis. R.M. reports that the University of Adelaide has received on his behalf lecture and/or consulting fees from Medtronic, Abbott, Pfizer, and Bayer. R.M. reports that the University of Adelaide has received on his behalf research funding from Medtronic, Abbott, and Bayer. D.H.L. reports that the University of Adelaide has received on his behalf lecture and/or consulting fees from Abbott Medical, Boehringer Ingelheim, Bayer, and Pfizer. P.S. reports having served on the advisory board of Boston Scientific, CathRx, Medtronic, Abbott Medical, and PaceMate. P.S. reports that the University of Adelaide has received on his behalf lecture and/or consulting fees from Medtronic, Boston Scientific, Abbott Medical, PaceMate, and CathRx. P.S. reports that the University of Adelaide has received on his behalf research funding from Medtronic, Abbott Medical, Boston Scientific, PaceMate, and Becton Dickinson. All other authors have no disclosures., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: Atrial fibrillation (AF) and heart failure with preserved ejection fraction (HFpEF) commonly coexist. We hypothesize that patients with symptomatic AF but without overt clinical HF commonly exhibit subclinical HFpEF according to established hemodynamic criteria., Objectives: The authors sought to use invasive hemodynamics to investigate the prevalence and implications of subclinical HFpEF in AF ablation patients., Methods: Consecutive symptomatic AF ablation patients were prospectively recruited. Diagnosis of subclinical HFpEF was undertaken by invasive assessment of left atrial pressure (LAP). Participants had HFpEF if the baseline mean LAP was >15 mm Hg and early HFpEF if the mean LAP was >15 mm Hg after a 500-mL fluid challenge. LA compliance was assessed invasively by monitoring the LAP and LA diameter during direct LA infusion of 15 mL/kg normal saline. LA compliance was calculated as Δ LA diameter/ΔLAP. LA cardiomyopathy was further studied with exercise echocardiography and electrophysiology study. Functional impact was evaluated using cardiopulmonary exercise testing and the AF Symptom Severity questionnaire., Results: Of 120 participants, 57 (47.5%) had HFpEF, 31 (25.8%) had early HFpEF, and 32 (26.7%) had no HFpEF. Both HFpEF and early HFpEF were associated with lower LA compliance compared with those without HFpEF (P < 0.001). Participants with HFpEF and early HFpEF also displayed decreased LA emptying fraction (P = 0.004), decreased LA voltage (P = 0.001), decreased VO 2peak (P < 0.001), and increased AF symptom burden (P = 0.002) compared with those without HFpEF., Conclusions: Subclinical HFpEF is common in AF ablation patients and is characterized by a LA cardiomyopathy, decreased cardiopulmonary reserve and increased symptom burden. The diagnosis of HFpEF may identify patients with AF with the potential to benefit from novel HFpEF therapies. (Characterising Left Atrial Function and Compliance in Atrial Fibrillation; ACTRN12620000639921)., Competing Interests: Funding Support and Author Disclosures Drs Ariyaratnam, Mishima, Kadhim, Emami, Malik, and Fitzgerald are supported by Postgraduate Scholarships from the University of Adelaide. Dr Elliott is supported by a Future Leader Fellowship from the National Heart Foundation of Australia. Dr Gallagher is supported by a Postdoctoral Fellowship from the University of Adelaide. Dr Lau is supported by a Mid-career fellowship from The Hospital Research Foundation. Dr Sanders is supported by a Practitioner Fellowship from the National Health and Medical Research Council of Australia. Dr Lau reports that the University of Adelaide has received on his behalf lecture and/or consulting fees from Abbott Medical, Bayer, Biotronik, BMS Pfizer, Boehringer Ingelheim, Medtronic, and MicroPort CRM. Dr Sanders has served on the advisory board of Medtronic, Abbott Medical, Boston-Scientific, Pacemate, and CathRx. Dr Sanders reports that the University of Adelaide has received on his behalf lecture and/or consulting fees from Medtronic, Boston-Scientific, and Abbott Medical; and reports that the University of Adelaide has received on his behalf research funding from Medtronic, Abbott Medical, Boston Scientific, and Microport CRM. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Crown Copyright © 2023. Published by Elsevier Inc. All rights reserved.)

Objective: To examine the associations between specific dietary patterns and incident atrial fibrillation (AF)., Methods: Using data from the UK Biobank, dietary intakes were calculated from 24-hour diet recall questionnaires. Indices representing adherence to dietary patterns (Mediterranean-style, Dietary Approaches to Stop Hypertension (DASH) and plant-based diets) were scored, and ultra-processed food consumption was studied as a percentage of total food mass consumed. Incident AF hospitalisations were assessed in Cox regression models., Results: A total of 121 300 individuals were included, with 4 579 incident AF cases over a median follow-up of 8.8 years. Adherence to Mediterranean-style or DASH diets was associated with a lower incidence of AF in minimally adjusted analyses (HR for highest vs lowest quintile 0.87 (95% CI 0.80-0.96) and HR 0.78 (95% CI 0.71-0.86), respectively). However, associations were no longer significant after accounting for lifestyle factors (HR 0.95 (95% CI 0.87-1.04) and 0.94 (95% CI 0.86-1.04) respectively), with adjustment for body mass index responsible for approximately three-quarters of the effect size attenuation. Plant-based diets were not associated with AF risk in any models. Greatest ultra-processed food consumption was associated with a significant increase in AF risk even in fully adjusted models (HR 1.13 (95% CI 1.02-1.24)), and a 10% increase in absolute intake of ultra-processed food was associated with a 5% increase in AF risk (HR 1.05 (95% CI 1.01-1.08))., Conclusion: With the possible exception of reducing ultra-processed food consumption, these findings suggest that attention to other modifiable risk factors, particularly obesity, may be more important than specific dietary patterns for the primary prevention of AF., Competing Interests: Competing interests: GMM has received research funding from Baylis Medical, is a consultant for Johnson and Johnson and InCarda and holds equity in InCarda. DHL reports that the University of Adelaide has received on his behalf lecture and/or consulting fees from Abbott Medical, Biotronik, Medtronic and MicroPort CRM. JH is an International Advisory Board member for BMJ Heart and reports that Flinders University has received on his behalf lecture and/or consulting feels from Biotronik. PS reports having served on the Advisory Board of Boston Scientific, CathRx, Medtronic, PaceMate and Abbott Medical. PS also reports that the University of Adelaide has received on his behalf lecture, consulting fees and/or research funding from Medtronic, Boston Scientific, Abbott Medical and LivaNova. CXW reports that the University of Adelaide has received on his behalf lecture, travel and/or research funding from Abbott Medical, Bayer, Boehringer Ingelheim, Medtronic, Novartis, Servier, St Jude Medical and Vifor Pharma., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

The left atrium (LA) plays a critical role in receiving pulmonary venous return and modulating left ventricular (LV) filling. With the onset of exercise, LA function contributes to the augmentation in stroke volume. Due to the growing focus on atrial imaging, there is now evidence that structural remodeling and dysfunction of the LA is associated with adverse outcomes including incident cardiovascular disease. In patients with established disease, pathological changes in atrial structure and function are associated with exercise intolerance, increased hospital admissions and mortality, independent of left ventricular function. Exercise training is widely recommended in patients with cardiovascular disease to improve patient outcomes and maintain functional capacity. There are widely documented changes in LV function with exercise, yet less attention has been given to the LA. In this review, we first describe LA physiology at rest and during exercise, before exploring its association with cardiac disease outcomes including atrial fibrillation, heart failure, and stroke. The adaptation of the LA to short- and longer-term exercise training is evaluated through review of longitudinal studies of exercise training in healthy participants free of cardiovascular disease and athletes. We then consider the changes in LA structure and function among patients with established disease, where adverse atrial remodeling may be implicated in the disease process. Finally, we consider important future directions for assessment of atrial structure and function using novel imaging modalities, in response to acute and chronic exercise.

The Scarf osteotomy is a surgical procedure performed to correct a hallux valgus deformity. Multiple studies have supported use of the procedure with favorable outcomes. In contrast, there have been studies showing a significant complication rate with the procedure. Incidence of complications remains underreported in the literature. We performed a systemic review and meta-analysis examining a wide range of reported complications and associated clinical outcomes from the Scarf osteotomy. One hundred and sixteen publications were identified and 25 (21.6%) met our inclusion criteria. A total of 1583 Scarf procedures were included. Weighted mean follow-up was 26.4 months [range 12-168 months]. We found a 5.1% rate of recurrence, 3.5% rate of troughing, 1.0% rate of avascular necrosis, 1.8% rate of nonunion, 2.7% rate of malunion, 2.4% rate of infection, 5.3% rate of complex regional pain syndrome, and 3.4% rate of hallux varus. An average decrease in intermetatarsal angle of 6.3° was observed. No statistical difference was found in outcomes when comparing Scarf versus Scarf with additional procedure performed at time of surgery. To our knowledge, this systematic review and meta-analysis contains the highest number of Scarf procedures analyzed and presents complication rates on multiple adverse outcomes., (Copyright © 2022 the American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.)

The global prevalence of atrial fibrillation (AF) has increased substantially over the past three decades and is currently approximately 60 million cases. Incident AF and its clinical consequences are largely the result of risk factors that can be modified by lifestyle changes. In this Review, we provide evidence that the lifetime risk of AF is modified not only by sex and race but also through the clinical risk factor and comorbidity burden of individual patients. We begin by summarizing the epidemiology of AF, focusing on non-modifiable and modifiable risk factors, as well as targets and strategies for the primary prevention of AF. Furthermore, we evaluate the role of modifiable risk factors in the secondary prevention of AF as well as the potential effects of risk factor interventions on the frequency and severity of subsequent AF episodes. We end the Review by proposing strategies that require evaluation as well as global policy changes that are needed for the prevention of incident AF and the management of recurrent episodes in patients already affected by AF., (© 2023. Crown.)

Background: There is a paucity of data on the association between respiratory function and atrial fibrillation (AF). This study aimed to assess the relationship between forced expiratory volume (FEV1), forced vital capacity (FVC), and FEV1/FVC and incident AF., Methods: We performed an analysis of prospectively collected data from the UK Biobank. We included all participants with available spirometry and excluded those with prior AF. Incident AF was ascertained through hospitalisation and death records, and dose-response associations were assessed by means of multivariable Cox regression analysis with adjustment for known AF risk factors., Results: We studied 348,219 white individuals (54.1% female) with a median age of 58.1 years (interquartile range [IQR] 50.8-63.5 years). Over a median follow-up time of 11.5 years (IQR 11.0-12.6 years), a total of 18,188 incident AF events occurred. After standardisation to sex, age, and height, the risk of AF consistently increased with decreasing FEV1 percentage predicted, FEV1 z score, and FVC z score. The risk of AF linearly increased with decreasing FEV1/FVC ratio, and those that had airway obstruction as defined by FEV1/FVC ratio < 0.70 had a 23% greater risk of incident AF (adjusted hazard ratio [aHR] 1.23, 95% confidence interval [CI] 1.19-1.28) compared with those without airway obstruction. Patients with known chronic obstructive pulmonary disease and asthma were at 40% (aHR 1.40, 95% CI 1.29-1.51) and 17% (aHR 1.17, 95% CI 1.12-1.22) increased risk of incident AF respectively., Conclusions: These findings indicate that reduced ventilatory function is associated with increased risk of AF independently from age, sex, smoking, and other known AF risk factors., (Crown Copyright © 2023. Published by Elsevier Inc. All rights reserved.)

Background: There are limited data on the effect of exercise interventions on atrial fibrillation (AF) recurrence and symptoms., Objectives: The aim of this study was to determine the efficacy of an exercise and physical activity intervention on AF burden and symptoms among patients with symptomatic AF., Methods: This prospective, randomized controlled trial included 120 patients with paroxysmal or persistent, symptomatic AF, randomized 1:1 to receive an exercise intervention, combining home and supervised aerobic exercise over 6 months, or to receive usual care. The coprimary outcomes were: 1) AF recurrence, off antiarrhythmic medications and without catheter ablation; and 2) symptom severity assessed by using a validated questionnaire., Results: By 12 months, freedom from AF was achieved in 24 (40%) of 60 patients in the exercise group and 12 (20%) of 60 patients in the control group (HR: 0.50: 95% CI: 0.33 to 0.78). At 6 months, AF symptom severity was lower in the exercise group compared with the control group (mean difference -2.3; 95% CI: -4.3 to -0.2; P = 0.033). This difference persisted at 12 months (-2.3; 95% CI: -4.5 to -0.1; P = 0.041). Total symptom burden was lower at 6 months in the exercise group but not at 12 months. Peak oxygen consumption was increased in the exercise group at both 6 and 12 months. There were no between-group differences in cardiac structure or function, body mass index, or blood pressure., Conclusions: Participation in an exercise-based intervention over 6 months reduced arrhythmia recurrence and improved symptom severity among patients with AF. (A Lifestyle-based, PhysiCal AcTIVity IntErvention for Patients With Symptomatic Atrial Fibrillation [the ACTIVE-AF Study]; ACTRN12615000734561)., Competing Interests: Funding Support and Author Disclosures This study was supported by funding from the National Heart Foundation of Australia through a postdoctoral fellowship to Dr Elliott. Dr Mahajan is supported by a mid-career fellowship from The Hospital Research Foundation. Drs Middeldorp and Gallagher are supported by postdoctoral fellowships from the University of Adelaide. Dr Hendriks is supported by a Future Leader Fellowship from the Australian Heart Foundation. Dr Sanders is supported by a Practitioner Fellowship from the National Health and Medical Research Council of Australia. The University of Adelaide has received on behalf of Dr Mahajan lecture and/or consulting fees from Medtronic, Abbott, Pfizer, and Bayer; and the University of Adelaide has also received on behalf of Dr Mahajan research funding from Medtronic, Abbott, and Bayer. Flinders University has received on behalf of Dr Hendriks lecture and/or consulting fees from Biotronik. The University of Adelaide has received on behalf of Dr Lau lecture and/or consulting fees from Abbott Medical, Boehringer Ingelheim, Bayer, and Pfizer. Dr Sanders has served on the advisory board of Boston Scientific, CathRx, Medtronic, Abbott Medical, and PaceMate. The University of Adelaide has received on behalf of Dr Sanders lecture and/or consulting fees from Medtronic, Boston Scientific, Abbott Medical, PaceMate, and CathRx; the University of Adelaide has also received on behalf of Dr Sanders research funding from Medtronic, Abbott Medical, Boston Scientific, PaceMate, and MicroPort. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Crown Copyright © 2023. Published by Elsevier Inc. All rights reserved.)

Background: Heart rate reserve (HRR) is used to guide exercise training in patients with cardiovascular disease, primarily as a surrogate for oxygen uptake reserve (VO2R) as a marker of metabolic demand. However, the relationship between HRR and VO2R in patients with atrial fibrillation (AF) is not well described. We aimed to assess the validity of HRR as a surrogate for VO2R to guide exercise intensity in AF patients., Methods: One hundred one patients with non-permanent AF undertaking a cardiopulmonary exercise test (CPET) were prospectively enrolled. HR and VO2 values were recorded throughout exercise to determine HRR and VO2R at each workload. Linear regression was used to calculate the slope and y-intercept for HRR versus VO2R with an equivalent slope defined as 1 and y-intercept of 0. The impact of rhythm during exercise, beta blockers and chronotropic incompetence (CI) on the HRR-VO2R relationship was also assessed., Results: The slope of HRR-VO2R was 0.79±0.4, indicating a significant difference from an assumed slope of 1.0 (mean difference: -0.21, 95% CI: -0.30 to -0.12, P<0.001). The mean y-intercept slope was 20.1±41.6, differing significantly from 0 (mean difference: 20.1, 95% CI: 11.9-28.3, P<0.001). The presence of AF during CPET, beta-blockers or chronotropic incompetence did not independently alter the association between VO2R and HRR., Conclusions: HRR is not equivalent to VO2R in AF patients. There was no significant effect of rhythm status, chronotropic incompetence or beta-blockers on this relationship. These findings highlight that the HR prescription of exercise intensity in AF patients should be guided by an individualised HRR-VO2R relationship.

Aims: There is a paucity of epidemiological evidence on alcohol and the risk of bradyarrhythmias. We thus characterized associations of total and beverage-specific alcohol consumption with incident bradyarrhythmias using data from the UK Biobank., Methods and Results: Alcohol consumption reported at baseline was calculated as UK standard drinks (8 g alcohol)/week. Bradyarrhythmia events were defined as sinus node dysfunction (SND), high-level atrioventricular block (AVB), and permanent pacemaker implantations. Outcomes were assessed through hospitalization and death records, and dose-response associations were characterized using Cox regression models with correction for regression dilution bias. We studied 407 948 middle-aged individuals (52.4% female). Over a median follow-up time of 11.5 years, a total of 8 344 incident bradyarrhythmia events occurred. Increasing total alcohol consumption was not associated with an increased risk of bradyarrhythmias. Beer and cider intake were associated with increased bradyarrhythmia risk up to 12 drinks/week; however, no significant associations were observed with red wine, white wine, or spirit intake. When bradyarrhythmia outcomes were analysed separately, a negative curvilinear was observed for total alcohol consumption and risk of SND, but no clear association with AVB was observed., Conclusion: In this predominantly White British cohort, increasing total alcohol consumption was not associated with an increased risk of bradyarrhythmias. Associations appeared to vary according to the type of alcoholic beverage and between different types of bradyarrhythmias. Further epidemiological and experimental studies are required to clarify these findings., Competing Interests: Conflict of interest: J.M.L.H. reports that the University of Adelaide has received on his behalf lecture and/or consulting fees from Medtronic and Pfizer/BMS. D.H.L. reports the University of Adelaide has received on his behalf lecture and/or consulting fees from Abbott Medical, Bayer, Biotronik, Boehringer Ingelheim, Medtronic, Microport, and Pfizer/BMS. P.S. reports having served on the advisory board of Medtronic, Abbott Medical, Boston Scientific, CathRx, and PaceMate. P.S. reports that the University of Adelaide has received on his behalf lecture and/or consulting fees from Medtronic, Abbott Medical, and Boston Scientific. P.S. reports that the University of Adelaide has received on his behalf research funding from Medtronic, Abbott Medical, Boston Scientific, and Microport. C.X.W. reports that the University of Adelaide has received on his behalf lecture, travel, and/or research funding from Abbott Medical, Bayer, Boehringer Ingelheim, Medtronic, Novartis, Servier, St Jude Medical, and Vifor Pharma. The other authors have nothing to disclose., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Aims: To systematic review and meta-analyse the association and mechanistic links between atrial fibrillation (AF) and cognitive impairment., Methods and Results: PubMed, EMBASE, and Cochrane Library were searched up to 27 March 2021 and yielded 4534 citations. After exclusions, 61 were analysed; 15 and 6 studies reported on the association of AF and cognitive impairment in the general population and post-stroke cohorts, respectively. Thirty-six studies reported on the neuro-pathological changes in patients with AF; of those, 13 reported on silent cerebral infarction (SCI) and 11 reported on cerebral microbleeds (CMB). Atrial fibrillation was associated with 39% increased risk of cognitive impairment in the general population [n = 15: 2 822 974 patients; hazard ratio = 1.39; 95% confidence interval (CI) 1.25-1.53, I2 = 90.3%; follow-up 3.8-25 years]. In the post-stroke cohort, AF was associated with a 2.70-fold increased risk of cognitive impairment [adjusted odds ratio (OR) 2.70; 95% CI 1.66-3.74, I2 = 0.0%; follow-up 0.25-3.78 years]. Atrial fibrillation was associated with cerebral small vessel disease, such as white matter hyperintensities and CMB (n = 8: 3698 patients; OR = 1.38; 95% CI 1.11-1.73, I2 = 0.0%), SCI (n = 13: 6188 patients; OR = 2.11; 95% CI 1.58-2.64, I2 = 0%), and decreased cerebral perfusion and cerebral volume even in the absence of clinical stroke., Conclusion: Atrial fibrillation is associated with increased risk of cognitive impairment. The association with cerebral small vessel disease and cerebral atrophy secondary to cardioembolism and cerebral hypoperfusion may suggest a plausible link in the absence of clinical stroke. PROSPERO CRD42018109185., Competing Interests: Conflict of interest: D.L. reports having served on the advisory board of Liva Nova and Medtronic. The University of Adelaide reports receiving on behalf of Dr Linz reports lecture and/or consulting fees from LivaNova, Medtronic, Pfizer, and ResMed. The University of Adelaide reports receiving on behalf of Dr Linz research funding from Sanofi, ResMed, and Medtronic. The University of Adelaide reports receiving on behalf of Dr Lau lecture and/or consulting fees from Abbott, Bayer, Boehringer Ingelheim, Biotronik, and Pfizer. The University of Adelaide reports receiving on behalf of Dr Mahajan lecture and/or consulting fees from Abbott, Medtronic, Bayer, and Pfizer. The University of Adelaide reports receiving on behalf of Dr Mahajan research funding from Abbott and Medtronic. All the remaining authors have declared no conflict of interest., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: Low cardiorespiratory fitness (CRF) and obesity are related to the development and maintenance of atrial fibrillation (AF). The aim of this study was to determine the association between CRF, obesity and left atrial (LA) mechanical parameters in patients with AF., Methods: A cohort of 154 consecutive paroxysmal and persistent AF patients (Age: 62 ± 10, 26% female) referred for exercise stress testing and transthoracic echocardiography were included. We included patients in sinus rhythm with preserved left ventricular ejection fraction who were able to complete a maximal exercise test. Left atrial strain in the reservoir (LASr), booster (LASb) and conduit (LASc) phases were assessed using dedicated software. LA stiffness, emptying fraction (LAEF) and LA to LV ratio were calculated using previously described formulas., Results: CRF was positively associated with LAEF (β = 1.3, 95% CI 0.1-2.3, p = 0.02), reservoir (β = 1.5, 95% CI 0.9-2.1, p < 0.001), booster (β = 0.8, 95% CI 0.4-1.2, p < 0.001) and conduit strain (β = 0.7, 95% CI 0.3-1.1, p = 0.001). We observed an inverse association between CRF and both LA stiffness index (β = -0.02, 95% CI (-0.03)-(-0.01), p < 0.001) and LA to LV ratio (β = -0.03, 95% CI (-0.04)-(-0.01), p < 0.001). Obese patients had significantly higher indexed LA volumes compared to overweight and normal BMI patients. The association between obesity and measures of LA function and stiffness did not reach statistical significance., Conclusion: Among AF patients, higher CRF was independently associated with greater LA function and compliance. Obesity was associated with higher LA volumes yet preserved mechanical function., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Author(s).)

Atrial fibrillation (AF) is the most common cardiac tachyarrhythmia and has a rising global prevalence. Given the increasing burden of AF-related symptoms and complications, new approaches to management are required. Anemia and iron deficiency are common conditions in patients with AF. Furthermore, emerging evidence suggests that the presence of anemia may be associated with worse outcome in these patients. The role of anemia and iron deficiency has been extensively explored in other cardiovascular states, such as heart failure and ischemic heart disease. In particular, the role of iron repletion amongst patients with heart failure is now an established treatment modality. However, despite the strong bidirectional inter-relationship between AF and heart failure, the implications of anemia and iron-deficiency in AF have been scarcely studied. This area is of mechanistic and clinical relevance given the potential that treatment of these conditions may improve symptoms and prognosis in the increasing number of individuals with AF. In this review, we summarise the current published literature on anemia and iron deficiency in patients with AF. We discuss AF complications such as stroke, bleeding, and heart failure, in addition to AF-related symptoms such as exercise intolerance, and the potential impact of anemia and iron deficiency on these. Finally, we summarize current research gaps on anemia, iron deficiency, and AF, and underscore potential research directions., (© 2022. The Author(s).)

In limb and life-threatening diabetic foot infections, transmetatarsal amputations are often indicated as a limb salvage procedure. The aim of this study is to analyze the long-term durability of initially successful transmetatarsal amputations in the diabetic population. We defined a successful transmetatarsal amputation as one which had clinical healing 1 year after surgery. A retrospective review of transmetatarsal amputations completed at our institution over an 11-year period was performed. We identified 83 amputations that met inclusion criteria. The mean follow-up was 4 years. The mean time to surgical healing was 109.8 days. After successfully healing the transmetatarsal amputation the long-term outcomes were analyzed. Re-ulcerations occurred in 44% of the transmetatarsal amputations a mean of 15 months after surgical healing. Patients who re-ulcerated were noted to be significantly younger (p value 0.02) with a significantly higher preprocedure hemoglobin A1c (p value < .001). Additional procedures after successful healing included 13 (15.66%) revision surgeries and 12 (14.46%) more proximal amputations. While transmetatarsal amputations remain a viable and durable limb preserving surgery, all patients who have undergone a transmetatarsal amputation should be monitored lifelong as they remain at risk for re-ulceration and more proximal amputation., (Copyright © 2021 the American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Chronological aging is one of the major risk factors of cardiovascular (CV) disease (CVD); however, the effect of biological aging on CVD and outcomes remain poorly understood. Herein, we evaluated the association between leukocyte telomere length (LTL), a marker of biological age, and CV outcomes., Methods: We searched PubMed, Embase, Ovid Medline, and Web of Science Core Collection for the studies on the association between LTL and myocardial infarction (MI), CV death, and/or CVD risk factors from inception to July 2020. Extracted data were pooled in a random-effects meta-analysis and summarized as risk ratio (RR) and corresponding 95% confidence interval (CI) per LTL tertile., Results: A total of 32 studies (n = 144,610 participants) were included. In a pooled analysis of MI and LTL in a multivariate-adjusted model, the shortest LTL was associated with a 39% higher risk of MI (RR, 1.39; 95% CI, 1.16-1.67; P < 0.001). After adjusting for chronological age and traditional covariance, we showed a 28% increased risk of CV death in the shortest tertile of LTL (RR, 1.28; 95% CI, 1.05-1.56; P = 0.01). Analysis of the studies that investigated the association between CV risk factors and LTL (n = 7) showed that diabetes mellitus is associated with a 46% increased risk of LTL attrition (RR, 1.46; 95% CI, 1.46-2.09; P = 0.039)., Conclusions: This study shows a strong association between LTL, a marker of biological aging, and the risk of MI and CV death. Cardiometabolic risk factors contribute to telomere attrition and therefore accelerates biological aging., (Crown Copyright © 2022. Published by Elsevier Inc. All rights reserved.)

Background: 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)., Objective: 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., Methods: 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., Results: 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 of <26 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., Conclusion: 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., (Copyright © 2021 Heart Rhythm Society. All rights reserved.)

Objectives: This study sought to evaluate the role of cardiac afferent reflexes in atrial fibrillation (AF)., Background: Efferent autonomic tone is not associated with atrial remodeling and AF persistence. However, the role of cardiac afferents is unknown., Methods: Individuals with nonpermanent AF (n = 48) were prospectively studied (23 in the in-AF group and 25 in sinus rhythm [SR]) with 12 matched control subjects. We performed: 1) low-level lower body negative pressure (LBNP), which decreases cardiac volume, offloading predominantly cardiac afferent (volume-sensitive) low-pressure baroreceptors; 2) Valsalva reflex (predominantly arterial high-pressure baroreceptors); and 3) isometric handgrip reflex (both baroreceptors). We measured beat-to-beat mean arterial pressure (MAP) and heart rate (HR). LBNP elicits reflex vasoconstriction, estimated using venous occlusion plethysmography-derived forearm blood flow (∝1/vascular resistance), maintaining MAP. To assess reversibility, we repeated LBNP (same day) after 1-hour low-level tragus stimulation (in n = 5 in the in-AF group and n = 10 in the in-SR group) and >6 weeks post-cardioversion (n = 7)., Results: The 3 groups were well matched for age (59 ± 12 years, 83% male), body mass index, and risk factors (P = NS). The in-AF group had higher left atrial volume (P < 0.001) and resting HR (P = 0.01) but similar MAP (P = 0.7). The normal LBNP vasoconstriction (-49 ± 5%) maintaining MAP (control subjects) was attenuated in the in-SR group (-12 ± 9%; P = 0.005) and dysfunctional in the in-AF group (+11 ± 6%; P < 0.001), in which MAP decreased and HR was unchanged. Valsalva was normal throughout. Handgrip MAP response was lowest in the in-AF group (P = 0.01). Interestingly, low-level tragus stimulation and cardioversion improved LBNP vasoconstriction (-48 ± 15%; P = 0.04; and -32 ± 9%; P = 0.02, respectively)., Conclusions: Cardiac afferent (volume-sensitive) reflexes are abnormal in AF patients during SR and dysfunctional during AF. This could contribute to AF progression, thus explaining "AF begets AF." (Characterisation of Autonomic function in Atrial Fibrillation [AF-AF Study]; ACTRN12619000186156)., Competing Interests: Funding Support and Author Disclosures This study was funded by the Centre for Heart Rhythm Disorders at the University of Adelaide. Drs Malik and Fitzgerald are supported by an Australian Postgraduate Award Scholarship from the University of Adelaide. Dr Elliott is supported by a Future Leader Fellowship from the National Heart Foundation of Australia. Dr Mishima is supported by the Robert J. Craig Postgraduate Scholarship from the University of Adelaide. Dr Middeldorp is supported by Postdoctoral Fellowships from the University of Adelaide. Dr Lau is supported by a Mid-Career Fellowship from the Hospital Research Foundation; and has received lecture and/or consulting fees directed to the University of Adelaide from Abbott Medical, Bayer, Biotronik, BMS Pfizer, Boehringer Ingelheim, Medtronic, and Microport CRM. Dr Sanders is supported by a Practitioner Fellowship from the National Health and Medical Research Council of Australia; has served on the advisory board of Biosense Webster, Medtronic, Abbott, Boston Scientific, Pacemate, and CathRx; has received lecture and/or consulting fees directed to the University of Adelaide from Medtronic, Abbott, and Boston Scientific; and has received research funding directed to the University of Adelaide from Medtronic, Abbott, Boston Scientific, and Microport. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Crown Copyright © 2022. Published by Elsevier Inc. All rights reserved.)

Atrial fibrillation (AF) is associated with exercise intolerance, stroke, and all-cause mortality. However, whether this can be solely attributable to the arrhythmia itself or alternative mechanisms remains controversial. Heart failure with preserved ejection (HFpEF) commonly coexists with AF and may contribute to the poor outcomes associated with AF. Indeed, several invasive hemodynamic studies have confirmed that patients with AF are at increased risk of underlying HFpEF and that the presence of HFpEF may have important prognostic implications in these patients. Mechanistically, AF and HFpEF are closely linked. Both conditions are driven by the presence of common cardiovascular risk factors and are associated with left atrial (LA) myopathy, characterized by mechanical and electrical dysfunction. Progressive worsening of this left atrial (LA) myopathy is associated with both increased AF burden and worsening HFpEF. In addition, there is growing evidence to suggest that worsening LA myopathy is associated with poorer outcomes in both conditions and that reversal of the LA myopathy could improve outcomes. In this review article, we will present the epidemiologic and mechanistic evidence underlying the common coexistence of AF and HFpEF, discuss the importance of a progressive LA myopathy in the pathogenesis of both conditions, and review the evidence from important invasive hemodynamic studies. Finally, we will review the prognostic implications of HFpEF in patients with AF and discuss the relative merits of AF burden reduction vs HFpEF reduction in improving outcomes of patients with AF and HFpEF., (Crown Copyright © 2021 Published by Elsevier Inc. on behalf of Heart Rhythm Society.)

Objectives: This study sought to characterize associations of total and beverage-specific alcohol consumption with incident atrial fibrillation (AF)., Background: Although binge drinking and moderate to high consumption of alcohol are both established risk factors for AF, comparatively less is known about the effect of low alcohol consumption and whether associations differ by specific alcoholic beverages., Methods: Using data from the UK Biobank, total and beverage-specific alcohol consumption was calculated as UK standard drinks (8 g alcohol) per week. Past drinkers and those with a history of AF were excluded. Incident AF events were assessed through hospitalization and death records, and dose-response associations were characterized using Cox regression models with correction for regression dilution bias., Results: We studied 403,281 middle-aged individuals (52.4% female). Over a median follow-up time of 11.4 years (IQR: 10.7-12.3 years), a total of 21,312 incident AF events occurred. A J-shaped association of total alcohol consumption was observed, with lowest risk of AF with fewer than 7 drinks/week. Beverage-specific analyses demonstrated harmful associations of beer/cider consumption with any consumption. In contrast, consumption of red wine, white wine, and spirits up to 10, 8, and 3 drinks/week, respectively, was not associated with increased risk., Conclusions: In this predominantly White population, low levels of alcohol consumption (<7 U.K. standard drinks [56 g alcohol]/week) were associated with lowest AF risk. Low consumption of red and white wine and very low consumption of spirits may not be associated with increased AF risk, whereas any consumption of beer/cider may be associated with harm. These findings may have important implications for the primary prevention of AF that should be explored in future studies., Competing Interests: Funding Support and Author Disclosures Dr Gallagher is supported by a Postdoctoral Fellowship from the University of Adelaide. Dr Elliott is supported by an Early Career Fellowship from the National Heart Foundation of Australia. Dr Linz is supported by the Beacon Research Fellowship from the University of Adelaide. Mr Pitman is supported by a Postgraduate Scholarship from the Hospital Research Foundation. Dr Hendriks is supported by an Early Career Fellowship from the National Heart Foundation of Australia and the Derek Frewin Lectureship from the University of Adelaide. Dr Lau is supported by the Robert J. Craig Lectureship from the University of Adelaide. Dr Sanders is supported by a Practitioner Fellowship from the National Health and Medical Research Council of Australia and by the National Heart Foundation of Australia. Dr Wong is supported by a Mid-Career Fellowship from the Hospital Research Foundation and a Postdoctoral Fellowship from the National Heart Foundation of Australia. Dr Hendriks reports that the University of Adelaide has received on his behalf lecture and/or consulting fees from Medtronic and Pfizer/Bristol Myers Squibb. Dr Lau reports that the University of Adelaide has received on his behalf lecture and/or consulting fees from Abbott Medical, Bayer, Biotronik, Boehringer Ingelheim, Medtronic, Microport, and Pfizer/Bristol Myers Squibb. Dr Sanders has served on the Advisory Boards of Medtronic, Abbott Medical, Boston Scientific, CathRx, and PaceMate; reports that the University of Adelaide has received on his behalf lecture and/or consulting fees from Medtronic, Abbott Medical, and Boston Scientific; and reports that the University of Adelaide has received on his behalf research funding from Medtronic, Abbott Medical, Boston Scientific, and Microport. Dr Wong reports that the University of Adelaide has received on his behalf lecture, travel, and/or research funding from Abbott Medical, Bayer, Boehringer Ingelheim, Medtronic, Novartis, Servier, St Jude Medical, and Vifor Pharma. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2021 American College of Cardiology Foundation. All rights reserved.)

Background: In this study, we sought to estimate the prevalence of concomitant sleep-disordered breathing (SDB) in patients with atrial fibrillation (AF) and to systematically evaluate how SDB is assessed in this population., Methods: We searched Medline, Embase and Cinahl databases through August 2020 for studies reporting on SDB in a minimum 100 patients with AF. For quantitative analysis, studies were required to have systematically assessed for SDB in consecutive AF patients. Pooled prevalence estimates were calculated with the use of the random effects model. Weighted mean differences and odds ratios were calculated when possible to assess the strength of association between baseline characteristics and SDB., Results: The search yielded 2758 records, of which 33 studies (n = 23,894 patients) met the inclusion criteria for qualitative synthesis and 13 studies (n = 2660 patients) met the meta-analysis criteria. The pooled SDB prevalence based on an SDB diagnosis cutoff of apnea-hypopnea index (AHI) ≥ 5/h was 78% (95% confidence interval [CI] 70%-86%; P < 0.001). For moderate-to-severe SDB (AHI ≥ 15/h), the pooled SDB prevalence was 40% (95% CI 32%-48%; P < 0.001). High degrees of heterogeneity were observed (I 2  = 96% and 94%, respectively; P < 0.001). Sleep testing with the use of poly(somno)graphy or oximetry was the most common assessment tool used (in 22 studies, 66%) but inconsistent diagnostic thresholds were used., Conclusions: SDB is highly prevalent in patients with AF. Wide variation exists in the diagnostic tools and thresholds used to detect concomitant SDB in AF. Prospective systematic testing for SDB in unselected cohorts of AF patients may be required to define the true prevalence of SDB in this population., (Crown Copyright © 2021. Published by Elsevier Inc. All rights reserved.)

Aims: The aim of this study is to determine the association between the coronavirus disease 2019 (COVID-19) pandemic and atrial fibrillation (AF) occurrence in individuals with cardiac implantable electronic devices (CIEDs)., Method and Results: Multi-centre, observational, cohort study over a 100-day period during the COVID-19 pandemic (COVID-19) in the USA. Remote monitoring was used to assess AF episodes in patients with a CIED (pacemaker or defibrillator; 20 centres, 13 states). For comparison, the identical 100-day period in 2019 was used (Control). The primary outcomes were the AF burden during the COVID-19 pandemic, and the association of the pandemic with AF occurrence, as compared with 1 year prior. The secondary outcome was the association of AF occurrence with per-state COVID-19 prevalence. During COVID-19, 10 346 CIEDs with an atrial lead were monitored. There were 16 570 AF episodes of ≥6 min transmitted (16 events per 1000 patient days) with a significant increase in proportion of patients with AF episodes in high COVID-19 prevalence states compared with low prevalence states [odds ratio 1.34, 95% confidence interval (CI) 1.21-1.48, P < 0.001]. There were significantly more AF episodes during COVID-19 compared with Control [incident rate ratio (IRR) 1.33, 95% CI 1.25-1.40, P < 0.001]. This relationship persisted for AF episodes ≥1 h (IRR 1.65, 95% CI 1.53-1.79, P < 0.001) and ≥6 h (IRR 1.54, 95% CI 1.38-1.73, P < 0.001)., Conclusion: During the first 100 days of COVID-19, a 33% increase in AF episodes occurred with a 34% increase in the proportion of patients with AF episodes observed in states with higher COVID-19 prevalence. These findings suggest a possible association between pandemic-associated social disruptions and AF in patients with CIEDs., Clinical Trial Registration: Australian New Zealand Clinical Trial Registry: ACTRN12620000692932., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2021. For permissions, please email: journals.permissions@oup.com.)

Introduction: Atrial fibrillation (AF) is associated with significantly impaired quality-of-life. Iron deficiency (ID) is prevalent in patients with AF. Correction of ID in other patient populations with intravenous iron supplementation has been shown to be a safe, convenient and effective way of improving exercise tolerance, fatigue and quality-of-life. The IRON-AF (Effect of Iron Repletion in Atrial Fibrillation) study is designed to assess the effect of iron repletion with intravenous ferric carboxymaltose in patients with AF and ID., Methods and Analysis: The IRON-AF study is a double-blind, randomised controlled trial that will recruit at least 84 patients with AF and ID. Patients will be randomised to receive infusions of either ferric carboxymaltose or placebo, given in repletion and then maintenance doses. The study will have follow-up visits at weeks 4, 8 and 12. The primary endpoint is change in peak oxygen uptake from baseline to week 12, as measured by cardiopulmonary exercise testing (CPET) on a cycle ergometer. Secondary endpoints include changes in quality-of-life and AF disease burden scores, blood parameters, other CPET parameters, transthoracic echocardiogram parameters, 6-minute walk test distance, 7-day Holter/Event monitor burden of AF, health resource utilisation and mortality., Ethics and Dissemination: The study protocol has been approved by the Central Adelaide Local Health Network Human Research Ethics Committee, Australia. The results of this study will be disseminated through publications in peer-reviewed journals and conference presentations., Trial Registration Number: Australian New Zealand Clinical Trials Registry (ACTRN12620000285954)., Competing Interests: Competing interests: DL reports the University of Adelaide has received on his behalf lecture and/or consulting fees from Abbott Medical, Bayer, Biotronik, Boehringer Ingelheim, Medtronic, Microport and Pfizer/BMS. PS reports having served on the advisory board of Medtronic, Abbott Medical, Boston Scientific, CathRx and PaceMate. PS reports that the University of Adelaide has received on his behalf lecture and/or consulting fees from Medtronic, Abbott Medical and Boston Scientific. PS reports that the University of Adelaide has received on his behalf research funding from Medtronic, Abbott Medical, Boston Scientific and Microport. CXW reports that the University of Adelaide has received on his behalf lecture, travel and/or research funding from Abbott Medical, Bayer, Boehringer Ingelheim, Medtronic, Novartis, Servier, St Jude Medical and Vifor Pharma., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Identifying neural substrates of behavior requires defining actions in terms that map onto brain activity. Brain and muscle activity naturally correlate via the output of motor neurons, but apart from simple movements it has been difficult to define behavior in terms of muscle contractions. By mapping the musculature of the pupal fruit fly and comprehensively imaging muscle activation at single-cell resolution, we here describe a multiphasic behavioral sequence in Drosophila . Our characterization identifies a previously undescribed behavioral phase and permits extraction of major movements by a convolutional neural network. We deconstruct movements into a syllabary of co-active muscles and identify specific syllables that are sensitive to neuromodulatory manipulations. We find that muscle activity shows considerable variability, with sequential increases in stereotypy dependent upon neuromodulation. Our work provides a platform for studying whole-animal behavior, quantifying its variability across multiple spatiotemporal scales, and analyzing its neuromodulatory regulation at cellular resolution., Competing Interests: AE, AB, MH, SR, RS, CC, HS, BW No competing interests declared

Background: Reduced exercise capacity and exercise intolerance are commonly reported by individuals with atrial fibrillation (AF). Our objectives were to evaluate the contributing factors to reduced exercise capacity and describe the association between subjective measures of exercise intolerance versus objective measures of exercise capacity., Methods: Two hundred and three (203) patients with non-permanent AF and preserved ejection fraction undergoing cardiopulmonary exercise testing (CPET) were recruited. Clinical characteristics, AF-symptom evaluation, and transthoracic echocardiography measures were collected. Peak oxygen consumption (VO 2peak ) was calculated during CPET as an objective measure of exercise capacity. We assessed the impact of 16 pre-defined clinical features, comorbidities and cardiac functional parameters on VO 2peak ., Results: Across this cohort (Age 66±11 years, 40.4% female and 32% in AF), the mean VO 2peak was 20.3±6.3 mL/kg/min. 24.9% of patients had a VO 2peak considered low (<16 mL/kg/min). In multivariable analysis, echocardiography-derived estimates of elevated left ventricular (LV) filling pressure (E/E') and reduced chronotropic index were significantly associated with lower VO 2peak . The presence of AF at the time of testing was not significantly associated with VO 2peak but was associated with elevated minute ventilation to carbon dioxide production indicating impaired ventilatory efficiency. There was a poor association between VO 2peak and subjectively reported exercise intolerance and exertional dyspnoea., Conclusion: Reduced exercise capacity in AF patients is associated with elevated LV filling pressure and reduced chronotropic response rather than rhythm status. Subjectively reported exercise intolerance is not a sensitive assessment of reduced exercise capacity. These findings have important implications for understanding reduced exercise capacity amongst AF patients and the approach to management in this cohort. (ACTRN12619001343190)., (Copyright © 2020. Published by Elsevier B.V.)

Background: Although physical activity (PA) is an important component of cardiovascular disease prevention and treatment, its role in atrial fibrillation (AF) risk is less well established., Objective: The purpose of this study was to systematically summarize the evidence pertaining to the relationship of PA and risk of AF., Methods: We searched the PubMed and Embase databases for prospective cohort studies reporting the risk of AF associated with a specific PA volume through March 2020. From each study, we extracted the risk associated with a given PA level, in comparison with insufficiently active ("inactive") individuals. The reported risk was normalized to metabolic equivalent of task (MET)-minutes per week. A random-effects meta-analysis was used to compare AF risk between those who met and those who did not meet PA recommendations (450 MET-minutes per week), and a dose-response analysis between the level of PA and the risk of AF was performed., Results: Fifteen studies reporting data from 1,464,539 individuals (median age 55.3 years; 51.7% female) were included. Individuals achieving guideline-recommended level of PA had a significantly lower risk of AF (hazard ratio 0.94; 95% confidence interval 0.90-0.97; P = .001). Dose-response analysis showed that PA levels up to 1900 MET-minutes per week were associated with a lower risk of AF, with less certainty beyond that level., Conclusion: PA at guideline-recommended levels and above are associated with a significantly lower AF risk. However, at 2000 MET-minutes per week and beyond, the benefit is less clear., (Copyright © 2021 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Atrial fibrillation (AF) impacts performance and horse and jockey safety. Understanding the outcomes of AF identified postrace will better inform regulatory policy., Hypothesis/objectives: To investigate the outcomes after episodes of AF identified postrace and determine whether affected horses are at increased risk of additional episodes compared to the general racing population., Animals: Total of 4684 Thoroughbred racehorses., Methods: Race records for Thoroughbred horses racing in Hong Kong from 2007 to 2017 were reviewed. Horses that performed below expectation were examined by cardiac auscultation and ECG. Incidence and recurrence of AF were compared between horses with and without a history of AF and between horses with paroxysmal and persistent episodes using Fisher's exact test., Results: There were 96 135 race starts during the study. Atrial fibrillation was identified in 4.9% of horses, with an overall incidence of 2.7 episodes per 1000 starts. The incidence of AF in horses after any previous episode (12.8 per 1000 starts) was higher than for horses with no previous episode (2.4 per 1000 starts; odds ratio [OR], 5.3; 95% confidence interval [CI], 3.8-7.6). Recurrence was seen in 64% of horses previously treated for persistent AF, which was higher than recurrence in horses with paroxysmal AF (23%; OR, 5.9; 95% CI, 1.6-21.2). Median duration between episodes was 343 days (range, 34-1065)., Conclusions and Clinical Importance: Thoroughbreds are at increased risk of recurrent AF after both paroxysmal and persistent episodes, but the duration of time between episodes varies widely. These findings support a substantial burden of AF among individual Thoroughbred racehorses., (© 2021 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC. on behalf of the American College of Veterinary Internal Medicine.)

Background: Anemia frequently coexists with atrial fibrillation (AF) and has been variably associated with worse outcomes. We performed a systematic review and meta-analysis to comprehensively assess the effect of anemia on mortality, stroke/systemic thromboembolism, and bleeding events in patients with AF., Methods: MEDLINE and Embase were searched from inception until May 2020. Studies examining associations of anemia with the above outcomes in AF patients were included, and maximally adjusted hazard ratios (HRs) meta-analysed. PROSPERO registration number CRD42020171113., Results: Twenty-eight studies involving 365 484 patients (41% female, mean age 74.7 years) were included. The average study follow-up ranged from 0.2 to 4.0 years, and the prevalence of anemia was 16%. Anemia was associated with a 78% increase in all-cause mortality (HR, 1.78; 95% confidence interval [CI], 1.44-2.20), 60% increase in cardiovascular mortality (HR, 1.60; 95% CI, 1.17-2.19), 134% increase in noncardiovascular mortality (HR, 2.34; 95% CI, 1.58-3.47) 15% increase in stroke/systemic thromboembolism (HR, 1.15; 95% CI, 1.01-1.31), 78% increase in major bleeding (HR, 1.78; 95% CI, 1.54-2.05), and 77% increase in gastrointestinal bleeding (HR, 1.77; 95% CI, 1.23-2.55). Sensitivity analyses including studies that reported odds ratios did not result in any material change., Conclusion: Anemia is a frequently observed comorbidity in patients with AF, and is associated with an increased risk of all-cause, cardiovascular and noncardiovascular mortality, stroke/systemic thromboembolism, and major and gastrointestinal bleeding. Future studies are required to explore the causes of anemia in AF, and whether investigation and treatment may be clinically beneficial in affected individuals., (© 2021 Wiley Periodicals LLC.)

Aims: Our objective was to determine the ventricular arrhythmia burden in implantable cardioverter-defibrillator (ICD) patients during COVID-19., Methods and Results: In this multicentre, observational, cohort study over a 100-day period during the COVID-19 pandemic in the USA, we assessed ventricular arrhythmias in ICD patients from 20 centres in 13 states, via remote monitoring. Comparison was via a 100-day control period (late 2019) and seasonal control period (early 2019). The primary outcome was the impact of COVID-19 on ventricular arrhythmia burden. The secondary outcome was correlation with COVID-19 incidence. During the COVID-19 period, 5963 ICD patients underwent remote monitoring, with 16 942 episodes of treated ventricular arrhythmias (2.8 events per 100 patient-days). Ventricular arrhythmia burden progressively declined during COVID-19 (P < 0.001). The proportion of patients with ventricular arrhythmias amongst the high COVID-19 incidence states was significantly reduced compared with those in low incidence states [odds ratio 0.61, 95% confidence interval (CI) 0.54-0.69, P < 0.001]. Comparing patients remotely monitored during both COVID-19 and control periods (n = 2458), significantly fewer ventricular arrhythmias occurred during COVID-19 [incident rate ratio (IRR) 0.68, 95% CI 0.58-0.79, P < 0.001]. This difference persisted when comparing the 1719 patients monitored during both the COVID-19 and seasonal control periods (IRR 0.69, 95% CI 0.56-0.85, P < 0.001)., Conclusions: During COVID-19, there was a 32% reduction in ventricular arrhythmias needing device therapies, coinciding with measures of social isolation. There was a 39% reduction in the proportion of patients with ventricular arrhythmias in states with higher COVID-19 incidence. These findings highlight the potential role of real-life stressors in ventricular arrhythmia burden in individuals with ICDs., Trial Registration: Australian New Zealand Clinical Trial Registry; URL: https://www.anzctr.org.au/; Unique Identifier: ACTRN12620000641998., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2020. For permissions, please email: journals.permissions@oup.com.)

Background The physiology underlying "brain fog" in the absence of orthostatic stress in postural tachycardia syndrome (POTS) remains poorly understood. Methods and Results We evaluated cognitive and hemodynamic responses (cardiovascular and cerebral: heart rate, blood pressure, end-tidal carbon dioxide, and cerebral blood flow velocity (CBFv) in the middle cerebral artery at baseline, after initial cognitive testing, and after (30-minutes duration) prolonged cognitive stress test (PCST) whilst seated; as well as after 5-minute standing in consecutively enrolled participants with POTS (n=22) and healthy controls (n=18). Symptom severity was quantified with orthostatic hypotensive questionnaire at baseline and end of study. Subjects in POTS and control groups were frequency age- and sex-matched (29±11 versus 28±13 years; 86 versus 72% women, respectively; both P ≥0.4). The CBFv decreased in both groups (condition, P =0.04) following PCST, but a greater reduction in CBFv was observed in the POTS versus control group (-7.8% versus -1.8%; interaction, P =0.038). Notably, the reduced CBFv following PCST in the POTS group was similar to that seen during orthostatic stress (60.0±14.9 versus 60.4±14.8 cm/s). Further, PCST resulted in greater slowing in psychomotor speed (6.1% versus 1.4%, interaction, P =0.027) and a greater increase in symptom scores at study completion (interaction, P <0.001) in the patients with POTS, including increased difficulty with concentration. All other physiologic responses (blood pressure and end-tidal carbon dioxide) did not differ between groups after PCST (all P >0.05). Conclusions Reduced CBFv and cognitive dysfunction were evident in patients with POTS following prolonged cognitive stress even in the absence of orthostatic stress.