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 remodelling 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 amongst patients with established disease, where adverse atrial remodelling 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 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.
Abstract
Aims
To determine stroke risk in subclinical atrial fibrillation (AF) and temporal association between subclinical AF and stroke.
Methods and results
Pubmed/Embase was searched for studies ...reporting stroke in subclinical AF in patients with cardiac implantable electronic devices (CIEDs). After exclusions, 11 studies were analysed. Of these seven studies reported prevalence of subclinical AF, two studies reported association between subclinical and clinical AF, seven studies reported stroke risk in subclinical AF, and five studies reported temporal relationship between subclinical AF and stroke. Subclinical AF was noted after CIEDs implant in 35% interquartile range (IQR) 34–42 of unselected patients with pacing indication over 1–2.5 years. The definition and cut-off duration (for stroke risk) of subclinical AF varied across studies. Subclinical AF was strongly associated with clinical AF (OR 5.7, 95% CI 4.0–8.0, P < 0.001, I2 = 0%). The annual stroke rate in patients with subclinical AF > defined cut-off duration was 1.89/100 person-year (95% CI 1.02–3.52) with 2.4-fold (95% CI 1.8–3.3, P < 0.001, I2 = 0%) increased risk of stroke as compared to patients with subclinical AF < cut-off duration (absolute risk was 0.93/100 person-year). Three studies provided mean CHADS2 score. In these studies, with mean CHADS2 score of 2.1 ± 0.1, subclinical AF was associated with annual stroke rate of 2.76/100 person-years (95% CI 1.46–5.23). After excluding patients without AF, only 17% strokes occurred in presence of ongoing AF. Subclinical AF was noted in 29% IQR 8–57 within 30 days preceding stroke.
Conclusion
Subclinical AF strongly predicts clinical AF and is associated with elevated absolute stroke risk albeit lower than risk described for clinical AF.
Atrial fibrillation (AF) is a progressive disease. Obesity is associated with progression of AF. This study evaluates the impact of weight and risk factor management (RFM) on progression of the AF.
...As described in the Long-Term Effect of Goal-Directed Weight Management in an Atrial Fibrillation Cohort: A Long-Term Follow-Up (LEGACY) Study, of 1415 consecutive AF patients, 825 had body mass index ≥ 27 kg/m2 and were offered weight and RFM. After exclusion, 355 were included for analysis. Weight loss was categorized as: Group 1 (<3%), Group 2 (3-9%), and Group 3 (≥10%). Change in AF type was determined by clinical review and 7-day Holter yearly. Atrial fibrillation type was categorized as per the Heart Rhythm Society consensus. There were no differences in baseline characteristic or follow-up duration between groups (P = NS). In Group 1, 41% progressed from paroxysmal to persistent and 26% from persistent to paroxysmal or no AF. In Group 2, 32% progressed from paroxysmal to persistent and 49% reversed from persistent to paroxysmal or no AF. In Group 3, 3% progressed to persistent and 88% reversed from persistent to paroxysmal or no AF (P < 0.001). Increased weight loss was significantly associated with greater AF freedom: 45 (39%) in Group 1, 69 (67%) in Group 2, and 116 (86%) in Group 3 (P ≤ 0.001).
Obesity is associated with progression of the AF disease. This study demonstrates the dynamic relationship between weight/risk factors and AF. Weight-loss management and RFM reverses the type and natural progression of AF.
Atrial fibrillation is the most common sustained arrhythmia and is associated with significant morbidity and mortality. The autonomic nervous system has a significant role in the milieu predisposing ...to the triggers, perpetuators and substrate for atrial fibrillation. It has direct electrophysiological effects and causes alterations in atrial structure. In a significant portion of patients with atrial fibrillation, the autonomic nervous system activity is likely a composite of reflex excitation due to atrial fibrillation itself and contribution of concomitant risk factors such as hypertension, obesity and sleep-disordered breathing.
We review the role of autonomic nervous system activation, with focus on changes in reflex control during atrial fibrillation and the role of combined sympatho-vagal activation for atrial fibrillation initiation, maintenance and progression. Finally, we discuss the potential impact of combined aggressive risk factor management as a strategy to modify the autonomic nervous system in patients with atrial fibrillation and to reverse the arrhythmogenic substrate.
•Combined sympathetic and vagal activation creates an atrial fibrillation substrate.•Autonomic nervous system activity is contributed by common concomitant risk factors.•Transient autonomic activation contributes to a dynamic atrial fibrillation substrate.•Autonomic nervous system and atrial fibrillation: a bidirectional relationship•Combined risk factor management can modify the autonomic nervous system.
Abstract
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
Graphical Abstract
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.
...This study sought to evaluate the long-term impact of weight loss and weight fluctuation on rhythm control in obese individuals with AF.
Of 1,415 consecutive patients with AF, 825 had a body mass index ≥ 27 kg/m(2) 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 (<3%). Weight trend and/or fluctuation was determined by yearly follow-up. We determined the impact on the AF severity scale and 7-day ambulatory monitoring.
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 < 0.001 for all). Arrhythmia-free survival with and without rhythm control strategies was greatest in group 1 compared with groups 2 and 3 (p < 0.001 for both). In multivariate analyses, weight loss and weight fluctuation were independent predictors of outcomes (p < 0.001 for both). Weight loss ≥ 10% resulted in a 6-fold (95% confidence interval: 3.4 to 10.3; p < 0.001) greater probability of arrhythmia-free survival compared with the other 2 groups. Weight fluctuation >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.
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).
Aims Prolonged endurance exercise is associated with elevated biomarkers associated with myocardial damage and modest evidence of left ventricular (LV) dysfunction. Recent studies have reported more ...profound effects on right ventricular (RV) function following endurance exercise. We performed a meta-analysis of studies reporting RV function pre-endurance and postendurance exercise. Methods We performed a search of peer-reviewed studies with the criteria for inclusion in the analysis being (1) healthy adult participants; (2) studies examining RV function following an event of at least 90 min duration; (3) studies reporting RV fractional area change (RVFAC), RV strain (S), RV ejection fraction (RVEF) or tricuspid annular plane systolic excursion (TAPSE) and (4) studies evaluating RV function immediately (<1 h) following exercise. Results Fourteen studies were included with 329 participants. A random-effects meta-analysis revealed significant impairments of RV function when assessed by RVFAC (weighted mean difference (WMD) −5.78%, 95% CI −7.09% to −4.46%), S (WMD 3.71%, 95% CI 2.79% to 4.63%), RVEF (WMD −7.05%, 95% CI −12.3% to −1.8%) and TAPSE (WMD −4.77 mm, 95% CI −8.3 to −1.24 mm). Modest RV dilation was evident in studies reporting RV systolic area postexercise (WMD 1.79 cm2, 95% CI 0.5 to 3.08 cm2). In contrast, no postexercise changes in LV systolic function (expressed as LVFAC or LVEF) were observed in the included studies (standardised mean difference 0.03%, 95% CI −0.13% to 0.18%). Conclusions Intense prolonged exercise is associated with a measurable reduction in RV function while LV function is relatively unaffected. Future studies should examine the potential clinical consequences of repeated prolonged endurance exercise on the right ventricle.
Upstream Targets to Treat Atrial Fibrillation Sanders, Prashanthan; Elliott, Adrian D.; Linz, Dominik
Journal of the American College of Cardiology,
12/2017, Letnik:
70, Številka:
23
Journal Article
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