Atrial fibrillation in highly trained endurance athletes — Description of a syndrome

Thromboembolic prevention in athletes: management of anticoagulation in sports players affected by atrial fibrillation

Atrial fibrillation (AF) is a common cardiac arrhythmia that poses a significant risk of stroke and thromboembolic events. Anticoagulation therapy is essential for preventing stroke in patients with AF. An increasing number of people of all ages, including cardiac patients, approach physical activity as both a leisure-time exercise and a competitive sport. Therefore, patients at risk of AF are increasingly allowed to practice sports activities. Management of oral anticoagulant therapy (OAT) in these patients is extremely challenging because of the need to balance the risks and benefits of medications, considering both hemorrhagic (in case of trauma) and ischemic complications when the drugs are avoided. Official recommendations are limited for these patients and forbid sports that increase the risk of trauma and consequent bleeding in most cases. These recommendations are strongly influenced by the "traditional" management of OAT, which mainly involves coumarin derivatives. Non-vitamin K antagonist direct oral anticoagulants (DOACs), with their more favorable pharmacokinetic-pharmacodynamic profile than that of coumarin derivatives, may represent an opportunity to modify the approach to sports activity in patients with AF and indications for OAT. This study aimed to review the use of anticoagulants in athletes with AF, highlight their efficacy and safety, and provide practical considerations regarding their management.

Long-Term Sports Practice and Atrial Fibrillation: An Updated Review of a Complex Relationship

Atrial fibrillation (AF) is the most common sustained arrhythmia in clinical practice, and it is an enormous burden worldwide because of its high morbidity, disability and mortality. It is generally acknowledged that physical activity (PA) is strongly associated with a significant reduction in the risk of cardiovascular (CV) disease and all-cause mortality. Moreover, it has been observed that moderate and regular physical activity has the potential to reduce the risk of AF, in addition to improving overall well-being. Nevertheless, some studies have associated intense physical activity with an increased risk of AF. This paper aims to review the main related literature to investigate the association between PA and AF incidence and draw pathophysiological and epidemiological conclusions.

The Autonomic Coumel Triangle: A New Way to Define the Fascinating Relationship between Atrial Fibrillation and the Autonomic Nervous System

Arrhythmogenic substrate, modulating factors, and triggering factors (the so-called Coumel's triangle concept) play a primary role in atrial fibrillation (AF) pathophysiology. Several years have elapsed since Coumel and co-workers advanced the concept of the relevance of autonomic nervous system (ANS) influences on atrial cells' electrophysiological characteristics. The ANS is not only associated with cardiac rhythm regulation but also exerts an important role in the triggering and maintenance of atrial fibrillation. This review aims to describe in detail the autonomic mechanisms involved in the pathophysiology of atrial fibrillation (AF), starting from the hypothesis of an "Autonomic Coumel Triangle" that stems from the condition of the fundamental role played by the ANS in all phases of the pathophysiology of AF. In this article, we provide updated information on the biomolecular mechanisms of the ANS role in Coumel's triangle, with the molecular pathways of cardiac autonomic neurotransmission, both adrenergic and cholinergic, and the interplay between the ANS and cardiomyocytes' action potential. The heterogeneity of the clinical spectrum of the ANS and AF, with the ANS playing a relevant role in situations that may promote the initiation and maintenance of AF, is highlighted. We also report on drug, biological, and gene therapy as well as interventional therapy. On the basis of the evidence reviewed, we propose that one should speak of an "Autonomic Coumel's Triangle" instead of simply "Coumel's Triangle".

Atrial fibrillation and sympatho-vagal imbalance: from the choice of the antiarrhythmic treatment to patients with syncope and ganglionated plexi ablation

For several years, the autonomic nervous system has played a central role in the pathophysiological mechanism of atrial fibrillation (AF), so much so that it has been considered one of the cornerstones of Coumel's triangle. The clinical and therapeutic management of AF secondary to sympatho-vagal imbalance represents one of the most important examples of how precision medicine should be applied. Increasing knowledge of this kind of arrhythmias has made it possible to select specific antiarrhythmic drugs and to diversify their use according to vagal or adrenergic AF forms. Ablative strategies, such as cardioneuroablation and non-direct cardiac neuromodulation methods (such as renal denervation and peripheral vagal stimulation), have gradually emerged. In the possibly near future, there will be a development of new acquisitions regarding new pharmacological therapeutic strategies and gene therapy. Finally, finding an AF in patients experiencing syncopal episodes opens a whole chapter regarding interesting, but also complex, diagnostic and therapeutic strategies, ranging from neurally mediated forms to convulsive seizure that could also increase the risk of sudden death.

Assessment of P Wave Indices in Healthy Standardbred Horses

P wave indices are used as non-invasive electrocardiographic markers of atrial remodelling in humans. Few studies have investigated their use in animals. The aim of this study was to measure P wave duration and P wave dispersion (Pd) in healthy standardbred horses and investigate variables that might influence these measurements. A 12-lead electrocardiogram was recorded at rest and P wave indices were calculated in 53 horses. A general linear model was used to investigate the main effects: age, bodyweight, sex, resting heart rate, presence of a murmur, exercise status and the number of years raced. There were significant associations with exercise status for both the maximum P wave duration and Pd, with both values being increased in strenuously exercising versus non-active horses. Furthermore, a significant moderate positive correlation was identified between the duration of exercise (number of years raced) and both Pmax and Pd. No other significant associations were identified. These findings are similar to those reported in elite human athletes versus sedentary individuals. The increases in these P wave indices most likely occur due to prolongation and heterogeneity in atrial conduction time, which are associated with structural and electrical remodelling, and may explain the increased risk of atrial fibrillation in athletic horses.

Current Evidence on Prevention of Atrial Fibrillation: Modifiable Risk Factors and the Effects of Risk Factor Intervention

Atrial fibrillation (AF) is one of the most encountered arrhythmias in clinical practice. It is also estimated that the absolute AF burden may increase by greater than 60% by 2050. It is inevitable that AF will become one of the largest epidemics in the world and may pose a major health problem for countries. Although AF rarely causes mortality in the acute period, it causes a significant increase in mortality and morbidity, including a fivefold increase in the risk of stroke, a twofold increase in dementia, and a twofold increase in myocardial infarction in the chronic period. Despite all the advances in the treatment of AF, it is better understood day by day that preventing AF may play a key role in reducing AF and its related complications. Modification of the main modifiable factors such as quitting smoking, abstaining from alcohol, changing eating habits, and exercise seems to be the first step in preventing AF. The strict adherence to the treatment process of secondary causes predisposing to AF such as DM, hypertension, obesity, and sleep apnea is another step in the prevention of AF. Both an individual approach and global public health campaigns can be highly beneficial to reduce the risk of AF. In this review, we aimed to summarize the current evidence on the relationship between modifiable risk factors and AF, and the impact of possible interventions on these factors in preventing or reducing the AF burden in the light of recently published guidelines and studies.

Cost-effectiveness analysis of digital therapeutics for home-based cardiac rehabilitation for patients with atrial fibrillation after catheter ablation

Background

In recent years, numerous guidelines and expert consensuses have recommended that digital technologies and products, such as digital therapeutics (DTx), be incorporated into cardiac rehabilitation (CR).

Objective

The study aims to compare the cost-effectiveness of DTx for home-based CR (HBCR) with that of the conventional HBCR for patients with atrial fibrillation (AF) after catheter ablation in a real-world clinical setting.

Methods

Based on a single-center, prospective, blinded, randomized, parallel controlled trial of DTx-based HBCR for AF patients after catheter ablation, 100 AF patients undergoing catheter ablation were selected and randomized at a 1:1 ratio into a UC group (conventional HBCR) and DT group (DTx-based HBCR). The intervention lasted for 12 weeks. Medical cost data and clinical efficacy data (VO2max) were acquired from trial data. Effect data (QALYs, anxiety and depression status, health beliefs related to cardiovascular disease, and exercise self-efficacy) were obtained from a patient questionnaire. The cost-effectiveness analysis was conducted to assess the economic benefits of DTx-based HBCR versus conventional HBCR, and the robustness of the results was verified by sensitivity analysis.

Results

In the DT group (n = 49), the mean QALYs increased 0.119 ± 0.09, VO2max increased 9.3 ± 8.0 mL/(min*kg), anxiety, depression, health belief, and exercise self-efficacy had improved, and the total medical cost was 75,080.55 ± 19,746.62 CNY. In the UC group (n = 48), the mean QALYs increased 0.077 ± 0.06, VO2max increased 4.9 ± 6.6 mL/(min*kg), anxiety, depression, health belief, and exercise self-efficacy had improved, and the total medical cost was 73,972.66 ± 16,582.04 CNY. The difference in the medical cost was 1107.89 CNY, and the incremental cost-effectiveness ratio was 33,572.42 CNY/QALY, which was lower than the willingness-to-pay threshold of 85,698 CNY (China's per capita GDP in 2022).

Conclusion

DTx-based HBCR is more effective and cost-effective than conventional HBCR.

Broad Electrocardiogram Syndromes Spectrum: From Common Emergencies to Particular Electrical Heart Disorders

Electrocardiogram (ECG) still remains a very useful diagnostic method in modern cardiology. Its broad availability, noninvasiveness and good sensitivity explain why it plays a capital role in the very beginning of the process of diagnosis for every patient, with or without cardiac-related complaints. For the practitioner, good training in ECG interpretation is mandatory. Sometimes, the ECG trace reveals particular aspects that may cause confusion and complicate decision-making. In this article, we present several less common situations underlying the general context and ECG features. The syndromes studied have a high pathological significance and may range from acute emergencies that call for a rapid therapeutical response to chronic syndromes that require prolonged observation, monitoring and risk stratification.

Left Ventricular, Left Atrial and Right Ventricular Strain Modifications after Maximal Exercise in Elite Ski-Mountaineering Athletes: A Feasibility Speckle Tracking Study

Eleven world elite ski-mountaineering (Ski-Mo) athletes were evaluated for pronounced echocardiographic physiological remodeling as the primary aim of our feasibility speckle tracking study. In this context, sports-related cardiac remodeling was analyzed by performing two-dimensional echocardiography, including speckle tracking analysis of the left atrium (LA), right ventricle (RV) and left ventricular (LV) global longitudinal strain (LV-GLS) at rest and post-peak performance. The feasibility echocardiographic speckle tracking analysis was performed on eleven elite Ski-Mo athletes, which were obtained in 2022 during the annual medical examination. The obtained data of the professional Ski-Mo athletes (11 athletes, age: 18-26 years) were compared for different echocardiographic parameters at rest and post-exercise. Significant differences were found for LV-GLS mean (p = 0.0036) and phasic LA conduit strain pattern at rest and post-exercise (p = 0.0033). Furthermore, negative correlation between LV mass and LV-GLS (p = 0.0195, r = -0.69) and LV mass Index and LV-GLS (p = 0.0253, r = -0.66) at rest were elucidated. This descriptive reporting provided, for the first time, a sport-specific dynamic remodeling of an entire elite national team of the Ski-Mo athlete's left heart and elucidated differences in the dynamic deformation pattern of the left heart.

Association between metabolically healthy obesity and risk of atrial fibrillation: taking physical activity into consideration

The modification of physical activity (PA) on the metabolic status in relation to atrial fibrillation (AF) in obesity remains unknown. We aimed to investigate the independent and joint associations of metabolic status and PA with the risk of AF in obese population. Based on the data from UK Biobank study, we used Cox proportional hazards models for analyses. Metabolic status was categorized into metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO). PA was categorized into four groups according to the level of moderate-to-vigorous PA (MVPA): none, low, medium, and high. A total of 119,424 obese participants were included for analyses. MHO was significantly associated with a 35% reduced AF risk compared with MUO (HR = 0.65, 95% CI: 0.57-0.73). No significant modification of PA on AF risk among individuals with MHO was found. Among the MUO participants, individuals with medium and high PA had significantly lower AF risk compared with no MVPA (HR = 0.84, 95% CI: 0.74-0.95, and HR = 0.87, 95% CI: 0.78-0.96 for medium and high PA, respectively). As the severity of MUO increased, the modification of PA on AF risk was elevated accordingly. To conclude, MHO was significantly associated with a reduced risk of AF when compared with MUO in obese participants. PA could significantly modify the relationship between metabolic status and risk of AF among MUO participants, with particular benefits of PA associated with the reduced AF risk as the MUO severity elevated.

Strenuous Endurance Exercise and the Heart: Physiological versus Pathological Adaptations

Although the benefits of regular physical activity on cardiovascular health are well established, the effects of strenuous endurance exercise (SEE) have been a matter of debate since ancient times. In this article, we aim to provide a balanced overview of what is known about SEE and the heart-from epidemiological evidence to recent cardiac imaging findings. Lifelong SEE is overall cardioprotective, with endurance master athletes showing in fact a youthful heart. Yet, some lines of research remain open, such as the need to elucidate the time-course and potential relevance of transient declines in heart function (or increases in biomarkers of cardiac injury) with SEE. The underlying mechanisms and clinical relevance of SEE-associated atrial fibrillation, myocardial fibrosis, or high coronary artery calcium scores also remain to be elucidated. © 2022 American Physiological Society. Compr Physiol 12:1-19, 2022.

Heart rhythm assessment in elite endurance athletes: A better method?

Introduction

Arrhythmias also occur among elite endurance athletes. Conventional diagnostic tools for assessment of arrhythmias suffer from limited availability and usability challenges, particularly under the demanding training conditions of an elite athlete. Among endurance athletes, there is a need for out-of-hospital monitoring to enhance detection of arrhythmias under conditions that are relevant and potentially provocative of underlying pathology. The Norwegian patch ECG247 Smart Heart Sensor has been developed to simplify the assessment of heart rhythm disorders. The current study aimed to evaluate the ECG247 Smart Heart Sensor function and usability in an elite athlete environment.

Methods

A total of 13 professional cyclists from the UNO-X Pro Cycling Team were examined with the ECG247 Smart Heart Sensor during training camp in Spain, December 2021. All ECG data were analyzed by cardiologists at Sorlandet Hospital Arendal, Norway. The athletes also completed a brief questionnaire registering their training (from on-bike monitoring units) and provided self-assessment of usability parameters after the test.

Results

In 8 of 13 athletes (69% male, age 23 ± 4 years), two test periods were performed with different ECG patches, resulting in a total of 21 tests with continuous ECG monitoring. Average total ECG test duration per athlete was 144 ± 47 h (89 ± 24 h/patch). Athletes performed an average of 15 ± 5 training h during each test. The ECG quality from all tests was considered satisfactory for rhythm analysis—also during exercise. The reported usability of the ECG247 Smart Heart Sensor was high, and no athletes reported trouble sleeping or training with the sensor. The automatic arrhythmia algorithm reported episodes of possible arrhythmias in 5 (24%) tests; 2 atrial flutter, 2 supraventricular tachycardia and 1 bradycardia (heart rate <30/min). Manual assessment by physicians verified the episode of bradycardia but revealed normal sinus rhythm in all other tests. No false negative events were identified in over 1,800 h of ECG collection.

Conclusion

The ECG247 Smart Heart Sensor allowed for high quality ECG monitoring with high usability during intensive exercise in athletes.

Longitudinal Associations Between Cumulative Physical Activity and Change in Structure and Function of the Left Side of the Heart: The Tromsø Study 2007–2016

Background

Current knowledge about the relationship between physical activity (PA) and cardiac remodeling is mainly derived from cross-sectional studies of athletes, and there is a knowledge gap of this association in the general adult and elderly population. Therefore, we aimed to explore the longitudinal association between cumulative PA and change in cardiac structure and function in a general adult and elderly population.

Methods

This longitudinal study includes 594 participants from the sixth (Tromsø6, 2007–08) and seventh (Tromsø7, 2015–16) survey of the Tromsø Study. Cardiac structure and function were assessed by echocardiography at two time points, and PA was self-reported by questionnaire at both time points. PA volume was expressed as cumulative PA (Low, Moderate, and Hard) and the association with left atrial (LA) and left ventricular (LV) structure and function was assessed using ANCOVA.

Results

Overall, LA diameter index (LADi) increased significantly more in Hard compared to Moderate PA (+0.08 cm/m², 95% CI 0.01–0.15, p = 0.020) from Tromsø6 to Tromsø7. When stratified by sex or age, higher levels of cumulative PA were associated with increased LADi in males and in participants <65 years only. Indexed LV mass (LVMi) increased significantly more in Moderate than in Low PA (+3.9 g/m^2.7, 95% CI 0.23–7.57, p = 0.037). When stratified by sex or age, these changes in LVMi and indexed LV diameter (LVDi) were only significant in females. No significant associations were observed between cumulative PA and change in relative wall thickness, E/e' ratio, e' velocity, LV ejection fraction, and LADi/LVDi ratio.

Conclusion

Higher levels of cumulative PA were associated with increased LADi in males and participants <65 years, and with increased LVMi and LVDi in females. Despite cardiac chamber enlargement, the pump function of the heart did not change with higher levels of PA, and the atrioventricular ratio was unchanged. Our results indicate that cardiac chamber enlargement is a physiological response to PA.

Atrial fibrillation and sport: need for monitoring

Historically, regular exercise contributed to reduce the arrhythmic burden and improve cardiovascular outcomes in the general population. However, a heightened risk of Atrial Fibrillation (AF) seems to occur mainly amongst endurance athletes. The exact mechanisms are not fully elucidated, but dynamic interactions between electroanatomical changes induced by exercise, the autonomic system, variable triggers, along individual genetic predisposition are the main contributors to AF development in athletes. The type and training load of sports are also crucial in determining the arrhythmogenic milieu predisposing to AF insurgence and perpetuation. Moreover, a sex difference seems to influence an increased risk of AF only in men undergoing strenuous exercise, whereas women appear protected even during more vigorous training. In the absence of solid evidence, the advent of modern technologies could help to monitor and deep investigate the peculiar aspects of AF in these athletes. This review aims to describe the pathophysiology, diagnosis, and management of AF in athletes, shedding light on possible future strategies to face AF in this population.

Electrical and Structural Adaption of Athlete’s Heart and the Impact on Training and Recovery Management in Professional Basketball Players: A Retrospective Observational Study

Introduction

We analyzed data of 27 professional basketball players to prove cardiac remodeling referring echocardiographic parameters, cardiopulmonary exercise testing (CPET), and 12-lead electrocardiogram (ECG) analyses. The aim of our study was to present different characteristics in the athletes, on the one hand signs of a high vagal tone in the 12-lead ECG as criteria of early repolarization (ER), furthermore echocardiographic remodeling parameters and finally the performance in CPET. Therefore, we divided the cohort into a group with signs of ER pattern in the 12-lead ECG and without these criteria and presented the differences in detail.

Materials and Methods

This was a single-center, retrospective study performed in 27 professional basketball players (age: 26.5 ± 7.5 years, male: 27, height: 197.2 ± 12 cm, weight: 100 ± 17 kg, BMI: 25.7 ± 3.4 kg/m2). All participants underwent a sports medicine checkup, ECG analysis, transthoracic echocardiographic examination, and a CPET on a cycle ergometer between 2015 and 2019 during their pre-season preparation time. All individuals were healthy people without cardiological advance anamnesis. After assessment, two groups were built based on electrocardiographic criteria of ER pattern and a group without these criteria and compared against each other for parameters of echocardiographic assessment, CPET, and 12-lead ECG analysis. Data were analyzed with Minitab statistic program (Minitab Inc., State College, PA, United States) and Graph Pad Prism 8.2.1 (279; Graph Pad Software, San Diego, CA, United States) using ANOVA testing with post-hoc testing and unpaired t-testing (p ≤ 0.05).

Retrospectively additional information was collected referring to the management of training sessions, recovery time, and nutrition by interviewing the athletic training staff in order to understand the principles for individual athlete’s training management and physiological and cardiopulmonary interactions.

Results

Comparing professional basketball players with ER pattern to those with no ER pattern, significant differences were found for CPET, echocardiographic, and ECG analysis (p &lt; 0.05). Absolute and relativized peak oxygen uptake (VO2 peak; ER 4120 ± 750 ml/min (39 ± 5.4 ml/kg/min) vs. non-ER 3556 ± 393 ml/min (37.2 ± 5.3 ml/kg/min), p = 0.018) and maximum workload during CPET (ER 310 ± 51.5 Watt (2.94 ± 0.35 W/kg) vs. non-ER 271 ± 32 Watt (2.85 ± 0.49 W/kg), p = 0.026) was higher in athletes with an ER pattern. Furthermore, ER pattern athletes showed a higher enddiastolic left ventricular diameter (LVedd; ER 58.3 ± 7.9 mm vs. non-ER 53.6 ± 3.6 mm, p = 0.048) and a significantly enlarged left atrial (LA) endsystolic diameter (ER 23.33 ± 2.71 mm vs. non-ER 20.47 ± 2.29 mm, p = 0.006) as well as a significantly enlarged right atrial (RA) endsystolic diameter (ER 23.42 ± 2.15 mm vs. non-ER 20.93 ± 3.28 mm, p = 0.033). Significant differences between the two compared groups could be revealed for left ventricular mass Index (LVMI gr/m2; LVMI ER 113 gr/m2 ± 17.5 vs. LVMI non-ER 91.3 gr/m2 ± 15.1, p = 0.002), but no significant differences for the relative wall thickness were found (RWT; RWT ER 0.49 ± 0.11 vs. RWT non-ER 0.38 ± 0.06, p = 0.614).

Conclusion

Professional basketball players with criteria of ER pattern showed different results in CPET and cardiac remodeling as athletes with no ER pattern. These findings should encourage the athletic training staff to emphasize the quality of an individual training schedule for each athlete based on the cardiopulmonary pre-season sport medicine checkup. Nevertheless, echocardiographic findings, ER pattern, and performance in CPET have to be interpreted referring the sport-specific and athlete’s ethnical background.

Associations between physical activity, left atrial size and incident atrial fibrillation: the Tromsø Study 1994-2016

AIMS

Left atrial (LA) enlargement is an independent risk factor for atrial fibrillation (AF). Interestingly, some athletes have increased risk of AF, which may be linked to LA enlargement; however, little is known about the relationship between LA enlargement and AF risk at moderate-level physical activity (PA). We aimed to explore the associations between PA, LA size and risk of incident AF, and if PA can attenuate the risk of AF with LA enlargement.

METHODS

This prospective study followed 2479 participants (52.4% female), free from known cardiac pathology, for median 20.2 years. Participants were followed up for hospital-diagnosed AF, confirmed by electrocardiography, from 1994-95 through 2016. At baseline, LA size was evaluated by anteroposterior LA diameter, and PA was self-reported by questionnaire.

RESULTS

We observed a U-shaped relationship between PA and AF, and moderately active had 32% lower AF risk than inactive (HRadjusted 0.68, 95% CI 0.50 to 0.93). Participants with LA enlargement had 38% higher AF risk compared with participants with normal LA size (HRadjusted 1.38, 95% CI 1.12 to 1.69). However, the increased AF risk with LA enlargement was attenuated by PA; compared with inactive participants with LA enlargement, the AF risk was 45% lower among active with LA enlargement (HRadjusted 0.55, 95% CI 0.39 to 0.79). AF risk in active participants with LA enlargement did not differ from active with normal LA size. These patterns were observed in both men and women, and in participants over/under 65 years.

CONCLUSION

Moderate PA was associated with reduced AF risk, and PA attenuated the increased risk of AF with LA enlargement in both men and women and all age groups.

Exercise Effects On Cardiovascular Disease: From Basic Aspects To Clinical Evidence

Cardiovascular (CV) disease (CVD) remains the leading cause of major morbidity and CVD- and all-cause mortality in most of the world. It is now clear that regular physical activity (PA) and exercise training (ET) induces a wide range of direct and indirect physiologic adaptations and pleiotropic benefits for human general and CV health. Generally, higher levels of PA, ET, and cardiorespiratory fitness (CRF) are correlated with reduced risk of CVD, including myocardial infarction, CVD-related death, and all-cause mortality. Although exact details regarding the ideal doses of ET, including resistance and, especially, aerobic ET, as well as the potential adverse effects of extreme levels of ET, continue to be investigated, there is no question that most of the world's population have insufficient levels of PA/ET, and many also have lower than ideal levels of CRF. Therefore, assessment and promotion of PA, ET, and efforts to improve levels of CRF should be integrated into all health professionals' practices worldwide. In this state-of-the-art review, we discuss the exercise effects on many areas related to CVD, from basic aspects to clinical practice.

Atrial fibrillation and autonomic nervous system: A translational approach to guide therapeutic goals

The autonomic nervous system (ANS) is known to play an important role in the genesis and maintenance of atrial fibrillation (AF). Biomolecular and genetic mechanisms, anatomical knowledges with recent diagnostic techniques acquisitions, both invasive and non-invasive, have enabled greater therapeutic goals in patients affected by AF related to ANS imbalance. Catheter ablation of ganglionated plexi (GP) in the left and right atrium has been proposed in varied clinical conditions. Moreover interesting results arise from renal sympathetic denervation and vagal nerve stimulation. Despite all this, in the scenario of ANS modulation translational strategies we necessary must consider the treatment or correction of dynamic factors such as obesity, obstructive sleep apnea, lifestyle, food, and stress. Finally, new antiarrhythmic drugs, gene therapy and "ablatogenomic" could be represent exciting future therapeutic perspectives.

Balanced Intense Exercise Training Induces Atrial Oxidative Stress Counterbalanced by the Antioxidant System and Atrial Hypertrophy That Is Not Associated with Pathological Remodeling or Arrhythmogenicity

Although regular exercise training is associated with cardiovascular benefits, the increased risk of atrial arrhythmias has been observed after vigorous exercise and has been related to oxidative stress. We aimed at investigating exercise-induced atrial remodeling in a rat model of an athlete’s heart and determining sex-specific differences. Age-matched young adult rats were divided into female exercised, female control, male exercised, and male control groups. After exercised animals completed a 12-week-long swim training protocol, echocardiography and in vivo cardiac electrophysiologic investigation were performed. Additionally, atrial histological and gene expression analyses were carried out. Post-mortem atrial weight data and histological examination confirmed marked atrial hypertrophy. We found increased atrial gene expression of antioxidant enzymes along with increased nitro-oxidative stress. No gene expression alteration was found regarding markers of pathological remodeling, apoptotic, proinflammatoric, and profibrotic processes. Exercise training was associated with a prolonged right atrial effective refractory period. We could not induce arrhythmias by programmed stimulation in any groups. We found decreased expression of potassium channels. Female gender was associated with lower profibrotic expression and collagen density. Long-term, balanced exercise training-induced atrial hypertrophy is not associated with harmful electrical remodeling, and no inflammatory or profibrotic response was observed in the atrium of exercised rats.

Prognostic value of troponin I in atrial fibrillation

OBJECTIVE

To evaluate whether circulating cardiac troponin I (cTnI) levels are associated with worst outcomes in patients with atrial fibrillation (AF).

METHODS

Consecutive patients visiting the emergency room (ER) with a new episode of a previously diagnosed AF or a new diagnosis of AF during ER admission between January 1st, 2010 and December 31st, 2015, were enrolled in the study (n = 2617). After applying exclusion criteria and eliminating repeated episodes, 2013 patients were finally included. Of these, 1080 patients with at least one cTnI measurement in the ER were selected and classified into 4 groups according to cTnI quartiles: Q1 (n = 147) cTnI <10 ng/L (Group 1); Q2 (n = 254): 10-19 ng/L (Group 2); Q3 (n = 409): 20-40 ng/L (Group 3); and Q4 (n = 270): cTnI >40 ng/L (Group 4). The median follow-up period was 47.8 ± 32.8 months. The primary endpoint was all-cause death during the follow-up.

RESULTS

A higher mortality was found in group 4 compared with the other groups (58.9% vs. 28.5%, respectively, p < 0.001), along with, hospitalizations (40.4% vs. 30.7%, p = 0.004), and readmissions due to decompensated heart failure (26.7% vs. 2.5%, p = 0.002). The probability of survival without AF recurrences was lower in the Q4 (p = 0.045). Moreover, cTnI levels >40 ng/L (Q4) were an independent risk factor of death (HR, 2.03; 95% CI, 1.64-2.51; p < 0.001).

CONCLUSION

The assessment of cTnI at ER admission could be a useful strategy for risk stratification of patients diagnosed with AF by identifying a subgroup with medium-term to long-term increased risk of adverse events and mortality.

Incidence, recurrence, and outcome of postrace atrial fibrillation in Thoroughbred horses

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.

Very Low Prevalence and Incidence of Atrial Fibrillation among Bolivian Forager-Farmers

Background

Atrial fibrillation is the most common arrhythmia in post-industrialized populations. Older age, hypertension, obesity, chronic inflammation, and diabetes are significant atrial fibrillation risk factors, suggesting that modern urban environments may promote atrial fibrillation.

Objective

Here we assess atrial fibrillation prevalence and incidence among tropical horticulturalists of the Bolivian Amazon with high levels of physical activity, a lean diet, and minimal coronary atherosclerosis, but also high infectious disease burden and associated inflammation.

Methods

Between 2005-2019, 1314 Tsimane aged 40-94 years (52% female) and 534 Moseten Amerindians aged 40-89 years (50% female) underwent resting 12-lead electrocardiograms to assess atrial fibrillation prevalence. For atrial fibrillation incidence assessment, 1059 (81% of original sample) Tsimane and 310 Moseten (58%) underwent additional ECGs (mean time to follow up 7.0, 1.8 years, respectively).

Findings

Only one (male) of 1314 Tsimane (0.076%) and one (male) of 534 Moseten (0.187%) demonstrated atrial fibrillation at baseline. There was one new (female) Tsimane case in 7395 risk years for the 1059 participants with >1 ECG (incidence rate = 0.14 per 1,000 risk years). No new cases were detected among Moseten, based on 542 risk years.

Conclusion

Tsimane and Moseten show the lowest levels of atrial fibrillation ever reported, 1/20 to ~1/6 of rates in high-income countries. These findings provide additional evidence that a subsistence lifestyle with high levels of physical activity, and a diet low in processed carbohydrates and fat is cardioprotective, despite frequent infection-induced inflammation. Findings suggest that atrial fibrillation is a modifiable lifestyle disease rather than an inevitable feature of cardiovascular aging.

Exercise and Athletic Activity in Atrial Fibrillation

Moderate-intensity exercise improves cardiovascular outcomes. However, mounting clinical evidence demonstrates that long-term, high-intensity endurance training predisposes male and veteran athletes to an increased risk of atrial fibrillation (AF), a risk that is not observed across both genders. Although increased mortality associated with AF in the general population is not shared by athletes, clinically significant morbidities exist (eg, reduced exercise capacity, athletic performance, and quality of life). Additional research is needed to fill current gaps in knowledge pertaining to the natural history, pathophysiologic mechanisms, and management strategies of AF in the athlete.

Consumer wearable technologies to identify and monitor exercise-related arrhythmias in athletes

PURPOSE OF REVIEW

The aim of this study was to synthesize the current evidence supporting and against the use of wearable devices to detect underlying heart conditions in athletes and the most significant limitations.

RECENT FINDINGS

Although several large studies have been conducted to evaluate the ability of wearables devices to identify atrial fibrillation among the general population, no studies evaluating their ability to detect other exercise-related arrhythmias in athletes are very sparse. Most of the studies or case reports are focused on the wearables' reliability and accuracy compared with standard ECG. Only small studies evaluating the accuracy of one wearable device in athletes have been carried out to date. Unfortunately, none of them have investigated their ability to detect specific arrhythmias in the athletic population.

SUMMARY

Rapidly detecting dangerous arrhythmias in a symptomatic athlete continues to be an elusive goal. The use of smartphone ECG monitors can provide diagnostic data in athletes with symptoms that could represent a helpful instrument. However, many uncertainties remain and need to be addressed and validated in large-scale trials to incorporate these devices into the healthcare system and be part of an athlete's daily monitoring and healthcare.

Association between cardiorespiratory fitness, obesity, and incidence of atrial fibrillation

BACKGROUND

The interaction between cardiorespiratory fitness (CRF) and incidence of atrial fibrillation (AF) and the interaction between obesity and incidence of AF have been explored separately. Therefore, we evaluated the association between CRF, body mass index (BMI), and risk of developing AF in a cohort of middle-aged and older US Veterans.

METHODS

Symptom limited exercise tests (ETT) were conducted among 16,397 Veterans (97% male) from January 9,1987 to December 31,2017. No history of AF was evident at the time of the ETTs. CRF was expressed as quartiles of peak metabolic equivalents (METs) achieved within each age decile. Weight status was classified as normal (BMI < 25 kg/m2), overweight (BMI 25-30 kg/m2), obese (BMI 30-35 kg/m2), or severely obese (BMI > 35 kg/m2). Multivariable Cox proportional hazards regression models were used to compare the association between BMI, CRF categories, and incidence of AF.

RESULTS

Over a median follow-up of 10.7 years, 2,155 (13.1%) developed AF. Obese and severely obese subjects had 13% and 32% higher risks for incidence of AF, respectively, vs. normal weight subjects. Overweight and obese subjects in the most fit quartile had 50% decline in AF risk compared to the least-fit subjects. Severely obese subjects had marked increases in AF risk (~50-60%) regardless of fitness level. Risk of developing AF increases with higher BMI and lower CRF.

CONCLUSION

Improving CRF should be advocated when assessing those at risk for developing AF.

The counterintuitive role of exercise in the prevention and cause of atrial fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia, characterized by irregular atrial activity. AF is related to increased risk of thromboembolic events, heart failure, and premature mortality. Recent advances in our understanding of its pathophysiology include a potentially central role for inflammation and presence of cardiovascular risk factors. The role of physical activity and exercise in the development and progression of AF, however, are not yet fully understood. Physical activity is protective for modifiable cardiovascular risk factors, including those associated with AF. Indeed, emerging research has demonstrated beneficial effects of exercise on AF-specific outcomes, including AF recurrence postablation. Counterintuitively, the prevalence of AF in veteran endurance athletes seems higher compared with the general population. In this review, we discuss the novel evidence and underlying mechanisms underpinning the role of exercise as medicine in the development and management of AF but also the counterintuitive detrimental role of excessive endurance exercise. Finally, we advocate regular (but not long-term high-intensity endurance) exercise training as a safe and effective strategy to reduce the risk of incident AF and to minimize the associated risk of secondary cardiovascular events.

Atrial size and sports. A great training for a greater left atrium: how much is too much?

Athlete's heart results from physiological adaptations to the increased demands of exercise, and left atrial (LA) enlargement (LAE) is a fundamental component. However, LAE occurs in certain pathological conditions and it might represent a diagnostic challenge in athletes. LA volume index (LAVi) by echo is a convenient diagnostic tool for LAE identification. We hypothesized that accumulated lifetime training thousand hours (LTH) would have a main role in LAE. Therefore, our aim was to assess the association between LTH, LAVi and LAE in athletes. Young and middle-aged males with different training levels were included and grouped as recreational (REa, n = 30), competitive (COa, n = 169) and elite (ELa, n = 80) athletes for LTH calculation and echo assessment. LA dimensions resulted greater in ELa when compared to other groups (p < 0.001). LAVi correlated stronger with LTH than with age (p < 0.001). Polynomial regression analysis showed a non-linear, almost triphasic, effect of cumulative training on LA size (p < 0.02). Multivariate logistic regression, including LTH, age, body surface area, systolic blood pressure and other explanatory variables to predict LAE, showed LTH as the sole significant factor [OR 1.45 (CI 1.1-1.92), p < 0.008]. ROC analysis found an optimal cut off point of 3.6 LTH for LAE identification (AUC = 0.84, p < 0.001. RR = 5.65, p < 0.001). We conclude that LAE associates with LTH more than with other clinical parameters, and with less impact at higher amounts of LTH. Lifetime training greater than 3600 hours increases the probability of finding LAE in athletes. Future research should provide more insights and implications of these findings.

Global epidemiology of atrial fibrillation: An increasing epidemic and public health challenge

Background

Atrial fibrillation is the most frequent cardiac arrhythmia. It has been estimated that 6–12 million people worldwide will suffer this condition in the US by 2050 and 17.9 million people in Europe by 2060. Atrial fibrillation is a major risk factor for ischemic stroke and provokes important economic burden along with significant morbidity and mortality.

Aim

We provide here comprehensive and updated statistics on worldwide epidemiology of atrial fibrillation.

Methods

An electronic search was conducted for atrial fibrillation. The epidemiologic information was retrieved from the Global Health Data Exchange database, which is regarded as one of the most comprehensive worldwide catalogs of surveys, censuses, vital statistics, and other health-related data.

Results

A total of 3.046 million new cases of atrial fibrillation worldwide were registered in the database during 2017. The estimated incidence rate for 2017 (403/millions inhabitants) was 31% higher than the corresponding incidence in 1997. The worldwide prevalence of atrial fibrillation is 37,574 million cases (0.51% of worldwide population), increased also by 33% during the last 20 years. The highest burden is seen in countries with high socio-demographic index, though the largest recent increased occurred in middle socio-demographic index countries. Future projections suggest that absolute atrial fibrillation burden may increase by >60% in 2050.

Conclusions

Our analyses suggest that atrial fibrillation incidence and prevalence have increased over the last 20 years and will continue to increase over the next 30 years, especially in countries with middle socio-demographic index, becoming one of the largest epidemics and public health challenges.

Aging and Physiological Lessons from Master Athletes

Sedentary aging is often characterized by physical dysfunction and chronic degenerative diseases. In contrast, masters athletes demonstrate markedly greater physiological function and more favorable levels of risk factors for cardiovascular disease, osteoporosis, frailty, and cognitive dysfunction than their sedentary counterparts. In many cases, age-related deteriorations of physiological functions as well as elevations in risk factors that are typically observed in sedentary adults are substantially attenuated or even absent in masters athletes. Older masters athletes possess greater functional capacity at any given age than their sedentary peers. Impressive profiles of older athletes provide insight into what is possible in human aging and place aging back into the domain of "physiology" rather than under the jurisdiction of "clinical medicine." In addition, these exceptional aging athletes can serve as a role model for the promotion of physical activity at all ages. The study of masters athletes has provided useful insight into the positive example of successful aging. To further establish and propagate masters athletics as a role model for our aging society, future research and action are needed. © 2020 American Physiological Society. Compr Physiol 10:261-296, 2020.

Incidence of Atrial Fibrillation in Elite Athletes

Importance

Vigorous exercise (particularly endurance sports) might increase the risk of atrial fibrillation (AF), but there is variability in the reported frequency of this condition among elite athletes. The underlying pathophysiologic source remains unclear.

Objective

To determine AF incidence in a large cohort of elite athletes and its association with potential risk factors.

Design, Setting, and Participants

Retrospective observational cohort of all Spanish athletes (N = 6813) referred to a single center was used to determine AF incidence from January 1, 1997, to December 31, 2017, and cross-sectional analysis was conducted to compare athletes with and without reported AF. The cohort covered most sports disciplines, and the studied athletes were on national teams and competed in major international events. Cardiologists responsible for echocardiographic assessment were not blinded to the condition (AF or no AF) of the athletes.

Exposures

All participants underwent at least 1 cardiologic evaluation, including assessment at time of AF diagnosis in those with this condition.

Main Outcomes and Measures

Diagnosis of AF based on resting and/or exercise electrocardiogram, and/or 24-hour Holter monitoring and echocardiography-assessed atrial dimensions.

Results

A total of 6813 Spanish elite athletes (2385 [35.0%] women) were referred for cardiac evaluation during the study period. Mean (SD) age was 22 (7) years, and mean (SD) time of competition was 8 (5) years. Only 21 athletes (1 woman), participating in different types of sports, had AF (ie, paroxysmal [n = 18], persistent [n = 1], or long-standing persistent [n = 2]) during the 20-year study. In multivariate analysis, increasing values of age (odds ratio [OR], 1.07; 95% CI, 1.00-1.14), years of competition (OR, 1.14; 95% CI, 1.07-1.22), and left atrial anteroposterior diameter (OR, 1.21; 95% CI, 1.10-1.32) were associated with higher AF risk.

Conclusions and Relevance

The incidence of AF is low among young Spanish elite athletes, even when considering only endurance athletes. Yet, potential contributors (particularly atrial remodeling) need to be monitored.

Supraventricular Arrhythmias in Athletes: Basic Mechanisms and New Directions

Athletes are prone to supraventricular rhythm disturbances including sinus bradycardia, heart block, and atrial fibrillation. Mechanistically, this is attributed to high vagal tone and cardiac electrical and structural remodeling. Here, we consider the supporting evidence for these three pro-arrhythmic mechanisms in athletic human cohorts and animal models, featuring current controversies, emerging data, and future directions of relevance to the translational research agenda.

Can men with atrial fibrillation really rest easy with a CHA2DS2-VASc score of 0?

Background

Atrial fibrillation (AF) significantly increases the risk of ischemic stroke depending on various risk factors. The CHA₂DS₂-VASc score is used widely to improve stratification of AF-related stroke to identify for whom anticoagulation could be safely withheld. As upstream therapy, the management of lifestyle for AF and related stroke prevention has been ongoing for past decades.

Case presentation

A 56-year-old male was taken to our hospital because of acute ischemic stroke. Without intracranial vascular malformation and angiostenosis, two small emboli were successfully taken out from the left middle cerebral artery by mechanical thrombectomy. During the hospitalisation, no apparent abnormalities were found in various laboratory tests, echocardiogram or the coronary computed tomography angiography. However, asymptomatic paroxysmal AF was first diagnosed and was presumed to be responsible for his stroke. Noticeable, he was always in good fitness benefiting from the formed good habits of no smoking and drinking. With a CHA₂DS₂-VASc score of 0, he had no history of any known diseases or risk factors associated with AF and related stroke. Instead of lacking exercise, he persisted in playing table tennis faithfully 3–4 times a week and 2–3 h each time over the past 30 years, and, in fact, has won several amateur table tennis championships.

Conclusion

In view of the possible pathophysiological mechanisms resulting from the long-term vigorous endurance exercise, it may be a potential risk factor for developing AF and even for subsequent stroke. Not merely should strengthen the screening for AF in specific individuals as sports enthusiasts, but the necessity of oral anticoagulant for those with a CHA₂DS₂-VASc score of 0 might deserve the further investigation.

Electronic supplementary material

The online version of this article (10.1186/s12872-019-1150-z) contains supplementary material, which is available to authorized users.

An Assessment of Training Characteristics Associated with Atrial Fibrillation in Masters Runners

A growing body of literature supports an association between long-term endurance exercise and the development of atrial fibrillation (AF). Given the benefits of lifelong exercise, a better understanding of this association is critical to allow healthcare providers to counsel aging exercisers on the proper “dose” of exercise to maximize health benefits but minimize AF risk. The current study examines the relationship between specific aspects of training volume and intensity and the occurrence of AF among older runners in order to better understand what aspects of endurance exercise may contribute to the development of AF. The study was an Internet-based survey of endurance training and health characteristics of runners 35 years of age and older. A total 2819 runners participated and 69 (2.4%) reported a current or prior diagnosis of AF. Among “traditional” risk factors, runners reporting AF were older, more likely to be male, and had higher rates of hypertension and diabetes. Among training characteristics, only accumulated years of training was associated with AF. In contrast, average weekly mileage, training pace, and days of training per week were not associated with AF. In a multivariable analysis that included chronologic age, sex, diabetes, and hypertension, accumulated years of training remained significantly associated with the report of AF. These findings suggest that the relationship between chronic endurance exercise and AF is dependent on the accumulated training duration but does not appear to be influenced by specific training characteristics such as frequency or intensity of endurance exercise. Further confirmation of these relationships may help healthcare providers counsel exercisers on optimal training habits and identify endurance athletes who are at risk for the development of AF.

Effectiveness and safety of electrical cardioversion for acute-onset atrial fibrillation in the emergency department: a real-world 10-year single center experience

OBJECTIVE

Despite limited evidence, electrical cardioversion of acute-onset atrial fibrillation (AAF) is widely performed in the emergency department (ED). The aim of this study was to describe the effectiveness and safety of electrical cardioversion of AAF performed by emergency physicians in the ED.

METHODS

All episodes of AAF electrically cardioverted in the ED were retrieved from the database for a 10-year period. Most patients not already receiving anticoagulants were given enoxaparin before the procedure (259/419). Procedural complications were recorded, and the patients were followed-up for 30 days for cardiovascular and hemorrhagic complications.

RESULTS

Four hundred nineteen eligible cases were identified; men represented 69%, and mean age was 61±13 years. The procedure was effective in 403 cases (96.2%; 95.4% in women, 96.5% in men), with considerable differences with respect to the age of the patients, the procedure being effective in 100% of patients aged 18 to 39 and only 68.8% in those >80 years. New ED visits (33/419) were identified within 30 days (31 due to atrial fibrillation/atrial flutter recurrence, 1 due to iatrogenic hypokalemia, 1 due to hypertensive emergency). No strokes, major bleeding, life-threatening arrhythmias or peripheral thromboembolism were recorded. Nine small and mild skin burns were observed.

CONCLUSION

Electrical cardioversion is an effective and safe procedure in the vast majority of patients, albeit less effective in patients aged >80 years. It appears reasonable to avoid anticoagulation in low-risk patients with AAF and administer peri-procedural heparin to all remaining patients. Long-term anticoagulation should be planned on an individual basis, after assessment of thromboembolic and hemorrhagic risk.

Competitive Endurance Activities of Middle-aged Athletes as a Risk Factor for Atrial Fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia in athletes. Epidemiological studies have documented a greater prevalence of AF in athletes engaged in long-term endurance sports. Several mechanisms were proposed to underlie the association between exercise and AF, but the exact pathophysiology remains unclear. The studies up to now have been concentrated on the competitive middle-aged endurance athletes, but there is no evidence of AF prevalence among highly active noncompetitive athletes of the same age. Endurance athletes who do not compete might be at a lower risk for AF than their competitive peers. This hypothesis is theoretically examined, and the current evidence summarized in this article.

Excessive exercise in endurance athletes: Is atrial fibrillation a possible consequence?

Moderate physical activity levels are associated with increased longevity and lower risk of atrial fibrillation (AF). However, the relative risk of lone AF is 3-5-fold higher in intensive endurance-trained athletes compared with healthy adults. There is growing concern that "excessive" endurance exercise may promote cardiac remodelling, leading to long-term adverse consequences. The pathogenesis of exercise-induced AF is thought to arise from an interplay of multiple acute and chronic factors, including atrial enlargement, pro-fibrotic tendency, high vagal tone, and genotypic profile, which collectively promote adverse atrial remodelling. Clinical management of athletes with AF, while challenging, can be achieved using various strategies that may allow continued, safe exercise. Based on the overall risk-benefit evidence, it is premature to suggest that excessive exercise is unsafe or should be curtailed. Evidence-based assessment and treatment guidelines are required to ensure optimal and safe exercise among the growing number of endurance athletes with AF.

Associations of Fitness, Physical Activity, Strength, and Genetic Risk With Cardiovascular Disease: Longitudinal Analyses in the UK Biobank Study

BACKGROUND

Observational studies have shown inverse associations among fitness, physical activity, and cardiovascular disease. However, little is known about these associations in individuals with elevated genetic susceptibility for these diseases.

METHODS

We estimated associations of grip strength, objective and subjective physical activity, and cardiorespiratory fitness with cardiovascular events and all-cause death in a large cohort of 502 635 individuals from the UK Biobank (median follow-up, 6.1 years; interquartile range, 5.4-6.8 years). Then we further examined these associations in individuals with different genetic burden by stratifying individuals based on their genetic risk scores for coronary heart disease and atrial fibrillation. We compared disease risk among individuals in different tertiles of fitness, physical activity, and genetic risk using lowest tertiles as reference.

RESULTS

Grip strength, physical activity, and cardiorespiratory fitness showed inverse associations with incident cardiovascular events (coronary heart disease: hazard ratio [HR], 0.79; 95% confidence interval [CI], 0.77-0.81; HR, 0.95; 95% CI, 0.93-0.97; and HR, 0.68; 95% CI, 0.63-0.74, per SD change, respectively; atrial fibrillation: HR, 0.75; 95% CI, 0.73-0.76; HR, 0.93; 95% CI, 0.91-0.95; and HR, 0.60; 95% CI, 0.56-0.65, per SD change, respectively). Higher grip strength and cardiorespiratory fitness were associated with lower risk of incident coronary heart disease and atrial fibrillation in each genetic risk score group (P_trend <0.001 in each genetic risk category). In particular, high levels of cardiorespiratory fitness were associated with 49% lower risk for coronary heart disease (HR, 0.51; 95% CI, 0.38-0.69) and 60% lower risk for atrial fibrillation (HR, 0.40; 95%, CI 0.30-0.55) among individuals at high genetic risk for these diseases.

CONCLUSIONS

Fitness and physical activity demonstrated inverse associations with incident cardiovascular disease in the general population, as well as in individuals with elevated genetic risk for these diseases.