Atrial fibrillation, physical activity and endurance training

Atrial Fibrillation in Athletes-Features of Development, Current Approaches to the Treatment, and Prevention of Complications

Atrial fibrillation (AF) is one of the most common types of cardiac arrhythmias. This review article highlights the problem of the development of atrial fibrillation in individuals engaged in physical activity and sports. Predisposing factors, causes, and development mechanisms of atrial fibrillation in athletes from the perspective of the authors are described. Methods of treatment, as well as prevention of thromboembolic complications, are discussed. Directions for further studies of this problem and prevention of complications are proposed.

Physical Activity and Risk of Atrial Fibrillation: A Nationwide Cohort Study in General Population

Although exercise prevents cardiovascular disease and mortality, vigorous exercise and endurance athletics can cause atrial fibrillation (AF). However, no large cohort study has assessed the relationship between physical activity and AF in the general population. We assessed the effect of physical activity at different energy expenditures on the incidence of AF. We studied 501,690 individuals without pre-existing AF (mean age, 47.6 ± 14.3 years; 250,664 women [50.0%]) included in the Korean National Health Insurance Service database. The physical activity level was assessed using a standardized self-reported questionnaire at baseline. During a median follow-up of 4 years, 3,443 participants (1,432 women [41.6%]) developed AF. The overall incidence of AF at follow-up was 1.79 per 1,000 person-years. The subjects who met the recommended physical activity level (500–1,000 metabolic equivalent task [MET] minutes/week) had a 12% decreased AF risk (adjusted hazard ratio [HR]: 0.88, 95% confidence interval [CI]: 0.80–0.97), but not the insufficiently (1–500 MET-minutes/week; HR: 0.94, 95% CI: 0.86–1.03) and highly active subjects (≥1,000 MET-minutes/week; HR: 0.93, 95% CI: 0.85–1.03). The recommended minimum key target range of physical activity level was associated with the maximum benefit for reduced AF risk in the general population. The dose-response relationship between physical activity level and AF risk showed a U-shaped pattern. Although exceeding the key target range attenuated this benefit, it did not increase the AF risk beyond that during inactivity.

Resting Heart Rate and the Risk of Atrial Fibrillation

In a previous meta-analysis, it was demonstrated that the resting heart rate (RHR) is a potential risk factor for atrial fibrillation (AF). However, the results of that meta-analysis were conflicting, and the relationship between the RHR and AF is still not well established. In the current meta-analysis, our aim is to update evidence with a better statistical model. We searched the Cochrane Library, PubMed, and Embase databases for relevant studies and used a "one-stage approach" with a restricted cubic spline model to summarize the dose-specific relationships between the RHR and AF. Relative risk (RR) was used to measure the effects. In total, 10 studies were included, with a total of 18,630 cases of AF among 431,432 participants. In the dose-response analysis, there was evidence of a nonlinear association between the RHR and the risk of AF (nonlinearity, P < 0.0001), which exhibited a significant J-shaped association between the two factors. An RHR between 68 and 80 bpm had the lowest risk of AF. Among people who had RHR < 70 bpm, the summary RR was 1.09 per 10-RHR decrease (95% confidence interval [CI] = 1.06-1.12; P < 0.001). The results were similar for participants with RHR > 70 bpm (per 10 bpm increase) (RR = 1.06, 95% CI = 1.03-1.08; P < 0.001). Our dose-response meta-analysis revealed a significant J-shaped association between the RHR and AF. Both low RHR and high RHR were associated with an increased risk of AF compared with a modest RHR of 68-80 bpm.

[Descriptive and comparative study of cardiovascular risk factors and physical activity in patients with acute coronary syndrome]

Objetivo

Analizar diversos factores de riesgo cardiovascular en función de la actividad física realizada en pacientes con síndrome coronario agudo (SCA).

Diseño

Estudio observacional transversal.

Emplazamiento

Servicio de prevención cardiovascular hospitalario (Departamento Salud, Valencia, España).

Participantes

Un total de 401 sujetos con SCA y alta hospitalaria entre 2 y 3 meses previos a la medición, entre 30 y 80 años; ausencia de contraindicación para realizar actividad física; sin participación previa en programas de rehabilitación cardiaca.

Mediciones principales

Se estimó el equivalente metabólico MET (kcal/kg) según el tipo de actividad, frecuencia, duración e intensidad. La muestra se dividió en 2 grupos: grupo sedentario (consumo < 10 MET/semana) y grupo físicamente activo (≥ 10 MET/semana). Se analizaron diversas variables relacionadas con los factores de riesgo cardiovascular: índice de masa corporal (IMC), perímetro abdominal, perfil lipídico, glucemia y presión arterial.

Resultados

La actividad física general registró un consumo medio de 8,24 ± 12,5 MET/semana. Los factores prevalentes fueron sobrepeso (77,05%) y dislipemia (64,3%). El 64,8% refirió sedentarismo. El grupo físicamente activo mostró diferencias significativas en relación al grupo no activo en los niveles de triglicéridos (146,53 ± 72,8 vs. 166,94 ± 104,78 mg/dl; IC 95%; p = 0,031) y el IMC (27,65 ± 3,86 vs. 28,50 ± 4,38 kg/m²; IC 95%; p = 0,045).

Conclusión

Los pacientes con SCA realizaron escasa actividad física, con prevalencia de sobrepeso y dislipemia. Los sujetos físicamente activos mejoraron los niveles de triglicéridos y el índice de masa corporal. Desde atención primaria es necesaria la promoción de la salud mediante el fomento de ejercicio en pacientes con SCA.

Sex Differences in the Association Between Regular Physical Activity and Incident Atrial Fibrillation: A Meta-analysis of 13 Prospective Studies

Several studies investigated the role of physical activity in atrial fibrillation (AF), but the results remain controversial. We aimed to estimate the association between physical activity and incident AF, as well as to determine whether a sex difference existed. We systematically retrieved relevant studies from Cochrane Library, PubMed, and ScienceDirect through December 1, 2015. Data were abstracted from eligible studies and effect estimates pooled using a random-effects model. Thirteen prospective studies fulfilled inclusion criteria. For primary analysis, neither total physical activity exposure (relative risk [RR]: 0.98, 95% confidence interval [CI]: 0.90-1.06, P = 0.62) nor intensive physical activity (RR: 1.07, 95% CI: 0.93-1.25, P = 0.41) was associated with a significant increased risk of AF. In the country-stratified analysis, the pooled results were not significantly changed. However, in the sex-stratified analysis, total physical activity exposure was associated with an increased risk of AF in men (RR: 1.18, 95% CI: 1.02-1.37), especially at age <50 years (RR: 1.58, 95% CI: 1.28-1.95), with a significantly reduced risk of AF in women (RR: 0.92, 95% CI: 0.87-0.97). Additionally, male individuals with intensive physical activity had a slightly higher (although statistically nonsignificant) risk of developing AF (RR: 1.12, 95% CI: 0.99-1.28), but there was a significantly reduced risk of incident AF in women (RR: 0.92, 95% CI: 0.86-0.98). Published literature supports a sex difference in the association between physical activity and incident AF. Increasing physical activity is probably associated with an increased risk of AF in men and a decreased risk in women.

Physical activity, resting heart rate, and atrial fibrillation: the Tromsø Study

AIMS

The objective was to examine the association of physical activity and resting heart rate (RHR) with hospital-diagnosed atrial fibrillation (AF) in a Norwegian cohort.

METHODS AND RESULTS

This prospective study included 20 484 adults (50.3% men) who participated in the third Tromsø Study survey in 1986-87. At baseline, physical activity was assessed by a validated questionnaire, and RHR was objectively measured. Participants were followed from baseline through 2010 with respect to incident cases of hospital-diagnosed AF documented on an electrocardiogram. During a mean follow-up period of 20 years (409 045 person-years), 750 participants (70.5% men) were diagnosed with AF. Compared with the low physical activity group, moderately active individuals had a 19% lower risk of any AF [adjusted hazard ratio (HR) 0.81, 95% confidence interval (CI) 0.68-0.97], whereas highly active had similar risk of AF. Vigorously active individuals showed a non-significantly higher risk of AF (adjusted HR 1.37, 95% CI 0.77-2.43). Risk of AF increased with decreasing RHR (adjusted HR 0.92, 95% CI 0.86-0.98 for each 10 b.p.m. increase in RHR), and RHR < 50 b.p.m. was a risk factor for AF (P < 0.05).

CONCLUSION

In this prospective cohort study, leisure time physical activity was associated with AF in a J-shaped pattern. Moderate physical activity was associated with a reduced risk of AF, whereas higher activity levels attenuated the benefits of moderate activity. Low RHR was a risk factor for AF. Our results support the hypothesis that moderate and vigorous physical activity may affect AF risk via different pathophysiological mechanisms.

[Atrial fibrillation and physical activity. An overview]

A training-induced increase in vagal tone, left atrial enlargement and high atrial volume load due to exercise can theoretically favor induction and continuation of atrial fibrillation (AF) in (endurance) athletes. However, there is currently no evidence for a higher occurrence of AF in young endurance athletes in comparison to an age-matched normal population. The correlate of long-term endurance training results in proarrhythmogenic atrial remodeling in a rat model. The results of some studies also suggest that there may be atrial remodeling in humans, which might be an explanation for the comparatively higher incidence of AF in veteran athletes, whereby the relative risk might have been overestimated due to methodological problems, e.g. due to insufficient consideration of "new" AF risk factors. To date, there are no indications for an increased risk of AF due to normal physical activity: on the contrary, moderate physical activity seems to decrease the risk for AF. For an individual evaluation of sports participation of patients with AF, the overall cardiac situation, atrioventricular conduction during exercise, a possible oral anticoagulation as well as the sport and training intensity practiced are important. Well-adapted training for patients with AF has to be considered as safe and effective in terms of the overall positive effects of physical activity in patients with cardiovascular problems, for example due to a positive influence on cardiovascular risk factors.

Effect of years of endurance exercise on risk of atrial fibrillation and atrial flutter

Emerging evidence suggests that endurance exercise increases the risk for atrial fibrillation (AF) in men, but few studies have investigated the dose-response relation between exercise and risk for atrial arrhythmias. Both exposure to exercise and reference points vary among studies, and previous studies have not differentiated between AF and atrial flutter. The aim of this study was to assess the risk for atrial arrhythmias by cumulative years of regular endurance exercise in men. To cover the range from physical inactivity to long-term endurance exercise, the study sample in this retrospective cohort study was based on 2 distinct cohorts: male participants in a long-distance cross-country ski race and men from the general population, in total 3,545 men aged ≥ 53 years. Arrhythmia diagnoses were validated by electrocardiograms during review of medical records. Regular endurance exercise was self-reported by questionnaire. A broad range of confounding factors was available for adjustment. The adjusted odds ratios per 10 years of regular endurance exercise were 1.16 (95% confidence interval 1.06 to 1.29) for AF and 1.42 (95% confidence interval 1.20 to 1.69) for atrial flutter. In stratified analyses, the associations were significant in cross-country skiers and in men from the general population. In conclusion, cumulative years of regular endurance exercise were associated with a gradually increased risk for AF and atrial flutter.

Increased risk of atrial fibrillation among elderly Norwegian men with a history of long-term endurance sport practice

Atrial fibrillation (AF) is the most common cardiac arrhythmia. The prevalence increases with increasing age. In middle-aged men, endurance sport practice is associated with increased risk of AF but there are few studies among elderly people. The aim of this study was to investigate the role of long-term endurance sport practice as a risk factor for AF in elderly men. A cross-sectional study compared 509 men aged 65-90 years who participated in a long-distance cross-country ski race with 1768 men aged 65-87 years from the general population. Long-term endurance sport practice was the main exposure. Self-reported AF and covariates were assessed by questionnaires. Risk differences (RDs) for AF were estimated by using a linear regression model. After multivariable adjustment, a history of endurance sport practice gave an added risk for AF of 6.0 percent points (pp) (95% confidence interval 0.8-11.1). Light and moderate leisure-time physical activity during the last 12 months reduced the risk with 3.7 and 4.3 pp, respectively, but the RDs were not statistically significant. This study suggests that elderly men with a history of long-term endurance sport practice have an increased risk of AF compared with elderly men in the general population.

Economic evaluation of warfarin, dabigatran, rivaroxaban, and apixaban for stroke prevention in atrial fibrillation

BACKGROUND

Atrial fibrillation is a major risk factor for stroke, which causes thousands of deaths and sequelae. It is recommended that atrial fibrillation patients at medium or high risk of stroke use an oral anticoagulant to reduce the risk of stroke. In the past few years, three new oral anticoagulants (NOACs), dabigatran, rivaroxaban, and apixaban, have been introduced in competition to the older oral anticoagulant warfarin.

OBJECTIVE

The objective of this study was to evaluate the relative cost effectiveness of warfarin, dabigatran, rivaroxaban, and apixaban in a Norwegian setting.

METHODS

We created a probabilistic decision-analytic Markov model to simulate the life of patients with atrial fibrillation. We performed several scenario analyses, including changing the switching age for dabigatran from 80 to 75 years old.

RESULTS

Assuming the European Society of Cardiology guidance, sequential dabigatran (2 × 150 mg daily until 80 years old, 2 × 110 mg thereafter) seems to be the most cost-effective alternative for high-risk AF patients. For medium-risk patients, apixaban (2 × 5 mg daily) seems to be somewhat more effective than dabigatran, but dabigatran is still marginally the most cost-effective alternative. In scenario analyses reducing dabigatran from 2 × 150 mg to 2 × 110 mg at the age of 75 years (instead of at age 80), apixaban (2 × 5 mg daily) becomes the most cost-effective alternative for both risk groups.

CONCLUSION

We have found apixaban or sequential dabigatran to be the alternatives most likely to be considered cost effective, depending on the switching age for dabigatran. These conclusions are highly sensitive to assumptions made in the analysis.

[Atrial fibrillation and physical activity]

Atrial fibrillation is the most frequent arrhythmia. Its "lone" form (when underlying pathology is not discovered) can be detected in a small percentage of endurance sports participants, and in growing numbers among veterans, probably as a result of some cardiac or other irregularities. Enhanced vagal tone and sudden sympathetic impulse, repetitive oxidative stress, inflammatory processes, enlarged atria, electric instabilization can explain the higher occurrence. Treatment of atrial fibrillation enables the affected persons to participate in regular medium-intensity exercise, 3-5 hours a week, which offers a protective role against cardiovascular, metabolic and mental illnesses.