Atrial fibrillation in endurance athletes

Advances in Atrial Fibrillation Management: A Guide for General Internists

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, impacting approximately 6.1 million adults in the United States, with projections to increase two-fold by 2030. AF significantly increases the risk of stroke and other adverse cardiovascular events, leading to increased morbidity and mortality. The 2023 ACC/AHA/ACCP/HRS guidelines present a paradigm shift in AF management, moving from a duration-based classification to a more comprehensive, patient-centered approach. This includes a novel AF classification system that emphasizes early detection and intervention, including risk factors and lifestyle modification tailored to each patient's risk profile. Moreover, the recommendations advocate for a multidisciplinary care model, ensuring coordinated management involving primary care providers and specialists. Primary care providers play a crucial role in initiating risk factor management and lifestyle interventions, even before the development of AF. This review aims to thoroughly examine the guidelines for the diagnosis and management of AF and equip general internists with the necessary insights to navigate the evolving landscape of AF care effectively.

Echocardiography in the Assessment of Heart Failure Patients

Doppler echocardiography is the corner-stone of non-invasive investigation of patients with a clinical diagnosis of heart failure. It provides an accurate and quantitative assessment of cardiac structure and function. Furthermore, spectral Doppler measurement is an invaluable technique for estimating intracardiac pressures with their crucial value in the optimum management of heart failure patients, irrespective of ejection fraction. Speckle tracking echocardiography stretches the unique application of echocardiography to analyze the myocardial deformation function which has proved very accurate in detecting ischemia, dyssynchrony, subclinical dysfunction and also in estimating pulmonary capillary wedge pressures. The role of longitudinal myocardial left atrial deformation dynamics has recently emerged as a valuable tool for assessing left ventricular diastolic dysfunction in patients with cardiac diseases regardless of their ejection fraction. Finally, the extent of myocardial deformation has been shown to correlate with the severity of myocardial fibrosis, a common finding in patients with heart failure.

Impact of atrial fibrillation and atrial fibrillation therapies on sports performance in athletes

BACKGROUND

It has been hypothesized that both atrial fibrillation (AF) and medications for AF are poorly tolerated in athletes.

OBJECTIVE

The purpose of this study was to determine the impact of AF and AF treatments on sports performance.

METHODS

An Internet-based survey, initiated via StopAfib.org, queried the impact of AF and treatment modalities on sports performance, training, and symptoms. Performance (rated in comparison to personal best), frequency of training, and competition were compared before onset of AF symptoms vs when symptoms at worst, via paired Wilcoxon, and then similarly compared in relation to participants' AF treatments.

RESULTS

Between May 13, 2019, and February 29, 2020, 1055 athletes responded (78% male, median age 61-70 years). The sports most reported were cycling (25%) and running (20%). Development of AF was associated with declining sports performance, competition, and training frequency. Of 565 participants who detrained, 31% reported no change in symptoms, 56% reported decreased frequency, and 13% reported no further AF. Among athletes who received treatment, ablation was associated with greater improvement in sports performance than use of medications. Of 262 athletes currently taking medication, 27% reported that it was completely effective, 58% partially effective, and 15% not effective. Of 653 athletes who have taken medication currently and/or in the past, 43% reported side effects, most commonly fatigue, low energy, or decreased athletic performance.

CONCLUSION

Athletes reported that AF was associated with worsening sports performance. Among AF treatment modalities, ablation was associated with the greater reported improvement in sports performance than use of medications, which also had a high frequency of side effects.

Diastolic function and dysfunction in athletes

Cardiac remodelling is often most profound in male athletes and in athletes with the greatest volumes of endurance training and is characterized by chamber enlargement and a mild-to-modest hypertrophy. The diastolic filling of the left ventricle (LV) is a complex process including the early recoil of the contracted LV, the active relaxation of the myocardium, the compliance of the myocardium, the filling pressures, and heart rate. Echocardiography is the cornerstone for the clinical assessment of LV diastolic function. LV diastolic function is usually enhanced in elite endurance athletes characterized by improved early filling of the ventricle, while it is preserved or enhanced in other athletes associated with the type of training being performed. This allows for the high performance of any endurance athlete. Typical findings when using resting echocardiography for the assessment of LV diastolic function in endurance athletes include a dilated LV with normal or mildly reduced LV ejection fraction (EF), significantly enlarged left atrium (LA) beyond the commonly used cut-off of 34 mL/m2, and a significantly elevated E/A ratio. The early-diastolic mitral annular velocity and the E-wave peak velocity are usually normal. Importantly, interpretation of the echocardiographic indices of LV diastolic function should always consider the clinical context and other parameters of systolic and diastolic functions. In the absence of an underlying pathology, single measurements outside the expected range for similar athletes will often not represent the pathology.

Exaggerated Blood Pressure Response to Exercise Is a Risk of Future Hypertension Even in Healthy, Normotensive Young Individuals-Potential Preventive Strategies for This Phenomenon?

Physical activity and regular exercise are well known to reduce the risks of cerebrovascular and cardiovascular diseases, leading the American College of Sports Medicine to endorse the concept that "exercise is medicine". However, a single bout of exercise temporarily raises arterial blood pressure (BP) to meet the metabolic demands of working muscle, and this BP response is particularly exaggerated in older adults and patients with cardiovascular conditions, such as hypertension, resulting in an exaggerated BP response during exercise. This presents a paradox: while regular exercise is crucial for preventing these diseases, excessively high BP responses during exercise could increase the risk of vascular damage. The mechanisms underlying this exaggerated BP response during exercise remain unclear, and effective exercise regimens for these populations have yet to be established. Currently, low-intensity exercise is recommended; however, its efficacy in disease prevention is uncertain. Notably, even among healthy individuals, there is significant variation in the BP response to exercise. Some healthy individuals, despite having normal resting BP, exhibit an exaggerated BP response during physical activity. Importantly, these individuals are often unaware that their BP becomes excessively elevated during physical activity. Repeated exposure to these heightened BP responses through regular physical activity may increase their long-term risk of cardiovascular disease. How can we prevent disease development in these individuals while still ensuring the effectiveness of exercise? Some studies have shown that individuals with a family history of hypertension may experience this phenomenon even in children and adolescents. Additionally, left ventricular hypertrophy contributes to an exaggerated BP response to exercise, suggesting a possible genetic influence. Conversely, other reports indicate that factors such as arterial stiffness, obesity, and low exercise capacity also contribute to this exaggerated response. Our recent preliminary data suggest that the cognitive benefits of exercise may be diminished in individuals who exhibit an exaggerated BP response during exercise. This implies that individuals with an exaggerated BP response, despite having normal resting BP, may not fully benefit from exercise. In this perspective paper, we review the physiological aspects of this phenomenon and explore strategies to address it. Additionally, we discuss BP responses in athletes within this content. Our goal is to prevent disease while maximizing the benefits of exercise for healthy individuals with an exaggerated BP response, as well as for elderly and cardiovascular patients.

Determinants of supraventricular extra beats in elite athletes practicing different sporting disciplines

BACKGROUND

Supraventricular extra beats (SVEB) are frequently observed in athletes but data on significance, prognostic role and correlation with cardiac remodeling are contrasting. It is uncertain whether SVEB may indicate the development of more complex arrhythmias and the need for closer monitoring is undetermined. The aim was to assess the prevalence and clinical significance of BESV in Olympic athletes of different sporting disciplines, evaluating potential correlations with cardiac remodeling and clinical features.

METHODS

We enrolled athletes who participated at 2012-2022 Olympic Games, submitted to physical examination, blood tests, echocardiography and exercise tests, categorized into power, skills, endurance and mixed disciplines.

RESULTS

We studied 1492 elite athletes: 56% male individuals, mean age 25.8 ± 5.1 years; 29.5% practiced power, 12.3% skills, 21% endurance and 37.2% mixed disciplines. At exercise-stress tests, 6.2% had SVEB, mostly single beats. SVEB were not influenced by anthropometrics or blood test results. They were more common in male individuals (77.4 vs. 54.6%, P < 0.0001) and older athletes (27.1 ± 5.7 vs. 25.7 ± 5.1, P = 0.01). In male athletes with SVEB, higher left atrial volumes were observed (24.2 ± 7.3 vs. 22.2 ± 7.1 ml/m2, P = 0.03). No differences were found in terms of sporting discipline: despite larger left atrial dimensions in aerobic disciplines, SVEB rates were similar in different sporting disciplines (6.1% endurance, 6.3% mixed, 5.2% power and 8.7% skills; P = 0.435).

CONCLUSION

SVEB were more common in older, male athletes and associated with higher left atrial volume (especially in male individuals) regardless of sport practiced. Athletes with greater left atrial volume and SVEB are supposed to have higher risk, in middle age, of developing more complex arrhythmias.

When the Clock Strikes A-fib

Within the broad spectrum of atrial fibrillation (AF) symptomatology, there is a striking subset of patients with predominant or even solitary nocturnal onset of the arrhythmia. This review covers AF with nocturnal onset, with the aim of defining this distinctive subgroup among patients with AF. A periodicity analysis is provided showing a clear increased onset between 10:00 pm and 7:00 am. Multiple interacting mechanisms are discussed, such as circadian modulation of electrophysiological properties, vagal tone, and sleep disorders, as well as the potential interaction and synergism between these factors, to provide a better understanding of this clinical entity. Lastly, potential therapeutic targets for AF with nocturnal onset are addressed such as upstream therapy for underlying comorbidities, type of drug and timing of drug administration and pulmonary vein isolation, ablation of the ganglionated plexus, and autonomic nervous system modulation. Understanding the underlying AF mechanisms in the individual patient with nocturnal onset will contribute to patient-specific therapy.

Possible Mechanisms for Adverse Cardiac Events Caused by Exercise-Induced Hypertension in Long-Distance Middle-Aged Runners: A Review

Sudden cardiac death (SCD) is rare among athletes. However, hypertrophic cardiomyopathy is the leading cause of SCD among those <35 years of age. Meanwhile, coronary artery disease (CAD) is the primary SCD cause among those ≥35 years of age. CAD-induced plaque ruptures are believed to be a significant cause of cardiovascular diseases in middle-aged individuals who participate in extreme long-distance running activities such as marathons. A total of 1970 articles related to EIH were identified using search terms. Out of these, 1946 studies were excluded for reasons such as arterial hypertension, exercise-induced pulmonary hypertension, the absence of exercise stress testing (EST), and a lack of relevance to EIH. The study analyzed 24 studies related to both long-distance runners with exercise-induced hypertension (EIH) and the general public. Among these, 11 studies were quasi-experimentally designed studies used in randomized controlled trials (RCTs) on long-distance runners with EIH. Additionally, 12 studies utilized cohort designs, and one study with a quasi-experimental design was conducted among the general population. Recent studies suggest that an imbalance between oxygen demand and supply due to ventricular hypertrophy may be the actual cause of cardiovascular disease, regardless of CAD. Exercising excessively over an extended period can reduce endothelial function and increase arterial stiffness, which in turn increases afterload and leads to an excessive increase in blood pressure during exercise. Exercise-induced hypertension (EIH), which increases the morbidity rate of resting hypertension and is a risk factor for cardio-cerebro-vascular diseases, is more prevalent in middle-aged long-distance runners than in runners from other age groups, and it increases the prevalence of critical arrhythmias, such as atrial fibrillation or ventricular arrhythmias. EIH is associated with angiotensin II activity, and angiotensin II receptor blockers show promising effects in middle-aged runners. Further, guidelines for preventing excessive participation in races and restricting exercise intensity and frequency would be useful. This review identifies EIH as a potential risk factor for cardiovascular diseases and describes how EIH induces SCD.

Elite female endurance athletes are at increased risk of atrial fibrillation compared to the general population: a matched cohort study

OBJECTIVE

Previous studies have found that endurance sport activity is associated with an increased risk of atrial fibrillation (AF) in men. However, it remains unclear whether endurance sports also influence the risk of AF in women. We aimed to examine whether participation in endurance sports may affect the risk of AF in female athletes.

METHODS

We conducted a retrospective matched cohort study of top Swedish female endurance athletes (n=228) and reference individuals (n=1368) from the general population using the Swedish Total Population Register individually matched with a 6:1 ratio of female athletes. The athlete cohort was created by combining all Swedish women who ran the Stockholm Marathon faster than 3 hours 15 min in any of the races between 1979 and 1991, all women competing in the Swedish athletic national championships in the 10 000 metre race, and the top-ranked Swedish cyclists during the same period. We used the National Patient Register to determine whether the participants were diagnosed with AF.

RESULTS

Mean age at the start of follow-up was 32 (SD±8.5) years. During follow-up (mean 28.8 years; SD±4.4), 33 cases of AF were diagnosed, including 10 (4.4%) among athletes and 23 (1.7%) among references. The HR for female athletes compared with the reference population was 2.56 (95% CI 1.22 to 5.37) in the univariable model and 3.67 (95% CI 1.71 to 7.87) after adjustment for hypertension.

CONCLUSION

Elite female endurance athletes are at increased risk of AF than the general population.

Atrial fibrillation: primary prevention, secondary prevention, and prevention of thromboembolic complications: part 1

Atrial fibrillation (AF), is the most common sustained cardiac arrhythmia. It was once thought to be benign as long as the ventricular rate was controlled, however, AF is associated with significant cardiac morbidity and mortality. Increasing life expectancy driven by improved health care and decreased fertility rates has, in most of the world, resulted in the population aged ≥65 years growing more rapidly than the overall population. As the population ages, projections suggest that the burden of AF may increase more than 60% by 2050. Although considerable progress has been made in the treatment and management of AF, primary prevention, secondary prevention, and prevention of thromboembolic complications remain a work in progress. This narrative review was facilitated by a MEDLINE search to identify peer-reviewed clinical trials, randomized controlled trials, meta-analyses, and other clinically relevant studies. The search was limited to English-language reports published between 1950 and 2021. Atrial fibrillation was searched via the terms primary prevention, hyperthyroidism, Wolff-Parkinson-White syndrome, catheter ablation, surgical ablation, hybrid ablation, stroke prevention, anticoagulation, left atrial occlusion and atrial excision. Google and Google scholar as well as bibliographies of identified articles were reviewed for additional references. In these two manuscripts, we discuss the current strategies available to prevent AF, then compare noninvasive and invasive treatment strategies to diminish AF recurrence. In addition, we examine the pharmacological, percutaneous device and surgical approaches to prevent stroke as well as other types of thromboembolic events.

The AFLETES Study: Atrial Fibrillation in Veteran Athletes and the Risk of Stroke

OBJECTIVES

Endurance athletes are at an increased risk of atrial fibrillation (AF) when compared with the general population. However, the risk of stroke in athletes with AF is unknown.

DESIGN AND SETTING

We aimed to assess this risk using an international online survey.

PATIENTS

Individuals that had competed in ≥1 competitive events and were ≥40 years old were included.

INTERVENTIONS

Self-reported demographic, medical history, and training history data were collected, and a CHA 2 DS 2 -VASc was calculated.

MAIN OUTCOME MEASURES

Binary logistic regression was used to assess variables associated with AF and stroke.

RESULTS

There were 1002 responses from participants in 41 countries across Africa, Asia, Australasia, Europe, and North and South America, and 942 were included in the final analysis. The average age was 52.4 ± 8.5 years, and 84% were male. The most common sports were cycling (n = 677, 72%), running (n = 558, 59%), and triathlon (n = 245, 26%). There were 190 (20%) individuals who reported AF and 26 individuals (3%) who reported stroke; of which, 14 (54%) had AF. Lifetime exercise dose [odds ratio (OR), 1.02, 95% confidence interval (95% CI),1.00-1.03, P = 0.02] and swimming (OR, 1.56, 95% CI, 1.02-2.39, P = 0.04) were associated with AF in multivariable analysis, independent of other risk factors. Atrial fibrillation was associated with stroke (OR, 4.18, 95% CI, 1.80-9.72, P < 0.01), even in individuals with a low (0/1) CHA 2 DS 2 -VASc score (OR, 4.20, 95% CI, 1.83-9.66, P < 0.01).

CONCLUSIONS

This survey provides early evidence that veteran endurance athletes who develop AF may be at an increased risk of developing stroke, even in those deemed to be at low risk by CHA 2 DS 2 -VASc score.

The interplay among body weight, blood pressure, and cardiorespiratory fitness in predicting atrial fibrillation

BACKGROUND

Hypertension, obesity, and low cardiorespiratory fitness (CRF) are known risk predictors for the development of atrial fibrillation (AF) that often interrelate with each other. We examined the interplay of these 3 risk indicators with the occurrence of AF in patients without known cardiovascular disease.

METHODS

A retrospective analysis of 13,042 patients underwent exercise stress testing (EST). The occurrence of AF during the median follow-up period of 6.8 years was investigated in relation to the presence of obesity (body mass index ≥30 kg/m²), hypertension (blood pressure ≥140/90 mmHg or history of hypertension), or low CRF (exercise capacity <8 metabolic equivalents). Cox proportional hazards models were used to evaluate the individual and combined association between the 3 risk indicators and AF.

RESULTS

The mean age of the study population was 58 ± 9 years; 49% were women. AF occurred in 499 patients (3.8%). Obesity [hazard ratio (95% confidence interval)], 1.36 (1.12-1.65), hypertension, 1.47 (1.19-1.82), and low CRF, 1.32 (1.06-1.64), were independent risk predictors for AF after multivariable adjustment, including after adjusting for each other and also when the risk predictors were analyzed as continuous variables. In a combined model, a gradual increase in the risk of AF was observed, reaching an adjusted hazard ratio of 2.53 (1.77-3.62) in those with all 3 compared with neither risk indicators. P-for-interaction between hypertension and obesity, or hypertension and low CRF was nonsignificant.

CONCLUSIONS

Obesity, low CRF, and hypertension are independently associated with an excess risk of developing AF in patients without known cardiovascular disease, both individually and more so when coexisting together.

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.

Characteristics of United States military pilots with atrial fibrillation and deployment and retention rates

Introduction

Atrial fibrillation (AF) is an arrhythmia that impacts deployment and retention rates for United States military pilots. This study aims to characterize United States active duty (AD) pilots with AF and review deployment and retention rates associated with medical and ablative therapies.

Methods

An observational analysis was performed to assess AD pilots diagnosed with AF in the largest military regional healthcare system from 2004 to 2019. Baseline characteristics and AF management were reviewed.

Results

27 AD pilots (mean age, 37.3 ± 7.9 years; mean BMI, 27.3 ± 3.1 kg/m²; 100% male sex) were diagnosed with AF during the study dates. 17 (63%) were Air Force branch pilots with hypertension as the most common risk factor (26%). There were overall low CHA₂DS₂-VASc scores (mean 0.29 ± 0.47). 22 (82%) pilots were equally treated with medical rate and rhythm strategies (41% and 41%, respectively). 16 (59%) underwent pulmonary vein isolation (PVI) with zero complications. 11 (41%) pilots received warfarin and 5 (19%) received a direct oral anticoagulant for stroke prevention. After diagnosis, 12 (44%) pilots deployed and 25 (93%) were retained in military. PVI was not associated with a change in subsequent deployments rates (PVI, 38% vs no PVI, 55%; p = 0.3809) or retention rates (PVI, 94% vs no PVI, 91%; p = 0.7835).

Conclusions

United States military pilots diagnosed with AF are younger patients with few traditional AF risk factors and  they receive medical rate and rhythm strategies equally. Many pilots maintain deployment eligibility and most remain on AD status after diagnosis. PVI is not associated with differences in retention or deployment rates. Further prospective study is needed to further evaluate these findings. 

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.

The Acute Effects of an Ultramarathon on Atrial Function and Supraventricular Arrhythmias in Master Athletes

BACKGROUND

Endurance sports practice has significantly increased over the last decades, with a growing proportion of master athletes. However, concerns exist regarding the potential proarrhythmic effects induced by ultra-endurance sports. This study aimed to analyse the acute effects of an ultramarathon race on atrial remodelling and supraventricular arrhythmias in a population of master athletes.

METHODS

Master athletes participating in an ultramarathon (50 km, 600 m of elevation gain) with no history of heart disease were recruited. A single-lead ECG was recorded continuously from the day before to the end of the race. Echocardiography and 12-lead resting ECG were performed before and immediately at the end of the race.

RESULTS

The study sample consisted of 68 healthy non-professional master athletes. Compared with baseline, P wave voltage was higher after the race (p < 0.0001), and more athletes developed ECG criteria for right atrial enlargement (p < 0.0001). Most of the athletes (97%) had ≥1 premature atrial beats (PAB) during the 24-h monitoring, also organised in triplets (17%) and non-sustained supraventricular tachycardias (NSSVTs) (19%). In contrast, exercise-induced PABs, triplets, and NSSVTs were rare. One athlete developed acute atrial fibrillation during the race. After the race, no significant differences were found in biatrial dimensions. Biatrial function, estimated by peak atrial longitudinal and contraction strains, were normal both before and after the race.

CONCLUSIONS

In master athletes running an ultramarathon, acute exercise-induced atrial dysfunction was not detected, and exercise-induced supraventricular arrhythmias were uncommon. These results did not confirm the hypothesis of an acute atrial dysfunction induced by ultra-endurance exercise.

Detection of myocardial fibrosis by speckle-tracking echocardiography: from prediction to clinical applications

Myocardial fibrosis (MF) represents the underlying pathologic condition of many cardiac disease, leading to cardiac dysfunction and heart failure (HF). Biopsy studies have shown the presence of MF in patients with decompensating HF despite apparently normal cardiac function. In fact, basic indices of left ventricular (LV) function, such as LV ejection fraction (EF), fail to recognize subtle LV dysfunction caused by MF. Cardiac magnetic resonance (CMR) with late gadolinium enhancement (LGE) is currently recognized as the gold standard imaging investigation for the detection of focal and diffuse cardiac chambers MF; however, its use is limited by its availability and the use of contrast agents, while echocardiography remains the first level cardiac imaging technique due to its low cost, portability and high accessibility. Advanced echocardiographic techniques, above all speckle-tracking echocardiography (STE), have demonstrated reliability for early detection of structural myocardial abnormalities and for the prediction of prognosis in acute and chronic HF. Myocardial strain of both ventricles and also left atrium has been shown to correlate with the degree of MF, providing useful prognostic information in several diseases, such as HF, cardiomyopathies and valvular heart disease. This paper aims to provide an overview of the pathophysiology of MF and the clinical application of STE for the prediction of left and right heart chambers MF in HF patients.

Athlete’s Heart in Elite Biathlon, Nordic Cross—Country and Ski-Mountaineering Athletes: Cardiac Adaptions Determined Using Echocardiographic Data

Twelve world elite Biathlon (Bia), ten Nordic Cross Country (NCC) and ten ski-mountaineering (Ski-Mo) athletes were evaluated for pronounced echocardiographic physiological cardiac remodeling as a primary aim of our descriptive preliminary report. In this context, sports-related cardiac remodeling was analyzed by performing two-dimensional echocardiography including speckle tracking analysis as left ventricular global longitudinal strain (LV-GLS). A multicenter retrospective analysis of echocardiographic data was performed in 32 elite world winter sports athletes, which were obtained between 2020 and 2021 during the annual medical examination. The matched data of the elite world winter sports athletes (14 women, 18 male athletes, age: 18–35 years) were compared for different echocardiographic parameters. Significant differences could be revealed for left ventricular systolic function (LV-EF, p = 0.0001), left ventricular mass index (LV Mass index, p = 0.0078), left atrial remodeling by left atrial volume index (LAVI, p = 0.0052), and LV-GLS (p = 0.0003) between the three professional winter sports disciplines. This report provides new evidence that resting measures of cardiac structure and function in elite winter sport professionals can identify sport specific remodeling of the left heart, against the background of training schedule and training frequency.

Subclinical Atrial Fibrillation: A Silent Threat with Uncertain Implications

Atrial fibrillation (AF) is one of the most common cardiac arrhythmias. Implantable and wearable cardiac devices have enabled the detection of asymptomatic AF episodes-termed subclinical AF (SCAF). SCAF, the prevalence of which is likely significantly underestimated, is associated with increased cardiovascular and all-cause mortality and a significant stroke risk. Recent advances in machine learning, namely artificial intelligence-enabled ECG (AI-ECG), have enabled identification of patients at higher likelihood of SCAF. Leveraging the capabilities of AI-ECG algorithms to drive screening protocols could eventually allow for earlier detection and treatment and help reduce the burden associated with AF. Expected final online publication date for the Annual Review of Medicine, Volume 73 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Inherited and Acquired Rhythm Disturbances in Sick Sinus Syndrome, Brugada Syndrome, and Atrial Fibrillation: Lessons from Preclinical Modeling

Rhythm disturbances are life-threatening cardiovascular diseases, accounting for many deaths annually worldwide. Abnormal electrical activity might arise in a structurally normal heart in response to specific triggers or as a consequence of cardiac tissue alterations, in both cases with catastrophic consequences on heart global functioning. Preclinical modeling by recapitulating human pathophysiology of rhythm disturbances is fundamental to increase the comprehension of these diseases and propose effective strategies for their prevention, diagnosis, and clinical management. In silico, in vivo, and in vitro models found variable application to dissect many congenital and acquired rhythm disturbances. In the copious list of rhythm disturbances, diseases of the conduction system, as sick sinus syndrome, Brugada syndrome, and atrial fibrillation, have found extensive preclinical modeling. In addition, the electrical remodeling as a result of other cardiovascular diseases has also been investigated in models of hypertrophic cardiomyopathy, cardiac fibrosis, as well as arrhythmias induced by other non-cardiac pathologies, stress, and drug cardiotoxicity. This review aims to offer a critical overview on the effective ability of in silico bioinformatic tools, in vivo animal studies, in vitro models to provide insights on human heart rhythm pathophysiology in case of sick sinus syndrome, Brugada syndrome, and atrial fibrillation and advance their safe and successful translation into the cardiology arena.

Exercise characteristics and incidence of abnormal electrocardiogram response in long-distance runners with exercise-induced hypertension

While long‐distance running has important health benefits, chronic elevation of blood pressure during exercise might induce cardiac events and sudden death. This study aimed to investigate characteristics of exercise and incidence of abnormal exercise electrocardiography findings in long‐distance runners with exercise‐induced hypertension. Long‐distance runners (n = 606) underwent a questionnaire survey, history taking, and exercise stress testing, and they were classified into the non‐exercise‐induced (n = 268) and exercise‐induced (n = 338) hypertension groups. Exercise‐induced hypertension was defined as systolic blood pressure ≥210 mm Hg during maximal exercise. Abnormal electrocardiogram response (AER) were defined as abnormal electrocardiography findings, such as arrhythmias or ST‐segment changes, during exercise stress testing. There were no differences in general and exercise‐related characteristics between the non‐exercise‐induced and exercise‐induced hypertension groups. The AER group (AERg, n = 37) had a significantly longer training history and total exercise time than the non‐AER group (non‐AERg, n = 569) (p < .05). Atrial arrhythmias and ST‐segment depression were more prevalent in the exercise‐induced hypertension group than in the non‐exercise‐induced hypertension group (atrial arrhythmias: 5% [17/338] vs. 1.9% [5/268]; ST‐segment depression: 2.7% [9/338] vs. .4% [1/268]; p < .05). The incidence of AER was significantly higher in the exercise‐induced hypertension group (n = 30, 8.8%) than in the non‐exercise‐induced hypertension group (n = 7, 2.6%) (p < .05). This study showed that long‐distance runners with AER had a longer training history and total exercise time than those without AER, and the exercise‐induced hypertension group had a higher rate of AER.

Risk of atrial fibrillation in athletes: a systematic review and meta-analysis

OBJECTIVE

A systematic review, meta-analysis and meta-regression were performed on selected studies to investigate the incidence of atrial fibrillation (AF) among athletes compared with non-athlete controls.

DESIGN

Meta-analysis with heterogeneity analysis and subsequent meta-regression to model covariates were performed. The mode of exercise (endurance and mixed sports) and age were the a priori determined covariates.

DATA SOURCES

PubMed, MEDLINE, Science Direct, SPORTDiscus and the Cochrane library were searched.

ELIGIBILITY CRITERIA

Research articles published after 1990 and before 2 December 2020 were included if they reported the number of AF cases in athletes with non-athlete (physically active or inactive) control groups, were case-control or cohort studies and if data allowed calculation of OR.

RESULTS

The risk of developing AF was significantly higher in athletes than in non-athlete controls (OR: 2.46; 95% CI 1.73 to 3.51; p<0.001, Z=4.97). Mode of exercise and risk of AF were moderately correlated (B=0.1259, p=0.0193), with mixed sport conferring a greater risk of AF than endurance sport (B=-0.5476, p=0.0204). Younger (<55 years) athletes were significantly more likely to develop AF compared with older (≥55 years) athletes (B=-0.02293, p<0.001).

CONCLUSION

Athletes have a significantly greater likelihood of developing AF compared with non-athlete controls, with those participating in mixed sport and younger athletes at the greatest risk. Future studies of AF prevalence in athletes according to specific exercise dose parameters, including training and competition history, may aid further in delineating those at risk.

Characteristics of US military personnel with atrial fibrillation and associated deployment and retention rates

INTRODUCTION

Atrial fibrillation (AF) is an arrhythmia impacting military occupational performances. Despite being a recognised disqualifying condition, there is no literature describing US military service members with AF. This study aims to describe members with AF diagnoses, the distribution of treatment strategies and associated deployment and retention rates.

METHODS

Active duty service members identified with AF from 2004 to 2019 were investigated. Cardiovascular profiles, AF management strategies and military dispositions were assessed by electronic medical record review.

RESULTS

386 service members (mean age 35.0±9.4 years; 94% paroxysmal AF) with AF diagnoses were identified. 91 (24%) had hypertension followed by 75 (19%) with sleep apnoea. Mean CHA₂DS₂-VASc scores were low (0.39±0.65). Rhythm treatments were used in 173 (45%) followed by rate control strategies in 155 (40%). 161 (42%) underwent pulmonary vein isolation (PVI). In subgroup analysis of 365 personnel, 147 (40%) deployed and 248 (68%) remained active duty after AF diagnosis. Deployment and retention rates did not differ between those who received no medical therapy, rate control or rhythm strategies (p=0.9039 and p=0.6192, respectively). PVI did not significantly impact deployment or retention rates (p=0.3903 and p=0.0929, respectively).

CONCLUSION

Service members with AF are young with few AF risk factors. Rate and rhythm medical therapies were used evenly. Over two-thirds met retention standards and 40% deployed after diagnosis. There were no differences in deployment or retention between groups who receive rate therapy, rhythm medical therapy or PVI. Prospective evaluation of the efficacy of specific AF therapies on AF burden and symptomatology in service members is needed.

High-intensity endurance training is associated with left atrial fibrosis

INTRODUCTION

Endurance athletes are at higher risk for developing atrial fibrillation as compared to the general population. The exact mechanism to explain this observation is incompletely understood. Our study aimed to determine whether degree of left atrial fibrosis detected by late gadolinium-enhancement magnetic resonance imaging (LGE-MRI) differed between Masters athletes and non-athlete controls.

METHODS

We recruited 20 endurance healthy Masters athletes and 20 healthy control subjects who underwent cardiac MRI. Healthy controls were recruited during screening colonoscopies and Masters athletes were recruited through word of mouth and at competitions. The two groups were age and gender matched. None of the participants were known to have an arrhythmia. Fibrosis, as measured by late gadolinium-enhancement, was measured in each participant by blinded readers. The degree of left atrial fibrosis was compared between the two groups. All participants were recruited from the Salt Lake City region and scanned at the University of Utah healthcare complex.

RESULTS

Left ventricular function was normal in all study participants. Left atrial volumes were significantly larger in the athletes (74.2 ml ± 14.4) as compared to the healthy control subjects (60.8 mL ± 21.4) (P = .02). Mean left atrial fibrosis score, reported as a percentage of the LA, was 15.5% ± 5.9 in the athlete cohort compared to 9.6% ± 4.9 in the controls (P = .002).

CONCLUSIONS

To our knowledge this is the first study that describes, characterizes and specifically quantifies fibrotic changes within the left atrium of highly trained endurance athletes. Increased atrial fibrosis seen in this population may be an early indicator for endurance athletes at risk of developing atrial arrhythmias.

Efficacy of Physical Exercise on the Quality of Life, Exercise Ability, and Cardiopulmonary Fitness of Patients With Atrial Fibrillation: A Systematic Review and Meta-Analysis

Objective: Physical exercise is recommended to help prevent lifestyle diseases. The present study was designed to quantify the efficacy of physical exercise on the quality of life (QoL), exercise ability and cardiopulmonary fitness of patients with atrial fibrillation (AF).

Method: A comprehensive systematic literature search was performed in Medline, Embase, Cochrane Library, Web of Science and PubMed databases (from 1970 to December 1st, 2019) for randomized controlled trials (RCTs) comparing physical exercise combined with AF routine treatments to routine treatments alone. The meta-analysis was conducted following PRISMA guidelines. Our main outcomes were QoL (measured by the Short-Form 36 scale, SF-36), exercise ability (measured by the 6-min walk test, 6MWT) and cardiopulmonary fitness (measured by peak oxygen uptake and resting heart rate). Quality assessments were conducted using the Cochrane Collaboration tool.

Results: Twelve trials involving 819 patients met the criteria for analysis. The results showed that physical exercise improved the QoL by enhancing physical functioning [standardized mean difference (SMD) = 0.63, 95%CI: 0.18–1.09; p = 0.006], general health perceptions (SMD = 0.64, 95%CI: 0.35–0.93; p < 0.001) and vitality (SMD = 0.51, 95%CI: 0.31–0.71; p < 0.001); increased exercise ability by improving the 6MWT performance (SMD = 0.69, 95%CI: 0.19–1.119; p = 0.007); and enhanced peak VO₂ (SMD = 0.37, 95%CI: 0.16–0.57; p < 0.001) while reducing resting heart rate (SMD = −0.39, 95%CI: −0.65 to −0.13; p = 0.004). In addition, meta-regression analysis showed that training mode (p_{physicalfunctioning} = 0.012, p_{generalhealthperceptions} = 0.035) and training duration (p = 0.047) were the main factors of an intervention that influenced the effect size. Following sub-group analysis, we found that aerobics, Yoga and longer training durations (≥60 min) showed larger improvements.

Conclusion: In summary, our meta-analysis shows that physical exercise has a positive effect on the QoL, exercise ability and cardiopulmonary fitness in AF patients. When physicians offer exercise recommendations to AF patients, they should consider both the training mode and training duration to achieve maximum results.

Epidemiology of Atrial Fibrillation in the 21st Century: Novel Methods and New Insights

Accompanying the aging of populations worldwide, and increased survival with chronic diseases, the incidence and prevalence of atrial fibrillation (AF) are rising, justifying the term global epidemic. This multifactorial arrhythmia is intertwined with common concomitant cardiovascular diseases, which share classical cardiovascular risk factors. Targeted prevention programs are largely missing. Prevention needs to start at an early age with primordial interventions at the population level. The public health dimension of AF motivates research in modifiable AF risk factors and improved precision in AF prediction and management. In this review, we summarize current knowledge in an attempt to untangle these multifaceted associations from an epidemiological perspective. We discuss disease trends, preventive opportunities offered by underlying risk factors and concomitant disorders, current developments in diagnosis and risk prediction, and prognostic implications of AF and its complications. Finally, we review current technological (eg, eHealth) and methodological (artificial intelligence) advances and their relevance for future prevention and disease management.

Independent effect of physical activity and resting heart rate on the incidence of atrial fibrillation in the general population

While physical activity (PA) may influence resting heart rate (RHR), and a low RHR may be a risk factor for atrial fibrillation (AF), controversy exists regarding the association between PA and development of AF. Using data from a Korean, prospective population cohort, we investigated the independent effect of PA and RHR on the incidence of AF in the general population. A total of 8,811 participants aged 40-69 years were analyzed. Total PA assessed based on questionnaires was divided into quartiles, with the lowest to the highest being Q1, Q2, Q3, and Q4. During a median follow-up of 139 months, AF developed in 167 participants (1.9%). Q3 of total PA was associated with a significantly lower risk of AF than Q1 even after adjusting for RHR as a covariate, but Q4 was not. The risk of AF was higher in participants with RHR < 60 bpm than in those with RHR 70-85 bpm, and the significance persisted after adjusting for PA as a covariate. This study showed that a moderate amount of total PA was associated with a lower risk of incident AF independent of RHR and that low RHR was an independent risk factor for AF in the general Korean population.

Anti-arrhythmic therapy in athletes

The spectrum of arrhythmias that may be encountered in athletes ranges from isolated ectopic beats to ventricular tachycardia, usually in the context of a structurally normal heart. Anti-arrhythmic therapy in these individuals may be particularly challenging because of the young age, the hypervagotonic state, the desire to maintain a high physical performance, the reluctance to take medications and the need to avoid molecules included in the list of prohibited drugs of the World Anti-Doping Agency. Furthermore, the possible serious adverse effects of anti-arrhythmic drugs should be balanced against the benign nature of arrhythmias in patients with no underlying heart disease. The review summarizes the most common arrhythmias of athletes and the possible therapeutic options, including anti-arrhythmic drugs and non-pharmacological interventions. Eligibility criteria according to current guidelines are also addressed.

Association of sex, age and education level with patient reported outcomes in atrial fibrillation

BACKGROUND

In atrial fibrillation (AF), there are known sex and sociodemographic disparities in clinical outcomes such as stroke. We investigate whether disparities also exist with respect to patient-reported outcomes. We explored the association of sex, age, and education level with patient-reported outcomes (AF-related quality of life, symptom severity, and emotional and functional status).

METHODS

The PaTH AF cohort study recruited participants (N = 953) with an AF diagnosis and age ≥ 18 years across 4 academic medical centers. We performed longitudinal multiple regression with random effects to determine if individual characteristics were associated with patient-reported outcomes.

RESULTS

Women reported poorer functional status (β - 2.23, 95% CI: -3.52, - 0.94) and AF-related quality of life (β - 4.12, 95% CI: -8.10, - 0.14), and higher symptoms of anxiety (β 2.08, 95% CI: 0.76, 3.40), depression (β 1.44, 95% CI: 0.25, 2.63), and AF (β 0.29, 95% CI: 0.08, 0.50). Individuals < 60 years were significantly (p < 0.05) more likely to report higher symptoms of depression, anxiety, and AF, and poorer AF-related quality of life. Lack of college education was associated with reporting higher symptoms of AF (β 0.42, 95% CI: 0.17, 0.68), anxiety (β 1.86, 95% CI: 0.26, 3.45), and depression (β 1.11, 95% CI: 0.15, 2.38), and lower AF-related quality of life (β - 4.41, 95% CI: -8.25, - 0.57) and functional status.

CONCLUSION

Women, younger adults, and individuals with lower levels of education reported comparatively poor patient-reported outcomes. These findings highlight the importance of understanding why individuals experience AF differently based on certain characteristics.

Mid-term development of the right ventricle in competitive athletes

BACKGROUND

Long-term intensive training induces physiological, morphological, and functional adaption of the athlete's heart.

PURPOSE

To evaluate the development of athlete's heart during a mid-term follow-up of competitive athletes using cardiac magnetic resonance (CMR).

MATERIAL AND METHODS

Eighteen competitive long-distance runners and triathletes (age 43 ± 13 years, 3 women) were prospectively examined in a longitudinal follow-up study 5.05 ± 0.6 years after baseline. CMR at 1.5-T was performed for functional and late gadolinium enhancement (LGE) imaging. Left ventricular (LV) and right ventricular (RV) end-diastolic volume (LVEDV, RVEDV) as well as ejection fraction (LVEF, RVEF), LV myocardial mass (LVMM), and atrial sizes were determined and compared to baseline in matched pairs statistics for paired difference.

RESULTS

LVEDV (197 ± 38 mL vs. 196 ± 38 mL, paired difference -0.9 mL, P = 0.7) and LVEF (62 ± 7% vs. 62 ± 5%, paired difference 0.1%, P = 0.9) did not change during the follow-up period, whereas LVMM increased significantly (149 ± 31 g vs.164 ± 32 g, paired difference 14 g, P < 0.0001). RVEDV significantly increased from 221 ± 47 mL at baseline to 230 ± 52 mL (paired difference 10 mL, P = 0.0033). RVEF decreased from baseline 57 ± 8% to 53 ± 7% (paired difference -3%, P = 0.0234). Left atrial size showed no significant changes (24 ± 5 cm² vs. 25 ± 6 cm², paired difference 0.5 cm², P = 0.17) and right atrial size increased significantly (30 ± 5 cm² vs. 32 ± 4 cm², paired difference 2 cm², P = 0.0054).

CONCLUSION

This study supports the theory of ongoing remodeling in an athlete's heart. Predominantly the right heart can further enlarge in a mid-term period. This response seems not linearly dependent on a steady, decreased, or increased training volume.

An Update on the Role of Cardiorespiratory Fitness, Structured Exercise and Lifestyle Physical Activity in Preventing Cardiovascular Disease and Health Risk

The cardiovascular disease (CVD) pandemic has placed considerable strain on healthcare systems, quality of life, and physical function, while remaining the leading cause of death globally. Decades of scientific investigations have fortified the protective effects of cardiorespiratory fitness (CRF), exercise training, and physical activity (PA) against the development of CVD. This review will summarize recent efforts that have made significant strides in; 1) the application of novel analytic techniques to increase the predictive utility of CRF; 2) understanding the protective effects of long-term compliance to PA recommendations through large cohort studies with multiple points of assessment; 3) and understanding the potential harms associated with extreme volumes of PA.

Burden of ventricular arrhythmias at 12-lead 24-hour ambulatory ECG monitoring in middle-aged endurance athletes versus sedentary controls

Background

Whether prolonged and intense exercise increases the incidence of ventricular arrhythmias in middle-aged athletes remains to be established.

Design

Prospective, case-control.

Methods

We studied 134 healthy competitive athletes >30 years old (median age 45 (39–51) years, 83% males) who had been engaged in 9 ± 2 h per week of endurance sports activity (running, cycling, triathlon) for 13 ± 4 consecutive years. One hundred and thirty-four age- and gender-matched individuals served as controls. Both groups underwent 12-lead 24-h ambulatory electrocardiogram monitoring, which included a training session in athletes. Ventricular arrhythmias were evaluated in terms of number, complexity (i.e. couplet, triplet or non-sustained ventricular tachycardia), exercise-inducibility and morphology.

Results

Thirty-five (26%) athletes and 31 (23%) controls showed >10 isolated premature ventricular beats or ≥1 complex ventricular arrhythmia ( p = 0.53). Athletes with ventricular arrhythmias were older (median 48 versus 43 years old, p = 0.03) but did not differ with regard to hours of training and years of activity compared with athletes without ventricular arrhythmias. Ten (7%) athletes and six (5%) controls showed >500 premature ventricular beats/24 h ( p = 0.30): the most common ventricular arrhythmia morphologies were infundibular (six athletes and five controls) and fascicular (two athletes and one control).

Conclusions

The prevalence of ventricular arrhythmias at 24-hour ambulatory electrocardiogram monitoring did not differ between middle-aged athletes and sedentary controls and was unrelated to the amount and duration of exercise. These findings do not support the hypothesis that endurance sports activity increases the burden of ventricular arrhythmias. Among individuals with frequent premature ventricular beats, the predominant ectopic QRS morphologies were consistent with the idiopathic and benign nature of the arrhythmia.

Age as a Critical Determinant of Atrial Fibrillation: A Two-sided Relationship

The incidence of atrial fibrillation (AF), the most common sustained arrhythmia and a major public health burden, increases exponentially with age. However, mechanisms underlying this long-recognized association remain incompletely understood. Experimental and human studies have demonstrated the involvement of aging in several arrhythmogenic processes, including atrial electrical and structural remodelling, disturbed calcium homeostasis, and enhanced atrial ectopic activity/increased vulnerability to re-entry induction. Given this wide range of putative mechanisms, the task of delineating the specific effects of aging responsible for AF promotion is not simple, as aging is itself associated with increasing prevalence of a host of AF-predisposing conditions, including heart failure, coronary artery disease, and hypertension. Although we usually think of old age promoting AF, there is also evidence that young age may actually have a protective effect against AF occurrence. For example, the low AF incidence among populations of young patients with significant structural congenital heart disease and substantial atrial enlargement/remodelling suggests that younger age might protect against fibrillation in the diseased atrium; efforts at understating how younger age may prevent AF might be helpful in elucidating missing mechanistic links between AF and age. The goal of this paper is to review the epidemiologic and pathophysiologic evidence regarding mechanisms underlying age-related AF. Although the therapeutic options for AF have recently improved, major gaps still remain and a better understanding of the special relationship between age and AF may be important for the identification of new targets for therapeutic innovation.

[Sports in Patients with Heart Disease: What Should Be Recommended?]

Sports in Patients with Heart Disease: What Should Be Recommended? Abstract. Sports is recommended in the European guidelines for the prevention and initial treatment of many cardiovascular diseases as well as the metabolic syndrome. However, the individually recommended intensity and duration of physical activity that unfolds the maximal protective effects in terms of prevention, largely differs. Indeed, a J-curve relationship with regard to exercise training has been postulated, with the assumption that too much sports is equally harmful or potentially even more harmful than too little sports. In this review, we try to answer the question of how much and which sports is optimal for cardiac patients.

Cardiovascular exercise and burden of arrhythmia in patients with atrial fibrillation - A randomized controlled trial

Background

Physical activity at moderate-high intensity is recommended to prevent lifestyle diseases. Patients with atrial fibrillation are at risk of a sedentary lifestyle due to fear of exercise-induced episodes of atrial fibrillation. The burden of arrhythmia can be reduced by physical exercise. The effect of exercise intensity on burden of atrial fibrillation needs to be studied further.

Methods and results

In a 12-week randomized controlled trial, 76 patients with paroxysmal/persistent atrial fibrillation were allocated to perform exercise at either low intensity or high intensity (50% and 80% of maximal perceived exertion, respectively). Primary outcome was burden of AF measured by daily electrocardiography-reporting during 12 weeks. Secondarily, change in maximal oxygen uptake (peak VO₂) and 1-year hospitalization was compared between low and high intensity exercise. Sixty-three patients completed the follow-up. In the intention-to-treat analysis, we found no statistical difference in burden of atrial fibrillation between low and high intensity exercise (incidence rate ratio 0.742, 95% CI 0.29–1.91, P = 0.538). No serious adverse events were reported and there was no difference in hospitalization between the two exercise groups. Both exercise groups improved significantly in peak VO₂ (low intensity: 3.62 mL O₂/kg/min, SD 3.77; high intensity: 2.87 mL O₂/kg/min, SD 4.98), with no statistical difference between-groups (mean difference: 0.76 mL O₂/kg/min, 95% CI -3.22–1.7).

Conclusions

High intensity physical exercise was not superior to low intensity physical exercise in reducing burden of atrial fibrillation. HI exercise was well tolerated; no evidence of an increased risk was found for HI compared to LI exercise. Larger studies are required to further prove our findings.

Trial registration

ClinicalTrials.gov NCT01817998

Excessive Exercise Habits in Marathoners as Novel Indicators of Masked Hypertension

Background. Excessive exercise such as marathon running increases the risk of cardiovascular events that may be related to myocardial infarction and sudden death. We aimed to investigate that the exercise characteristics can be used as a novel indicator of masked hypertension. Methods. A total of 571 middle-aged recreational male marathoners were assigned to a high blood pressure group (HBPG; n = 214) or a normal blood pressure group (NBPG; n = 357). A graded exercise test was used to examine the hemodynamic response and cardiac events, and the personal exercise characteristics were recorded. Results. Systolic blood pressure and diastolic blood pressure were higher in the HBPG than in the NBPG (p < 0.05, all). The marathon history, exercise intensity, and time were longer and higher, whereas the marathon completion duration was shorter in the HBPG than in NBPG (p < 0.05, all). HBPG showed a higher frequency of alcohol consumption than NBPG (p < 0.05). Conclusion. More excessive exercise characteristics than the normative individuals. If the individuals exhibit high blood pressure during rest as well as exercise, the exercise characteristics could be used as a novel indicator for masked hypertension.

Long-Term, Competitive Swimming and the Association with Atrial Fibrillation

Background

Endurance exercise plays a role in cardiovascular risk reduction, but may also be a risk factor for atrial fibrillation. This study was performed to assess the prevalence of atrial fibrillation in a population of long-term, competitive swimmers compared with patients within an internal medicine clinic with known risk factors for atrial fibrillation such as diabetes mellitus and hypertension.

Methods

This cross-sectional study utilized survey data comparing the prevalence of atrial fibrillation in swimmers to a general internal medicine population. A multi-national group of swimmers over the age of 60 were surveyed, and a chart review was performed on a random sample of age-matched internal medicine patients. The primary outcome was the diagnosis of atrial fibrillation. Univariate analysis was used for means of proportions of the responses, and a multivariate logistic regression analysis was performed with diagnosis of atrial fibrillation as the dependent variable.

Results

Forty-nine swimmers completed surveys and 100 age-matched internal medicine patients underwent chart review. Swimmers reported atrial fibrillation in 13 cases (26.5 %) compared to 7 (7 %) in the comparison group (p = 0.001). A diagnosis of hypertension or diabetes mellitus was present in 23 (46.9 %) and 1 (2 %) of the swimmers, respectively, as compared to 72 (72 %, p = 0.003) and 32 (32 %, p < 0.001) in the comparison group. Age, presence of diabetes mellitus, and swimming history were variables included in the logistic regression, in relation to atrial fibrillation. Swimming was associated with an odds ratio of 8.739 (95 % CI 2.290 to 33.344, p = 0.015).

Conclusions

Long-term, competitive swimmers have an increased prevalence of atrial fibrillation compared to internal medicine patients, despite the higher burden of diabetes mellitus and hypertension in the internal medicine group.

Electronic supplementary material

The online version of this article (doi:10.1186/s40798-016-0066-8) contains supplementary material, which is available to authorized users.