Arrhythmias and Adaptations of the Cardiac Conduction System in Former National Football League Players

Racial and Gender Differences in Cardiorespiratory Fitness and Atrial Fibrillation

The expanding field of cardiorespiratory fitness (CRF) in individuals with and without atrial fibrillation (AF) presents a complex landscape, demanding careful interpretation of the existing research. AF, characterized by significant mortality and morbidity, prompts the exploration of strategies to mitigate its impact. Increasing physical activity (PA) levels emerges as a promising avenue to address AF risk factors, such as obesity, hypertension, and diabetes mellitus, through mechanisms of reduced vasoconstriction, endothelin-1 modulation, and improved insulin sensitivity. However, caution is warranted, as recent investigations suggest a heightened incidence of AF, particularly in athletes engaged in high-intensity exercise, due to the formation of ectopic foci and changes in cardiac anatomy. Accordingly, patients should adhere to guideline-recommended amounts of low-to-moderate PA to balance benefits and minimize adverse effects. When looking closer at the current evidence, gender-specific differences have been observed and challenged conventional understanding, with women demonstrating decreased AF risk even at extreme exercise levels. This phenomenon may be rooted in divergent hemodynamic and structural responses to exercise between men and women. Existing research is predominantly observational and limited to racially homogenous populations, which underscores the need for comprehensive studies encompassing diverse, non-White ethnic groups in athlete and non-athlete populations. These individuals exhibit a disproportionately high burden of AF risk factors that could be addressed through improved CRF. Despite the limitations, randomized control trials offer promising evidence for the efficacy of CRF interventions in patients with preexisting AF, showcasing improvements in clinically significant AF outcomes and patient quality of life. The potential of CRF as a countermeasure to the consequences of AF remains an area of great promise, urging future research to delve deeper to explore its role within specific racial and gender contexts. This comprehensive understanding will contribute to the development of tailored strategies for optimizing cardiovascular health and AF prevention in all those who are affected.

Effects of different exercise methods and intensities on the incidence and prognosis of atrial fibrillation

Atrial fibrillation (AF), the most common sustained arrhythmia in clinical practice, exhibits a higher risk of cardiovascular adverse events. Exercise plays a crucial role in AF prevention, but the effects of different exercise types and doses are inconclusive. This review aims to comprehensively explore the most recent evidence and possible mechanisms of diverse exercise modalities concerning AF incidence and therapeutic outcomes. Multiple studies underscore the efficacy of moderate-intensity continuous training (MICT) in reducing AF incidence and symptom burden, rendering it the currently favored exercise therapy for AF patients. High-intensity interval training (HIIT) shows promise, potentially surpassing MICT, especially in reducing age-related AF susceptibility and improving symptoms and exercise capacity. Conversely, prolonged high-intensity endurance exercise exacerbates AF risk due to excessive exercise volume, with potential mechanisms encompassing irreversible atrial remodeling, heightened inflammation, and increased vagal tone. In summation, MICT is a secure strategy for populations in mitigating the risk associated with AF incidence and secondary cardiovascular events and should be encouraged. Also, it is recommended to initiate large-scale clinical intervention trials encompassing a variety of exercise types to delineate the optimal exercise prescription for cardiovascular patients, including those afflicted with AF.

Atrial Fibrillation in Endurance Training Athletes: Scoping Review

Background

Moderate regular physical activity is indicated to avoid atrial fibrillation (AF), whereas athletes should be counseled that long-lasting vigorous sports engagement may cause AF, according to the 2016 European Society of Cardiology (ESC) recommendations for AF treatment. Exercise and AF are complex.

Objectives

To evaluate the relationship between Endurance training and AF, in addition to the starting point/trigger by which Endurance Training causes impairment of cardiac function and AF, considering the time and intensity of Endurance training.

Materials and Methods

We synthesized evidence from articles published in the PubMed, EMBASE, and SciELO databases using their respective Boolean operators. A total of 112 original articles related to AF and endurance athletes published up to the year 2023 were reviewed.

Results

Our study verified multiples aspects of the genesis of AF in athletes, such as cardiac adaptations to exercise, disturbances in cardiac injury biomarkers, sex differences in cardiac adaptations and their role in AF risk, and the relationship between body composition (height, weight, and physical fitness) and AF pathogenesis.

Conclusions

Variations in cardiac structure (increased atrial thickness and size in addition to myocardial fibrosis) and significant increases in vagal tone (sinus bradycardia and imbalances in sympathetic and parasympathetic activation) shorten the refractory period shortening in athletes, induce the onset of re-entrance mechanisms, and serve as ectopic triggers that can lead to AF.

Holter-determined arrhythmias in young elite athletes with suspected risk: Insights from a 20-year experience

Purpose

We assessed the occurrence of rhythm alterations in elite athletes with suspected risk using Holter monitoring, and the association of Holter-determined rhythm alterations with echocardiographic findings.

Methods

A large cohort of Spanish elite athletes (N = 6,579, 34% female) underwent in-depth cardiological examination (including echocardiographic evaluation, and resting and exercise electrocardiogram [ECG]) between 01/02/1998 and 12/31/2018. Holter monitoring was performed in those reporting cardiovascular symptoms, with suspicion of cardiac structural abnormalities potentially associated with dangerous arrhythmias, or with resting/exercise ECG features prompting a closer examination. We assessed the occurrence of cardiac rhythm alterations, as well as the association between echocardiography-determined conditions and rhythm alterations.

Results

Most athletes (N = 5925) did not show any sign/symptom related to arrhythmia (including normal resting and exercise/post-exercise ECG results) whereas 9.9% (N = 654; 28% female; median age, 24 years [interquartile range 19–28]; competition experience [mean ± SD] 10±6 years) met the criteria to undergo Holter monitoring. Among the latter, sinus bradycardia was the most common finding (present in 96% of cases), yet with a relatively low proportion of severe (<30 bpm) bradycardia (12% of endurance athletes during night-time). Premature atrial and ventricular beats were also common (61.9 and 39.4%, respectively) but sinus pauses ≥3 s, high-grade atrioventricular blocks, and atrial fibrillation/flutter were rare (<1%). Polymorphic premature ventricular contractions (PVC, 1.4%) and idioventricular rhythm (0.005%) were also rare. PVC couplets were relatively prevalent (10.7%), but complex ventricular arrhythmias were not frequent (PVC triplets: 1.8%; sustained ventricular tachycardia: 0.0%; and nonsustained ventricular tachycardia: 1.5%). On the other hand, no associations were found between arrhythmias (including their different morphologies) and major cardiac structural alterations (including mitral prolapse). However, an association was found between mild mitral regurgitation and supraventricular (odds ratio 2.61; 95% confidence interval 1.08–6.32) and ventricular (2.80; 1.15–6.78; p = 0.02) arrhythmias, as well as between mild or moderate mitral regurgitation and ventricular arrhythmias (2.49; 1.03–6.01).

Conclusions

Irrespective of the sports discipline, “dangerous” ventricular arrhythmias are overall infrequent even among young elite athletes who require Holter monitoring due to the presence of symptoms or abnormal echocardiographic/ECG findings, and do not seem to be associated with underlying serious cardiac structural pathologies.

Association of Playing College American Football With Long-term Health Outcomes and Mortality

IMPORTANCE

Exposure to repetitive head impacts from playing American football (including impacts resulting in symptomatic concussions and subconcussive trauma) is associated with increased risk for later-life health problems, including cognitive and neuropsychiatric decline and neurodegenerative disease. Most research on long-term health consequences of playing football has focused on former professional athletes, with limited studies of former college players.

OBJECTIVES

To estimate the prevalence of self-reported health conditions among former college football players compared with a sample of men in the general population as well as standardized mortality ratios (SMRs) among former college football players.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included data from 447 former University of Notre Dame (ND) football players aged 59 to 75 years who were seniors on the rosters from 1964 to 1980. A health outcomes survey was distributed to living players and next of kin of deceased players for whom contact information was available. The survey was completed from December 2018 to May 2019.

EXPOSURE

Participation in football at ND.

MAIN OUTCOMES AND MEASURES

Prevalence of health outcomes was compared between living former players who completed the survey and propensity score-matched participants in the Health and Retirement Study (HRS). Standardized mortality ratios of all causes and specific causes of death among all former players were compared with those among men in the general US population.

RESULTS

A total of 216 living players completed the health survey (median age, 67 years; IQR, 63-70 years) and were compared with 638 participants in the HRS (median age, 66 years; IQR, 63-70 years). Former players reported a higher prevalence of cognitive impairment (10 [5%] vs 8 [1%]; P = .02), headaches (22 [10%] vs 22 [4%]; P = .001), cardiovascular disease (70 [33%] vs 128 [20%]; P = .001), hypercholesterolemia (111 [52%] vs 182 [29%]; P = .001), and alcohol use (185 [86%] vs 489 [77%]; P = .02) and a lower prevalence of diabetes (24 [11%] vs 146 [23%]; P = .001). All-cause mortality (SMR, 0.54; 95% CI, 0.42-0.67) and mortality from heart (SMR, 0.64; 95% CI, 0.39-0.99), circulatory (SMR, 0.23; 95% CI, 0.03-0.83), respiratory (SMR, 0.13; 95% CI, 0.00-0.70), and digestive system (SMR, 0.13; 95% CI, 0.00-0.74) disorders; lung cancer (SMR, 0.26; 95% CI, 0.05-0.77); and violence (SMR, 0.10; 95% CI, 0.00-0.58) were significantly lower in the ND cohort than in the general population. Mortality from brain and other nervous system cancers was significantly higher in the ND cohort (SMR, 3.82; 95% CI, 1.04-9.77). Whereas point estimates were greater for all neurodegenerative causes (SMR, 1.42; 95% CI, 0.29-4.18), amyotrophic lateral sclerosis (SMR, 2.93; 95% CI, 0.36-10.59), and Parkinson disease (SMR, 2.07; 95% CI, 0.05-11.55), the difference did not reach statistical significance.

CONCLUSIONS AND RELEVANCE

In this cohort study of former college football players, both positive and negative health outcomes were observed. With more than 800 000 former college players living in the US, additional research appears to be needed to provide stakeholders with guidance to maximize factors that improve health outcomes and minimize factors that may increase risk for later-life morbidity and mortality.

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.

Wearable Technology and Analytics as a Complementary Toolkit to Optimize Workload and to Reduce Injury Burden

Wearable sensors enable the real-time and non-invasive monitoring of biomechanical, physiological, or biochemical parameters pertinent to the performance of athletes. Sports medicine researchers compile datasets involving a multitude of parameters that can often be time consuming to analyze in order to create value in an expeditious and accurate manner. Machine learning and artificial intelligence models may aid in the clinical decision-making process for sports scientists, team physicians, and athletic trainers in translating the data acquired from wearable sensors to accurately and efficiently make decisions regarding the health, safety, and performance of athletes. This narrative review discusses the application of commercial sensors utilized by sports teams today and the emergence of descriptive analytics to monitor the internal and external workload, hydration status, sleep, cardiovascular health, and return-to-sport status of athletes. This review is written for those who are interested in the application of wearable sensor data and data science to enhance performance and reduce injury burden in athletes of all ages.

Lacosamide-associated second-degree atrioventricular block in a healthy, young athlete

Lacosamide enhances slow inactivation of voltage-gated sodium channels and can lead to dose-dependent PR interval prolongation. Previously, lacosamide has been associated with second-degree atrioventricular (AV) heart block in the context of multiple medical comorbidities and/or in the elderly with multimorbidity on other dromotropic agents. We report a case of second-degree AV block occurring in a healthy, athletic young adult. The patient had baseline bradycardia with no known cardiac comorbidities. He was exquisitely sensitive to lacosamide with EKG and telemetry changes developing on the order of hours after receiving intravenous lacosamide. Lacosamide was subsequently stopped, the second-degree AV block was no longer present and EKG returned to baseline. We hypothesize that his sensitivity to lacosamide-induced AV block was possibly secondary to his baseline bradycardia with early repolarization changes. The case underscores the importance of surveillance cardiac monitoring. While medical comorbidities and an older age may portend a greater risk of PR prolongation, routine EKGs should be considered in all patients receiving lacosamide.

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This is a case of second-degree AV block with lacosamide in a healthy, young adult.

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PR prolongation can be seen with lacosamide irrespective of medical comorbidities.

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Surveillance cardiac monitoring should be considered in patients taking lacosamide.

Monitoring the health of transitioning professional footballers: protocol of an observational prospective cohort study

INTRODUCTION

Transitioning out of professional football is a challenging time in most players' lives. During these preretirement and postretirement years, professional footballers may struggle with their mental, musculoskeletal, neurocognitive and cardiovascular health. Currently, longitudinal data about these health conditions are lacking. This article presents the design of a prospective cohort study with the primary aim of gathering epidemiological evidence about the onset and course of mental, musculoskeletal, neurocognitive and cardiovascular health conditions in professional footballers during their preretirement and postretirement years and evaluating the associations between risk indicators and the health conditions under study in these players.

METHODS AND ANALYSIS

An observational prospective cohort study with repeated measurements over a follow-up period of 10 years will be conducted among at least 200 professional footballers (male; 27 (±1) years old). Mental health will be explored by assessing symptoms of distress, anxiety, depression, sleep disturbance, alcohol misuse, drug misuse and disordered eating. Musculoskeletal health will be explored by assessing severe joint injury and related surgery, clinical and radiological osteoarthritis, and joint function (hips, knees and ankles). Neurocognitive health will be explored by assessing the concussion, brain structure and functioning, and neurocognitive functioning. Cardiovascular health will be explored by assessing blood pressure, lipid profile and ECG abnormalities.

ETHICS AND DISSEMINATION

Ethical approval for the study was provided by the Medical Ethics Review Committee of the Amsterdam University Medical Centers. The results of the study will be submitted to peer-reviewed journals, will be presented at scientific conferences and will be released in the media (postpublication).

TRIAL REGISTRATION NUMBER

The Dutch Trial Registry (Drake Football Study NL7999).

Arrhythmias and Adaptations of the Cardiac Conduction System in Former National Football League Players

Background

Habitual high‐intensity endurance exercise is associated with increased atrial fibrillation (AF) risk and impaired cardiac conduction. It is unknown whether these observations extend to prior strength‐type sports exposure. The primary aim of this study was to compare AF prevalence in former National Football League (NFL) athletes to population‐based controls. The secondary aim was to characterize other conduction system parameters.

Methods and Results

This cross‐sectional study compared former NFL athletes (n=460, age 56±12 years, black 47%) with population‐based controls of similar age and racial composition from the cardiovascular cohort Dallas Heart Study‐2 (n=925, age 54±9 years, black 53%). AF was present in 28 individuals (n=23 [5%] in the NFL group; n=5 [0.5%] in the control group). After controlling for other cardiovascular risk factors in multivariable regression analysis, former NFL participation remained associated with a 5.7 (95% CI: 2.1–15.9, P<0.001) higher odds ratio of AF. Older age, higher body mass index, and nonblack race were also independently associated with higher odds ratio of AF, while hypertension and diabetes mellitus were not. AF was previously undiagnosed in 15/23 of the former NFL players. Previously undiagnosed NFL players were rate controlled and asymptomatic, but 80% had a CHA₂DS₂‐VASc score ≥1. Former NFL players also had an 8‐fold higher prevalence of paced cardiac rhythms (2.0% versus 0.25%, P<0.01), compared with controls. Furthermore, former athletes had lower resting heart rates (62±11 versus 66±11 beats per minute, P<0.001), and a higher prevalence of first‐degree atrioventricular block (18% versus 9%, P<0.001).

Conclusions

Former NFL participation was associated with an increased AF prevalence and slowed cardiac conduction when compared with a population‐based control group. Former NFL athletes who screened positive for AF were generally rate controlled and asymptomatic, but 80% should have been considered for anticoagulation based on their stroke risk.