Abstract
Recent studies have reported on an association between endurance sport, atrial enlargement and the development of lone atrial fibrillation in younger, male cohorts. The atrial morphology and function of middle‐aged, physically‐active males and females have not been well studied. We hypothesized that middle‐aged males would demonstrate larger left atrium (LA) and right atrium (RA) volumes compared to females, but atrial function would not differ. LA and RA volume and function were evaluated at rest in healthy adults, using a standardized 3.0Tesla cardiac magnetic resonance protocol. Physical activity, medical history, and maximal oxygen consumption (V˙O2peak) were also assessed. Physically‐active, middle‐aged men (n = 60; 54 ± 5 years old) and women (n = 30; 54 ± 5 years old) completed this study. Males had a higher body mass index, systolic blood pressure, and V˙O2peak than females (p < .05 for all), despite similar reported physical activity levels. Absolute and BSA and height‐indexed LA and RA maximum volumes were higher in males relative to females, despite no differences in ejection fractions (p < .05 for all). In multivariable regression, male sex p < .001) and V˙O2peak (p = .004) were predictors of LA volume (model R 2 = 0.252), whereas V˙O2peak (p < .001), male sex (p = .03), and RV EF (p < .05) were predictors of RA volume (model R 2 = 0.377). While middle‐aged males exhibited larger atrial volumes relative to females, larger, prospective studies are needed to explore the magnitude of physiologic atrial remodeling and functional adaptations in relation to phenotypic factors.
Highlights
Long-term vigorous physical activity and exercise have been associated with cardiac morphological adaptations known as the “Athlete's Heart”.1 The extent of this remodeling in the atria has been well characterized in younger male and female elite endurance athletes using echocardiography.[2,3] there is paucity of literature describing atrial structure and function in middle-aged physicallyactive adults, despite the high participation rates of recreational to sub-elite middle-aged endurance athletes.[4]
A recent echocardiography study has reported an association between larger left atrial size and higher cardiorespiratory fitness in physically-active adults across the lifespan.[7]
While cardiac magnetic resonance (CMR) has been applied to quantify atrial morphology in younger elite athletes,[9,10] only a single, small study has been completed in middle-aged males consisting of 10 former elite athletes and five controls.[11]
Summary
Long-term vigorous physical activity and exercise have been associated with cardiac morphological adaptations known as the “Athlete's Heart”.1 The extent of this remodeling in the atria has been well characterized in younger male and female elite endurance athletes using echocardiography.[2,3] there is paucity of literature describing atrial structure and function in middle-aged physicallyactive adults, despite the high participation rates of recreational to sub-elite middle-aged endurance athletes.[4]. A recent echocardiography study has reported an association between larger left atrial size and higher cardiorespiratory fitness in physically-active adults across the lifespan.[7] While echocardiography is a common first tool to evaluate cardiac structure, it underestimates cardiac volumes in comparison to the gold standard of cardiac magnetic resonance (CMR) imaging.[8] While CMR has been applied to quantify atrial morphology in younger elite athletes,[9,10] only a single, small study has been completed in middle-aged males consisting of 10 former elite athletes and five controls.[11] The extent of atrial remodeling in this cohort may be salient, as studies suggest a potential predilection for exercise induced cardiac remodeling and lone atrial fibrillation,[12] in male athletes.[13] female athletes are less likely to develop atrial fibrillation at a younger age than men, and unlike men, there is no association between longstanding exercise dose and risk of atrial fibrillation.[13]
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