Increased left atrial size is associated with reduced atrial stiffness and preserved reservoir function in athlete’s heart

Abstract

Left atrial (LA) fibrosis with increased stiffness has been assumed to be the substrates for occurrence of atrial arrhythmias in athletes. However, this hypothesis has not yet been confirmed in humans. Aim of this study was, therefore, to assess LA remodeling and stiffness in competitive athletes. 150 competitive athletes and 90 age and sex-matched sedentary subjects were analyzed by speckle-tracking echocardiography to measure peak atrial longitudinal strain (PALS) and peak atrial contraction strain (PACS). LA stiffness was determined using E/e' ratio in conjunction with PALS. Left ventricular (LV) stiffness was also calculated. LA volume index was greater in athletes as compared with controls (24.6 ± 7.3 vs. 18.4 ± 7.8 mL/m(2), p < .0001). LA PALS, LA PACS, and E/e' ratio were lower in athletes in comparison with controls (p < .05, p ≤ .001, and p < .0001, respectively). Despite greater LA size, competitive athletes had lower LA stiffness as compared with controls (0.13 ± 0.04 vs. 0.16 ± 0.06, p ≤ .001). In addition, LV stiffness was lower in athletes (0.84 ± 0.27 vs. 1.07 ± 0.46, p ≤ .001). The only independent predictor of LA stiffness was LV stiffness (β = 0.46, p < .0001), while the only independent predictor of LA volume index was LV end-systolic volume index (β = 0.25, p = .002). Competitive athletes showed greater LA size associated with lower stiffness as compared with controls. Thus, LA remodeling in the context of the athlete's heart is not associated with increased LA stiffness. These findings support the benign nature of LA remodeling in athletes, occurring as a physiological adaptation to exercise conditioning.

Differentiating physiology from pathology in elite athletes. Left ventricular hypertrophy versus hypertrophic cardiomyopathy

“…A significantly lower mitral inflow pulsed-wave late diastolic filling (A-wave) peak velocity in the athletes group confirms that in athletes the reservoir and conduit function of the LA predominates. The same effect was observed in the study by D'Ascenzi et al [56] of 150 athletes compared to 90 matched controls.…”

“…The blood flow meets almost no resistance because of good compliance, and the LV filling pressure is low even during strenuous exercise. Generally, the diastolic reserve is large and all the processes of active relaxation, passive filling, and LA contraction are very well organised [55,56].…”

Hypertensive patients with left ventricular hypertrophy have global left atrial dysfunction and impaired atrio-ventricular coupling

“…Henein et al [25] showed that, irrespective of LA morphology, LA volume overload because of mitral regurgitation had a less negative effect on intrinsic LA function than pressure overload because of increased LV filling pressure. Athletes with physiologic LV hypertrophy and normal diastolic function have been shown to have lower booster pump function than controls but similar emptying volume because of a larger LA volume [26] without increased stiffness [27].…”

Left Atrial Enlargement in Young High-Level Endurance Athletes – Another Sign of Athlete’s Heart?

“…Moreover, strain value correlates with atrial fibrosis in paroxysmal and persistent AF (Kuppahally et al, 2010). Left atrial deformation assessment has been previously carried out in male and female athletes (D'Andrea et al, 2008; D'Ascenzi et al, 2014, 2015; Sun et al, 2009). However, to our knowledge, there is no study that has determined normal values of LA strain in a large sample of elite athletes.…”