Left atrial dyssynchrony in veteran endurance athletes with and without
paroxysmal atrial fibrillation
Abstract
Background: Prolonged endurance exercise is associated with an increased
risk of atrial fibrillation (AF) in men. Left atrial (LA) dilation is a
marker of pathological atrial remodeling and associated with AF in the
general population. In athletes, however, atrial dilation is part of a
physiological response to exercise, and functional parameters may help
separate physiological from pathological atrial remodeling in this
group. LA mechanical dispersion (LA MD) is a novel marker of LA
mechanical dyssynchrony associated with AF in the general population.
The associations between prolonged endurance exercise, LA MD and AF are
yet to be investigated. Purpose: To investigate LA MD in male veteran
athletes who had regularly participated in an annual 54-kilometer
cross-country (XC) ski race in Norway with and without paroxysmal AF and
to investigate the ability of LA MD to identify veteran athletes with
paroxysmal AF. Methods: Two hundred and ninety-three men from four
groups, veteran XC skiers with (n=57) and without (n=87) AF, and men
from a non-athletic population with (n=61) and without AF (n=88)
underwent an echocardiographic exam while in sinus rhythm. Using
speckle-tracking echocardiography, LA strain was measured in each of the
six atrial segments in an atrial-focused apical four-chamber view. We
defined LA MD as the standard deviation of time-to-peak strain (SD-TPS)
and report the average from three consecutive loops. Results: XC-skiers
(mean age 70.9 ± 5.7 years) reported an average of 40-50 years of
regular endurance exercise and an average of 16 completed annual
Birkebeiner XC ski races. LA volumes were associated with both AF and
athletic status (p<0.001). SD-TPS was associated with AF
(p<0.001), but not with athletic status (p=0.173). We found no
significant trend between years of endurance exercise and SD-TPS in
individuals without AF (p=0.846). SD-TPS did not add incremental value
in identifying athletes with AF in addition to clinical markers, QRS
width, LA volume, and LA reservoir strain (p=0.056). Conclusion: LA MD
was associated with paroxysmal AF regardless of athletic status.
However, it was not associated with years of performing endurance
exercise, suggesting LA MD could be a promising marker of pathological
atrial remodeling in endurance athletes, less affected by physiological
exercise-induced atrial remodeling than absolute volumetric
measurements. We found no incremental value of LA MD in identifying
veteran athletes with paroxysmal AF when LA reservoir strain was
included in the model.