Results:
Of 520 invited individuals, 394 (76%) met for examination. After
exclusions, 57 athletes with paroxysmal AF, 87 athletes without AF, 88
non-athletes without AF, and 61 non-athletes with paroxysmal AF were
included (Figure 1).
Baseline characteristics: All participants were men, with a mean
age of 70.7 ± 6.7 years. Athletes with and without AF reported a median
of 40-50 years of performing regular endurance exercise and a median of
16 completed annual Birkebeiner XC-races. Eighty-six participants had
never practiced regular endurance exercise, whereas 49 participants had
practiced regular endurance exercise for 1 to 20 years, 43 participants
for 20 to 40 years, and 115 participants for >40 years.
Almost 80% of the athletes still participated in regular endurance
exercise at the time of examination. Athletes had a very low comorbidity
burden, a lower BMI and a lower resting heart rate than non-athletes.
Blood pressure was similar between all four groups. Individuals with AF
were taller than those without AF. The AF burden was low in both AF
groups, with more than three out of four individuals experiencing
paroxysms of AF less than once a month. While a higher proportion of
athletes had performed AF ablation, the use of antiarrhythmic drugs was
higher among non-athletes (Table 1).
Echocardiographic parameters: LA echocardiographic parameters are
presented in Table 2, and LV echocardiographic values are presented as
supplemental material (Table S1). There was no significant interaction
between athletic status and AF status regarding atrial parameters. LA
size was associated both with athletic status and AF status. SD-TPS
stated in ms was associated with AF status but not athletic status. When
correcting SD-TPS by the R-R interval, we found SD-TPS (%) to be
associated with both athletic and AF status. LASr, LAScd, and LASct were
lower in the AF groups regardless of athletic status. As opposed to
LAVImax, we could not identify any significant trend
between years of performing endurance exercise and SD-TPS in individuals
without a history of AF (p=0.893) (Figure 3).
SD-TPS remained significantly associated with AF after adjusting for
height, weight, CHA2DS2-VASc score,
LAVImax, GLS, and QRS width in all participants and the
athletic group alone (Table S2 and S3). However, SD-TPS did not remain
significantly associated with AF in athletes when LASr was included in
the model (p=0.06) (Table S4). Hence, in a hierarchical logistic
regression model, SD-TPS did not add independent incremental value in
identifying individuals with AF on top of clinical characteristics,
CHA2DS2-VASc score, QRS width, standard
echocardiographic values, and LASr (Figure 4).
Athletes had larger left ventricles and slightly lower GLS and E/e‘ than
non-athletes. There were no significant interactions between AF and
athletic status regarding LV values except for LV mass index. GLS was
not significantly affected by AF status.