Table 1.
Echocardiographic parameters in professional soccer players and age matched controls.
Figure 1.
The RR interval and heart rate of age-matched controls and professional soccer players before and following a competitive game.
A: The RR interval was significantly longer (A) and heart rate was significantly lower (B) in soccer players before the game compared to controls (n = 76 persons/group; ***p<0.001 vs. age-matched control; Means ± S.E.M.; ###p<0.001 vs. before game values).
Figure 2.
The QT intervals of age-matched controls and professional soccer players before and following a competitive game.
The QT interval was significantly longer in soccer players before the game (n = 76 persons/group; ***p<0.001 vs. age-matched control; Means ± S.E.M.; ###p<0.001 vs. before game values).
Figure 3.
Frequency corrected QT interval of age-matched controls and professional soccer players before and following a competitive game.
QTc interval calculated with the Bazett formula was not different in soccer players before the game and was significantly prolonged after the game (A). QTc values calculated with the Fridericia and Hodges formulae but not the Framingham formula showed significant difference between groups before the game, and none of the three calculations yielded any difference between before and after game values in soccer players (B, C and D; n = 76 persons/group; Means ± S.E.M.; *p<0.05; **p<0.01; ***p<0.001 vs. age-matched control; ###p<0.001 vs. before game values).
Figure 4.
Short-term beat-to-beat temporal variability of the RR (STVRR) and QT (STVQT) intervals in age-matched controls and professional soccer players before and following a competitive game.
Soccer players had a significantly higher STVRR compared to controls before the game. STVRR was similar to controls in soccer players immediately after the game (A). Poincaré plots illustrating short-term temporal variability of the QT interval at rest in a control individual and in a professional soccer player before the game. Note the shift of QT values to the right and upwards in the soccer player indicating QT prolongation and the increased scattering of QT interval values in the soccer player demonstrating increased beat-to-beat variability of the QT interval (B). Short-term QT variability was significantly higher in soccer players both before and after the game compared to controls but also decreased in players compared to pre-game values (C). (n = 76 persons/group; Means ± S.E.M.; ***p<0.001 vs. age-matched control; ##p<0.01; ###p<0.001 vs. before game values).
Figure 5.
Histograms showing the distribution of the QT interval.
(A) Controls (empty bars) and soccer players before game (full bars) and (B) controls (empty bars) and soccer players after the game (hashed bars). Bin size is 10 ms. (n = 76 persons/group).
Figure 6.
Histograms showing the distribution of short-term beat-to-beat variability of the QT interval (STVQT).
(A) Controls (empty bars) and soccer players before game (full bars) and (B) controls (empty bars) and soccer players after the game (hashed bars). Bin size is 0.5 ms. (n = 76 persons/group).