Influence of cardiac changes on QT dispersion in strength - trained athletes

Previous studies have reported that practice of intensive sports may lead to cardiac changes, including left ventricular hypertrophy. QT dispersion is a measure of inhomogeneous repolarization of myocardium and it can be used as an indicator of arrhythmogenicity.

The aim of this study was to determine the influence of cardiac changes on QT dispersion in strength - trained athletes.

The study involved 125 male subjects: 79 strength - trained athletes (powerlifters, body-builders) and 46 healthy subjects without sport activities. There was no age difference between the two groups of subjects. In all subjects echocardiographic examination were performed. Diastolic parameters were measured by Doppler analysis and tissue Doppler imaging (TDI). Transmitral flow of early (E) and late (A) wave peak velocities, isovolumetric relaxation and deceleration times were obtained. From TDI we calculated peak velocity of systolic (s’), early (e’) and late (a’) diastolic waves. From standard ECG corrected QT dispersion (QTdc) was calculated.

Strength - trained athletes had significantly higher values of left ventricular mass (257.2 ± 28.2 vs 186.5 ± 27.9 g; p<0.001), intraventricular septum thickness (12.6 ± 0.9 vs 10.0 ± 0.6 mm; p<0.001), thickness of the left ventricle posterior wall (11.6 ± 0.6 vs 9.4 ± 0.9 mm; p<0.001), left ventricular ejection fraction (68.8 ± 1.8 vs 65.82 ± 3.2 %; p<0.001), left atrium diameter (41.1 ± 3.1 vs 37.3 ± 2.2 mm; p<0.001), E/A ratio (1.62 ± 0.24 vs 1.50 ± 0.21; p<0.005), e’/a’ ratio (1.76 ± 0.32 vs 1.58 ± 0.25; p<0.001) and QTdc (58.2 ± 10.6 vs 48.1 ± 8.3 ms; p<0.001), and significantly lower values of E/e’ ratio (5.46 ± 0.82 vs 5.87 ± 0.90; p<0.01), compared to sedentary controls. In strength - trained athletes, a significant correlation was found between QTdc and left ventricular wall thickness and left ventricular mass (p<0.01 for all parameters).

The study showed that strength - trained athletes have a higher values of left ventricular mass, left ventricular wall thickness and better left ventricular systolic and diastolic function compared to sedentary controls. Strength - trained athletes have higher values of QTdc compared to sedentary controls, which correlates with left ventricular wall thickness and left ventricular mass.