Association of ECG early repolarization phenomena and “T-infantile” with autonomic regulation of the heart rhythm in young athletes

Abstract

The incidence of autonomic disorders in athletes varies widely from 6.2 % to 36.5 %. With the improving sport qualification, the frequency and severity of autonomic dysfunction increase. Various ECG phenomena, including SEVR and “T-infantile” are associated with a type of autonomic tone. Moreover, ANS dysfunction does not determine the genesis, but only contributes to the manifestation of these syndromes signs. The association between the ECG phenomena and autonomic dysfunction nature, age and gender of athletes remains an open question. The purpose of this work was to study the incidence of juvenile T-wave and SEVR, their association with the autonomic regulation of heart rate in young athletes in the age range between 6 and 17 years. Materials and methods. An electrocardiographic study and 5-minute recordings of the heart rate variability were carried out in 3720 children and adolescents aged between 6 and 17 years, of them 74.6 % were boys (n = 2774) and 25.4 % were girls (n = 946), engaged in various sports. The study results. The “T-infantile” phenomenon was detected in 1.5 % (56/3720) of athletes, among them 1.07 % (40) were boys and 0.43 % (16) were girls. In five (12.5 %) athletes, “T-infantile” was combined with incomplete right bundle branch block, in 3 (7.5 %) – with short PQ syndrome, and in one (2.5 %) – with SEVR. In addition to the ECG signs of “T-infantile”, three (18.75 %) athletes additionally had incomplete RBBB, and also short PQ syndrome was detected in one athlete (6.25 %). A comparative analysis of HRV indices in boys and girls with the “T-infantile” phenomenon showed that in boys, the D value was significantly higher, reflecting the vagal regulation activity of the heart rhythm (0.403 ± 0.028 s versus 0.311 ± 0.025 s, P = 0.019). When assessing the autonomic state according to R. M. Baevsky, it was found that 40 % (n = 16) of male athletes with T-infantile ECG phenomenon had an increased parasympathetic nervous system tone, 50 % (n = 20) had normal ANS tone, and 10 % (n = 4) had an increased sympathetic nervous system tone. In girls, there were 31.25 % (n = 5) with increased PNS tone, 50 % (n = 8) with normal ANS tone and 18.75 % (n = 3) with increased SNS tone, respectively. Conclusions. Early repolarization syndrome and “T-infantile” are more common in case of increased parasympathetic nervous system tone rather than in other variants of autonomic tone. A combination of parasympathetic overactivity with these ECG phenomena is observed mainly in males. The phenomenon of “T-infantile” can be combined with incomplete right bundle branch block in young athletes of both sexes.

Keywords

• “т-infantile”
• young athletes
• autonomic balance