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DYNAMICS OF INDICATORS OF REPOLARIZATION OF THE LOAD IN YOUNG ATHLETES IN ELITE SPORT

L. М. MAKAROV, B. N. KOMOLIATOVA, N. N. FEDINA CENTER FOR SYNCOPE AND ARRHYTHMIAS IN CHILDREN AND ADOLESCENTS OF FEDERAL MEDICO-BIOLOGY AGENCY OF RUSSIA, MOSCOW, RUSSIA
The aim of study was assessment changes of repolarisation parameters in young elite athletes. Were investigated 425 elite athletes aged 15 to 17 years (16±1,4 years), members of the national teams of Russia in a variety of sports: basketball (n=69), baseball (n=29), water polo (n=37), volleyball (n=42), wrestling (n=35), handball (n=43), alpine skiing (n=23), rowing (n=21), skating (n=8), athletics (n=11), skiing (n=12), sailing (n=8), swimming (n=4), gymnastics (n=18), boxing (n=37), weightlifting (10), soccer (n=29), hockey (n=10). The control group consisted of 26 healthy adolescents 15,5±1,4 years old who are not involved in competitive sports. All respondents were examined of a cardiologist, and all were record 12-lead rest ECG in the supine and standing, echocardiography, bicycle aerometry by method PWC170. Indicators of repolarization were evaluated by automatic analysis microvolt T-wave alternans (MMA method), the absolute values qT and qT c intervals (system Cardiosoft 6.5 V 6.51 and GE Healthcare, USA). All parameters were measured at the start and end of the test and in after each step the load on the 2-nd and 4-th minutes of recovery; «qT dynamics» , which is carried out using a sample of the equation linear regression estimate of the parameter slope qT/RR. The maximum values of the qTc in athletes and healthy individuals not involved in sports, recorded during start of load and did not exceed 460 ms for athletes during exercise is characterized by higher values of «qT dynamics» (steep slope qT / RR) – (steep slope or hyperadaptation qT interval for heart rate): slope qT/RR 0,29 ± 0,05 (athletes) vs 0,23 ± 0,03 (not athletes), p <0,001. That may play a role in the evaluation of adaptation of the cardiovascular system to stress and to identify levels of physical performance in athletes.
Keywords: 
interval qT in athletes, stress test, «qT-dynamicity» and microvolt T-wave alternans in athletes.