The Warning Study Of Exercise-induced Cardiac Injury In A Military Region For Training Staff

With improving the physical demands of the soldiers military training, the physical fitness should be enhanced by strengthening physical training. However, some studies have shown that high-intensity exercise training can lead to myocardial injury and necrosis, and even malignant arrhythmia, heart failure and sudden cardiac death. High- intensity training can lead to heart damage manifested as different clinical types. Abnormal changes in ECG,cardiac enzymes and echocardiography are their strongest evidences which should be paid attention to.This study observed the changes of three aspects including Holter monitoring, cardiac injury markers and echocardiography related indicators before and after heavy load training to explore whether new recruits occured myocardial damage by training exercise stress or not, and provide basis for prevention and treatment of injuries.1. Changes in exercise-induced cardiac injury by Holter related indicators.Methods 150 health male volunteers were selected, whose age was(20±3) years old.Using the electrocardiogram to record 24 hours. The electrocardiogram was detected for24 hours the day before the training, then the electrocardiogram was tested again immediately after the training which was required to complete in 15 minutes, and the data was analyzed offline by the specialist. Results The deceleration capacity(DC) of rate(11.71±3.41 vs 12.65±3.33) reduced more obviously(P<0.05). The occurrence rate of ventricular arrhythmias and ST segment depression were significantly higher than before training, but there was no changing in the atrial arrhythmias. Conclusion High-intensity military training could change cardiac autonomic nervous system, induced all types of arrhythmias and myocardial ischemia, and leaded to heart damage.2.Warning of exercise-induced cardiac injury by myocardial injury markers related indicators.Methods A total of 200 male recruits registered for one month were randomly selected and having no history of structural disease. The levels of cardiac troponin T(c Tn T), B-typenatriuretic peptide(BNP), creatine kinase(CK), creatine kinase isoenzyme(CK-MB) were measured before and after the 3 km training, The indexes of two groups were compared.Results The indexes related to heart function such as c Tn T, CK-MB/CK, Mb are more higher than those before 3 km military training(P<0.05). When the cut-off value of c Tn T is set at 0.0025, we could obtain the maximum Youden index, which equal to 0.469, and the sensitivity is 87.5%. When the cut-off value of CK-MB/CK is set at 6.5%, we could obtain the maximum Youden index, which equal to 0.288, and the sensitivity is 65.8%. Conclusion Changes in serum creatine kinase and troponin and other indicators show that high-intensity exercise training induces minor damage on cardiac military. CK-MB/CK and c Tn T reflect diagnostic accuracy of myocardial injury, and reflect the early myocardial damage preferably.3. Changes in cardiac structure and function after high-intensity training.Methods Do the echocardiography for a random sample of 40 recruits who was trained3 km before training, immediately after training and after training of 6 months, then compare the cardiac structure and function index. Results Compared with before training,left atrial diameter(31.25±2.64 vs 29.93±2.59) increased significantly after training(P<0.05). Compared with before training, E/A(1.73±0.27 vs 1.90±0.24) decreased significantly after training(P<0.05),but there is no significant difference between before training and after training of 6 months. Conclusion High-intensity training resulted in changing of the heart structure and function. Left atrial diameter of compensatory enlargement and left ventricular diastolic function slightly reduced after six months of systematic training, left atrial diameter and left ventricular diastolic function changed adaptively.