The Research On Male Students' Left Ventricular Systolic Function Integrated Assessed By Using STI Index

Purpose:This research is drawn up to experimentally study cardiac STI indicators features of male college students who major in physical training, economic management and human movement science in a resting state, discontinuous increasing load condition and recovery period in order to comprehend the left ventricular systolic function of different kinds of population in different conditions, and make a quantitative rating standard of the college student's left ventricular systolic function in condition of rest, discontinuous increasing load, and provide the theoretical reference basis for selecting athletes, monitoring and assessing functions and formulating the athletic training plans.Methods:The experimental subjects include:60 students from Xi'an Physical Education University who major in physical training, economic management and human movement science, who are divided into two groups:Group I is 30 ordinary male students in grade 2009 majoring in human movement science and economic management; Group II is 30 male students from Department of Gym majoring in endurance events. All the students are sure to have no cardiac illness. Test the value of STI in rest time by applying the synthetic Tester of Cardiac information model MCA-3C, and then complete the exercises of increasing load on dynamometer bicycle. The sports-load begins from 60W (the rotational speed is 60 revolutions per minute).Every rank of load lasts 3 minutes, the higher rank of load will begin after increasing 30W.There is 1 minute between every two grades of load for gathering the value of STI until they have completed 180W. When the exercise is over, immediately measure STI in the recovery period of the 1st,3rd,5th,7th minute.Results:1. At resting state, the index HR, R-R, LVET, EMT, MST, EML of STI present very significant differences between group I and groupⅡ(P< 0.01), and the value of groupⅡsubjects are greater than that of the groupⅠ's subjects. The index PEP of groupⅡare higher than that of groupⅠ's (P< 0.05). Other indexes of the two groups don't present significant differences.2. During the process of discontinuous increasing load, the HR, R-R, and LVET under the load of 60W,90W and 120W of the groupⅡof volunteers are higher than that of the groupⅠ, and there exists significant difference between these two groups(P<0.01); the PEP under the load of 90W and 120W between the two groups of volunteers is significantly difference(P<0.05); when the load is 60W and 90W, the EMT between them has very significantly difference(P<0.01), and when the load is 120W, the EMT of the groupⅡof volunteers is higher than that of the groupⅠ; the MST under the load of 60W and 90W of the two groups of volunteers is obviously different(P<0.05); the EML under the load of 90W and 120W of the two groups of volunteers is obviously different(P<0.05); both the EMT and MST of the groupⅡare higher than that of the group I3. At the 3rd,5th, and 7th minute of the recovery phase, the HR and R-R of the two groups are significantly different(P<0.05); at the 5th and 7th minute, the LVET and EMT of them are significantly difference; at the 1st,3rd,5th, and 7th minute, the EMT of them is very significant difference (P<0.01). Besides, the R-R, LVET, EMT and EML of the groupⅡare all higher than that of the group I except HR.4. In STI indexes reflecting Left Ventricular Systolic Function, after cluster analysis and researching on every index, HR, LVET, PEP, PEP/LVET, MST, EML and ICT are sensitive indexes of overall evaluating Left Ventricular Systolic Function in the rest and the load 120W conditions.Conclusion:1. Make sure of the weight coefficient of every index when overall evaluating the left ventricular systolic function under the rest and the load 120W conditions using the factor loadings and the contribution rate obtained by using principal component analysis to describe the degree of importance in comprehensive evaluation of the indicators of left ventricular systolic function, and according to it, draw up a composite score formula in the rest condition and under the load of 120W: In the rest condition:Y1=0.11X1+0.14X2+0.14X3+0.12X4+0.17X5+0.18X6+0.14X7 Under the load of 120W:Y2=0.13X1+0.14X2+0.14X3+0.11X4+0.12X5+0.18X6+0.18X72. This research adopts percentile method to make an assessment standard to reflect every index of left ventricular systolic function sensitively in the rest and the load 120W conditions, and give the grade evaluation of the synthetically score using percentile method, and the overall evaluation of left ventricular systolic function can be more intuitive and quantitative.