China's Sichuan Province, Tibetan, Han Reference Cardiac Function Parameters Investigation And Analysis

Objectives1.To measure the values of main heart function parameters of the healthy population aged 10 to 70 years old in the given areas of Sichuan Province,China and to provide the data for understanding and appraising heart functions of Sichuan Tibetan people living on Tibetan plateau and Sichuan Han people living on plains in the future.2.To describe the pattern of distributions of the heart function parameters by age and to describe the changes of the values of heart-function parameters with the changes for height, weight and BMI,respectively.3.To explore the effects of BMI and smoking on the eight heart-function parameters.MethodsA cross-section study was conducted for the research in 2008.A group of 2870 healthy residents aged 10 to 70 years old were randomly chosen for the study in Songpan county living by Tibetan people,and Xinjin county and Qionglai county living by Han people in Sichuan Province. The eight main heart function parameters were measured by BioZ.com digital noninvasive hemodynamic monitor,produced by the United States Car-diodynics company.Height and weight were measured by height measuring device and lever scale.Mean±standard deviation was used for the analysis of the data with normal distribution.Also percentile values by age and gender were calculated for every one of the heart function parameters. And t test was used for the comparison of the mean difference between different gender groups for same age group.The covariance analysis was used for the comparison of the means of two data groups in order to control the influence of the covariates,height,weight and BMI.ANOVA was used to analyze the data related to multiple group comparison.P＜0.05 was determined as statistically significance.ResultsThe results showed that the average heart rate of males under 30 years old gradually decreased, from 87 times/min of 10～14-year-old group to 75 times/min of 20～29 year old group,and after age of 50 years it gradually increases to 82 times/min of 60～70 year old group.Similarly, decreasing first but increasing later,the mean value of systemic vascular resistance(SVR) of teenagers was 1100 dyn/sec.cm~5,however,higher than that of mid-aged groups,and it increases gradually to 1200 dyn/sec.cm~5 after age of 50 years.The mean of male cardiac output(CO) and cardiac index(CI) increased gradually before 20 year old group,and reached its peak level of 6.50 L/min and 3.70 L/min·m~2,respectively,and it maintained the level for next two groups,then slowly decreasing after age of 50 years,and continuing to a level of 5.50 L/min and 3.20 L/min·m~2 of the 60-70 age group.The means of male stroke volume(SV) and stroke index(SI) demonstrated a similar change trend.Before age 30,the means of male subjects gradually increased from 60.00ml/min and 43.00 ml/beat·m~2 of the 10-14 year old group to 75ml/min and 50.00 ml/beat·m~2 of the 20-29 year old group,respectively,but it also decreased to 60ml/min and 45.00 ml/beat·m~2 of the 60-70 year old group after age of 50 years.The means of systolic blood pressure(SBP) and diastolic blood pressure(DBP) for male groups slowly increased with age increasing.It increased from 115mmHg and 70mmHg of 10-14 age group to 127mmHg and 85mmHg of the 70 year old group;respectively.The difference of the means of heart function parameters between male group and female group becomes more obvious after age 14,and the main indicators of cardiac function(CO,CI,SV,SI) of male group performed a higher means than those of female group in each older age group.HR means of the female groups for both age groups(15～19 years and 30～50 years) were higher than that of male groups.Also,The same pattern was showed in SVR.However,the SBP means of female groups were lower than that of male groups after age 14 in the Tibetan peoples.The comparison of the mean difference between both group for male and female was not showing a result of statistically significance.The mean value for almost each parameter showed a similar change trend for both Tibetan people and Han people.It was found that a statistically significant difference was demonstrated in the comparison of mean differences of heart function parameters between obesity,overweight and normal BMI groups or between smokers and non-smokers.ConclusionThis study collected data about the main heart function parameter measurement of Tibetan people living on Tibetan plateau(3000～3500 meters above sea level) and the Han people living on plains(400～500 meters above sea level) in Sichuan Province,China.The study describes the mean value,standard deviation,95%CI,maximum,and minimum values of each parameter for both groups of recruited subjects.Also,the tables by percentile value were made to describe the parameters.The features of each parameter change relative to age were observed,and it was demonstrated that there were statistically significant difference of parameter mean value between genders in many age groups.The results of study suggested that BMI and smoking be important influence factors on the heart function parameters.It is recommended that the reference values for the heart function parameters of normal Chinese people are developed according to age and gender of peoples,and the BMI influence on the parameters is paid attention to,and non-smokers subjects are ruled out.