The body surface area of adult Chinese males was estimated by using paper cast method.56 healthy individuals, aged 18 to 45, coming from thirteen provinces mostly from Hebei and Hubei were used in this study. From the results obtained, the mean body weight, height and surface area were 59.78kg, 168.8 cm and 1.712 m2 respectively. A height-weight equation for estimating body surface area was derived accordingly, i.e. body surface area(m2)= 0.00607H(cm) + 0.0127W(kg)-0.0689. The error of the value calculated from the equation was 0.17% higher than the value actually taken on an average. The percentage of various body regions to the total body surface area was as follows: head, 6.11; trunk (including neck), 29.59; upper arms, 8.09; forearms, 6.41; hands, 4.93; thighs (including buttock), 24.63; calf, 13.29 and feet, 6.95.For convenient use a table for calculation was given.

The purpose of this study was to investigate and analyze the high frequency electrocardiogram (HFECG) for middle-aged and elderly people.138 subjects were chosen in our study.The mean age was 60.38 years.Among them,72.1 per cent were between 50 and 69 years.The results showed that (1) the differences were not significant between male and female groups in the mean number of high frequency notches (HFN).(2) For an increase in high frequency notches in the leads V1 and V2,we should consider the possibility of pathological changes of the anterior medial wall of heart,which was supplied by the dessending rami of the right anterior coronary artery,on the one hand,and it might remind us to pay great attention to posteromedian wall of heart,on the other hand.(3) Looking at all age groups in this study,we preliminarily found that the age peak of ischemic heart disease was between 50 and 70 years,according to the number of high frequency notches in the leads of HFECG.(4) The sensitivity of HFECG for diagnosing ischemic heart disease is 40 per cent higher than that of the conventional ECG.(5) In addition,nine leads were used in this examination,which not only preserved sensitivity of six leads but also could provide a localizing value for the diagnosis of heart disease.

Objective To assess the difference in left atrial properties between elderly and younger control subjects and the role of left atrium remodeling in patients of different ages with atrial fibrillation.Methods A total of 194 patients with non-valvular atrial fibrillation were enrolled from September 2014 to June 2016.Based on age,patients were divided into an elderly group (≥60 years,n=129) and a younger group (＜60 years,n=65).We evaluated remodeling parameters for the left atrium using an Ultrasound Cardiography (UCG) system in 125 elder subjects,together with 64 control subjects.All remodeling parameters were recorded,including left atrial diameter (LAD),left atrial square (LAS),left atrial pressure (LAP) and left ventricular end-diastolic dimension (LVEDD).Results The elderly group had more female patients and more patients with persistent atrial fibrillation.Meanwhile,scores of CHA2DS2Vsc and levels of N-terminal pro-brain natriuretic peptide (NT-ProBNP) were significantly increased in elderly patients (both P＜0.05).Moreover,the elderly group was associated with increased values of LAD and LAS[(39.1±4.4)mm vs.(37.1±5.3)mm,P＜0.01;and(23.3±4.5)cm2 vs.(21.4±4.8)cm2,P＜0.01;respectively],compared with those in the control group.Spearman's correlation analysis showed that LAD,LAS and LAP were all markedly related to age (r=0.213,P＜0.05;r=-0.175,P＜0.05;r=0.170,P＜0.05;respectively),persistent onset of atrial fibrillation (r=0.401,P＜0.05;r=0.446,P＜0.05;r=0.160,P＜0.05;respectively),and impaired heart function,measured by left ventricular ejection fraction (r=-0.4371,P＜0.05;r=-0.403,P＜0.05;r=-0.364,P＜0.05;respectively) and NT-ProBNP (r=0.485,P＜0.01;r=0.483,P＜ 0.01;r =0.293,P＜ 0.01;respectively).Conclusions Left atrial remodeling properties measured by the UCG system in the elderly with non-valvular atrial fibrillation are more serious than those in mid-aged and young subjects.As a convenient and accurate assessment of remodeling parameters,the UCG system is an excellent option for measuring left atrial remodeling in the elderly population.

Objective:To measure the concentration of growth differentiation factor-15(GDF-15)in the serum of patients with atrial fibrillation(AF),to study the correlations between the levels of GDF-15 and different factors including basic clinical information,biochemical examinations,and atrial structure,and further to explore the association between GDF-15 and AF types and structural remodeling.Methods:AF patients who were admitted to the ward of the Department of Cardiology at Peking Universi-ty Third Hospital between October 2017 and October 2019 were prospectively enrolled.Patients admitted to the ward at the same time with sinus rhythm and no prior AF history were enrolled in the control group.Clinical information and blood samples of the patients were collected.Enzyme-linked immunosorbent as-say was used to measure the concentration of GDF-15.SPSS 23.0 was used for statistical analysis.Results:In the study,156 AF patients(64 persistent AF and 92 paroxysmal AF)and 38 patients of the control group were included.Serum GDF-15 levels in the AF group were significantly higher than in the control group[1 112(723,1 525)ng/L vs.697(499,825)ng/L,P＜0.001].Serum GDF-15 levels in the persistent AF group were significantly higher than in the paroxysmal AF group[1 140(858,1 708)ng/L vs.1 090(662,1 374)ng/L,P=0.047].The area under the curve(AUC)of serum GDF-15 levels for prediction of AF was 0.736(95％CI:0.651-0.822,P＜0.001).The cut-off value was 843.2 ng/L with a sensitivity of 68.2％and a specificity of 78.9％.The AUC of serum GDF-15 levels for prediction of persistent AF was 0.594(95％CI:0.504-0.684,P=0.047).The cut-off va-lue was 771.5 ng/L with a sensitivity of 82.8％and a specificity of 35.9％.Spearman rank correlation analysis showed that the serum GDF-15 levels were positively correlated with age(r=0.480,P＜0.001),left atrial pressure(LAP,r=0.300,P＜0.001),and also negatively correlated with left atrial appendage flow velocity(LAAV,r=-0.252,P=0.002).Multiple linear regression analysis showed that age and LAP affected the GDF-15 levels significantly(P＜0.05).Logistic regression analysis sug-gested GDF-15(OR=1.002,95％CI:1.001-1.003,P=0.004)and left atrial diameter(LAD,OR=1.400,95％CI:1.214-1.616,P＜0.001)were independent predictors of AF.Conclusion:Serum GDF-15 levels are higher in AF patients.Meanwhile,serum GDF-15 levels are higher in persistent AF patients than paroxysmal AF patients.GDF-15 is associated with AF and atrial structural remodeling.