Left Ventricular Hypertrophy and Asymptomatic Cardiac Function Impairment in Chinese Patients with Simple Obesity using Echocardiography

BACKGROUND Simple obesity in China is rising rapidly and causing increasing concern. The objectives of our study are to investigate cardiac structure and function in individuals with simple obesity and to analyze the effect of BMI on left ventricular structure and function. METHODS Between January 2012 and July 2014, echocardiography was performed in 361 consecutive patients visiting the outpatient echocardiography center for a health examination or cardiac evaluation before a weight loss operation in our hospital. Echocardiographic indices, waist-to-hip ratios, BMI, and metabolic markers were evaluated. We analyzed these data using Student's t test (normally distributed) or a nonparametric test (not normally distributed) for continuous variables and chi-square test for categorical variables. Multivariate correlation and regression analysis were conducted for comparisons. RESULTS The study sample was divided into three groups: a normal/overweight group (BMI < 28.0 kg/m(2)), a mildly/moderately obese group (BMI 28-39.9 kg/m(2)), and a severely obese group (BMI ≥ 40 kg/m(2)). There were no significant differences in clinical and laboratory characteristics among the groups, except for BMI and waist-to-hip ratio. The severely obese group had a higher left ventricular end diastolic diameter (LVEDD; p < 0.01) and lower left ventricular ejection fraction (LVEF; p < 0.01) than the mildly/moderately obese group, which had a higher LVEDD and LV mass index (LVMI) than the normal/overweight group. BMI correlated well with LVEDD, left ventricular posterior wall thickness at end-diastole (LVPW), LV mass, LVMI, and E/e'. In addition, age was significantly associated with some echocardiographic parameters, including left atrial dimension (r = 0.366, p < 0.01), LVPW (r = 0.347, p < 0.01), interventricular septal thickness at end- diastole (r = 0.351, p< 0.01), and E/A (r = -0.47, p < 0.01). CONCLUSIONS Simple obesity caused cardiac structural changes, including LV hypertrophy and LV enlargement, and severe obesity resulted in asymptomatic LV systolic and diastolic function impairment.