Effect of Isolated Obesity on Left Ventricular Function and Structure: A Single-Center Experience

Background and objectives Obesity can increase cardiac mass and affect cardiac performance independently from other risk factors. Several studies have identified an association in patients who already have comorbidities, however, few studies focused on obesity as an isolated risk factor. This study aimed to assess the associations between isolated obesity and heart morphological and functional characteristics. Methods This was a cross-sectional study that recruited 114 patients referred for echocardiographic study in King Faisal Cardiac Center. Adult patients who had a body mass index (BMI) above 25 kg/m2 were included, while patients with comorbidities such as hypertension, diabetes mellitus, dyslipidemia, or those who use medications for chronic diseases were excluded from this study. Variables of interest that we collected were age, gender, weight, BMI, and those related to morphological and functional changes in the heart including left ventricular mass index (LVMI), LV end-diastolic volume, and left ventricular ejection fraction (LVEF). Results Most of the study participants (63.8%) were class II or class III obesity and about 80% were males. The mean ± SD of LVEF was 55.7% ± 2.8%, while the mean of the left ventricular mass index was 28.5±5.84. The mean of LV end-diastolic volume index (LVEDVI) was slightly higher among males than females (48.8±11.6 versus 46.4±11.7 ml/m2), however, this difference was not statistically significant (p-value= 0.395). There was no correlation between BMI and LVMI in females (R - 0.226, R2 0.05, P-value 0.37), while the LVMI was found to have a negative correlation between BMI and male gender that was significant (R - 0.292, R2 0.09, P-value 0.0052). It was found that there is no correlation between LVEF and BMI for males and females (male= R 0.093, R2 0.032, P-value 0.093; female= R 0.172, R2 0.029, P-value 0.434). With regards to the LVEDVI, there was a negative correlation between higher BMI and male gender that was significant (male= R - 0.396, R2 0.157, P-value 0.0001) while it was not significant in females (R -0.0298, R2 0.0009, P-value 0.893). Conclusions We have found that cardiac function is not affected by isolated obesity. However, indexed cardiac parameters like LVM and LV end diastolic volume were negatively correlated with higher BMI and positively correlated with relative wall thickness (RWT) only in males. This negative correlation might be one of the triggers to the development of obesity-induced cardiomyopathy.