Lack of association between obesity and left ventricular systolic dysfunction

Previous studies have demonstrated that obesity is one of the risk factors for congestive heart failure (CHF). By analyzing a large database, we investigated any association between body mass index (BMI) and left ventricular (LV) systolic dysfunction.

We retrospectively analyzed 24,265 echocardiograms performed between 1984 and 1998. Fractional shortening (FS) and BMI were available for 13,382 subjects in this cohort which were used for data analysis. FS was stratified into four groups: (1) FS > 25%, (2) FS 17.5-25%, (3) FS 10-17.5%, and (4) FS < 10%. Furthermore, we also used final diagnosis that was coded by the reading cardiologist as mild, moderate, and severe LV dysfunction separately for data analysis. BMI was divided into four groups: BMI < 18.5 kg/m(2) (underweight), 18.5-24.9 kg/m(2) (normal), 25-30 kg/m(2) (overweight), and >30 kg/m(2) (obese).

There was no association between different BMI categories and LV systolic function. The prevalence of mild, moderate, or severely decreased LV function (based on FS or subjective interpretation of reading cardiologists) was equally distributed between the groups. Obese patients (BMI > 30%) had normal FS of >25 in 16.9%, mildly decreased FS in 18%, moderately decreased FS in 18.4%, and severely decreased FS in 20.1% P = ns.

Our study is consistent with previous trials suggesting that obesity is not related to systolic LV dysfunction. The underlying mechanism for the occurrence of congestive heart failure in obese patients needs further investigation.