Abstract 3356: Does Severe Obesity Cause Progressive Impairment of Left Ventricular Systolic Function?

Background: Obesity is associated with an increased risk of developing heart failure. Based on cross sectional studies, it has been hypothesized that the duration of obesity is the key factor leading to impaired cardiac function. However, longitudinal data to confirm this hypothesis are not available. Methods: We prospectively studied 62 severely obese patients at baseline, 2 and 5 years after randomization to nonsurgical therapy (NonSurg, n = 25) or Rouxen-Y gastric bypass surgery (GBS, n = 37). Echocardiography was used to measure left ventricular (LV) size and ejection fraction (EF). Results: At enrollment, the mean BMI was 46±9 and the mean age was 47±11 years (range 25– 66). GBS subjects lost 96± 26 vs. 6±18 lbs at 2 years and 78±42 vs. 17±42 lbs at 5 years compared to NonSurg (p<0.0001 for both). At baseline LVEF was not different between GBS and nonsurg (67±9 vs. 64±8%) and it did not change at 2 years (64±9 vs. 63±9%) or 5 years (63±9 vs. 63±10%). LV diastolic dimension did not change over time in control (4.3±1.0 vs. 4.2±0.6 vs. 4.5±0.3) or GBS patients (4.4±0.6 vs. 4.3±0.7 vs. 4.4±0.4). Stratifying the entire group by quartiles of age or duration of obesity (quartile 1 avg duration = 16 years, quartile 4 average duration = 56 years), we found no evidence of time-dependent changes in LV size or function. Conclusion: In this, prospective study of severely obese patients we found no evidence of progressive changes in LV size or EF over a period of 5 years. Moreover, we find no relationship between age or duration of obesity and LV size or LVEF. These data argue strongly that other factors such as the development of coronary disease are the most likely causes of heart failure in obese patients.