Effects of Weight Loss on Pericardial Fat and Left Ventricular Mass Assessed with Cardiac Magnetic Resonance Imaging in Morbid Obesity

Background: Obesity is a risk factor for cardiovascular disease and mortality. Significant weight loss has beneficial effects on left ventricular structure, in particular on regression of left ventricular hypertrophy (LVH). We therefore evaluated the consequences of significant weight loss on left ventricular morphology, hemodynamics and pericardial fat. Methods: We performed volumetric cardiac magnetic resonance (CMR) imaging before and after significant weight loss due to laparoscopic adjustable gastric banding (LAGB). CMR was used to measure cardiac mass, volume and function, as well as to quantify pericardial fat. Results: Eleven patients (age 40.5 ± 10 yrs, body mass index 42.5 ± 3.9 kg/m) underwent CMR imaging before and a median 15.4 months after gastric banding. The BMI declined by 9.3 ± 3.3 kg/m (p < 0.001) with an average excess weight loss (EWL) of 54.7% ± 23.6%. The left ventricular mass (LVM) decreased from 130.0 g ± 35.4 g to 117.0 g ± 34.9 g (p = 0.003), whereas the left ventricular chamber volumes and systolic function remained unchanged. After LAGB surgery the pericardial fat volume was reduced by 34.4 ml ± 22.1 ml (p < 0.001). There was a significant correlation for change in pericardial fat volume with change in LVM (R = 0.67, p = 0.024), with no relationship between percentage of EWL and change in LVM (p = 0.49). Discussion: Significant weight loss in obesity is accompanied by a marked regression of LVH, with no apparent change in cardiac volume or function. The local effect of a diminished amount of pericardiac fat tissue may be more important than absolute weight loss with respect to the regression of LVH in obesity.