The association between higher BMI and improved outcomes was seen in patients with HFrEF and with HFpEF.201 A meta-analysis of 9 obser- vational studies of BMI and outcomes in HF (n=28209 HF subjects) revealed that overweight (BMI, 25.0 9.9 kg/m2 ) was associated with reduced relative risk of cardiovascu- lar mortality of 0.81 (95% CI, 0.72 0.92) and that obesity ) was associated with an even lower risk Lastly, the pro- tective effect of obesity was also noted in patients with acute decompensated HF; patients in the highest quartile of BMI had the lowest risk of in-hospital mortality in the Acute Decompensated Heart Failure National Registry.207 BMI, because of its general acceptance and ease of use, is the primary tool for assessing obesity or body fatness in clinical practice; however, BMI does not dis- criminate between fat and lean mass and furthermore cannot assess the distribution of body fat.204,208 Waist circumference has been shown to be associated with im- proved outcomes in both men and women with advanced Furthermore, in a study of patients with ad- vanced HF that assessed body fat percentage using the skin-fold technique, patients with HF in the highest body fat quintile (mean, 37.7%) had the lowest rate of death and urgent heart transplantation (5%) compared with an event rate of 22% in the patients in the lowest body fat quintile (mean, 16.4%).211 A study of community HF clinic patients in the United Kingdom assessed multiple measures of body mass, including weight, height, body surface area, BMI, and bioelectrical impedance data, and found that the larger the patient s size was, the lower the risk of mortality was. In a multivariable model, the single best predictor of outcome was body surface area212 Epicardial adipose tissue is a visceral fat depot of variable volume around the heart that is biochemically active in terms of free fatty acid release and the produc- tion of adipokines.213 In the general population, epicar- dial adipose tissue is known to be associated with meta- bolic syndrome and coronary artery disease risk.210,214 However, preliminary studies have demonstrated low epicardial adipose tissue in patients with HF compared with healthy subjects.215 Furthermore, a recent study found low epicardial adipose tissue in HF to be associ- ated with increased HF mortality, possibly representing a novel component of the obesity paradox in HF.212,216 Taken as a whole, these data suggest that higher body mass, whether fat or lean mass, is associated with im- proved outcomes in the syndrome of HF. 