Myocardial Mass in Morbidly Obese Patients and Changes with Weight Reduction

Cardiac weight was determined at autopsy in 27 morbidly obese, but otherwise healthy men (mean weight 168 kg) and women (mean weight 138 kg) who died suddenly, prior to, or shortly after gastric restriction operations for relief of obesity. They had lost no weight. Post-mortem examination revealed no cardiac or other pathology explaining the cause of death. Cardiac weight was also measured in 25 men and women of equivalent baseline weight and body mass index who, after operation, subsisted on a hypocaloric diet for 3-4 months after operation, but then died suddenly. Mean weight losses of this latter group were 45.8 kg in men and 32.9 kg in women. No cardiac abnormalities and no organic causes of death were found at autopsy. Decreases in heart weight were calculated. The baseline measurements demonstrated that cardiac weight in the healthy obese rose with increasingly severe obesity in both sexes, but the increase tended to lessen with more extreme obesity. The generally quoted figures of cardiac weight as a fraction of body weight are 0.043 and 0.040% for men and women, respectively. In the group of morbidly obese men, cardiac weight was 0.035% of body weight or 16% lower than predicted. In morbidly obese women, cardiac weight was 0.030% of body weight or 25% lower than predicted. In men, a 28% body weight reduction due to dietary restriction resulted in a proportionately similar 20% decrease in cardiac weight. In contrast, in women after a 27% loss of body weight, cardiac weight decreased only 5%. Severe dietary restriction with a drastic body weight loss did not result in a disproportionate decrease of cardiac weight in either sex, when final body weight had remained above or in the normal range.