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Myocardial Mass in Morbidly Obese Patients and Changes with Weight Reduction
1Medical and Research Services, V.A. Medical Center, West Los Angeles, Wadsworth Division, Los Angeles, CA 90073; the University of California, School of Medicine, Los Angeles, CA 90024 USA.
Insights
Cardiac weight in morbidly obese individuals is lower than predicted. Significant weight loss through diet restriction proportionally decreased cardiac weight in men but not in women.
Area of Science:
- Cardiology
- Obesity Medicine
- Autopsy Studies
Background:
- Morbid obesity is associated with significant health risks, but cardiac adaptations in this population require further investigation.
- Previous studies suggest a potential increase in cardiac mass with obesity, yet data on cardiac weight relative to body weight in morbidly obese individuals is limited.
- Understanding cardiac weight changes in relation to body mass and weight loss is crucial for assessing cardiovascular health in obesity management.
Purpose of the Study:
- To determine cardiac weight in morbidly obese individuals who died suddenly before or after bariatric surgery.
- To compare cardiac weight in morbidly obese individuals with and without significant weight loss post-surgery.
- To analyze the relationship between body weight reduction and changes in cardiac weight in both men and women.
Main Methods:
- Cardiac weight was measured post-mortem in two groups: morbidly obese individuals who died before or shortly after gastric restriction surgery (no weight loss) and those who underwent surgery and subsequent hypocaloric dieting, followed by sudden death.
- Body weight, body mass index, and cardiac weight were recorded for all subjects.
- Cardiac weight was calculated as a percentage of body weight and compared to predicted values and to changes observed after significant weight loss.
Main Results:
- Morbidly obese men had 16% lower cardiac weight (0.035% of body weight) and women had 25% lower cardiac weight (0.030% of body weight) than predicted.
- In men who lost a mean of 28% body weight, cardiac weight decreased by a similar 20%.
- In women who lost a mean of 27% body weight, cardiac weight decreased by only 5%.
Conclusions:
- Cardiac weight in morbidly obese individuals is lower than typically predicted based on body weight.
- Significant weight loss achieved through dietary restriction led to a proportional decrease in cardiac weight in men.
- Women exhibited a less pronounced reduction in cardiac weight despite substantial weight loss, suggesting potential sex-based differences in cardiac adaptation to weight reduction.
Abstract:
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.