Alterations in cardiac composition with weight reduction in the obese rat

Alterations in myocardial composition associated with obesity and weight reduction have been examined in the spontaneously obese rat. When compared to values obtained from obese animals, body weight reduction was associated with a significant decrease in body fat, heart weight, and absolute left ventricular mass. Compositional analysis indicated that protein, lipid, and water together accounted for approximately 98% of total heart weight, and that while each component decreased with weight reduction, decreased myocardial water content represented the largest contribution to the reduced total heart weight. These data therefore suggest that the cardiomegaly of obesity is contributed to by specific changes in myocardial composition which can be altered through body weight reduction.