MYOCARDIAL EFFECTS OF EXPERIMENTAL NEOPLASTIC DISEASE

The purpose of this study was to determine the effects of the 7288ctc Morris hepatoma on heart size and performance. Hearts from tumor beari ng and control animals were perfused in the working configuration one to three weeks post implantation. As tumor growth progressed there was an inverse linear relationship between tumor size and heart weight. W hen intrinsic heart work (defined as the product of the cardiac output and peak systolic pressure) was assessed in vitro over a range of phy siologic preloads, significant differences were found between tumor-be aring and non-tumor-bearing animals. The hearts from the tumor-bearing animals (tumor weight 10-20 grams) developed only 76% of the heart wo rk of control animals at maximal left atrial filling pressure (25 cm H 2O). Hearts excised from rats with tumor masses from 30-65 grams devel oped 43% of the myocardial work as controls at the same (25 cm) preloa d. At the time of sacrifice resting blood pressures, blood glucose, in sulin, and tumor necrosis factor (TNF) levels were similar in both gro ups. Blood from tumor bearing animals were negative for both aerobic a nd anaerobic bacteria. The data suggests that the decrements in cardia c size and performance are independent of several vectors known to inf luence heart size and performance and occur in the absence of detectab le bacteriemia.