Effect of chronic caffeine intake on myocardial function during early growth.

The purpose of these studies was to evaluate the effects of chronic caffeine ingestion on the myocardium during fetal and neonatal growth and development. The isolated perfused working heart preparation was used to evaluate cardiac function. During gestation and lactation, one group of dams consumed a caffeine supplemented diet (10 mg/kg/day). Their offspring were sacrificed and the hearts analyzed 50 days after birth. We found that the intake of caffeine by the dams resulted in significant increases in the offspring's coronary flow, peak systolic pressure, and myocardial work. A second group of dams ingested a diet containing caffeine (10 mg/kg/day) during lactation only. Their pups continued to consume the caffeine diet until 50 days. Pup hearts exhibited significant reductions in cardiac output, stroke volume, pressure development, myocardial work, and external efficiency when compared to controls. Caffeine did not affect body or heart weight or adipose size or number in these experiments. Thus, continued caffeine consumption following birth may alter cardiac performance of the offspring.