CHRONIC ALTERATIONS IN CARDIAC MECHANICS AFTER FETAL CLOSED HEART OPERATION

Pulmonary artery banding was performed in 8 fetal sheep at 125 days' g estation to evaluate the feasibility of fetal closed cardiac operation . At 135 days' gestation, the fetuses were delivered and the cardiac m echanics were evaluated using a modified Langendorff isolated heart pr eparation. Two of the 8 fetuses aborted spontaneously 2 and 7 days aft er operation. Six fetuses (75%) survived the 10 days after delivery. T he left ventricular cardiac mechanics in the banded fetuses (group I) were compared with those in 8 control fetuses (group II). All fetal he arts in both groups displayed a significant volume-pressure relationsh ip. The volume-pressure curve was found to be shifted upward and to th e left in the fetal hearts after pulmonary artery banding. The left ve ntricles subjected to increased in utero preload Secondary to pulmonar y artery banding were capable of generating greater peak systolic and developed pressures. because the fetal heart manifests a Starling type of preload reserve, as such, it demonstrates that the possibility exi sts for subsequent fetal development to be altered by intrauterine int ervention.