Fetal myocardial protection is markedly improved by reduced cardioplegic XXXX content.

@entity64 @entity742 @entity14645 @entity460 @entity1167
BACKGROUND: Fetal cardiac surgery holds a clear therapeutic benefit in the treatment of lesions that increase in complexity due to pathologic blood flow patterns during development. Fetal and neonatal myocardial physiology differ substantially, particularly in the regulation of myocardial @entity460 concentration. To examine issues of @entity460 homeostasis and fetal myocardial protection, a novel isolated biventricular working fetal heart preparation was developed. METHODS: Hearts from 20 fetal @entity742 , 115 to 125 days gestation, were harvested and perfused with standard Krebs-Henseleit (K-H) solution. The descending aorta was ligated distal to the ductal insertion and the branch pulmonary arteries were ligated to mimic fetal cardiovascular physiology. Hearts were arrested for 30 minutes with normocalcemic (n = 8), @entity14645 (n = 6), or hypercalcemic (n = 6) cold crystalloid cardioplegia before reperfusion with K-H solution. RESULTS: Compared with normocalcemic cardioplegia, @entity14645 improved preservation of left ventricular (LV) systolic function (88% +/- 2.2% vs 64% +/- 15% recovery of end-systolic elastance, p = 0.02), diastolic function (12% +/- 21% vs 38% +/- 11% increase in end-diastolic stiffness, p = 0.04), and myocardial contractility (97% +/- 9.6% vs 75.2% +/- 13% recovery of preload recruitable @entity64 work [PRSW], p = 0.04). In contrast, the fetal myocardium was sensitive to @entity1167 with poor preservation of LV systolic function (37.5% +/- 8.4% recovery of elastance), diastolic function (86% +/- 21% increased stiffness), and overall contractility (32% +/- 13% recovery of PRSW). Myocardial water content was reduced in @entity1167 with @entity14645 (79% +/- 1.8% vs 83.7% +/- 0.9%, p = 0.0006). CONCLUSIONS: This study demonstrates the sensitivity of the fetal myocardium to cardioplegic @entity460 concentration. @entity14645 provides superior preservation of systolic, diastolic, and contractile function of the fetal myocardium.
