RADIONUCLIDE IMAGING USING I 125 MIBG IN NEWBORN HEARTS

心肌交感神经的发育性变化 出生后时期产生区域交感神经支配的改变， 暂时导致部分无神经支配。交感神经增多 在部分非神经支配的心室上可能不均匀地传递张力， 这可能会导致危及生命的心室 心律不齐 我们建议绘制心肌交感神经分布图， 新生动物的神经末梢，用I-125间碘苄胍 用~（99）Tc ~（99）m测定心肌灌注分布 Sestamibi，使用定量放射自显影和参数图像。 我们 将使X线摄影结果与 交感神经和肌细胞缝隙连接;沿着高密度 心肌复极的电生理图。 我们还将 检查复极化的空间分散的变化如何提供 在不均匀神经支配的情况下心律失常的底物， 增加交感神经张力，使用计算机建模。这些研究可能 提高对与不明原因突发性心脏病有关的机制的认识， 婴儿死亡综合征（SIDS），婴儿死亡的主要原因， 一岁以上的婴儿，并且可以允许对婴儿进行无创检测， 风险

Developmental changes in myocardial sympathetic nerves during the postnatal period produce alterations in regional sympathetic innervation, transiently leading to partial noninnervation. Increases in sympathetic tone may be delivered unevenly over the partially noninnervated ventricle, which may lead to an increased risk of life threatening ventricular arrhythmia. We propose to map the distribution of myocardial sympathetic nerve endings in newborn animals, with I-125 metaiodobenzylguanidine (MIBG), and the distribution of myocardial perfusion with Tc-99m sestamibi, using quantitative autoradiography, and parametric images. We will correlate scintigraphic results with morphologic density of sympathetic nerves and myocyte gap junctions; along with high density electrophysiologic maps of myocardial repolarization. We will also examine how changes in spatial dispersion of repolarization provides the substrate for arrhythmias in the setting of heterogeneous innervation and increased sympathetic tone, using computer modelling. These studies may improve the understanding of mechanisms relating to unexplained sudden infant death syndrome (SlDS), the leading cause of death in infants less than one year old, and may allow non invasive detection of infants at risk.