U Ubiquitin proteasome system, 70 Udenafil, for pulmonary hypertension, 1390 UDP-glucuronosyl transferases, 1434–1435 UGT1A1, 1434–1435 UGT1A6, 1434–1435 UGT2B7, 1434–1435 Uhl malformation, 589–590, 603–605, 605f Ultrafiltration, in cardiopulmonary bypass, 232 Ultrasound artifacts affecting images of, 283 of central nervous system, in Fontan pathway, 1291 image production and, 282 image quality and, 283 physical properties of, 281–282 second harmonic imaging, 282–283 spatial resolution and, 283 temporal resolution and, 283 Umbilical arterial catheters, 1499 Umbilical artery, pulse-wave Doppler, 129, 129f Umbilical cord, flow in, fetal, 90–91, 91f Umbilical veins, 457 pulse-wave Doppler of, 130, 131f Unanticipated hypoxemia, 1268–1270, 1268f, 1269t Unbalanced atrioventricular septal defect, in univentricular hearts, 1256–1257 Undernutrition, on congenital heart disease, 1525–1526, 1526f Unfolded protein response, 69 Univentricular circulation, functionally, cardiopulmonary interactions in, 1183 Univentricular heart, 3, 6, 463–464, 1317–1351 Fontan circulation in, Fontan circulation functionally, anatomic considerations in, 1245–1259 atrioventricular valvar atresia in, 1250–1253, 1251f–1252f complex double-outlet ventricle in, 1257–1258 double-inlet ventricle in, 1253–1254, 1253f–1254f hypoplastic left heart syndrome in, 1248–1249, 1248f–1250f morphogenesis of, 1258–1259, 1259f philosophical considerations with, 1245–1246, 1246f–1247f pulmonary atresia with intact ventricular septum in, 1249–1250, 1250f–1251f straddling atrioventricular valves in, 1254–1256, 1255f–1258f unbalanced atrioventricular septal defect in, 1256–1257 functionally, physiologic principles to maximize outcome in, 1261–1270 birth, physiology immediately after, 1261–1264 clinical presentation of, 1261–1262 fetal and transitional circulation, 1262–1264 clarifications and proposed changes to, 1264–1266 parallel circulation in, 1264–1265, 1264f pulmonary and systemic blood flow, balancing, 1264f pulmonary overcirculation in, 1264f single-ventricle physiology in, 1265–1266 medical management of, 1261 staged reconstruction in guiding principles of, 1261, 1262b physiologic effects of, 1264f, 1266t–1267t serial physiologic data during, 1267t, 1268 strategies and physiologic goals of, optimal outcome and, 1261, 1262t, 1263f superior cavopulmonary connection in, 1266–1267, 1266f–1267f surgical management of, 1261 total cavopulmonary connection (Fontan procedure) in, 1268 unanticipated hypoxemia in, 1268–1270, 1268f, 1269t venovenous collaterals in, 1269–1270, 1270f–1271f future directions in, 1348–1351 exercise programs, 1348–1349, 1349f–1350f implanted ventricular assist devices, 1350–1351 lymphatic drainage abnormalities, novel treatments for, 1351 other medical therapies, 1349 practice variation, networks and registries, 1349–1350 selective pulmonary vasodilators, 1348 surgical design and computational fluid dynamics, 1350 late predictors for, 1320, 1320f in pregnancy, 1446 Univentricular junctions, in isomeric atrial appendages, 448 Universal health care models, integrating pediatric health care into, 1531 Unobstructed systemic and pulmonary blood flow, 1280, 1280f UNOS, 1511t–1514t Unrepaired congenital heart disease, pulmonary vascular disease in, 1381–1383, 1383f Urinary catheter, in Fontan pathway, 1289 US National Registry of Sudden Death in Athletes, 1511t–1514t V Vaccines, against rheumatic fever, 1002 VACTERL association, 1417, 1418f, 1418t VAD, Ventricular assist device Vagus nerve, anatomy of, 17, 19f Validity, of data, 409–410 Valproic acid, for carditis, 1017t Valvar heart disease, intracardiac interventions for, 257–263 Valvar pulmonary atresia, with intact ventricular septum, interventional techniques for, 258, 258f Valvar regurgitation, 326–327, 327f Valve areas, in diagnostic catheterization, 242 Valveless conduits, in surgical techniques, 220–221 Valves, in surgical techniques, 221–225 homograft, 222, 222f mechanical, 221–222, 221f pulmonary autograft, 223 repair, 225 ... Univentricular junctions, in isomeric atrial appendages, 448 Universal health care models, integrating pediatric health care into, 1531 Unobstructed systemic and pulmonary blood flow, 1280, 1280f UNOS, 1511t–1514t