Hematocrit, during bypass, 1399 Hemi-Fontan procedure, 1296–1297, 1297f Hemochromatosis, cardiac involvement in, 1108–1109 Hemoconcentrators, in cardiopulmonary bypass, 227 Hemodilution, in cardiopulmonary bypass, 228 Hemodynamic assessment, in prematurity, 192–195 blood pressure, in circulatory stability, 192, 193f hypotension, brain injury and, 192–194, 194f preterm circulation, monitoring, 194–195, 195f Hemodynamic instability, in complex congenital cardiac disease, 1399–1400 Hemodynamic variables, in diagnostic catheterization, 240–242, 241b calculations in, 241–242 Hemodynamics in Ebstein malformation, 596 echocardiographic measurements and, 305–306 mean pressure gradient, 306, 306f during pregnancy, 1441 in tetralogy of Fallot, 642–643 Heparin for cardiac catheterization, 255 in cardiopulmonary bypass, 1289 in Kawasaki syndrome, 994–995 Hepatic hemangioma, 927–928 Hepatic veins, in diagnostic catheterization, 244 Hereditary motor and sensory neuropathy, cardiac involvement in, 1106 Hers disease, cardiac involvement in, 1089 Heterotaxy, 1419–1420 visceral, 441 High dependency, for integrated care pathways, 1482t High-fidelity continuous physiologic data, in Fontan pathway, 1275, 1288–1289 High-resolution episcopic microscopy (HREM), 88 High-risk clinic/follow-up, in interstage management, 1313–1314 Histamine, in control of circulation, 1358 HLA sensitization, cardiac transplantation and, 1226–1227 HLHS, Hypoplastic left heart syndrome HMG-CoA, 3-Hydroxy-3-methyl-glutaryl coenzyme A Holt-Oram syndrome, 52–53, 503, 509, 1416–1417, 1416f, 1416t Home monitoring, in interstage management, 1311–1312, 1313f–1314f Homocystinuria cardiac involvement in, 1102 homozygous, systemic arterial dysfunction and, 1371 Homograft, 220 Homograft valves, 222–223, 222f Homozygous homocystinuria, systemic arterial dysfunction and, 1371 Hospitalization, psychological stress of, 1455 Howell-Jolly bodies in isomeric atrial appendages, 454 HREM, High-resolution episcopic microscopy Human immunodeficiency virus, in viral myocarditis, 1173 Human leukocyte antigen alleles, associated with rheumatic fever, 1001, 1001t Human myocardial development, 61, 62f Humoral control, of circulation, 1357–1358 Hunter syndrome, cardiac involvement in, 1090–1091 Hurler syndrome, cardiac involvement in, 1089–1090 Hurler-Scheie syndrome, cardiac involvement in, 1090 Hutchinson-Gilford progeria, cardiac involvement in, 1112 HVAD, in long-term mechanical circulatory support, 1209–1210 Hybrid catheter/cardiac magnetic resonance laboratory, 328–329, 329f Hybrid palliation, 1281 Hybrid procedure, 1281, 1282f, 1284 in interventional techniques, 276–279, 276f combined procedures and, 278–279, 278f–279f for hypoplastic left heart syndrome, 276–277, 277f novel treatments in, 276–278 pulmonary valve replacement and, 278 for ventricular septal closure, 277–278, 277f–278f Hydralazine for hypertension, 1140t–1141t for systemic hypertension, in premature infants, 208f 3-Hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA), 1436 11β−Hydroxylase deficiency, hypertension in, 1136 17α−Hydroxylase deficiency, hypertension in, 1136 Hypercalcemia, hypertension in, 1138 Hypercholesterolemia, familial, systemic arterial dysfunction and, 1371 Hypermetabolism, growth and, 1495–1496 Hyper-reninism, primary, renal hypertension and, 1135 Hypersensitivity myocarditis, drugs producing, 1111, 1111b Hypertension cardiovascular risk factors, 426–428, 427f–428f, 427t–428t following cardiac transplantation, 1238–1239 Hypertensive crisis, medical therapy for, 1141–1142, 1141t Hyperthyroidism, cardiac involvement in, 1096 Hypertriglyceridemia, pharmacologic therapy for, 433, 434f Hypertrophic cardiomyopathy, 77, 1145–1155, 1146b cardiopulmonary exercise testing in, 1153 clinical features of, 1150–1153 clinical outcomes of, 1145–1147 definition of, 1145 in diagnostic catheterization, 250