selection of, 223–225, 224f xenobioprosthetic, 222, 222f Valve-sparing aortic root replacement, 1084 Valvitis, subclinical, in rheumatic fever, 1008–1009, 1008b Valvular severity grading, 1030–1031 Vancomycin for blood culture-negative endocarditis, 1054t for infective endocarditis, 1053t Variables, 409 types of, 410–411 Vascular access in diagnostic catheterization, 239 in interventional techniques, 254–255 Vascular anomalies, 1414 Vascular catheters, indwelling, in Fontan pathway, 1274–1275, 1288 Vascular impedance, 1361, 1361f Vascular malformations, in diagnostic catheterization, 251 Vascular occlusion, closure of, in interventional techniques, 257 Vascular physiology, fetal, assessment of, 101–102, 101f Vascular programming, 104–106 following fetal coarctation, 106, 106f in setting of restricted growth, 104–106 in twin-twin transfusion syndrome, 106 Vascular resistance, ventricular afterload and, 1360–1361 Vascular rings, 877–900 partial, 877 Vascular smooth muscle, function of, 1356–1357 Vascular smooth muscle cells, in myocardial development, 64–65, 65f Vascular tone, endothelial function and, 1356 Vascular tumors, cardiac, 974, 974f Vasculitides, childhood, systemic arterial dysfunction and, 1372–1373 Vasculogenesis, 65–66 Vasculopathies, in syndromal disorders, 1373 Vasculopathy of cardiac allograft, 1232–1233, 1232f risk factors and diagnosis of, 1225t, 1232, 1233f–1234f treatment of, 1233 Vasoactive medications, for acute circulatory failure, 1184t Vasodilators for hypertension, 1140–1141, 1140t Vasomotor regulation, in prematurity, 201 Vasopressin for acute circulatory failure, 1184t in control of circulation, 1358 for hypotension and circulatory collapse, in prematurity, 202–204 for pulmonary hypertension, 206–207 Vasopressor agents, for hypotension and circulatory collapse, in prematurity, 202–204 Vein of Galen, aneurysm of, 929–931 clinical manifestations of, 929 diagnosis of, 929–930, 929f–930f management of, 930–931, 930f–931f Velocity-encoded phase-contrast images, 322–323 Venoatrial connections, anomalous, with isomeric atrial appendage, 442–443 Venous components, embryology of, 36–37, 36f–38f Venous duct absence of, 471 fetal circulation and, 86–87, 86f flow in, fetal, 92, 92f persistence of, 471 pulse-wave Doppler of, 131, 131f Venous flow, 320t–321t Venous obstructions, interventional techniques for, 269–275 Venous sinus, embryology of, 36–37 Venovenous collaterals, 1269–1270, 1270f–1271f in Fontan circulation, 1341, 1342f Ventilation for acute circulatory failure, 1182–1183, 1184t with abnormalities of diastolic function, 1183 with functionally univentricular circulation, 1183 in healthy circulation, 1182, 1182f with systolic ventricular dysfunction, 1182–1183 in extremely premature neonate, 191 for hemodynamically significant arterial duct, 198 minute, 384–385 voluntary, maximal, 385 Ventilation-perfusion scintigraphy, in pulmonary hypertension, 1388 Ventilatory anaerobic threshold, 380–381 evaluation of, exercise testing for, 392 Ventricles diastolic properties of, pressure-volume relationship for, 1196 left, anatomy of, 24–25, 24f–26f morphology of, 4–5, 7f origin of arterial trunks from, 13–14 relationships of, 13 right, anatomy of, 22–24, 22f–24f solitary, 6, 7f superoinferior, 920–926 topology of, 5–6, 7f, 13 in univentricular hearts complex double-outlet, 1257–1258 double-inlet, 1253–1254, 1253f–1254f Ventricular afterload, arterial impedance as, 1360–1361 Ventricular arrhythmias, 350–351