| High Output States |
| Fetal anemia |
fetal transfusion |
| Arteriovenous malformations |
laser ablation/coil occlusion/ tumor resection |
| Twin reversed arterial perfusion (acardiac) |
radiofrequency ablation of a cardiac twin, cord occlusion |
| Fetal hyperthyroid state +/- goiter |
increasing antithyroid drugs |
| Cardiac compression |
| Congenital cystic adenomatous malformation |
resection/cyst drainage/ thoraco-amniotic shunting |
| Large pleural effusions |
pleurocentesis/thoraco- amniotic shunting |
| Massive pericardial effusions |
pericardiocentesis/shunt placement |
| Congenital diaphragmatic hernia (liver up) |
balloon tracheal occlusion |
| Congenital high airway obstruction syndrome |
fetoscopic perforation (relief of obstruction) |
| Altered afterload |
| Twin-twin transfusion syndrome recipient |
laser coagulation of placental vascular connections/amnioreduction |
| Primary myocardial disease |
digoxin, IVIG for acute infection |
| Structural heart disease |
| Critical aortic outflow tract obstruction |
aortic valvuloplasty |
| Severe LHO with intact atrial septum |
atrial septoplasty/stenting |
| Critical pulmonary outflow tract obstruction |
pulmonary valvuloplasty |
| Arrhythmias |
| Supraventricular tachycardia |
transplacental/direct antiarrhythmic therapy |
| Atrial flutter |
transplacental/direct antiarrythmic therapy |
| Ventricular tachycardia |
transplacental antiarrhythmic therapy |
| Complete atrioventricular block |
β sympathomimetics, Corticosteroids and IVIG (autoimmune-mediated), plasmapheresis, intrauterine pacing |
