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
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
Legend: IVIG-intravenous gammaglobulins, LHO-left heart obstruction
Table 1: Lesions which cause fetal cardiovascular compromise and/or evolve to more severe disease and reported prenatal interventions in the mid and third trimesters.