ABC | Volume 112, Nº5, May 2019

Guideline Brazilian Fetal Cardiology Guidelines – 2019 Arq Bras Cardiol. 2019; 112(5):600-648 Table 4.1 – Classification of fetal anomalies according to fetal outcome Group Fetal outcome I Heart diseases without fetal hemodynamic compromise A. Structural B. Functional II Heart diseases with fetal hemodynamic compromise A. Structural B. Functional III Heart diseases with poor postnatal prognosis 4.1.2. Functional This group includes cardiac rhythm abnormalities such as isolated supraventricular extra beats and mild isolated tricuspid regurgitation. 4.2. Group II − Heart Diseases with Fetal Hemodynamic Compromises 4.2.1. Structural This group includes cardiac defects that may compromise the development of cardiac structures throughout gestation, such as critical or total obstruction of the ventricular outflows, 42,43 defects that potentially trigger heart failure due to the presence of severe valvular insufficiency, 44 and anomalies that require patent foramen ovale to divert flow from one chamber to the other (atrioventricular valves atresia or stenosis), being the main examples HLHS and tricuspid atresia. 45 This group requires special attention, and some of the cases may benefit from a fetal cardiac intervention to increase the blood mixture at the atrial level (see the Fetal Interventions Chapter). 44 4.2.2. Functional Primary fetal myocardial dysfunctions have various etiologies. They may be caused by myocarditis (usually viral), structural changes in myocardial fibers (noncompacted myocardium, deposit diseases such as mucopolysaccharidoses or glycogenoses), and they may be related to maternal diabetes and genetic conditions. 46,47 Severe cardiac arrhythmias, such as sustained tachyarrhythmias and complete atrioventricular block (CAVB) lead to cardiac chambers dilation, atrioventricular valves regurgitation, and myocardial dysfunction. 48 Tachyarrhythmias are considered emergencies in Fetal Cardiology due to the risk of hydrops and fetal death; being the majority of cases possible to be treated with antiarrhythmic medication. 49 Cardiac tumors are rare. The most prevalent in fetal life is rhabdomyoma. They may be single or multiple and their dimensions increase during fetal life. 50 Serial echocardiograms are indicated because of the risk of arrhythmias, ventricular outflow obstructions, or cardiac structures compression. Functional abnormalities of the intracardiac shunts may imbalance the distribution of fetal blood flow. Ductal arteriosus constriction, the most frequent, will be detailed discussed in a subsequent chapter. 51 Restrictions of blood flow through the foramen ovale and agenesis of the ductus venosus are rare conditions. Both evolve with right chamber dilation and may lead to fetal heart failure. 52,53 High-output fistulas may lead to cardiac chambers dilation and dysfunction and fetal hydrops. The most frequent are Galen’s vein aneurysm, hemangioma, hepatoblastoma, pulmonary arteriovenous malformation, vascularized tumors such as sacrococcygeal or cervical teratoma, and the twin- twin transfusion syndrome. 54,55 Severe anemia resulting from viral infection or blood type incompatibilities may lead to heart failure. Fetal hemodynamics may also be compromised by extrinsic fetal heart compressions, such as diaphragmatic hernia, pulmonary cystic adenomatoid malformation, and pericardial tumors. This group needs serial fetal echocardiograms, ideally biweekly, and this interval may be reduced if needed. The cardiovascular profile score, published by Huhta et al should be employed to establish the outcome. 56 4.3. Group III − Fetal Heart Diseases with Limited Postnatal Prognosis This group corresponds to very severe heart diseases in which, any therapeutic measurements will result in nearly 100% chance of death. It includes severe forms of left atrial isomerism associated with CAVB, obstruction of both ventricular outflows tracts and myocardial disease, critical obstructive malformations associated with noncompacted myocardium, the worst spectra of Ebstein’s anomaly or tricuspid valve dysplasia associated with lung hypoplasia, left ventricular aneurysms with fetal congestive heart failure, and heart diseases associated with chromosomal disorders with limited prognosis (trisomies of 13 and 18). In this group, multidisciplinary follow-up, including psychological support for parents must be prioritized, but delivery may be in a hospital with basic support (Table 4.2). 5. Management of the Main Fetal Heart Diseases One of the main challenges for the ultrasound specialist and pediatric cardiologist is to know exactly 616