Fetal Ventricular Inflow Anomalies
Pp. 1-21 (21)
Nathalie J. Magioli Bravo-Valenzuela
Congenital heart diseases (CHDs) are largely known as an important cause
of fetal perinatal mortality. Currently, the accuracy of fetal echocardiography enables
the detailed diagnosis of a significant variety of congenital cardiac anomalies, and it
has also been demonstrated that prenatal outcomes may improve in critical CHDs.
Accordingly, this chapter provides a detailed overview of the important anatomic
aspects of some of the ventricular inflow anomalies, focusing on currently available
information, to enable the prenatal diagnosis of such CHDs by ultrasound or
echocardiography. Information regarding prenatal management, delivery plan
strategies, and differential diagnosis of such anomalies is presented. The chapter also
discusses the parental counseling and fetal and neonatal therapeutic management of
such congenital cardiac anomalies. Univentricular atrioventricular (AV) connections,
straddling and overriding of AV valves, and crisscross hearts are described in the
current chapter. The concept of “functionally single ventricle” encompasses a group of
CHDs in which the dominant ventricular chamber is responsible for maintaining the
systemic and pulmonary circulations and not suitable for a biventricular repair. The
central feature of such hearts is the univentricular AV connection. Regarding the type
of the straddling of an inlet valve, it is based on the insertion of the tension apparatus of
the AV valve into the crest of the ventricular septum or in the contralateral ventricle.
Meanwhile, overriding of an inlet valve is related to the annulus of the AV valve and
may interfere in the AV connection. Depending on the degree of the overriding of the
straddled valve, the ventricles are in a dominant and rudimentary relationship, and a
double-inlet AV connection, primarily the double-inlet left ventricle is the most
frequent type of AV connection. In general, straddling and overriding of an AV valve
requires a ventricular septal defect, and straddling may occur alone or in the presence
of an overriding. In “crisscross” hearts, the ventricular inlet flows are in a cross shape
and the ventricles are arranged in a superoinferior relationship. During an ultrasound
examination, the crossed AV valves produce false images of the mitral valve or
tricuspid atresia in a standard 4-chamber view, which makes the diagnosis difficult. In
fact, the knowledge about the detailed anatomy, the assessment of the ventricular
outflow tracts, and the identification of other possible associated cardiac anomalies are important for improving In Utero and postnatal management in ventricular inlet
anomalies described in the current chapter.
Cardiac valves, Chordae Tendineae, Congenital heart disease, Crisscross Hearts, Double-inlet ventricle, Echocardiography, Mitral valve, Prenatal diagnosis, Single ventricle, Tricuspid valve, Univentricular heart, Ventricular morphology.
Department of Obstetrics, Discipline of Fetal Medicine, Paulista School of Medicine, Federal University of São Paulo (EPM-UNIFESP), São Paulo-SP, Brazil.