Congenital heart defects (CHDs) represent the most common congenital malformations, especially those affecting the left side of the fetal heart. During fetal life, the presence of the ductus arteriosus is responsible for the low intrauterine mortality rate if compared with the postnatal life. Prenatal diagnosis of CHDs has improved over the past 20 years and diagnostic enhancement has been obtained with the introduction of standardized examination of the fetal heart together with the technological advancement of the ultrasound equipment, particularly with the introduction of the four-dimensional (4D) ultrasound technique based on spatiotemporal- image correlation (STIC) or the application of the three-vessels and trachea view (3VT). The chapter describes and reports the evolution of the antenatal detection of left cardiac malformations, with emphasis regarding the echocardiographic characteristics that need to be evaluated in order to assess the hemodynamic state of the fetus. An extending search and analysis of the medical literature has been sought and describe in relation to the prenatal ultrasound diagnosis of aortic coarctation (CoA), aortic stenosis (AS), interrupted aortic arch (IAA), hypoplastic left heart syndrome (HLHS), aortic arch abnormalities and aorto-pulmonary window (APW). Understanding the cardiac performance of the fertus is of vital and critical importance to plan appropriate management and prognosis. Cardiac defect as critical aortic stenosis (CAS), IAA and HLHS are described as a potential emerging pathogenetic continuum. Attention has been paid to the latest improvement of in utero surgery and technique such as fetal aortic valvuloplasty in case of CAS or severe CoA and the use of multiple scoring system to predict postnatal biventricular circulation are described in great details. Notewithstanding, the chapter is enriched by a series of 2D- as well as 3D/4D ultrasound imaging and videos for each type of left cardiac malformation.
Keywords: 3 Vessel and Trachea view, Aortic arch abnormalities, Aortic coarctation, Aortic stenosis, Congenital heart defects, Doppler ultrasound, Echocardiography, Fetal surgery, Hypoplastic left heart syndrome, Interrupted aortic arch, Prenatal diagnosis, Spatio-temporal image correlation.