Diagnostic ultrasound ( PDFDrive )

CHAPTER 37 The Fetal Heart 1285
Normal tricuspid and mitral valves
Partial atrioventricular septal defect
Anterosuperior
leaflet
Aortic leaflet
A
Inferior leaflet
Septal leaflet
Tricuspid
valve
Mitral
valve
Mural leaflet
B
“Cleft”
RT
LT
Complete atrioventricular septal defect
Anterosuperior
leaflet
Anterior
bridging leaflet
C
Right mural
leaflet
RT
LT
Left mural
leaflet
Posterior
bridging leaflet
FIG. 37.26 Valve Lealet Morphology. (A) Normal heart. (B) Partial atrioventricular septal defect (AVSD). (C) Complete AVSD. LT, Left abnormal
valve; RT, right abnormal valve.
RA
LA
RA
LA
RV
LV
RV
LV
A
B
FIG. 37.27 Atrioventricular Septal Defect (AVSD). (A) Apical four-chamber view shows absent atrial septum, resulting in a single large atrium
(RA-LA). A ventricular septal defect is visible between the left ventricle (LV) and right ventricle (RV). A single, multilealet atrioventricular valve is
also appreciated. (B) Apical four-chamber view shows color Doppler ultrasound illing the atrioventricular septal defect. See also Video 37.9. LA,
Left atrium; RA, right atrium.
oriices. Complete AVSD has variable amounts of deicient tissue
in the atrial and ventricular septa. he incomplete form is associated
with an ostium primum ASD. At fetal echocardiography,
97% of AVSDs are complete, although ater birth only 69% are
complete. 67,72 he fetal incidence of AVSD is four times greater
than that in the live-born population, indicating a high incidence
of in utero demise. 46,47,77
AVSDs are considered balanced when the A-V junction is
connected to both the right and the let ventricle, such that blood
low is relatively evenly distributed. If this connection exists with
primarily one ventricle, such as in the setting of a hypoplastic
let ventricle, it is termed an unbalanced AVSD.
Sonographically, a defect in the atrial or ventricular septum
with an associated single abnormal A-V valve is visible in a
four-chamber view (Fig. 37.27, Video 37.9). he abnormal valve
should be suspected when the normal ofset of the A-V valves
is not visualized or when only a single A-V valve is appreciated
in a short-axis view. Demonstration of two A-V valve oriices
allows for diferentiation between complete and incomplete forms
of AVSD. 62
Color Doppler ultrasound demonstrates an open area of low
across the AVSD and the abnormal A-V valve. Color Doppler
ultrasound imaging is particularly useful in the detection of
valvular insuiciency. 78 Holosystolic valvular insuiciency is