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Fetal Cardiac Outflow tract
Aditiawarman
Dept Obstetric and Gynecology
Maternal Fetal Medicine
Airlangga University/ Dr Sutomo General HospitalSurabaya
Abnormalities
• Cardiac abnormalities 0.8% of all
pregnancies.
• Cardiac anomalies are the most frequently
overlooked group of abnormalities
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• The presence of associated abnormalities
increases the detection rate.
• Cardiac defects affecting the size of the
ventricles the highest detection rate.
•Gestational age
•Routine examination of the
four-chamber view•Routine examination Inflow
and outflow tracts of the fetal
heart.
Prenatal
detection of
congenital heartdefects increases
with
• The etiology of heart defects is heterogenous Interplay of multiple genetic and environmental factors
• Environmental: – maternal diabetes mellitus – collagen disease – exposure to drugs : lithium – viral infections : rubella.
• Genetic – 4% one sibling
– 10% two siblings
– 9% father affected
– 12% mother affected
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Risk factors
• Risk Factors for congenital heart disease:
• Family history
– Recurrence risk (hypoplastic left heart as high as13.5%)
– Nongestational DM
– Maternal infection (rubella)
– Lupus
– Drugs (anticonvulsants, etoh, amphetamines, ocp,vit A, steroids, etc.)
Anatomy and Approach
• The connections Veno-Atrial junction
Atrio-Ventriculo Ventriculo-Arterial
Ductal and Aortic arches
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Identification
• Atria
• Ventricles
• Valves: atrio-ventricular
• Septa: ventricular and atrial
• Flap: foramen ovale
Identification
• Cardiac chamber:
– Cardiac chambers reference to the
spine.
– Opposite the spine anterior chest wall
and beneath this is the right ventricle.
• Atria approximately equal size.
• Ventricles approximately equal size and
thickness.
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• Ventricle:
– Apex of the right ventricle moderator
band.
– Left ventricle smooth inner wall.
• Descending aorta :
– Circular structure
– Lying anterior to the spine,
– Anterior to this is the left atrium.
• Pulmonary veins into the left atrium
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• The atrial and ventricular septa meet the
two atrioventricular valves at the crux of
the heart.
• The foramen ovale flap in the left
atrium, beating toward the left side.
• The insertion of the tricuspid valve more
apical than the insertion of the mitral
valve.
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4 Chamber view
• Improved equipment
• Detailed descriptions
view
About 90% of ultrasonographically detectable
fetal cardiac defects demonstrate someabnormalities in this view
Allow a high degree
of diagnostic
accuracy in the
detection of fetal
cardiac defects
Axial views:
• 4-chamber view
• 3-vessel view
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Oblique views:
• Long axis of the left ventricle
• Long axis of the right ventricle
• Short axis of the right ventricle
Sagittal views:
• Cavo-atrial junction
• Aortic arch
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LVOT and RVOT
• Views of LVOT and RVOT integral part
of the fetal cardiac screening
examination.
– Ascertain normality
– Connection to the appropriate ventricles
– Relative size
– Position
– Adequate opening of the arterial valves.
• SIZE The great vessels are approximately
equal in size
• CROSS OVER The great vessels are cross
each other at right angles from their origins as
they exit from the respective ventricles(normal ‘cross-over’)
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How to obtain
• Left out flow tract
–Four-chamber view
–Rotate the transducer slowly in an arc
that would eventually encompass a
plane moving through a line drawn
between the left hip and the rightshoulder.
• Right Out flow tract
–Four-chamber view
–Tilt the transducer toward the chin of
the fetus
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• Even with persistence, in about 10 –20% of
cases one still cannot get both outflow tracts
with this technique.
• If one is not doing a full fetal
echocardiogram the crossing of
the great vessels can be appreciated
by ashort axis view
– the pulmonary artery is caught swinging
around the aorta
– the “sausage and circle” view
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• Above the four-chamber view
–Three-vessel view
–Obtained by moving the transducer
transversely further cephalad –Just above this one “tracheal view”
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• Most (93%) examinations that included an
adequate four-chamber view were also
associated with satisfactory evaluation of the
outflow tracts.
• Non-visualization rates were: 4.2% for the
LVOT, 1.6% for the RVOT and 1.3% for both
outflow tracts.
• Additional cross-sectional views show
different aspects of the great vessels and
surrounding structures, but are part of a
continuous sweep starting from the RVOT and
include the three-vessel (3V) view and thethree vessels and trachea (3VT) view
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LVOT
• The LVOT view a great vessel originating
from left ventricle
• Continuity between the ventricular septum
and the anterior wall of the aorta.
• The aortic valve moves freely and should notbe thickened.
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• It is possible to trace the aorta into its arch,
from which three arteries originate into the
neck:
– A Carotic
– A Brachiocephalica
RVOT
• Identify branching of the main PA into
– Right PA
– Ductus arteriosus (desc Aorta)
• Asc aorta in cross section with PA anteriorly
• Desc aorta to left of spine;
• Pathology: transposition, truncus arteriosus
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RVOT
• The RVOTa great vessel originating from
ight ventricle.
• PA arises from Right ventricle towards the
left , more posterior ascending aorta.
• Usually slightly larger than the aortic root
during fetal life
• Crosses the ascending aorta at almost a rightangle just above its origin
• Superior vena cava is often seen to the right of
the aorta.
• This view is similar to the 3V view.
• Pulmonary valve moves freely and should not
be thickened.
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• Medial wall of the ascending aorta merges
with the top of the IV septum (most frequent
location for VSD)
• Pathology: VSD, tetralogy of Fallot,
transposition,truncus arteriosus
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• Cardiac abnormalities 0.8% of all
pregnancies.
• Cardiac anomalies are the most frequently
overlooked group of abnormalities
• The connections Veno-Atrial junction
Atrio-Ventriculo
Ventriculo-Arterial
Ductal and Aortic arches
Resume
• Views of LVOT and RVOT integral partof the fetal cardiac screeningexamination.
– Ascertain normality
–Connection to the appropriate ventricles
– Relative size
– Position
– Adequate opening of the arterial valves.
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