Fetal Cardiac Outflow Tract

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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.

Documents

Fetal Cardiac Outflow Tract