Fetal Echocardiography

Dr. Durr-e-Sabih

Una contribucion para Dr Lattus deDr. Hector Fernandez

Why

•Commoner than most realize

• 1% in all live births

• Approximately 5% in all pregnancies

•The incidence increases if there is a positive family history

•if sibling affected incidence is 2 – 4%

•if mother affected incidence is 10-12%

Indications

•Family history

•Exposure to known cardiac teratogens

•Chromosomal abnormalities (trisomy 21, 50%; trisomy 13 and 18, almost 100%)

•Maternal disease (diabetes, collagen disease, phenylketonuria, infections)

•Non-cardiac abnormalities detected on US

•Polyhydramnios

Weeks Length mm

Event`

1-2 1.5 No heart or great vessel

4 2 Single median cardiac tube, ineffective contraction

5 4 Bilobed atrium

5 4 Begining of circulation

5 7.5 AV orifices, 3 chamber heart

6 8.5-13 Septum secundum, complete inferior septum, divided truncus arteriosus,

7 20 4 chamber heart

Cardiac embryology

Cardiac Size

20 week fetus’heart comparedwith an American quarterUsual HR120-160/min

Time

•The best time to do a fetal cardiac exam is 18-22 weeks

•Later exams may show anatomy better but might be difficult because of rib shadowing

•Adequate exam depends on fetal position and maternal habitus

•Some pathologies become obvious with fetal age

Fetal Circulation

Fetal circulation is

complex and different

from adult blood flows

with three major shunts:

Ductus venosus

Forman ovale

Ductus arterosus

Rate and rhythm

•The heart rate is usually 120-160/min,

the rhythm is regular but transient

bradycardia is normal in the 2nd

trimester but not in the 3rd

First assess fetal position

Acquire a four chamber view

•Transverse section through the fetal thorax

•Corresponds to the 4 chamber apical view in the adult

•The atrium nearest the spine is the left atrium

•The atrium nearest the fetal anterior thoracic wall is the right

Axis

•45+20o towards the left

•Abnormal axis increases the risk of a cardiac malformation

•The heart may also be displaced from its normal position in dipaphragmatic hernia or cystic adenomatoid malformation

•Fetus cephalic

•Probe marker to mother’s left

•Fetal spine posterior

•Fetus breech

•Probe marker normal

•Fetal spine posterior

Basic fetal cardiac examination

•Done on a 4 chamber view

•Heart mostly in left chest

•Occupies 1/3rd of thoracic area

•Normal cardiac situs, axis and

position

•No pericardial effusion

General

Basic fetal cardiac examination

•Both of same size

•Foramen ovale flap in

left atrium

•lower end of atrial septum

(septum primum) present

Atria

Atria

•Lower end of septum

•Foramen ovale

•Flap of foramen ovale

in LA

Basic fetal cardiac examination

•Equal size

•Intact septum

•Moderator band

identifies right ventricle

Ventricles

Ventricles

•Both of same size

•Moderator band identifies rightventricle

Basic fetal cardiac examination

•Both valves move freely

•Tricuspid valve inserted

more apically than mitral

AV Valves

Extended basic cardiac examination

•The outflow tracts are imaged by tiltingthe probe towards the fetal head

•The great vessels should be of equal size and should cross at approximately 90o as they emerge from their respective ventricles

Look for these:

•The outflow tracts cross each other at about 90o

•The anterior aortic root wall is continuous with the

Inter Ventricular Septum

•The pulmonary artery bifurcates

•The aortic and pulmonary valves move freely

•Both great vessels are of similar size but the

pulmonary artery tends to be slightly bigger

The aortic arch

•The aortic arch canbe identified

•The aortic cusps can be seen

The pulmonary artery bifurcates

The outflow tracts cross at around 90o

Pulm trunk Aortic arch

Cases

Echogenic Intracardiac Focus (EIF)

•Can be seen in up to 6%of normal pregnancies

•Highly operator and machine dependant

•Associated with cardiacand extracardiac anomalies

•Bilateral EIF is moresignificant

EIF

Biventricular EIF are more significant

this patient was 47XY

Normal nuchal translucency