Fetal Echocardiography

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Fetal Echocardiography

• Dr. Durr-e-Sabih
• Multan, Pakistandsabih_at_yahoo.comhttp//www.geoci
  ties.com/dsabih

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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

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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

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Cardiac embryology
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
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Cardiac Size
20 week fetusheart comparedwith an American
quarter Usual HR120-160/min
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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

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Fetal Circulation
Fetal circulation iscomplex and differentfrom
adult blood flowswith three major shunts Ductus
venosusForman ovaleDuctus arterosus
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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

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First assess fetal position
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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

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Axis

• 4520o 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

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• Fetus cephalic
• Probe marker to mothers left
• Fetal spine posterior

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• Fetus breech
• Probe marker normal
• Fetal spine posterior

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Basic fetal cardiac examination
General

• 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

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Basic fetal cardiac examination
Atria

• Both of same size
• Foramen ovale flap in left atrium
• lower end of atrial septum (septum primum)
  present

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Atria

• Lower end of septum
• Foramen ovale
• Flap of foramen ovale in LA

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Basic fetal cardiac examination
Ventricles

• Equal size
• Intact septum
• Moderator band
• identifies right ventricle

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Ventricles

• Both of same size
• Moderator band identifies rightventricle

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Basic fetal cardiac examination
AV Valves

• Both valves move freely
• Tricuspid valve inserted more apically than
  mitral

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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

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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

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The aortic arch

• The aortic arch canbe identified
• The aortic cusps can be seen

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The pulmonary artery bifurcates
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The outflow tracts cross at around 90o
Pulm trunk
Aortic arch
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Cases
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Echogenic Intracardiac Focus (EIF)

• Can be seen in up to 6of normal pregnancies
• Highly operator and machine dependant
• Associated with cardiacand extracardiac
  anomalies
• Bilateral EIF is moresignificant

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EIF
Biventricular EIF are more significantthis
patient was 47XY Normal nuchal translucency