Fetal Heart Orientation and Views

What percentage of cardiac anomalies can be detected with the 4-chamber view

50-60%

What percentage of cardiac anomalies can be detected when including great vessel imaging

Up to 85%

At what gestational age is the 4-chamber view obtainable in most cases

Around 18 weeks (~95%)

What is fetal lie

The orientation of the fetus in the uterus (longitudinal, transverse, oblique)

What is fetal presentation

The part of the fetus closest to the cervix

What are the types of fetal lie

Longitudinal, transverse, oblique

What are the types of fetal presentation

Vertex (head), breech (butt/feet), transverse

What landmark should the spine be assigned to

6 o'clock

What landmark represents the front of the fetus

12 o'clock

In vertex or transverse head right, how do the stomach and heart orient

Clockwise toward 9 o'clock

In breech or transverse head left, how do the stomach and heart orient

Counterclockwise toward 3 o'clock

What is levoposition

Heart located in the left chest (normal)

What is mesoposition

Heart located in the midline of the chest

What is dextroposition

Heart located in the right chest

What is the most common cause of dextroposition

Extrinsic mass effect (e.g., CPAM, pleural effusion, diaphragmatic hernia)

What is cardiac axis

The angle/orientation of the cardiac apex within the chest

What is the normal cardiac axis

45° ± 20° toward the left

What percentage of the chest should the heart occupy

About 1/3

What is levocardia

Apex points to the left (normal)

What is mesocardia

Apex points midline

What is dextrocardia

Apex points to the right

What 4 chamber views are these from left to right?

Apical

Subcostal

Basal

What are the three angles used to obtain the 4-chamber view

Apical, subcostal, basal

Which view is best for detecting septal defects (VSD, ASD)

Subcostal view

Why is the subcostal view best for septal defects

The ultrasound beam is perpendicular to the septum

How much of the chest should the heart occupy

1/3

What should be seen on either side of the chest in a proper view

Ribs

What should the cardiac axis be

~45° to the left

What should be true about the interventricular septum

It should be intact

How should the atria and ventricles appear

Symmetric

Which valve is more apical, tricuspid or mitral

Tricuspid

Where should the inferior pulmonary veins enter

Left atrium

Where is the aorta located relative to the left atrium

Posterior

What structure is seen in the right ventricle

Moderator band

Where does the foramen ovale flap open

Into the left atrium

What view is this?

5 Chamber view

What additional structure is seen in the 5-chamber view

Aorta arising from the left ventricle

What is the purpose of the 5-chamber view

Evaluate aortic root and interventricular septum

1. Right ventricle

2. Left ventricle

3. Right atrium

4. Aorta

5. Left atrium

6. Descending aorta

What does LVOT stand for

Left ventricular outflow tract

What vessel arises from the left ventricle in LVOT

Aorta

What is the "ballerina foot" sign associated with

LVOT view

What abnormality can be assessed in LVOT

Ventricular septal defect (VSD)

1. Right ventricle

2. Aorta

3. Left atrium

4. Left ventricle

What does RVOT stand for

Right ventricular outflow tract

What vessel arises from the right ventricle

Pulmonary artery

What structures are seen after the pulmonary artery in RVOT

Ductus arteriosus and right pulmonary artery

What are common descriptors for RVOT appearance

Snail or walking man

1. MPA

2. Right ventricle

3. Aorta

4. Right atrium

5. Right pulmonary artery

6. Ductus Arteriosus

How does the pulmonary artery compare in size to the aorta

Equal or slightly larger

What happens to the great vessels during development

They spiral 180°

What is the normal relationship between the pulmonary artery and aorta

Pulmonary artery crosses over the aorta

In LVOT, what direction does the aorta travel

Left to right

In RVOT, what direction does the pulmonary artery travel

Right to left

What direction should blood flow in both the aorta and pulmonary artery

Away from the transducer toward the spine

How should normal blood flow appear

Smooth and laminar

1. Pulmonary artery

2. Aorta

A= LVOT

B= RVOT

What is the shape of the aortic arch

Candy cane (tight curve)

What branches arise from the aortic arch IN ORDER

Brachiocephalic, left common carotid, left subclavian

1. Ascending aorta

2. Innominate/brachiocephalic artery

3. Left common carotid

4. Left subclavian artery

5. Isthmus

6. Descending AO

What is the shape of the ductal arch

Hockey stick (wide curve)

How many branches does the ductal arch have

None

1. Right ventricle

2. Pulmonary artery

3. Ductus arteriosis

4. Descending aorta

What vessels are seen in the 3 vessel view

SVC, aorta, pulmonary artery

Which vessel is smallest in 3VV

SVC

Which vessel is largest in 3VV

Pulmonary artery

How should the pulmonary artery compare to the aorta

Equal or larger

1. Pulmonary artery

2. Aorta

3. SVC

1. Pulmonary artery

2. Aorta

3. SVC

4. Trachea

1. Pulmonary artery

2. Ascending aorta

3. SVC

4. Trachea

5. Azygous

What structure connects the aorta and pulmonary artery in 3VTV

Ductus arteriosus

Where is the trachea located relative to the aorta

To the right

What direction should flow be in 3VTV

Away from the transducer

What vessels are seen entering the right atrium in the bicaval view

SVC and IVC

1. SVC

2. Right Atrium

3. IVC

How should the SVC and IVC compare in size

Similar caliber

What does the azygous vein drain

Thoracic and abdominal walls

1. Aorta

2. Azygous vein

3. Aorta

4. Azygous vein

Where does the azygous vein empty

Into the SVC

Where might the azygous vein be seen

Parallel to the aorta or joining SVC in 3VT