Embryology Midterm

Are ASD's usually symptomatic in childhood?

Rarely, except in coincidental lung disease

ASD's are more common in __________ (men/women)

women

ASD's are the ______ most common CHD.

3rd

What is potential long-term consequence of an ASD?

Eisenmenger's syndrome - when an ASD causes high blood pressure in the lungs (PHTN)

Types of ASD's

PFO (not rlly), sinus venosus (not rlly), secundum, primum, AV canal, coronary sinus (also not rlly)

What is the limbic band a remnant of?

the septum secundum

What is the most common type of ASD?

secundum ASD

Secundum ASD

inadequate growth (or defective growth) of septum primum (fossa ovalis)

Primum ASD's are associated with...

endocardial cushion defects (partial, transitional, complete)

What is the most common type of sinus venosus defect (SVD)?

absence of tissue between the RUPV and SVC

SVD ultrasound

Sinus Venosus ASDs should be suspected in patients who demonstrate...

unexplained right ventricular volume overload

Coronary Sinus Defect

Unroofing (either complete or partial) of the coronary sinus

Raghib Syndrome

persistent LSVC that drains through the coronary sinus

What do we look for with Echo?

Size, location and number of the defects

Shunt flow direction

Measure with calipers

Multiple views - 2D & 3D

What is its relationship to neighboring structures? (next slide)

SL & AV valves/pulmonary & systemic veins

Evaluate biventricular function

Detect associated lesions

How do we evaluate hemodynamic assessment?

Flow direction (color & spectral Doppler)

Transseptal pressure gradient

How do we evaluate hemodynamic load?

RAE, RVE & MPA/branch dilation

Diastolic septal flattening (D shape MV in PSAX)

Increased pulmonary blood flow

Estimate RVSP

Biventricular systolic function

Pre-atrial level shunts:

Partial anomalous pulmonary venous return (PAPVR)

Atrial level shunts:

ASD's of all sorts

Ventricular level shunts:

VSD's, AV canal, etc.

Great Artery level shunts:

PDA, coronary fistulae, etc.

Crossing levels shunts:

various fistulae, AVM's, LV to RA shunts

Amount of shunting is determined by?

1. Defect size

2. Compliance of the LV and RV

given that there is no AV valve stenosis or hypoplasia

What is a consequence of pre-atrial or atrial left to right shunts?

right heart enlargement

Normal flow volume ratio:

pulmonary:systemic

Qp:Qs = 1

ASD - Qp:Qs = 2:1 (left to right)

Fixed split S2 and pulmonary flow murmur

RA, RV, MPA enlarged

Eisenmenger's Syndrome

ASD creates a left to right shunt

Shunt causes RA & RV enlargement

Over time, the pulmonary vascular system can't handle the extra shunt flow, which increases PA pressure

When the PA pressure exceeds the Aortic pressure, the shunt will now become right to left across the ASD

This leads to: pulmonary hypertension, cyanosis, low CO & death

ASD - Qp:Qs = <1:1 (right to left)

Bidirectional Shunts

Left to right AND right to left shunting at the same level

Qp=Qs

How do they fix an ASD?

Amplatzer or Helix device

What do we look for with Echo...after they fix it?

1. Multiple views of the septum - 2D & 3D

2. Color Doppler to rule out residual ASD flow

3. Evaluate device position

4. Abnormal movement: rocking, flopping or absence of the device all together

5. Impingement of the device on surrounding structures

6. Rule out thrombus or endocarditis in general, and on thedevice as well

7. Estimate RVSP

8. RV size and function - improvement?

Can PFOs cause issues later on?

No they usually won't cause problems down the line

What is a common finding of the IAS in the elderly?

thickening of the muscular septum (not the FO) - dumbbell shape

Ductal dependent lesion

the ductus is the only way the PA or Ao are getting flow (ex. atresia of PV)

What shunt would PHTN cause?

right -> left shunt

What views can you visualize a PFO?

subcostal 4C, bicaval

What do we use to evaluate a shunt?

color, PW

Will the flow through a PFO be high or low velocity?

low

What views can you visualize a sinus venosus ASD?

bicaval, right parasternal

What views can you visualize a coronary sinus ASD?

PLAX, apical 4C (w/ posterior angle)

Label the image:

1. Sinus venosus ASD

2. Secundum ASD

3. Primum ASD

4. Sinus venosus ASD

5. Coronary sinus ASD

Will lungs be able to withstand a shunt that directs double the blood flow through the PA?

Yes actually, they are very compliant - but it won't last forever - PHTN

History

Maternal history of Rubella (similar to measles)

Maternal history of SLE (lupus)

Maternal diabetes

Maternal use of medications

Maternal use of alcohol

Maternal use of smoking

Maternal exposure to radiation

Low birth rate

Prematurity

Familial history

Congenital heart disease

Syndromes

Stillbirths

Spontaneous abortion

Birth history

Progress of labor

Method of delivery

APGAR score (Appearance (skin color), Pulse (heart rate), Grimace (reflex irritability), Activity (muscle tone), and Respiration (breathing effort)

Asphyxia during labor/delivery

Symptoms - Serious CHD

Cyanosis, Tachypnea, Swelling (legs, abdomen), Failure to thrive, Poor weight gain, Feeding difficulties, Colic/irritability, Lethargy, Respiratory distress, Diaphoresis, Clinically significant murmur

Symptoms - "Not-so-Serious" CHD

Shortness of breath with exercise or activity, easily tiring during exercise or activity, fainting/syncope during exercise or activity, palpitations, swelling (hands, ankles, feet), innocent murmur

Signs/Physical Exam

Squatting after exercise or activity

Syndrome identification

Down's syndrome

Skeletal abnormalities

Scoliosis

Pyrexia

Clubbing

Blood pressure

Hypertension

Differences in extremities

Pulses & pulse oximetry

Murmur(s)

Diagnostics

Fetal Echocardiogram

Echocardiogram

Electrocardiogram

Chest X-ray

Pulse Oximetry

Cardiac Catheterization

Cardiovascular Magnetic Resonance Imaging

Computed Tomography

Exercise Stress test (imaging or non-imaging)

Indications & AUC

Failure of 20-week OB/fetal echocardiogram

Failure of any antenatal exam

Abnormal EKG

Chest pain

Congestive heart failure

Cyanosis

Desaturation

Hypertension

Murmur

Syncope

Palpitations

Fatigue

Fever

Chemotherapy

Systemic disorders

Family history of CHD

Maternal history

Obtain the following before every exam:

Height/Length

Weight

Blood pressure

O2 Saturations (when clinically indicated)

When do we use EKGs?

ALL outpatients over the age of 3

Do we use high or low color scale the evaluate the coronaries? What about the valves and shunts?

low; high

Subcostal - transducer position

3 o'clock - transducer in neutral position (not looking up this time)

What is the goal of subcostal?

to establish and document thoracic-abdominal situs

What anatomy do we include in the first subcostal sweep?

Liver, stomach, IVC, abdominal aorta

What pathologies can be identified in the first subcostal sweep?

Interrupted IVC, abnormalities of abdominal visceral situs, pleural effusions

Subcostal Sagittal - transducer position

rotate probe so notch is at 12 o' clock - tilt and sweep from right to left until aorta comes into view

What is the ideal angle of insonation for PW interrogation of the abdominal aorta?

as close to less than or equal to 30 degrees as possible

Subcostal Coronal - transducer position

rotate notch to 3 o' clock and tilt transducer anteriorly (up)

What are we looking for with the posterior to anterior sweep?

Dextrolooping, atrial identity, ventricular identity, AV connections

What other anatomy are we evaluating in the subcostal coronal view?

If the atrial septum and ventricular septum is intact

Left Anterior Oblique (LAO) transducer position:

Transducer is midline, notch is to 4:30

Right Anterior Oblique (RAO) transducer position:

Transducer is midline, notch is to 2 o' clock

Which veins do we focus on for venous anomalies?

SVC

IVC

Azygos vein

Hemiazygos vein

Hepatic veins

Coronary sinus

What are the 3 things we should be thinking about with venous anomalies?

Atrial situs - which systemic veins come into which atria

Prevalence - persistent left superior vena cava is most common

Embryology - which veins regress and which veins stay patent and why

vitelline veins

carry blood, oxygen, and nutrients from the yolk sac to the sinus venosus

umbilical veins

carry oxygenated blood from placenta to fetus

cardinal veins

drain deoxygenated blood from the head and body of the embryo to the sinus venosus

anterior cardinal veins

drain cephalic part of embryo

posterior cardinal veins

drain the rest of the embryo

Which vein forms the portal system?

the vitelline vein

Which veins forms the caval system?

cardinal veins, SVC, IVC, brachiocephalic vein

SVC embryologic origin

right anterior cardinal vein

left innominate vein embryologic origin

persistent connection between the anterior cardinal veins after regression of the left cardinal vein

coronary sinus embryologic origin

left common cardinal vein

IVC embryologic origin

right vitelline vein, right hepatocardiac vein, right sub cardinal vein

Hepatic vein embryologic origin

vitelline veins, omphalomesenteric veins

Azygos vein embryologic origin

right supracardinal vein

Hemiazygos vein embryologic origin

left supracardinal vein

Draw the embryologic venous system at Week 6 & 7:

Draw the embryologic venous system at Week 8 & 9:

SVC anomalies

- Left SVC to the coronary sinus with normal right SVC (Bilateral SVC's)

- Left SVC to the coronary sinus with atretic (closed) right SVC

- Left SVC to the left atrium

- Levoatrial cardinal vein

How does a left SVC to the CS form?

because there is failure of regression of the left anterior cardinal and left common cardinal veins

Why is a left SVC to the CS important to be identified?

due to the significant impact on the cannulation approach during cardiopulmonary bypass support if surgical intervention is required (in the setting of CHD)

Where can we view a left SVC to the CS?

in the high left parasagittal view

Ultrasound image of a left SVC to the CS:

What is a levoatrial cardinal vein?

Embryonic connection between the capillary plexus of the embryonic origin of the pulmonary veins and the cardinal venous system (to dumb it down: it provides a connection between the left atrium or pulmonary veins to the systemic veins such as the innominate vein or superior vena)

Why do we think levoatrial cardinal veins occur?

Thought to occur due to the elevated pressures in patient's who have pulmonary venous obstruction.

Decompresses the pulmonary veins by connecting the LA or PVn to the lower pressure right atrium via the SVC or innominate vein

What view is a levoatrial cardinal vein obtained?

Visualized in the suprasternal SAX view

Image of a levoatrial cardinal vein:

Inferior Vena Cava Anomalies

Interrupted IVC with azygos/hemiazygos continuation

Bilateral IVC (duplicate IVC)

Left IVC to Right Atrium

Right IVC to Left Atrium

What is an interrupted IVC withazygos/hemiazygos continuation?

IVC forms from the iliac veins, stops, then blood finds a way to the RA through the azygos/hemazygos vein

What type of patients is interrupted IVC withazygos/hemiazygos continuation most common in?

patients with Heterotaxy syndrome

What causes an interrupted IVC withazygos/hemiazygos continuation?

Due to failure of the right subcardinal vein to connect to the right vitelline and right hepatocardiac veins (absence of hepatic segment of the IVC)

In what view can we obtain an interrupted IVC withazygos/hemiazygos continuation?

Subcostal SAX and LAX with a posterior angle will demonstrate the hepatic veins draining into the RA without a connection to the IVC

Is a bilateral (duplicate) IVC rare?

yes

What causes a bilateral (duplicate) IVC?

persistence of both supracardinal veins

What type of patient is most common to have bilateral (duplicate) IVC?

Heterotaxy syndrome, but also with normal Abdominal Situs

Types of bilateral (duplicate) IVC's & confluences: