Download Conotruncal Cardiac Defect

Conotruncal Cardiac Defects:
Recognition on Fetal Ultrasound
R. Dennis Steed, MD
Associate Professor
Department of Pediatrics
Division of Pediatric Cardiology
East Carolina University – Brody School of Medicine
Greenville, NC
Conotruncal Cardiac Defect:
 A cardiac defect occurring early in
development, involving faulty septation or
connection of heart’s chambers and/or the
major blood vessels leaving the heart.
The 4 Most Common Conotruncal Defects:
frequency ( per 100,000 live births)
Tetralogy of Fallot
38
Transposition of the Great Arteries
25
Double Outlet Right Ventricle
11
Truncus Arteriosus
6
Tetralogy of Fallot:
The 4 features typical of tetralogy of Fallot include:
1. Right ventricular (RV) outflow tract obstruction
(RVOTO) (infundibular and valvar)
2. A large ventricular septal defect (VSD)
3. Aortic dextroposition resulting in aortic override of
the VSD
4. Right ventricular hypertrophy
Tetralogy of Fallot:
Diagnostic features on fetal ultrasound
1. The main pulmonary artery will be
smaller than the aorta.
2. Large outlet VSD.
3. The overriding relationship of the aorta
to the VSD.
Transposition of the Great Arteries:
Diagnostic features on fetal ultrasound:
1.
The great arteries are relatively parallel as compared to
near perpendicular relationship in a normal heart.
2. Continuity of the anterior mitral leaflet with the
posterior wall of the pulmonary artery.
3. The more anterior position of the aorta within the chest
results in a rather elongated appearance of the aortic
arch.
Distinguishing features between the
Aorta and the Main Pulmonary Artery:
1. The first branch off the MPA courses directly to the right (
right pulmonary artery)
2. The first branch off the aorta courses superiorly
(innominate artery)
3. The MPA is considerably shorter than the ascending aorta,
ie. The distance from the pulmonary valve to the right
pulmonary artery is considerably shorter than the distance
from the aortic valve to the innominate artery.
Double Outlet Right Ventricle:
1. Both great arteries arise wholly or
predominantly from the morphologic right
ventricle.
2. Multiple anatomic variants based on:
a. The relationship of the great arteries (normally related
or transposed.)
b. The relationship of the VSD to the great arteries ( A
large subarterial VSD is almost always present).
Double Outlet Right Ventricle:
Diagnostic features on fetal ultrasound:
1. Both great arteries arise predominantly from the
morphologic right ventricle.
2. There is infundibular muscle separating the anterior mitral
leaflet from the artery which the artery which is anatomically
closest to the left ventricle.
3. A large sub-arterial VSD is present in the vast majority of
cases.
Truncus Arteriosus:
A single arterial trunk arises from the
ventricles with a single semilunar valve
and typically overides a large VSD.
Truncus Arteriosus:
Diagnostic Features on Fetal Ultrasound:
1. A single great artery
2. Large subarterial VSD ( the Truncus overides the VSD)
3. A short main pulmonary artery and the branch pulmonary
arteries can be identified arising from the truncus just above
the truncal valve.