History
History of double outlet right ventricle (DORV) varies based on type of anatomy.
-
Subaortic or subpulmonary ventricular septal defect (VSD) with pulmonary stenosis
These children present with histories similar to those of children with tetralogy of Fallot.
If pulmonary oligemia is present, severe cyanosis is seen in the newborn period, and the condition is recognized early.
Beyond the newborn period, cyanosis may be accompanied by hypercyanotic spells, polycythemia, and failure to thrive.
These children are less likely to develop pulmonary obstructive vascular disease due to limitation of blood flow and pressure by pulmonary stenosis.
-
Subaortic VSD without pulmonary stenosis
These children present with histories similar to those of children with a large VSD and pulmonary hypertension.
Oxygenation is relatively normal, and patients usually present with congestive heart failure (CHF) and failure to thrive.
Referral usually occurs later unless associated left heart lesions are present.
These children may have associated chromosomal abnormalities such as trisomy 13 or 18.
These children are likely to acquire pulmonary obstructive vascular disease without surgical repair, especially if the VSD is large.
-
Subpulmonary VSD without pulmonary stenosis
These children present with histories similar to those of children with transposition of the great arteries.
Cyanosis varies, with oxygen saturations ranging from 40-80%.
If associated coarctation or interruption of the aorta is present, earlier onset of CHF can be expected to result in earlier referral.
Physical Examination
Physical examination findings vary with the anatomy.
-
Subaortic or subpulmonary VSD with pulmonary stenosis: Physical examination reveals prominent right ventricular impulse, systolic thrill at left upper sternal border, harsh systolic murmur, and a single second heart sound.
-
Subaortic VSD without pulmonary stenosis
Physical examination reveals hyperdynamic precordial impulse, a grade III-IV/VI holosystolic murmur, a loud pulmonary component of the second heart sound, an apical diastolic rumble, and, sometimes, a palpable thrill.
Once these children acquire pulmonary obstructive vascular disease, they exhibit decreased pulmonary blood flow with subsequent loss of the diastolic rumble and attenuation of systolic murmur. They may also develop a loud second heart sound and a diastolic decrescendo murmur of pulmonary insufficiency.
-
Subpulmonary VSD without pulmonary stenosis
Physical examination reveals cyanosis, tachypnea, grunting, and signs of CHF.
Examination also reveals a loud pulmonary component of the second heart sound, a III/VI systolic murmur, and an apical diastolic rumble.
If coarctation of aorta is present, the examination also reveals diminished femoral pulses.
Causes
As with other conotruncal heart defects, the cause of double outlet right ventricle may be of neural crest origin. [4] The neural crest is involved in the development of the cardiac septum. Studies indicate removal of the neural crest during development results in outflow tract malformations, and total removal of cardiac neural crest usually results in truncus arteriosus abnormality. Deletions of smaller parts of the cardiac neural crest result in malformations such as double outlet right ventricle, tetralogy of Fallot, and Eisenmenger complex. Interestingly, neural crest ablation rarely results in transposition of the great arteries. Most changes in heart morphology occur while the heart is still in the looped tube stage.
In addition to formation of cardiac structures, this area of neural crest cells participates in formation of the thymus and the thyroid and parathyroid glands, serving as the basis for association of congenital heart diseases (CHDs) with DiGeorge syndrome. The combination of velocardiofacial syndrome, DiGeorge syndrome (facial anomalies and parathyroid/thymus aplasia or hypoplasia), and a chromosome band 22q11 deletion is known as CATCH 22. [5, 6, 7]
The most common types of CHD associated with the band 22q11 deletion include tetralogy of Fallot, truncus arteriosus, VSDs, and aortic arch abnormalities. [5, 6, 7] Research has shown that 22q11 deletions are rare in double outlet right ventricle. In one study, only 1 in 20 patients with double outlet right ventricle had the deletion; double outlet right ventricle was defined only by lack of fibrous continuity between mitral and aortic valves and an aorta that arises more than 50% above the right ventricle. [7] However, because double outlet right ventricle encompasses such a large spectrum of anomalies, recommendations are to continue to test patients for the 22q11 deletion, especially when they display other features of velocardiofacial syndrome.
-
Neonate with double outlet right ventricle. Chest radiograph shows a mildly enlarged heart with symmetrically slightly increased pulmonary vasculature.
-
Double outlet right ventricle with subaortic ventricular septal defect. Arrow shows flow of oxygenated blood from left ventricle to aorta.
-
Repair of double outlet right ventricle with subaortic ventricular septal defect.
-
Double outlet right ventricle with subpulmonary ventricular septal defect (Taussig-Bing anomaly).
-
Complex repair of double outlet right ventricle with subpulmonary ventricular septal defect.
-
Double outlet right ventricle with doubly committed ventricular septal defect.
-
Repair of double outlet right ventricle with doubly committed ventricular septal defect showing VSD patch and intraventricular baffle.
-
Double outlet right ventricle with noncommitted ventricular septal defect.
-
Repair of double outlet right ventricle with noncommitted ventricular septal defect using a long ventricular septal defect patch.
