Double Outlet Right Ventricle, With
Background: Double outlet right
ventricle (DORV) is a type of ventriculoarterial connection in which both
the aorta (AO) and pulmonary artery (PA) arise entirely or predominantly
from the right ventricle (RV). The only outlet from the left ventricle (LV)
is a ventricular septal defect (VSD). DORV is usually associated with
concordant atrioventricular (AV) connections (ie, the right atrium drains
into the RV and the left atrium drains into the LV). Fibrous discontinuity
is present between the mitral and semilunar valves, which is referred to
as subpulmonic and subaortic conus.
DORV is virtually always associated with a VSD
and occasionally with an atrial septal defect. Patients with DORV may also
present with varying degrees of left ventricular hypoplasia and mitral
valve anomalies such as stenosis or atresia. Straddling of the AV valves
across the VSD may be present. The aortic valve may be stenosed, and the
aortic arch may show coarctation or even interruption. Anomalies of the
coronary arteries (CA) such as those that occur in patients with dextro-transposition
of the great arteries (D-TGA) may be present. These include the left
circumflex arising from the right main, a single right CA, a single left
CA, and inverted origin of the CA.
Finally, the AV node and His-Purkinje fibers may
be displaced in DORV because of the anatomic characteristics of these
In DORV, the great arteries may take different
relationships as follows:
- In 64% of cases of DORV, the great arteries
lie side by side with the AO to the right of the PA and both semilunar
valves lying in the same transverse and coronal plane (physiologically
similar to tetralogy of Fallot [TOF]).
- In 26% of cases of DORV, the AO is anterior
and to the right of the PA, physiologically resembling transposition
of the great arteries (TGA), ie, D-TGA, with a VSD.
- In 7% of cases of DORV, the AO is anterior and
to the left of the PA (left transposition of great artery [L-TGA]).
- Only 3% of cases of DORV have a normal great
artery relationship with the AO arising posterior and to the right of
pathophysiology of DORV is variable, irrespective of the great arterial
relationship (ie, side by side, D-TGA, L-TGA, normally related). Clinical
manifestations may range from that of a large VSD to that of TGA and
depend mostly on the position of the VSD in relation to the great vessels
(whether it is subpulmonary or subaortic) and the presence or absence of
pulmonary valve stenosis (PS). Both of these factors contribute
substantially to the hemodynamics of this congenital heart defect.
In cases of a subaortic VSD, which occurs in
60-70% of patients, the VSD is closer to the aortic valve, thus oxygenated
blood from the LV is directed to the AO and desaturated blood from the
right atrium (RA) is directed primarily to the PA (see Image 1). PS occurs
commonly and directs some desaturated blood into the AO. Because of the
large VSD, the RV and the LV as well as the AO handle equal systolic
pressures. When PS is present, this poses a restriction to flow to the
pulmonary circuit, and thus, systolic pressure in the pulmonary arteries
is lower. This physiology resembles that of TOF with cyanosis and no
congestive heart failure (CHF).
In cases of a subaortic VSD with no PS, systolic
pressure in both great vessels as well as in both ventricles is equal;
thus, blood follows the path of least resistance (ie, usually towards the
lungs) and the clinical picture is that of a large VSD. The degree of
blood oxygenation in the systemic as well as the pulmonary circuits is
determined by degree of mixing in the systemic (ie, right) ventricle,
which in turn depends on the degree of resistance upstream of the
All patients with elevated pulmonary blood flow (PBF)
at systemic or near systemic pressures are at increased risk of developing
early pulmonary obstructive vascular disease regardless of their arterial
oxygen saturation (ie, presence or absence of cyanosis).
With a subpulmonary VSD (Taussig-Bing anomaly),
which occurs in 10% of patients, oxygenated blood from the LV is directed
to the PA and desaturated blood from the RA is directed to the AO. This
physiology resembles TGA with a VSD; thus, the patient presents with
cyanosis and CHF.
In cases of a doubly committed VSD, the left
ventricular outflow is not committed preferentially to either semilunar
valve. In the presence of PS, the physiology resembles that of TOF, and in
the absence of PS, it is that of a large VSD.
In remote VSD, the VSD is far from both semilunar
valves. It is most commonly an AV canal-type VSD. Again, the physiology is
that of TOF in cases involving PS and is that of a large VSD when flow
through the pulmonary valve is not restricted (ie, absence of PS).
- In the US: Congenital heart
disease (CHD) occurs in less than 1% of all newborns, and DORV is
present in 0.5-1.5% of all patients with CHD. The estimated frequency
of DORV is 1 case per 10,000 live births.
DORV and truncus arteriosus occur with a
higher incidence in the offspring of mothers with diabetes mellitus
than in the general population. Teratogenic mechanisms involved are
obscure, although in pregnant diabetic rats, antioxidant
supplementation with vitamin E reduced the severity of malformations
in their offspring.
and morbidity are dependent not only on the overall clinical condition of
the patient but also on the type and severity of associated anomalies.
- Irrespective of the great vessel relationship,
the mortality rate is less than 5% for simple subaortic VSD and is
somewhat higher for a doubly committed VSD.
- In cases of subpulmonary VSD (Taussig-Bing
anomaly), morbidity and mortality depend on whether the patient has
already developed pulmonary vascular obstructive disease and also on
the type of surgery that is required. In cases of DORV with D-TGA,
creation of an intraventricular tunnel between the VSD and the AO
carries a mortality risk of 10-15%. In subpulmonary VSD with PS (ie,
TOF-type physiology), an intraventricular tunnel between the VSD and
the AO in addition to relief of PS by a patch graft also carries a
mortality risk of 10-15%. In cases of remote VSD, the preferred
surgical repair is creation of an interventricular tunnel between the
VSD and the AO. However, it carries a mortality rate as high as
- When the above surgical procedures cannot be
performed (ie, hypoplastic LV, inadequate anatomy for an intracardiac
conduit between the LV and the AO, hypoplastic AO, hypoplastic mitral
valve), a Fontan-type operation is the choice; the mortality rate has
decreased to approximately 5%.
Sex: No sex predilection is
Age: Newborns usually present
with this entity; however, in some circumstances such as subaortic VSD
with mild-to-moderate PS, the diagnosis may not be made until later in
History: History of fetal
bradycardia heart block during the first trimester of pregnancy has been
associated with DORV (as opposed to autoimmune causes of fetal heart
block, which occur after the second and third trimesters). Fetal heart
block can be diagnosed ultrasonographically depending on the subtype of
DORV (eg, with or without TGA); clinical history differs. In patients with
DORV and TGA, the clinical presentation depends on the location of the VSD
and the presence of PS, the degree of PS, or both.
- If the VSD is subpulmonic, the physiology
resembles that of TGA with VSD. Patients with this anatomy usually
present in the newborn period or within the first few weeks of life
with cyanosis and signs of pulmonary overcirculation.
- If the VSD is subaortic, the patient may be
only mildly cyanotic and may present primarily with pulmonary
overcirculation at 3-6 weeks of life when pulmonary vascular
resistance drops. If PS is present (which often is the case in DORV
with subaortic VSD), the degree of PS greatly affects clinical
- If PS is mild or moderate, the patient may
present with mild cyanosis and little or no pulmonary
- If PS is severe, clinical presentation
resembles that of TOF. Cyanosis from diminished PBF is likely to be
the major clinical feature.
- In patients with DORV and TGA (both uncommon
lesions), the VSD may be doubly committed or remote from the great
- If the VSD is doubly committed, the conus
septum is deficient and the VSD usually lies above the crista
supraventricularis closely related to both semilunar valves.
Clinical presentation often is that of DORV with a subpulmonic VSD,
although the patient may have slightly higher systemic oxygen
- In DORV with TGA and remote VSD, many
variables determine clinical presentation. If the VSD is remote from
both semilunar valves, it often is part of an AV canal-type defect,
in which case many other anomalies are likely.
- Alternatively, multiple muscular VSDs may be
remote from the semilunar valves. Clinical presentation depends on
factors such as the location of the VSDs, the presence or absence of
PS (right ventricular outflow tract obstruction), and the direction
of streaming of blood flow through VSDs.
Physical: Physical findings
vary, depending on the location of the VSD and the presence or absence of
- With a subaortic VSD and no PS, cyanosis is
mild or absent.
- PBF is increased, thereby producing CHF.
- The precordium is hyperactive with a loud
second heart sound, which may appear to be single.
- Harsh regurgitant systolic murmur is heard
as pulmonary vascular resistance decreases.
- Clinically, these patients resemble those
with a large VSD.
- In DORV with subaortic VSD and PS, physical
findings depend on the degree of PS.
- If PS is mild, little cyanosis and only mild
CHF may be present.
- These patients present with a murmur from PS
(systolic ejection murmur), from the VSD (regurgitant murmur), or
- If PS is moderate or severe, cyanosis is
prominent because of decreased PBF (resembling TOF).
- If uncorrected, cyanosis leads to late
findings such as polycythemia and digital clubbing.
- In those patients with subpulmonic VSD (PS is
rare in these patients), PBF increases as vascular resistance falls.
- These patients present similarly to those
with TGA and VSD.
- Cyanosis is prominent early, and pulmonary
- Failure to thrive is likely to develop if
treatment is not instituted.
- The second heart sound is loud and possibly
single, and a regurgitant systolic murmur develops.
- If increased pulmonary vascular resistance
occurs, signs of CHF diminish and the murmur decreases.
- An ejection click may appear along with a
diastolic murmur of pulmonary valve insufficiency (late findings).
- Patients with doubly committed VSD also
present similarly to those with TGA and VSD.
- Signs of CHF, including tachypnea,
tachycardia, and hepatomegaly, lead to failure to thrive.
- DORV may be part of complex CHD in patients
with DiGeorge, velocardiofacial, and conotruncal anomaly-face
syndromes. It has also been associated with trisomies 13 and 18 and
- DORV may be associated with other organ-system
defects, such as omphalocele, gastroschisis, facial clefting, and
CHARGE (coloboma, heart disease, atresia choanae, retarded growth and
retarded development and/or CNS anomalies, genital hypoplasia, and ear
anomalies and/or deafness syndrome).
- DORV has recently been reported to occur in
mouse embryos homozygous for the JMJ mutation, which affects
the nuclear protein jmj coded by chamber-specific genes.
- DORV has also been reported in patients with
mutations in human cardiac transcription factor NKX2.5.
Ventricular Septal Defect, General Concepts
Other Problems to be Considered:
Distinguish DORV (with or without TGA) and
subaortic VSD from VSD.
PS may have a presentation similar to that of TOF.
Subpulmonary VSD without PS may have a presentation similar to that of TGA
- Clinical laboratory studies (ie, hematologic
analysis, urinalysis) are not likely to be of diagnostic help; late
findings may include polycythemia, but this and other findings of
chronic cyanosis are nonspecific.
- Echocardiography is used to evaluate anatomy,
hemodynamics, and function of the heart after surgical repair or
palliation, and it is the most important means of establishing
diagnosis of DORV with TGA. Four important findings to determine DORV
are as follows:
- Both great arteries arise from the RV.
- AO is to the right of or anterior to the PA.
- No course of egress of blood from the LV
other than a VSD is present.
- Discontinuity of mitral and semilunar valves
- Chest radiography may provide valuable clues
for the diagnosis of DORV with TGA.
- Chest radiography for patients with either
subaortic or subpulmonary VSD without PS shows cardiomegaly with
increased pulmonary vascular markings; the main PA segment may be
prominent. These findings are not specific for DORV.
- If PS is present, chest radiography shows a
normal heart size and normal-to-decreased pulmonary vascular
- Magnetic resonance imaging (MRI) may serve as
an adjunct tool to echocardiography for determination of visceral and
atrial situs, although it is rarely used as a primary diagnostic tool
for infants with suspected CHD. In some patients with DORV with remote
VSD, MRI may aid in defining the spatial relationship between VSD and
the semilunar valves.
- Angiography may add anatomic and physiologic
details to information found by echocardiography.
- ECG in patients with DORV with TGA shows no
- Usually, normal sinus rhythm and possible
prolonged P-R interval are present. Right axis deviation and right
ventricular hypertrophy (RVH) are likely to be present.
- In the absence of these findings, question
the diagnosis or consider special circumstances such as an
associated AV canal if left axis deviation is present.
- Some ECG variations may exist depending on
the variety of DORV with TGA.
- ECG in patients with subaortic VSD with
no PS may show superior QRS axis (-30° to -170°) with either
RVH or biventricular hypertrophy and left atrial enlargement.
First-degree AV block may be present with this lesion.
- ECG in patients with subpulmonic VSD or
in those with subaortic VSD and PS shows right axis deviation,
RVH, and often right atrial enlargement.
- Echocardiography has mostly eliminated the
need to perform cardiac catheterization in these patients; however,
catheterization may still be necessary in certain circumstances.
Catheterization may be required for the following reasons:
- Need for further definition of coronary
- Need to determine coexistent conditions that
cannot be elucidated by echocardiography
- Need to confirm restrictive VSD by measuring
- Need to determine pulmonary vascular
resistance (and reactivity) in patients suspected of having
Medical Care: Direct medical
treatment depends on the clinical presentation, which is determined by the
different physiology of each type of DORV.
- In DORV with no PS, direct medical management
at reducing CHF to improve the patient’s condition prior to surgery.
Management of CHF requires medications such as loop diuretics (eg,
furosemide), potassium-sparing diuretics (eg, spironolactone), and
digitalis. In addition, observe subacute bacterial endocarditis
- Infants with a subpulmonary VSD with a small
or restrictive patent foramen ovale or atrial septal defect may
require balloon atrial septostomy or blade atrial septostomy to
improve interatrial mixing of saturated and desaturated blood and to
decompress the left atrium.
- In patients with DORV and PS with marked
cyanosis and hypoxemia, initial medical management consists of
increasing the fraction of inspired oxygen (FIO2), which
may be up to 100%. This decreases pulmonary vascular resistance,
thereby increasing the amount of blood flow in the lungs with
consequent increase in overall organ oxygenation.
Surgical Care: Two surgical
approaches are appropriate, depending on the degree of CHF.
- As with medical treatment, this approach
helps improve the patient's clinical condition, allowing him or her
to gain weight to achieve optimal conditions for definitive surgical
- Infants with no PS who have a subpulmonary
VSD, subaortic VSD, or doubly committed VSD and who present with CHF
may undergo PA banding to decrease PBF.
- Patients with subaortic or subpulmonary VSD
with PS are cyanotic and have decreased PBF; therefore, perform a
systemic-to-PA shunt to increase PBF.
- The relationship of VSD to the great
arteries and the distribution of CA determine surgical strategies.
- Biventricular repair can be achieved in most
patients with DORV. If biventricular repair is not feasible (eg, in
straddling or abnormal distribution of chordae tendineae of AV
valves and/or severe underdevelopment of LV), a Fontan-type
operation is an option with redirection of systemic (deoxygenated)
blood into the PA without traversing a ventricle.
- Several surgical approaches are appropriate
in subpulmonary VSD; surgery is usually completed by age 3-4 months
to avoid development of increased pulmonary vascular resistance. The
surgical approach with the lower mortality rate of approximately
10-15% is the arterial switch operation with creation of an
interventricular tunnel directing LV outflow into the PA, which
becomes a neo-AO by virtue of the switch.
- If the VSD is subaortic or doubly committed,
the optimal approach is to create a tunnel between the VSD and the
AO to direct oxygenated blood into systemic circulation and also to
eliminate mixing of the 2 circulations. Timing for this surgery
depends on the size and clinical condition of the patient, but it is
generally completed by age 4-6 months.
- Heart transplantation: If the anatomy of
associated lesions is too complex to consider an anatomic repair or if
a repair results in unsatisfactory hemodynamics and intractable
symptoms, consider heart transplantation. In a recent report from the Children’s
Hospital of Pittsburgh, 15.4% of patients undergoing transplant
were born with some form of DORV. These patients require lifelong
immunosuppression and close follow-up care.
Consultations: As with any other
form of CHD, parents of patients born with DORV and TGA may meet with a
geneticist to discuss the possibility of subsequent children having this
or other forms of CHD.
- Patients with DORV and TGA have no specific
activity restrictions; their physiology may limit their exercise
tolerance. After surgical intervention, some restrictions may be
required depending on the hemodynamic result; however, these patients
can usually participate in all age-appropriate activities.
- Lifelong antibiotic prophylaxis is necessary
prior to any potentially contaminated procedure, especially dental
Medical therapy is aimed at alleviating CHF, when
present, to prepare patients for surgery.
Drug Category: Loop diuretics
-- Furosemide is used to decrease pulmonary congestion in patients
with pulmonary overcirculation.
Drug Category: Potassium-sparing
diuretics -- Potassium-sparing diuretics (eg, spironolactone)
are weak diuretics usually prescribed with more potent loop diuretics to
prevent potassium depletion with subsequent development of
hypokalemic-hypochloremic metabolic alkalosis.
(Lasix) -- Inhibits absorption of sodium and chloride in proximal
and distal tubules of the loop of Henle, thereby promoting
excretion of salt and water.
mg/d PO/IV divided q6-12h; not to exceed 600 mg/d
mg/kg/dose PO/IV/IM q8-24h; not to exceed 6 mg/kg/d PO or 2
hypersensitivity; hepatic coma; anuria; severe electrolyte
muscle-relaxing effect of tubocurarine; auditory toxicity appears
to be increased with coadministration of aminoglycosides and
furosemide; hearing loss of varying degrees may occur;
anticoagulant activity of warfarin may be enhanced when taken
concurrently with this medication; increased plasma lithium levels
and toxicity are possible when taken concurrently with this
Safety for use during pregnancy has not been established.
ototoxic in patients with oliguria; may cause electrolyte
imbalance with hypokalemic-hypochloremic metabolic alkalosis,
hyponatremia, hypomagnesemia, and hypocalcemia; prolonged use in
premature infants may precipitate nephrocalcinosis from
hypercalciuria; these effects can be avoided by concomitant use of
potassium-sparing diuretics (eg, spironolactone)
Drug Category: Inotropic agents
-- Positive inotropic agents increase the force of contraction of
the myocardium and are used to treat acute and chronic CHF. Some may also
increase or decrease the heart rate (ie, positive or negative chronotropic
agents), provide vasodilatation, or improve myocardial relaxation. These
additional properties influence the choice of drug for specific
circumstances. Those used predominantly for their inotropic effects
include cardiac glycosides. Digitalis glycosides are used for their
inotropic properties in the presence of left ventricular failure.
(Aldactone) -- Inhibits aldosterone-dependent sodium-potassium
exchanger in distal convoluted renal tubule, thereby retaining
potassium and promoting excretion of sodium and water.
mg/d PO divided bid/qid; not to exceed 200 mg/d
mg/kg/d PO divided bid/qid; not to exceed 200 mg/d
hypersensitivity; anuria; renal failure; hyperkalemia
potentiate antihypertensive drugs; may provoke severe hyperkalemia
when administered with ACE inhibitors or indomethacin; increases
half-life of digoxin, thereby augmenting its risk of toxicity
Unsafe in pregnancy
mild metabolic acidosis, GI distress, rashes, and gynecomastia;
few cases of agranulocytosis have been reported; caution in renal
and hepatic impairment
Lanoxicaps) -- Digitalis glycoside. Enhances myocardial
contractility by inhibition of Na+/K+ ATPase,
a cell membrane enzyme that extrudes Na and brings K into the
myocyte. Resulting increase in intracellular Na stimulates Na-Ca
exchanger in the cell membrane, which extrudes Na and brings in
Ca, therefore increasing contractility of myocyte (ie, positive
10-15 mcg/kg/d PO divided tid for 3 doses (typically 0.75-1.5 mg
8-12 mcg/kg/d IV/IM divided tid for 3 doses (typically 0.5-1 mg
2.5-5 mcg/kg/d PO (typically 0.125-0.5 mg/d)
2-3 mcg/kg/d IV/IM (typically 0.1-0.4 mg/d)
digitalizing dose (TDD):
Premature infants: 0.02 mg/kg PO divided q8h
Full-term infants: 0.03 mg/kg PO divided q8h
1-24 months: 0.04-0.05 mg/kg PO divided q8h
>24 months: 0.03-0.04 mg/kg PO divided q8h
Infants: 6-8 mcg/kg/d PO bid dosing is recommended
2-5 years: 10-15 mcg/kg/d PO bid dosing is recommended
5-10 years: 7-10 mcg/kg/d PO bid dosing is recommended
>10 years: 3-5 mcg/kg/d PO
Therapeutic concentration 0.8 - 2 = ng/mL
hypersensitivity; beriberi heart disease; idiopathic hypertrophic
subaortic stenosis; constrictive pericarditis; carotid sinus
calcium may produce arrhythmias in digitalized patients;
medications that may increase digoxin levels include alprazolam,
benzodiazepines, bepridil, captopril, cyclosporine, propafenone,
propantheline, quinidine, diltiazem, aminoglycosides, PO
amiodarone, anticholinergics, diphenoxylate, erythromycin,
felodipine, flecainide, hydroxychloroquine, itraconazole,
nifedipine, omeprazole, quinine, ibuprofen, indomethacin, esmolol,
tetracycline, tolbutamide, and verapamil; medications that may
decrease serum digoxin levels include aminoglutethimide,
antihistamines, cholestyramine, neomycin, penicillamine,
aminoglycosides, PO colestipol, hydantoins, hypoglycemic agents,
antineoplastic treatment combinations (including carmustine,
bleomycin, methotrexate, cytarabine, doxorubicin, cyclophosphamide,
vincristine, and procarbazine), aluminum or magnesium antacids,
rifampin, sucralfate, sulfasalazine, barbiturates, kaolin/pectin,
and aminosalicylic acid
Safety for use during pregnancy has not been established.
of digitalis intoxication include changes in cardiac rhythm,
especially induction of ectopic pacemakers and impaired conduction
(eg, complete heart block), GI symptoms (eg, anorexia, nausea,
emesis), and other symptoms (eg, fatigue, weakness, blurred
vision, aberrations of color vision, headache, somnolence,
disorientation, seizures); patients with deceased renal function
and those with hypokalemia, hypomagnesemia, and hypercalcemia may
reach toxic levels at lower doses; in patients with
Wolff-Parkinson-White who develop atrial flutter or fibrillation,
treatment with digoxin rarely may provoke ventricular fibrillation
by increasing antegrade conduction through accessory pathway; if
cardioversion or calcium infusion is required, administer
lidocaine first to avoid possibility of ventricular fibrillation
Further Inpatient Care:
- Maintain patency of the ductus arteriosus with
prostaglandin E1 in newborns with markedly diminished PBF from severe
PS. In newborns with DORV and TGA who have subpulmonic VSD, performing
balloon atrial septostomy to enhance mixing of systemic and pulmonary
circulations until surgery can be performed may be necessary.
Further Outpatient Care:
- Provide follow-up care every 6-12 months for
the first few years after surgery to detect complications of surgery
that may include arrhythmias (eg, persistent atrial tachycardias,
complex ventricular ectopy) and stenosis or partial obstruction, or
both, of the interventricular tunnel.
- Because arrhythmias result in morbidity,
mortality, or both, patients may require long-term antiarrhythmic
medication or may be candidates for radiofrequency ablation of an
arrhythmogenic focus or circuit.
- Interventricular tunnel obstructions may
occur without clinical manifestations. In patients with severe left
ventricular outflow obstruction, patients with tunnel obstruction
may present with left ventricular failure. As many as 20% of
patients who have undergone surgery for DORV require reoperation.
- In all patients, subacute bacterial
endocarditis prophylaxis is required.
- Because surgery in these patients often is
technically demanding, strongly consider referring these patients to a
center with a large pediatric cardiac surgical program.
- Improvement in surgical techniques in recent
years has resulted in good outcomes for most patients born with CHD.
Prognosis for infants born with DORV and TGA generally is good,
although it is dependent on specific anatomy. For example, patients
with DORV and TGA with a subaortic VSD and no other anatomic
abnormalities (eg, left ventricular hypoplasia) are likely to do well
after surgery. Patients with restrictive VSD may not do as well
because this is a particularly difficult problem. Enlargement of VSD
is difficult and likely to result in complications, such as conduction
abnormalities (AV block).
- Medicolegal pitfalls in caring for patients
with DORV and TGA are similar to those for any patient with CHD.
- Failure to make the correct diagnosis is of
paramount importance. The correct treatment plan can be determined
only if all anatomic details are known. Misdiagnosis can lead to
- The second issue is surgery. Because most of
these patients do well when care is administered at a center with
considerable experience in caring for infants with CHD, referral to
such a center provides the best opportunity for a good long-term
- The physician must be familiar with the
possible complications that may result from surgery and be able to
treat complications resulting from surgery appropriately.
- Subaortic or subpulmonary VSD without PS: If
left unrepaired, these infants develop CHF from pulmonary
overcirculation, which evolves into pulmonary vascular obstructive
- Subaortic or subpulmonary VSD with PS: If left
untreated, complications develop, including cyanosis (ie, polycythemia),
which can lead to stroke.
Picture 1. Double outlet right ventricle (DORV) with transposition
of great arteries accounts for 26% of cases of DORV. The aorta
(AO) is anterior and to the right of the pulmonary artery (PA),
and both arteries arise from the right ventricle (RV). The only
outflow from the left ventricle (LV) is a ventricular septal
defect (VSD), which diverts blood toward the RV. Pulmonary veins
drain into the left atrium (LA) after blood has been oxygenated in
the lungs (L). Systemic venous return is to the right atrium (RA).
Picture 2. This is an angiogram obtained during catheterization of
a patient with double outlet right ventricle (DORV) with
transposition of great arteries. Injection of contrast though the
catheter (arrow) into the left ventricle (LV) shows that blood is
directed toward the right ventricle (RV) through a remote or
doubly committed ventricular septal defect (VSD). The aorta (AO)
is anterior to the pulmonary artery (PA) and both clearly arise
from the RV.
Picture 3. This is an angiogram obtained during catheterization of
a patient with double outlet right ventricle (DORV) with
transposition of great arteries (see Image 2). Blood fills the
aorta (AO) and pulmonary artery (PA) almost simultaneously, which
is another indicator of a remote or doubly committed ventricular
septal defect (VSD) (curved arrow). LV indicates the left
ventricle, RV indicates the right ventricle, and the small arrow
to the left indicates the catheter.