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lACC Vol. 9 . No. 4
April 19R7:830-3
Pulmonary Venous Obstruction and Atrioventricular Canal
Anomalies: Role of Cor Triatriatum and Double Outlet Right Atrium
THOMAS J. STARC, MD, FREDRICK Z. BIERMAN , MD, FACC,
FREDERICK O. BOWMAN, JR. , MD, CARL N. STEEG, MD, FACC, NK WANG , MD,
EHUD KRONGRAD , MD, FACC
New York. New York
Two-dimensional echocardiographic findings and surgical repair in three infants with atrioventricular (AV)
canal and pulmonary venous obstruction are described.
The AV canal was complicated by cor triatriatum in two
patients and by double outlet right atrium in the other.
Atriove ntricular (AV) ca nal type defects are often associated
with pulm onary hypertension and the ea rly onset of pulmonary vasc ular ob stru ct ive disease . Anatomic cau ses of
obstru ct ion to pulmonary venous return are rare in these
patients ( I) . Thi s report describ es the two-d imensional echocardiog raphic findings and surgica l management of three
infant s with AV canal and obstruction of pulm onary venous
drai nage . The obstructio n was seco ndary to cor triatr iatum
in two pat ients and seco ndary to doubl e outlet right atrium
in the other.
Case Reports
Case I . Complete AV Canal and Cor Triatriatum
History. A 6 month old boy with failure to thri ve , perioral cya nos is and tach ypnea since the first weeks of life
was referred for ev aluatio n of complete common AV canal
with " irre versible " pulm onary vasc ular obstructive disease .
Cardiac ca theterization at 4 month s of age at the referring
institut ion demonstrated complete AV ca nal with a common
AV valve . Pulmonary and sys temic arte rial systolic pressures were eq ual. A pulm onary artery wedge pressure was
not obtained . There was a small left to right shunt with a
pulm onary to sys temic flow ratio of 1.4/ I . Pulm onary artery
From the Cardiology Division of the Department of Ped iatrics and (he
Card iothorac ic Division o r the Department or Surgery. Co lumbia University. College or Physicians and Surgeons. New York. New York.
Manuscript received May 23 . 1986: revised man uscript received October 21. 1986 . acce pted Nove mbe r 17 . 1986 .
Add ress for reprints: Thom as J. Stare. MD. Co lumbia University.
Co llege of Physicians and Surgeon s. Room BHSI -102A . 630 West 168
Street. New York . New York 10032.
© 1987 by the American Collegeof Cardiology
In patients with AV canal, anatomic ohstruction of pulmonary venous return should be excluded by detailed
cardiac ultrasound examination .
() Am ColI Cardiol 1987;9:830-3)
pressure and pulmonary artery blood flow did not change
administration of oxyge n. The left atrium was not en tered .
AT 6 months of age the infant was thin and tachypneic
with mild cya nosis . The height and weig ht were less than
the fifth percentile for age. Th e precord ium was active. The
second heart sound was loud and single. A grade 3/6 holosystol ic murmur was present at the lower left sternal border. There was no diastol ic murmur. The liver was palpabl e
2 em below the right costa l margin.
Laboratory findings. The chest X-ray film showed a
large heart and increased pulmonary vascular markings. The
electrocardiogram (ECG) showed normal sinus rhythm . right
superior ax is and right vent ricul ar hypertrophy . The PR
interval was 0.14 ms. Two-d imen sional echocardiography
confirmed the diagnosis of co mplete AV ca nal. but also
demonstrated cor triatriatum . In co ntrast to the normal configuration of the interatrial sept um and left atrium (Fig. I),
in this patient a membrane ex tended from the superio r portion of the atrial septum to the lateral left atria l wall inserting
above the left atrial appendage (Fig. 2) . The pulmonary
veins drain ed into a common pulm onary venous chamber
that co mmunicated with the atr ia through a small orifice in
the membrane.
Surgical findings. Surgery at 7 month s of age dem on strated a large right atrium that led directly throu gh a common AV valve into both right and left ventricles. The AV
valve had a divided anterior leaflet and a common poste rior
leaflet. A membrane extending from the midportion of the
common atrium to the left atrial wall just abo ve the left
atrial appendage was ident ified . There was a small opening
in the membrane that allow ed pulm onary venous blood to
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JACC Vo!. 9. No.4
April 19H7:S30~3
Figure 1. Normal infant. Subxiphoid atrial long-axis projection
demonstrating normal configuration of the interatrial septum, left
atrium (LA) and left atrial appendage (LAA). The atria are partitioned by the interatrial septum and the leftatrium is continuous
with the left ventricular inflow (LVI). I = inferior; L = left; R
= right; RA = right atrium; S = superior.
enter the common atrium. The atrial membrane was completely excised and the AV canal was repaired using a double
patch technique. Pericardium was used to partition the atria.
The postoperative course was unremarkableexcept for moderately severe postpericardiotomy syndrome.
Case 2. Partial AV Canal and Cor Triatriatum
History. A 6 month old girl with oral-facial-digital syndrome and partial AV canal was referred for evaluation of
failure to thrive and respiratory distress. On arrival she was
intubated and in moderate respiratory distress. Chest examination revealed bilateral ronchi and wheezes. The precordium was active. The first and second heart sounds were
normal. A grade 2/6 systolic ejection murmur was heard at
the left upper sternal border. There was no diastolic murmur.
The liver was palpable 3 cm below the right costal margin.
Laboratory studies. The chest X-ray film showed a
large heart and increased pulmonary vascular markings. The
ECG showed normal sinus rhythm, a left superior axis and
right ventricular hypertrophy. The PR interval was O. 10 ms.
Two-dimensional echocardiography demonstrated a large
ostium primum type defect and cor triatriatum. A membrane
separated the common pulmonary venous chamber from the
remainder of the left atrium. A small defect was noted in
the membrane and pulsed Doppler echocardiography demonstrated restrictive blood flow across the defect (Fig. 3).
Surgical findings. Surgery confirmed the diagnosis of
partial AV canal and cor triatriatum. In addition, a left
superior vena cava was noted. The opening between the
common pulmonary venous chamber and the remainder of
the atrium was approximately I ern in diameter. Before
STARe ET AL.
AV CANAL AND PULMONARY VENOUS OBSTRUCTION
831
Figure 2. Patient I. Subxiphoid atrial long-axis projection in a
patient with complete AV canal and cor triatriatum. The obstructing membrane extends from the superior portion of the atrial septum and inserts on the lateral left atrial wall, above the left atrial
appendage (LAA). *Atrial septal defect; CPV = common pulmonary vein; RVI = right ventricular inflow; other abbreviations
as in Figure I.
institution of cardiopulmonary bypass, the right ventricular
pressure was 35 mm Hg, systemic arterial pressure was
90/50 mm Hg. right superior pulmonary vein pressure was
5 mm Hg (mean) and 10 mm Hg (ac wave) and mean right
atrial pressure was 2 mm Hg. The left atrial membrane was
resected. Pericardium was used to partition the atria. The
postoperative course was unremarkable.
Case 3. Complete AV Canal and Double Outlet
Right Atrium
History. An 18 month old girl with Down's syndrome
was referred with cyanosis and congestive heart failure presumed to be secondary to complete AV canal. Symptoms
of congestive heart failure were moderately relieved by pulmonary artery banding at 6 months of age. At 18 months
of age, the infant was moderately cyanotic, but in no acute
respiratory distress. The precordiumwas active. The second
heart sound was single. A grade 3/6 holosystolic murmur
was heard at the lower left sternal border. There was no
diastolic murmur. The lungs were clear to auscultation and
the liver was not enlarged.
Laboratory findings. The chest X-ray film showed a
slightly enlarged heart and a small increase in pulmonary
vascular markings. The ECG showed normal sinus rhythm
and a right superior axis with severe right atrial and right
ventricular enlargement. The PR interval was 0.16 ms.
Two-dimensional echocardiography demonstrated situs
solitus, normally related great arteries and a complete AV
canal. In contrast to the usual findings with complete AV
canal, the atrial septum deviated leftward and joined the
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STA RC ET AL.
AV CAN AL AND PULMON ARY VENOUS OBSTRUCTION
JACe Vol. 9. No.4
April 1987:83G-3
Figure 3. Patient 2. Left atrial flow profile in infant
with primum type atrial septal defect and cor triatriatum . A, Subxiphoid atrial long-axis projection
(right) with pulsed Doppler sample volume in the
body of the left atrium (LA) at the ostium of the
membrane. Turbulent monophasic flow (left) reflects restrictive communication between the common pulmonary venous channel (CPY) andthebody
of left atrium. B, Same projection with sample volume placed inthecommon pulmonary venous channel(CPY)(right). Baseline oscillation of flow (left)
contrasts with the profile of acceleration in the left
atrium (LA) across the ostium of the intraatrial
membrane. Other abbreviations as in Figures I
and 2.
lateral wall of the left atrium , above the plane of the AV
groove . The left atrial appendage was proximal to the atrial
septum . The left atrium did not communicate directly with
the left ventricle (Fig. 4).
Cardiac catheterization documented a left to right atrial
shunt and a bidirectional shunt at the ventricular level. Left
ventricular oxygen saturation was 72%. A 60 mm Hg pressure gradient was present across the pulmonary artery band.
The left atrium could not be entered despite multiple attempts to cross the interatrial septum .
Surgical findings. Surgery at 18 months of age showed
a markedly dilated right atrium. The atrial septum inserted
on the lateral wall of the left atrium , above the opening of
the common AV valve . The foramen ovale measured 2 to
3 mm in diameter. The coronary sinus was large, secondary
to persistence of the left superior vena cava. The pulmonary
veins drained normally into the left atrium. The atrial septum
was resected from below the level of the foramen ovale,
and a new interatrial septum was constructed with pericardium establishing continuity between the left atrium and left
ventricle. The remainder of the AV canal was repaired by
double patch technique with a Teflon patch closure of the
interventricular septum.
Cardiac catheterization 6 weeks after surgery showed
mild to moderate mitral insufficiency, mild tricuspid insuf-
Figure 4. Patient 3. Subxiphoid atrial long-axis projection demonstrating a double outlet rightatrium (RA). The interatrial septum
deviates posteriorly and leftward inserting below the left atrial
appendage (LAA). Mitral atresia was excluded by ventricular shortaxis projections displaying a " rectangular shaped " common AY
valve. *Atrial septal defect; other abbreviations as in Figures I
and 2.
JACC
vot. 9. No.4
STARe ET AL.
AV CANA L AND PULMONARY VENOUS OBSTRUCTION
April 19H7:8JO--3
ficiency and angiographic evidence of a trivial left to right
interventricular shunt. Pulmonary artery pressure was 45/16
mm Hg.
Discussion
Pulmonary hypertension is a commonproblem in patients
with complete AV canal and, when associated with high
pulmonary vascular resistance. is a contraindication to surgical repair. AV canal type defects are rarely accompanied
by anatomic pulmonary venous obstruction. However, because this combination could possibly mimic irreversible
pulmonary vascularobstructivedisease, it must be diligently
sought for in any patient with elevated pulmonary artery
pressure.
Cor triatriatum. In the first two cases, cor triatriatum
was the anatomic cause of pulmonary venous obstruction .
Cor triatriatum is rarely combined with AV canal defect
(1,2). Five patients with cor triatriatum and an ostium primum defect (3-6) and two with complete AV canal ( I) have
been previously reported. Symptoms in patients with AV
canal and cor triatriatum are variable and relate to the quantity of pulmonary blood flow and the degree of pulmonary
venous obstruction.
Double outlet right atrium. Our third patient demonstrated an equally rare anomaly, double outlet right atrium.
In this lesion, the interatrial septum joins the lateral wall of
the left atrium above the orifice of the left AV valve and
effectively blocks left atrial blood from entering the left
ventricle. Left atrial blood flows into the right atrium and
then passes into both the right and the left ventricle. Symptoms are variableand are related to the degree of obstruction
of pulmonary venous bloodflow and the associated anatomic
defect. Double outlet right atrium is usually associated with
an ostium primum defect (7-11) but has also been described
in patients with a common AV valve (10-13). an overriding
AV valve (13) and three AV valves (14 y.
Utility of two-dimensional echocardiography. In the
two patients who underwent cardiac catheterization, the diagnosis of anatomic pulmonary venous obstruction was not
apparent on cineangiography. The proper diagnosis was ultimately made by two-dimensional echocardiography. Cor
triatriatum and double outlet right atrium were identified on
two-dimensional echocardiography by the presence of an
atrial membrane or the abnormal course of the atrial septum.
They were distinguishable by the position of the left atrial
appendage. In cor triatriatum, the left atrial appendage was
located distal to the atrial membrane-that is. it was part
of the low pressure left atrium-whereas in double outlet
right atrium, the left atrial appendage was proximal to the
interatrial septum-that is, it was part of the high pressure
left atrium.
Conclusion. Pulmonary vascular obstructive disease is
a contraindication to surgical repair in patients with AV
833
canal. It is essential to identify patients with correctable
anatomic causes of pulmonary venous obstruction and pulmonary hypertension . Causes of pulmonary venous obstruction include mitral stenosis, supravalvular mitral ring or
membrane, double outlet right atrium, cor triatriatum and
pulmonary vein stenosis. Two-dimensional echocardiographyhas been useful in identifying each of these obstructive
lesions except for isolated stenosis within the pulmonary
veins themselves. Although rare, anatomic causes of pulmonary venous obstruction such as cor triatriatum and double outlet right atrium should be considered when elevated
pulmonary vascularresistanceis found in patientswith complete AV canal. These defects can be documented by twodimensional echocardiography and are amenable to surgical
repair.
We thank Rise H. Victor for secretarial assistance.
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