The document discusses the pathologic anatomy of Ebstein's anomaly of the heart based on examination of 15 autopsy specimens. Key findings include: 1) Enlargement of the right atrioventricular junction was consistently found compared to the left side. 2) The anterior leaflet of the tricuspid valve was greatly enlarged and attached abnormally to the ventricular wall by chordae and muscular strands. 3) Massive aneurysmal dilation of the right ventricle was present in two-thirds of hearts examined. Abnormal development of the right atrioventricular junction may be the primary cause leading to malformations of the tricuspid valve apparatus.

1. PEDIATRIC CARDIOLOGY
Pathologic Anatomy of
Ebstein’s Anomaly of the Heart Revisited
KENNETH I?. ANDERSON, MBChB,
FRCPA
J. T. LIE, MD, FACC
Rochester, Minnesota
The typical textbook descripfion of Ebstein’s anomaly of the heart usually
singles out and emphasizes the downward displacement of septal and
posterior leaflets of the tricuspid valve. An anatomic reappraisal of this
uncommon anomaly suggests that other structural abnormalltles of Import
should be equally stressed. Among the 15 well preserved autopsy spec-
imens in this series, enlargement of the rlght atrloventrkular (A-V) junction
and malalignment of the giant and sometimes muscularized anterior leaflet
of the tricuspid valve were consistently found. In addltion, massive an-
eurysmal dilation of the right ventricle was present in almost two thirds
(9 of 15) of the hearts. Our observations rake the posslblllty that abnormal
embryonic development of the right A-V junction may be the primary event
that leads to malformation of the tricuspid valve apparatus.
Ebstein’s anomaly of the tricuspid valve is an uncommon developmental
abnormality that accounts for less than 1 percent of all congenital cardiac
ma1formations.l This curious anomaly has a varied pathologic anatomy
and, according to a large scale international cooperative study,2 a varied
natural history. The variable clinical course is not well explained by the
spectrum of structural abnormalities. Several surgical procedures have
been developed to correct Ebstein’s anomaly, but in general the results
have been relatively disappointing.3-6
The purpose of this reappraisal of Ebstein’s anomaly is to draw at-
tention to certain anatomic features of the anomaly that have received
less emphasis in the past and that may have relevance in the clinical
assessment and surgical correction of this anomaly. A more complete
understanding of the anatomic derangements may also shed new light
on the possible embryogenesis of Ebstein’s anomaly.
Materials and Methods
From the Department of Pathology and Anatomy,
Mayo Clinic and Mayo Foundation. Rochester,
Minnesota. Dr. Anderson is a New Zealand Na-
tional Heart Foundation Fellow in Cardiovascular
Pathology. Manuscript received June 27, 1977;
revised manuscript received October 10, 1977,
accepted October 12, 1977.
Address for reprints: J. T. Lie, MD, Mayo Clinic,
200 First Street Southwest, Rochester, Minnesota
55901.
There were 20 autopsy specimens of classic Ebstein’s anomaly without
transposition of the great arteries in the existing collection of hearts with con-
genital cardiac disease of the Mayo Clinic Department of Pathology and Anat-
omy. Five hearts were excluded because previous pathologic examination made
them unsuitable for detailed anatomic study. The remaining 15 hearts formed
the basis of this report.
Measurements of selected features were made in an attempt to define the
anatomic pattern of structural abnormalities in hearts with Ebstein’s anomaly.
These measurements included the circumference of the right and left atrio-
ventricular (A-V) iunctions, the maximal displacement of the tricuspid valve
leaflets, distkce’fiom the apex to the semilunar valve in the right and left ven-
tricles and distance from the apex to the posterior A-V junction in the right
ventricle.
Histologic evaluations were made of the selected hearts with special reference
to (1) the musculature of the aneurysmally dilated right ventricular “wall,” (2)
the presence or absence of muscle fibers in the anterior leaflet of the tricuspid
valve, and (3) the displaced septal and posterior leaflets to determine whether
April 1978 The American Journal of CARDIOLOGY Volume 41 739

2. EBSTEIN’S ANOMALY-ANDERSON AND LIE
Anterior
Anterior
NORMAL EBSTEIN’S
the leaflet tissue was in continuity with the thickened endo-
cardium of the wall of the inflow (atrial) chamber.
The coronary arterial anatomy was examined in each heart
and particular note was made of the coronary arteries in the
right A-V groove where they might be in danger of being in-
jured by plication procedures for the surgical correction of the
incompetent malformed tricuspid valve.
Results
The A-V junction: In all 15 hearts studied, the ring
where the right atrium joined the right ventricle (right
A-V junction) did not correspond to the ring of at-
tachment of the A-V valve leaflets (tricuspid valve ring).
A consistent finding in Ebstein’s anomaly was en-
largement of the right compared with the left A-V
junction. This enlargement was readily apparent after
comparing the distances around the A-V junction on
either side from the pulmonary valve to the posterior
interventricular septum (Fig. 1). In six normal hearts
FIGURE 1. The ventricles viewed from the back. Left,
in the heart, the distance around the left border of the
heart from the pulmonary valve to the posterior inter-
ventricular septum, at the level of the atrioventricular
groove (A) is approximately the same as the distance
similarly measured around the right border (A’). Right, in
the heart with Ebstein’s anomaly, similar measurements
reveal that the distance around the right border is con-
siderably longer than the distance around the left border.
The added distance (X’) corresponds approximately to
the aneurysmally dilated portion of the right ventricular
wall. LV = left ventricle; PA = pulmonary artery; RV =
right ventricle.
from patients of various ages these measurements were
approximately equal, with the left A-V junction usually
measuring slightly more than the right A-V junction. In
the hearts with Ebstein’s anomaly, the measurement
of the right A-V junction was 1.2 to 2.2 times greater
than the left measurement (Table I). Comparison with
other measurements, such as the apex to aortic valve
distance of the left ventricle, demonstrated that the
inequality of the A-V junction circumferences was-due
to an absolute increase in size of the right A-V junction
rather than a decreased size of the left junction. Among
hearts with a posterior aneurysm, the increased cir-
cumference of the right A-V junction approximately
corresponded to the circumference of the aneurysm (X’
in Fig. 1).
The tricuspid valve: When viewed from the right
atrium, the typical deformity of the tricuspid valve in
all hearts with Ebstein’s anomaly was clearly apparent.
TABLE I
Ebstein’s Anomaly: Atrioventricular Junction Measurements and Associated Anomalies
Case
no. Age Sex
A-V Junction (mm)
Right Left
.
A-V Junction Associated
Ratio (R/L) Anomalies
Right Ventricle Massively Dilated
5
1 day
days
18 mo
2
6 yr
yr
13yr
l5yr
14yr
18yr
12yr
7 days
9
2 days
yr
51
3 yr
yr
M
L
F
F”
M
M
M
M
F
:
M
F
45
::
110 ::
110
100 ::
150’ 80’
180
110 70
90
160 80
Right Ventricle Moderately Dilated
110 60
Right Ventricle Not Dilated
55 :!z
110
60
100
::
100
180
1.5
1.3
1.7
1.7
1.8
1.9’
2.0
1.6
2.9
1.8
1.4
2.2
1.7
1.2
1.8
ASD
PFO
ASD, PS
ASD
ASD
PFO
i&D, LSVC
PFO
PFO
PFO
PFO
ASD, PAtr
PFO.
PFO VSD
l Estimated.
A-V = atrioventricular; LSVC = persistent left superior vena cava; PAtr = pulmonary atresia; PFO = patent foramen ovale; PS = pulmonary
stenosis; R/L = right to left; VSD = ventricular septal defect.
740 April 1978 The American Journal oi CARDIOLOGY Volume 41

3. EBSTEIN’S ANOMALY-ANDERSON AND LIE
The anterior leaflet was attached to the A-V junction
in the correct position with the medial margin of the
attachment contiguous with the anterior border of the
septal leaflet at the membranous septum. As the ob-
server’s eye moved posteriorly, the attachment of the
septal leaflet was seen to be progressively displaced
downward. Rather than being attached normally just
below the A-V junction, it was attached to the ventric-
ular septum, leaving a triangular portion of the ven-
tricular septum exposed to the atrium (Fig. 2). At the
posterior border of the ventricular septum, the septal
leaflet met the posterior leaflet, whose attachment at
this point was also displaced well below the A-V junc-
tion. As the observer’s eye then moved laterally, along
the posterior wall of the ventricle, the attachment of the
posterior leaflet angled upward so that, at the lateral
aspect of the valve, it met the attachment of the anterior
leaflet to the A-V junction. The point of maximal dis-
placement of the tricuspid valve leaflets was where the
septal leaflet met the posterior l.eaflet on the postero-
medial aspect of the right ventricular wall.
The anterior leaflet: Although the anular attach-
ments were similar, the size, shape and construction of
the anterior leaflet in Ebstein’s anomaly bore little re-
semblance to its counterpart in the normal heart (Fig.
3). It was considerably larger and structurally quite
different. From the right margin of its insertion into the
A-V junction, the lateral edge of anterior leaflet passed
downward and medially, approximately parallel and
close to the acute border of the heart. In contrast to the
normal tricuspid valve, in which this edge is entirely
free, in Ebstein’s anomaly it was attached variably to
the ventricular wall. In 10 hearts, attachment was made
by several abnormal papillary muscles and chordae
tendineae, whereas in 5, there was continuous unin-
terrupted muscular attachment of this edge of the
leaflet to the ventricular wall. The markedly abnormal
anterolateral papillary muscle was situated at the lower
extent of the lateral edge. This muscle varied from a
broad-based linear sheet to a more discrete muscle belly,
but it was often difficult to separate visually the papil-
lary muscle proper from the attachment of the lateral
FIGURE 3. The parietal wall of the
right ventricle with the anterior
leaflet of the tricuspid valve (a-TV)
attached, viewed as if looking
toward the right side from within the
cavity of the right ventricle. A, in a
normal heart; B, in a heart with Eb-
stein’s anomaly. The anterior leaflet
in the tatter heart is greatly enlarged
and abnormal in configuration. The
anterolateral papillary muscle (aL-
PM) is poorly formed and the leaflet
is tethered to the posterior right
ventricular wall by abnormal chordal
attachments. PV = pulmonary
valve; RA = right atrium.
FIGURE 2. A view of the right atrium @A), right ventricle (RV) and tri-
cuspid valve looking toward the ventricular septum. The insertion of
the septal leaflet (S-TV) meets the insertion of the anterior leaflet (a-TV)
on the membranous septum (asterisk). Progressing posteriorly, the
insertion of the septal leaflet is displaced into the ventricle, thus ex-
posing a triangular area of ventricular septal wall to the right atrium
(broken lines enclose ventricular septum exposed to the atrium).
edge of the leaflet to the ventricular wall. When this
attachment was uninterrupted, it was often directly
continuous with the papillary muscle.
From the anterolateral papillary muscle, the rather
taut anterior free edge of the leaflet extended in a direct
line to its chordal attachment to the crista supraven-
tricularis (infundibular septum). This free edge was
often slightly thickened. This chordal attachment was
remarkably constant in that it always reached the apex
of the inverted V formed by the junction of the septal
and parietal limbs of the crista. In the heart with Eb-
stein’s anomaly, as in the normal heart, a fibrous ridge
sometimes described as a fusion line may be seen at the
apex of the crista. In the normal heart, the muscle of
Lancisi is attached to the septal limb of the crista some
distance from the cristal apex. In hearts with Ebstein’s
April 1979 The American Journal of CARDIOLOGY Volume 41 741

4. EBSTEIN’S ANOMALY-ANDERSON AND LIE
FIGURE 4, left. The right ventricle (RV) in Ebstein’s anomaly. The anterior leaflet of the tricuspid valve (a-TV) is attached by chordae to the apex of
the inverted V formed by the crista supraventricularis (CS) (arrow). A fibrous raphe sometimes may be visible here in both normal and congenitally
malformed hearts. In the normal heart, the anterior leaflet of the tricuspid valve is attached to the septal bar of the crista some distance from the
cristal apex. This attachment may be chordal or there may be a small papillary muscle (muscle of Lancisi). In Ebstein’s anomaly, the attachment
is always chordal in nature. TSM = trabeculae septomarginalis.
FIGURE 5, right. Close-up view of the anterior leaflet of the tricuspid valve (a-TV) in Ebstein’s anomaly showing the abnormal structure of the leaflet
with fibrous strands incorporated in the leaflet stretching between its attachments to the right A-V junction and the right ventricular (RV) wall. These
strands are in part muscular and in part fibrous. Ant = anterior; Post = posterior; RA = right atrium.
anomaly, the chordal attachment of the anterior leaflet leaflet, the posterior leaflet was thickened, and abnor-
was always directly into the mid line of the crista (Fig. mal chordal attachments tethered it to the ventricular
4). wall.
The structure of the anterior leaflet was also dis-
tinctly abnormal. Instead of being entirely a fibrous
membrane, as in the normal heart, this leaflet was
composed of easily visualized strands, stretching from
the anterolateral papillary muscle to the insertion of the
leaflet into the A-V junction (Fig. 5). These strands
fanned out radially from the anterolateral muscle
toward the attachment of the leaflet at the A-V junction.
In one heart these strands were entirely composed of
muscle, but in other hearts they were partly muscular
and partly fibrous. Thus, muscular continuity appeared
to exist from the anterolateral papillary muscle and the
parietal right ventricular wall to the tricuspid valve ring
at the right A-V junction.
The right ventricle: The right ventricle was divided
into two parts by the abnormal tricuspid valve. These
are usually referred to as the proximal and distal
chambers.
The proximal chamber was continuous with the right
atrium through the now unguarded A-V junction and
was thus a functional part of the right atrium. It has
sometimes been referred to as the atrialized portion of
The septal and posterior (inferior) leaflets: The
attachment of these leaflets in hearts with Ebstein’s
anomaly was displaced below the A-V junction, thus
exposing a triangular area of ventricular wall to the right
atrium. The degree of displacement varied and deter-
mined the relative size of the partitioned parts of the
right ventricle. Greater displacement toward the apex
resulted in a smaller functional right ventricle (distal
chamber) and a larger “atrialized ventricle” (proximal
chamber). The attachment of the septal leaflet was
often displaced down to the trabecula septomarginalis
(moderator band). The mobile part of the leaflet, always
abnormal, varied markedly in size. There were often
recesses in the right ventricle created by excessive
tenting of the mobile part of the septal leaflet. In all
hearts studied, both the septal and the posterior leaflets
had abnormal chordal attachments. Like the septal
FIGURE 6. The external appearance of the posterior surface of a heart
with Ebsteln’s anomaly and a normal-sized (undilated) right ventricle
(RV). A triangular-shaped thin-walled area of aneurysmal dilatation of
the right ventricle is present (arrows). LV = left ventricle: RA = right
atrium.
742 April 1978 The American Journal of CARDIOLGGY Volume 41

5. EBSTEIN’S ANOMALY-ANDERSON AND LIE
the right ventricle. The endocardium of this chamber
was usually thick, fibrous and smooth, although some
poorly formed trabeculae were sometimes present. The
posterior wall corresponded approximately to the
aneurysmally dilated portion of the right ventricle ob-
served most noticeably in those hearts that did not have
generalized right ventricular dilatation (Fig. 6). The wall
of the “aneurysm” was often very thin with sparse
muscle fibers. In two hearts, it was devoid of any muscle
and composed entirely of fibrous tissue.
The distal chamber was, or constituted the functional
unit of, the right ventricle. It communicated with the
proximal chamber by way of the variably sized and
usually incompetent orifice of the tricuspid valve. The
distal chamber was composed of three parts-the in-
fundibulum, the apical part of the ventricle and the
anterolateral recess, which was an appendage-like recess
of the distal chamber situated behind the anterior
leaflet of the tricuspid valve (Fig. 7). The trabecula
septomarginalis often formed a distinctive landmark
in the distal chamber (Fig. 7).
Dilatation of the ventricle: In 9 of the 15 hearts
with Ebstein’s anomaly of the right-sided tricuspid
valve, the right ventricle was markedly dilated and
thin-walled (Fig. 8). Dilatation involved the entire free
wall of the right ventricle, but the posteromedial wall
was thinner than the remainder. This area corresponded
to the area that may be an aneurysmal pouch in the
undilated examples. Of the remaining six hearts, one
showed a moderate degree of dilatation, and five were
either normal or thick-walled with a chamber of normal
size. Generalized dilatation of the ventricle was sub-
jectively assessed and did not appear to be related to the
degree of enlargement of the right A-V ring circumfer-
ence (Table I). No specific feature of the malformation
FIGURE 7. Anterior view of the opened right ventricle in Ebstein’s
anomaly. The anterior leaflet of the tricuspid valve (a-TV) separates
the proximal chamber (PC) from the anterolateral recess of the distal
chamber. The free edge of the anterior leaflet is attached below to the
abnormally formed anterolateral papillary muscle and above to the apex
formed by the junction of the two limbs of the crista supraventricularis
(CS). The displaced septal leaflet (s-TV) is attached toa rather prominent
trabecula septomarginalis (TSM). PV = pulmonary valve.
of the tricuspid valve stood out as being associated with
dilatation.
The coronary arteries: The positions of the coro-
nary ostia and the course of the proximal segments of
the major main coronary arteries were similar to those
in the normal heart. Special attention was directed to
the topography of the coronary arterial anatomy at the
posterior (inferior) surface of the heart because of sur-
gical procedures involving plication of a portion of the
right ventricular wall along the A-V groove. In five
hearts the posterior descending artery was a branch of
the left circumflex coronary artery, and in another five
it was a branch of the right coronary artery. In the latter
group, it seems inevitable that surgical plication of the
posterior wall of the right ventricle would compromise
the arterial circulation to the posterior ventricular wall.
In the remaining five hearts, both the left circumflex
and the right coronary arteries contributed to the de-
scending branches.
Associated cardiac anomalies: All but 1 of the 15
hearts had a shunt at the atria1 level, either an atria1
septal defect or a patent foramen ovale. The only other
cardiac anomalies were one example each of pulmonary
atresia, pulmonary stenosis, ventricular septal defect
and persistent left superior vena cava (Table I).
Discussion
Anatomic Features
In Ebstein’s anomaly of the tricuspid valve consid-
erable variation exists in the pathologic anatomy of the
malformation and in the clinical course of the patients
FIGURE 8. Massive dilatationof the right ventricle in Ebstein’s anomaly.
The right ventricle has been opened anteriorly. Ao = aorta; a-TV =
anterior leaflet of the tricuspid valve; LV = left ventricle; PA = pul-
monary artery: TSM = trabeculae septomarginalis.
April 1979 The American Journal of CARDIOLOGY Volume 41 743

6. EBSTEIN’S ANOMALY-ANDERSON AND LIE
so afflicted. Previously published anatomic studies have
dealt with most features of the anatomy of the malfor-
mation in detail. These features include the displace-
ment of the valve leaflets, the aneurysmally dilated
posterior right ventricular wall7 and its abnormal
structure,s dysplastic changes in the valve leaflets9 the
occasionally observed “plastered” down nature of the
septal leaflet,iOJ1 the architectural abnormality of the
right ventricle11 and the A-V specialized conducting
tissue.11-13 We observed these features in our study, but
we emphasize certain points that have received less
attention in the past.
Enlarged circumference of the right A-V junc-
tion: This was present in all our cases. It should not be
confused with the tricuspid valve ring that in Ebstein’s
anomaly is displaced into the right ventricle. Yater and
Shapiro12 mentioned the enlargement of the right A-V
orifice, and it was exemplified in their paper by a cited
case report of Blackhall-Morison,14 who noted that the
“auriculoventricular orifice admitted the whole hand.”
The degree of enlargement of the right A-V junction
circumference corresponded approximately to the width
of the thinned segment of ventricular myocardium sit-
uated posteromedially (Fig. 1). This thinned segment
of ventricular wall was frequently aneurysmally dilated,
and in two hearts it was a well circumscribed fibrous sac
completely devoid of myocardium.
Generalized dilatation of the entire right ven-
tricle: This abnormality was also previously noted7 and
was a common feature in 64 percent (9 of 15) of the
hearts in our study. It was evident in some of the neo-
natal examples but was more striking in the hearts from
older patients. It was not observed in the oldest patient
in our series (aged 51 years). Dilatation of this ventricle
is probably in part an acquired phenomenon, but there
is no sound hemodynamic explanation for massive di-
latation. Dilatation of this degree has not been observed
in other congenital valve disorders or in acquired disease
of valve incompetence. Gross dilatation of a ventricle
is usually associated with terminal cardiac failure or
abnormalities of the ventricular myocardium such as
congestive cardiomyopathy. We believe it is likely that
some dilatation of the right ventricle is an integral
component of Ebstein’s anomaly, associated with (and
possibly due to) deficiency of the myocardium of the
right ventricle. It is our impression that massive dila-
tation of the right ventricle, when present, may be a
limiting factor in achieving good results with surgical
repair of Ebstein’s anomaly.
Enlarged and abnormal anterior leaflet of tri-
cuspid valve: The anterior leaflet in Ebstein’s anomaly
of the right-sided tricuspid valve is often markedly
enlarged and abnormally structured. This leaflet has
been described as a “trapeze-like” structure or a “sail”
hanging down into the ventricle. The free edge is
stretched between a malformed anterolateral papillary
muscle and an abnormal chordal attachment to the very
apex of the crista supraventricularis. This attachment
is presumably the equivalent of the muscle of Lancisi
that, in the normal heart, is an anchorage for the ante-
rior leaflet of the tricuspid valve and is located at the
septal band of the crista supraventricularis.
Embryologic Considerations
The valve leaflets: The A-V valves are formed rel-
atively late in cardiac embryogenesis, some time after
the A-V connections have been established. The im-
portance of the contribution of ventricular wall myo-
cardium to the actual structure of the primitive valve
leaflets was well known to early workers, and this
subject was reviewed by Odgers in 193’7.15
This has led
to the commonly held belief that the leaflets develop by
a process of undermining or delamination of ventricular
myocardium.16 It has been suggested17 that hemody-
namic factors are important in the development of the
semilunar valves,17 and it is not unreasonable to assume
that hemodynamic factors play a role in the under-
mining process by which the A-V valves develop. A
necessary requirement for correct hemodynamic pat-
terns of flow would be the structural integrity of the A-V
canal, which is normally the narrowest orifice through
which blood passes on its course from the atria to the
ventricles. If an A-V canal was for some reason enlarged
and was no longer the narrowest orifice of ventricular
inflow, then hemodynamic forces in this area could be
expected to be abnormal. If they were abnormal, proper
undermining forces might no longer exist and the valve
leaflets could be expected to form abnormally in both
position and structure.
In our study we consistently found an abnormally
large circumference of the right A-V sulcus in classic
Ebstein’s anomaly. This was found in hearts from pa-
tients of all ages and does not appear to be an acquired
phenomenon. If this enlarged A-V junction was present
at the stage when the valve leaflets were being formed,
it may have been responsible for the anomalous struc-
ture and position of the leaflets. The diameter of max-
imal restriction to blood entering the right ventricle
would no longer be at the A-V junction but would be-
come an area of the right ventricular inflow deeper into
the ventricular chamber.
Enlarged A-V junction: The reason for enlargement
of the right A-V junction is elusive. One can theorize
that the junction may lack proper support during de-
velopment, perhaps because of a deficiency of sulcus
tissue or myoepicardial mantle. However, Ebstein’s
anomaly is almost exclusively a disorder of the tricuspid
valve, and if such a concept of lack of support is valid,
why should Ebstein’s anomaly not occur equally as often
in the mitral valve? 0dgers15 observed several differ-
ences in the developing A-V valves, including angulation
of the lateral aspect at the right A-V orifice, observed
at the 30,mm stage, which was associated with tempo-
rary continuity between A-V sulcus tissue on the epi-
cardial surface and the forming valve leaflet at the en-
docardial surface. This latter point is of interest because
at the equivalent lateral part of the developing mitral
valve, atria1 and ventricular musculature separate the
developing valve leaflet from the epicardially situated
sulcus tissue. If sulcus tissue were deficient on the left
side, the developing mitral valve could still be supported
by left ventricular myocardium; however, if there were
a deficiency of sulcus tissue on the right side, the lateral
aspect of developing tricuspid valve would lack such
744 April 1979 The American Journal of CARDIOLOGY Volume 41

7. EBSTEIN’S ANOMALY-ANDERSON AND LIE
support. Lack of support could result in enlargment of
the orifice followed by abnormal formation of the valve
leaflets.
Conclusion
Apart from the well known downward displacement
of the septal and posterior leaflets of the tricuspid valve,
several other anatomic features are found consistently
enough to warrant their inclusion as integral compo-
nents of the congenital malformation complex of Eb-
1.
2.
3.
4.
5.
6.
stein’s anomaly of the heart. These additional features
include (1) malalignment, enlargement and abnormal
construction of the anterior leaflet of the tricuspid valve;
(2) circumferential expansion of the right A-V junction;
(3) various degrees of aneurysmal dilatation of the entire
right ventricle; and (4) a right to left shunt in the form
of a patent foramen ovale or atria1 septal defect. These
anatomic characteristics should be taken into consid-
eration in designing or carrying out the surgical cor-
rection of Ebstein’s anomaly of the heart.
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