The “wall to wall” heart: Massive cardiothymic silhouette in newborns

The “wall to wall” heart:
Massive cardiothymic silhouette
in newborns
A lthough
Lane F. Donnelly, MD; Karin J. Gelfand; David C. Schwartz, MD; Janet L. Strife, MD
a definitive diagnosis of
most types of congenital heart
disease is made with echocardiography,
chest radiographs often are
the initial imaging study used. Accurate
interpretation of these radiographs facilitates
appropriate work-up and management.
Cardiomegaly in the newborn
may be associated with many types of
congenital heart disease or systemic illness.
However, when a massive “wallto-wall”
cardiothymic silhouette is
found on a chest radiograph, the possible
causes are fewer. Most cases of wallto-wall
heart are related to massive right
atrial enlargement, found in such disorders
as Ebstein’s anomaly of the tricuspid
valve or pulmonary atresia with
intact ventricular septum (PA-IVS). 1-3
Other causes of a massive cardiac silhouette
include pericardial effusions,
atypical large arteriovenous shunts,
hypertrophic cardiomyopathy in infants
of diabetic mothers, and cardiac or
mediastinal masses mimicking massive
cardiomegaly.
There may be some degree of overlap
in the clinical presentation of this
group of neonates. Newborns with
noncardiac causes of massive cardiac
silhouette can present with symptoms
similar to those with congenital heart
disease, which are tachypnea and
wheezing. Cyanosis also may be pres-
Dr. Donnelly is with Duke University
Medical Center in Durham, NC. Ms.
Gelfand, Dr. Schwartz, and Dr. Strife
are with Children’s Hospital Medical
Center in Cincinnati, OH.
APPLIED RADIOLOGY, December 1997
ent, related to cardiac or venous compromise
secondary to compression.
Massive right atrial enlargement
PA-IVS and Ebstein’s anomaly can
result in massive right atrial enlargement.
This produces the largest cardiac
silhouettes seen in neonates. 1-3 When
massive cardiomegaly is associated with
decreased pulmonary flow, Ebstein’s
anomaly or PA-IVS is the most likely
diagnosis. The degree of cardiomegaly
in PA-IVS is related to the competency
of the tricuspid valve. 1 When tricuspid
regurgitation is present, blood flows
“back and forth” from the right ventricle
to the right atrium, and the right atrium
and right ventricle can become massively
enlarged (figure 1). 1 In Ebstein’s
anomaly, there is redundancy and downward
displacement of the leaflets of the
tricuspid valve into the right ventricle,
with adherence of these leaflets to the
right ventricular wall distal to the atrioventricular
annulus. This results in a
tripartite right heart, divided into the
right atrium, an atrialized right ventricle
(portion of the right ventricle located
between the atrioventricular annulus and
the displaced tricuspid valve), and the
right ventricle. 4 A combination of functional
and structural obstruction leads to
massive enlargement of the anatomic
right atrium and atrialized right ventricle
(figure 2). 3,4
Hypertrophic cardiomyopathy in
infants of diabetic mothers
In infants of diabetic mothers, an
increase in myocardial mass may result
in hypertrophic cardiomyopathy and
can be a cause of massive cardiomegaly
(figure 3). 5,6 Congestive heart failure
also can contribute to the degree of cardiomegaly.
5 In these neonates, there is
enlargement of the myocardial cell
resulting in increased myocardial mass.
This myocardial hypertrophy can result
in diminished left ventricular function
(nonobstructive cardiomyopathy), as
well as left ventricular outflow tract
obstruction (obstructive cardiomyopathy).
5
Another cause of cardiomyopathy in
neonates is hypoxic-ischemic cardiomyopathy,
or the so-called “stunned
myocardium.” Hypoxia related to birth
asphyxia can result in temporary
myocardial dysfunction and resultant
cardiac enlargement.
Large arteriovenous shunts
When very large amounts of arteriovenous
shunting occurs, resultant cardiomegaly
can be massive. These
atypically large shunts can be peripheral,
such as arteriovenous malformations
of the liver, brain, or skin (figure
4), or intracardiac, such as a coronary
artery-right heart fistula (figure 5). 7 In
these cases, pulmonary vascularity may
be normal on radiographs because the
increased pulmonary vascular resistance
present in newborns impedes any
increase in pulmonary arterial flow.
Large pericardial effusions
Pericardial effusion in the absence of
hydrops fetalis or sepsis is rare in
neonates. 8 In a previous review of 32
cases of neonatal pericardial effusion,
cardiac tumor was a common cause
23

A C
B
FIGURE 1. Pulmonary atresia with intact
intraventricular septum associated with tricuspid
insufficiency. (A) Chest radiograph
shows massive cardiomegaly with a “wallto-wall
heart.” (B) Right heart with contrast
injection shows massive dilatation of the
right atrium (RA) and right ventricle (RV).
(C) Left heart with contrast injection is normal
sized, with a massively dilated right
atrium and ventricle constituting the bulk of
the cardiac shadow. (D) Autopsy specimen
shows massive enlargement of the right
atrium (arrows).
A
D
FIGURE 2. Ebstein’s anomaly. Chest radiograph
shows massive cardiomegaly with
umbilical venous catheter (arrow) curled
within the dilated right atrium. Pulmonary
vascularity is decreased.
FIGURE 3. Hypertrophic cardiomyopathy in
an infant of a diabetic mother. Radiograph
shows marked cardiomegaly and prominent,
indistinct pulmonary vasculature consistent
with pulmonary venous congestion.
FIGURE 4. Large cavernous hemangioma
of the scalp and upper trunk. (A) Photograph
of an infant with cavernous hemangioma
(arrow). (B) Frontal radiograph
shows marked cardiomegaly and normal
pulmonary vascular markings. The great
arteries and veins are enlarged secondary
to increased flow to the head, widening the
superior mediastinum.
24 APPLIED RADIOLOGY, December 1997
B

A B C
FIGURE 5. Coronary artery to right atrial fistula. (A) Frontal radiograph shows massive cardiomegaly and prominent and indistinct
pulmonary vasculature. (B) Axial T1-weighted MR image shows dilated left coronary artery (arrow) from left coronary artery
to right atrial fistula. (RA= right atrium; P = pulmonary artery; A = descending aorta.) (C) Coronal T1-weighted MR image shows
marked dilatation of the right atrium [RA] constituting the majority of the enlarged cardiac silhouette.
A B C
FIGURE 6. Pericardial effusion secondary to left atrial hemangioendothelioma. (A) Initial radiograph shows enlarged cardiac silhouette
and a hemivertebrae. (B) Gadolinium-enhanced, axial T1-weighted MRI shows a well-defined enhancing mass (arrow)
involving the lateral wall of the left atrium. There is low signal in the pericardial sac consistent with residual air post-pericardialcentesis
(small arrows). (C) After drainage of the pericardial fluid, the cardiac silhouette is normal in size.
A B
A B
APPLIED RADIOLOGY, December 1997
FIGURE 7. Cardiac rhabdomyoma in a newborn
with tuberous sclerosis. (A) Frontal
radiograph shows massive cardiomegaly
mimicking Ebstein’s anomaly. (B) Substernal
longitudinal sonogram demonstrates a
large infiltrative mass (large arrows) arising
from and surrounding the heart (small
arrows).
FIGURE 8. Mediastinal teratoma. (A)
Frontal radiograph shows massive cardiomegaly.
(B) Angiogram shows displacement
of both opacified right and left cardiac
chambers secondary to a large left-sided
mediastinal mass (arrows).
27

A B
A
FIGURE 10. Apparent cardiomegaly secondary
to technical factors. (A) Portable,
frontal anterior-posterior radiograph with lordotic
positioning demonstrates apparent cardiac
enlargement. (B) Lateral chest
radiograph shows normal heart size. The
apparent cardiomegaly seen on the frontal
radiograph is secondary to technical factors.
(38%), with teratoma and cavernous
hemangioma/hemangioma being the
most common types. 8 Other common
causes included thyroid dysfunction
(21%), infection (12%), and diaphragmatic
hernia into the pericardial sac
(16%). 8 When large enough, pericardial
effusions can cause massive enlargement
of the cardiac silhouette (figure 6).
Masses mimicking cardiac chamber
enlargement
Chest masses can sometimes produce
the radiographic “wall-to-wall” appearance
of the heart in newborns, mimicking
diseases such as Ebstein’s anomaly.
We have seen this occur with cardiac
masses such as rhabdomyomas (figure
B
7), mediastinal masses such as teratomas
(figure 8), and congenital
diaphragmatic hernias on early films,
before gas enters the bowel (figure 9).
Children with tuberous sclerosis are predisposed
to developing rhabdomyomas.
Technical factors
Many technical factors can influence
the apparent cardiac size seen on frontal
radiographs. In neonatal intensive care
units, radiographs often are obtained
using the portable anterior-posterior
technique in frontal projection only.
Anterior-posterior projection, lordotic
or rotated positioning, and large focusfilm
distance all may cause the magnification
of apparent cardiac size. 9 Under
FIGURE 9. Congenital diaphragmatic hernia.
(A) Initial radiograph after birth shows
what appears to be massive cardiomegaly.
Note indistinctness of the left hemidiaphragm.
(B) Delayed frontal radiograph
shows aeration of the bowel within the left
hemithorax consistent with a congenital
diaphragmatic hernia. (Image courtesy of
Charles A. Gooding, MD, University of California,
San Francisco, CA.)
these circumstances, a normal heart can
appear to be enlarged (figure 10), especially
if the film is obtained during
expiration. Additionally, a normal thymus
can appear large relative to the
newborn mediastinum and mimic cardiomegaly
on frontal radiographs. In
cases where cardiac enlargement is in
question on frontal radiographs, lateral
radiographs are helpful in determining
whether cardiac enlargement is true or
artifactual. AR
REFERENCES
1. Kanjuh VI, Stevenson JE, Amplatz K, et al:
Congenitally unguarded tricuspid orifice with coexistent
pulmonary atresia. Circulation 30:911-
915, 1964.
2. Anderson KR, Lie JT: Pathologic anatomy of
Ebstein’s anomaly of the heart revisited. Am J Cardiol
41:739-745, 1978.
3. Strife JL, Bisset GS III: Cardiovascular system.
In: Kirks DR (ed), Practical Pediatric Imaging, pp
417-513. Boston, Little, Brown and Company,
1991.
4. Bialostozky D, Horwitz S, Espino-Vela J:
Ebstein’s malformation of the tricuspid valve: A
review of 65 cases. Am J Cardiol 29:826-836,
1972.
5. Dunn V, Nixon GW, Jaffe RB, Condon VR:
Infants of diabetic mothers: Radiographic manifestations.
AJR 137:123-128, 1981.
6. Way GL, Wolfe RR, Eshaghpour E, et al: The
natural history of hypertrophic cardiomyopathy in
infants of diabetic mothers. J Pediatrics 95:1020-
1025, 1979.
7. Jaffe RB, Glancy DL, Epstein SE, et al: Coronary
arterial-right heart fistulae: Long-term observations
in seven patients. Circulation 47:133-143,
1973.
8. Cartagena AM, Levin TL, Issenberg H, Goldman
HS: Pericardial effusion and cardiac hemangioma
in the neonate. Pediatr Radiol 23:384-385,
1993.
9. Amplatz K, Moller JH: Radiology of Congenital
Heart Disease, pp 55-113. St. Louis, Mosby-Year
Book, Inc., 1993.
28 APPLIED RADIOLOGY, December 1997