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Infant heart dissection in a forensic context: babies are not just small
adults
Matshes Evan W., Trevenen Cynthia
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Acad Forensic Pathol. 2011 Sep; 1(2): 156-165
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INVITED REVIEW
Infant Heart Dissection in a Forensic Context: Babies Are
Not Just Small Adults
Evan W. Matshes MD FRCPC, Cynthia Trevenen MD FRCPC
Evan Matshes, MD, FRCPC is a
Clinical Associate Professor of
Pathology with the University of
Calgary and Calgary Laboratory
Services in Calgary, Alberta.
Author affiliations: Department of
Pathology and Laboratory Medicine
Calgary Laboratory Services and
University of Calgary - Division of
Pediatric Pathology (CT).
Contact Dr. Matshes at:
[email protected].
Acad Forensic Pathol
2011 1 (1): 156-165
ABSTRACT: Medical examiners who investigate infant deaths are required to consider a
large number of natural and non-natural causes due to the broad differential diagnosis of unexpected infant death. Among the myriad of causes are those related to disorders in structure
and function of the cardiovascular system. Adult hearts are routinely and efficiently evaluated by medical examiners because of the large anatomic structures and limited spectrum
of commonly encountered diseases. Infant deaths are comparatively rare. Although infant
hearts may be evaluated with similar efficiency, the pathologist must first have a detailed
knowledge of developmental cardiovascular anatomy and of the subtleties of a broad spectrum of infantile cardiovascular pathology. Furthermore, the pathologist must be aware of
additional details to be observed and documented in infant cardiac studies, and of the dissection techniques that facilitate acquisition of that data. Rote dissection of an infant heart as if it
were an adult heart may lead to overlooked malformations and diseases that may have been
the underlying cause of death. This brief review paper covers the fundamentals of pediatric
cardiovascular anatomy and dissection techniques as they apply to the practice of pediatric
forensic pathology.
KEYWORDS: Forensic pathology, Autopsy, Cardiovascular diseases, Sudden unexpected infant death
https://doi.org/10.23907/2011.021
Page 156 • Volume 1 Issue 2
© 2017
Academic Forensic Pathology International
INTRODUCTION
Experience in North American medical examiner
systems shows that the vast majority of infants
who die suddenly are ‘apparently normal’ prior
to their deaths. It is the rare infant who presents
to the medical examiner with antemortem signs
and symptoms suggestive of primary cardiac disease such as congestive heart failure, arrhythmia
or thromboembolic events. For the past four or
more decades forensic pathologists routinely diagnosed sudden infant death syndrome (SIDS),
and over those years SIDS gained popularity not
just as a descriptive label for infants dying suddenly without known cause, but eventually as an
actual disease (1). The predictable inexplicability
of such infant deaths lead some forensic pathologists to perform fast, superficial and inadequate
autopsies, sometimes without studies as basic
as histology. In some jurisdictions, the autopsy
culture views SIDS-type autopsies as nearly per-
functory, a fact illustrated by the comment “baby
autopsies should be the fastest autopsies you do,
there’s never anything to see”. When viewed as a
chore and performed with haste, infant autopsies
may routinely be unrevealing.
The pediatric heart, when viewed simply as a
miniaturized adult heart, is easy to examine.
In such a situation the prosector is able to ‘fly
through’ the dissection, making note of the lack
of atherosclerotic coronary artery disease, the
lack of cardiomegaly associated with hypertensive heart disease, and then conclude their
assessment with little or no cardiac histology.
Yet, when studied in detail by cardiac pathologists over a five year period, one third of natural
child deaths were found to be cardiac in origin,
70 percent of which had macro- or microscopic
pathology detectable at autopsy (2). If cases such
as these had been treated superficially and the
diagnoses missed, the causes of death may have
been labeled “undetermined” or “SIDS”. Families, society and the legal system can derive no
benefit from such errors.
FUNDAMENTALS OF THE RELATED ANATOMY
Textbooks, treatises, and scholarly articles
abound to guide clinicians, surgeons and pathologists in the fine details of cardiac anatomy (3-5),
pediatric cardiology (6, 7), and cardiac dysmorphology (8-10). The average anatomic pathology
trainee receives limited education about cardiac
anatomy and pathology as it relates to infants,
and formal training in pediatric autopsy techniques is not included in the ACGME Program
Requirements for Graduate Medical Education
in Forensic Pathology (11). As a result, some forensic pathology fellows will transition into their
staff forensic pathologist roles without having
achieved competency with pediatric heart dissections. For those pathologists who find themselves
in such a position, the above referenced materials
and the following brief discourse are offered as
an introduction to this highly complex area.
Van Praagh pioneered the segmental approach
to cardiac analysis in the 1960’s by proposing
a straight-forward framework within which the
anatomy of any heart could be described (12).
In this system, each heart is composed only of
three parts or segments – the atria, the ventricles,
and the arterial trunks. The atria and ventricles
in turn are either of right or left configuration,
and the arterial trunks are aortic or pulmonic in
distribution. None of the segments are directly
connected to one another, rather, they are joined
by connecting segments. Those connecting segments are the atrioventricular junctions and the
infundibulum. The ventriculoarterial junctions
are assessed based on their relationships to the
ventricles, the relationships between the trunks,
the related valve anatomy, and the configuration
of the infundibulum.
Sequential segmental analysis proceeds with determination of the atrial arrangement, an assessment of the atrioventricular junctions (including the atrioventricular valves) and ventricular
morphology, evaluation of the ventriculoarterial
junctions and their corresponding connections.
Anatomic landmarks fundamental to the assessment of the described segments and connectors
are summarized in Table 1.
APPROACH TO THE INFANT HEART DISSECTION
The thorough assessment of an infant’s cardiovascular system is not limited to the heart itself.
The infant heart dissection should be preceded
by review of all available case information and
data derived from all components of a complete
autopsy.
Case history
Historical features suggestive of primary cardiac disease are uncommon in a forensic context.
However, careful (often physician medical examiner-driven) interviews of parents may elicit
signs suggestive of congestive heart failure. To
that end, in addition to the routinely conducted
thorough interview of parents whose infants have
just died, directed questioning should target features suggestive of tachycardia, perioral or generalized cyanosis (especially when feeding or
crying), tachypnea, grunting, nasal flaring, low
energy, poor growth, pallor, sweating, cool extremities and poor feeding.
Matshes & Trevenen • Page 157
Although the heart is considered in isolation for
the majority of this and subsequent discussions,
the relationship of the heart to the other organs
of the trunk must first be considered. Specifically, the heart is normally located in the left chest
(levocardia), and its apex points in a leftward
fashion. This differs from dextrocardia in which
a heart is in the right chest, and the apex points
Sequential segmental analysis
INFANT HEART DISSECTION
Infant autopsies are not just small adult autopsies. The smaller size of the decedent should not
indicate to the pathologist that there is less to examine. On the contrary, when one considers the
volume of anatomy to be assessed, and the broad
differential diagnoses that must be entertained
both at the autopsy table and later at the microscope, those actively engaged in the provision of
quality pediatric forensic pathology know that a
valuable end-product requires dedication. To that
end, the evaluation of the fresh or fixed infant
heart must be done with great care and consideration of the whole case history, evaluation of
the infants’ entire body, and the appearance of
the heart, lungs and major vasculature. A forensic
pathologist who recognizes that a heart is grossly
abnormal, but who opts for the meaningless descriptor of “congenital heart disease” rather than
an anatomically correct diagnosis is not producing a good end-product. Without determining the
true nature of the malformation, the relationship
of the cardiac pathology to sudden death cannot
be scientifically assessed, nor can the risk of recurrence in subsequent children be conveyed to
surviving family members.
toward the right; such an arrangement is seen in
situs inversus totalis.
INVITED REVIEW
Table 1: Critical anatomic landmarks of morphologically normal atria, ventricles and great vessels
Region
Normal features
Right atrium
Appendage is triangular and has a broad-base; pectinate muscles (and crista terminalis) extend
within the atrial body; superior and inferior vena cava and coronary sinus enter into atrium*; rim
of the fossa ovalis;
Thin atrial appendage with pectinate muscles confined to the appendage; no crista terminalis;
smooth-walled interior; valve flap of the fossa ovalis; pulmonary veins**.
Is the most anterior heart chamber; tricuspid valve annulus and chordal attachments to the septum***; coarse trabeculations including the moderator band, parietal band and septal band; welldeveloped infundibulum that separates the fibrous skeleton between the tricuspid and pulmonic
valves; usually supplied by one coronary artery that runs along the atrioventricular groove.
Mitral valve annulus with no chordal attachments to the septum; mitral valve leaflets attach to the
free wall via papillary muscles; fine trabeculations; no separation in the fibrous skeleton of the
mitral and aortic valves; usually supplied by two coronary arteries – one in the anterior interventricular groove, and the other in the atrioventricular sulcus.
Three semilunar cusp leaflets with rightward-facing (right coronary), leftward facing (left
coronary) and non-facing (non-coronary) sinuses of Valsava; coronary arteries arise below the
sinotubular junctions; arch gives rise to the brachiocephalic trunk, left common carotid artery and
left subclavian artery, and then continues on as the descending aorta.
Three semilunar cusp leaflets with rightward-facing, leftward facing and non-facing sinuses of
Valsava; right and left pulmonary arteries into the pulmonary hila.
Left atrium
Right ventricle
Left ventricle
Aorta
Pulmonic trunk
* If systemic venous return is abnormal, those vessels may not actually connect to the right ventricle.
In such a situation, they cannot be used to determine normalcy of right atrial anatomy. An intact coronary
sinus and inferior vena caval origin are often considered the most reliable markers of normal atrial
anatomy. As bilateral superior vena cava are not rare, the superior vena cava is not as useful in this regard.
** The pattern of pulmonary venous return to the left atrium is highly variable. Most commonly,
blood flows from the lungs to the left atrium through four ostia, two per lung (26).
*** Rather than focusing on valve leaflet numbers per se, the tricuspid valve is said to be found in a morphologically right
ventricle, and a mitral valve is found in a morphologically left ventricle.
Radiography
All infants undergoing forensic autopsy first undergo full-body radiography (ideally multiple
individual plates rather than a babygram). Although these radiographs are most commonly
used to identify osseous pathology, radiographs
of the chest should also be used for triage-type
assessment of cardiothoracic pathology. Cautions, of course include that cardiomegaly may
erroneously appear on infant films as: (1) radiographs are most often obtained in the anteroposterior plane, (2) the films are non-inspirational,
(3) normal infant diaphragmatic level is higher
than in adults, (4) the heart is normally disproportionately larger than in adults, and (5) the
cardiothymic silhouette imparts a disproportionately large appearance to the heart. At the same
time, the lungs should be evaluated for features
suggestive of pneumonia and pulmonary edema.
Page 158 • Volume 1 Issue 2
In situ assessment
All components of the infant evisceration should
be carried out by a forensic pathologist, or by
a skilled and knowledgeable forensic autopsy
technician who is under the direct supervision of
the pathologist. Following removal of the chest
plate, a thorough in situ inspection of all internal
organs and tissues (e.g., the diaphragm) should
take place. The author (Matshes) follows detailed
internal evaluation with directed anatomic block
dissections rather than en bloc removal of all internal organs. For example, the liver, pancreas,
stomach and duodenum may be removed as one
unit. There is no advantage to removing all internal organs as a single block if a detailed in situ
inspection has taken place, and if the pathologist
performs the evisceration. In an autopsy context
all that connects the chest and abdominal organs
is the aorta, inferior vena cava and the esophagus – all of which can be effectively evaluated
in other ways.
The thymus must be carefully reflected away
from the pericardium so as to allow for the identification of the brachiocephalic vein. Absence
of the brachiocephalic vein is the most common first indication that the superior vena cava
is duplicated. The pericardium is opened and
removed exposing the heart and great vessels.
This wide exposure allows for detailed assessment of the external morphology of the heart. It
is at this stage that the pathologist makes his/her
first major cardiac triage decision – (1) examine
the heart in situ in its fresh state, (2) examine the
heart fresh ex situ in its fresh state, or (3) formalin fix the heart, lungs and great vessels for more
detailed studies and/or consultation.
Table 2: Perfusion fixation of the infant heart and lung block*
1.
2.
4.
5.
6.
7.
*
INFANT HEART DISSECTION
3.
Tie or clamp off the superior vena cava as far from the right atrium as possible.
Insert the canula into the inferior vena cava (IVC) from the undersurface of the diaphragm and
loosely tie the IVC to hold the canula in place.
Tie or clamp off the thoracic aorta immediately distal to the ligamentum arteriosum. Tie off
each of the main branches off the aortic arch.
Gently introduce formalin through the canula until both lungs have inflated. Tie off the IVC
and remove the canula.
Insert the canula into the trachea, gently tie the trachea to hold the canula (and formalin) in
place and gently introduce formalin to further expand the lungs.
Foramlin may have backflowed into the left side of the heart causing it to perfuse. If not, make
a small incision in the left atrial appendage and insert the canula into the left atrial cavity;
gently tie or clamp the canula in place and introduce formalin. Remove the canula and clamp
the incision.
Submerge the whole block into a bucket of formalin. Do not allow the specimen to sink as the
subsequent deformities defeat the purpose of perfusion inflation.
Necessary equipment list: 60 milliliter syringe, formalin (10% NBF is okay; 20% NBF is ideal), a small bore plastic or rubber
canula (easily obtained at a medical supply company; they are also often discarded by radiology departments and can
be obtained there); copious string or small hemostats. Although the above materials allow for efficient (and rapid)
perfusion of the block, the ideal method is to deliver formalin slowly through two simultaneous ports (venous and arterial)
through catheters attached to a low boy filled with formalin.
To fix or not to fix?
The decision whether or not a pathologist retains
the heart, lungs and great vessels for future studies may be guided by jurisdiction-specific tissue
retention policies. From a purely medical standpoint, the author (Matshes) advocates for evaluation of hearts in the fresh state when careful in
situ evaluation suggests that the likelihood of
cardiac dysmorphology is low, and in particular,
when the infant has died of some other obvious
cause (e.g. blunt trauma). In such cases, the heart
may be carefully dissected the along the pathway
of blood flow as it remains attached to the lungs
and great vessels whether in situ or ex situ. All
of the critical anatomy can be assessed in this
state (including pulmonary arterial outflow and
venous return) including assessment of valve and
blood vessel diameters (achieved with the use
of inexpensive, calibrated cervical dilators; Image 1). Once the dissection is complete, the heart
is removed from the heart-lung-vessel block,
weighed, and sampled for histologic evaluation.
Image 1: This apparently normal infant heart was dissected in situ. Opening the
heart along the pathway of blood flow allows for assessment of all major anatomic landmarks. The technique also allows the pathologist to assess internal
valve diameters. This is easily accomplished with a set of inexpensive calibrated
cervical dilators. In this example, the pulmonic valve diameter is assessed.
Matshes & Trevenen • Page 159
If the heart is obviously abnormal (including
being subjectively enlarged), or the likelihood
of cardiac pathology is high, the authors advocate for en bloc removal of the heart, lungs and
great vessels, followed by formalin perfusion of
the heart and lungs, prior to dissection. Formalin
perfusion is easily carried out by the pathologist
or forensic autopsy technicians. A brief guide to
perfusion fixation is included in Table 2.
INVITED REVIEW
Image 2A: In this example the heart-lung-vessel block is
evaluated following perfusion-fixation. Perfusion of the heart
and vessels allows for detailed assessments of internal
anatomy; it also facilitates preparation of excellent lung histology slides as artifactual atelectasis is generally prevented.
Image 3: At autopsy this heart was noted to have a slightly
‘bulky’ left ventricle and was subsequently perfusion-fixed
with formalin. The heart was then cut in a left ventricular
outflow tract view which did not demonstrate outflow tract
pathology.
Ex situ assessment
Image 2B: Following removal of the descending aorta, trachea, esophagus and soft tissues, the pulmonary arteriovenous return can be assessed in detailed from the posterior
aspect of the block.
Similar to in situ dissection, ex situ dissection
should permit a highly detailed evaluation of
the heart. All of the anatomic landmarks listed
in Table 1 should be assessed. Externally, careful attention should be paid to the assessment
of pulmonary arterial outflow and venous return
(Images 2A through 2C). Only after the pulmonary vasculature has been assessed should the
pathologist consider removing the heart from the
heart-lung block.
Page 160 • Volume 1 Issue 2
Plane of dissection
Image 2C: Lateral retraction of the lungs allows for assessment of the pulmonary arterial vasculature as it passes distally from the heart into the pulmonary parenchyma.
There is no ‘right’ way to dissect a heart. However, some techniques will more adequately illustrate the pathology of interest in a given case.
In many cases, simply following the pathway of
blood will adequately demonstrate the internal
cardiac anatomy. The four-chamber view nicely demonstrates the relationship of each of the
chambers to one another, and is also useful for
the assessment of chamber size. The left ventricular outflow tract view is an excellent way to assess hearts with an enlarged left ventricular mass
as it facilitates assessment of the interventricu-
INFANT HEART DISSECTION
Image 4A: At autopsy this heart had an unremarkable
external morphology. The apical half of the heart was removed, and the remainder of the heart was dissected along
the pathway of blood flow in continuity with the lungs and
great vessels. The apical half of the heart was then serially
sectioned.
Image 5: This formalin-perfused heart was removed from
the heart-lung-vessel block following detailed external assessment. In this Image the right atrium has been opened
along the coronary sulcus exposing a 5 millimeter diameter
patent foramen ovale.
nearly 6%) following formalin fixation (14). Numerous references exist for assessing infant heart
weight. Normal heart weights for males (Table 3)
and females (Table 4) are included.
Image 4B: These contiguous sections of heart represent
serial sections from the heart demonstrated in Image 3. Regardless of the plane of section selected for evaluation, the
myocardium should be thoroughly assessed for pathology.
lar septum and any impingement it may have on
flow from the left ventricle (Image 3). An excellent review of these techniques is available in the
cardiac pathology textbook by Virmani (13).
Regardless of the plane of dissection selected,
the pathologist should also consider transversely
sectioning the myocardium to more thoroughly
assess for myocardial pathology (Image 4A and
4B). However, more thorough dissections may
also limit future review of the heart – a factor
that should be considered with each knife stroke.
Heart weight
Photographing cardiac malformations is notoriously difficult, owing to the three-dimensional nature of most anomalies. Various probes,
clamps, string and other devices can be used to
help provide exposure to the various compartments of the heart (Image 5). A helpful (and
steady) assistant can make the photography of
such specimens far less tedious.
THE USE OF HISTOLOGY
All infant forensic autopsies require histology
Infants undergoing forensic autopsy should have
thorough histologic studies as a matter of routine.
It is difficult to define sampling adequacy in this
context, with the answer lying somewhere between ‘none’ and ‘heart submitted in toto’. Given
the smaller size of the infant heart, it is necessary
to submit multiple sections to increase the myocardial surface area for examination. This will
Matshes & Trevenen • Page 161
The weight of an infant’s heart is an important
marker of normalcy. Pathologists should know
that heart weight decreases slightly (on average
Photography
INVITED REVIEW
Table 3: Heart Weights and Measurements of Male Infants
Age,
Months
Number
of Cases
1
45
2
3
4
41
32
33
Body
Length,
cm.
Heart
Weight,
g.
51.4 †
23
5.9
2.6
38
S.D. *
7
1.5
0.7
S.E. *
1.3
0.2
M. *
M.
6
7
8
39
21
23
10
11
Page 162 • Volume 1 Issue 2
12
16
15
16
21
5
4
4
3
0.1
0.9
0.5
0.5
0.4
6.0
2.9
42
25
34
23
1.0
6
4
5
3
S.E.
1.2
0.3
0.2
1.0
0.7
0.9
0.6
30
6.4
2.5
44
27
36
26
57.7
S.D.
7
1.7
1.0
5
4
5
4
S.E.
1.4
0.4
0.2
0.9
0.7
1.0
0.8
31
6.5
2.3
47
27
38
26
7
1.3
0.7
5
4
4
4
1.4
0.3
0.1
1.1
0.9
0.9
0.7
35
6.8
2.6
48
29
41
27
S.D.
5
1.9
0.8
5
4
5
4
S.E.
0.9
0.4
0.2
0.9
0.7
1.0
0.8
M.
60.4
M.
M.
62.0
40
7.4
2.6
50
31
42
28
S.D.
8
1.7
0.9
6
5
4
3
S.E.
1.4
0.3
0.2
1.0
0.8
0.7
0.6
43
7.6
2.8
50
31
42
29
M.
64.2
66.7
S.D.
8
1.9
1.1
6
5
4
4
S.E.
1.9
0.5
0.3
1.4
1.2
1.1
0.9
44
7.6
2.7
52
32
44
32
8
1.8
1.0
8
4
6
3
1.8
0.4
0.2
1.9
0.9
1.3
0.8
45
7.4
2.4
54
32
45
30
S.D.
7
1.6
0.6
7
4
4
3
S.E.
1.7
0.4
0.2
1.9
1.0
1.1
0.9
M.
68.2
S.E.
19
33
1.5
S.D.
9
23
7
S.E.
32
Aortic
Valve,
mm.
27
S.D.
5
Mitral
Valve,
mm.
S.D.
M.
54.0
Wall
Wall of Tricuspid Pulmonary
of Left
Right
Valve,
Valve,
Ventricle, Ventricle,
mm.
mm.
mm.
mm.
M.
M.
69.4
46
7.5
2.6
54
34
45
33
S.D.
6
1.5
0.7
6
5
4
4
S.E.
1.6
0.5
0.2
1.8
1.6
1.3
1.2
48
7.3
2.5
55
33
46
32
M.
69.7
70.5
S.D.
7
1.4
0.4
4
3
3
3
S.E.
1.9
0.5
0.1
1.1
0.9
0.9
0.9
50
7.9
2.8
55
35
47
33
S.D.
6
1.6
0.8
4
4
3
2
S.E.
1.7
0.5
0.2
1.2
1.2
1.0
0.6
M.
73.8
* M. indicates the mean; S.D., the standard deviation; S.E., the standard error of the mean.
† S.D. and S.E. for body length given in Schulz, Giordano, and Schulz.
Reproduced from Archives of Pathology, 1962, Volume 74, Pages 464-71. Copyright© 1962 American Medical Association. All rights reserved.
Table 4: Heart Weights and Measurements of Female Infants
Number
of Cases
1
24
Body
Length,
(cm)
Heart
Weight,
(g)
51.9 †
21
5.3
2.7
38
5
1.0
0.7
1.2
0.3
26
6.3
S.D.
6
S.E.
1.1
M. *
S.D. *
S.E. *
2
3
4
5
33
34
22
18
M.
M.
54.0
7
8
9
23
23
10
11
12
14
12
21
5
4
4
2
0.2
1.3
0.9
0.9
0.6
2.8
40
25
34
22
1.5
0.8
5
3
5
3
0.3
0.2
1.0
0.6
1.0
0.6
6.0
2.6
42
26
36
25
1.1
5
3
4
3
S.E.
0.8
0.2
0.2
0.9
0.6
0.7
0.5
30
6.6
2.5
45
28
38
26
59.0
S.D.
6
1.1
0.8
5
3
5
4
S.E.
1.3
0.3
0.2
1.2
0.7
1.3
0.8
36
7.0
2.6
49
28
39
28
5
1.6
0.8
6
3
4
4
1.3
0.5
0.2
1.6
0.9
1.1
1.1
37
7.1
2.5
48
29
40
28
S.D.
7
1.3
0.7
5
4
4
3
S.E.
1.6
0.3
0.2
0.9
0.9
1.1
0.6
M.
62.2
M.
M.
63.0
40
7.1
2.7
50
28
40
28
S.D.
9
1.7
1.1
7
5
4
4
S.E.
2.2
0.4
0.3
1.6
1.2
1.0
0.9
41
7.2
2.5
50
29
41
29
M.
65.4
66.5
S.D.
7
1.4
0.7
5
4
7
4
S.E.
1.5
0.3
0.2
1.0
0.8
1.5
0.8
41
7.0
2.6
51
30
42
30
5
1.2
0.7
6
5
5
4
1.6
0.4
0.2
2.1
1.6
1.6
1.4
43
7.2
2.5
53
31
45
30
S.D.
7
2.4
0.7
3
3
5
3
S.E.
2.4
0.8
0.2
1.1
1.1
1.8
1.0
M.
68.3
S.E.
11
31
1.2
S.D.
10
23
4
S.E.
22
Aortic
Valve,
(mm)
28
S.D.
6
Mitral
Valve,
(mm)
S.D.
M.
57.0
Wall
Wall of Tricuspid Pulmonary
of Left
Right
Valve,
Valve,
Ventricle, Ventricle,
(mm)
(mm)
(mm)
(mm)
M.
M.
67.5
44
7.4
2.6
53
32
46
32
S.D.
8
1.4
0.7
5
3
3
4
S.E.
2.0
0.5
0.2
1.4
1.0
1.0
1.1
49
7.8
2.7
54
32
46
33
M.
70.5
71.5
S.D.
6
2.4
0.5
4
4
4
5
S.E.
1.8
0.6
0.2
1.4
1.4
1.4
1.5
Reproduced from Archives of Pathology, 1962, Volume 74, Pages 464-71. Copyright© 1962 American Medical Association. All rights reserved.
Matshes & Trevenen • Page 163
* M. indicates the mean; S.D., the standard deviation; S.E., the standard error of the mean.
† S.D. and S.E. for body length given in Schulz, Giordano, and Schulz.
INFANT HEART DISSECTION
Age,
Months
INVITED REVIEW
facilitate identification of subtle changes such
as inflammation, intracellular accumulations,
ischemia, and disorders in myofiber arrangement
and size. Selection of histologic sections should
be guided by the macroscopic findings. In cases
with no apparent findings, a number of histologic
sections are recommended (Table 5). When sections are submitted in the transverse plane, the
right and left ventricles and the interventricular
septum are easily sampled in three blocks (apex,
mid-heart and basal levels). Nearly the entire
interatrial septum (with adjacent atria) and the
upper part of the interventricular septum can be
sampled in three separate blocks, allowing not
only for assessment of the atrial septal musculature and soft tissues, but also the atrioventricular node and its approaches. Rasten-Almqvist et
al. reported that in more than half of their infant
myocarditis cases, inflammation was isolated to
the upper part of the interventricular septum (15).
benefit is controversial (21). At this time immunohistochemistry is likely best utilized in the
assessment of very rare cardiac tumors and disorders such as histiocytoid cardiomyopathy (22,
23).
Some infant hearts require special stains
ADJUNCT MOLECULAR STUDIES
Delineation of the underlying nature of some histopathologic anomalies will occasionally require
the use of special stains. Most commonly, this
includes Masson or Gomori trichrome, an elastic stain such as Elastic-Van-Gieson or the pentachrome Movat stain and periodic acid-Schiff
(PAS).
A comprehensive discussion of molecular autopsy techniques is beyond the scope of this paper. Several death investigation systems utilize
molecular methods of analysis in cases of unexpected death, including those of infants. The
benefits of such techniques include the identification of genetic aberrations that may suggest
the decedent had an underlying disorder of heart
rate and/or rhythm such as that which might occur in the channelopathies (24, 25). In the context
of an otherwise negative death investigation and
autopsy, such a discovery will lead some medical examiners to ascribe the cause of death to the
disorder implicated by the mutation. Forensic pathologists should be familiar with the types and
specimens required by their molecular pathology
laboratory, and necessary transport mediums.
Examples of frequently collected fresh tissue include whole blood, serum, fresh heart and spleen.
Rare infant hearts require electron microscopy
Intracellular accumulations may be best assessed
by electron microscopy. In medical examiner settings such evaluations will be exceedingly rare.
Forensic pathologists who encounter apparently
idiopathic enlargement of an infant heart, or features suggestive of infiltrative disease should
consider contacting a pathologist at their local
children’s hospital for collection and processing of specimens, and interpretation of electron
micrographs. Although the performance of electronic microscopy is considered highly unusual
by the vast majority of forensic pathologists, rare
cases will see benefit from its use – family members may receive critical information about the
nature of their infant’s underlying illness and its
relevance (if any) to first degree family members
including future siblings.
Page 164 • Volume 1 Issue 2
Is there a role for immunohistochemistry in
infant heart assessment?
Immunohistochemical assessment of the infant
heart has been primarily directed at attempts to
improve diagnostic sensitivity and specificity of
myocarditis. Although reports exist that espouse
the benefits of such investigations (16-20), the
Table 5: Routine histologic sampling of the
infant heart in cases of sudden and apparently
unexplained death
Site
Level
Right ventricle
Left ventricle
Interventricular
septum
Interatrial septum
Apex, mid-heart, base
Apex, mid-heart, base
Mid-heart, base
Any obvious
abnormality
Atrioventricular nodal region
and its approaches including the
upper interventricular septum
All levels
CONCLUSION
Infant hearts might be small, but detail-oriented
dissection is laborious. Forensic pathologists who
investigate infant deaths must be knowledgeable
of normal and abnormal cardiac morphology, as
well as the myriad of cardiac diseases and anomalies that may be discovered at autopsy. Dedicated evaluation of the infant heart (in the context of
proper death investigation with thorough autopsy
and appropriate ancillary studies) will facilitate
proper cause and manner of death certification
in these difficult cases. Furthermore, the answers
derived from such investigations will help families in profound ways.
ACKNOWLEDGEMENTS
REFERENCES
1.) Nashelsky M, Pinckard JK. The Death of SIDS. Acad For
Path. 2011 Jul;1(1):92-8.
2)Tavora F, Li L, Burke A. Sudden coronary death in
children. Cardiovasc Pathol. 2010 Nov-Dec;
19(6):336-9.
3) Gray H, Standring S, Ellis H, Berkovitz BKB. Gray’s
anatomy : the anatomical basis of clinical practice. 39th
ed. Edinburgh ; New York: Elsevier Churchill
Livingstone; 2005.
4)Anderson RH, Wilcox BR. Understanding cardiac
anatomy: the prerequisite for optimal cardiac surgery.
Ann Thorac Surg. 1995 Jun;59(6):1366-75.
5) Anderson RH, Brown NA. The anatomy of the heart
revisited. Anat Rec. 1996 Sep;246(1):1-7.
6) Moss AJ, Allen HD. Moss and Adams’ heart disease in
infants, children, and adolescents : including the fetus
and young adult. 7th ed. Philadelphia: Wolters Kluwer
Health/Lippincott Williams & Wilkins; 2008.
7) Keane J, Lock J, Fyler D. Nadas’ Pediatric Cardiology.
2 ed. Philadelphia, PA: Elsevier; 2007.
8) Van Praagh R, Takao A. Etiology and morphogenesis of
congenital heart disease. Mount Kisco, N.Y.: Futura
Pub. Co.; 1980.
9) Clark EB, Nakazawa M, Takao A. Etiology and
morphogenesis of congenital heart disease : twenty
years of progress in genetics and developmental
biology. Armonk, NY: Futura Pub. Co.; 2000.
10) Perloff JK. The clinical recognition of congenital heart
disease. 5th ed. Philadelphia: W.B. Saunders; 2003.
11) ACGME Program Requirements for Graduate Medical
Education in Forensic Pathology. ACGME; 2004 [cited
6/10/2011]; Available from: http://www.acgme.org/acwebsite/
downloads/rrc_progreq/310forensicpath07012004.pdf.
12) Van Praagh R. The segmental approach to diagnosis in
congenital heart disease. . In: Bergsma D, editor. Birth
defects original article series, VIII, No 5 The National
Foundation - March of Dimes. Baltimore: Williams and
Wilkins; 1972. p. 4-23.
INFANT HEART DISSECTION
Forensic Autopsy Technicians Mrs. Wendy Sitko, Miss Samantha Foster, Mr. Gene Wickens
and Mr. Donald Cavadini are sincerely appreciated for their assistance and patience with all aspects of Dr. Matshes’ forensic autopsy practice,
but in particular, with pediatric forensic studies.
Forensic Photographer Mr. Matthew Spidell took
the in situ photograph (Image 1). Dr. Leslie Hamilton reviewed the manuscript and provided helpful suggestions for improvement.
13) Virmani R, Burke A, Farb A, Atkinson J. Cardio vascular Pathology. 2 ed. Philadelphia: WB Saunders
Company; 2001.
14) Ludwig J. Handbook of autopsy practice. 3rd ed.
Totowa, N.J.: Humana Press; 2002.
15) Rasten-Almqvist P, Eksborg S, Rajs J. Myocarditis and
sudden infant death syndrome. APMIS. 2002
Jun;110(6):469-80.
16) Dettmeyer R, Baasner A, Haag C, et al. Immunohistochemical and molecular-pathological diagnosis
of myocarditis in cases of suspected sudden infant death
syndrome (SIDS)--a multicenter study. Leg Med
(Tokyo). 2009 Apr;11 Suppl 1:S124-7.
17) Madea B. Sudden death, especially in infancy—
improvement of diagnoses by biochemistry,
immunohistochemistry and molecular pathology. Leg
Med (Tokyo). 2009 Apr;11 Suppl 1:S36-42.
18) Dettmeyer R, Schlamann M, Madea B. Immuno histochemical techniques improve the diagnosis
of myocarditis in cases of suspected sudden infant death
syndrome (SIDS). Forensic Sci Int. 1999 Nov 1;
105(2):83-94.
19) Calabrese F, Thiene G. Myocarditis and inflammatory
cardiomyopathy: microbiological and molecular
biological aspects. Cardiovasc Res. 2003 Oct 15;
60(1):11-25.
20) Dettmeyer R, Baasner A, Schlamann M, et al.
Coxsackie B3 myocarditis in 4 cases of suspected sudden
infant death syndrome: diagnosis by immuno histochemical and molecular-pathologic investigations.
Pathol Res Pract. 2002;198(10):689-96.
21) Krous HF, Ferandos C, Masoumi H, et al. Myocardial
inflammation, cellular death, and viral detection
in sudden infant death caused by SIDS, suffocation, or
myocarditis. Pediatr Res. 2009 Jul;66(1):17-21.
22) Edston E, Perskvist N. Histiocytoid cardiomyopathy
and ventricular non-compaction in a case of sudden
death in a female infant. Int J Legal Med. 2009 Jan;
123(1):47-53.
23) Ruszkiewicz AR, Vernon-Roberts E. Sudden death
in an infant due to histiocytoid cardiomyopathy. A
light-microscopic, ultrastructural, and immunohisto chemical study. Am J Forensic Med Pathol. 1995 Mar;
16(1):74-80.
24) Tester DJ, Ackerman MJ. The role of molecular autopsy
in unexplained sudden cardiac death. Curr Opin
Cardiol. 2006 May;21(3):166-72.
25) Basso C, Carturan E, Pilichou K, et al. Sudden cardiac
death with normal heart: molecular autopsy. Cardiovasc
Pathol. 2010 Nov-Dec;19(6):321-5.
26) Marom EM, Herndon JE, Kim YH, McAdams HP.
Variations in pulmonary venous drainage to the left
atrium: implications for radiofrequency ablation.
Radiology. 2004 Mar;230(3):824-9.
Matshes & Trevenen • Page 165