Download Ventricular Septal Defect

HISTORY
18-year-old man.
CHIEF COMPLAINT: Heart murmur present since early infancy.
PRESENT ILLNESS: Although normal at birth, a heart murmur was heard at
the six week check-up and has persisted since that time.
asymptomatic with normal growth and development.
Question:
He has been
What category of heart disease is suggested by this history?
25-1
Answer:
A significant murmur beginning in infancy is almost certainly due
to a congenital heart defect. The absence of symptoms suggests that the
murmur represents either mild ventricular outflow obstruction or a shunt lesion.
The absence of a murmur at birth suggests the latter, as a shunt murmur does
not occur until pulmonary vascular resistance falls following birth.
The fact that the murmur was heard as early as six weeks after birth is against
the diagnosis of atrial septal defect. This relates to the fact that the systolic
murmur in atrial septal defect is soft and difficult to hear in a young infant.
Proceed
25-2
PHYSICAL SIGNS
a. GENERAL APPEARANCE - Normal 18-year-old man.
b. VENOUS PULSE - The CVP is estimated to be 3 cm of H2O.
UPPER RIGHT STERNAL EDGE
JUGULAR VENOUS PULSE
Question:
How do you interpret the venous pulse?
25-3
Answer:
The venous pulse is normal in mean pressure and wave form.
c. ARTERIAL PULSE - (BP = 100/60 mm Hg)
S1
S2
UPPER RIGHT
STERNAL EDGE
CAROTID
ECG
Question:
How do you interpret the arterial pulse?
25-4
Answer:
The arterial pulse is normal. If a moderate or large shunt at the
great vessel level were present, one would expect a wide pulse pressure and a
bounding arterial pulse.
PHONO
UPPER RIGHT
STERNAL EDGE
APEXCARDIOGRAM
Question:
How do you interpret the apexcardiogram?
25-5
Answer:
The apexcardiogram is normal.
e. CARDIAC AUSCULTATION
PHONO
LOWER LEFT
STERNAL
EDGE
S1
S2
S1
S2
ECG
0.2
sec
Question:
How do you interpret these acoustic events?
25-6
Answer:
There is a holosystolic murmur at the lower left sternal edge. It is
less intense at the apex. These findings are consistent with a ventricular septal
defect. There is neither a third heart sound nor a flow rumble at the apex
indicating that the shunt is small. A large flow ventricular septal defect would
result in significantly increased mitral valve flow producing an apical diastolic
flow rumble.
e. CARDIAC AUSCULTATION (continued)
ECG
1
2
1
A2 P2
1
A2 P2
0.1
sec
2L
EXPIRATION
Question:
INSPIRATION
How do you interpret the acoustic events at the upper left
sternal edge?
25-7
Answer:
There is normal inspiratory splitting of the second heart sound.
The short, early crescendo-decrescendo murmur is due primarily to the
turbulence of flow across the pulmonary outflow tract during maximum ejection
(“innocent” murmur). Radiation of the murmur from the lower left sternal edge
may also contribute.
f. PULMONARY AUSCULTATION
Question:
How do you interpret the acoustic events in the pulmonary lung
fields?
Proceed
25-8
Answer:
In all lung fields, there are normal vesicular breath sounds.
ELECTROCARDIOGRAM
I
II
III
aVR
aVL
aVF
V1
V2
V3
V4
V5
V6
NORMAL STANDARD
Question:
How do you interpret this ECG?
25-9
Answer:
The ECG is within normal limits.
CHEST X RAYS
PA
LATERAL
Questions:
1. How do you interpret the chest X rays?
2. Based on the history, physical examination, ECG and chest X rays, what is
your diagnosis and plan to further evaluate this patient?
25-10
Answers:
1. The chest X rays are normal. The absence of increased pulmonary arterial
vascularity and the normal heart size are consistent with a small shunt.
2. Based on the history, physical examination, ECG, and chest X rays, the
patient has a small ventricular septal defect not requiring surgical closure.
An echocardiogram provides additional diagnostic information. The patient’s
study follows.
25-11
LABORATORY- ECHOCARDIOGRAM
RV
LA
LV
RV
Ao
VSD
=
=
=
=
=
Left Atrium
Left Ventricle
Right Ventricle
Aorta
Ventricular
Septal Defect
LV
VSD
Ao
LA
TWO-DIMENSIONAL PARASTERNAL LONG AXIS
Question:
How do you interpret this echocardiogram?
Proceed
25-12
Answer:
The echocardiogram demonstrates a structure which moves
anteriorly in systole (arrows) and appears to be attached to the ventricular
septum. This structure represents a so-called aneurysm of the ventricular
septum. Its formation is one mechanism by which a membranous ventricular
septal defect may close. In some patients, an early systolic sound, best heard
at the lower left sternal edge with the patient sitting, may indicate the presence
of such a septal aneurysm.
While cardiac catheterization is not indicated in this patient a study which
demonstrates the septal defect and associated aneurysm follows.
Proceed
25-13
LABORATORY(continued)
LEFT VENTRICULAR ANGIOGRAM
Left Anterior Oblique
The arrows clearly outline a
pedunculated aneurysm of
the membranous ventricular
septum.
Proceed for associated
hemodynamic data.
25-14
LABORATORY(continued) - CATHETERIZATION DATA
SITE
PRESSURE
(mm Hg)
OXYGEN
SATURATION(%)
Superior Vena Cava
Mean = 3
68
Right Atrium
Mean = 3
68
25/3
73
23/9 Mean = 13
75
Mean = 5
98
100/5
98
Right Ventricle
Main Pulmonary Artery
Left Atrium
Left Ventricle
Aorta
Question:
98/70 Mean = 80
98
How do you interpret these data?
25-15
Answer:
There is a significant increase in oxygen saturation at the right
ventricular level (normal =<3%) indicating a left-to-right shunt. The slight further
increase in saturation in the pulmonary artery reflects better mixing of shunt
flow with systemic venous return rather than an additional shunt at the great
vessel level. The left-to-right shunt calculates at 23% of pulmonary blood flow,
that is, the ratio of pulmonary to systemic flow (Qp/Qs) is 1.3 to 1. Right heart
pressures are normal as expected.
Question:
How would you treat this patient?
25-16
Answer:
Surgery is not indicated for this small ventricular septal defect.
The only significant risk is infective endocarditis. The patient was instructed in
proper antibiotic prophylaxis at the time of dental manipulation (including
cleaning and filling) and surgery of the gastrointestinal or genitourinary tract.
Proceed for Summary
25-17
SUMMARY
Ventricular septal defects may be isolated or occur in association with other
cardiac abnormalities. In infants, they are the most commonly diagnosed
congenital cardiac defect. Bicuspid, non-stenotic aortic valves are more
common, but frequently go unrecognized because of the subtle nature of the
physical signs.
Ventricular septal defects are classified according to their location. The
membranous defect lies beneath the crista supraventricularis in proximity to the
tricuspid valve. Viewed from the left ventricle, these defects lie beneath the
right aortic cusp.
Proceed
25-18
SUMMARY (continued)
Muscular defects are commonly small and located in the mid portion of the
septum. Small defects usually close spontaneously. In infancy, muscular
defects can be quite large, producing severe symptoms.
The least common type is the supracristal ventricular septal defect which lies
above the crista supraventricularis, immediately below the pulmonary valve, so
that the valve seems to “override” the septum. Viewed from the left ventricle,
the defect lies close to the aortic valve cusps. These defects may be large and
rarely undergo spontaneous closure. Because of proximity to the aortic valve,
aortic regurgitation is more likely to occur than in other types. This defect is
more common in infants of Asian descent.
Proceed
25-19
SUMMARY (continued)
The majority of small ventricular septal defects close spontaneously during the
first two years of life, most during the first six months. They may be obliterated
by growth along the edge of the defect, redundant tricuspid leaflet tissue, or
septal aneurysm formation. Of those that persist, few require surgical
treatment.
Obstructive pulmonary arteriolar disease does not occur due to small
ventricular defects. Infective endocarditis is the only risk in those patients in
whom the defect remains patent. If endocarditis occurs, the site is usually on
the right ventricular wall or on the tricuspid valve. Aortic regurgitation
occasionally is associated with a small membranous VSD.
The typical pathology of a membranous infracristal defect follows.
Proceed
25-20
PATHOLOGY
R
VSD
P
M
S
VSD
RIGHT VENTRICULAR VIEW
S = septal leaflet of tricuspid valve
Arrow = papillary muscle of the conus
LEFT VENTRICULAR VIEW
R = right aortic cusp
P = posterior aortic cusp
M = mitral valve anterior leaflet
In this specimen the defect is not as small as in the patient presented and is
unassociated with a septal aneurysm.
Proceed for Case Review
25-21
To Review This Case of a
Small Ventricular Septal Defect:
The HISTORY is typical, including the appearance of a murmur at six
weeks of age without symptoms.
PHYSICAL SIGNS:
a. The GENERAL APPEARANCE is normal.
b. The JUGULAR VENOUS PULSE is normal in mean pressure and
wave form.
c. The CAROTID ARTERIAL PULSE is normal.
d. PRECORDIAL MOVEMENT is normal.
Proceed
25-22
e. CARDIAC AUSCULTATION reveals normal first and second heart
sounds. There is a loud holosystolic murmur at the lower left sternal edge
which radiates well to the apex. The soft early crescendo-decrescendo
murmur at the upper left sternal edge is due primarily to flow across the
pulmonary outflow tract.
f. PULMONARY AUSCULTATION reveals normal vesicular breath sounds
in all lung fields.
The ELECTROCARDIOGRAM and
normal.
CHEST X RAYS
are
LABORATORY STUDIES
include the echocardiogram which
demonstrates a ventricular septal aneurysm. Although invasive study is
unnecessary, catheterization data from a typical case showed the ventricular
septal defect, aneurysm and oxygen step-up at the ventricular level.
TREATMENT consists of infective endocarditis prophylaxis.
25-23