Transcript Congenital Heart Disease

Congenital Heart Disease
Lab Module
December 17, 2009
Instructions
• From what you have learned in the lecture,
try to diagnose the congenital cardiac
anomaly that is being illustrated in each
photograph
• Try to orient the specimen or photo first,
then identify landmarks, then look for the
defect
• Good luck!
Septal defect
in
membranous
part
1
ANS: Perimembranous VSD
• Type that occurs in about 90% of VSD
cases. (Robbins)
• Involves region of membranous septum
(as opposed to infundibular VSD, which
lies below the pulmonary valve or within
the muscular septum) (Robbins)
• Located in the left ventricle outflow tract
beneath the aortic valve (emedicine)
• Defects may extend into adjacent portions
of the ventricular septum. (emedicine)
• Perimembranous VSD is caused by failure
of the endocardial cushions, the
conotruncal ridges, and the muscular
septum to fuse at a single point in space.
(emedicine)
• Closes spontaneously in most cases.
(emedicine)
ANS: Coarctation of the Aorta
branches of the aorta
Constriction
2
This image is of an aortic arch; the aorta has been opened up.
Coarctation of the Aorta
• Structural anomaly
• Constriction or narrowing of the aorta
• Two classic forms:
– With PDA (often symptomatic in early
childhood)
– Without PDA (usually asymptomatic children)
3
ANS: Coarctation of the Aorta
constriction
3
4
ANS: Mitral Stenosis
2 cusps
4
Chordae
tendinae not
seen because
view is from
above (kunwari
nasa atrium ka
tumitingin sa
ventricle through
the valve). Pero
in mitral stenosis,
dapat fused and
thickened na sila.
ANS: Mitral Stenosis
• Failure of mitral valve to open completely,
thereby impeding forward flow to the left
ventricle (Robbins)
• Cardinal anatomic changes:
– Leaflet thickening
– Commisural fusion and shortening
– Thickening and fusion of the tendinous chords
• Fibrous bridging and calcification usually
result in “fish mouth” or “buttonhole”
stenoses.
• NOTE: The trick daw when presented with a picture of a
valve is to first orient the picture in relation to the
ventricles and/or atria. Then count the cusps. Mitral
valve – bicuspid (2 cusps); Tricuspid – tricuspid duh
haha (3 cusps). Semilunar valves look alike – 3 fibrous
leaflets.
7
ANS: Persistent Truncus
Arteriosus
Single great
artery
receiving
blood from
both
ventricles
Very small branch,
connected to single
great artery via
collateral arteries
(one with a star)
Valve
ANS: Persistent Truncus
Arteriorsus
• Arises from a developmental failure of
separation of the embryologic truncus
arteriosus into the aorta and the
pulmonary artery.
• Results in a single great artery that
receives blood from both ventricles and
gives rise to the systemic, pulmonary, and
coronary circulations.
• Because there is an associated VSD and
mixing of blood from the right and left
ventricles, PTA produces systemic
cyanosis as well as an increased
pulmonary blood flow, with the danger of
irreversible pulmonary hypertension.
8
ANS: Tetralogy of Fallot
• There are four cardinal features of TOF:
1. VSD
2. Obstruction of the right ventricular
outflow tract (subpulmonary stenosis)
3. An aorta that overrides the VSD.
4. Right ventricular hypertrophy.
 Morphology of the heart
 Often enlarged and may be “boot-shaped as a
result of the marked right ventricular
hypertrophy, particularly the apical region
• The VSD is usually large.
• The aortic valve forms the superior border
of the VSD, thereby overriding the defect
and both ventricular chambers
• Obstruction to the RV flow is most often
due to narrowing of the infundibulum
(subpulmonic stenosis) but can be
accompanied by pulmonary valvular
stenosis
• If the subpulmonary stenosis is mild, the
abnormality resembles an isolated VSD,
and the shunt may be left-to-right, without
cyanosis (so-called pink tetralogy)
• As the obstruction increases in severity,
there is a commensurately greater
resistance to right ventricular outflow. As
right-sided pressures approach or exceed
left-sided pressures, right-to-left shunting
develops, producing cyanosis (Classic
TOF).
• The subpulmonary stenosis, however,
protects the pulmonary vasculature from
pressure overload, and right ventricular
failure is rare because the right ventricle is
decompressed by the shunting of blood
into the left ventricle and the aorta.
9
ANS: Anomalous Pulmonary
Venous Connection
• Results when the pulmonary veins fail to
directly join the left atrium.
• Results embryologically when the common
pulmonary vein fails to develop or
becomes atretic.
• Either patent foramen ovale or and ASD is
always present, allowing pulmonary
venous blood to enter the left atrium.
• Cyanosis may be present as a result of
mixing of well-oxygenated and poorly
oxygenated blood at the site of the
anomalous pulmonary venous connection
and the large right-to left shunting through
ASD.
• Consequences:
– Volume and pressure hypertrophy and
dilatation of the right side of the heart
– Dilatation of the pulmonary trunk .
– Left atrium is hypoplastic
– Left ventricle is usually normal in size
ANS: Patent Ductus Arteriosus
• Also called Persistent Ductus Arteriosus.
• Results when the ductus arteriosus, an
essential fetal structure that normally
spontaneously closes, remains open after
birth.
• Occurs as an isolated anomaly 90% of the
time. The remainder are most often
associated with VSD, coarctation of the
aorta, or pulmonary or aortic valve
stenosis
• Produces a characteristic continuous harsh
murmur, described as “machinery-like.”
• Usually asymptomatic at birth.
• There is no cyanosis, but eventually the
additional volume and pressure overload
produce obstructive changes in small
pulmonary arteries, leading to reversal of
flow and its associated consequences.
• Preservation of ductal patency (by
administering prostaglandin E) assumes
great importance in survival of infants with
various congenital malformations that
obstruct the pulmonary or systemic outflow
tracts (e.g.patients with aortic valve
atresia).
10
ANS: Persistent Truncus
Arteriorsus
• Arises from a developmental failure of
separation of the embryologic truncus
arteriosus into the aorta and the
pulmonary artery.
• Results in a single great artery that
receives blood from booth ventricles and
gives rise to the systemic, pulmonary, and
coronary circulations.
•
• Because there is an associated VSD and
mixing of blood from the right and left
ventricles, PTA produces systemic canosis
as well as an increased pulmonary blood
flow, with the danger or irreversible
pulmonary hypertension.
BONUS
ANS: Atrioventricular Septal
Defect
• Results from the embryologic failure of the
superior and inferior endocardial cushions
of the AV canal to fuse adequately.
• The consequence is incomplete closure of
the AV septum and malformation of the
tricuspid and mitral valves.
• Two Most Common Forms:
– Partial AVSD (consisting of a primum ASD
and a cleft anterior mitral leaflet, causing
mitral insufficiency)
– Complete AVSD (consisting of a large
combined AV septal defect and a large
common AV valve—essentially a hole in the
center of the heart.
• In complete form, all four cardiac chambers
freely communicate, inducing volume
hypertrophy of each.
• More than 1/3 of all patients with a complete
AVSD have Down Syndrome. Surgical repair
is possible.