seminar ASD

1. WELCOME
TO
SEMINAR
Presented by
Dr. Farhana Ferdousi
Resident (Phase A)
Department Of Neonatology

2. ATRIAL SEPTAL DEFECT
(ASD)

3. ATRIAL SEPTAL DEFECT (ASD)
 ASD is an opening in the
atrial septum permitting the
shunting of blood between
two atria.
 ASD can occur in any
portion of the atrial septum,
depending on which
emdryonic septal structure
has failed to develop.
 Less commonly, the atrial
septum may be nearly
absent, with the creation of
functional single atrium.

4. EPIDEMIOLOGY
 ASD (ostium secundum defect) occurs as
an isolated anomaly in 6% to 10% of all
congenital heart defects.
 It is more common in females than in males
(male/female ratio of 1:2).
 About 30% to 50% of children with
congenital heart defects have an ASD as
part of the cardiac defect.

5. EPIDEMIOLOGY
 The majority of cases of ASD are sporadic.
 Autosomal dominant inheritance does occur as
part of the Holt-Oram syndrome (hypoplastic or
absent radii, 1st-degree heart block, ASD) or in
families with secundum ASD and heart block.
 Down syndrome is associated with both primum
& secundum ASD while Noonan syndrome most
commonly with secundum ASD with PVS.

6. Formation
of the
Inter atrial septum

7.  It begins at the end of 4th week by development of 2
septa.
 Septum primum : a thin crescent-shaped
membrane grows from the roof of common atrium
into the fusing endocardial cushions dividing
common primitive atrium into right & left halves.
 Osteum primum is formed to pass oxygenated
blood from right to left atrium. It disappears as
septum primum fuses with the endocardial
cushions,(A1-C1).
 Before closure of foramen primum , perforations
appear in central part of septum primium coalesce
to form Osteum Secundum (C1-D1)

9. Septum secundum :
A crescentic muscular membrane grows and
descends from roof of atrium during 5th week. It
overlaps foramen secondum in septum primum .
 The gap between the lower free border of
S.secundum and the upper edge of S.primum
form ‘’foramen ovale’’.
 Cranial part of S.primum disappears and
remaining part of S.primum which attached to
endocardial cushions forms flaplike valve of the
foramen ovale.

12.  In the fetus (before birth) : The pressure is higher in right
atrium than in the left and highly oxygenated blood flows
directly from right atrium to left atrium through open foramen
ovale.
 After birth : When the circulation of the lungs begins & the
blood pressure in left atrium rises ,the upper edge of septum
primum is pressed against the upper limb of septum
secundum. This will close the foramen ovale ,forming a
complete partition between the 2 atria.
 The fossa ovalis an oval depression in the right atrium at
the level of inter atrial septum . It is a remnant of a thin
fibrous sheet that covered the foramen ovale.

14. Normally, oxygen-poor
(blue) blood returns to the
right atrium from the body,
travels to the right ventricle,
then is pumped into the
lungs where it receives
oxygen. Oxygen-rich (red)
blood returns to the left
atrium from the lungs,
passes into the left
ventricle, and then is
pumped out to the body
through the aorta.

15. An atrial septal defect
allows oxygen-rich (red)
blood to pass from the
left atrium, through the
opening in the septum,
and then mix with
oxygen-poor (blue)
blood in the right atrium.

16. Types of ASDs:
 Ostium secundum defect→70% of ASDs.
 Ostum primum defect→20% of ASDs.
 Sinus venosus defect.→4% -11%%of ASDs.
 Coronary sinus septal defect→ < 1% of ASDs .
Patent foramen ovale does not ordinally produce
intracardiac shunts & is not considered as ASD.

17. TYPES OF ASD

18. OSTIUM SECUNDUM DEFECT
 Ostium secundum defect is the most common type
of ASD, accounting for 50% to 70% of all ASDs.
 An ostium secundum defect in the region of the
fossa ovalis is the most common form.
 Secundum ASDs may be single or multiple
(fenestrated atrial septum), openings ≥2 cm are
common in symptomatic older children.
 Large defects may extend inferiorly toward the IVC
& ostium of the coronary sinus, superiorly toward
the SVC, or posteriorly.

19. OSTIUM SECUNDUM DEFECT
Associations:
o Partial anomalous pulmonary venous return
o Pulmonary valvular stenosis
o VSD
o Pulmonary artery branch stenosis
o Persistent left superior vena cava
o Mitral valve prolapse and insufficiency
o Holt-Oram syndrome

20. OSTIUM PRIMUM DEFECT
 Ostium primum
defects occur in about
20% of all ASDs.
 Located in the lower
portion of the atrial
septum and overlies
the mitral and
tricuspid valves.

21. OSTIUM PRIMUM DEFECT :
 An ostium primum atrial septal defect (ASD) is
located in the most anterior and inferior aspect of
the atrial septum.
 Cleft of anterior leaflet of the mitral valve is noticed.
 Tricuspid valve is usually functionally normal.
 Most commonly associated with Down syndrome
(trisomy 21).

22. SINUS VENOSUS DEFECT
 Sinus venosus defect occurs in about 10% of all
ASDs.
 It is most commonly located at the entry of the SVC
into the RA (superior vena caval type) and rarely at
the entry of the IVC into the RA (inferior vena caval
type). The former is very commonly associated with
anomalous drainage of the right upper pulmonary
vein (into the RA), and the latter is often associated
with anomalous drainage of the right lung into the
IVC (“scimitar syndrome”)

23. CORONARY SINUS ASD
 There is a defect in the roof of the coronary
sinus.
 The LA blood shunts through the defect and
the coronary sinus ostium into the RA,
which produces clinical pictures similar to
those in other types of ASD.

24. PATHOPHYSIOLOGY:
The degree of left-to-right shunting is dependent
on
 The size of the defect,
 Relative compliance of the wall of right and left
ventricles,
 Vascular resistance in the pulmonary and
systemic circulations.

25. PATHOPHYSIOLOGY CONT…
 In large defects, shunt of oxygenated blood
flows from the left to the right atrium & is
added to the venous return of the right
atrium and is pumped by the right ventricle
to the lungs.
 With large defects, the ratio of pulmonary to
systemic blood flow (Qp : Qs) is usually
between 2 : 1 and 4 : 1.

26. PATHOPHYSIOLOGY CONT…
 In early life ventricular muscular wall is thick
and less compliant, thus limiting the left-to-
right shunt.
 As the infant becomes older and pulmonary
vascular resistance drops, the right
ventricular wall becomes thinner and so
left-to-right shunt increases and results in
enlargement of the right atrium and ventricle
and dilatation of the pulmonary artery.
 The left atrium may also be enlarged, but
the left ventricle and aorta are normal in
size.

27. PATHOPHYSIOLOGY CONT…
 Pulmonary vascular resistance remains low
throughout childhood, although it may begin
to increase in adulthood and may eventually
result in reversal of the shunt and clinical
cyanosis.

29. CLINICAL MANIFISTATION:
 Most often is asymptomatic.
 Subtle failure to thrive , exercise intolerance .
 Frequent respiratory infections
Physical Findings:
 Usually discovered incidentally during general
physical examination.
 May reveal a mild left precordial bulge
 An RV systolic lift may be palpable at the left
sternal border.
 Loud S1.
 Sometimes a pulmonic ejection click can be
heard.
 Fixed and widely split S2 .

30. CLINICAL MANIFISTATION CONT …
Ejection systolic murmur at middle and upper
left sternal border, produced by the increased
flow across the right ventricular outflow tract into
the pulmonary artery, usually grade 3/6,medium
pitched, without harsh qualities & seldom with a
thrill.
Mid diastolic rumbling murmur at the lower left
sternal border produced by the increased
volume of blood flow across the tricuspid valve.

31. INVESTIGATIONS
ECG
Chest X-RAY
Echocardiography
Sometimes cardiac catheterization

32. CXR FINDINGS
1.Cardiomegaly with
enlargement of the
RA and right
ventricle may be
present.
2. A prominent
pulmonary artery (PA)
segment and
increased pulmonary
vascular markings are
seen when the shunt
is significant.

33. ATRIAL SEPTAL
DEFECT WITH
INCREASED
PULMONARY
VASCULARITY

34. ELECTROCARDIOGRAM
 In most instances the rhythm is normal sinus.
Low atrial rhythm (negative p wave)may point to
a sinus venosus defect.
 Peaked tall p wave as can be seen in right atrial
dilatation while right ventricular volume overload
may manifest as rsR′ pattern (incomplete right
bundle branch block) in leads V1 to V3. This is
usually seen with right axis deviation between 95
to 170°. If left axis deviaion is found then
primum ASD should be highly suspected.

35. RIGHT BUNDLE BRANCH BLOCK

36. ECHOCARDIOGRAPHY
 A two-dimensional echo
study is diagnostic. It
shows the position as
well as the size of the
defect. With a
characteristic brightening
of the echo image seen
at the edge of the defect
caused by increased
reflectivity of ultrasound
at the tissue blood
interface (T-artifact).

37. Pulsed Doppler examination reveals a
characteristic flow pattern with the maximum left-
to-right shunt occurring in diastole. Color flow
mapping enhances the evaluation of the
hemodynamic status of the ASD.

38. Transesophageal
echocardiography (TEE)
• may be used as an
alternative for older
children and
adolescents,
especially in those
who are overweight.
• used to detect a sinus
venosus ASD.
• is a monitoring
adjunct for operative
and per-cutaneous
closure of ASD.

39. DIAGNOSIS CONT…
Cardiac Catheterization:
 Confirmation of the defect
 Measuring of the shunt ratio and PVP & resistance.
 Note : In the case of classical features of ASD on
physical examination , CXR ,and ECHO which
Identify isolated secundum ASD , there is no need
for the cardiac cath before surgery.

40. MANAGEMENT
Medical
1. Exercise restriction is unnecessary.
2.Prophylaxis for infective endocarditis is
indicated in patients with primum ASD.
3. In infants with CHF, medical
management is recommended because
of its high success rate and the possibility
of spontaneous closure of the defect.

41. ASD CLOSURE
 Surgery or transcatheter device closure.
 Indications :
Large defects >8mm.
All symptomatic patients.
Asymptomatic patients with QP:QS
ratio of >2:1 or
those with right ventricular enlargement
 Timing : Elective closure after one year and
before entry of school.

42. NONSURGICAL CLOSURE
 Several closure devices that can be
delivered through cardiac catheters have
been known to be safe and efficacious for
ASD closure.
 These devices are applicable only to
secundum ASD with an adequate septal rim.

43. NONSURGICAL CLOSURE
 Devices available for clinical use:
A. Amplatzer septal occlude
B. Gore Helix septal occlude
C. CardioSEAL device
D. BioSTAR device

44. INDICATIONS OF DEVICE CLOSURE
 A secundum ASD, measuring 5 mm or more
in diameter (but less than 32 mm)
 A significant left-to-right shunt with clinical
evidence of right ventricular volume overload
(i.e., Qp/Qs ratio of 1.5:1 or greater or RV
enlargement).
 There must be enough rim (4 mm) of septal
tissue around the defect for appropriate
placement of the device.

45. ADVANTAGES OF NONSURGICAL
CLOSURE
 Complete avoidance of cardiopulmonary
bypass
 Avoidance of pain and residual thoracotomy
scars
 A less than 24-hour hospital stay, and rapid
recovery.
 Incidence of serious complications (e.g.,
device erosion) is 0.1%.

46. POST-DEVICE CLOSURE FOLLOW-
UP
 The patients are administered aspirin 5
mg/kg/day for 6 months.
 Post procedure echo studies check for a
residual atrial shunt and unobstructed flow
of pulmonary veins, coronary sinus, and
venae cavae and proper function of the
mitral and tricuspid valves.

47. SURGICAL CLOSURE
Indications and Timing
 A left-to-right shunt with a pulmonary-to-
systemic blood flow ratio ( p/ s) of ≥1.5:1 only if
device closure is not considered appropriate.
 Primum septal defects,sinus venosus &
coronary sinus defects,& defects with
associated anomalous pulmonary venous
drainage.
 Secundum atrial defects >38mm in diameter or
with insufficient rim, <5mm.

48. SURGICAL CLOSURE

49. SURGICAL CLOSURE
Complications:
 Cerebrovascular accident and
 Postoperative arrhythmias

50. POSTOPERATIVE FOLLOW-UP
 Cardiomegaly on x-ray film and enlarged RV
dimension on echo as well as the wide splitting of
the S2 may persist for 1 or 2 years postoperatively.
The ECG typically demonstrates RBBB (or RV
conduction disturbance).
 Atrial or nodal arrhythmias occur in 7% to 20% of
postoperative patients. Occasionally, sick sinus
syndrome, which occurs especially after the repair of
a sinus venosus defect, may require antiarrhythmic
drugs, pacemaker therapy, or both.
 Rarely, patients with residual shunt may be
administered aspirin to prevent paradoxical
embolization.

51. NATURAL HISTORY
 In patients with an ASD less than 3 mm in
size diagnosed before 3 months of age,
spontaneous closure occurs in 100% of
patients at 1½ years of age. Spontaneous
closure occurs more than 80% in patients
with defects between 3 and 8 mm before
1½ years of age. An ASD with a diameter
greater than 8 mm rarely closes
spontaneously.

52. NATURAL HISTORY
2. Most children with an ASD remain active and
asymptomatic. Rarely, congestive heart failure
(CHF) can develop in infancy.
3. If a large defect is untreated, CHF and
pulmonary hypertension develop in adults who
are in their 20s and 30s.
4. With or without surgery, atrial arrhythmias
(flutter or fibrillation) may occur in adults.
5. Infective endocarditis does not occur in
patients with isolated ASDs.
6. Cerebrovascular accident, resulting from
paradoxical embolization through an ASD, is a
rare complication.

53. Thank you