An approach to a patient with Atrial septal defect (ASD)

Definition, causes, associations, prevalence, embryology, presentations, diagnostic workup, treatment

1. [email protected]
Approach to a patient with
MBBS(DMC), FCPS(MED), MD(Card),
FACC, FESC, FRCP, FSCAI,
FCCP, FAPSC, FAPSIC, FAHA,FACP
Professor & Head of Cardiology
CMMC, Manikganj
Ex Professor of Cardiology, NICVD
05/04/2021

3. Types of congenital heart disorders
•hole in the heart –between two of the heart's
chambers (septal defect)
•narrowing of the aorta–the main large artery of the
body, called the aorta, is narrower than normal
(coarctation)
•narrowing of the valve, which controls the flow of
blood out of heart to the lungs(pulmonary valve
stenosis)
•the pulmonary artery and the aorta swap places
(transposition of the great arteries)

15. Approach to a patient with Congenital
Heart disease
•1. Look for cyanosis
•2. auscultate murmur and evaluation
•3. look for age
•4. CXR findings evaluation-cardiac
shadow and lunsfindings

16. Congenital Heart Disease (CHD)
Look for
central cyanosis
Acyanotic Cyanotic
Auscultate Murmur
PSM in LLSEESM
in ULSE
ESM
in URSE
Continuous
Machinery
in ULSE & LICLA
BSM in Left
Axilla & Radio
-femoral delay
CoAoPDA
As
RSCLA
PS/ASD
VSD
S
2Split & wideS
2Absent
ASD PS
Contd...

17. Cyanotic
Look for Age
Early (<6M)
TGA, TAPVD (obs)
SevreTOF, Tr. Ar.
Tricuspid Atresia (TA)
with small shunt
pulmonary atresia (PA)
(without shunt)
Late (>6M)
TOF
TAPVD (without obs)
TA (with large shunt
Ebstein’sAnomaly (EA)
S.V, A-V canal defect
Chest Radiography
Plethoric Lungs
TGA, TAPVD
Tr. Ar.
TOF, PA,
EA, TA
Oligaemic Lungs
Characteristic
Cardiac
shadow
Egg shape Figure of 8Square
shape
Boot shapeBox shapeLarge RA
cardiomegaly
TGA TAPVD Tr, Ar TOF EA
PA/TA

18. Causes/ Associations of ASD
Down syndrome
Ebstein'sanomaly
Fetal alcohol syndrome
Holt–Oramsyndrome
Lutembacher'ssyndrome

19. Causes/Associations of ASD
Down syndrome
have higher rates of ASDs, especially a
particulartype that involves the
ventricular wall. one half patients
have some type of septaldefect.
Ebstein'sanomaly
about 50% of individuals have
an associated shunt between the
right and left atria, either an atrial septal
defect or apatent foramen ovale.

20. Causes/ associations of ASD
Fetal alcohol syndrome
about one in four patients has
either an ASD or aVSD
Holt–Oramsyndrome
both osteumsecundumand
primumtypes of ASD are associated
Lutembacher'ssyndrome
presence of a congenital ASD
along with acquired mitral stenosis

21. Prevalence of ASD

23. Embryology of Inter atrial septum

24. Embryology of Inter atrial septum

25. Embryology of Inter atrial septum

26. Embryology of Inter atrial septum

27. Embryology of Inter atrial septum

28. Anatomy of Inter atrial septum

29. Clinical Presentation
Complications like cardiac
arrhythmia or frequent respiratory
tract infections.
Decompression sickness
Eisenmenger'ssyndrome
Paradoxical embolus
Migraine

30. Clinical Presentation
Complications
Due to the communication between the atria , disease entities or
complications from the condition are possible.
with an uncorrected atrial septaldefect , patients may be at
increased risk for developing a cardiac arrhythmia, as well as more
frequent respiratory infections.
Decompression sickness
ASDs, and particularly PFOs, are a predisposing venous blood
carrying inert gases, such asheliumornitrogen does not pass
through the lungs.
The only way to release the excess inert gases from the body is to
pass the blood carrying the inert gases through the lungs to be
exhaled. If some of the inert gas-laden blood passes through the
PFO, it avoids the lungs and the inert gas is more likely to form large
bubbles in the arterial blood stream causing decompression sickness.

31. Clinical Presentation
Eisenmenger'ssyndrome
If a net flow of blood exists from the left atrium to the right atrium,
called a left-to-right shunt, then an increase in the blood flow
through the lungs happens.
Initially, this increased blood flow is asymptomatic, but if it persists,
the pulmonary blood vessels may stiffen, causing pulmonary
hypertension, which increases the pressures
in the right side of the heart, leading to the
reversal of the shunt into a right-to-left shunt.
Reversal of the shunt occurs, and the blood
flowing in the opposite direction through the ASD
is called Eisenmenger'ssyndrome, a rare and late
complication of an ASD.

32. Clinical Presentation
Paradoxical embolus
•Venousthrombusare quite common. Embolizationsnormally go to the lung and
causepulmonary emboli. In an individual with ASD, these emboli can potentially
enter the arterial system, which can cause any phenomenon attributed to acute
stoppage of blood to a portion of the body, includingcerebrovascular
accident(stroke), infarction of thespleenorintestines, or even a distal extremity
(i.e., finger or toe).
•This is known as a paradoxical embolus because the clot material paradoxically
enters the arterial system instead of going to the lungs.
Migraine
•a proportion of cases of migraine may be caused by PFO.
•closure of a PFO can reduce symptoms in certain cases.
•In a largerandomized controlled trial, the higher prevalence of PFO
in migraine patients was confirmed, but migraine headache
cessation was not more prevalent in the group of migraine patients
who underwent closure of their PFOs.

33. Anatomical Types of Atrial septal defect
SecundumASD (80% of ASDs;
located in the region of the fossa
ovalisand its surrounding)
PrimumASD (15%, synonym:
partial atrioventricularseptaldefect
(AVSD), located near the crux, AV
valves are typically malformed
resulting in various degrees of
regurgitation (esp. Mitral)

34. Anatomical Types of Atrial septal defect
Superior sinus venosusdefect (5%,
located near the superior vena cava (SVC)
entry, associated with partial or complete
connection of right pulmonary veins to
SVC/right atrium (RA)
Inferior sinus venosusdefect (1%, located
near the inferior vena cava (IVC) entry)
Unroofed coronary sinus (1%,
separation from the left atrium can be
partially or completely missing)

35. Anatomical Types of Atrial septal defect

36. Anatomical Types of Atrial septal defect

37. Atrial septal defect

39. Pathophysiology of Atrial septal defect
•Naturally L to R shunt (higher BP in LA)
•Volume overloading of RV –dilation RA+RV
•Arrhythmias (Atrial fibrillation, flutter) (5th decade)
•Increase of transpulmonaryflow –reactive higher
pulmonary vascular resistance
•severe PAH (only in 5%) and bidirectional shunt
(Eisenmengerphysiology)
•Paradoxical embolism (thrombus from lower limb veins
through ASD to systemic circulation e.g. CNS)

40. Pathophysiology of Atrial septal defect
The degree of left to right shunting is dependent on:
• the size of the defect
• the relative compliance of the
right ventricle and left ventricle
and
• the relative vascular resistance in
the pulmonary and systemic
circulations.

41. Pathophysiology of Atrial septal defect
In moderate-to-large defects, a considerable shunt of
oxygenated blood flows from the left to the right
atrium Volume overload and dilation of the
right atrium and ventricleThe tricuspid and
pulmonary annuli may dilate and become
incompetent Increased flow into the lungs
Pulmonary arteries, capillaries & the veins are
dilated Flow-related pulmonary artery
hypertension Medial hypertrophy of
pulmonary arteries and muscularizationof the arterioles
resulting in pulmonary vascular obstructive disease
Reversal of the shunt Eisenmengersyndrome

42. Diagnostic Workup
•Most individuals with a significant ASD are
diagnosedin uteroor in early childhood with the
use ofultrasonographyorauscultationof theheart
soundsduringphysical examination.
•Some individuals with an ASD have surgical
correction of their ASD during childhood.
•The development of signs and symptoms due to an
ASD are related to the size of the intracardiac
shunt.
•Individuals with a larger shunt tend to present
with symptoms at a younger age.

43. Diagnostic Workup
•Adults with an uncorrected ASD present with
symptoms of dyspnea on exertion,congestive
heart failure, orcerebrovascular accident.
•They may be noted on routine testing to have an
abnormalchest X-rayor an abnormalECGand may
haveatrial fibrillation.
•If the ASD causes a left-to-right shunt, the
pulmonary vasculature in both lungs may appear
dilated on chest X-ray, due to the increase in
pulmonary blood flow.

44. Diagnostic Workup(Physical examination)
Thephysical findingsin an adult with an ASD include those related
directly to the intracardiacshunt and those that are secondary to
theright heart failurethat may be present in these individuals.
In unaffected individuals, respiratory variations occur in
thesplitting of the second heart sound(S
2). During respiratory
inspiration, the negative intrathoracicpressure causes increased
blood return into the right side of the heart.
The increased blood volume in the right ventricle causes the
pulmonic valve to stay open longer during ventricular systole.
This causes a normal delay in the P
2component of S
2.
During expiration, the positive intrathoracicpressure causes
decreased blood return to the right side of the heart.
The reduced volume in the right ventricle allows the pulmonic valve
to close earlier at the end of ventricular systole, causing P
2to occur
earlier.

45. Diagnostic Workup(Physical examination)
In individuals with an ASD, a fixed splitting of S
2occurs
because the extra blood return during inspiration gets
equalized between the left and right atria due to the
communication that exists between the atria in
individuals with ASD.
The right ventricle can be thought of as continuously
overloaded because of the left-to-right shunt, producing
a widely split S2.
Because the atria are linked via the atrial septaldefect,
inspiration produces no net pressure change between
them, and has no effect on the splitting of S2.
Thus, S2 is split to the same degree during inspiration as
expiration, and is said to be “fixed”.

46. Diagnostics of noncyanotic heart
disease
features ASD VSD PDA
X RAY
Cardiomegalywith enlargement
of the RA and right ventricle (RV)
may be present.
A prominent pulmonary artery
(PA) segment and increased
pulmonary vascular markings are
seen
when the shunt is significant.
Cardiomegalyof varying degrees
is present and involves the LA,
left ventricle (LV)
increase in
pulmonary vascular markings .
Cardiomegalyof varying
degrees occurs in moderate-to
large-shunt PDA with
enlargement of the
LA, LV, and ascending aorta.
Pulmonary vascular markings
are increased.
ECG
Right axis deviation of +90 to
+180 degrees and mild right
ventricular hypertrophy (RVH) or
right bundle branch block (RBBB)
with an rsR' pattern in V1 are
typical findings. In about 50% of
the
patients with sinus venosusASD,
the P axis is less than 30 degrees.
With a moderate VSD, left
ventricular hypertrophy (LVH)
and occasional left atrial
hypertrophy
(LAH) may be seen.
With a large defect, the ECG
shows biventricular hypertrophy
(BVH) with or without LAH
If pulmonary vascular
obstructive disease develops,
the ECG shows RVH only
A normal ECG or LVH is seen
with small to
moderate PDA. BVH is seen
with large PDA. If pulmonary
vascular obstructive disease
develops, RVH is
present
Diagnostic Workup(X ray & ECG)

47. Diagnostic Workup(ECG)
The ECG findings in atrial septaldefect vary
with the type of defect the individual has.
Individuals with atrial septaldefects may
have a prolonged PR interval.
The prolongation of the PR interval is
probably due to the enlargement of the
atria common in ASDs and the increased
distance due to the defect itself.
Both of these can cause an increased distance of
internodalconduction from theSA nodeto
theAV node.

48. Diagnostic Workup(ECG)
In addition to the PR prolongation, individuals
with a primumASD have a left axis deviation of
the QRS complex
those with a secundumASD have a right axis
deviation of the QRS complex.
Individuals with a sinus venosusASD exhibit a left
axis deviation of the P wave (not the QRS
complex).
A common finding in the ECG is the presence of
incompleteright bundle branch block, which is so
characteristic that if it is absent, the diagnosis of
ASD should be reconsidered.

49. Diagnostic Workup(Echocardiography)
In transthoracicechocardiography, an atrial septaldefect
may be seen on color flow imaging as a jet of blood from
the left atrium to the right atrium.
If agitated saline is injected into a peripheral vein during
echocardiography, small air bubbles can be seen on
echocardiographic imaging.
Bubbles traveling across an ASD may be seen either at
rest or during a cough.
Because better visualization of the atria is achieved with
transesophagealechocardiography, this test may be
performed in individuals with a suspected ASD which is
not visualized on transthoracic imaging.

50. Diagnostic Workup(Echocardiography)
Newer techniques to visualize these defects involve
intracardiacimaging with special catheters typically
placed in the venous system and advanced to the level of
the heart.
This type of imaging is becoming more common and
involves only mild sedation for the patient typically.
If the individual has adequate echocardiographic
windows, use of the echocardiogram to measure the
cardiac output of the left ventricle and the right ventricle
independently is possible.
In this way, the shunt fraction can be estimated using
echocardiography.

51. Diagnostic Workup
(Transcranialdopplerbubble study)
A less invasive method for detecting
a PFO or other ASDs than
transesophagalultrasound
istranscranialDopplerwith bubble
contrast.
This method reveals the cerebral
impact of the ASD or PFO.

52. Treatment( PFO)
Most patients with a PFO are asymptomatic and
do not require any specific treatment.
However, those who develop a stroke require
further workup to identify the etiology.
In those where a comprehensive evaluation is
performed and an obvious etiology is not
identified, they are defined as having a
cryptogenic stroke.
The mechanism for stroke is such individuals is
likely embolic due to paradoxical emboli, a left
atrial appendage clot, a clot on the inter-atrial
septum, or within the PFO tunnel.

53. Treatment( PFO closure)
patients with PFO and cryptogenic
stroke were treated with antiplatelet
therapy only.
Previous studies did not identify a clear
benefit of PFO closure over antiplatelet
therapy in reducing recurrent ischemic
stroke.
A variety of PFO closure devices may be
implanted via catheter-based procedures.

54. Treatment( PFO closure)
based on new evidenceand systematic review
,percutaneous PFO closure in addition to
antiplatelet therapy is suggested for all who
meet all the following criteria:
Age ≤ 60 years at onset of first stroke,
Embolic-appearing cryptogenicischemic
stroke, and
PFO with a right-to-leftinteratrial
shuntdetected bybubble study
(echocardiogram)

55. Treatment ( Medical therapy)
PFO closure is more effective at reducing recurrent
ischemic stroke when compared to medical therapy.
antiplatelet and anticoagulation were combined in the
medical therapy arm.
anticoagulation should be superior to antiplatelet
therapy at reducing risk of recurrent stroke.
A recent review of the literature supports this hypothesis
recommending anticoagulation over the use of
antiplatelet therapy in patients with PFO and cryptogenic
stroke.
However, more evidence is required comparing of PFO
closure with anticoagulation or anticoagulation with
antiplatelet therapy.

56. Treatment ( Atrial septalDefect)
Once someone is found to have an atrial
septaldefect, a determination of whether it
should be corrected is typically made.
If the atrial septaldefect is causing the right
ventricle to enlarge, a secundumatrial
septaldefect should generally be closed.
If the ASD is not causing problems the defect may
simply be checked every two or three years.
Methods of closure of an ASD include
surgical closure and percutaneous closure

57. Treatment ( ASD)
(Evaluation prior to correction)
evaluation to see the severity of the individual's pulmonary
hypertension and whether it is reversible.
closure of an ASD may be recommended for prevention
purposes, to avoid such a complication in the first place.
Pulmonary hypertension is not always present in adults who
are diagnosed with an ASD in adulthood.
If pulmonary hypertension is present, the evaluation may
include a right heart catheterization.
Individuals with a pulmonary vascular resistance (PVR) less
than 7 wood units show regression of symptoms
(includingNYHA functional class).
individuals with a PVR greater than 15 wood units have
increased mortality associated with closure of the ASD.

58. If the pulmonary arterial pressure is more than
two-thirds of the systemic systolic pressure, a net
left-to-right shunt should occur at least 1.5:1 or
evidence of reversibility of the shunt when given
pulmonary artery vasodilators prior to surgery.
If Eisenmenger'sphysiology has set in, the right-
to-left shunt must be shown to be reversible with
pulmonary artery vasodilators prior to surgery.
Surgical mortality due to closure of an ASD is
lowest when the procedure is performed prior to
the development of significant pulmonary
hypertension.
Treatment ( ASD)
(Evaluation prior to correction)

59. The lowest mortality rates are achieved in individuals with a
pulmonary artery systolic pressure less than 40 mmHg.
IfEisenmenger'ssyndromehas occurred, a significant risk
of mortality exists regardless of the method of closure of
the ASD.
In individuals who have developed Eisenmenger's
syndrome, the pressure in the right ventricle has raised
high enough to reverse the shunt in the atria.
If the ASD is then closed, theafterloadthat the right
ventricle has to act against has suddenly increased.
This may cause immediate right ventricular failure, since
it may not be able to pump the blood against the
pulmonary hypertension.
Treatment ( ASD)
(Evaluation prior to correction)

60. Treatment ( ASD)(Surgical closure)
Surgical closure of an ASD involves
opening up at least one atrium and closing
the defect with a patch under direct
visualization.

61. Treatment ( ASD)(Device closure)
Percutaneous device closure involves the passage
of a catheter into the heart through the femoral
vein guided by fluoroscopy and echocardiography.
Device has discs that can expand to a variety of
diameters at the end of the catheter.
The catheter is placed in the right femoral vein
and guided into the right atrium.
The catheter is guided through
the atrial septalwall and one disc
(left atrial) isopenedand pulled
into place.

62. Treatment ( ASD)(Device closure)
Once this occurs, the other disc (right atrial) is
opened in place and the device is inserted into the
septalwall.
This type of PFO closure is more effective than
drug or other medical therapies for decreasing the
risk of future thromboembolism.
The most common adverse effect of PFO device
closure is new-onset atrial fibrillation.
Other complications, all rare, include device
migration, erosion and embolization and device
thrombosis or formation of an inflammatory mass
with risk for recurrent ischemic stroke.

63. Treatment ( ASD)(Surgical closure)
Percutaneous closure of an ASD is currently only
indicated for the closure of secundumASDs with a
sufficient rim of tissue around the septaldefect so
that the closure device does not impinge upon the
superior vena cava, inferior vena cava or
thetricuspidormitralvalves.
TheAmplatzerSeptalOccluder(ASO) is commonly
used to close ASDs.
The ASO consists of two self-expandable round discs
connected to each other with a 4-mm waist, made up of
0.004–to 0.005-inch Nitinolwire mesh filled with Dacron
fabric.

64. Treatment ( ASD)(Surgical closure)
Implantation of the device is relatively easy.
The prevalence of residual defect is low.
The disadvantages are a thick profile of the device and
concern related to a large amount of nitinol(a nickel-
titanium compound) in the device and consequent
potential for nickel toxicity.
Percutaneous closure is the method of choice in most
centres.
Studies evaluating percutaneous ASD closure among
pediatric and adult population show that this is relatively
safer procedure and has better outcomes with increasing
hospital volume.

65. Risks of CHD