2. Ventricular Septal Defect
Henri Roger was the first man to
describe a ventricular septal
defect, in 1879 he wrote:
“A developmental defect of the heart occurs
from which cyanosis does not ensue in spite
of the fact that a communication exists
between the cavities of the two ventricles
and in spite of the fact that the admixture of
venous blood and arterial blood occurs. This
congenital defect, which is even compatible
with long life, is a simple one. It comprises a
defect in the interventricular septum”
3. INTRODUCTION
Isolated VSD - most commonly recognized CHD
2- per 1000 live birth
Forms 20 % of all CHD
50 % when associated with other major defects
.
75-80% of small VSD’s close
spontaneously by late childhood
10-15% of large VSD’s close spontaneously
60% of defects close before age 3,
and 90% before age 8
4. HISTORICAL ASPECT
Roger in 1879 - first described
Eisenmenger – 1897 - autopsy finding
Pathophysiology by Abbott (1936) & Selzer (1949)
. 1952 – Muller and Danman- pulmonary artery band
1954 - Lillehei and associates – First vsd repair
1956 – Dushane – Transventricular / Stirling – Transatrial
1961 – Kirklin- Repair of VSD in infants
1976 - Baratt-Boyes – deep hypothermia & circulatory arrest
5. The primitive cardiac tube has five zones:
the arterial trunk
the bulbus cordis )
the ventricle
the atrium
and the sinus venosus
V
B
V
D
A
SV
8. EMBRYOLOGY
VSD occurs during the first 8 weeks of foetal life
3 components – Interventricular muscular partition
- Endocardial cushions
- Bulbar ridges that separate great vessels
.
9. Four cushions (AVC) have
developed at the A/V junction; the
superior and inferior cushions will
meet to divide the AV orifice (AVO)
into the tricuspid and mitral valves.
The inferior septal crest (VS)
will aim to meet the divided valve
where the cushions fuse.
10. Formation of IV septum
IV septum upwards from the
floor of the bulboventricular
cavity,division into rt and lt
halves.It meets fused AV
cushions and partially fuse
with them.
Two ridges rt and lt arise in
conical upper part of
bulboventricular cavity.fuse
with each other to form bulbar
septum.
Gap persists between the
two-filled by proliferation of
tissue from the AV cushions.
11. Membranous IV septum
Ant part separates
rt and left ventricles.
Post part separates
rt atrium and left
ventricle.
This is because the
interatrial and
interventricular
septum don’t meet
in the midline.
14. What if?..............
- then you get
the truncal septum fails to fuse with the septal crest?
- perimembraneous VSD
the truncal septum is deviated to the PA side?
- tetralogy of Fallot
the truncal septum fails to develop?
- truncus arteriosus
the ventricular septum fails to reach the AV valve?
- AV septal defects
the arterial trunk stays over the RV but does divide?
- double outlet RV
the aortic valve pushes up and right instead of the pulmonary?
- transposition of the great vessels
the ventricles fail to centralise over the AV valve
- double inlet left ventricle (commonest form of single ventricle)
the loop is to the left?
- ventricular inversion (RV on the left, LV on the right)
15. Associated Defects
Left Heart Defects
– Aortic stenosis
– Coarctation of the aorta
Right Heart Defects
– Tetrology of Fallot
– Double Outlet Right Ventricle
Truncus Arteriosus
Some single ventricle (e.g. Tricuspid atresia, double
inlet left ventricle)
16. Chromosomal Disorders
associated with VSD
Trisomy 21: 40% of T21 will have VSD
Trisomy 13, 18: 18% of T13, 31% of T18 will have VSD
22q11 deletion:
– Tetrology of Fallot is most common anomaly
– VSD with or without aortic arch anomaly is second most
common
Holt-Oram (Hand-heart syndrome): TBX5 gene found on
Chromosome 12
Recurrence risk for VSD based on parental VSD
– Paternal 2%
– Maternal 6-10%
19. Ventricular Septum
The membranous septum-The septal leaflet of the tricuspid valve divides
the membranous septum into 2 components, the pars atrioventricularis
and the pars interventricularis.1
The muscular septum is a nonplanar structure that can be divided into
inlet, trabecular, and infundibular components.
An inlet VSD has no muscular rim between the defect and the
atrioventricular valve annulus.
The trabecular septum is the largest part of the interventricular septum.
The location of defects in the trabecular septum can be classified as
anterior, midmuscular, apical, and posterior
The infundibular septum separates the right and left ventricular outflow
tracts. On the right side, it is bordered by the line from the membranous
septum to the papillary muscle of the conus inferiorly and the semilunar
valves superiorly.
20. Nomenclature / Classification
TYPE IConal,Supracristal,
Infundibular,Subarterial
TYPE II –
Paramembranous
TYPE IIIInlet/ AV canal type
Type IV –
Muscular
23. Lesion Size
• Restrictive VSD
– < 0.5 cm2 (Smaller than Ao valve orifice area)
– Small L to R shunt
– Normal RV output
– 75% spontaneously close < 2yrs
• Non-restrictive VSD
– > 1.0 cm2 (Equal to or greater than to Ao valve
orifice area)
– Equal RV and LV pressures
– Large hemodynamically significant L to R shunt
– Rarely close spontaneously
24. Based on size
1. Size
1) Large
: 2/3rd of aortic annular size or > 15mm
or > 1cm/sq.m of BSA
Peak RV sys = LV sys pressure
2) Moderate : half of aortic annular size 5 to 15mm
RV pressure to ½ of LV
Qp/Os>2.0
3) Small
: One third of aortic annular size
insufficient size to raise RV pressure &
Qp/Qs < 1.75
25. TYPE I VSD
Conal,Supracristal,Infundibular,
Subarterial
Maldevelopment of bulbotruncal system
Located within infundibular portion of
RVOT
Superior margin – no muscular tissue
Inferior margin – defect is muscular
Can extend upto right or sometimes
non-coronary cusps of the aortic valve
Conduction system is not in surgical
proximity
28. TYPE II VSD
Also called Conoventricular defects.
Most common (80%)
Margins include membranous septum or
remnant
May have extensions into inlet, outlet or
trabecular septum
Postero-inferior margin very close to the
antero-septal commissure of the
Tricuspid valve
Can extend upto non-coronary cusp of
aortic valve
Danger area- inferior and posterior
region of defect
32. TYPE III VSD
AV Canal type / Inlet VSDs
Form about – 5% of all VSDs
Located posteriorly – subjacent to TV
septal leaflet in inlet portion
Superior border- may extend to the
annulus of tricuspid valve
Conduction system at risk – close
proximity to AV node
Guide- apical area of Triangle of koch
Common bundle courses around infr.
aspect of defect
35. TYPE IV VSD
Muscle tissue all around the
defect
May be either anterior, in the inlet
septum, mid-muscular or apical
Classification according to
location is important because it
determines the approach for
surgical closure.
– Inlet and mid-muscular ----- RA
approach
– Anterior ------- Rt. Ventriculotomy
– Apical ------ May require left
ventriculotomy
May be Single/ multiple
Swiss Cheese VSD
38. Pathophysiology
Two determinants
– Size of defect
– Pulmonary vascular resistance
These determine
– Pressure gradient across VSD
– Shunt volume across VSD
After birth PVR falls ------ Large
flow across shunt if large VSD
Causes increased PA pressure
(initially flow related), increased
PV return, hence LA
enlargement and LV overload
PH initially flow related and
reversible
39. Pathophysiology
Later ----- Intimal proliferation and medial hypertrophy leads to
fixed irreversible PH
Flow through the lungs decreases as PVR increases, hence
shunt volume decreases
Eventually PVR > SVR, hence R L shunt across VSD
Cyanosis Eisenmengerised VSD
Shunt calculated by Fick’s principle Qp/Qs
Aortic O2 % sat - Central Venous O2 % sat
Pulm. Vein O2 % sat – Pulm. Art O2 % sat
With small VSDs, there is resistance to flow across the VSD
hence Qp/Qs is rarely > 1.5
With moderate VSDs, Qp/Qs is between 1.5 and 2.5, and is
less likely to cause pulm vasc disease
42. HEATH- EDWARD CLASSIFICATION
Grade I - hypertrophy of the media of small muscular arteries and arterioles.
Grade II - intimal cellular proliferation in addition to medial hypertrophy.
Grade III - progressive intimal proliferation and concentric fibrosis.
Grade IV - "plexiform lesions"
Grade V - angiomatous and cavernous lesions and hyalinization of intimal
fibrosis.
Grade VI - necrotizing arteritis.
43. Natural History
Spontaneous closure is
known, primarily with
perimembranous and
muscular VSDs.
Subarterial and inlet VSDs
rarely close
– Chances differ with age at
detection
At 1 month 80% of large
VSDs close
At 6 months 50%
At 12 months 25%
44. Natural History
Patients with large vsd- symptom develop soon after
birth.
CHF manifested by- dyspnea/rptd.pulmonary
infn/hepatomegaly/sweating/failure to thrive.
Irreversible pulmonary vascular disease after 1-2 yrs
of age.
Some children with isolated vsd develop Subpulmonic
stenosis- pt. not at risk of pulmonary vascular disease
45. VSD IN ADULT
SVT – AF prevalent with increasing age.
VSD+ AR – High risk of bacterial endocarditis
Right sided failure- due to pulmonary stenosis
Left sided failure- in pts. of aortic valve prolapse.
Eisenmenger complex- 2nd & 3rd decade of life
Pregnancy- spontaneous abortion/small-for-date babies
Mortality- 27% by 20 years & 69% by 60 years.
46.
47. CLINICAL FEATURES
Grade I
Small ventricular septal defect (less than 1.5 cm2) Patient is asymptomatic. Murmur can be
present since a few days after birth.
Grade II
Frequent respiratory tract infections. CHF (rare). Cyanosis is absent even during exercise.
Functional aerobic capacity is usually moderately reduced with early fatigability but unusual
CHF.
Grade III
More frequent respiratory tract infections. Defective growth. Moderate cyanosis at times with
exertion Congestive heart failure frequent in the first years of life (one of the most frequent
causes of CHF during the first year of life). Functional capacity markedly reduced.
Grade IV or Eisenmenger Complex
48.
49. EISENMENGER COMPLEX
• Infants with Eisenmenger may become easily fatigued,
especially during crying spells and at feeding time
• Low tolerance for extra exertion
• Shortness of Breath (dyspnea) and/or rapid breathing
• Fainting (syncope)
• Difficulty eating, breathing or sucking
• Poor weight gain
• Slow growth or other physical retardation
50.
51.
52. CLINICAL FINDINGS
•
Pulse pressure is relatively wide
•
Precordium is hyperkinetic with a systolic thrill at LSB
•
S1&S2 are masked by a PSM at Lt.sternal border ,max. intensity of the
murmur is best heard at 3rd,4th&5th Lt interspace.Also well heard at the
2nd space but not conducted beyond apex
•
Lt. 2nd space –widely split &variable accentuated P2
•
Delayed diastolic murmur at the apex &S3
•
Presence of mid-diastolic ,low pitched rumble at the apex is caused by
increased flow across the mitral valve &indicates Qp:Qs=2:1/greater
•
Maladie de Roger –small VSD presenting in older children as a loud
PSM w/o other significant hemodynamic changes
53. ECG
Size of Defect
Results
Small restrictive VSDs
Normal tracing
Medium-sized VSDs
Broad, notched P wave characteristic of left
atrial overload
• Signs of LV volume overload — deep Q
and tall R waves with tall T waves in leads
V5 and V6
• Signs of atrial fibrillation are often
present
Large VSDs
Right ventricular hypertrophy with right-axis
deviation.
With further progression, the ECG shows
biventricular hypertrophy; P waves may be
notched or peaked.
54. ECG
May show right/left or combined ventricular
hypertrophy
Presence of RAD represents elevated RVP
and PAP
Postoperative RBBB is common
CHEST X-RAY
Cardiomegaly :
proportional to the
volume overload.
Mainly LV, LA and RV
enlargement.
Increased pulmonary
blood flow, PAH.
Unless LA is significantly
enlarged its difficult to
differentiate from ASD.
RV may not be as
enlarged as anticipated
as it receives the shunt
into its outflow tract.
56. 42-year-old woman with Eisenmenger complex, demonstrating atrial fibrillation with
right axis deviation, right ventricular hypertrophy, right bundle-branch block, and premature
ventricular beat.
57. Ventricular septal defect in a 7-month-old.
Frontal(A)and lateral (B) views of the chest show moderate cardiac enlargement
including right atrial, right ventricular, and left atrial enlargement with posterior
displacement of the left main stem bronchus (arrow in B) and increased pulmonary
58.
59. 2D -ECHO
Determine vsd location
LV outflow morphology
Aortic valve
involvement
AV valve chordal attachment
Septal trabeculations
may cause multiple
reflections and obscure
small defects
Prominent bulging of
tissue into the RV :
aneurysmal
perimembranous VSD
63. Cardiac catheterization
Identification of Multiple VSDs
Cardiac catheterization can quantify shunt volume
and pulmonary arterial resistance.
Step-up in oxygen saturation may be detected in
the pulmonary artery rather than in the right
ventricular cavity because of streaming of the
shunted blood into the pulmonic trunk.
If aortic valve prolapse is significant, left-to-right
shunting by oximetry may be fairly unremarkable,
because the ventricular septal defect (VSD) in
such cases is partially obstructed.
64. CATH GRADING
Grade I
Right atrium and right ventricular pressures are normal, due to the low volume shunt. Oxymetry can be
misleading, showing only a mild step up in oxygen saturation at ventricular level.
The passage to the left ventricle with the catheter is often possible.
Grade II
Elevation of right ventricular pressure and pulmonary hyperdynamics hypertension (moderate) due to large
pulmonary flow.
Blood oxygen measurements will show typical right ventricular oxygen step up.
If the defect is located over the Crista Supraventricularis the step up can only be seen at the pulmonary
artery level. (The maximal normal step up between vena cava and atrium is 2 Vol % and between RV and
MPA 0.5 Vol %; any difference over such figures must be considered abnormal.)
.
Grade III
The pressure tends to equalize between right and left ventricles but with a still predominant left to right
shunt. Significant blood oxygen step up is noted.
With exertion, the normal peripheral arterial oxygen saturation is reduced. Significant pulmonary
hypertension exists (close to systemic). There is marked R.V.H.
Grade IV: Eisenmenger Complex
65. Angiocardiography
Contrast injected into
LV will localise the
site & size of the
defect
Contrast into the
pulmonary artery will
demonstrate the L-R
shunt.
Gerbode defect : RA
opacifies from the LV
injection
72. TREATMENT PROTOCOL
SMALL VSD
- No medication or surgery if asymptomatic
– 75-80% close by 2 years . Observation
MODERATE / LARGE VSD - Treatment of CHF
Determining when to repair
INTERVENTION
Decompensated CHF
Compensated CHF with:
– Large hemodynamically significant VSD - L to R shunting
with Qp/Qs > 2:1, even if asymptomatic, ideally before 1
year
– Growth failure, unresponsive to medical therapy is an
indication for surgery
74. Indications for intervention
Significant VSD: symptomatic without irreversible pulmonary HTN
* Qp/Qs > 1.5
* PA systolic pressure > 50 mm Hg
* Increased LV and LA size
* Deteriorating LV function
Perimembranous VSD with more than mild AR + recurrent
endocarditis.
Subarterial VSD - High incidence of aortic valve prolapse/ AI
Children without irreversible pulmonary HTN
* significant symptoms failing to respond to medication
* elective surgery (performed between 3 ~ 9 m/o)
Pulmonary HTN
* PA resistance < 7 Wood units
* Net left-to-right shunt of at least 1.5
* Irreversible
75. SURGICAL CONSIDERATION
Preoperative VSD location
Avoidance of injury to conduction pathways.
Operative technique needed to secure the closure
5 operative approaches -
RIGHT ATRIAL
TRANSPULMONARY
TRANSAORTIC
RIGHT VENTRICULAR
LEFT VENTRICULAR
76. RIGHT ATRIAL APPROACH
Most frequently used
Used for – Paramembranous/ Inlet /Muscular/LV & RA types
APICAL & SWISS Cheese defect – limited left apical ventricular
incision may be required
77.
78. Shallow Stitching Close to the Rim of the Ventricular
Septal Defect Eliminates Injury to the Right Bundle Branch
81. TRANSPULMONARY ARTERY
Used for repair of Conal ( Supracristal vsd)
Conal Vsd – importance of patch closure
Treacherous situation- Prolapsed aortic valve leaflet
partially occlude the defect.
Avoiding injury to Aortic valve leaflet .
Repairing superior aspect of VSD
Combined approach for AI
may
82.
83. TRANSAORTIC APPROACH
Need for concomitant correction – aortic valvuloplasty / valvar
or subvalvar stenosis.
Incision- curved incision over Aortic valve commisure
Absence of superior muscular or fibrous rim of the defect.
Used for DORV with subaortic VSD
84. RV APPROACH
2 types- TRANSVERSE/ VERTICAL
Important to examine epicardial coronary artery distribution
Indications- inaccesibility from rt .atrium /pulmonary artery
- defect extending into infundibular septum
- presence of obstructive infundibular muscle bundles
- difficulty exposing inferior margin of conal defect
Patch closure by
RV approach
85. Apical Muscular VSD
Patch Closure via RVtomy
(A) Trabeculations overlying the VSD are taken down.
(B) Interrupted pledgetted sutures are placed full thickness at the superior margin of
the defect, maintaining the pledgets on the left ventricular side
(C) Closure of the VSD with a Dacron patch
86. LV APPROACH
Rarely used
Vertical / Transverse incision
Limited to certain type of trabecular VSDs- multiple
apical,swiss cheese
Easier to patch from LV side because of smooth septum
LV incision avoided to prevent long term ventricular
dysfunction.
