UNDERSTANDING CONGENITAL HEART DISEASES

1. Introduction
to
Congenital Heart Disease
ALI AHMED MAHAREAK, MD
Lecturer Of Anesthesiology And Intensive
Care , Al-Azhar University
Ali_m7areak@yahoo.com

2. Learning Objectives
Applied anatomy of the Heart
Embryo-fetal circulation and Changes at birth
Classification of CHD
Pathophysiology of CHD
The concepts of shunting, single ventricle
physiology, and intercirculatory mixing
Pulmonary vascular occlusive disease
Specific CHD Defects

3. Heart anatomy
 Four chamber muscular organ
 The overall shape of the
heart is that of a three-sided
pyramid
 Located in the mediastinum
Behind sternum
Between 2nd and 6th ribs
Between T5-T8
 Apex of heart
Located at the 5th intercostal
space

4. Heart position in thorax

5. Chambers of the Heart
 Atria – two superior chambers
“Receiving chambers”
Blood from veins enters atria
Ventricles – two inferior
chambers
“pumping chambers”
Thick muscular walls to
increase force of pumping
action
Left > right
Separated by interventricular
septum

6. Valves of the Heart
Tricuspid” valve
 RA to RV
 three leaflets septal,
anterosuperior, and inferior
Mitral valve
LA to LV
Two leaflets ,The aortic (or anterior)
leaflet and Posterior leaflet
Pulmonary valve
RV to pulmonary trunk
Aortic valve
LV to aorta
three leaflets, the right coronary
cusp, the left coronary cusp, and the
non-coronary cusp.

8. Heart anatomy
 The surgical anatomy of the heart is best
understood when the position of the cardiac
chambers and great vessels is known
 One third of the cardiac mass lies to the right
of the midline, and two thirds to the left.
 The long axis of the heart is orientedfrom the
left epigastrium to the right shoulder

9. Heart anatomy
•The short axis, which corresponds to the plane of
the atrioventricular groove, is oblique and is
oriented closer to the vertical than to the horizontal
plane
careful study of this short axis,
 First, the atrial chambers lie to the right of their
corresponding ventricles.
 Second, the right atrium and ventricle lie anterior
to their left-sided counterparts
 The septal structures between them are
obliquely oriented

11. Embryo-fetal circulation
The placenta provides gas
exchange in the fetus.
Changes at birth are directly
related to the exclusion of the
placenta and the establishment of
the lungs as the unit of gas
exchange
Oxygenated blood flows from
the placenta To the fetus via the
umbilical vein

12.  After reaching fetus the blood flows through the inferior
vena cava
 IVC Empties into the right atrium of the heart
 The blood then passes to the left atrium through the
foramen ovale
 Only about one-third of this blood reaches the lungs
(due to high flow resistance since the lungs are not yet
expanded, and due to hypoxic vasoconstriction
Embryo-fetal circulation
Three shunts are present in fetal life:
1. Ductus venosus: connects the umbilical vein to the
inferior vena cava
2. Ductus arteriosus: connects the main pulmonary
artery to the aorta
3. Foramen ovale: anatomic opening between the right
and left atrium.

13. Flow Chart of Fetal Circulation

14. Changes at birth
o Clamping the cord shuts down low-
pressure system
o Increased atmospheric pressure causes
lungs to inflate with oxygen
o Lungs now become a low-pressure
system
o Pressure from blood flow in the lt side
of the heart foramen ovale closure
o Closure of the ductus arteriosus :
o functional closure within 1st day of life
and permanent anatomic closure after
2-3 weeks

15. Fetal vs. Infant Circulation
Fetal
1. Low pressure system
2. Right to left shunting
3. Lungs non functional
4. Increased pulmonary
resistance
5. Decreased systemic
resistance
Infant
1. High pressure system
2. Left to right blood
flow
3. Lungs functional
4. Decreased
pulmonary resistance
5. Increased systemic
resistance

16. Classification of CHD
A cyanotic
Heart Disease
Cyanotic Heart
disease
Increase pulmonary blood flow
Obstruction of blood flow
Decrease pulmonary blood flow
Mixed blood flow

17. A Cyanotic Heart Defect
A Cyanotic
Increased in pulmonary
blood flow
1. ASD 5-10%
2. VSD 25 %
3. AVC
4. PDA
Obstruction of blood
flow form ventricle
1.Pulmonary stenosis
2.Aortic stenosis
3.Coarctation of the Aorta

18. Cyanotic Heart Defect
Cyanotic
Decreased pulmonary
blood flow
Tetralogy of Fallot (TOF) 10%
Tricuspid atresia (TA)
Pulmonary atresia (PA) / critical PS
Mixed blood flow
Transposition of the great Arteries 5%
Total Anomaly pulmonary venous return
Truncus Arteriosus
Hypo plastic left Heart Syndrome
Double outlet right ventricle (DORV)

19. Pathophysiology of CHD
 The presence of shunts is the hallmark of CHD
 Anesthetic management of the patient with CHD
is dependent on a clear understanding of:
 The concepts of shunting , single ventricle physiology,
and intercirculatory mixing.
 The types and the dynamics of the anatomic shunting
process.
 The effects of congenital lesions on the development of
the pulmonary vascular system.
 The factors that influence pulmonary and systemic
vascular resistance.
 The factors responsible for producing myocardial
ischemia.

20. Shunting ,intercirculatory mixing
 Shunting is the process whereby venous return into
one circulatory system is recirculated through the
arterial outflow of the same circulatory system.
 Effective blood flow is the quantity of venous blood
from one circulatory system reaching the arterial
system of the other circulatory system.
 Effective pulmonary blood flow and effective systemic
blood flows are the flows necessary to maintain life.

21. Classification of anatomic shunts
Simple shunts
a communication (orifice) exists between pulmonary and
arterial vessels or heart chambers
 In a simple shunt, there is no fixed obstruction to outflow
from the vessels or chambers involved in the shunt.
the shunt orifice may be small (restrictive shunt) or large
(nonrestrictive)
Complex shunts
In complex anatomic shunt lesions there is obstruction to
outflow in addition to a shunt orifice
The obstruction may be at the valvular, subvalvular, or
supravalvular level
 The obstruction may be fixed (as with valvular stenosis) or
variable (as with dynamic infundibular obstruction).

22. Simple shunts

23. Single ventricle physiology
 Single ventricle physiology is used to describe the
situation wherein complete mixing of pulmonary
venous and systemic venous blood at the atrial or
ventricular level
 then distribute output to both the systemic and
pulmonary beds.
 Ventricular output is the sum of pulmonary blood flow
(Qp) and systemic blood flow (Qs).
 Distribution of systemic and pulmonary blood flow is
dependent on the relative resistances to flow
 Oxygen saturations are the same in the aorta and the
PA.

24. Single ventricle physiology

25. Pulmonary vascular occlusive disease (PVOD)
PVOD produces obstruction to pulmonary blood flow
due to structural changes in the pulmonary vasculature
The morphologic changes have three components:
increased muscularity of small pulmonary arteries,
small artery intimal hyperplasia, scarring, and
thrombosis and reduced numbers of intra-acinar
arteries
Causes of PVOD :
 Exposure to systemic arterial pressures and high
pulmonary blood flows large (nonrestrictive) VSD.
 Exposure to high blood flow large ASD
 Obstruction of pulmonary venous drainage TAPVR,
mitral atresia, congenital aortic stenosis, severe
coarctation of the aorta

26. A Cyanotic Heart Defect
A Cyanotic
Increased in pulmonary
blood flow
1. ASD
2. VSD
3. AVC
4. PDA
Obstruction of blood
flow form ventricle
1.Pulmonary stenosis
2.Aortic stenosis
3.Coarctation of the Aorta

27. Defect with increased
pulmonary blood flow
1. VSD (ventricular septal defect )
2. ASD (Atrial septal defect )
3. AVC (Atrioventricular canal defect )
4. PDA ( patent ductus arteriosus)

28. Ventricular Septal Defect
 Single most common
congenital heart
malformation,30% of all
CHD
 Defects can occur in
both the membranous
and muscular portion s
of the septum

29. Ventricular Septal Defect
Types
Size
Small VSDs < 3 mm in diameter
Moderate VSDs 3-5 mm in diameter
Large VSDs with normal PVR 6-10
mm in diameter
Site
Perimembranous (or membranous)
Infundibular (subpulmonary VSD) –
involves the RV outflow tract.
inlet VSD, almost always involves AV
valvular abnormalities
Muscular VSD – can be single or
multiple.

30. Ventricular Septal Defect
Indications for Surgical
Closure
 Large VSD w/ medically
uncontrolled .
 Ages 6-12 mo w/ large
VSD & Pulm. HTN
 Age > 24 mo w/ Qp:Qs
ratio > 2:1.

31. Atrial Septal Defects
Three major types
 Ostium secundum
o most common
o In the middle of the
septum in the region
of the foramen ovale
 Ostium primum
o Low position
o Form of AV septal
defect
 Sinus venosus
o Least common
o Positioed high in the
atrial septum
o Frequently associated
with PAPVR

32. Treatment
o Closure generally
recommended when ratio
of pulmonary to systemic
blood flow (Qp:Qs) is >
2:1
o Operation performed
electively between ages 2
and 5 years
Atrial Septal Defects

33. Atrioventricular canal defect (AVC )
Complete AVC
Low primum ASD continuous
with a posterior VSD.
Cleft in both septal leaflets of
TV/MV.
Results in a large L to R shunt at
both levels
Partial AVC
 ostium primum ASD
association with a cleft mitral
valve

34. Patent Ductus Arteriosus
 PDA results when the ductus fails to
close after birth
 More in preterm hypoxic infants
 Blood flows from aorta to the
pulmonary artery, creating a left to right
shunt
 Increased pulmonary blood flow can
result in pulmonary hypertension and
reversal of the shunt
 Medical : indomethacin 0.1-0.3 mg/kg
BID for 3 doses
 May be PDA dependent circulation
 Anesthetic Management
-Maintain high arterial pressures as low
diastolic pressure can result in decreased
organ perfusion

35. Anesthetic management goals
in Defect with RT to LT shunt
Maintain heart rate, contractility, and preload to
maintain cardiac output.
Avoid decreases in PVR:SVR ratio. The increase in
pulmonary blood flow that accompanies a reduced
PVR:SVR ratio necessitates an increase in cardiac
output to maintain systemic blood flow
 Avoid large increases in the PVR:SVR ratio. An increase
may result in production of a right-to-left shunt
In instances in which a right-to-left shunt exists,
ventilatory measures to decrease PVR should be used.
In addition, SVR must be maintained or increased

36. Cyanotic Heart Defect
Cyanotic
Decreased pulmonary
blood flow
Tetralogy of Fallot (TOF)
Tricuspid atresia (TA)
Pulmonary atresia (PA) / critical PS
Mixed blood flow
Transposition of the great Arteries
Total pulmonary venous return
Truncus Arteriosus
Hypo plastic left Heart Syndrome
Double outlet right ventricle (DORV)

38. Cyanotic CHD
WITH Decreased pulmonary
blood flow
1. Tetralogy of Fallot (TOF)
2. Tricuspid atresia (TA)
3. Pulmonary atresia (PA) / critical PS

39. Cyanotic CHD
WITH Mixed blood flow
1. Transposition of the great Arteries
2. Total pulmonary venous return
3. Truncus Arteriosus
4. Hypo plastic left Heart Syndrome
5. Double outlet right ventricle (DORV)

40. Tetraology of Fallot
1.Large outlet VSD
2.RVOT Obstruction
(infundibular or
valvular, supravalvular)
3.RVH
4.Overriding aorta
Types of TOF:
1. TOF/PS with pulmonary
stenosis
2. TOF/PA with pulmonary
atresia

41. Tetraology of Fallot TOF/PA

42. Tetraology of Fallot
Goals of Anesthetic management
 Maintain heart rate, contractility, and preload to
maintain cardiac output to prevent exacerbation of
dynamic RVOT
 Avoid increases in the PVR:SVR ratio to avoid
increase R–L shunting and reduce pulmonary blood
flow
 Use ventilatory measures to reduce PVR.
 Maintain or increase SVR. This is particularly
important when RV outflow obstruction is severe
 Aggressively treat episodes of hypercyanosis.

43. Characterized by
Hyperapnea (Rapid and deep
respirations)
Irritability and prolonged crying
 cyanosis and heart murm
Pathophysiology
 Lower SVR or inc resistance of
RVOT can increase the R-L shunt
Hypoxic Spell (“TET Spell”)
Treatment
1. Hold infant in knee-chest position
2. Morphine
3. Sodium bicarbonate to treat acidosis- decreases resp
stimulating effect of acidosis
4. Vasoconstrictor (phenylephrine)
5. Propranolol

44. Tetraology of Fallot -Surgical therapy
Palliative shunts
 to increase pulmonary blood flow
 systemic-to-pulmonary arterial shunt,
 modified Blalock–Taussig shunt (MBTS)
is used know
Definitive repair
between the ages of 2–10 months of age
Surgery is aimed at
 relieving the outflow obstruction by
resection of hypertrophied, obstructing
muscle bundles
 Trans-annular patch. across the
pulmonary valve and into the main PA.
 Finally, the VSD is closed

46. Complete Transposition of the Great
Arteries
Complete separation of the 2 circuits:
• Hypoxemic blood circulating in the body
• Hyperoxemic blood circulating in the pulmonary circuit
• Defect to permit mixing of 2 circulations- ASD, VSD,
PDA Necessary for survival

47. Truncus Arteriosus
 A single trunk leaves the heart
Gives rise to pulm, systemic,
and coronary circulations
 Large VSD

48.  Tricuspid valve is absent
 RV and PA are hypoplastic
 Associated defects- ASD, VSD, or PDA
(necessary for survival)
 Dilation of LA and LV
 Essentially single ventricle physiology
Tricuspid Atresia

50. Total Anomalous Pulmonary
Venous Return
 The pulmonary veins drain into the RA or
its venous tributaries rather than the LA
 A inter-atrial communication (ASD or PFO)
is necessary for survival
 Systemic and pulmonary venous blood are
completely mixed

52. Management of single ventricle
• The primary goal in the management of
patients with single ventricle physiology is
optimization of systemic oxygen delivery
and perfusion pressure.
• Blalock-Taussig shunt in infancy
• Bidirectional Glenn : SVC is connected to the
pulmonary arteries
• Fontan Procedure : Redirects IVC to
pulmonary arteries