Cyanotic and Acyonitic Heart Diseases

7/25/2019 Cyanotic and Acyonitic Heart Diseases

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Pediatrics lect. 29+30 21-12-2009

Dr. Iyad AL-Ammouri

[ LECTURE OUTLINE ]

Fetal circulation

Congenital Heart Diseases

o Acyanotic HD

Left to Right Shunts

ASD VSD

PDA

Outflow Obstruction

Coarctation of the Aorta

Aortic Stenosis (not req'd)

Pulmonary Stenosis (not req'd)

Cyanosis

o Cyanotic HD

TOF TGV

Truncus Arteriosus

Tricuspid Atresia

TAPVR

[ INTRODUCTION ]

Congenital heart disease (CHD): heart defects that are present at birth

and cause problems for newborns. The American Heart Association statesthat there are at least 35 distinct forms of CHD, categorized into either

acyanotic or cyanotic lesions. However, before we discuss these diseases

we need to understand fetal circulation and circulatory changes that

occur at birth.


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Fetal circulation is different than newborn

circulation in many ways.

1) The cardiac output of the fetus is

considered "total cardiac output"(CO) or "combined ventricular

output" rather than the left

ventricular (LV) and right ventricular

(RV) output. This happens because the fetus does NOT use its lungs, as

they are full of fluid. Instead of going to the lungs, the blood is directed

across the patent ductus arteriosus to the descending aorta.

2) The organ responsible for oxygenation in fetus is the placenta (NOT lung)

3) 3 communications present in the fetal circulation that close after birth:

Communication Description FunctionPatent ductus

arteriosus

(PDA):

It is an

opening which

connects the

pulmonary

artery to the

aorta

It directs blood away from lungs because

they are not used. So most of blood going to

the pulmonary artery will cross PDA to aorta.

This means the direction of flow across the

PDA in the fetus is pulmon. a aorta

(NOT aorta pulmonary a. like newborn)

Patent foramen

ovale (PFO)

It is a

foramen

present

between theleft atrium

(LA) and the

right atrium

(RA)

It directs blood from the right side of the

circulation RA LA. This blood is rich in

oxygen because it comes mainly from the

inferior vena cava (IVC) and from theplacenta across the ductus venosus. In fact,

it is the most oxygenated blood in the fetus

(60-70% of blood is saturated), so it is

directed to the most important organs in the

body! Most of the blood crosses the PFO to

the LA LV ascend. aorta head & brain

Ductus venosus It is a communication between the umbilical vein (which

carries O2-rich blood from the placenta, O2saturation

70%) across the hepatic area into the IVC.

These 3 communications close after birth (they disappear),

and the circulation divides into 2 separate parts:

1) Pulmonary circulation:"blue" (deoxygenated or

cyanotic) blood going to the lungs

2) Systemic circulation:"red" (oxygenated) blood going

to the body and end organs

*Remember: CO in the newborn is LV output only & is no longer combined.


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Congenital heart defects can be classified into 2 types of lesions:

1) Shunt lesions: presence of a shunt (communication) between pulmonary

and systemic circulations (direction of shunt either right left or left

right). As a result, blood goes to the wrong circulation (the one that

it's NOT supposed to go to) and there is mixing of the red and blue blood.2) Non-shunt lesions: obstructive or regurgitant lesions (not topic of lect)

The shunt lesions are divided into 2 major categories:

1) Left to Right shunt

2) Right to Left shunt or "cyanotic heart disease"

Obstructive lesions Regurgitant lesions

congenital lesions

cause pressure load

Examples:

o *Aortic stenosis (AS)

most common

o Supravalvar AS

o Subaortic stenosis

o Coarctation of Aorta

o Mitral Stenosis

o Pulmonary Stenosis

acquired lesions

cause volume overload on heart

Examples:

o Aortic regurgitation

o Mitral regurgitation

o Tricuspid regurgitation

o Pulmonary regurgitation

*NOTE: physiology of obstructive

and regurgitant lesions is NOT req'd

*NOTE: most patients with cyanotic heart disease have R to L shunt, but they may

have a combined shunt (R to L & L to R) with complete mixing of blood in the heart.


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*REMEMBER:

Pulmonary blood flow: amount

of blood going to the lungs

Systemic blood flow:amountof blood going to the body

Left to Right Shunts------- Outflow Obstruction

There are 3 major types of L to R Shunts

1) ASD(atrial septal defect)

2) VSD(ventricular septal defect)3) PDA(patent ductus arteriosus)

In L to R shunts, the red blood crosses the area of the defect and goes to the

lungs. Whether the lesion is an ASD, VSD, or PDA, the blood goes across the

defect RA RV pulmonary artery lungs. This is an example of

"ineffective circulation"(amount of red blood going to the lungs = ineffective

pulmonary blood flow) because the blood is already 100% saturated and

canNOT become more red. It causes volume overload on the lungs, but there is

NO cyanosis because the systemic blood flow is still 100% saturated.

*NOTE: effective pulmon.blood flow: blue(cyanotic) blood going to lungs (what we need)

To measure the L to R shunt, we depend on the ratio between the pulmonary andsystemic blood flow (Q=blood flow). For example, if the ratio of Qp/Qs= 2:1

then the shunt is causing twice as much blood to pass through the lungs as what

is passing through the systemic arteries.

Physiologic effect of the shunt is dependent on 3 factors:

1) Location of the shunt

2) Size of the defect

3) Relative pulmonary and systemic vascular resistance (or ventricular

compliance in case of atrial level shunts)

FROMRO2IA

Large shunts cause the pulmonary blood flow to increase and can be associated later

with development of pulmonary arteriolar hypertrophy, increase in pulmonary

resistance and pulmonary hypertension. Over time the elevated pulmonary resistance

may force the direction of original shunt to reverse, causing R to L shunt and cyanosis.

The development of pulmonary vascular disease as result of chronic left to right shunt

is known as EISENMENGER Syndrome

ASD (v. imp)ASD is an atrial level shunt (persistent opening of interaterial septum after

birth that allows direct communication between the LA and

RA). The defect can occur anywhere along the septum and

produce different types of ASD that share the same

physiology (ex. secundum ASD, primum ASD NOT req'd).

VERY IMP: In CHD,

the heart will do what

it can to compensate

for and maintain CO.


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PhysiologyWe will focus on the physiology (v. imp) of ASD because it will help us

understand everything else heart changes, clinical signs and symptoms, and lab

findings. The CO in patients with ASD is normal, meaning the heart will pump

the same volume of blood to the body as a normal heart (normal CO= 3-5 L/min).

In the figure, the CO 4 L (volume of blood

leaving the heart) and the O2saturation = 100%.

It will return to the systemic veins as 4 L. Let's

assume that the ASD (between the LA and RA)

will allow another 4 L of blood to cross per minute

(from high pressure of LA to low pressure of RA).

So, we will have 8 L in the RA and RV. This volume

will go to the lungs and will come back to the LA

as 8L. Then it will be divided into 4 L across theASD and 4 L into the LV (which is the normal CO).

So at the equilibrium state, there is compensated

CO in patients with ASD. This means L to R shunt

does NOT compromise the systemic blood flow,

but it increases the pulmonary blood flow.

FROM RO2IA

In the RA 1/2 of blood is arterial with 100% O2sat. and 1/2 of blood is venous with

70% O2sat.. They will mix and the RV out put will be 8L blood with 85% O2saturation.

Based on the above, the following heart chambers undergo changes:1) LA dilation(it becomes bigger): because it is receiving 8 L of blood

instead of 4 L (twice the normal amount)

2) RA dilation

3) RV dilation

4) Pulmonary artery dilation

These areas are receiving more blood than usual, so they are subjected to

volume overload. Volume overload gives dilation in chambers and stenosis on

valves(tricuspid and pulmonary valves = stenotic due to chronic shunting and

volume overload). The majority of the shunt occurs during diastole(ventricular filling ventricular diastole = atrial systole)

The LV in patients with ASD is NOT affected, so there is NO LV dilation. This

means they will NOT develop signs of heart failure or decreased tissue

perfusion. They will NOT have any type of holosystolic murmur because the

flow across the ASD is at low pressure.


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Symptoms1) Usually there are NO symptoms (asymptomatic)

2) Some patients who present with FTT (failure to thrive) are incidentally

found to have ASD, but we should look for other causes of FTT because

ASD does NOT normally cause FTT.3) ASD aggravates symptoms of pulmonary diseases (ex. asthma, pneumonia,

etc) but does NOT cause them. So, children with underlying pulmon. dis.

may be more symptomatic with ASD due to increased pulmon. blood flow.

4) There is NO congestive heart failure (very rare)

5) Older children may complain of dyspnea on exertion only due to increased

pulmonary blood flow (asymptomatic at rest).

6) Pulmonary hypertension almost never happens in young patients with ASD

because it is a low pressure shunt (less than 10% risk)

7) Older patients may present with arrhythmias like SVT (supraventricular

tachy) or atrial/vent. tachy due to RA dilation.8) Paradoxical emboli may occur in older patients (rare in children).

FROM RO2IA: A paradoxical embolus is a venous embolus that bypasses the lung due to

R-L shunt through ASD, and becomes arterial embolus. It occurs with reversal of the

shunt in EISENMENGER syndrome.

Examination1) Normal in young infants

2) Prominent RV heave due to RV dilation

3) Wide, fixed split of S2 because the RV is pumping twice as much blood tothe lungs across the pulmon. valve. So, systole will occur over a longer

period of time and P2 will happen later than A2 of second heart sound.

4) Ejection systolic murmur of the pulmonary valve because there is more

blood across a normal valve (relative pulmonary stenosis)

5) Diastolic murmur (rumble) of the tricuspid valve (if the ASD is very large,

due to increased blood flow thru the tricuspid valve)

REMEMBER:

All findings and changes can be

explained byphysiology of ASD.


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DiagnosisECG:(beyond infancy - findings reflect the physiology)

1) Signs of right axis deviation

2) Signs of RA dilation or hypertrophy

3)Signs of RV increased mass (the ventricular mass is increased, NOTnecessarily hypertrophic)

4) Atrial arrhythmias +other things in specific types (not mentioned by dr

rSR pattern of incomplete right bundle branch block, peaked P waves in

lead II, sinus node dysfunction in sinus venosus defects,

northwest/superior QRS axis is typical of Primum ASD& AV canal defect)

CXR:

1) Normal (most of the time)

2) Dilated RA, RV & pulmonary artery: RA or right

border of the heart is dilated and extends more to

the right (NO shifting of apex beat)3) RV against sternum because it's dilated (lateral CXR)

4) Increased pulmonary blood flow (plethoric lungs)

5) Increased vascular markings (blood vessels are a

little larger than normal. The lungs are NOT opaque

and there is NO pulmon. edema. Actually, the lungs are

"plethoric" opp. of "oligemic lungs", which are more black)

6) Cardiomegaly (occasionally, because there is mainly RA

dilation NOT LV dilation)

Echocardiograph: Diagnostic method

Management1) The only method is closure of the defect, if it is indicated (by surgery or

by cathether details of devices used for closure NOT req'd)not mentioned by dr: Secundum ASD: transcatheter closure is

amenable in most cases. Sinus venosus, primum ASD and extremely large

or deficient rim secundum ASDs require surgical closure

2) NO medications should be given

3) NO need for subacute bacterial endocarditis (SBE) prophylaxis (not

mentioned by dr except in case of primum ASD because of theassociated mitral regurgitation)

4) NO restriction from activity

5) Spontaneous closure may occur in small or med. size secundum ASD

Dr. Zuhdi:There is increased risk of SBE because with time the shunt damages the

epithelium (breaks it down), which creates a good media for bacterial growth.


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VSDVSD is a communication between the LV and RV (ventricular level L to R shunt).

So we have red blood going to the RV. The types of VSD differ in terms of

management and prognosis, but they share the same physiology. VSD is

categorized into groups according to the site of the defect:

1) *Peri-membranous VSD(most common): co-ventricular defect around the

membranous part of the ventricular septum (remember that the

ventricular septum is mostly muscular, except for a small membranous

part underneath the aortic valve). There is incidence of aortic valve

prolapse and AI (aortic insufficiency)

2) Muscular VSD(2ndmost common): one or

more ms defects in any part of vent.

septum (anterior, apical, mid, posterior)

3) Inlet VSD or AV canal(more than aVSD): atrioventricular canal defect,

also known as "endocardial

cushion" defect. This defect is

associated with abnormal mitral and

tricuspid valves. Instead of

being 2 valves, they are actually 1

valve (common junction). Complete

AV canal is common in patients with

trisomy 21 or Down synd.)

4) Sub-pulmonary defect(conal septalhypoplasia) NOT req'd

Physiology

Remember the general rule: the heart will do whatever it canto make the CO normal. Again, we will assume that the CO

4 L min (same #s used in ex. for ASD). These 4 L will come

back to the RA RV, then another 4L it will cross the VSD

from LV to RV pulmonary arteryLALV. The ratio

between pulmon. blood flow and systemic blood flow (Qp: Qs)

is the same as that discussed above in ASD (2: 1, volume

overload), but the physio differs.

RV aspect of

vent. septumTricuspid

valve

Pulmonary

valve

RV

Aortic

valve

(inside)


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VERY IMPORTANT:

VSD systolic shunt

ASD diastolic shunt

Volume overload- dilation of

chambers & stenosis of valves

Pressure overload

hypertrophy of chambers

The chambers that will be affected in VSD:

1) LA dilationbecause it is receiving 8 L blood

2) LV dilationbecause it is receiving 8 L during

diastole (it fills with 8 L).

3) RV hypertrophydue to pressure load (there

is a hole between 2chambers, one pumping athigh resistance and the other pumping at low

resistance; so pressure will be transmitted to RV thru systole VSD

shunt is systolic. The RV will not be affected by any volume changes

because the pulmon. valve is open, so all of the 4L will go directly to lungs)

4) Pulmonary artery dilationbecause it is receiving more blood (like in ASD)

NO changes in RA (at least early on) and CO well maintained even in large VSDs

FROM RO2IA

The hemodynamic changes that occur in VSD depend on the size of defect and relative

resistance in pulmon. and systemic vasculature. In small VSD, the defect itself offersmore resistance to flow than pulmonary or systemic vasculature, thus the magnitude of

shunt depends on the hole. Conversely with larger defects, the volume of shunt

depends on systemic and pulmonary resistances. Remember that in the perinatal period

the pulmonary vascular resistance is approximately equal to the systemic resistance, so

minimal shunting occurs between the ventricles. However, after birth the pulmonary

resistance falls and the blood will be shunted to the right along the pressure gradient.

Symptoms

1) Newborns with VSD are usually well (asymptomatic, especially if smallVSD) because their pulmonary vascular resistance is high (right side of

heart receives all systemic venous return, including blood from placenta).

It takes about 4-8 wks for their pulmonary resistance to decrease to the

normal adult level. So, the L to R shunt is minimal in the newborn period.

FROM Illust.Text: With the first breaths the baby takes upon delivery, resistance to

pulmonary blood flow falls and the volume of blood flowing through the lungs increases

6-fold. This results in a rise in the LA pressure. Meanwhile, the volume of blood

returning to the RA falls as the placenta is excluded from the circulation. The change

in the pressure difference causes the flap of the valve of the foramen ovale to be

closed. The ductus arteriosus also normally closes within the first few hours or days).

2) Moderate to large VSD: LA/LV dilation due to increased pulmonary blood

flow. Unlike ASD, congestive heart failure may follow (according to the

Frank-Starling law, excessive dilation of the LV will cause it to lose its

contractility. So, there will be systolic

dysfunction, the patient will become

decompensated, and the CO will drop).

Dr. Zuhdi:

Large VSD > 50% aortic width

Small VSD = 1-3 mm

Moderate VSD = in between


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3) Symptoms of heart failure in infants or babies are different than those

seen in adults. Usually, infants with large VSD present with *respiratory

symptoms due to fluid accumulation in the lungs (v.imp) For example:

tachypnea, tachycardia, diaphoresis (sweating during feeding), decreased

or difficulty feeding, resp.distress, failure to gain wt, recurrent LRTI,etc

4) FTT, usually due to large VSD5) Compensated patients deteriorate rapidly with infection

FROM RO2IA:

Augmented pulmonary

circulation can cause

pulmonary vascular

diseases early in life. As

pulmonary resistance

increases the shunt may

reverse leading tohypoxemia & cyanosis

EISENMENGER'S

SYNDROME

Examination1) Newborns may NOT have heart murmur in the first day of life because

the pressure in both ventricles is almost equal (high pulmonary vascular

resistance). So, there is NO turbulence of blood across the VSD,

meaning NO murmur may be heard until about 4-8 wks of life (Dr. Zuhdi:

musical grade 2 ejection systolic murmur).

2) Displaced apex beat because the LV is dilated.

3) Hyperdynamic precordium with large, visible pulsations (Dr. Zuhdi)

4) Pansystolic (holosystolic) murmur is common after first day of life due to

blood flow across VSD. (Dr. Zuhdi: may be accompanied by palpable thrill)

5) Small muscular VSD may be associated with short systolic murmurs

(These murmurs are actually pansystolic, but we don't label them as such

because they stop before S2. This occurs because the defect is in the

muscular part of the ventricular septum; the VSD is initially open but

then closes upon itself during ventricular contraction. This is a good sign

because it means that the defect is getting smaller in size, so at onepoint the murmur will disappear).

6) Loud P2 of second heart sound (because there is pulmonary hypertension).

7) Diastolic rumble due to excessive flow across a normal mitral valve

(Dr. Zuhdi: diastolic murmur at the apex usually indicates a large VSD)

8) S3 gallop may be present in patients with heart failure.

9) Hepatomegaly due to liver congestion if patient develops right heart

failure (Dr. Zuhdi)


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DiagnosisECG:(beyond infancyonly helpful in dx. NL if small VSDDr. Zuhdi)

1) Signs of left axis deviation

2) Signs of LV hypertrophy (LV dilation is a more accurate description)

3)Signs of LA dilation4) Northwest (superior) axis in AV canal defects (not mentioned by dr)

*NOTE: ECG does NOT differentiate between hypertrophy and dilation (reflects

presence of ventricular mass in general)

Dr. Zuhdi:ECG in VSD changes with time. First, it shows signs of LV hypertrophy,

then signs of biventricular hypertrophy, and finally signs of RV hypertrophy depending

on which chambers are exposed to the highest blood load and pressure.

CXR:(NL if small VSD Dr. Zuhdi)

1) Increased pulmonary flow2) Increased vascular markings

3) Cardiomegaly (especially if large VSD)

Echocardiography(diagnostic): It diagnoses

presence and type of VSD, as well as its effect on

other cardiac structures.

Management

1)

Asymptomatic patients do NOT need any treatment (we just wait for theVSD to close spontaneously. Spontaneous closure is common in small and

moderate perimembranous and muscular defects

2) Symptomatic patients may need medications to alleviate symptoms

3) NO restriction from activity

4) NO SBE prophylaxis (according to the new guidelines). However, some

people still give SBE prophylaxis while others do NOT.

5) Surgical treatment is the standard treatment for symptomatic VSDs like

the AV canal type VSDs because they dont close spontaneously (details

NOT req'd). If Eisenmenger syndrome occurs, then surgery is

contraindicated (Dr. Zuhdi)6) Transcatheter closure of certain types of VSD has been done (not

mentioned by the dr)

Dr. Zuhdi:It is known that the most common CHD is VSD. However, recent studies

show that bicuspid aortic valve is now #1.


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Patent Ductus Arteriosus (PDA)PhysiologyPDA is a L to R shunt between

the aorta and pulmon. artery.

If we apply same #s used in

the above examples to PDA, we will

find that it is very similar to VSD.

It causes the same chamber

changes, but it differs in that it

also causes wide pulse pressure.

Symptoms(book & dr's slides)1) Usually present in first 2wks of life, when PDA starts to constrict

2) Signs and symptoms of decreased systemic perfusion3) Lethargy, and signs of CHF

4) Metabolic acidosis and shock develops quickly

5) Should be in the differential diagnosis of neonates with R/O sepsis

Examination1) Continuous murmur beneath

the left clavicle

2) Poor pulses collapsing or

bounding(wide pulse pressure)

3) Poor capillary refill4) May not detect radiofemoral

delay or BP gradient in

patients with COA

(coarctation of aorta)

5) Ejection systolic murmur may

indicate aortic stenosis

6) Tachycardia and gallop

7) Tachypnea

8) Hepatomegaly

DiagnosisECG: RV hypertrophy

Echocardiography: Final diagnosis

Management

CXR: (like VSD)

1) Cardiomegaly

2) Pulmonary edema

In infants with asymp. PDA, closure at about 1 yr of age is recommended to

abolish the lifelong risk of SBE.


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Coarctation of the Aorta

PhysiologyCoarctation is a non-shunt,

obstructive lesion (coarctation= constriction or pinching).

There is obstruction in the

distal part of aortic arch (just

distal to subclavian artery), which

will cause the heart to pump at a

higher pressure in order to perfuse

the lower extremities. Eventually,

there will be collateral blood flow across area of obstruction.

Symptoms1) Symptoms usually do not show at birth, they begin to emerge after 1 wk

2) Hypertension in the upper extremities (above the constriction)

3) Normal or low blood pressure in the lower extremities

Examination1) LV hypertrophy with dilation of apex beat.

2) Difference in blood pressure between upper and lower limbs (look above)

3) Normal or ejection systolic murmur between shoulder blades

DiagnosisECG: LV hypertrophy

CXR: 1) Usually normal

2) Rib notching from development of collaterals

ManagementA child with severe coarctation should have surgery in early childhood, after

which long-term follow up is necessary.


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Please note that info found inthis box is from the slides but not

mentioned by the doctor!

Cyanosis is a clinical sign where you have bluish discoloration of the

lips it happens when there is clinically significant amount of

deoxyhemoglobin , in order to see the cyanosis by your eyes theremust be 3-4 gm/dL of deoxyHb If the Hb in an individual is 15

needs 5 gm of deoxygenated Hb so the saturation should be less

than 70% in order too see cyanosis on the other hand desaturation is not a

clinical sign; cant be seen by your eyes but by the saturation that you measure ,

so not everyone who is hypoxic , will be cyanotic especially in children who

usually have Hb of 10 & need to 60% desaturated inn order to see the cyanosis.

Causes of cyanosis

In children the majority of causes are pulmonary causes , either

1. airway disease like pneumonia , asthma or foreign body due to preventing the

air from getting in or hypoventilation due to central causes.

2.intrapulmonary shunting; the blue blood passes to the red blood area.

Cardiac causes are always secondary to intracardiac shunting ; the blue blood

goes to the red blood area.

3. other rare causes.

Mechanisms of cardiac cyanosis1. Pure right to left shunt; so a portion of the blue blood going to the left

side of circulation, this what happened in a patient with Tetralogy Of

Fallot (TOF).

2. Mixing, meaning that blue blood & red blood are mixed together in a

chamber & then it is distributed to the lungs & body .

From Illustrated : Cyanosis in a newborn infant with respiratory distress (respiratory rate

>60 breaths/min) may be due to:

cardiac disorders - cyanotic congenital heart disease

respiratory disorders, e.g. surfactant deficiency, meconium aspiration, pulmonary

hypoplasia, etc.

persistent pulmonary hypertension of the newborn (PPHN) - failure of the pulmonary

vascular resistance to fall after birth

infection - septicaemia, group B streptococcus and other organisms

inborn error of metabolism - metabolic acidosis and shock

polycythaemia.


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=Note = the difference between them is that the 1stmechanism has only

rightleft shunt , while the 2ndone has rightleft & left right shunt

but still causes cyanotic heart disease.

3. The Recirculation; the whole red blood will go to the wrong side of

circulation ( to the pulmonary artery , & the whole blue blood will go tothe body. That happens in transposition; where the left ventricle is

pumping the blood into the lungs while the right ventricle is pumping to

the body. So the pulmonary arterial saturation is 100% , systemic arterial

saturation is 50%.

Approach to cyanotic baby

o detailed History; age at presentation can give you a hint about what the

pt has . ex. TGA may present in the 1

st

day of life, TOF appears in the 1

st

few months of life. Symptoms of presentation that might range from

pure cyanosis with no respiratory symptoms to heart failure symptoms

which is mostly respiratory symptoms; SOB, tachypnia, fever, FTT,

feeding problems

o physical examinationmight also help : - General Exam

-Vital signs - Lung exam - Cardiac exam.

o Testing ; many tests can be done to a cyanotic baby :

- Chest radiography

- Electrocardiogram non of the 3 is diagnostic of the lesion itself

- Hyperoxia test=Note= The only test that is diagnostic is Echocardiogram.

HYPEROXIA TESTvery important clinical test

- If the pt is cyanotic & you can overcome his cyanosis by giving him

O2 then more likely he has respiratory illness rather than a shunt.

If there is a shunt, means blue blood going to the body so it won't be corrected

by O2 .

- We give the pt 100% O2 for 15 min. then take arterial sample for ABG then

look at the partial pressure of O2 (PO2) .

PO2 is > 250 so more likely to be a pulmonary disease; overcome by O2

PO2 is < 150 so more likely to be a shunt ; cardiac

PO2 is 150-250 gray zone

=Note= if a pt has PO2 =150 the saturation is 100% so we dont depend on

saturation BUT depend on PO2


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CCYYAANNOOTTIICCHHEEAARRTTDDIISSEEAASSEESS55TTSSTetralogy Of Fallot ( the most common) = Rt-Lt shunt

Transposition Of Great Arteries = recirculation

Truncus Arteriosus = mixing

Tricuspid Atresia >> note it is Atresia not Tricuspid stenosis = mixing

Total Anomalous Pulmonary venous Return =mixing

=Note= some add 1P which is Pulmonary atresia that can comes alone.

TTEETTRRAALLOOGGYYOOFFFFAALLLLOOTT4 things

1.Pulmonary stenosis or right

ventricular outflow tract (RVOT)

obstruction.

2.VSD.

3.Overriding of aorta; looks like

arising from both RV & LV.(overridingmeans that it is deviated towards the rightside to ride over the VSD and the right

ventricle).

4.RV hypertrophy because VSD is

large so the RV has the same pressure as the LV.TOF is the most commoncyanotic heart disease & the 3rdmost common

congenital heart disease = 10% of CHD.

* In the extreme form there is complete pulmonary atresia (PA/VSD), 2% of

CHD.

There is no known etiology but it is more common in syndromes like Down

syndromepatients that usually have AV canal but may have TOF.

It might be seen in other syndromes but are not important to know.

* Not typically found with syndromes: De Lange, Goldenhar, Klippel-Feil

* TOF is seen with malformation assoc :VACTERL, CHARGE, Velo-cardio-facial.
http://radiologygeek.files.wordpress.com/2009/02/image8.pnghttp://radiologygeek.files.wordpress.com/2009/02/image8.png


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Key

TGA: Transpositoin of Great arteriesLA,RA: Lt & Rt Atrium

RV,LV : right & left ventricles

TOF : Tetralogy of FallotCO: cardiac output

ABG : Arterial Blood GasPDA : patent ductus arteriosusVSD : ventricular septal defect

SVC : superior vena cavaIVC : inferior vena cava

SVR: systemic vascular resistance

PVR: pulmonary vascular resistance

This Figureexplains everything , please concentrate & you will get the pictureeasily>> remember the 4 items of TOF

The cardiac output (CO) is well preserved, the

aortic outflow is about 4L/min so there is normalCO this 5 (in the figure) or 4L will come to the RA

then 2L will cross the ventricular septum & 3L will

go to the lungs, the reason why the RV is trying

to pump blood & there are 2 ways to go either

through the pulmonary artery or the VSD

(remember that there is obstruction near the

pulmonary valve "RVOT obstruction" so some

blood will go through VSD but if no obstruction,

all blood will go through pulmonary artery & not

only That, some blood from LV will pass VSD topulmonary artery , so what determines how much

blood crosses is actually THE RESISTANCEto the

flow, there is much resistance to the flow to the

pulmonary artery so some of the blood will cross the left side of the circulation

so we have Right Left shunt.

The 3 L goes to the lungs , will come back fully saturated 100% to the LV ,

3L"from lungs"(100%) + 2L"fromVSD"(50%) =5L"goes thro aorta"(80%), the

pt will be cyanotic because of Right Left shuntso the saturation might be

80% goes through aorta then will come back from body as 50% saturation in the

RV 2L to left & 3L up! Blood to LA will be 100% 3L(100%) +

2L(50%)=etc.

>> Now we will conclude the chambers affected in TOF>>

~ None of chambers will have volume overload so NO Cardiomegaly, normal size

of the heart.

~ Decreased pulmon. blood flow so in X-ray you

will see oligemic lungs or more black lungs.

~ RV Hypertrophy because VSD is large so the

pressure is transmitted from the LV to the RVso there might be RV heave & right axis

deviation.

=Note= to differentiate between:

- oligemic lungs : normal # of ribs + black lung

- Hyperinflated lungs : more ribs + black lung


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Physiology of TOF

Depends on 2 things:

1. large unrestrictive VSD( equal pressure in both sides) 2. pulmonary stenosis.

If the pt doesnt have pul. Stenosis so it is VSD so overriding of aorta doesnt

contribute to physiology & RV hypertrophy is just due to VSD.

Pulmonary stenosisdiffers from pt to another & it's progressive with time; at

1 month of age it is moderate , but at 6 months it is sever & more cyanotic with

time.

Flow depends on the difference between systemic & pulmonic outflow

resistance

From Ru2ia: Normally, PVR (pulmonary vascular resistance) is 1/10thof the systemic resistance(10 times lower), so in case of large VSD, 10 times the amount of blood will go tothe lungs compared to the body. This of course means an overload on thelungs' vascularity.

From Ru2ia: Exercise will rapidly drop the PaO2, how?? Decreased SVR Increased R->L shunt During exercise, the systemic vascular resistance (SVR) is

decreased, this means that instead of the RV pumping 3L to the lungs and 2L to body (through VSD), it willpump 1L to the lungs and 4L to body. This means less blood to the lungs less O2

Increased oxygen consumption decreased venous oxygen saturation (instead of 50%, u willhave 30% so when mixing with the 3L(100%) = less O2 sat).

>> Patients with TOF or other cyanotic heart dis. (whom are not treated) oftensuffer from :

With TOF, PVR is usually normal

Resistance to flow is related to the fixed and/or dynamicobstruction (or multiple levels of obstruction)

Symptoms depend on the relationship of SVR to this resistance

*If pulmonic obstruction is mildMinimal cyanosis

Good exercise tolerance*With increasing obstruction

Worsening cyanosis at rest

Higher risk of spellsPoor exercise tolerance*pH and PCO2 are normal at rest*PO2 will vary with degree of obstruction


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Hypercyanotic spell ( TET spells ) IMP

Mainly here we talk about SQUATTING; the pt squats when he

feels cyanotic (knee-chest position) it is seen in pts beyond age

of 1 year, they learn how to do this in periods when they haveexcessive/sever cyanosis which is life threatening.

Precipitated by activity or fright, BUT could be spontaneous.

Physiology of Squatting

Hypercyanosis happens because there is more RV outflow obstructions at

times when they become profoundly cyanotic, the mechanism is somewhere

around the obstruction; where they have hypovolemia if the pt slept all through

the night , fasting ;(SVR is low, and blood volume is low after sleep), he will

become agitated in the morning for any reason, he becomes tachycardiactachycardiawill impair ventricular filling ; because it happens at the expense of

DIASTOLE not systole so impairment in the RV filling so the obstruction to the

RVOT increases (becomes more profound) because of its dynamics just under

the valve, just like pts of

Hypertrophic obstructive cardiomyopathy>> they have less

volume in the ventricle so the obstruction becomes sever

when they stand up the murmur becomes louder because the

filling drops.

So the same thing with the RV because of depressed

/decreased RV filling there will be more obstruction to the

pulmonary outflowthe blood of right ventricle will cross

VSD to the LV so more Right to left shunt during those

times cyanosis feeling cyanotic will increase agitation

( ) more tachycardia So it becomes like a cycle: the

pt either dies or loses consciousness.

>> If he loses consciousnessless tachycardiamight regain consciousness.

Dr.Zuhdi: stress( hunger,trauma,..) might cause cyanotic spell , the pt becomes semiconscious , O2sat = 40-50% because of infundibular spasminc. Rt to Lt shunt

In the tt u can give propranolol to release the spasm, NaHCO3 bcoz of metabolic acidosis ( lacticacidosis) due to hypoxia & anaerobic glycolysis.

Treatment of Spells

Reverse elements of the cycle :

-- if cyanosed give O2 ; improves PO2 in the pulmonary venous blood

-- knee-chest position ,why?

::Summary::

Sleeping

stress

tachycardic

impaired RV

fillinginc. obstruxn

inc. R to L

shunt

cyanosis


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1.Because squatting will squeeze the liver so this will increase the venous return,

filling the RV ,decreasing the obstruction.

2. squatting kinks the femoral arteries so this increases the resistance in the

systemic circulation so blood would rather go to the lungs than the aorta

-- give Morphine to calm the pt down.

-- give fluids to open up RV to fill it.-- finally give systemic vasoconstrictor (phenylpherine) which works at the same

mechanism of kinking femoral artery; inc. SVR.

-- beta blockers if surgery is not available to prevent these events.

Symptoms of TOF

-Cyanosis.

-Periods of Squatting.

Dr. Zuhdi: 1. cyanosis at age 4-5 mo depends on severity of pul.StenosisWith age due to subvalvular, infundibular stenosis 2.clubbing 3.transient inc. in cyanosis 4.tachypnea.

From Ru2ia: Clinical features: Extreme variability of presentations

Related to degree of RVOT obstruction Consistency of symptoms relates to degree of shunting between right and left

Cyanosis might be present in the neonatal period, it is always present in patients with PA (pulmonaryatresia) or severe obstruction. If you listen to them you might not here a murmur, especially if the PDA islarge (the PDA would be the only route of blood to the lungs).

Cyanosis might be minimal if the obstruction is mild or not severe

Some patients would be asymptomatic but with a murmur. The murmur of TOF can't be missed as thepulmonary valve is right under the sternum and it is a loud murmur.

Cyanosis Typically appears after 1 month as the obstruction becomes more prominent (typically appears

between 6wks and 6 months in the unrepaired infant)

Parents complain from cyanosis of nail beds and mucous membranes May be present at rest or only with agitation/exercise

Persistent cyanosis in childhood and clubbing if not repaired

*Cyanosis will be accompanied by: Hyperpnea: Increased rate and depth of respirations Increased fussiness progressing to decreased level of consciousness Increasing acidosis, can be fatal

*Theories: Primary infundibular spasm (unlikely) Hyperpnea as a primary cause Circulating catecholamines

*Spells are an indication for need of surgical intervention


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Diagnostic studies

CXR >>

~ normal size BUT abnormal shape

(boot-shaped heart)

~Upturning of the apex~Concavity on the area of pulmonary artery.

Instead of convexity there is concavity

because the pulmonary artery is small.

~Lungs are oligemic.

EKG >>

~RV Hypertrophyis the characteristic

finding

~RA Dilatation ~Right axis deviation.Dr. Zuhdi: on examination you can hear Ejection

Systolic Murmur bcoz LV & RV both pump to aortaso heard sound asso. With pul. stenosis (inc. intensityinc. severity of pul.stenosis), PMI= pul. Area.

*Arrhythmias and ectopy are uncommon pre-operatively

*RAD - degree of axis deviation relates to severity of RVH

Medical management

Polycythemia

Most pts of TOF are polycythemic as a secondary mechanism to the Hypoxia.Hematocrit will be > 60% so might have symptoms of hyperviscosity syndrome.

* > 65% serious hyperviscosity risk - Neurologic sequelae

-Clotting abnormalities

* Consider phlebotomy pre-operatively

Infection

R->L shunt, direct route to body

Bacterial endocarditis

Brain abscessTET spells

As mentioned above & MSO4, surgery

Surgical management

1.VSD closure
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transatrial access if possible

Infundibular resection for visualization

Patch closure

2.Alleviation of RVOT obstruction done by surgery.

Infundibular resection vs. transannular patch

TRANSPOSITION OF GREAT ARTERIES (TGA)

~The pulmonary artery coming from the LV while the aortic artery fromRVso

blue blood will go to the same area & the red blood to the same area.

~We should have some mixing in order for pt to

survive ; because he won't survive more than few minutes if no communication .

~The communication has to be at the atria level(PFO or ASD) BUT if they dont have we should create it.

~ 50 % of pts have VSD; usually small, not contributing to the physiology.

~ usually presents in the 1st day/hrs of life with cyanosis so we dont think of

TOF although it's the most common.

~ More common in boys.

Diagnosis

If left untreated then the CXR finding will be

prominent.

-Egg on side - Narrow mediastinum;

because pul. Artery & aorta are front & back

NOT side by side.

=Note= you can't find that in the newborn period

but later on.

Physiology

The pt presents with profound cyanosis at birth; we should do number of things

medically before he goes to surgery; one is to insure there is mixingat atrial

level & to insure that blue blood is going to lungsso what we do is to keep PDA

open because it will allow blood to go from aorta to pulmonary arterywhich is blue

as it comes from Aorta that is connected to RV.
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* Examis significant for Single S2

Ejection click of the abnormal truncal valve Systolic murmur of truncal valve stenosis if present Diaastolic murmur of truncal valve insufficiency

Gallop* CXR: Cardiomegally , increased pulmonary circulation

* Management: basically the management is surgery like TOF, so we close the VSDand separate the Aorta and the Pulmonary artery.

TTRRUUNNCCUUSSAARRTTEERRIIOOSSUUSS

Is a common trunk arising from both

ventricles so it implies that there isVSD. There is no truncus without VSD

but we dont call it VSD or truncus-VSD.

This common trunk is divided into the

pulmonary artery & the Aorta , it

differs from the others because the

red & the blue blood are mixed

together .

It will be divided into 2 circulations

both have the same color ; same O2 saturation so it's complete mixing.

Then the blood will pass according to the resistance ; pulmonary vascularresistance (PVR) is very low (large way) BUT the systemic vascular resistance is

very high (small way) so more blood to the lungs.

Pts of TA won't present with cyanosis BUT they will present with Heart

Failure!! .why?Because there is more blood to the lungs; the ratio between pul. & systemic

blood flow is more than (5 : 1) so there will be dilation of the LA & LV &

symptoms of Heart failure .

with time they become cyanotic because of PVR rising as in Pulmonary

Hypertension.

Although it is called cyanotic heart disease BUT it causes Heart Failure

(tachypnea, hepatomegaly, FTT).


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TRICUSPID ATRESIA

Atresiameans The valve didnt form so NO

communication between RA & RV.

They have to have atrial communication.We have 2 options : either we will have VSD

because blood in the RA will mix with the blood in

the LA complete mixing so you can see it purple in

color in the figure . blood going to the lungs can

come from 2 options either VSD to the pul. Artery

or across Patent Ductus Arteriosus (PDA) to pul.

Artery .

Symptoms will depend on the amount of Pul. Blood

Flow ;

if VSD is small there will be cyanosisif VSD is large there will be Heart Failure because more blood flow to the

lungs than the body, so the cyanosis will be minimal .

=Note= So both Tricuspid Atresia + Truncus Arteriosus will have HFsymptoms.

TOTAL ANOMALOUS PULMONARY VENOUS RETURN (TAPVR)

It is the rarest cyanotic heart disease.

Instead of pulmonary veins coming to LA , they miss the LA but will come to RA

through a communication either through an abnormal vein ( vertical vein ordirectly to RA so the pul.veins which have red blood is coming to the SVC to RA

or to INC to RA so all the blood will be mixed in the RA (complete mixing), the

blood can't go to the LV except through ASD or

PDA.

The blood will be distributed to both circulations

through ASD & the pt is cyanotic.

Types of (TAPVR)

>> Supracardiac through the SVC

-Figure above-

>> Infracardiacthrough the IVC

-figure below-

>> Mixed type.From Ru2ia:In a radiograph of a Pt with supracardiacTAPVR, you will see a dilated superior vena cava, and it wouldshow a characteristic figure 8 shape.While in the infracardia type you would see pulmonary edemawithout cardiomegally, unlike in CHF where the heart would belarge.


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~ SLIDES NOT MENTIONED BY THE DOCTOR ~


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Done by Ruba Al-Abwah & We'am Al-Zayadneh

www.shifa2006.com

REFERENCES:Lecture recording

Ro2ia lecture

Illustrated Textbook of Pediatrics

Dr. Zuhdi Al-Hanuti (Al-Mafraq Hospital)

Cyanotic and Acyonitic Heart Diseases

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Transcript of Cyanotic and Acyonitic Heart Diseases