CONGENITAL HEART DISEASES (CHD)

Dr. Emmanuel RUSINGIZA

Objectives

Understand the fetal circulation and changes that occur at birth

Understand the basic pathophysiology and the clinical presentation and of common CHD

Suggest the appropriate management of common CHD in children

OUTLINE

1. FETAL & PERINATAL CIRCULATION

2. COMMON MALFORMATIONS & SYNDROMES WITH CARDIOVASCULAR INVOLVEMENT. 3. ACYANOTIC HEART DISEASES

3.1 VENTRICULAR SEPTAL DEFECT 3.2 ATRIAL SEPTAL DEFECT

3.3 ATRIOVENTRICULAR SEPTAL DEFECT

3.4 PATENT DUCTUS ARTERIOSUS

Outline…

4. COARCTATION OF AORTA

5. PULMONARY VALVULAR STENOSIS

6. CYANOTIC CONGENITAL HEART DISEASES

6.1 TETRALOGY OF FALLOT

6.2 D-TRANSPOSITION OF GREAT ARTERIES

6.3 OTHER CYANOTIC HEART DEFECTS

FETAL CIRCULATION

Is integral part of understanding pathophysiology, clinical manifestations and natural history of CHD

Arranged in parallel, Exchange of gases and nutrients in placenta, has

the lowest vascular resistances in the fetus RV delivering the majority of its output to the

placenta for oxygenation, LV : heart, brain, and upper part of the body.

This parallel circulation permits fetal survival despite a wide variety of complex cardiac lesions.

Fetal circulation…

Blood returning from the placenta via the umbilical vein;

Some of it: into the hepatic veins and the portal system of the liver, whereas the remainder passes through the ductus venous into the inferior vena cava.

Fetal circulation…

About 40% of the blood returning from the inferior vena cava passes across the foramen ovale into the left atrium;

Pulmonary arteries: High resistance due to fluid –filled lungs and constricted pulmonary arterioles.

Almost 90% of pulmonary flow, passes through the open ductus arteriosus into the low-resistance descending aorta and placenta

Transitional circulation at birth

>>> Circulation from parallel to serial (gas exchange in the lungs). Failure of any one of complex series that take place within minutes

of birth leads to generalized hypoxemia and brain damage or death.

Removal of the placenta results:

Incre a s ing o f s y s te m ic re s is ta nc e

Cessation of blood flow in the umbilical vein, closure of ductus venosus

Re duc tio n in the p ulm o na ry va s cula r re s is ta nc e

Functional closure of the foramen ovale

Closure of ductus arterious

Incre a s ing o f s y s te m ic flo w

Chro m o s o m a l s yndro m e s Chro m o s o m a l Syndro m e s (fre q ue nc e o f he a rt m a lfo rm a tio ns )

He a rt d e fe c t

Down syndrome (50%) AV septal defect, VSD, ASD, PDA, TOF

Trisomy 18 (90%) VSD, ASD, AV septal defect, PDA

Trisomy 13 (90%) VSD, ASD, AV septal defect, unique ventricle

Trisomy 22(50%) VSD, ASD, PDA

G e ne tic a bno rm a litie s Syndro m e (lo c a lis a tio n) He a rt d e fe c t

Di George (22q11) Troncus arteriosus, TOF, inter of aortic arch

Holt-Oram(12q24) ASD

Noonan (12q) Pulmonary stenosis, ASD, cardiomyopathy

Williams Beuren (7q11.23) Supra-aortic stenosis

CHROMOSOMAL AND GENETIC ABNORMALITIES with Cardiac involvement

NON CYANOTIC CONGENITAL HEART DISEASES

1. VENTRICULAR SEPTAL DEFECT (VSD).

VENTRICULAR SEPTAL DEFECT .

  Dehiscence of interventricular septum

most common lesion seen in congenital heart diseases (30%).

Ventricular defect may be located anywhere in the ventricular septum,

may be single or multiple, and may be of variable size and shape.

Anatomic types of VSDs

muscular, (5-6) membranous, (1-2-3) Infundibular (7), sub-

aortic (8)

Endocardial cushion (4).

VSD…

Anatomy4 types of VSD according to their location:

• Me m bra no us d e fe c t: jonction tricuspid- aortic valves

• Mus cula r d e fe c t: may be located anywhere in the apical, mid, anterior, or posterior muscular septum and are often multiple.

VSD…

Infund ibula r d e fe c t: Located under the pulmonary valve when viewed from the right ventricle and are immediately beneath the aortic valve when viewed from the LV.

Endo c a rd ia l c us hio n d e fe c t: located beneath the tricuspid valve, extending to the tricuspid valve ring.

VSD…

Physiology• Size of the defect and the pulmonary vascular

resistance determine the hemodynamic: left to right shunting through the ventricular defect begins and increases in the first weeks of life.

• The bulk of shunting occurs in systole, with lesser amounts in diastole.

• Symptoms are determined by the size of the shunt: With a large effect, such heart failure can occur within days of birth, but is usually delayed until the third week of life.

VSD…

Symptoms:

• Tachypnea, sweating• Failure to thrive (poor caloric intake and increased oxygen

consumption due to excessive work of the heart and lungs).• Recurrent respiratory infections

Physical examination: depends up on amount of left to right shunting.

- Polypnea- Hyperdynamic impulse, rapid- Systolic murmur at low sternal border- Pulmonary crepitations are often due to infection or atelectasis

andno pulmonary oedema.- Liver enlargement

VSD…

Investigations:

Electrocradiogramo Normal in case of small VSDo Left ventricular hypertrophyo High right ventricular pression 

Chest X-ray:o Cardiomegalyo Increased pulmonary vascular marking

Echocardiography: Confirms the diagnosis  Cardiac catheterization

o Rarely necessary since arrival of echocardiography. o Used often to quantitate pulmonary vascular resistance and study resistance

responses to vasodilators.

Antenatal diagnosis: possible!!!

Pro g no s is & Co m p lic a tio ns

30-50 % of small VSDs will close spontaneously , most frequently during the 1st year of life

Majority of defects that close will do so before age 4 years

One of the long term risks for these patients is that of infe c tiv e e nd o c a rd itis .

It is less common for moderate or large VSD to close spontaneously , even defects large enough to result in H.F.(manifested in infants as F.T.T.) may become smaller & rarely will close completely.

Recurrent chest infections , C.H.F. and pulmonary hypertension in large defects leading to pulmonary vascular obstructive disease = EISENMENGER Syndrome.

Treatment (small defects)

- Reassure parents

- surgical repair is not recommended

- Protection against infective endocarditis

- Follow up screening for pulmonary HTN

Treatment (large defects)

Two aims : - control CHF

- prevent development of pulmonary vascular disease.

•Medical: Lasix and captopril

•Feeding (high calories)

•Surgical closure for large defects between 6 & 12 months of age.

2. ATRIAL SEPTAL DEFECT (ASD)

ATRIAL SEPTAL DEFECT

• 8% of congenital heart diseases.

• Anatomy and physiology:

o single or multiple. o Involves three structures: the septum primum, septum secundum

and atrioventricular canal septum

o The amount of shunting : left ventricular compliance.

o Although most infants with ASD are asymptomatic, a few numbers develop congestive heart failure and growth failure.

o Older patients may develop pulmonary vascular disease. In general, this is rare before 20 years.

ASD…

Clinical manifestations The lack of symptoms and the lack of readily heart

murmur account for the delay in discovering

A few small infants and many older adults present with congestive heart failure.

Physical examination:o Left parasternal bulge evidenceo Fixed splitting intervalo Ejection pulmonary systolic murmur, absent

occasionallyo Diastolic rumble at the left lower sternal border.

ASD…

1. Electrocardiography: Incomplete right bundle branch block RVH (rarely)

2. Chest X-Ray: Cardiomegaly proportionate to the amount of

shunting and the pulmonary vascularity.

ASD…

3. Echocardiography: confirms the diagnosis

Others exams:• Catheterization in case of doubt on abnormal

pulmonary veins, pulmonary hypertension and ASD closure.

• MRI: helpful in patient with a known or suspected ASD, usually adolescent and adult with inconclusive clinical and echocardiographic findings.

ASD…

Treatment: Medical treatment in case of congestive heart

failure, with diuretics;

Surgical repair or closure by device (Amplatzer…).

3. ATRIOVENTRICULAR SEPTAL DEFECTS (AVSD)

ATRIOVENTRICULAR SEPTAL DEFECTS

Abnormalities grouped together because they represent a spectrum of a basic embryologic abnormality:

a . Pa rtia l a trio ve ntric ula r s e p ta l d e fe c t ostium primum defect is situated in the lower

portion of the atrial septum and overlies the mitral and tricuspid valves.

cleft in the anterior leaflet of the mitral valve . The ventricular septum is intact.

b . Co m p le te AV s e p ta l d e fe c t, also known as an AV canal defect or an endocardial cushion defect: - Ostium primum defect - Absence of AV septum - ventricular septal defects with markedly abnormal AV valves.

The severity of the valve abnormalities varies considerably; in the complete form of AV septal defect, a s ing le a trio ve ntric ula r va lve is c o m m o n to both ventricles with a lateral leaflet in each ventricle.

AV septal defect

AV septal defect

common in children with Down syndrome

PathophysiologyPa rtia l a trio ve ntric ula r s e p ta l d e fe c t.

Basic abnormality: ostium primum and a left-to-right shunt across the atrial defect and mitral.

Shunt is usually moderate to large,

The degree of mitral insufficiency is generally mild to moderate,

Pulmonary arterial pressure is typically normal or only mildly increased.

>> The physiology is therefore similar to that of an ostium secundum ASD.

PathophysiologyCo m p le te a trio ve ntric ula r s e p ta l d e fe c t.

L-R shunt occurs at both the atrial and ventricular levels.

Additional shunting may occur directly from the left ventricle to the right atrium because of absence of the AV septum.

Pulmonary hypertension and an early tendency to increase pulmonary vascular resistance are common.

AV valvular insufficiency increases the volume load on one or both ventricles.

Some R-L shunting may also occur at both the atrial and ventricular levels and lead to mild arterial desaturation.

With time, progressive pulmonary vascular

disease increases the right-to-left shunt so that clinical cyanosis develops (Eisenmenger).

Clinic a l m a nife s ta tio ns .

Ostium primum defects: asymptomatic (anomaly is discovered during a general physical examination.

Moderate shunts and mild mitral insufficiency,

the physical signs are similar to those of the secundum ASD, but with an additional apical murmur caused by mitral insufficiency.

Clinical manifestation…

A following history may be abtained: exercise intolerance,

easy fatigability,

recurrent pneumonia especially in infants with large left-to-right shunts and severe mitral insufficiency.

Complete AV septal defects:

Heart failure and intercurrent pulmonary infection in infancy with minimal cyanosis.

Failure to thrive

Enlarged liver

Systolic murmur in the lower left sternal border.

2nd heart sound is widely split if the pulmonary flow is massive and a pulmonary systolic ejection murmur is produced by the large pulmonary flow.

Apical holosystolic murmur of mitral insufficiency may also be present.

>>> Pathophysiology Similar to large VSD

Diagnosis

Chest X-ray in complete AV septal defects often show:

- moderate to severe cardiac enlargement caused by the prominence of both ventricles and atria.

- large pulmonary artery and increased pulmonary vascularity.

Diagnosis…

ECG : - QRS axis with left axis deviation to the left

upper or right upper quadrant, - signs of biventricular hypertrophy or isolated

right ventricular hypertrophy, - right ventricular conduction delay (RSR′ pattern

in leads V3 and V1), - normal or tall P waves, and occasional

prolongation of the P-R interval .

Diagnosis…

Echocardiogram confirms the diagnosis

Cardiac catheterisation: rarely indicated

Treatment

Medical treatment as large VSD Surgical repair because of the risk of

pulmonary vascular obstructive disease developing as early as 6–12 mo of age,

Correction in infancy (3-6 months), Palliation with pulmonary arterial banding:

patients who have other associated lesions that make early corrective surgery too risky.

4. PATENT DUCTUS ARTERIOSUS

PATENT DUCTUS ARTERIOSUS

Etiologies: - Prematurity - Congenital rubella - Higher altitude

Anatomy

Ductus arteriosus connects the origin of the left main pulmonary to the aorta, just below the left subclavian artery.

The ductus closes through muscular constriction a few hours after birth.

Physiology

Excessive blood flow to the lungs, left atrium, left ventricle and ascending aorta with enlargement of this structures in proportion to the size of left-to-right shunt.

Clinical manifestations: L-R shunting

Tachypnea,

Dypnea with intercostals or subcostal retractions,

Hepatomegaly

growth failure

prominent arterial pulsations (present when large ductus arteriosus).

Investigations

EKG : shows LV hypetrophy

Chest X-Ray: cardiomegaly and enlargement of pulmonary vessels

Echocardiography: confirms the diagnosis

Investigations…

Cardiac catheterization: necessary in case of uncertain diagnostic and for studying pulmonary resistance response to vasodilatators (oxygen and nitric oxide).

Used also for transcutaneous closure by

devices

Ste nting o f na rro we d PDA to the p a tie nt p re s e nting s e ve re c ya no s is o n PAVSD.

Ductus arteriosus in premature Infants

  Fonctional closure of the ductus arteriosus

occurs in some 90% of full-term newborns within a couple of days.

In premature infants: ductus persists in many with those of clinical significance being more common in the smallest babies, with respiratory distress syndrome.

Maternal rubella is among etiologies of patent ductus arteriosus.

Treatment: Indomathacine or ibuprofen Surgical ligation or closure

 OTHER  L to R shunts

COARCTATION OF AORTA

Def: obstruction in the descending aorta located almost invariably at the insertion of the ductus arteriosus.

Represents about 6% of congenital heart diseases.

The diagnosis is essentially clinic, based on the absence or weakness of femoral pulse compared to humeral ones.

Coarctation of Aorta

Neonates with severe coarctation of the aorta may present very ill with sudden onset of heart failure within weeks of birth after closure of ductus arteriosus.

The frequent malformation in coarctation of aorta is Turner syndrome (20%).

Clinical manifestations

Signs of heart failure in case of severe coarctation (before the 14th day of life) with tachypnea, tachycardia, pulseless and acidosis.

Decreased or absence of femoral pulses, hypertension, decreased BP in lower limbs.

Sub-clavian systolic murmur irradiating to the back.

Investigations

Chest X-ray: normal in most of the cases

ECG: LV hypertrophy

Echocardiography: confirmation of the obstacle with Doppler and assessment of the LV contractility.

CT scan and RMI in big child

Management

A severe coarctation of aorta with signs of heart failure is a surgical emergency (Crafoord intervention).

PULMONARY VALVAR STENOSIS

Accounts for 7–10% of all congenital heart defects.

Pulmonary stenosis as a result of valve dysplasia is the most common cardiac abnormality in Noonan syndrome

Pathophysiology

The obstruction to outflow from RV to the pulmonary artery:

increased systolic pressure and wall stress, leads to hypertrophy of the RV

Severity of these abnormalities depends on the size of the restricted valve opening.

Clinical manifestations

moderate stenosis usually do not have any symptoms.

stenosis is severe, signs of right ventricular failure such as: Hepatomegaly ( with hepatojugular reflux in older

children) peripheral edema,

Clinical manifestations…

-   exercise intolerance may be present

- loud, long, and harsh systolic ejection murmur: usually accompanied by a thrill, is maximally audible in the pulmonic area

In a neonate or young infant with critical pulmonic stenosis, signs of RV failure may be more prominent, and cyanosis is often present because of shunting at the foramen ovale.

Investigations:

Electrocardiogram: RVH and tall P wave.

Radiography: cardiac enlargement. Prominence of the main pulmonary artery segment may be seen. Intrapulmonary vascularity is decreased.

Echocardiogram shows severe deformity of the pulmonary valve and right ventricular hypertrophy.

Cardiac catheterization for balloon valvuloplasty

procedure.

Treatment

Balloon valvuloplasty

Surgery intervention for Noonan syndrom (severily thickened valves)

CYANOTIC HEART DISEASES

TETRALOGY OF FALLOT

Cyanotic congenital heart malformation comprising: infundibular pulmonary stenosis,

conoventricular septal defect(VSD),

dextroposition of the aorta such the aortic root overrides the crest of the ventricular septum

RV hypertrophy.

Tetralogy of Fallot…

Most common cyanotic cardiac defect with an incidence of 3.26 per 10.000 live births.

Patients with TOF present sometimes chromosomal abnormalities (22q11.2 microdeletion).

Di Georges Syndrom

Physiology

Cyanosis due to R-L shunt at the ventricular level.

The volume of the ventricular R-L shunt, and hence the degree of cyanosis, is directly proportional to the severity of right ventricular outflow obstruction.

Pathophysiology…

Neonates with very mild obstruction of the infundibulum may have normal systemic arterial oxygen saturation and are said “pink tetralogy”.

There is a tendency in the TOF for subpulmonary obstruction, and hence cyanosis, to increase as the children grow.

Pathophysiology…

Dynamic factors may serve to further compromise pulmonary blood flow, increase R-L shunting, and worsen cyanosis in TOF.

Spasm of the sub-pulmonary infundibulum will have such effect, as will increase in pulmonary vascular resistance (crying) or decrease in systemic vascular resistance (exercise).

Catecholamine stimulation of RV mechano-receptors has also been postulated to increase R-L shunting = hyp e rc ya no tic s p e lls .

Clinical manifestations

Cyanosis (in function of the RV outflow obstruction, may be inapparent in neonate), increasing with growth.

Systolic ejection murmur of pulmonary stenosis

Chronic cyanosis is associated with clubbing fingers and toes, may also cause delayed physical growth and diminished cognitive function.

Hypercyanotic spells: hallmark of tetralogy of Fallot!

o In a typical spell, the child becomes distressed and inconsolable, without apparent reason, most often in the morning. Older children adopt “squatting” position to compensate the malaise.

o Crying is associated with progressively deeper cyanosis and hyperpnea,

o Auscultation during the spell reveals a notably diminished or even absent murmur.

o Not infrequently, the spell terminates with unconsciousness and, rarely, convulsions.

o If the hypoxemia is extreme, permanent neurologic sequelae and even death may occur.

Clinical manifestations…

Investigations

ECG: shows RVH and right axis deviation

Chest X-ray: normal heart size, decreased pulmonary vascularity. The apex of the heart is often elevated owing to RV hypertrophy with aspect «boot shape” or ”Coeur en sabot”.

Absence of thymus shadow in the newborn indicate associated DiGeorge syndrome.

Investigations…

Echocardiography: confirms the diagnosis and associated lesions.

Cardiac catheterization: limited indications in case of pulmonary atresia, abnormal coronary artery.

Complications

Cerebral thrombosis : common in extreme polycythemia and dehydration.

Brain abcess

Bacterial endocarditis

Management:

Preventive treatment: Iron to prevent microcytosis

Hypercyanotic spells: Position of infant on abdomen in a knee-chest position O2 Rehydration with colloid Morphine sulfate SC or IM only if a ventilator is

available Propranolol IV 0.1mg/kg slow Sodium bicarbonate 8.5% IV slow to correct acidosis Oral propranolol 0.5mg/kg 4 times/day for

maintenance.

Management…

Surgical repair between 3-6 months but indication if the patient presents hypercyanotic spells.

Rare newborns with critical RV outflow obstruction and inadequate aorto-pulmonary collaterals may be ductus arteriosus dependent and require prostaglandin E1 before a Blalock Taussig shunt.

Balock Taussig Shunt

D-TRANSPOSITION OF GREAT ARTERIES

D-TGA with an intact ventricular septum is also referred to as simple TGA or isolated TGA.

Before birth, oxygenation of the fetus is nearly normal,

After birth, once the ductus begins to close, blood via the FO usually insufficient and severe hypoxemia ensues, generally within the 1st few days of life.

CLINICAL MANIFESTATIONS

Cyanosis and tachypnea are most often recognized within the 1st hrs or days of life.

Hypoxemia is usually severe, but heart failure is less common.

Clinical manifestations…

Medical emergency, only early diagnosis and appropriate intervention can avert the development of prolonged severe hypoxemia and acidosis, which lead to death.

Physical findings associated with cyanosis may be nonspecific (no murmur).

Investigations.

ECG : neonatal right-sided dominant pattern.

Roentgenograms of the chest may show mild cardiomegaly, a narrow mediastinum (hence an “egg-shaped” heart, generally normal in early newborn.

Echocardiography confirms the transposed ventricular-arterial connections and associated lesions.

Cardiac catheterization: in patients who require emergency balloon atrial septostomy .

Treatment

Infusion of prostaglandin E1 to maintain patency of the ductus arteriosus and improve oxygenation

Rashkind balloon atrial septostomy.

Arterial switch (Jantene operation) is performed within the 1st 2 wk of life.

Ras hkind m ane uve r a nd s te nting o f ASD to the p a tie nt a dm itte d with s e ve re c ya no tic he a rt d is e a s e (be fo re s urg e ry ).

Surgery: Arterial switch

OTHER CYANOTIC CHD

Pulmonary atresia