Congenital Heart Disease: Dong Huifang

Congenital Heart Disease Dong HuiFang

Review: The fetal circulation In the fetus, gas and metabolite exchange are provided by the placenta, the lungs do not provide gas exchange, and vessels in the pulmonary circulation are vasoconstricted. There are three cardiovascular structure unique to the fetus that are important for maintaining this parallel circulation: the ductus venosus, foramen ovale, and the ductus arteriosus.

After birth: ♦ The pulmonary vascular resistance rapidly

decrease. ♦ The systemic vascular resistance increase. the foramen ovale close ♦ The ductus arteriosus close. ♦ The ductus venous close.

Prevalence ♦ 1. Congenital heart disease occurs in 0.5-0.8% of

live births. ♦ 2. The incidence is higher among stillborns (34%), abortuses (10-25%), and premature infants. (about 2%). ♦ 3. There is a wide spectrum of severity in infants with congenital cardiac defects. ♦ 2-3 in 1,000 newborn infants will be symptomatic with heart disease in the first year of life.

Prevalence ♦ 4. The diagnosis is established by 1 week of

age in 40-50% of patients and by 1 month of age in 50-60%. ♦ 5. With the advances in both palliative and corrective surgery, the number of children with congenital heart disease surviving to adulthood has increased dramatically but it remains the leading cause of death in children with congenital malformations.

Etiology ♦ The cause of most congenital

heart disease is unknown but it has the relations with the following factors.

一 .Genetic factors 1: CHD result from gene mutation or chromosome abnormality. ♦ 1. Certain types of VSDs are more common

in children of Asian background. ♦ 2. The recurrence risk of congenital heart disease increase if a 1st-degree relative is affected.

一 .Genetic factors 2 ♦ 3. 3% of patients with congenital heart

disease have an identifiable single gene defect. ♦ 4. 13% of patients with congenital heart disease have an associated chromosomal abnormality.

二 .Environmental factors ♦ 2-4% of cases of congenital heart disease

are associated with known environmental or adverse maternal conditions, including maternal diabetes, maternal rubella during pregnancy or maternal alcoholism and so on.

三 .Gender ♦ 1. Transposition of the great arteries and

life-side obstructive lesions are slightly more common in boys; ♦ 2. ASD,VSD, PDA and pulmonic stenesis are more common in girls.

四 .Race ♦ 1.There are no racial difference in the

occurrence of congenital heart disease as a whole; ♦ 2.For specific lesions such as transposition of the great arteries, a higher occurrence may be seen in white than in black infants.

Hemadynamics ♦

pressure gradients: the higher the pressure gradient, the greater the rate of flow. ♦ flow: ♦ resistance : the higher the resistance, the less the rate of flow. ♦ SO2: SVC/IVC = RA = RV=PA LA = LV =A

Classification of Congenital Heart Disease ♦ 1. Left to right shunts (Acyanotic Heart Defects):

ASD VSD PDA ♦ 2. Right to left shunts (Cyanotic Heart TOF TGA ♦ 3. No shunts ( Obstructive lesions): PS PA

Defects):

The Left-to-Right Shunt Lesions ♦ 1.Ventricular Septal Defect (VSD) ♦ 2.Atrial Septal Defect (ASD) ♦ 3.Patent Ductus Arteriosus(PDA)

Ventricular Septal Defect (VSD)

♦ VSD

is the most common cardiac malformation accounting for 25-50% of congenital heart disease. Defects may occur in any portion of the ventricular septum.

Hemodynamics Figure of VSD

Classification of VSD ♦ Small type VSD: < 0.5cm2 ♦ Middle type VSD : 0.5-1cm2 ♦ Large type VSD: >1cm2

Hemodynamics of VSD Small VSD

no hemodynamics changes

Large VSD

Large left-to-right shunts Pulmonary Hypertension (PH)

Obstructed PH

Dynamic PH

Eisenmenger Syndrome

Pathophysiology ♦ 1. The shunt magnitude ♦ (1).The physical size of the VSD is

a major, but not the only, determinant of the size of the leftto-right shunt. ♦ (2). It is also determined by the level of pulmonary vascular resistance. ♦ (3). Pressure gradient.

♦ 2.Shunt direction: ♦ 3.pulmonary arterial hypertension.

With continued exposure of the pulmonary vascular bed to high systolic pressure and high flow pulmonary vascular obstructive disease develops. (Eisenmenger)

♦ 4. The main pulmonary artery,

left atrium, and left ventricle enlarged.

Clinical manifestation ♦ Symptoms :

cyanosis, feeding difficulties, frequent respiratory infections, grow slowly, very

poor weight, dyspnea, exercise intolerance, fatigue, congestive heart failure .

Clinical manifestation ♦ Signs : 1. A grade 3-4/6, medium-to-high pitched , harsh pansystolic murmur at the left sternal border (LSB) in the 3rd and 4th intercostal spaces, frequently accompanied by a systolic thrill. 2. The pulmonary component of S2 may be increased, indicating pulmonary hypertention. 3. A diastolic murmur indicate VSD combine with aortic regurgitation.

Complication of VSD ♦ Bronchopneumonia ♦ Congestive heart failure ♦ Pulmonary edema ♦ Infective endocarditis

Laboratory diagnosis ♦ 1. The chest radiograph :

(1) small defects: usually normal; (2) large defects: shows gross cardiomegaly with prominence of both ventricles, the LA, and pulmonary artery.

♦ 2. The electrocardiogram :

(1)small defects: usually normal but may suggest left ventricular hypertrophy. (2)large defects : shows biventricular hypertrophy; P waves may be notched or peaked.

♦ 3. Echocardiogram: shows

the position and size of the defects 、 shunt size and direction 、 RV pressure 、 pulmonary vascular pressure.

♦ (1).In small defects, the defect is only

visualized by color Doppler examination. ♦ (2).In membranous septum defects, a thin

membrane can partially cover the defect and limit the volume of the left-to-right shunt.

♦ 4.Cardiac catheterization:

It is usually performed only when a comprehensive clinical evaluation leaves continued uncertainty regarding the size of the shunt, when laboratory data do not fit well with the clinical findings, or when pulmonary vascular disease is suspected.

♦ the oxygen saturation level of the LV is

higher than normal, the pulmonary artery pressure is generally increased above normal.

Prognosis ♦ 1. The natural course of a VSD depends to a

large degree on the size of the defect; ♦ 2. A significant number (30-50%) of small

defects close spontaneously most frequently during the 1st year of life.

♦ 3. Small muscular VSDs are more likely to

close than membranous VSDs. ♦ 4. Some long-term studies of adults with

unoperated small VSD show an increased incidence of arrhythmia, subaortic stenosis, and exercise intolerance.

♦ 5.It is less common for moderate or large VSDs to

close spontaneously, although even defects large enough to result in heart failure may become smaller, and up to 8% may close completely. ♦ 6. More commonly, infants with large defects have

repeated episodes of respiratory infection and heart failure.

♦ 7. Pulmonary hypertension occurs as a result

of high pulmonary blood flow. ♦ 8. Patients with VSD are also at risk for the

development of aortic valve regurgitation. ♦ 9. Eisenmenger syndrome .

Treatment

1.Small VSD ♦

Parents should be reassured of the relatively benign nature of the lesion, and the child should be encouraged to live a normal life, with no restrictions on physical activity.

♦ Surgical repair is currently not recommended. ♦ As a protection against infective endocarditis the

integrity of primary and permanent teeth should be carefully maintained.

2. Large VSD: (1) Medicine two aims : ♦ To control heart failure; ♦ To prevent the development of pulmonary vascular disease.

(2)Surgical Indications ♦ 1. patients at any age with large defects in

whom clinical symptoms cannot be controlled medically. ♦ 2. infants between 6 and 12 months with

large defects associated with pulmonary hypertension.

Atrial Septal Defect (ASD)

ASD ♦ 1. Atrial septal defects (ASDs) can occur in

any portion of the atrial septum (secundum, primum, or sinus venosus), ♦ 2. Isolated secundum ASDs account for 7% of congenital heart defects.

Hemodynamics Figure of ASD

Hemodynamics of ASD pulmanary vein ASD

Inferior/superior vena cave RA （ enlarge ）

LA

RV （ enlarge ） LV （ blood ） Pulmanary blood volume shunt fromright to left

body circulation blood （ less weight 、

fatigue 、 pale 、 sport intolerence ）

Pathophysiology ♦ 1. The degree of left-to-right shunting is

dependent on the following factors: ♦ (1) The size of the defect, ♦ (2) The relative compliances of the right and left ventricles, ♦ (3) The relative vascular resistances in the pulmonary and systemic circulations.

♦ 2. large defects, ♦ (1) A considerable shunt of oxygenated

blood flows from the left to the right atrium. This blood is added to the usual venous return to the right atrium and is pumped by the right ventricle to the lungs. ♦ (2) The ratio of pulmonary to systemic blood flow (Qp:Qs) is usually between 2 and 4:1.

♦ 3. The paucity of symptoms in infants with

ASDs is related to the structure of the right ventricle in early life when its muscular wall is thick and less compliant, thus limiting the left-to-right shunt.

♦ 4. As the infant becomes older, and

pulmonary vascular resistance drops, the right ventricular wall becomes thinner, and the left-to-right shunt across the ASD increases.

♦ 5. The large blood flow through the right

side of the heart results in enlargement of the right atrium and ventricle and dilatation of the pulmonary artery. ♦ 6. The left atrium may be enlarged; however, the left ventricle and aorta are normal in size. ♦ 7. The pulmonary arterial pressure is usually normal

Clinical manifestation ♦ Symptoms : similar with that of VSD

cyanosis, feeding difficulties, frequent respiratory infections, grow slowly, very poor weight, dyspnea, exercise intolerance, fatigue, congestive heart failure .

♦ Signs : 1. A grade 1-3/6 ejection SM is heard best at the LSB in the 2nd intercostal space ， no thrill . 2. S2 at the pulmonary area is widely split and often fixed . 3. The pulmonary component of S2 is accentuation in intensity . 4. A mid-diastolic murmur can often be heard in tricuspid area .

LABORATORY DIAGNOSIS. ♦ 1.The chest roentgenogram shows varying

degrees of enlargement of the right ventricle and atrium depending on the size of the shunt. ♦ 2.The pulmonary artery is large, and the pulmonary vascularity is increased.

X Ray of secundum ASD

肺野充血 ，肺动脉 段突出， 右房、右 室增大

♦ 3. Cardiac enlargement is often best

appreciated on the lateral view because the right ventricle protrudes anteriorly as its volume increases. ♦ 4.The electrocardiogram shows volume overload of the right ventricle.

♦ 5.The echocardiogram shows findings

characteristic of right ventricular volume overload. The shunt is confirmed by pulsed and color flow Doppler.

♦ 6.The cardiac catheterization will reveal the

separation in the atrial septum and the increased oxygen saturation in the right atrium. The catheter can usually be manipulated into the left atrium via the defect.

PROGNOSIS ♦ 1. Secundum ASDs are well tolerated

during childhood; symptoms usually do not appear until the 3rd decade or later. ♦ 2.Pulmonary hypertension, atrial dysrhythmias, tricuspid or mitral insufficiency, and heart failure are late manifestations.

COMPLICATIONS ♦ Bronchopneumonia ♦ Congestive heart failure ♦ Infective endocarditis

Treatment ♦ 1.Surgery : before school age ♦ 2. Cardiac catheterization ♦ 3. The prognosis is excellent.

Patent Ductus Arteriosus (PDA)

♦ 1. During fetal life, most of the pulmonary

arterial blood is shunted through the ductus arteriosus into the aorta; ♦ 2. Functional closure of the ductus normally occurs soon after birth, but if the ductus remains patent when pulmonary vascular resistance falls, aortic blood is shunted into the pulmonary artery.

PDA ♦ 3 PDA accounts for about 15-20% of all

congenital heart disease. It occurs more frequently in girls than boys.

PDA ♦ 5. PDA is also associated with

maternal rubella infection during early pregnancy. ♦ 6. A PDA is seen in 10% of patients with other congenital heart lesions and often plays a critical role in providing pulmonary blood flow.

Hemodynamics Figure of PDA

Anatomopathological Diagram of PDA

Hemodynamics Figure of PDA RV blood systemic circulation

PDA

Pulmanary artery plumnary blood

aorta PH

blood Eisenmenger Syndrome

LA 、 LV enlarge

PATHOPHYSIOLOGY. ♦ 1 As a result of the higher aortic

pressure,blood shunts left to right through the ductus, from the aorta to the pulmonary artery. ♦ 2 The extent of the shunt depends on the size of the ductus and on the ratio of pulmonary to systemic vascular resistances.

♦ 3 In extreme cases, 70% of the left

ventricular output may be shunted through the ductus to the pulmonary circulation. ♦ 4. small PDA: the pressures within the pulmonary artery, the right ventricle, and the right atrium are normal.

♦ 5 large PDA: ♦ (1) pulmonary artery pressures

may be elevated to systemic levels during both systole and diastole. ♦ (2) high risk for the development of pulmonary vascular disease if left unoperated. ♦ (3)a wide pulse pressure due to run-off of blood into the pulmonary artery during diastole.

CLINICAL MANIFESTATIONS

♦ Symptoms : similar with that of VSD and

ASD cyanosis, feeding difficulties, frequent respiratory infections, grow slowly, very poor weight, dyspnea, exercise intolerance, fatigue, congestive heart failure .

CLINICAL of PDA ♦ Signs:

1. A characteristic thrill and continuous and rough “machinery” murmur with a late systolic accentuation will be heard at the upper left sternal border or under the left clavical in old children. 2. A diastolic flow murmur is often heard at the apex . 3. Peripheral vascular sign: water hammer pulse, pistol shot sound, capillary pulsation. 4. Differential cyanosis and clubbing .

LABORATORY DIAGNOSIS ♦ 1 Electrocardiogram :

(1) small ductus : normal; (2) large ductus : left ventricular or biventricular hypertrophy is present.

♦ 2 Radiographic :

(1) The cardiac size may be normal or moderately to markedly enlarged. The chambers involved are the left atrium and ventricle. (2) The aortic knob is normal or prominent. (3) The pulmonary artery prominent with increased intrapulmonary vascular markings.

♦ 3 The echocardiography :

(1) the cardiac chambers is normaly if the ductus is small. (2) With large shunts, left atrial and left ventricular dimensions are increased.

♦ 4 Cardiac catheterization :

(1) The pressures of right ventricle and pulmonary artery may be normal or increased. (2) The presence of oxygenated blood shunting into the pulmonary artery confirms a left-toright shunt. (3) The catheter may pass from the pulmonary artery through the ductus into the descending aorta.

PROGNOSIS AND COMPLICATIONS ♦ 1. A small PDA may no cardiac symptoms;

however, late manifestations may occur. ♦ 2. Spontaneous closure of the ductus after

infancy is extremely rare.

♦ 3 Cardiac failure most often occurs in early

infancy in the presence of a large ductus but may occur late in life even with a moderatesized communication. ♦ 4 Infective endarteritis may be seen at any

age.

♦ 5 Pulmonary or systemic emboli may occur. ♦ 6 Pulmonary hypertension (Eisenmenger's

syndrome) usually occurs in patients with a large PDA who do not undergo surgical treatment .

TREATMENT.

♦ 1. medicine: indomethacin --- a

prostaglandin inhibitor ♦ 2. surgery ♦ 3. catheter closure.

1. Medical management ♦ Medical management for the child may

consist of the administration of oral or IV indomethacin, a prostaglandin inhibitor.

2.surgery ♦ (1) treatment should not be unduly

postponed after adequate medical therapy of cardiac failure has been instituted. ♦ (2) ligation and division of the ductus are

indicated preferably before 1 yr of age.

3. catheter closure. ♦ (1) Small PDAs are closed using

intravascular coils. ♦ (2) Moderate to large PDAs may be closed

with several coils or an umbrella-like device.

Interventional treatment of PDA

Common features of left-to-right shunting CHD ♦ In general there are no cyanosis ♦ A rough murmur is heard in precordium ♦ Pulmonary flow increase and easy to

suffer from bronchopneumonia ♦ Systemic flow decrease and the patient

grow slowly

Tetralogy of Fallot (TOF)

The four malformations of TOF ♦ Pulmonary artery stenosis ♦ Ventricular septal defect ♦ Overriding of the aorta ♦ Right ventricular hypertrophy

PATHOPHYSIOLOGY

Hemodynamics Figure of TOF

CLINICAL MANIFESTATIONS Symptoms : ♦ Cyanosis is the main symptoms ♦ Dyspnea and hypoxemic spells ♦ Squatting posture or knee chest position ♦ Clubbing of the terminal digits ♦ Syncope ♦ polycythemia

Clubbing of fingers

Clubbing of fingers and toes

Signs: ♦ There is a grade 2-4/6, rough, ejection-type

SM that is maximal at the LSB in the 2nd to 3rd intercostal space and that radiates well to the back. The pulmonary component of S2 weaken in intensity

LABORATORY DIAGNOSIS ♦ 1 X-ray :

右室大、 心尖上翘 呈靴形， 肺动脉段 凹陷，肺 野清晰

LABORATORY DIAGNOSIS ♦ 2 The electrocardiogram:

right ventricular hypertrophy.

LABORATORY DIAGNOSIS ♦ 3. Two-dimensional echocardiography:

Establishes the diagnosis and provides information as to the extent of aortic override of the septum,the location and degree of the right ventricular outflow tract obstruction, the side of the aortic arch.

LABORATORY DIAGNOSIS ♦ 4. Cardiac catheterization : ♦ (1) a systolic pressure in the right

ventricle equal to systemic pressure. ♦ (2) the pulmonary arterial pressures are usually lower than normal. ♦ (3) The level of arterial oxygen saturation decrease.

LABORATORY DIAGNOSIS ♦ 5. Selective right ventriculography best

demonstrates the anatomy of tetralogy of Fallot.

右室造影 AO 和 PA 同时显影 ，大动脉 关系正常 ， RVOT 变 窄， AO 内径增宽 并骑跨于 室间隔上 。

LABORATORY DIAGNOSIS ♦ 6 Left ventriculography ♦ (1) demonstrates the size of the left

ventricle, the position of the VSD, and the overriding aorta; ♦ (2) confirms mitral-aortic continuity, ruling

out double-utlet right ventricle.

COMPLICATIONS ♦ 1 Cerebral embolism

Thromboses occur most often in patients less than 2 yr of age.

♦ 2 Cerebral abscess

Brain abscess is less common than cerebral vascular events. Patients are usually older than 2 yr of age.

♦ 3 Infective endocarditis

Bacterial endocarditis may occur in the right ventricular infun-dibulum or on the pulmonic, aortic or, rarely, tricuspid valves.

♦ 4 Heart failure

Heart failure is not a usual feature . As the degree of pulmonary obstruction worsens with age, the symptoms of heart failure resolve and eventually the patient experiences cyanosis.

TREATMENT. ♦ Surgery

Diagnosis of CHD ♦ History ♦ Physical examination ♦ Examnations:

♦ History:

1. Feeding difficulties, tachycardia, tachypnea, the infant who is breathing rapidly has to stop sucking frequently to breath. Easily fatigued because of ineffective heart action and has to stop sucking to rest before finishing a feeding.

2. Pregnancy history: intrauterine infection such as toxoplasmosis, cytomegalovirus, or rubella . Ask if any medication was taken during pregnancy, if nutrition was adequate, or whether any radiation was used, since these may also contribute to CHD.

3. Ask how much activity does it take before the child becomes tired; Ask about the child’s usual position when resting; Ask about frequency of infections; Ask whether perspire excessively or edema;

4. Cyanosis will be reported as a sign in children with cyanotic heart disease. 5. Growth and development slowly.

♦ Physical examination

1. Inspect the toes and fingers for clubbing and for colour. 2. Observe children for lethargy, rapid respirations, or abnormal body posture, symptoms that the heart is an ineffective pump.

3.Heart Rate Tachycardia is a pulse rate more than 160 bpm in an infant and more than 100 bpm at 3 years of age. An increase in pulse rate over this ratio needs further investigation. Tachycardia is particularly significant if it persists during sleep, when the possibility of excitement is removed.

4. Murmur Murmurs of no significance are termed functional insignificant or innocent murmurs. Innocent murmurs may become more pronounced during febrile illness and anxiety. If a murmur is the result of heart disease or a congenital defect, it is termed an organic murmur.

For assessment, any murmur heard should be described according to its position in the cardiac cycle, duration, quality, pitch, intensity, location where it is heard best, whether a thrill is present, and the response of the murmur to exercise or change of position.

♦ Diagnostic Tests

1.Electrocardiogram 2. X-ray 3. Echocardiography 4. Cardiac catheterization

Interventions ♦ Schedule proper daily life routine:

Maintaining enough rest and sleep, appropriate activities, avoid long time crying.

♦ Provide adequate nutrition

Prevent iron deficiency anemia during the first year. Given supplemental vitamins , high calorie or fed by enteral of gastrostomy technique.

♦ Monitor the progress of disease and prevent

infection infectious endocarditis antibiotic therapy before oral surgery routin immunization avoid dehydration observe early signs of left heart failure

♦ Review steps for follow-up care and

emergencies.

Thanks for Your attention ！