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CONGENITAL HEART DISEASE
IN CHILDHOOD
Definition
Cardiovascular malformation(s) resulted from deficient or interrupted development of heart embryo, or delayed degeneration of a cardiac structure after birth.
Basic deformities consisting CHDs are:• abnormal communication• obstruction to flow• abnormal connection between cardiac segments• combination of the above
Incidence
• 7~8/1000 live births
• 150,000 new born cases of CHD
each year in China
• 20-30% CHD cases die before
their first birthday
Relative prevalence of specific CHDs (%)
Canada(15104 live births) China( 2659 autopsies )
VSD 28 24.6 PDA 10 6.7 ASD 10 13.5 Coarc. 5 6.9 TGA 5 6.7 ToF 10 5.2 PS 10 - AS 7 - Truncus 0.7 3.3 TA 1.2 - Others 13.1 33.1
Etiology Clear-cut genetic 8% • 5% chromosomal e.g 21-trisomy
Turner’s(XO) • 3% single gene e.g Marfan’s (AD)
Hunter’s (XR)
Definitely environmental 2% e.g Rubella / PDA
In most instance, however, CHDs are results of interaction of genetic predisposition and environmental insults during early gestation( 4-8weeks ).
Shift of threshold The threshold of CHD due to environmental without environmental factors factors
A B C A: Families without CHD susceptibility B: Families with moderate CHD susceptibility C: Families with severe CHD susceptibility
The hypothesis on the etiology of CHD ( by Nora JJ,1968 )
New horizon
• Recent genetic research has led to a viewpoint: “inherited CHDs” seem much more frequent than previously thought
• Single gene defect or gene allele microdeletion (such as 22q11 ) often cause CHD
Clinical classification Non-cyanotic group
◆ L→R shunts ‘potentially cyanotic’ e.g. ASD,VSD,PDA. ◆ No shunt obstruction/stenosis, e.g. AS, PS, Coarc. Cyanotic group ◆ R→L shunts, may be a wrong connection of segments e.g. TGA, ToF
Diagnostic approaches and tools
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无 创检查
心 导管术 造 影术
有 创检查
心 脏特殊检查
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Doppler
CHDs
Observ /Hct Acyanotic Cyanotic
X-ray PBF→ PBF↑ PBF↓ PBF↑
ECG RVH LVH RVH LVH RVH LVH RVH LVH
or CVH or CVH
PS AS ASD VSD ToF TA TGA TGA/PS
PDA TAPVR Truncus
UVH
VENTRICU LARSEPTAL DEFECT
Pathology
◆ Perimembranous (membranous)
80%
◆ Subpulmonic (supracristal)
5~7%
◆ Muscular
the rest
Size of VSDs
Large Moderate Small
VSD diameter(mm) > 5 3~5 < 3
VSD area/ aorta area 1/2~1 1/2 ¼
◆ When VSD area approaches that of aorta, it is refered to as ‘unrestrictive VSD’
Pathophysiology( hemodynamics )
Vena RA RV PA
cava
pulmonary
blood flow
LA LV Ao
Clinical manifestation
1) Small VSD symptom-free
2) Moderate to large VSD : dependent on the shunt size
◆ Exercise intolerance CHF
◆ Repeated pulmonary infections
◆ (Cyanosis)
◆ (Delayed growth)
Physical Examination
◆ loud P2 sound
◆ pansystolic harsh murmur at left sternal border, 3~5/6 grade / thrill
◆ mid-diagnostic murmur at apex
X-ray
Natural history and complications
◆ Spontaneous closure in at least 1/4~1/3 cases
◆ Infundibular stenosis may develop in 5~15%
◆ A small portion will develop aortic insufficiency
◆ In large VSD, pulmonary vascular obstructive pathology
may develop leading to reversed shunt----Eisengmenger’s syndrome
◆ Infectious endocarditis
Management1) Medical
◆ Control of CHF with digitalis, diuretics and vasodilators in early infancy◆ Treatment of pulmonary infections◆ Prophylaxis against infectious endocarditis
2) Surgical
◆ Indication---- Qp/Qs≥1.3:1. If there is significant pulmonary hypertension, the repair should be performed by 12~18months◆ Contraindication------ Eisenmenger’s syndrome
3) Transcatheter intervention
Developed for just a couple of years but quickly become popular and tends to substitute a part of surgery
Interventional procedure for VSD
Atrial Septal Defect
Classification and pathogenesis
◆ Secondum type ASD II
◆ Primum type ASD I
also: as a component of
endocardial cushing defect/
atrioventricular septal defect
Pathophysiology( hemodynamics )
Vena RA RV PA
cava
pulmonary
blood flow
LA LV Ao
Clinical manifestations
◆ Usually asymptomatic in childhood
◆ Increased susceptibility to respiratory infections and some degree of exercise intolerance may occur in large shunts
◆ Pulmonary vascular obstruction, congestive heart failure and arrhythmias( flatter/fibrillation ) likely to develop in adult life ( 3rd ~4th decade ).
Late complications of ASD• Decreased left ventricle distensibility
augments L-R shunt pulmonary hypertension
• RA dilatation atrial arrhythmias
• Symptomatic CHF which can be precipitated by the arrhythmia
Physical examination
◆ Widely split and fixed P2
◆ Grade 2~3/6 ejective systolic murmur
at upper left sternal border.
◆ Mid-diastolic rumble at lower left sternal
border, when the shunt is large.
ASD X-RayASD X-Ray
Management
◆ Elective surgical repair at age 4~5years
◆ Transcatheter occlusion of the defect with
artificial device has been widely accepted
to substitute surgery in the majority of cases
◆ Chemoprophylaxis against IE is not
indicated
Interventional procedure for ASD
Patent Ductus Ateriousus
Pathophysiology( hemodynamics )
Vena RA RV PA
cava
pulmonary
blood flow
LA LV Ao
Clinical manifestations
◆ Small ductus ----- asymptomatic.
◆ Large ductus ----- Similar to Large VSD
including the development of
pulmonary vascular obstruction pathology
when the ‘differential cyanosis’ may be
seen.
Physical examination ◆ A machinery-like continuous murmur at upper
left sternal border. P2 is usually loud but may
be obscured by the murmur.
◆ Mid-diastolic rumble at apex, when the shunt is
large.
◆ Peripheral vascular signs ---- bounding pulse /
pistol sound/capillary pulsation --- associated
with wide pulse pressure.
PDA X-RayPDA X-Ray
Management
1) Medical
◆ Care for medical complications similar to VSD
(CHF/pneumonia/IE prophylaxis,etc)
◆ Closure of PDA in premature neonates can be
precipitated by fluid restriction / Indomethacin
2) Surgical ligation
◆ Elective, anytime after 6 month except
intractable CHF
3) Transcatheter occlusion
◆ Has recently become the management of choice
Tetralogy of Fallot
Pathophysiology( hemodynamics )
Vena RA RV PA
cava
pulmonary
blood flow
LA LV Ao
Pathophysiological implication
◆ Pressures of both ventricles are balanced by a large VSD, RV pressure never exceeds systemic level, so that cardiomegaly / CHF rarely develop
◆ The more stenotic the RV outflow, the more severe the cyanosis. Therefore the two ends of the spectrum: mild PS---- ‘pink’ tetrology vs. most severe PS---- pulmonary atresia with VSD
◆ The PS is relatively fixed, hence the size of R→L is inversely correlated to SVR.
Clinical manifestations
◆ Cyanosis typically develops in 3~6 months of age
◆ Mostly symptomatic with dyspnea on exertion and delayed growth may exist
◆ Hypoxemic spells in infancy characterized by
◆ Squatting, usually appears when the patient begins to walk
◆ Brain abscess / thrombosis and tendency of
bleeding which may relate to rheological disorder
paroxysms of hyperpnea, increasing cyanosis, attenuation
of the murmur and may lead to convulsion or even death.
Physical examination ◆ Weak pulmonic component makes S2 sounds
single and weak, but may be loud reflecting A2
◆ Systolic ejective murmur at middle left/upper
sternal border
◆ Central cyanosis with finger/toe clubing
TTOOF X-RayF X-Ray
Management
1) Medical ◆ Antibiotic prophylaxis against endocarditis ◆ Maintain rheological condition at favorable state ◆ Detect and treat hypoxemic spell
2) Surgical ◆ Palliative procedures such as Blalock- Taussig’s for severe cases < 6 month or cases with PA hypoplasia. ◆ Corrective procedure ----- selective, any time after 1.5~2 year of age. However, more centers now prefer early corrective surgery even before 6 month of age.
Treatment of hypoximic spell
RV outlet spasm?
SVR R to L
venus return shunt
◆ Knee-chest position respiratory blood pH
◆ O2 stimulation PCO2
◆ Morphine 0.1~0.2mg/kg, im;
◆ NaHCO3 1mEq/kg, iv;
◆ Vasoconstrictors such as phenylephrine 0.02mg/kg, iv;
◆ Propranolol, especially oral administration for long term
control
Pulmonary Stenosis
Definition
• supravalvular
• valvular
• Subvalvular
Further ClassificationAnatomy• Valvular stenosis without dysplasia (dome-
shape)• Dysplasia of pulmonary valve, frequently
associated with small annulus
Severety pressure gradient• Mild < 40 mmHg• Moderate 41-79 mmHg• Severe > 80 mmHg
Hemodynamics
Pressure overload of RV
RV hypertrophy RA enlargement/pressure
Right heart failure RA LA shunt
Clinical manifestation
• Symptom free in mild to moderate cases, even in severe cases
• Symptoms may include dyspnea and fatigue on effort, in severe cases there may be chest pain, syncope and occasionally sudden death during exercise
• In critical stenosis in infancy, CHF and cyanosis may occur
Physical Examination
• P2 split but usually weak
• Ejective systolic murmur grade 3-5 at 2nd LICS
• Ejective sound( early systolic click )
Bernoulli principle &
pressure gradient
estimation
⊿ P = 4(V22—V1
2) ≈ 4 V2
Treatment Indications for surgery• Symptomatic patients or asymptomatic severe cases • No treatment for mild cases, follow up for asymptomatic moderate patients • Balloon dilatation failed cases, especially with valve and annulus dysplasia
Indication for balloon valvuloplasty
• Pressure gradient >30mmHg• Dome- shaped valve is better indicated than dysplastic valve