CONGENITAL HEART DISEASE IN CHILDHOOD

2. CONGENITAL HEART DISEASE IN CHILDHOOD

3. 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

4. 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

5. 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 Relative prevalence of specific CHDs (%)

6. 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 ).

7. 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 )

8. 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

9. 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

10. Diagnostic approaches and tools

15. 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 TAPVRTruncus UVH

16. VENTRICU LARSEPTAL DEFECT

17. Pathology ◆Perimembranous (membranous) 80% ◆ Subpulmonic (supracristal) 5~7% ◆ Muscular the rest

21. 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’

22. Pathophysiology( hemodynamics ) Vena RA RV PA cava pulmonary blood flow LA LV Ao

23. Clinical manifestation • Small VSD symptom-free • Moderate to large VSD：dependent on the shunt size ◆ Exercise intolerance CHF ◆ Repeated pulmonary infections ◆ (Cyanosis) ◆ (Delayed growth)

26. Physical Examination◆loud P2 sound ◆pansystolic harsh murmur at left sternal border, 3~5/6 grade / thrill◆mid-diagnostic murmur at apex

28. X-ray

32. 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

34. Management 1)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

37. 3) Transcatheter intervention Developed for just a couple of years but quickly become popular and tends to substitute a part of surgery

38. Interventional procedure for VSD

39. Atrial Septal Defect

40. Classification and pathogenesis ◆ Secondum type ASD II ◆ Primum type ASD I also: as a component of endocardial cushing defect/ atrioventricular septal defect

43. Pathophysiology( hemodynamics ) Vena RA RV PA cava pulmonary blood flow LA LV Ao

44. 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 ).

45. 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

46. 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.

47. ASD X-Ray