CONGENITAL HEART DISEASE.

Anatomy of the Heart

Figure 12.2

Epidemiology

• Prevalence:0.5-0.8% of live births (8/1000).Leading cause ofdeath in children with CHD.

• Etiology:Unknown,multifactorial inheritance,genetic factors implicated,high incidence in first degree relatives.• 3% have a single gene defect,13% have associated

chromosomal abnormalities.• 2-4% are associated with environmental or maternal

conditions & teratogenic influences.• Gender differences:ASD,VSD,PDA & Pulmonic stenosis

more common in girls,left sided lesions in boys.

Recurrence of CHD

Congenital Heart Disease: EtiologiesMost cases (70-80%) are “multifactorial”

The Recurrence Risk with: -1 sib with CHD: 2-4% -2 sibs with CHD: 6-12% -Mother with CHD:6-12% -Father with CHD: 2-4%

In 1/2 of these families the same defect recurs.

Common acyanotic lesions

*Ventricular septal defects

*Atrial septal defects

*Atrio-ventricular septal defects

*Patent ductus arteriosus

*Truncus arteriosus

*Pulmonary stenosis

*Aortic stenosis

*Mitral stenosis/incompetence

*Coarctation of aorta

*Tricuspid regurgitation

Common Cyanotic Lesions

Decreased flow

1. Tetralogy of Fallot

2. Tricuspid Atresia

3. Severe Pulmonic Stenosis

4. Ebstein’s anamoly

Increased Flow

5. Transposition of great vessles

6. VSD with pulmonary atresia

Common Lesions producing cyanosis

7. Truncus Arteriosus

8. Hypoplastic left heart

9. Single ventricle

10. TAPVR with infradiaphragmatic obstruction

Etiology

• Congenital Heart Disease: Etiologies

• 6-12% have gross chromosomal anomalies

• - Trisomy 21 (40% have CHD): AV canal

• - Trisomy 18 (100% have CHD): VSD, PS

• - Trisomy 13- 15: VSD, ASD, TGV

• - XO (Turner): Coarc, AS, VSD• - XXY (Klinefelter): Ebstein,

Tetralogy

PrevalencePrevalence

• CongenitalCongenital• Cyanotic: 22%• Acyanotic: 68%

– VSD 25%– ASD 6%– PDA 6%– TOF 5%– PS 5%– AS 5%

• AcquiredAcquired– Kawasaki disease– Rheumatic– Tubercular– Collagen

Ceylon Med J 2001 Sep; 46 (3): 96-8; Indian J Pediatr. 2001 Aug;68 (8):757-7

Nelson’s Textbook of pediatrics; 17 ed.

Fetal Physiology

• Right-to-left shunting at atrial level (PFO) and at arterial level (ductus

arteriosus)

• High pulmonary vascular resistance• Little pulmonary blood flow

• Ventricles work in parallel

Transition From the Fetal Circulation

• Pulmonary vascular resistance falls• Ductus venosus and ductus arteriosus

close• Right-to-left shunting through foramen

ovale ceases

Timing of these events determines the timing of presentation of congenital heart defects

Cyanosis: is it a cardiac cause or lung cause

• Hyperoxia test

– Neonates with cyanotic congenital heart disease usually do not have significantly raised arterial Pao2 during administration of 100% oxygen.

Ventricular Defect

• Small VSD– Asymptomatic– A loud, harsh, or

blowing holosystolic murmur.

• Large VSD– dyspnea, feeding

difficulties, poor growth, profuse perspiration, recurrent pulmonary infections, and cardiac failure in early infancy.

80%

Syndromes associated with this condition

VSD: ECG is normal but may show right ventricular hypertrophy, if present indicates defect is large and presence of pulmonary hypertension or pulmonry stenosis

Ventricular Septal Defect (VSD)

Large VSD: The presence of right ventricular hypertrophy, olegeimic lung fields (pulmonary hypertension or an associated pulmonic stenosis), gross cardiomegaly with prominence of both ventricles, the left atrium.

Small VSDs, the chest radiograph is usually normal

Ventricular Septal defects• 30–50% of small defects close spontaneously,

most frequently during the 1st 2 yr of life.• Small muscular VSDs are more likely to close

(up to 80%) than membranous VSDs are (up to 35%).

• infants with large defects have repeated episodes of respiratory infection and heart failure despite optimal medical management.

• Surgical repair prior to development of an irreversible increase in pulmonary vasculalr resistance (usually prior to the patient's second birthday).

Investigations

• CXR:cardiomegaly,enlarged LA&LV.• ECG:extreme lt axis is

charecteristic,biventricular hypertrophy.• ECHO:chamber size & pressures.• Cardiac catheter:O2 content,PA pressure,size

& no of defects.• Treatment:Endocarditis

prophylaxis,digoxin,diuretics.• Surgical closure before pulmonary vascular

changes become irreversible.

ATRIAL SEPTAL DEFECT.

• Sinus venosus defect:high in the septum.• Ostium secundum defect:midseptum.• Ostium primum defect:low in the septum.• Pathophysiology:L-R shunt-increased flow

across Rt heart-RV & PA enlargement.• Clinical features:asymptomatic,slow wt

gain,frequent LRTI.• Diagnosis:Rt ventricular heave,systolic

murmur,fixed wide split S2.

Atrial Septal Defects: secundum

• Most common form of ASD (fossa ovalis)

• In large defects, a considerable shunt of oxygenated blood flows from the left to the right atrium.

• Mostly asymptomatic• The 2nd heart sound is

characteristically widely split and fixed. Secundum

Atrial Septal Defects:primum

• Situated in the lower portion of the atrial septum and overlies the mitral and tricuspid valves. In most instances, a cleft in the anterior leaflet of the mitral valve is also noted.

• Combination of a left-to-right shunt across the atrial defect and mitral insufficiency

• C/F similar to that of an ostium secundum ASD

Atrial Septal Defect

• Enlargement of the right ventricle

• Enlargement of atrium• Large pulmonary

artery• increased pulmonary

vascularity is.

ASD primum&secondum

Investigations:

• CXR:enlarged heart & PA,increased vascularity.

• ECG:Rt axis in secundum defect,hallmark of primum defect is extreme Lt axis,RVH.

• ECHO:RVH,valve anatomy,flow direction.

• Treatment:closure during cardiac cathetrization,surgical closure.

PATENT DUCTUS ARTERIOSUS.

• Connection between PA & descending aorta• 10% of CHD.• Pathophysiology:Lt-Rt shunt,reverses if

pulmonary resistance increases-RV enlargement.If PDA is large Eissenmenger syndrome can develop.

• Clinical features:depend on size & direction of flow,slow growth,LRTI,SOB,cyanosis.

• Diagnosis:bounding pulse,continous murmur,loud S2.

Patent Ductus Arteriosus

• Small defect no symptoms.

• Large defect:– Wide pulse pressure– Enlarged heart– Thrill in L second IS– Continuous murmur– X-ray: prominent

pulmonary artery with increased vascular markings.

Investigations

• CXR:cardiomegaly,increased pul vascularity.• ECG:Lt or biventricular hypertrophy.• ECHO:2D visualises PDA,doppler shows

turbulance.• Cardiac catheter:PA pressures & O2 sats.• Treatment:Endocardial prophylaxis as long as

patent,Indomethacin.• Surgical:ligation is curative.