Congenital Heart Disease part 1

Definition - abnormalities of the heart/great vessels present from birth

aetiology - idiopathic, genetic ( turner's syndrome, trisomies 13,15,18,21), environmental (rubella, thalidomide, alcohol, oestrogenic steroids, lithium, phenytoin)

4 major subgroups

1. Right to left shunt

2. Left to right shunt

3. obstructive

4. no shunt

what is a shunt? it is an abnormal communication between chambers or blood vessels.

Right to left shunt (cyanotic)

1. Patent truncus arteriosus - due to failure of truncus arteriousus to separate into aorta and pulmonary artery. single artery receiving blood from both ventricles. always overides a VSD. complications = heart failure, recurrent respi tract infections, early death.

2. Tetralogy of Fallot - 4 features!!!

• 1. VSD - malaligned membraneous location

• 2. Right ventricular hypertrophy - RV outflow obstruction leading to increased right pressure leading to compensatory RV hypertrophy.

• 3. subpulmonary stenosis - narrowing of pulmonary valve leading RV outflow obstruction.
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• 4. dextraposed aortic root that overrides VSD - aorta shifted to the right instead of the usual left.

ASD may sometimes be present. TOF presents with dyspnea, squatting position of child, cerebral thrombosis, clubbing. Surgery offers excellent results

3. Transposition of great vessels - aorta rises from the right ventricle, pulmonary artery rises fomr the left ventricle. Atria-ventricular connections are normal. Due to abnormal formation of truncal and aortopulmonary septa, CYANOSIS IS PREDOMINANT. May be associated with VSD, PDA and ASD.

4. Tricuspid atresia - complete occlusion of the tricuspid valve orifice. Due to unequal division of the AV canal. Mitral valve will be larger than normal, hypoplasia of RV noted, right to left shunt via interatrial communication. Ebstein malformation - downward displacement of abnormal valve into right ventricle. ventricle divides into atrialized ventricle and functional ventricle.leads to arrythmias, tachycardia, palpitations, sudden death, right ventricular dilation.

Mnemonic for Right to left shunt - PT3 - one P for Persistant Truncus arteriosus, 3 T's for Tetralogy of Fallot, Tricuspid atresia and Transposition of great vessels.