Page 284 - Concise Pathology for Exam Preparation ( PDFDrive )

11 Disorders of the Heart 269

- ‘Boot shaped heart’ may result owing to marked right ventricular hypertro-
phy (particularly of apical region)
- Complete surgical repair is possible for TOF but is more complicated for
patients with pulmonary atresia and dilated bronchial arteries.
(ii) Transposition of great arteries
- Complex malformations as regards position of the aorta, pulmonary trunk,
atrioventricular orifices and position of atria in relation to ventricles
- Several forms of transpositions are encountered:
- Regular transposition:
- Most common type
- Aorta (normally situated to the right and posterior with respect to
pulmonary trunk), displaced anteriorly and to the right
- Aorta emerges from the right ventricle and pulmonary trunk from
the left ventricle so there is cyanosis from birth
- Corrected transposition: Transposition of great arteries and veins
(pulmonary veins enter the right atrium and systemic veins drain into
the left atrium) resulting in ‘physiological correction’
(iii) Persistent truncus arteriosus:
- Arch separating aorta from pulmonary artery fails to develop.
- Single large common vessel receives blood from right and left ventricles.
- Associated VSD is common.
- Left to right shunt and early systemic cyanosis is typical.
(iv) Tricuspid atresia and stenosis:
- Rare; often associated with pulmonary stenosis or atresia
- May be accompanied by an interatrial defect through which right to left
shunting of blood takes place leading to early cyanosis
3. Obstructive CHD
(a) Coarctation of aorta
• Localized narrowing in any part of aorta commonly located below the origin of
the subclavian artery
• May be associated with a bicuspid aortic valve in 70% cases, Berry aneurysm in
the circle of Willis and Turner syndrome
• Two main types:
- Postductal or adult type:
- Obstruction distal to the point of entry of ductus arteriosus
- Aorta is dilated on either side of the constriction
- Condition usually recognized in adulthood when it manifests with hyper-
tension in upper extremities, weak pulses and low blood pressure in the
lower extremities
- Effects of arterial insufficiency, eg, claudication and coldness are
common
- Collateral circulation between prestenotic and poststenotic arterial
branches leads to enlarged and palpable intercostal arteries
- Erosions on the inner surface of ribs may be seen
- Preductal or infantile type:
- Narrowing is proximal to ductus arteriosus (aortic arch, ascending aorta)
- Manifests with cyanosis in lower half of the body; upper half remains un-
affected as it is supported by vessels originating proximal to the
coarctation
- Has a poor prognosis
(b) Aortic stenosis and atresia
• Most common anomaly of aorta is a bicuspid aortic valve which has no func-
tional significance except calcification.
• Congenital aortic atresia is rare and incompatible with survival.
• Aortic stenosis may be congenital or acquired. Causes of the latter include RHD
and calcified aortic stenosis.
• Congenital narrowing of the aortic valve can occur in the valvular, subvalvular
and supravalvular locations.

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