Page 283 - Concise Pathology for Exam Preparation ( PDFDrive )

268 SECTION II Diseases of Organ Systems

Normal heart Heart with tetralogy of fallot

Aorta

Pulmonary Pulmonary
artery stenosis
Pulmonary
valve
Over-riding
Aortic aorta
valve
Right Left ventricle
ventricle

Thickened right ventricle Ventricular septal defect
FIGURE 11.6. Schematic diagram to demonstrate TOF.

- Two types of TOF exist:
- Cyanotic tetralogy (Flowchart 11.7)

Prominent pulmonary stenosis and mild VSD

More resistance to outflow of blood from right ventricle

Right to left shunt at ventricular level

Cyanosis

FLOWCHART 11.7. Pathogenesis of cyanotic tetralogy.

Effects
- Pressure hypertrophy of right atrium and right ventricle
- Smaller and abnormal tricuspid valve
- Smaller left atrium and left ventricle
- Enlarged aortic orifice
Acyanotic tetralogy (Flowchart 11.8)

VSD larger, pulmonary stenosis mild

Mainly left to right shunt

Increased pulmonary flow

Increased volume in left heart
FLOWCHART 11.8. Pathogenesis of acyanotic tetralogy.

Effects
- Pressure hypertrophy of right ventricle and right atrium
- Volume hypertrophy of left atrium and ventricle
- Enlargement of mitral and aortic orifices

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