Examine this patient's heart.



· Syncope (in 20% of cases).

· Squatting.

· Shortness of breath.

· Growth retardation.


· Clubbing.

· Central cyanosis.

· Left parasternal heave with normal left ventricular impulse.

· Ejection systolic murmur heard in the pulmonary area.

Signs indicating Blalock-Taussig shunt:

· The left radial pulse is not as prominent as the right.

· The arm on the side of the anastomosis (usually the left) may be smaller than the other arm.

· Blood pressure is difficult to obtain because of the narrow pulse pressure in the arm supplied by the

collateral vessels.

· Thoracotomy scar.


This patient has Fallot's tetralogy with a Blalock-Taussig shunt and is mildly cyanosed, indicating a right

to left shunt (functional status).

Read: N Engl J Med 1993; 329: 655-6.


What are the constituents of Fallot's tetralogy?

· VSD with a right-to-left shunt.

· Pulmonary stenosis (infundibular or valvular).

· Right ventricular hypertrophy.

· Dextroposition of the aorta with it overriding the ventricular septal defect.

What are the complications of Fallot's tetralogy?

· Cyanotic and syncopal spells.

· Cerebral abscess (in 10% of cases).

· Endocarditis (in 10% of cases).

Strokes - thrombotic secondary to polycythaemia.

· Paradoxical emboli.


What do you understand by a Blalock-Taussig shunt?

It is the anastomosis of the left subclavian artery to the left pulmonary artery with the intention to increase

pulmonary blood flow.

Why is it less frequently seen in adults in the recent past?

With ready availability of cardiopulmonary bypass, such patients have total correction of their anomalies

at an early age.

What do you know about the embryological development of Fallot's tetralogy?

It arises from the anterior displacement of the canal septum, which leads to unequal partitioning of the

conus at the expense of the right ventricular infundibulum and results in the obstruction of the right

ventricular outflow tract and failure to close the intraventricular foramen.

What is the treatment for Fallot's tetralogy?

· Total correction under the age of 1 year when there is no need for an outflow transannular patch. A

second-stage total correction can be performed when the child is over the age of 2 years.

· Blalock-Taussig shunting is performed nowadays only if the anatomy is unfavourable for a total


· Modified Blalock-Taussig shunting is the interposition of a tubular graft between the subclavian and

pulmonary arteries.

· The Waterston shunt involves anastomosis of the back of the ascending aorta to the pulmonary

artery. A Waterston shunt is performed when surgery is required under the age of 3 months because

the subclavian artery is too small for a good Blalock-Taussig shunt.

· The Potts shunt involves anastomosis of the descending aorta to the back of the pulmonary artery

(JAMA1946; 132: 627).

· The Glenn operation involves anastomosis of the superior vena cava to the right pulmonary artery.

The bidirectional Glenn procedure involves anastomosis of the superior vena cava to both pulmonary


· Pulmonary balloon valvuloplasty is sometimes used as an alternative to surgery.

Which cardiac lesions favour an initial shunt?

· Anomalous coronary artery.

· Single pulmonary artery.

· Hypoplastic pulmonary arteries.

· Single pulmonary artery.

What is Fallot's trilogy?

ASD, pulmonary stenosis and right ventricular hypertrophy.

What is Fallot's pentalogy?

Fallot's tetralogy with associated ASD is known as Fallot's pentalogy.

What conditions are associated with Fallot's tetralogy?

· Right-sided aortic arch (in 30% of cases).

· Double aortic arch.

· Left-sided superior vena cava (in 10% of cases).

· Hypoplasia of the pulmonary arteries.

· ASD.

Mention the common congenital heart diseases.

VSD, ASD of the secundum type, patent ductus arteriosus and Fallot's tetralogy are the common

congenital heart diseases, in order of frequency.

What are the CXR findings?

· Boot-shaped heart.

· Enlarged right ventricle.

· Decreased pulmonary vasculature.

· Right-sided aortic arch (in 30% of cases).

What do you know about the raussig-Bing syndrome?

In this condition the aorta arises from the right ventricle; the pulmonary trunk overrides both ventricles at

the site of an interventricular septal defect.

Etienne-Louis Arthur Fallot (1850-1911), Professor of Hygiene and Legal Medicine in Marseilles,

published his Contribution to the pathologic anatomy of morbus coeruleus cardiac cyanosis in 1888. The

tetralogy was first described by N. Stensen, Professor of Anatomy in Copenhagen, in 1672 (Fallot A.

Contribution a I'anatomie pathologique de la maladie bleue (cyanose cardiaque). Marseille Medical 1888;

25: 418-20).

Helen Brook Taussig (1898-1986) is the founder of American paediatric cardiology. She collaborated with

Alfred Blalock (1899-1964), a vascular surgeon, in the development of palliative surgery for Fallot's

tetralogy (JAMA 1945; 128: 189).