Tetralogy of Fallot – ToF

We’re now getting to a more complicated condition called the Tetralogy of Fallot – or ToF, for short. The diseases discussed until now had just one abnormality in the heart – Atrial Septal Defect (ASD) or Ventricular Septal Defect (VSD) or Patent Ductus Arteriosus (PDA).

As the name tetralogy implies, there are FOUR abnormalities combined together in this complex heart defect. ToF is also commonly called the “blue-baby” disease.

In this article, you’ll learn:

  • What are the components of ToF?
  • Why is it called “Blue Baby Disease”?
  • What exactly happens in ToF?
  • What is a “cyanotic spell”?
  • What happens if ToF is left uncorrected?
  • What are the surgical options?
  • How is a single stage intra-cardiac repair done?
  • Variations in ToF needing modified repair
  • What is an “outflow patch”?
  • When is an intracardiac repair NOT possible?
  • What are the palliative operations for ToF?
  • The Blalock-Taussig shunt
  • Other systemic-pulmonary shunt procedures
  • What is the outcome after a total correction operation?
  • What is the future course after a shunt procedure?

Basics of Tetralogy of Fallot

What are the four components of ToF ?

1. The first is a Ventricular Septal Defect – or VSD.

2. Next is a narrowing of the Pulmonary Valve, which guards the junction of the right ventricle with the pulmonary artery. This narrowing is called Pulmonary Stenosis (PS).

3. The third feature is a thickening of the wall of the right ventricle (RV). This increases the strength of the right ventricle and helps it pump blood more forcibly. This thickening is called RV Hypertrophy.

4. And the last component is an over-riding aorta.

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Coarctation of the Aorta – CoA

You have read something of congenital heart defects inside the heart. Now let us consider a defect that is outside the heart itself, in one of the great arteries of the body – the aorta.

What is COARCTATION of the aorta ?

Coarctation of the aorta (CoA) is an area of localized narrowing of the large artery called the aorta. (“Coarctatio” – Latin : a drawing or pressing together). The narrowing may be caused by a “shelf” of tissue inside the blood vessel which reduces its area. Alternately, it may be caused by under-development of a portion of the aorta itself, which causes a longer area of reduced diameter.

Where does CoA occur ?

The narrowing that occurs in CoA is most commonly seen at a portion called the ISTHMUS.

But what is the isthmus ?

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