Saturday, June 19, 2010

Tetralogy of Fallot

Tetralogy of Fallot is treated surgically. A temporary operation may be done at first if the baby is small or if there are other problems. Complete repair comes later. Sometimes the first operation is complete repair. Placement of a BLALOCK-TAUSSIG SHUNT (BTS) is a 'closed-heart' procedure performed as a first stage to correct TOF. Placement of a shunt is usually a temporary measure designed to alleviate symptoms until such time that the patients is in better condition to undergo complete repair.

BTS (An incision is made on the side of the chest under the arm, extending up towards the scapula).

The significant problem in TOF is REDUCED blood flow into the lungs. This results in reduced oxygen delivery to the body.

The operations designed to increase blood flow into the lungs are called SYSTEMIC-PULMONARY SHUNTS. These are connections between aorta or one of its branches (the "systemic" arteries / subclavian artery) and the pulmonary artery. The principle underlying these shunts is that a portion of blood flow from the arteries will ne directed across the shunt into the pulmonary artery and its branches. This has 2 effects :

  • First, by increasing the total lung blood flow, the amount of oxygen available for distribution to the rest of the body is increased.
  • Second, the increasing amount of blood flowing into the pulmonary artery and its branches stimulates them to grow in size. The narrow portions may become wider. So, later, when an operation for total correction is performed, there is little or no obstruction to lung blood flow.

Patient who have had completely repair of this condition in infancy may present with particular problems.

Repair of the right ventricular outflow obstruction and enlargement of the pulmonary valve annulus may leave severe pulmonary regurgitation which may lead eventually to exertional dyspnoea.

The surgery itself has, until recently, required a right ventriculotomy (cutting into the right ventricle). this leave a scar that can be associated with cardiac rhythm abnormalities in later life. patients may present with palpitations or syncope.

Signs may include:
  • a median sternotomy scar,
  • a long diastolic murmur of pulmonary regurgitation and signs of right ventricular enlargement (parasternal impulse)
  • and later of tricuspid regurgitation (big v waves in the neck and a pulsatile liver).

Thanks to Dr Ngiu for asking us about BTS and how to know the patients had done the operation for TOF, any signs?

Sources :
Talley O'Connor Clinical Examination



alvisto said...

An image to make BTS more clear

Maybe the creator of this post can insert this pic ?

Nice post btw. :3

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