Malformations Associated With Right-to-Left Shunts And Clinical Features

Malformations Associated With Right-to-Left Shunts And Clinical Features In Full Detail

Heart defects associated with right-to-left shunting are characterized by early cyanosis. This is due to the fact that the low oxygenated blood from the right side of the heart enters the arteries directly. The two most important conditions associated with cyanotic congenital heart disease are Fallot tetralogy and large duct transposition.

Clinical consequences of acute systemic cyanosis include thickening of the fingers and toes (hypertrophic osteoarthritis), polycythemia, and paradoxical embolism.

Tetralogy Of Fallot

Fallot tetralogy cyanotic is the most common cause of congenital heart disease. It accounts for about 5% of all congenital heart defects. Four main features:

  • VSD
  • Right ventricular outlet obstruction (subpulmonary stenosis)
  • Elimination of VSD through the aorta
  • Right ventricular hypertrophy

All tetrahedral symptoms of Fallot are the result of high displacement of the posterior part of the infantibular septum, resulting in abnormal septum between the pulmonary trunk and the aortic root.


The heart is enlarged due to right ventricular hypertrophy and its shape is “boot”. The proximal aorta is dilated and the pulmonary trunk is hypoplastic. The left ventricular cavity is normal in size, while the right ventricular wall suddenly undergoes hypertrophy, sometimes exceeding the thickness of the left ventricle. VSD is usually larger and closer to the membrane portion of the intraventricular septum.

The aortic valve is located directly above the VSD (upper aorta) and is the main external site for blood from both ventricles. Obstruction of the right ventricular outflow is usually due to narrowing of the excretory duct (sub-pulmonary stenosis), but it may also be due to pulmonary valve stenosis or complete atresia of the valve and nearby pulmonary artery.

In such cases, a permanent PDA or a narrowed bronchial artery is the only way for blood to enter the lungs.

Clinical Features

The hemodynamic results of Fallot’s tetrad are shunting from right to left, reducing pulmonary blood flow, and increasing aortic volume. Medical severity largely depends on the degree of obstruction of pulmonary ejaculation. Even without treatment, some patients may survive to adolescence.

Thus, if the pulmonary obstruction is mild, the condition is similar to that of an isolated VSD, since the increase in pressure on the left side results only in shunting from left to right without cyanosis. Often, more severe levels of pulmonary stenosis cause early cyanosis. In addition, as the baby gets older and the heart size increases, the opening of the lungs does not expand proportionately, which causes it to develop.

The severity of stenosis. Fortunately, pulmonary outflow stenosis protects the pulmonary tract from excessive pressure and volume, so pulmonary hypertension does not develop and right ventricular failure is greatly reduced. However, patients with cyanotic heart disease such as hypertrophic osteoarthritis and polycythemia (due to hypoxia) as well as hypersensitivity.

Right-to-left shunting also increases the risk of infectious endocarditis and systemic embolization. Complete surgical correction is possible in the classic tetralogy of the fallopian tubes, but more difficult in pulmonary atresia.

Transposition Of The Great Arteries

Transfer of the large artery to the ventricle is an irregular contact with its vascular outlet. Embryological defects are abnormal formations of the trunk and orthopulmonary septa in which the aorta exits the right ventricle and the pulmonary artery exits the left ventricle. However, on the right, the relationship between the atria and the ventricles is normal.

The atrium joins the right ventricle and the left atrium empties into the left ventricle.

The active result is a separation of systemic and pulmonary circulation, a condition not compatible with postpartum life unless a shunt (such as VSD) allows oxygenated blood to reach the aorta. In fact, VVD occurs in about a third of cases. The main right ventricular hypertrophy is because this space acts as a systemic ventricle.

The left ventricle is hypoplastic, as it pumps blood only in the pulmonary circulation with low resistance. Some newborns with large arterial transfusions have a patent foramen oval, or PDA, which allows oxygenated blood to reach the aorta, but it closes. These babies usually need surgery in the first few days of life.

Clinical Features

The predominant manifestation is cyanosis, the diagnosis of which depends on the severity of the shunt, the degree of tissue hypoxia, and the ability of the right ventricle to maintain systemic pressure. Without surgery (even with permanent bypass surgery), most patients with incorrect arterial transplantation die within the first month of life.

However, better surgical techniques now allow for certain repairs, and these patients often survive into adolescence.

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