Left cardiac obstruction (without shunt)

Obstructions, i.e., constrictions of the flow path at various levels can also occur on the left side of the heart. Pure obstructions result in a massive supplementary load on the cardiac muscle because it must pump against elevated resistance. Partially, there are compensatory shunts without which survival would not be possible.


Aortic stenosis

Aortic stenoses occur relatively frequently and comprise 7% of congenital cardiac abnormalities. These are obstructions of the left ventricular outflow tract, i.e., the aortic valve and the ascending aorta.

In all its forms constriction of the left ventricular outflow tract gives rise to pressurestress of the left ventricle with compensation by a left ventricular hypertonia.

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Morphologically, according to the localization of the stenosis, 3 groups can be distinguished.
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Overview, according to the clinical picture, of the diagnostic possibilities as well as the therapy.


Aortic insufficiency

Aortic insufficiency is seldom found in newborns and is mainly a consequence of an operative intervention, e.g., from the balloon dilatation of an aortic stenosis.


Aortic isthmus stenosis (coarctatio aortae)

The region of the distal aortic arch near the ductus arteriosus inlet is called the aortic isthmus. A coarctation is a stenosis in the aortic isthmus region and it is encountered with a frequency of ca. 6% of all congenital cardiac abnormalities. Often dispersed ductus tissue, which contracts after birth, is found in sections of a stenosized wall.

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Depending on the site where the stenosis is located in relation to the ductus arteriosus, one distinguishes the following forms of aortic isthmus stenoses:

In the first two, the blood for the lower half of the body is still supplied postnatally by the ductus arteriosus. The stenosis is apparent only when the ductus closes and it comes to acute pressure stress of the left ventricle. In the third form the supply of blood for the lower half of the body comes only via collateral vessels like the intercostal or internal thoracic arteries. Accompanying abnormalities such as a bicuspid aortic valve, aortic stenosis, VSD and stenoses of the vessels that lead away from the aorta are very frequent.

Overview, according to the clinical picture, of the diagnostic possibilities as well as the therapy.


Interrupted aortic arch

While with aortic isthmus stenoses the continuity of the aortic arch is preserved, this is lost when the aortic arch is interrupted - a segment of the aortic arch is missing. This abnormality is relatively seldom, however.


Hypoplastic left cardiac syndrome

In the hypoplastic left heart syndrome, which comprises only 2% of all cardiac abnormalities, one finds a poorly developed (hypoplastic) left ventricle that is often only a few millimeters thick. The aortic and mitral valves are constricted (stenotic) or completely closed (atretic). Only the right ventricle functions normally and supplies the circulation system with blood. The arterial blood from the left atrium gets into the right atrium and ventricle via the foramen ovale that is kept open. The aorta ascendens that mostly ends blind at the valve is filled retrograde by the blood of the ductus arteriosus. In this way the coronary arteries that leave the proximal part of the aorta ascendens can also be supplied with blood.

Fig. 35 - Hypoplastic left ventricle

  1. Open ductus arteriosus
  2. Open foramen ovale
  3. Hypoplastic ventricle

Fig. 35

The left ventricle is hypoblastic. Through an open foramen ovale the blood gets to the right side and mixes with the O2 unsaturated venous blood. This left-right shunt via the foramen ovale as well as the right-left shunt via the ductus arteriosus are necessary for survival. Such children are cyanotic.