16.10 Pathologie



Inleiding


The formation of the heart is a very complex process - errors can occur at every step in its development. They lead to congenital disorders that, due to an incidence of 1 in 1000 newborns, belong to the most frequent birth defects. Chromosomal aberrations are also very frequently associated with heart abnormalities. In the future, it will probably be possible to trace even more congenital malformations back to genetic predispositions when the processes that lead to heart formation are better understood at the molecular level.

In the clinic 4 very frequent heart abnormalities dominate. They make up more than half of the ones that are encountered. They are:

  • VSD = ventricular septal defect (28%)
  • ASD = atrial septal defect (11%)
  • Pulmonary stenosis (9%)
  • PDA= persisting ductus arteriosus (9%)

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Compilation of some of the important diseases or syndromes that derive from heart abnormalities (etiology).



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In addition to pathological heart sounds obtained with a stethoscope, the following clinical signs can indicate cardiac abnormalities:

In infants:

  • Cyanosis of the child (due to a mixture of O2 saturated with O2 unsaturated blood)
  • Poor growth (the baby fails to gain weight)
  • Excessive sweating, mainly when drinking (a big effort for the child
  • Shortness of breath
  • Laziness at nursing (the baby often falls asleep while nursing due to the large effort it must expend)

In older children:

  • Limited somatic resilience
  • Low stamina
  • Tendency for infections


One can also subdivide congenital heart abnormalities according to location and hemodynamic effects. In case of an incomplete separation of the lungs and somatic circulation systems a shunt is formed. With each cardiac contraction the blood goes over from one circulation system to the other according to the different blood pressures in the two systems.

Cardiac abnormalities can thus be subdivided into the following three groupings:

  • Anomalies without shunt
  • Anomalies with left-right shunt (normally without cyanosis)
  • Anomalies with right-left shunt (with cyanosis --> mixed blood)

Besides auscultation (with the stethoscope) echocardiography is the most frequently applied diagnostic method for clinical examinations. Cardiac catheter examinations are indicated in complex cardiac abnormalities and before operations.

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In the heart various pressure relationships and O2 saturation values in the blood hold sway in a tight space (illustration)



Right cardiac obstruction (without shunt)


Obstructions, i.e. obstructions of the passages, can occur at various levels in the right side of the heart or in the pulmonary outflow path. Pure obstructions do not result in a mixing of the blood but a massive additional strain on the cardiac muscles because they have to pump against increased resistance.



Pulmonary stenosis (PS)


Isolated PS occurs with a frequency of 9% of all congenital cardiac abnormalities and, combined with other cardiac abnormalities, with a frequency of nearly 21%.

All forms lead to a hindrance of blood flow ejection from the right ventricle to the pulmonary artery. Depending on how big the stenosis is, a pressure stress and a compensatory hypertrophy of the right ventricle develop.

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Constrictions in the region of the right ventricular outflow or of pulmonary arteries can occur at various levels.

An
overview, according to the clinical pictures, of the diagnostic possibilities as well as the therapy.



Tricuspid stenosis


IIt is corrected by a commissurotomy (expansion) of the valve opening rims.



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