Saturday, November 20, 2010

Malpositions of the heart




Dextrocardia


Definition:


The cardiac apex lies in the right side of the chest.


Pathology:


The other viscera may show situs inversus totalis (All thoracic & abdominal viscera are inverted): In such cases the incidence of associated congenital heart disease is only 3 %.

Or situs solitus (Normal) or ambiguous (Indefinite): In such cases the incidence of associated congenital heart disease is 90 %.
In both types; l-loop of the ventricles (anatomical RV to the left) is usually present.


Associated conditions:

  • Congenital heart disease:
    • TGA.
    • Corrected TGA.
    • DORV.
    • VSD.
    • Single ventricle.
    • PS or pulmonary atresia.
  • Polysplenia, or asplenia.
  • Kartagener’s syndrome, which results from impaired ciliary movements and consists of
    • Situs inversus totalis.
    • Sinusitis.
    • Brochiectasis.


Isolated levocardia


Normal heart position is present, but with situs inversus (15 %) or ambiguous (85 %) of the viscera.
Associated anomalies include: Congenital heart diseases similar to those with dextrocardia, asplenia or polysplenia.


Mesocardia


Cardiac apex is present in the middle of the chest.
The heart may be normal, or it may have congenital anomalies.


Criss cross heart


This is also called upstairs-downstairs heart or superior-inferior ventricles:

Ventricles: RV is leftward & superior, LV is rightward & inferior and interventricular septum is horizontal. 
This anomaly results from exaggerated clockwise rotation of the heart in patients with l-loop of the ventricles.
AV connections: AV discordance in all cases.
VA connection:
Most patients have VA discordance with D or L Transposition, or DORV.
Few cases have VA concordance.
Associated conditions:
Most patients have PS & VSD.
Straddling of the mitral or the tricuspid valve is common, with stenosis and/or regurgitation.
Clinically: similar to TGA complexes.
Management: depends on the particular pathology present.


Ectopia cordis


The heart is present outside the thoracic cavity.
It is a very rare anomaly.


Thoracic form:
The heart is present on the anterior chest wall.
The apex usually faces upwards and may touch the chin of the child.
The vessels pass via a sternal defect to join the heart.


Abdominal heart:
The heart is present in the abdomen.
The vessels pass via a diaphragmatic defect to join the heart.


Asplenia syndrome


Pathology:


This syndrome is usually characterized by bilateral right-sidedness.
It is more common in males.


The anomalies include:
  • The liver is placed transversely across upper abdomen in > 50 %.
  • The stomach is left-sided in > 50 % of cases.
  • There is intestinal mal-rotation in two-thirds of the cases.
  • Renal anomalies are present in some.
  • Both lungs are tri-lobed.
  • Bilateral eparterial bronchi (The bronchi are higher in position than the pulmonary arteries).
  • Both atria have the morphology of RA.
  • Isolated Levocardia, Dextrocardia or Mesocardia may occur.
  • Bilateral SVC is present in most cases.
  • Coronary sinus is absent in nearly all cases.
  • Associated cardiac anomalies include: ASD, Single atrium, VSD, AVSD, Peripheral PA stenosis, TAPVD, TGA, DORV.
  • Howell-Jolley bodies are present in a stained smear of the peripheral blood.
  • Absent spleen: No splenic tissue anywhere is demonstrated by the isotopic scan.


Clinical picture:


Most patients present with cyanosis.
One third of them die within the 1st week, and 90 % within the 1st year.


Management:

  • Treatment of cyanosis, medically and by shunt procedures.
  • Continuous antibiotic prophylaxis, due to absence of the defensive function of the spleen.


Polysplenia syndrome


Pathology:


This syndrome is usually characterized by bilateral left-sidedness.
It is more common in females.


It includes the following anomalies:
  • The liver lies in the left side of the abdomen in 75 % of cases.
  • The stomach lies in the right side in two thirds of cases.
  • Mal-rotation of the bowel may be present.
  • Renal anomalies are present in some.
  • Both lungs are bi-lobed in most cases.
  • Bilateral hyparterial (Below the pulmonary arteries) bronchi.
  • Both atria are morphologically similar to LA.
  • PAPVD, with the left lung veins draining into LA & the right lung veins into RA.
  • Bilateral SVC is common.
  • Absence of the hepatic segment of IVC is common.
  • Isolated Levocardia, Dextrocardia or Mesocardia may occur.
  • Associated cardiac anomalies include: ASD, VSD, Single ventricle, AVSD, PS, Pulmonary atresia.
  • Radioisotopic scan demonstrates splenic tissue in both sides of the abdomen.

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