1. Cardiac Malpositions
Presenter : dr anish

2. Cardiac Malpositions Terminology Looping of heart
anomalous location of the heart
Estimated prevalence : 0.10 per 1,000 live births

3. Terminology
Cardiac malposition : An abnormal intra-thoracic position of the heart.
Situs : Site or position of the viscera or atria.
Solitus : Normal or usual.
Situs solitus : Normal position
Depends on abdominal Situs and position of heart in the thorax . two logical Situs these are Situs Solitus (Normal) and its opposite Situs Inversus

4. Situs inversus: Mirror image /
inversion or right/left reversal
of visceral or atrial site or position
Situs ambiguous : uncertain or
indeterminate visceral or atrial
position because of symmetric
or indeterminate anatomy bilaterally

5. Terminology The intrathoracic Cardiac position
( levocardia / dextrocardia / mesocardia)
Dextrocardia : the location of the heart in the right hemithorax with the base to apex axis to the right
Mesocardia : cardiac base to apex axis directed to the midline of the thorax or with ventricular apices equally directed to both right and left sides
Levocardia : cardiac location in the left hemithorax with the apex (base to apex axis) pointing to the left. Considered as cardiac malposition with situs inversus and situs ambiguus .

6. abdominal Situs and position of heart in the thorax
abdominal Situs and position of heart in the thorax. There are two logical Situs these are Situs Solitus (Normal) and its opposite Situs Inversus. So they are two logical cardiac positions Levocardia and Dextrocardia.

7. Terminology
Displacement : An abnormal cardiac position secondary to eventration of a hemidiaphragm, agenesis of a lung, or congenital complete absence of the pericardium

8. Terminology
Ectopia cordis : Location of the heart outside the thoracic cavity

9. Terminology
Great arterial designations: The ascending aorta and pulmonary trunk defined by their ventricle of origin and by their morphology
Heterotaxy : Greek “heteros” : different and “taxis” : arrangement
Isomerism : Greek “isos” : equal and “meros” part.
The similarity of bilateral structures that are normally dissimilar
Chamber designations: Right and left
Chamber designations: Right and left, as in right and left atrium and right and left ventricle.

10. Looping of heart D-loop: Rightward (“dextro”) bend.
L-loop: Leftward (“levo”) bend
Cardiac looping in late fourth week and early fifth week
The straight heart tube of the embryo forms the left ventricle of the definitive heart. Looping is the consequence of the addition of new material at the arterial pole of the developing heart

11. Looping
 heart tubes forms constrictions defining separate components of the heart (cranial to caudal): Bulbus cordis, ventricle and atrium.
The bulbus cordis is continuous with the truncus arteriosus which connects cranially to the aortic sac.
The primitive atrium is still paired and connects caudally to the paired sinus venosus. Both the atrium and sinus venosus are outside the pericardial sac

12. The straight heart tube elongates with simultaneous growth in the bulbus cordis and primitive ventricle.
This forces the heart to bend ventrally and rotate to the right, forming a C-shaped loop with convex side situated on the right.

13. atrium and sinus venosus become dorsal to the heart loop
The ventricular bend moves caudally and the distance between the outflow and inflow tracts diminishes.
atrium and sinus venosus become dorsal to the heart loop
The atrial and outflow poles converge and myocardial cells are added, forming the truncus arteriosus.
The embryonic straight heart tube initially bends to the right (d-loop), then moves to the left until the ventricular portion occupies a normal left thoracic position

15. Concordance Latin “concordare” : to agree.
Atrioventricular concordance:
Connection of a morphologic atrium to a corresponding morphologic ventricle.
Ventriculoarterial concordance:
Connection of a morphologic right ventricle to a pulmonary trunk and a morphologic left ventricle to an aorta.
A loop that agrees with the visceroatrial situs

16. Discordance Latin “dis” : apart / Inappropriate.
Atrio-ventricular discordance:
A morphologic RA to LV LA to RV.
Ventriculo-arterial discordance:
A morphologic RV gives rise to the aorta, and LV to the pulmonary trunk
Double discordance:
Atrio-ventricular discordance together with ventriculo-arterial discordance.
The result is physiologically correct circulatory flow.

17. Transposition of the great arteries:
Each great artery arises from an anatomically discordant ventricle
Malposition of the great arteries:
Abnormal spatial relations of the aorta and pulmonary trunk to each other.
Each of the abnormally related great arteries arises above the anatomically correct ventricle.
Inversion : Mirror imagery

18. does not address other lesions discussed in chapters dealing with double-inlet ventricles, double-outlet ventricles, or single-outlet hearts

20. Situs solitus with Dextrocardia
Isolated dextrocardia with AV concordance and NRGA
The base-to-apex axis points to the right, so the right hemidiaphragm is lower than the left
The embryonic straight heart tube initially bends rightward (d-loop) but fails to move into the left chest.
Congenital heart defects:
ventricular septal defect
left SVC to the coronary sinus
coarctation of the aorta
secundum atrial septal defect
anomalous pulmonary venous connections
complete AV septal defect
Clinical presentation depends on associated lesions
the lungs and abdominal viscera are normally positioned
the ascending aorta and aortic knuckle are normally located
the descending aorta runs its normal course along the left side of the vertebral column,

21. Radiographic findings
ECG
atrial activation is normal, and the P-wave frontal plane axis is 70 to 80
the frontal plane QRS axis exhibits a rightward shift or right-axis deviation
a gradual and progressive reduction in the QRS R-wave voltage is observed
Radiographic findings
heart positioned in the right chest.
Volume overload lesions - evidence of pulmonary hyperperfusion.
Bronchial branching patterns are normal.
Visceral situs solitus is recognized by the left-sided stomach bubble and right-sided liver.

22. Corrected Transposition of the Great Arteries
Isolated Dextrocardia with AV and VA Discordance and Left Anterior Aorta
most common form of dextrocardia
High incidence of associated cardiac anomalies
VSD and PS
DILV with hypoplastic subaortic right ventricle.
Pulmonary atresia,
complete AV septal defect,
mitral atresia (right AV valve),
tricuspid regurgitation (left AV valve) with Ebstein anomal “like malformation,
anomalous systemic and pulmonary venous connections (especially with a persistent L-SVC to the RA or directly to the LA with an unroofed coronary sinus) .

23. X-RAY & ECG findings are similar to those observed in dextrocardia with NRGA
CLUE TO TGA :
the initial qR wave of the QRS complex is abnormally directed to the left
consistent with abnormal septal depolarization associated with AV discordance.

24. Situs inversus with Dextrocardia
incidence 1 in 8,000
The thoracic and abdominal viscera are mirror images of normal
morphologic right bronchus is concordant with the morphologic right atrium and a trilobed lung,
SIGNIFICANCE :
usually occurs with a structurally normal heart
The pain of angina pectoris is in the right anterior chest and radiates to the right shoulder and right arm.
The pain of appendicitis is in the left lower quadrant.
Biliary colic is assigned to the left upper quadrant.

25. Situs inversus with Dextrocardia Inverted Normally Related Great Arteries (Left Posterior Aorta)
Situs inversus totalis with persistence of normal AV and VA connections
CHD :
VSD
TOF
pulmonary atresia
complete AV septal defect
OS ASD.
X-ray : visceral situs inversus and dextrocardia.
Ecg :
Atrial and ventricular voltage changes that are inverted from normal.
The P-wave axis is directed to the right and inferiorly because of atrial inversion
2. the atria, ventricles, and great arteries are all inverted from their normal location and spatial relationships
Common form of dextrocardia in normal hearts and situs inversus totalis

26. Situs Inversus with Dextrocardia, Atrioventricular Concordance, and Ventriculoatrial Discordance with Left Anterior Aorta
Inverted form of complete TGA
The hemodynamics and physiology identical to TGA
ECG :
inverted P-wave axis because of the atrial inversion
more evidence of associated right and left ventricular hypertrophy because of transposition physiology

27. Situs Inversus with Dextrocardia Atrioventricular and Ventriculoatrial Discordance, with Right Anterior Aorta
inverted form of corrected TGA
Rare
the segmental cardiac connections theoretically are physiologically correct
associated severe anomalies results in profound hemodynamic impairment

28. Situs Inversus with Dextrocardia, AV Discordance, and VA Concordance with Inverted NRGA
Represents the inverted form of isolated ventricular inversion
hemodynamics are comparable with those of complete TGA
extremely rare
cardiac abnormalities
common atrium
common AV valve
severe right ventricular hypoplasia.

29. Isolated Levocardia Normal position and base to apex cardiac axis
implies that either situs inversus (3% to 14% )or situs ambiguus is present.
AV and VA discordance or double-outlet right ventricle with anterior right aorta : inverted form of corrected TGA
AV discordance was present with atrial situs inversus : ventricular noninversion / d-loop
The lungs and abdominal viscera are mirror images of normal.
Associated with complex
congenital heart disease

30. Mesocardia
longitudinal axis of the heart lies in the midsagittal plane, with the heart possessing no distinct apex.
very low incidence
Mostly with situs solitus
consisted of
normal hearts
VA discordance with AV discordance (corrected TGA )
VA discordance without AV discordance (complete transposition of the great arteries)
Mesocardia with a d-bulboventricular loop in situs solitus is a variation of normal

32. Physical examination Percussion :
Cardiac borders
Right sided liver
Left-sided stomach
Cardiac dullness in supine position but turned moderately to the left and then moderately to the right, because the heart decreases to the side of the base-to-apex axis
In situs solitus with a right thoracic heart, the apical right ventricle retracts, and the systemic morphologic left ventricle generates an outward systolic impulse adjacent to the lower right sternal border

33. Auscultation
signs should be compared along the left and right sternal borders and at the cardiac apices,
alternating from side to side to compare analogous right and left thoracic sites.
Splitting of the second sound is prominent in the second intercostal space on same side of cardiac situs

34. ECG
The direction of the P wave is determined by atrial situs unless the atrial pacemaker is ectopic
In situs solitus, atrial depolarization from a right sinus node results in normal P- wave axis.
In situs inversus, atrial depolarization is initiated by a left sinus node, so P waves are inverted in leads 1 and aVL and upright in lead aVR.
A left atrial ectopic rhythm is indicated by negative P waves in lead 1 and isoelectric or negative P waves in left precordial leads.
The Valsalva maneuver transiently returns an ectopic atrial focus to the right sinus node.
More distinctive but less common is a
Dome and dart P wave in lead V1/2 :
a left atrial ectopic focus irrespective of atrial situs

35. ECG
Situs inversus with Dextrocardia: reversed ventricular activation and reversed repolarization.
lead 1: QRS negative & the T wave inverted,
lead aVR resembles aVL and vice versa,
right precordial leads resemble leads from corresponding left precordial sites.
Septal Q waves appear in right precordial leads because septal depolarization is from right to left.
The electrocardiogram can be “corrected” by reversing the limb leads and recording chest leads from the right precordium

36. ECG
situs solitus with dextrocardia : depolarization in the frontal plane is counterclockwise
Q waves in leads 1 and aVL.
prominent R waves in leads V1and V2
prominent RS complexes in most of the remaining right precordial leads.
Normal left-to-right septal depolarization results in Q waves at standard left precordial sites
For “correcting” : limb leads unchanged, chest leads recorded from right precordial sites.
Correcting : because atrial situs is normal and the base-to-apex axis points to the right

37. Chest x-ray The first identify the orienting letters L and R.
Situs dermination
Establish the cardiac axis
The relative levels of the 2 hemidiaphragms
Identify concordant bronchial morphology
The ascending aorta is convex at the left basal aspect of the heart
From the radiologic point of view, that is all that is needed to recognize complete situs inversus
Situs inversus with a right thoracic heart is missed if the film is inadvertently reversed when read, because the x-ray then appears “correct.”
LEVEL of hemidiaphragms determined by the location of the cardiac apex, not by the location of the liver.
the descending thoracic aorta runs a course parallel to the left border of the vertebral column

38. Sequential segmental analysis
I: Cardiac position and apex orientation
II: Atrial arrangement
III: Atrioventricular connection
IV: Ventriculoarterial connections
V: Associated malformations and function of segment

39. Echocardiography with colour flow imaging Analysis
A segmental sequential review of all structures involved by the congenital anomalies
Sequential attention to independently addressed six segments, and position or malposition of the heart and abdominal viscera
Systemic and pulmonary veins
Atrial situs
AV connection
Ventricles and infundibulum
VA connection
Great arteries and ductus arteriosus

40. Atrial and visceral situs
Atrial and visceral situs are generally considered together because they are usually concordant
Systemic and pulmonary venous connections play a key role in the assessment of atrial situs.
  1. Caval position and connection   2. Hepatic veins   3. Coronary sinus   4.Pulmonary venous connection
Pulmonary venous connections often define the left atrium, and the suprahepatic inferior vena cava (IVC) often defines the right atrium
Visceral (abdominal) situs is determined by the sidedness of the liver and stomach
venous connections and visceral situs may not necessarily agree with the apparent atrial situs in situs ambiguous
The pancreas and spleen are generally located on the same side of the vertebral column as the stomach

41. RA : Receives suprahepatic segment of the IVC as a reliable marker for the morphologic right atrium, because embryologically, the sinus venosus is incorporated into the right atrium, coronary sinus . dilation of the coronary sinus may signal an anomalous venous connection, and if possible, unroofing of the coronary sinus should be ruled out, which if undetected could lead to residual atrial shunting after repair. SVC not reliable
LA : Receives pulmonary veins

42. The relationship between septum primum and septum secundum is the most reliable determinant of atrial situs
Morphologic right atrium
The inferior rim of septum secundum
Best seen by echocardiography as the
superior limbus of the fossa ovalis
Morphologic left atrium
The remnant of septum primum
best seen by echocardiography as the
valve of the fossa ovalis.

44. Atrioventricular Connections and Atrioventricular Valve Morphology
Commitment (AV malalignment—overriding, crisscross)
Insertion (chordal attachment—straddling)
Leaflet numbers
Papillary muscles (position, number, abnormality—parachute)
Leaflet abnormalities (cleft, thickening—stenosis)
Tricuspid valve
Mitral valve
   Septal chordal attachments
   No septal chordal attachments
   Low septal annular attachment
   High septal annular attachment
   Triangular orifice (midleaflet)
   Elliptical orifice (midleaflet)
   Three leaflets
   Two leaflets
   Several papillary muscles
   Two large papillary muscles
   Empties into right ventricle
   Empties into left ventricle

45. Ventricular Situs and Morphology
the cardiac base to apex axis
ventricular locations, relationships, and morphology
Cardiac position (levocardia, dextrocardia, mesocardia)  Ventricular relations (anterior, posterior, superior, inferior, right, left)  Papillary muscles (two discrete versus multiple irregular)
Right ventricle
Left ventricle
   Large apical trabeculations
   Small apical trabeculations
   Coarse septal surface
   Smooth upper surface
   Septal and parietal bands
   No septal or parietal band
   Receives tricuspid valve
   Receives mitral valve
   Tricuspid-pulmonary discontinuity
   Mitral-aortic continuity
   Muscular outflow tract (infundibulum)
   Muscular-valvular outflow tract
   Crescentic in cross section
   Circular in cross section
   Thin free wall (3-5 mm)
   Thick free wall (12-15 mm)

46. Great Artery Relations
Commitment (AV malalignment—overriding, crisscross)
Insertion (chordal attachment—straddling)
Leaflet numbers
Papillary muscles (position, number, abnormality—parachute)
Leaflet abnormalities (cleft, thickening—stenosis)
Eight basic types of great artery relationships are possible based on the aortic and pulmonary valve positions at the level of the semilunar valves
Right posterior aorta (normally related)
Right lateral aorta (side by side)
Right anterior aorta (d-malposed)
Directly anterior aorta
Left anterior aorta (l-malposed)
Left lateral aorta (left side by side)
Left posterior aorta (inverted normal)
Directly posterior aorta

47. Standard subcostal view 

48. Cardiac position
1 location : most of the cardiac mass left / right / midline
Levoposition or dextroposition or mesoposition
2. cardiac base to apex axis in subcostal four-chamber view

49. liver, hepatic veins, inferior vena cava (IVC), stomach, spleen, and abdominal aorta are obtained
 Situs inversus with dextrocardia is identified by the left atrium to the right of the aorta, the right atrium to the left of the aorta, the aorta to the right of the spinal column
In isomerism, the great vessels lie to the same side of the spine. In left isomerism, the inferior vena cava lies posterior to aorta and is interrupted and continued via a hemi-azygos vein in majority of cases. In right isomerism, the IVC is anterior to the aorta.

50. The visceral situs is considered ambiguous because it does not conform to the classical patterns of situs solitus or inversus
Their positions and venous connections can and must be accurately defined before corrective surgical procedures can be performed
splenic status by locating the stomach and interrogating the area posterior and lateral to the stomach denser echocardiographic appearance than the liver and its comma-shaped curvilinear splenic vein
The positions of the liver, stomach, IVC, and aorta must be individually described
Polysplenia : interruption of suprahepatic portion the IVC with azygous continuation, the hepatic veins will connect directly to the atrium and a midline location of abdominal aorta
Atrial and visceral situs inversus. Subcostal short-axis scan of the abdomen provides right-to-left spatial orientation

51. bilateral superior vena cavae direct to the ipsilateral atrium, interruption of the IVC with azygous or hemiazygous continuation to the superior vena cava (SVC), and various anomalous pulmonary venous connections
Direct pulmonary venous connections to the ipsilateral atrium, as well as complete or partial connections to the right or left superior vena cava

52. Pulmonary situs defined by the relationship of the pulmonary arteries to their adjacent bronchi
In a morphologic right lung, the pulmonary artery travels anterior to the upper lobe and intermediate bronchi. In contrast, a morphologic left lung is characterized by a pulmonary artery that courses over the main bronchus and posterior to the upper lobe bronchus
the distance from the carina to the origin of the upper lobe bronchus is 1.5 to 2 times greater for the morphologic left lung than for the right lung

53. Cardiac segments are evaluated not only according to morphology but also in terms of spatial orientation
the position and orientation of the ventricular septum determine the location of the ventricular chambers
levocardia, therefore, the ventricles are right anterior and left posterior.
in dextrocardia they usually are right posterior and left anterior
Mesocardia is characterized by a vertical midline septum

54. Echo modified from the right or left parasternal and subcostal positions to adequately delineate VA connections and great artery relationships
Parasternal long- and short-axis scans are particularly helpful in determining concordant, discordant, or double-outlet connections
suprasternal scans should be obtained to assess the proximal pulmonary and aortic arch anatomy. The aortic arch should be determined as right or left sided and the brachiocephalic branching pattern defined.
position of the aorta is described relative to the pulmonary trunk
right posterior aorta

55. Situs Ambiguus
right atrial (asplenia) or left atrial (polysplenia) isomerism
Dextrocardia with situs ambiguus was the most common

56. Heterotaxy with right isomerism
Greek “heteros”: different and “taxis”: arrangement
Isomerism (from the Greek “isos,” equal)
similarity of bilateral structures that are normally morphologically asymmetric
Strong concordance between a morphologic right bronchus, a trilobed right lung, and a morphologic right atrial appendage
In right isomerism, the bronchi are symmetric morphologic right, the lungs are trilobed, and the atrial appendages exhibit right morphologic features.

57. Situs ambiguus with asplenia
Cardiac :
The sinus nodes are paired because bilateral superior vena cavae are attached to bilateral morphologic right atria.
The P-wave axis is normal because the right sinus node is usually the dominant atrial pacemaker
The atrioventricular conduction system is equipped with 2 nodes often connected by a sling of tissue
Supraventricular tachycardia is attributed to reentry between paired atrioventricular nodes.
relatively consistent relation between the type of isomerism and the type of congenital heart disease
common atrium,
common atrioventricular valve,
morphologicsingle ventricle,
functional single ventricle (hypoplasticright or left),
pulmonary stenosis or atresia,
absent coronary sinus,
total anomalous pulmonary venous connection
bilateral ductus arteriosus.
Ventricular and great arterial connections are usually discordant.
Asplenia is accompanied by serious recurrent infections because of the many immunologic functions of the spleen.

58. Noncardiac midline abnormalities
tracheoesophageal fistula, meningomyelocele, encephalocele, cerebellar agenesis, cleft lip, cleft palate, and horseshoe kidney.
Lungs : bilateral morphologic right bronchi, bilateral trilobed lungs
Abdomen :
The spleen is the only organ that is left-sided from its inception, because it develops in the left side of the dorsal mesogastrium.
A relation exists between right isomerism and asplenia
5% of cases, however, a normal-sized spleen resides in the right upper quadrant.
Howell-Jolly bodies and Pitted red cells in peripheral blood smears
A wandering spleen can be mistaken for absence
Gastrointestinal disorders include biliary atresia and intestinal malrotation, transverse liver

59. Asplenia / Ivemark syndrome
normal birth weight
male predominance
Neonatal cyanosis is invariable, conspicuous, and often evident in the first 24 hours
Survival is determined largely by coexisting congenital heart disease and noncardiac disorders
Most deaths occur within the first few months

60. X-ray : discloses a transverse liver, bilaterally symmetric bronchi
overpenetrated chest x-ray to determine whether the bronchi are symmetric right or symmetric left
Thoracic echocardiography identifies morphologic right and left atrial appendages
Abdominal USG discloses a transverse liver, an aorta that is anterior to or on the same side of the spine as the inferior vena cava, and hepatic veins that drain into the inferior cava as it joins a right-sided atrium. A spleen cannot be detected.

61. Heterotaxy with left isomerism:
more prevalent in women
bilateral morphologic left bronchi, bilateral morphologic bilobed lungs, bilateral morphologic left atrial appendages, bilateral superior vena cavae attached
to bilateral morphologic left atria, an absent or atretic
sinoatrial node, common atrium, common atrioventricular valve, atrioventricular septal defect, and partial anomalous pulmonary venous connection.
The pulmonary veins can be connected in a symmetric fashion, 2 to the right-sided atrium and 2 to the left-sided atrium
but it is questionable whether this should be considered partial anomalous drainage

62. polysplenia syndrome
The most distinctive and therefore the most diagnostically useful clinical feature is inferior vena caval interruption with azygous continuation, in which the suprarenal segment of the inferior cava is absent, and the infrarenal segment continues as the azygos or hemiazygous vein
Fetal complete heart block is presumptive evidence of in utero left isomerism
Intrauterine loss for fetuses with left isomerism is greater
Polysplenia characterized by a cluster of multiple splenules

63. Morbidity and mortality are determined by coexisting cardiovascular malformations and by noncardiac anomalies, which are usually gastrointestinal(malrotation, biliary atresia, esophageal atresia and congenital short pancreas)
20% die as neonates; 50% do not survive adolescence
vena caval connections are necessarily to a morphologic left atrium, so the sinus node is absent or hypoplastic. The atrial pacemaker is therefore ectopic, and the P-wave axis is abnormal. The ectopic atrial pacemaker can shift from 1 site to another or may fire slowly (ectopic atrial bradycardia). Atrial fibrillation and atrial flutter are occasional.
Complete atrioventricular block occurs in approximately 1 in 5 cases
blocked at the level of the penetrating bundle, resulting in nodoventricular discontinuity and a narrow QRS interval

64. transverse liver is accompanied by symmetric left bronchi,
heart is usually left sided. The stomach tends to be on the side opposite the descending aorta. Inferior vena caval interruption with azygous continuation is best identified on the frontal chest x-ray
The aorta and inferior vena cava lie anterior to or on the same side of the spine.
When there is inferior vena caval interruption with azygous continuation, hepatic veins connect directly to the atrium without joining the inferior cava

65. Lower incidence of associated pulmonary outflow tract obstruction and a more frequent occurrence of bilateral pulmonary venous connections to the ipsilateral atrium
common-inlet ventricle of right ventricular morphology and double- outlet right ventricle
Most common complex : dextrocardia, atrial situs ambiguus, ventricular inversion, and VA concordance with left posterior aorta.
Suggested situs inversus and polysplenia with dextrocardia may be interrelated etiologically and embryologically
2nd most common : dextrocardia, situs ambiguus, ventricular inversion, and VA discordance with left anterior aorta

66. Treatment depend on the specific lesion encountered
conotruncal abnormalities (TGA/DORV), surgical correction
two-ventricular-type repair such as an arterial switch procedure (Jatene, Kaye–Damus–Stansel, or Aubert procedure), or
ventricular septal defect (VSD) closure connecting the systemic ventricle to the aorta, transsection of the pulmonary artery, and establishment of pulmonary ventricle to pulmonary artery continuity with an extracardiac conduit.

67. complex malformations associated with situs ambiguous
common atrium with common-inlet single ventricle or unbalanced ventricles, and complex malformations associated with criss-cross AV relations and severe AV valve straddling
surgical palliation directed toward function as a single ventricle such as with systemic–pulmonary artery shunts, Glenn-type shunts, bidirectional cavopulmonary shunts, and finally the modified Fontan procedures
special efforts must also be directed toward surgical establishment of appropriate venous connections or relief of venous stenosis
Medical management of complications of progressive hypoxia and polycythemia, progressive ventricular fibrosis, and ventricular failure, stroke, and brain abscess associated with such lesions