Conotruncal anamolies

Msn Pavan KumarNizam’s Institute of Medical

Sciences ,Panjagutta,Hyderabad,India.

[email protected]

Conotruncus Embryology & Anomalies

The conotruncus comprises collectively two myocardial subsegments, the conus and the truncus.

Conus is the myocardial segment between ventricle and semi lunar valves which gives rise to sub arterial coni.

Truncus is the fibrous segment between semi lunar valves and aortic sac which gives rise to great arteries.


Embryology1.Septation of conus and truncus.2.Rotation and absorption.3.Development of semi lunar valves.4.Important structures involved

a) Neural crest cells.b) Secondary heart field.

Congenital heart diseases d/t conotruncus

Genetic defects in Conotruncal


4 truncus and 2 conal cushions develop.Dextro- sinistro cushions of both conus and truncus fuse

to form Conotruncal septum.Intercalated cushions play an role in formation of semi

lunar valves


Embryology - Septation of conus and truncus.

Embryology - Septation of conus and truncus.


Because the cushions are dextro-superior and sinistro inferior in truncus and dextro-dorsal and sinistro-ventral in conus union forms a spiral septum than true lineal relation.

For convenience it is represented as linear structure

Aorta will be in connection with RV and PA with LV.There are two rotations one at conoventricular

junction and other at Conotruncal junction. Both rotations are counterclockwise around 110º


Embryology - Rotation and absorption.

Conoventricular rotation brings aorta in continuation with LV and PA with RV.

Conotruncal rotation brings the normal position of aorta in relation to PA ( left and posterior to PA)



Second most important thing is absorption of conus.Out of the two coni which ever remains persistent and

grows pushes the artery more anterior and superior direction bringing it in direct connection with RV.

In normal heart sub aortic conus is absorbed completely.



Septation at valvular level occurs in intercalated cushions leading to formation partial aortic and pulmonary valve.

The remaining part is formed by Conotruncal cushions.


Embryology – Semilunar valves.

Second heart field cells and neural crest cell play important role in development of conotruncus


Embryology – Important Structures For Development Of Conotruncus.

Conotruncal defects1. Truncus 2. TOF (with absent PV& PA)3. DORV4. DOLV5. D-TGA6. Conoventricular septal

defects7. Interrupted aortic arch

type B


Failure of aortopulmonary septum to Septation give rise to persistent truncus arteriosus.

TruncusConus


Truncus arteriosus.

Infundibular septum which arises from conal septum moves anteriorly and superiorly causing components of TOF


TOF:

Conoventricular rotation is based on which coni persists.

Artery with coni will be anterior and superior and connected to RV

If both coni are present both arise from RV - DORV


DORV

Type More prominent coni

Less prominent coni

VSD commited to

TOF(40%) Subpulmonic Sub aortic Aorta

VSD (15%) Subpulmonic Sub aortic Aorta

TGA(20%) Subaortic Sub pulmonic PA

Variants(DC<10%)

---- Both Both

Variants(NC<10%)

Both ---- Non committed


DORV

In DORV, rotation of great arteries driven by conal development that changes not the position of VSD.

In DOLV both coni are absent hence both arteries are posterior and arising from LV


DOLV


D - TGA

Absence of conal(Infundibular) septum leads to formation of malaligned , subinfundibular , subpulmonic VSD .


Cono ventricular septal defects.

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Conotruncal anamolies

Health & Medicine

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