Ventricular Ventricular Septum DefectsSeptum Defects

Nur Amalina bt Aminuddin Baki082012100067

IntroductionIntroductionNormal ventricle septum

formation Semilunar Valve FormationVSD

Tetralogy of FallotPersistent truncus arteriosusTransposition of Great VesselsValvular Stenosis

Normal Ventricle septum Normal Ventricle septum formationformationEnd of 4th week, two primitive

ventricles begin to expand, accomplished by continuous growth of myocardium outside and cont.diverticulation and trabecula formation on the inside

Medial wall merges muscular interventricular septum

Inferior endocardial cushion closes the foreman membranous part of interventricular septum

Semilunar Valves(SLV)Semilunar Valves(SLV)Partitioning of truncus almost

complete, primordia of SLV become visible as small tubercles on main truncus swellings.

One of each pair for pulmonary and aortic channel

Third tubercles appears opposite to the fused truncus swellings

Tubercles hollow out forming SLV

Ventricle septum Ventricle septum defects(VSD)defects(VSD)Involve membranous(more

serious) or muscular part of septum

VSD: Most common congenital cardiac malformation 12/10,000 births

Tertralogy of FallotTertralogy of FallotUnequal division of conus , resulting

from anterior displacement of conotruncal septumcardiovascular alterationNarrow right ventricular outflow region

(pulmonary infundibular stenosis)Large defect of interventricular septumAn overriding aorta Hyperthropy of right ventricular wall

Not fatal, only 9.6/10,000 births

Persistent truncus Persistent truncus arteriosusarteriosusConotruncal ridges fail to fuse and

descend towards ventricles0.8/10,000 birthsPulmonary artery arises some

distance above origin of undivided truncus

Accompanied by defective interventricular septum

Overrides both ventricles and receive blood from both side

Transposition of great Transposition of great vesselvesselConotruncal septum fail to follow

normal spiral course and run straight down

Aorta originates from RVPulmonary artery originates from LV4.8/10,000 birthsAssociated with membranous part

interventricular septum and open ductus arterious

DIGEORGE SEQUENCE DIGEORGE SEQUENCE Characterized by a pattern of

malformations that originates in abnormal neural crest developmentfacial defectsthymic hypoplasia parathyroid dysfunctioncardiac abnormalities involving the

outflow tract

Valvular stenosisValvular stenosisSLV fused ( 3-4/10,000 births) Valvular Stenosis of Pulmonary Artery

pulmonary artery patent oval foramen only outlet for blood from right ventricle

Ductus arterious only access route to pulmonary circulation

Aortic Valvular Stenosis Fusion of thickened valves left only a pinhole

openingNormal size of Aorta

• Aortic Valvular Atresia aorta, LV , LA underdevelopedopen ductus arteriosus

ConclusionConclusionTetralogy of Fallot unequal

division of conusPersistent truncus

arteriosusconotruncal ridges failure to fuse and descend

Transposition of Great Vesselsconnotruncal septum fail to follow spiral course

Valvular Stenosis fused SLV

ReferenceReferenceLangman’s Medical Embryology,

10th edition, TW Sandler