ECHO : SEGMENTAL APPROACH Dr Binjo J Vazhappilly SR Cardiology MCH Calicut
Segmental Approach to Imaging Congenital Heart Disease (CHD) • Systematic and sequential method to describe the cardiac segments and connections. • Three cardiac segments : atria , ventricle and great vessels. • Connections : specific relationship between the segments .
Determine visceroatrialsitus • Situs refers to spatial arrangement of the viscerae . Three types of visceroatrialsitus • S – solitus(normal arrangement) • I – inversus(or the mirror-image arrangement) • A - ambiguus • Situsambiguus: defined as an abnormality in which thoracic and abdominal organs are positioned with respect to each other, in such a way that it cannot be clearly lateralized.
Cardiac Position & Orientation • Position of the heart in the chest with regard to its location and orientation of its apex. Location of heart in the chest • Levoposition : to the left • Mesoposition : central • Dextroposition : to the right Cardiac orientation is the base to apex orientation of heart • Levocardia : apex directed to left of midline. • Mesocardia : apex oriented inferiorly in the midline • Dextrocardia: apex directed to right of midline.
Atrial Morphology The right & left atria are identified morphologically by their respective atrial appendages and veins emptying into them. Left Atrium Narrow, fingerlike posterior appendage . LA receives all 4 pulmonary veins Septum primum lies on LA side . LA is smooth with fewer trabeculations Right Atrium • Triangular, broad based, anterior appendage . • Receives IVC, SVC & coronary sinus. • Septum secundum (limbus of fossaovale) lies on RA side. • CristaTerminalis is in RA.
AtrialSitus • AtrialSitusSolitus (S) • AtrialSitusInversus (I) • AtrialSitus Ambiguous (A) Right isomerism (bilateral right atria) or Left isomerism (bilateral left atria).
Ventricular Looping • Embryonic heart is a linear tube with bulbuscordis (future RV ) being cephalad to the developing left ventricle (LV) . • In normal development the tube bends over on itself to right forming a D-loop resulting in positioning of the bulbuscordis to the anatomic right of the left ventricle • Folding to left results in L-loop with the morphologic right ventricle being to the left of the morphologic left ventricle
D Loop L Loop
Identification of the ventricles AV valve morphology directly correlates with ventricular type Tricuspid Valve ⇒ RV • Septalchordal attachments • Apical septal annular attachment • 3 leaflet • Multiple small papillary muscles • Triangular orifice Mitral valve ⇒ LV • No septalchordal attachments • Basal septal annular attachments • 2 leaflet • 2 large papillary muscles • Elliptical orifice.
RV Morphology • Large apical trabaculations • Coarse septal surface • Moderator bands • Cresentic in cross section • Tricuspid – pulmonary discontinuity
LV Morphology • Small apical trabeculations • Smooth upper surface • No moderator band • Mitral – Aortic continuity
Atrio-ventricular Connections • Concordant ( Normal : RA to RV & LA to LV) • Discordant ( RA to LV & LA to RV) • Univentricular AV connections Absent AV connection Common AV valve Double inlet connections
Univentricular AV Connections • Absent AV connection (right / left) Tricuspid / mitral atresia • Common AV valve With single ventricle • Double inlet ventricle Connection of both AV valve to the same ventricle Anatomically left Anatomically right Undetermined (rudimentary chamber always present)
Univentricular AV connections Absent Rt AV Connection Absent Lt AV connection
Univentricular AV connections Double inlet : RV Morphology Double inlet : LV Morphology
Overriding & Straddling • Overriding : Biventricular emptying of AV Valve or biventricular origin of a semilunar valve. • Straddling : Chordae or papillary muscle of the valve attach to contralateral ventricle. Involve AV Valves and requires presence of VSD.
Arterial Morphology • Aorta : artery that gives rise to the coronary arteries and the brachiocephalic vessels. • Pulmonary artery : branches into two but does not give rise to any vessels.
Ventriculo-Arterial Connection • Concordant : Aorta connected to LV and pulmonary artery to RV . • Discordant : Aorta connected to RV and pulmonary artery to LV . • Double Outlet : Both great arteries arise from a single ventricle. • If more than 50% of an artery overrides a ventricle it is said to be committed to it.
Commitment • Commitment describes possible abnormalities of flow through valves into ventricles and great vessels. • In TOF, atria, AV valves & ventricles are positioned normally and concordant. Aorta overrides a VSD and is doubly committed to both ventricles. • In univentricular heart both AV valves are usually doubly committed to the single ventricle.
Ventriculo-arterial connections • Concordant (normal) Ventricular septal defect, tetralogy of Fallot • Discordant Transposition • Double outlet ventricle With subaortic VSD subpulmonary VSD doubly committed VSD non-committed VSD • Common arterial trunk
Conus • Subpulmonary: Absence of subaorticinfundibular free wall, found in normal heart. • Subaortic: Absence of subpulmonaryinfundibular free wall, found in D-loop TGA. • Bilaterally present : In double outlet RV , but rarely in TGA. • Bilaterally Absent: In double outlet LV.
Relation b/w semilunar Valves • Solitus : Aorta posterior and to right. • Inversus : mirror image : Aorta posterior and to left • D-malposition : aortic valve anterior and to the right. • L-malposition : aortic valve anterior and to the left. • Anterior malposition : aortic valve anterior in the middle. • Parasternal and high parasternal short axis and subcostal short axis views are used to recognize the positions of AV and PV.
Normal PSX Suprasternal long and short axis
Assessment of Associated Anomalies Abnormalities in each segment should be assessed • Septal defects • AV valve abnormalities like Ebstein’s • Outflow tract stenosis • Aortic arch branching and sidedness • Pulmonary artery and branches • PDA • Coronary abnormalities
LV outflow Subaorticmembrane Supravalvular AS
Sequential Segmental Approach • Identify situs of the thoraco-abdominal organs. • Determine cardiac position within thorax. • AtrialSitus. • Ventricular Situs. • Atrioventricular connection and alignment. • Ventriculo-arterial connection and alignment. • Conal (infundibular) anatomy. • Relationship between the great arteries. • Description of associated malformations
Segmental Expression 1 . Visceroatrialsitus : S , I or A. 2 . Ventricular situs : D or L 3 . Position of great vessels : S , I , D , L or A • Normal : S , D , S • SitusinversusDextrocardia : I , L , I • D TGA : S , D , D • D TGA with situsinversus : I , L ,L • L TGA with situssolitus : S , L , L
Interrupted IVC is seen in • Situsinversus • Situssolitus • Right isomerism • Left isomerism
2. Morphological feature of right atrium • Finger like posterior appendage • Smooth surface • Presence of cristae terminalis D) Septum primum lies on RA side