- Echocardiography for congenital heart disease (CHD) is difficult because it studied the detail anatomy of heart along with function of each component.
- A successful Echocardiography of children requires not only a thorough knowledge of spatial cardiac anatomy but also the understanding of how best to approach the congenital cardiac defects.
- The Echocardiographic approach to the diagnosis of complex congenital heart disease involves a segmental analysis of heart.
- In this type of analysis, the heart can be thought of as being much like a segment or house.
Sequential segmental analysis: Cardiac House
- In the cardiac house each atrium is on the ground floor, the ventricles on the second floor, and the position of each great vessel is at the top of the house.
- in addition, each house needs staircase to connect the floors
- In a cardiac house, atrioventricular and ventriculoarterial connection are the staircase which should be in right position.
Cardiac segments are :
- Each region, in turn, is partitioned into two components, usually right sided and left sided.
- Possibility of a connection between these three regions is limited.
Basic Identification steps :
1. Atrial situs
- Atria are the most important structure to identify and if not correctly identified, the entire house comes tumbling down.
- Situs refers to the topology or spatial position of the structure. In atrial situs solitus, the morphologic right atrium is on the right, and the morphologic left atrium is on the left.
- In situs ambiguous, the atria are not differentiated as right and left atria.
2. Ventricular loops
- The next step in the diagnosis of complex congenital heart disease is determination of the bulboventricular loop.
- In general, the convexity of the aorta points to the position of the right ventricle and, thus helps indicate bulboventricular loop.
- Ventricular inlets or atrioventricular valves are the marker of ventricle.
- Tricuspid valve to the right indicates d-loop, tricuspid valve to the left indicates l-loop.
Chirality or handedness a concept proposed in 1980 by Van Praagh and colleagues. The morphologic right ventricle in d-loop is right handed. The thumb fits in tricuspid valve, palm on the ventricular septum, fingers in the infundibulum, back of the hand on free wall of right ventricle.
- Situs solitus – d loop: MRV is right handed
(Thumb – TV, palm – IVS, fingers – infundibulum, wrist – apex, back of hand – free wall of RV)
- Situs inversus – l loop: MRV is left handed
- Both are mirror images!!
4. Apical rotation
- The final spatial position determine by the degree of apical rotation.
- Cardiac apex pivots to the hemithroax opposite to the bulboventricular loop.
- Thus, in a normal d-loop, the apex pivots to the left hemithorax, and in a normal l-loop (that is, one in the setting of situs inversus), the apex pivots to the right hemithorax.
- Failure of complete apical pivoting is commonly associated with discordant atrioventricular connections.
Abnormalities of apical rotation
- Superior- inferior ventricles: abnormal tilting of the apex in the frontal plane.
- Criss- cross ventricles: abnormal apical rotation along the longitudinal axis.
- Dextroversion: Lack of apical pivoting in situs solitus d-loop resulting in abnormal positioning of the apex.
5. Great Artery connection
- Aortic valve is situated posterior and to the right of the pulmonic valve.
- Transposition is present when the aortic valve and ascending aorta are anterior to the pulmonary valve and main pulmonary artery.
- The more current definition of transposition proposed by Van Praagh and collegues is based on the ventriculoarterial connections and not the spatial interrelationships.
Steps (Features) of sequential segmental analysis
Step 1—Thoraco-abdominal Visceral sidedness/ situs
- Situs solitus:
- Situs inversus
- Situs ambiguous
Step 2 – Cardiac position
1) Levocardia 2) Dextrocardia 3) Mesocardia
Step 3— Atrium
Systemic & Pulmonary venous return can be helpful in identifying the atria.
Sytemic & Pulmonary venous drainage
Abnormalities in systemic venous return
Systemic venous drainage
- Interrupted IVC
- Azygos stenosis
- Superior vena caval (SVC) stenosis
- Bilateral SVC or persistance left SVC
Abnormalities in pulmonary venous return
Pulmonary venous drainage
- Pulmonary vein stenosis
Step 3—Atrial anatomy
Step 3—Atrial septal morphology
Step 3—Applied anatomy of atrium
- Common atrium
- Hypoplastic atrium
- Atrial dilatation
- Atrial isomerism
- Atrial aneurysm
- Juxta position of atrial appendage
- Tumor/ clot/ thrombus in atrium
Step 3—Atrial isomerism
Step 3— Atrium
Abnormalities of Atrial septum
- Ostium Secundum Atrial Septal Defect
- Ostium Primum Atrial Septal Defect
- Patent foramen ovale
- Sinus Venosus Atrial Septal Defect
- Common or single atrium
- Mixed Atrial Septal Defect
Step 3—Ostium secundum ASD
Step 3—Ostium Primum ASD
Step 3—Sinus venosus ASD
Step 3—Common atrium
Juxtaposition of Atrial appendage
- Left juxtaposition more common
- Causes unusual transverse orientation of IAS
- Associated with complex CHDs: TGA, TA
Step 4 — Atrio-ventricular connection
- Concordant connection
- Discordant connection
- Valvular Atresia/stenosis/regurgitation
- Double inlet
- Common AV connection
- Straddling of valves
- Criss-cross ventricle
- Superior inferior ventricle
Step 4—Concordant or discordant atrioventricular connection
- Concordant atrioventricular connection:
Situs solitus with D-loop or situs inversus with L-loop.
- Discordant atrioventricular connection:
Situs solitus with L-loop or situs inversus with D-loop.
Step 4—AV valve Anatomy
Step 4—Tricuspid valve —Applied anatomy
- Tricuspid Atresia
- Tricuspid stenosis
- Tricuspid regurgitation
- Hypoplastic valve
- Ebstein’s anomaly
Step 4—Mitral Valve — Applied anatomy
- Mitral valve prolapse
- Cleft of mitral valve
- Double orifice mitral valve
- Parachute mitral valve
- Congenital mitral stenosis
- Ruptured mitral valve chordae
- Submitral aneurysm
DILV with TGA
Step 5 — ventricles
- According to Anderson & Colleagues a chamber is ventricle if it receives 50% or more of an inlet (rule of 50)
- A chamber need not to be have an outlet to be a ventricle.
- eg. Left ventricle in DORV is a ventricle because it receives the mitral valve even though it does not have an outlet.
- Rudimentary: a chamber that receives less than 50% of an inlet and therefore do not quantify to be a ventricle.
Step 5—Anatomy of ventricles
Step 5—ventricular position
Step 5—Applied anatomy of ventricles
Superior inferior ventricle
Step 5 –Ventricular hypoplasia
- Hypoplastic Rt heart syndrome
- Hypoplastic left heart syndrome
Step 5—Applied anatomy of ventricular septum
- Hypertrophoid septum
- Vetricular septal defect
Outlet VSD/Doubly committed/Sub pulmonic
3. Absent septation
Step 5—Defect in Septation, VSD
- Conus is the cavitary soace formed by muscular segment of the heart that connects ventricle with great arteries.
Sub – Pulmonic
Step 7—Ventriculo-arterial connection
Applied anatomy Pulmonary & Aortic Valve
Step 7—DORV, VSD, PS
Suspected vegetation in Melody valve
Suspected vegetation in Melody valve
Step 8 — Great vessels
Step 8—D-TGA, Large VSD
step 8—Abnormalities of great vessels
Step 8—Abnormalities of Arch of aorta
Anomalous origin of neck vessels
- Hypoplastic aortic arch
- Double aortic arch
- Interrupted aortic arch
Abnormalities of descending aorta
Abnormalities of coronary artery
- 2.Cameral fistula
- 3.Aneurysmal dilatation of coronary artery
- 4.Thrombus formation
- 5.Coronary stenosis
- Single origin of coronary artery
Aneurysmal dilatation of coronary artery
Abnormalities of chamber
- Cardiac embolism
How to write Paediatric Echo report
- Description of Cardiac lesion
- Measurement of cardiac chambers & vessels
- Evaluation of valves & gradients
- Evaluation of cardiac functions
- Wall motion abnormalities
- Conclusion & recommendation
In the segmental approach the focus is upon the structural components or segments of the heart and the connections between them which allows the accurate anatomical and physiological diagnosis, conceptualizing heart dynamics and analyzing the defects including complex congenital heart defects. This is essential for proper management and selection of therapeutic options like medical management, catheter interventions or the surgical correction.