CARDIAC MALPOSITIONS DR ANEESHm
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Transcript CARDIAC MALPOSITIONS DR ANEESHm
Cardiac
Malpositions
PRESENTER : DR ANISH
Cardiac Malpositions
Terminology
Looping of heart
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
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
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 .
Terminology
Displacement : An abnormal cardiac position secondary to
eventration of a hemidiaphragm, agenesis of a lung, or congenital
complete absence of the pericardium
Terminology
Ectopia cordis : Location of the heart outside the thoracic cavity
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
Looping of heart
D-loop: Rightward (“dextro”) bend.
L-loop: Leftward (“levo”) bend
Cardiac looping in late fourth week and early fifth week
Looping
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.
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.
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.
Discordance
Latin “dis” : apart / Inappropriate.
Atrio-ventricular discordance:
Ventriculo-arterial discordance:
A morphologic RA to LV LA to RV.
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.
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.
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
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.
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)
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.
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.
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
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
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
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.
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
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
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
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
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 Pwave 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.
Dome and dart P wave in lead V1/2 :
a left atrial ectopic focus irrespective of atrial situs
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
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.
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
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
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
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
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.
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
Low septal annular attachment
No septal chordal attachments
High septal annular attachment
Triangular orifice (midleaflet)
Elliptical orifice (midleaflet)
Three leaflets
Several papillary muscles
Two leaflets
Two large papillary muscles
Empties into right ventricle
Empties into left ventricle
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)
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
Standard subcostal view
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
liver, hepatic veins, inferior vena cava (IVC), stomach, spleen, and
abdominal aorta are obtained
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
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
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
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
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
Situs Ambiguus
right atrial (asplenia) or left atrial (polysplenia) isomerism
Dextrocardia with situs ambiguus was the most common
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.
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.
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
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
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.
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
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
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
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
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 doubleoutlet right ventricle
Most common complex : dextrocardia, atrial situs ambiguus,
ventricular inversion, and VA concordance with left posterior aorta.
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.
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