Ebook A practical guide to fetal echocardiography normal and abnormal hearts (3E): Part 2

(BQ) Part 2 book “A practical guide to fetal echocardiography normal and abnormal hearts” has contents: Aortic stenosis and bicuspid aortic valve, common arterial trunk, fetal arrhythmias, fetal cardiomyopathies and fetal heart tumors,… and other contents.

Within univentricular atrioventricular connection, three subgroups can beidentified: double inlet, where two atria connect to a single ventricle through twopatent atrioventricular valves; single inlet, where one atrium connects to a singleventricle through a single atrioventricular valve; and common inlet, where bothatria connect to a single ventricle through a single atrioventricular valve (1) Themorphology of the ventricle is generally a left ventricular morphology with arudimentary right chamber On rare occasions, a right ventricular morphologywith a rudimentary left chamber, or a ventricle of indeterminate morphologywithout a rudimentary chamber, can be seen A single ventricle heart, whichresults from a surgical repair of a congenital heart anomaly, should not beclassified as univentricular atrioventricular connection Table 19.1 lists severalcardiac anomalies that may show a single ventricle on fetal echocardiography.

Of those, DIV and TA with ventricular septal defect (VSD) have been commonlyclassified in the univentricular atrioventricular connection and will be discussed

in this chapter Figure 19.1 represents four-chamber views in fetuses with

different cardiac defects and a single ventricle anatomy

Figure 19.1: Spectrum of univentricular atrioventricular connection: fourdifferent fetal heart defects showing a “single ventricle” (V) in the four-chamber

view The detection of one ventricle on fetal echocardiography is not

synonymous with a single ventricle A: Fetus with a hypoplastic left heart with absent left ventricle in mitral and aortic atresia B: Fetus with a hypoplastic right ventricle in pulmonary atresia with intact septum C: Common inlet single ventricle in a fetus with right isomerism and other complex anomalies and (D)

to a common ventricle (Fig 19.2) The most common form of DIV is a doubleinlet to a morphologic left ventricle, representing about 80%, and the anomaly isalso called double inlet left ventricle (DILV) (5) In DILV, a smallunderdeveloped right ventricle (not shown in Fig 19.2) is commonly present andconnects to the single ventricle with a VSD This “remnant” ventricle is a smalloutlet chamber and the septal defect is usually called bulboventricular foramen.The aorta and pulmonary arteries usually arise in D- or L-malposition, anddepending on the looping, one or both vessels (double outlet) may commonlyarise from the small outlet chamber In cases where the bulboventricular foramen

(septal defect) is restrictive, the corresponding arising vessel(s) from the remnantchamber may be diminutive (pulmonary stenosis or aortic coarctation) Otherforms of DIV include a double inlet right ventricle, a DIV of mixed morphology,and a DIV of undetermined or undifferentiated morphology (5) DIV is rare and

is found in 0.1 per 1,000 live births (9) The prevalence is more common in fetalseries due to the easy detection of DIV on the four-chamber view of the heart

Figure 19.2: Schematic drawing of double inlet ventricle Note the presence ofright (RA) and left (LA) atria, two patent atrioventricular valves, and both atriadrain into a single ventricle In most cases, the single ventricle ismorphologically a left ventricle A rudimentary ventricle can occasionally beseen (not shown in this scheme)

Ultrasound Findings

Gray Scale

The four-chamber view is abnormal in DIV as it shows a single ventricle with amissing ventricular septum (Fig 19.3) Identifying the morphology of the singleventricle on ultrasound is based on the anatomic characteristic of themorphologic right and left ventricles as discussed in Chapter 5 The leftventricular myocardium appears smooth with fine trabeculations, whereas theright ventricular myocardium is coarse with an irregular surface Assessment of

atrioventricular valve anatomy and/or insertion of papillary muscles cannot beused to determine ventricular morphology in univentricular atrioventricularconnection Occasionally, the rudimentary right ventricle is seen in the four-chamber plane (Fig 19.4) but in most cases the septal defect (bulboventricularforamen) and the rudimentary right ventricle in DILV are often not visualized inthe four-chamber plane but in a more cranial plane, when an attempt to visualizethe great vessels is made (Fig 19.5) The rudimentary outlet chamber in DILV ismore commonly located on the left side of the main ventricle (L-looping) butcan be located on the right side (D-looping) (2) The great arteries are generally

in L-malposition if the small outlet chamber is on the left side of the ventricle.When the small outlet chamber is localized on the right side, the great arteriesarise either in D-malposition or are normally related with the pulmonary arteryarising from the small outlet chamber (2) Outflow tract obstructions arerecognized due to size discrepancy rather than flow disturbances, which may beabsent A narrow pulmonary artery suggests the presence of pulmonary stenosis

Figure 19.4: Four-chamber view in gray scale in a fetus with a double inletventricle Note that the right (RA) and left (LA) atria drain through two distinctatrioventricular valves into the left ventricle (LV) There is a rudimentary rightventricle (RV) as an outlet chamber drained from the LV L, left.

Color Doppler

Color Doppler may be misleading since two atrioventricular valves are patentand two color stripes are visualized, thus mimicking the virtual presence of aseparation or septum (10) (Figs 19.3 and 19.6) Diagnosis is typically made ongrayscale ultrasound, and color Doppler provides additional information on thepatency of the left and right atrioventricular valves, flow across the VSD, andgreat vessels (Fig 19.5), especially to detect stenosis or atresia (Fig 19.7).Restrictive VSD, which may occur in this condition, is better evaluated usingcolor Doppler

Figure 19.5: Long-axis views in gray scale (A) and color Doppler (B) in the

same fetus shown in Figure 19.4 with a double inlet ventricle (SV) and arudimentary outlet ventricle The rudimentary outlet ventricle is connected with

the SV through a ventricular septal defect (asterisk), called bulboventricular

foramen Aorta (Ao) and pulmonary artery (PA) arise in parallel orientation.Note that the Ao is smaller than the PA, due to the small size of the ventricularseptal defect Aortic coarctation was diagnosed after birth Inf., inferior

Figure 19.6: Fetus at 15 weeks’ gestation with a double inlet ventricle, withboth right (RA) and left (LA) atria draining through two respective

atrioventricular valves into a single ventricle (SV) A is in gray scale and B is in

Early Gestation

DIV can be detected in early gestation (Figs 19.6 and 19.7) by detecting theabsence of a ventricular septum on the four-chamber view as well as abnormallyarising great vessels

Three-Dimensional Ultrasound

The combination of three-dimensional (3D) ultrasound with tomographicimaging permits the simultaneous visualization of the abnormality in the four-chamber plane and the demonstration of the rudimentary ventricle with thecourse of the great vessels Navigating through the volume in an offline settingmay facilitate the evaluation of the spatial orientation of the great arteries.Surface rendering shows the large ventricle with inflow from twoatrioventricular valves and a rudimentary outlet chamber (Fig 19.8) and mayhelp in identifying the spatial relationship of the great vessels

Figure 19.7: Four-chamber (A) and longitudinal (B) views in color Doppler in

a fetus at 15 weeks’ gestation with a double inlet ventricle (same fetus as in Fig

19.6) Note in A that the right (RA) and left (LA) atria drain through two

respective atrioventricular valves into a single ventricle (SV) The longitudinal

is hypoplastic, demonstrates retrograde flow (arrow), and is located posterior to

the aorta (Ao) Inf., inferior; L, left

Figure 19.8: Surface-rendering mode of the four-chamber view in a fetus withdouble inlet ventricle showing the right (RA) and left (LA) atria as well as thesingle ventricle (SV) A small rudimentary ventricle can also be identified

(arrows) L, left; AO, descending aorta.

Associated Cardiac and Extracardiac Findings

Associated malformations in DIV are atresia, hypoplasia or straddling of the

atrioventricular valves, pulmonary (or subpulmonic) outflow obstruction,(sub)aortic outflow obstruction, and conduction abnormalities, primarily due tothe anatomic disruption of the conduction system (1).

The most important extracardiac abnormality to rule out is the presence ofright or left isomerism (see Chapter 30), especially in the presence of a commoninlet ventricle (11) The sequential approach to the ultrasound examination of theheart may permit detection of corresponding abnormalities Chromosomeanomalies and other extracardiac anomalies than isomerism are possible butrather unusual

Differential Diagnosis

Table 19.1 lists several cardiac malformations in the differential diagnosis ofDIV DIV may be missed on prenatal ultrasound in a lateral view of the heart indiastole because the papillary muscles may mimic a ventricular septum in asingle ventricle

Prognosis and Outcome

DIV with patent atrioventricular valves is well tolerated in the fetus Follow-upultrasound is important prenatally as outflow tract obstruction may develop orworsen due to reduced flow and lack of vessel growth The neonatal course ofDIV is dependent on the presence of associated malformations, such asobstruction of the great vessels or atrioventricular valve abnormalities Surgicaltreatment corresponds to a single ventricular repair The type of surgical repair(pulmonary artery banding, Fontan procedure, or other) mainly depends ondetailed evaluation of the great vessel arrangement and perfusion

An overall mortality rate of 29% with follow-up up to 25 years of age wasnoted in an outcome study on 105 patients with DILV and transposed arteries(12) Multivariate analysis showed the presence of arrhythmia and pacemakerrequirement as independent risk factors for mortality, whereas pulmonary atresia

or stenosis and pulmonary artery banding were associated with decreasedmortality (12) Gender, era of birth, aortic arch anomaly, and systemic outflowobstruction were not risk factors for long-term outcome (12) Similar findingswere reported on eight fetuses with DILV with L-transposition of the greatvessels (13) Of these, four fetuses (50%) had pulmonary atresia, one fetus(12.5%) also had TA and coarctation of the aorta (died), and one fetus had

complete heart block and long QT syndrome (died) (13) Overall good outcomewas noted in six (75%) infants (13) The outcome of fetuses with DIV isgenerally good in the absence of associated rhythm abnormalities.

KEY POINTS Double Inlet Ventricle

DIV is the most common form of univentricular atrioventricular

connection

DIV is characterized by two normally developed right and left atria thatconnect via separate right and left atrioventricular valves to a commonventricle

The most common form of DIV is a double inlet to a morphologic leftventricle, representing about 80% of cases

The four-chamber view is abnormal in DIV

In DIV, outflow tract obstruction is often present and affects the vesselarising from the rudimentary ventricle

communication, in the form of a widely patent foramen ovale or atrial septaldefect, is necessary given an obstructed tricuspid valve TA is classified intothree types based on the spatial orientation of the great vessels (14) TA type 1occurs in 70% to 80% of cases and is associated with normally oriented greatarteries (aorta from left ventricle and pulmonary artery from right ventricle) (Fig.19.9) TA type 2 occurs in 12% to 25% of cases and is associated with D-transposition of the great vessels TA type 3, an uncommon malformation, isseen in the remainder of TA cases and usually denotes complex great vesselabnormalities, such as truncus arteriosus or L-transposition TA is rare, with anincidence of 0.08 per 1,000 live births (9) TA is reported in about 4% ofcongenital heart disease prenatally and is more common in prenatal seriesprimarily as it belongs to the group of cardiac anomalies associated with anabnormal four-chamber view (15–18) Figure 19.10 is an anatomic specimen of

Figure 19.9: Schematic drawing of tricuspid atresia with ventricular septaldefect (VSD) Note the absence of the right atrioventricular connection A VSDwith a diminutive right ventricle (RV) is noted Also see the widely patentforamen ovale and the right ventricular outflow tract obstruction (herepulmonary stenosis) LA, left ventricle; RA, right ventricle; LV, left ventricle;

Ao, aorta; PA, pulmonary artery

Figure 19.10: Anatomic specimen of a fetal heart with tricuspid atresia andventricular septal defect (VSD) opened at the four-chamber view plane Theright ventricle (RV) is small and is connected to the left ventricle (LV) by a VSD

with absent right atrioventricular junction The atretic tricuspid valve (yellow arrows) appears as thickened tissue RA, right atrium.

Figure 19.11: Four-chamber view in a fetus at 29 weeks’ gestation withtricuspid atresia and ventricular septal defect The right ventricle (RV) is smalland is connected to the left ventricle (LV) with a ventricular septal defect

(asterisk) Open arrow points to the atretic, thickened tricuspid valve Note the wide foramen ovale (FO) with a redundant flap of the interatrial septum (small arrows) Interatrial and interventricular septa are malaligned LA, left atrium;

RA, right atrium

Figure 19.12: Four-chamber views in gray scale in a fetus at 21 weeks’ (A) and 32 weeks’ (B) gestation with tricuspid atresia and ventricular septal defect

(VSD) Due to the small and restrictive VSD (arrows), the size of the right

ventricle (RV) is diminutive LA, left atrium; LV, left ventricle; RA, right atrium

Color Doppler

Color Doppler confirms the diagnosis on grayscale ultrasound by demonstratingthe lack of blood flow across the tricuspid valve and a patent mitral valve (Fig

19.13) Aliasing is typically noted across the mitral valve on color Doppler due

to increased blood flow (Fig 19.13) The presence of mitral valve regurgitation

on color Doppler prenatally has been associated with poor outcome The rightventricular cavity is filled in late diastole from the left ventricle as left-to-rightshunting through the VSD, and flow across the VSD can be visualized on colorDoppler (Fig 19.13) Color Doppler is also helpful in the evaluation of flowacross the great arteries (Figs 19.14 and 19.15) Flow across the pulmonary

artery is generally antegrade and nonturbulent The suspicion of pulmonarystenosis is generally achieved by a diminutive size of the vessel rather than thedemonstration of turbulent flow on color Doppler, which is typically absent inthese cases Flow across the ductus arteriosus in the three-vessel-trachea view isusually antegrade, but the demonstration of retrograde flow in the arterial duct is

a sign of ductal-dependent pulmonary circulation with possible cyanosis in thenewborn (Figs 19.14 and 19.15) Ductal-dependent circulation in TA is usuallyseen in severe pulmonary stenosis or atresia in association with a small rightventricle Due to limited flow across the foramen ovale and the subsequentlyincreased preload in the right atrium, ductus venosus Doppler will show often a

11 to 13 weeks’ gestation and may represent an early sign of right atrialincreased preload (19).

Three-Dimensional Ultrasound

Tomographic and orthogonal display may demonstrate the main features of TA,such as the abnormal four-chamber view, the size of the small right ventricle, theVSD, and the relationship and size of the great arteries (21, 22) Volumerendering in surface mode (Fig 19.17) or other displays as inversion mode andglass-body mode (Fig 19.18) may help in the evaluation of ventricular size andgreat vessel spatial relationship

Figure 19.13: Color Doppler at the four-chamber view during early (A) and late (B) diastole in a fetus with tricuspid atresia and ventricular septal defect (VSD) (same fetus as in Fig 19.11) In early diastole (A), blood entering the

right atrium (RA) passes across the wide foramen ovale to the left atrium (LA)

(white arrow) and through the mitral valve to the left ventricle (LV) (red arrow).

Color aliasing is seen across the mitral valve due to increased blood flow (A and B) The right ventricle (RV) receives blood from the left ventricle (LV) across

the VSD (blue arrow) primarily in late diastole (B) and systole.

Figure 19.14: The three-vessel-trachea view in color (A and B) and pulsed Doppler (C) in a fetus with tricuspid atresia and restrictive ventricular septal defect with severe pulmonary stenosis (same fetus as in Fig 19.12) A and B show a narrow pulmonary artery (PA) in comparison to the dilated aorta (Ao) A

is during systole and demonstrates antegrade flow across the Ao and PA In B,

reverse flow is demonstrated in the ductus arteriosus (DA) during diastole

Pulsed Doppler interrogation of the DA in C reveals bidirectional flow with

antegrade flow in systole and retrograde flow in diastole, a sign of severeoutflow obstruction and postnatal ductal-dependent pulmonary circulation

Figure 19.15: Tricuspid atresia with ventricular septal defect and pulmonary

atresia A, which is obtained at the three-vessel-trachea view, shows a single enlarged, anterior vessel, aorta (Ao) B is obtained at the three-vessel view and

shows hypoplastic right and left pulmonary arteries (PA) Color and pulsed

Doppler in C reveals retrograde flow (red) in the ductus arteriosus (DA), which

is also confirmed by pulsed Doppler (lower panel) as holosystolic reverse flow.

These findings are typical for pulmonary atresia

Figure 19.16: Transvaginal ultrasound of tricuspid atresia with ventricular

septal defect (VSD) in color Doppler in a fetus at 13 weeks’ gestation A is

obtained at the four-chamber view and shows blood inflow through the mitral

valve into the left ventricle (LV), with blood reaching the right ventricle (RV)

Figure 19.18: Four-chamber view obtained in surface-rendering mode (Left) and glass-body mode (Right) from a 3D color Doppler ultrasound volume of a

fetus with tricuspid atresia and ventricular septal defect (VSD) Note the

difference in size in the cardiac cavities (Left) and the typical direction of flow (Right) from right atrium (RA) across the foramen ovale into the left atrium

(LA) (white arrow), across the mitral valve (red arrow) into the left ventricle (LV) and across the VSD (blue arrow) into the hypoplastic right ventricle (RV).

Asterisk (Left) points to the location of the VSD.

Associated Cardiac and Extracardiac Findings

Associated cardiac findings include a large interatrial communication, such as apatent foramen ovale or an atrial septal defect, transposition of the great vessels,and various degrees of ventricular outflow obstruction Ventricular outflowobstruction varies, from a patent pulmonary artery to stenosis and atresia andfrom patent aortic arch to aortic stenosis, coarctation, or interruption of the aorticarch In a multicenter study on the cardiac anatomy in 60 fetuses with TA, 9fetuses had patent great vessels, 16 had pulmonary stenosis, 11 had pulmonaryatresia, 6 had aortic stenosis, 4 had coarctation of the aorta, 9 had aortichypoplasia, 2 had interrupted aorta, and 3 had a common arterial trunk, orundefined ventriculoarterial connection (23) Interestingly, all fetuses withpulmonary outflow obstruction had ventriculoarterial concordance and almost allfetuses with aortic outflow obstruction had ventriculoarterial discordance (23).Other associated cardiac lesions include persistent left superior vena cava, rightaortic arch, pulmonary venous abnormalities, and juxtaposition of the atrialappendages (23) On some occasions, the great vessels are in a correctedtransposition orientation, which was found in 6 of 60 cases in the seriesdescribed previously (23) Due to the atrioventricular discordance, the rightventricle is on the left side and the atretic valve is found on the left side, whichmay erroneously suggest mitral atresia with VSD In a study on the prenatalcourse and outcome of TA in 54 fetuses, 28 had a concordant ventriculoarterialconnection of which 14 also had pulmonary outflow obstruction, and 25 had adiscordant ventriculoarterial connection of which 14 also had aortic outflowobstruction (24) The peak velocity index for veins in the ductus venosus wassignificantly elevated in 19 fetuses assessed and this finding did not correlatewith adverse intrauterine outcome (24) There were associated extracardiacanomalies in 12 fetuses, with five chromosomal anomalies (24) Seventeen of

the 54 cases underwent termination of pregnancy, two died in utero, two died ininfancy, and 33 children survived with a median follow-up of 26 (range, 12–120)months, resulting in a short-term overall survival in continued pregnanciesexceeded 89%, with the greatest rate of loss being in the first year of postnatallife (24).

Extracardiac anomalies can be found in TA, and fetal karyotyping should beoffered despite a rare association with chromosomal aberration, including 22q11microdeletion (23)

Differential Diagnosis

Two cardiac malformations are commonly involved in the differential diagnosis

of TA: pulmonary atresia with intact septum and DIV DIV was previouslydiscussed in this chapter Table 19.2 differentiates TA with VSD frompulmonary atresia with intact septum, both presenting with hypoplastic rightventricle in the four-chamber view

TABLE

19.2

Differentiating Features of Tricuspid Atresia with Ventricular Septal Defect (TA-VSD) and Pulmonary Atresia with Intact Ventricular Septum (PA-IVS)

Intact septum bulging to the left ventricle

Interatrial

septum

Large interatrial communication with

Normal foramen ovale

redundant foramen ovale

Tricuspid valve Thickened echogenic

tissue and no valve apparatus

Generally dysplastic tricuspid valve with limited valve excursion

occasionally with tricuspid regurgitation

Right atrium Normal size with a

large interatrial communication

May be dilated due to severe tricuspid regurgitation

Pulmonary

artery and

valve

Patent valve (rarely atretic), narrow pulmonary artery

Atretic valve, narrow pulmonary artery

Ductus

arteriosus

Generally antegrade flow

communications

Ventriculocoronary arterial communications may be present

in a multicenter series of TA diagnosed prenatally (23)

Postnatal outcome is dependent on associated cardiac and extracardiac

findings An outcome study of prenatally diagnosed TA estimated an 83%survival at 1 year of age following active management (23) By multivariateanalysis, two independent factors were associated with an increase in time-related mortality in the actively managed group: presence of chromosomalanomaly or syndrome and use of extracorporeal membrane oxygenation (23).This study showed that compared with published observations of TA diagnosedpostnatally, antenatal diagnosis of TA appears to have similar short-term survival

in pregnancies surviving to birth (23)

Surgical correction of TA revolves around bypassing the right ventricle andcreating a conduit between the systemic venous blood and the pulmonarycirculation Most TA patients are treated with the Fontan procedure, whichprimarily consists of a cavopulmonary shunt If the pulmonary artery is ofnormal size, preventing pulmonary overcirculation and pulmonary hypertension

is achieved by banding the pulmonary artery The overall mortality rate inpatients who were treated with the Fontan procedure was between 7% and 10%

Prenatal follow-up of TA fetuses with serial ultrasound examination isimportant to assess the patency of the foramen ovale and the presence

of right ventricular outflow obstruction

4 Penny DJ, Anderson RH Other forms of functionally univentricular hearts

In: Anderson RH, Baker EJ, Redington A, et al, eds Pediatric Cardiology.

3rd ed Philadelphia, PA: Elsevier Health Care-Churchill-Livingstone;2010:665–686

8 Anderson RH, Tynan M, Freedom RM, et al Ventricular morphology in the

univentricular heart Herz 1979;4:184–197.

9 Hoffman JI, Kaplan S The incidence of congenital heart disease J Am Coll Cardiol 2002;39:1890–1900.

10 Chaoui R, McEwing R Three cross-sectional planes for fetal color Doppler

echocardiography Ultrasound Obstet Gynecol 2003;21:81–93.

11 Van Praagh R, Ongley PA, Swan HJ Anatomic types of single or commonventricle in man: morphologic and geometric aspects of sixty necropsied

cases Am J Cardiol 1964;13:367–386.

21 Chaoui R, Hoffmann J, Heling KS Three-dimensional (3D) and 4D colorDoppler fetal echocardiography using spatio-temporal image correlation

hundred consecutive patients: factors influencing early and late outcome J Thorac Cardiovasc Surg 1997;114:376–391.

26 Sharma R, Iyer KS, Airan B, et al Univentricular repair Early and midterm

results J Thorac Cardiovasc Surg 1995;110:1692–1700; discussion 1700–

1691

Definition, Spectrum of Disease, and Incidence

As explained in Chapters 5 and 7, the tricuspid valve inserts in the normal heartslightly more apically on the interventricular septum than the mitral valve.Ebstein anomaly belongs to the few abnormalities affecting the valveattachment In this disease, the septal and posterior leaflets of the tricuspid valveare displaced inferiorly from the tricuspid valve annulus, toward the apex of theheart, and originate from the right ventricular myocardium (Figs 20.1 and 20.2).The anterior tricuspid leaflet maintains its normal attachment to the tricuspidvalve annulus The proximal portion of the right ventricle is then continuouswith the true right atrium and forms an “atrialized” portion of the right ventricle(Figs 20.1 and 20.2) The spectrum of Ebstein anomaly is wide and varies from

a minor form, with minimal displacement of the tricuspid valves with mildtricuspid regurgitation, to a severe form, with the “atrialization” of the entireright ventricle (Figs 20.3 and 20.4)

Associated anomalies are not uncommon and include right ventricularoutflow tract obstruction, either as pulmonary stenosis (Fig 20.5) or atresia, andatrial and ventricular septal defects The pathogenesis of pulmonary stenosis oratresia in association with Ebstein anomaly may be related to a reduction in flowacross the pulmonary valve due to severe tricuspid regurgitation Atrial septaldefect may also result from the dilation of the right atrium due to the severeregurgitation noted in utero Ebstein anomaly is one of the less common cardiacabnormalities occurring in about 0.5% to 1% of congenital heart disease in live

births (1), with an equal male-to-female distribution (2) Ebstein anomaly ismore common in prenatal series as it accounts for 3% to 7% of congenital heartdisease in fetuses (3, 4) This higher prenatal rate is related to an increase in fetal

or early neonatal death in severe cases due to severe tricuspid regurgitation andassociated pulmonary hypoplasia

Figure 20.1: Schematic drawing of Ebstein anomaly See text for details LA,left atrium; RA, right atrium; LV, left ventricle; RV, right ventricle

Figure 20.2: Apical four-chamber view in a fetus with Ebstein anomaly

demonstrating the typical apical displacement of the tricuspid valve (TV) (open straight arrows) compared to the mitral valve (MV) The right atrium (RA) is

dilated due to severe TV regurgitation, and the interatrial communication

through the foramen ovale (FO) is wide (open curved arrow) due to increased

right-to-left shunting of blood LA, left atrium; LV, left ventricle; RV, rightventricle

chest Lungs (L) are compressed and small Compare with lungs in Figure 20.3.

The fetus also had hydrops at presentation at 22 weeks, here recognizable as

pericardial effusion (asterisk in A) LA, left atrium; RA, right atrium; LV, left

of Ebstein anomaly have such a pronounced cardiomegaly that the heart fillsmore than two-thirds of the thoracic cavity and both lungs are compressedresulting in lung hypoplasia (compare Figs 20.3 and 20.4) Some cases can alsoresult in cardiac failure and hydrops, which can be an additional reason, besidesthe cardiomegaly, for pregnancy referral

Color Doppler

In severe cases of Ebstein anomaly with an enlarged heart, color Doppler helps

in the confirmation of severe tricuspid regurgitation (Fig 20.6) In early stages,however, before the right atrium or the whole heart is enlarged, color Dopplercan visualize the typical severe regurgitation and leads to the diagnosis (Fig

with peak velocities of greater than 200 cm/s (Fig 20.8) The systolic regurgitantjet of the tricuspid valve typically arises from the middle of the right ventricle inEbstein anomaly, in contrast to the regurgitant jet of tricuspid dysplasia or otherfunctional tricuspid regurgitations, which arise at the level of the tricuspid valveannulus, an important differentiating point (Fig 20.6) Color Doppler of the rightoutflow tract shows either reverse flow in the ductus arteriosus toward thepulmonary valve or antegrade flow into the typically narrow pulmonary trunkwhen pulmonary atresia or stenosis is present (6)

Figure 20.5: Transverse view of the ductal arch (DA) in a fetus with Ebsteinanomaly showing right ventricular outflow tract obstruction Note the narrowpulmonary artery (PA) compared to the size of the ascending aorta (AO) SVC,

Figure 20.6: Color Doppler during systole at the four-chamber view in two

fetuses (A and B) with Ebstein anomaly, demonstrating severe tricuspid

regurgitation into the dilated right atrium (RA) Open arrows point to the site of closure of the dysplastic tricuspid valves Solid arrows point to the attachment of

the mitral valves Note the anatomic origin of the regurgitant jet, deep in theright ventricle (RV), a differentiating feature from tricuspid dysplasia (see textfor details) LA, left atrium; LV, left ventricle; L, left

Figure 20.7: Apical four-chamber views in gray scale (A), color Doppler in diastole (B), and color Doppler in systole (C) in a fetus with mild Ebstein anomaly at 22 weeks’ gestation Note the absence of marked cardiomegaly in A.

In diastole (B), color Doppler shows normal atrioventricular filling In systole (C), severe tricuspid regurgitation is noted with the regurgitant jet starting near

the apex of the heart Open arrows point to the site of closure of the dysplastictricuspid valves Solid arrow points to the attachment of the mitral valve LA,left atrium; RA, right atrium; LV, left ventricle; RV, right ventricle

Figure 20.8: Tricuspid regurgitation shown on color and pulsed Doppler in afetus with Ebstein anomaly Note the holosystolic duration of the regurgitant jet

(arrows) with peak velocities exceeding 270 cm/s RA, right atrium; RV, right

ventricle

Early Gestation

The presence of tricuspid regurgitation can be present at 11 to 14 weeks’gestation in fetuses with Ebstein anomaly, but the main findings of cardiomegalyand dilated right atrium are typically seen later in gestation Early severe caseswith cardiomegaly may be associated with a thickened nuchal translucency and

fetal hydrops (Fig 20.9), a sign of impending fetal demise Given that themajority of severe cases of Ebstein are suspected in early gestation, mild Ebsteincases can be missed in utero and are detected in infancy or even later intoadulthood (7).

Three-Dimensional Ultrasound

The display of Ebstein anomaly with three-dimensional (3D) ultrasound, such astomographic imaging or orthogonal planes, can demonstrate in one view thecardiomegaly, the level of attachment of the tricuspid valve leaflets, and thediminutive pulmonary artery Surface rendering (Fig 20.10) can provide a betterassessment of the abnormal valve anatomy (8) and could, in the future, be ofimportance in counseling parents for the options of postnatal therapy Tricuspidregurgitant jets can be displayed in surface rendering and glass-body mode (Fig

Figure 20.9: Gray scale (A), color (B), and pulsed Doppler (C) in a fetus at

12.5 weeks’ gestation with Ebstein anomaly Note the presence of generalized

hydrops (asterisks) in A and B The displaced apical attachment of the tricuspid valve in the right ventricle (RV) is shown in A (arrow) Severe tricuspid regurgitation originating near the apex of the RV is shown in B (arrow).

Holosystolic tricuspid regurgitation with peak velocities of 120 cm/s is

demonstrated in C RA, right atrium; LV, left ventricle; L, left.

Figure 20.10: 3D ultrasound in surface mode display of the four-chamberview in a fetus with Ebstein anomaly The large right atrium (RA) and the wide

foramen ovale (FO) are demonstrated (open curved arrow) Different levels of attachment of the tricuspid (TV) (open straight arrows) and mitral valves (MV)

On occasion, it may be difficult to differentiate prenatally between Ebsteinanomaly and tricuspid valve dysplasia The origin of the tricuspid regurgitant jetmay help in differentiating these two lesions In tricuspid valve dysplasia, the jetarises from the normally inserted tricuspid valve at the level of the annulus,whereas in Ebstein anomaly, the origin of the regurgitant jet is displacedinferiorly within the right ventricle owing to the low insertion of the septal andposterior tricuspid valve leaflets (Figs 20.6 and 20.7) Severe tricuspidregurgitation with cardiomegaly can be found in dilative cardiomyopathy and inother noncardiac lesions with fetal hemodynamic impairment Premature closure

of the ductus arteriosus may also be present with tricuspid regurgitation Colorand pulsed Doppler velocities across the ductus arteriosus help in differentiatingthis entity from Ebstein anomaly

Prognosis and Outcome

Several prenatal series of Ebstein anomaly reported poor prognosis, with about45% of fetuses dying in utero and an overall 80% to 90% mortality (14, 15).Poor prognostic markers prenatally include massive cardiomegaly, decreasedright ventricular outflow due to pulmonary stenosis, and fetal hydrops (14, 16)(Fig 20.9) Compression of the lungs may contribute to pulmonary hypoplasia, asignificant risk factor for the neonate Prenatal diagnosis of Ebstein anomaly isassociated with a poor outcome given an inherent selection of the most severecases The authors observed that when cardiomegaly is detected in earlygestation, especially before 20 weeks, the prognosis is worsened

An echocardiographic grading score for neonates with Ebstein anomaly wasproposed that involves calculating the ratio of the combined area of the rightatrium and atrialized right ventricle to that of the functional right ventricle andleft heart in a four-chamber view at end diastole (17) (Fig 20.12) Four grades ofincreasing severity were described and are shown in Table 20.1 withcorresponding outcome (17) Left heart abnormalities involving the myocardium

or valves were observed in 39% of primarily adult patients with Ebstein anomaly

in one study, suggesting that Ebstein anomaly should not be regarded as adisease confined to the right side of the heart (18) In a review of 37 fetuses with

Ebstein anomaly (n = 26) and tricuspid valve dysplasia (n = 11), anterograde

flow through the pulmonary valve on the first fetal echocardiography was

associated with a good outcome and a retrograde flow was strongly associatedwith fetal or neonatal death (19) Another study on the perinatal course ofEbstein anomaly and tricuspid valve dysplasia in 21 fetuses (17 with Ebstein and

4 with tricuspid valve dysplasia) revealed a shorter combined isovolemiccontraction and relaxation time for nonsurvivors compared with survivors whensubanalysis of the left ventricular myocardial performance index was performed(20)

Figure 20.12: Calculation of the prognostic score for outcome of fetuses with

Ebstein anomaly An apical four-chamber view is shown in A and enlarged and colored in B The area of the right atrium (RA) with the atrialized ventricle is

measured (blue in B) and divided by the sum of the area of the remaining right ventricle (RV), the left atrium (LA) and the left ventricle (LV) (green in B) A

score below 0.5 predicts a favorable outcome whereas a score greater than 1.5signalizes very poor outcome See Table 20.1 for details

TABLE

20.1

Echocardiographic Prognostic Score for Fetuses and Infants with Ebstein Anomaly