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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5774_Библиотеки_им_академика_М_И_Перельмана.pdf
214
Q. Zhu et al.
Because of the simultaneous imaging of blood
ow and tissue, the ow in the blood vessel and
the anatomic relationship with vessels are displayed intuitively and clearly while performing
2-D scanning. The advantages include higher frequency and spatial resolution, high sensitivity to
blood ow signals, and angle-independent, which
contribute to an ideal display of fetal pulmonary
vessels. In recent years, many scholars have combined B-ow technology with STIC to achieve a
3-D visualization of small vessels in the fetal pulmonary circulation, improving the hemodynamic
interpretation and diagnosis of CHD with abnormal pulmonary circulation.
– STIC in cardiac function assessment
An accurate and reliable cardiac output measurement method is of great signicance for evaluating the abnormalities of fetal cardiac structure
and function. In the measurement of fetal heart
function by 2-D echocardiography, it is relatively
reliable to measure the time velocity integral
(TVI) by detecting the Doppler spectrum of blood
ow in the outow tract. Measure the inner diameter (D) of the aorta and pulmonary artery, and
calculate the stroke volume of LV and RV respectively, using the formula SV = π × (D/2)
2
×TVI.The angle between the sampling line and
the blood ow is required less than 20 °, which
needs a very suitable fetal position and is very
time-consuming. It is a pity that this application
has limited clinical value. Recently, researchers
collect fetal heart volume data by STIC and have
used various powerful post-processing technologies to objectively calculate the fetal cardiac volume and evaluate cardiac function.
– Clinical application of RT-3DE
Real-time three-dimensional echocardiography
(RT-3DE) can collect images in real time and
simultaneously display 3-D dynamic cardiac
images. RT-3DE contains four display modes:
real-time 3-D, color 3-D, full-volume 3-D, and
three-plane 3-D. At present, RT-3DE has been
widely used in the diagnosis of heart structure and
valve disease, measurement of ventricular volume,
and cardiac function. At the same time, RT-3DE
has developed a new way for the diagnosis of fetal
CHD.RT-3DE, as a supplement to 2-D echocardiography, enables prenatal diagnosis of congenital structural and functional abnormalities of the
fetus. The volume data obtained by RT-3DE is less
affected by fetal movement and fetal respiration in
the process of image collection, which reduces the
distortion and pseudo-image caused by fetal
movement. The clinical application of RT-3DE
mainly includes the following aspects: (1) Observe
the fetal cardiac anatomical structure, especially
some views that are difcult to be displayed by
2-D echocardiography. (2) Display the plane view
of the heart and great arteries and complex cardiac
malformations visually, such as ASD and VSD,
DORV, tricuspid atresia, transposition of the great
arteries, permanent arterial trunk, etc. (3) Measure
the fetal cardiac volume and evaluate the fetal
heart function in a relatively accurate way.
9. Clinical application of 4-D fetal echocardiography
In recent years, many researchers are devoted to the
development of new technologies to improve the prenatal diagnosis rate of CHD.The latest technology applied
to fetal cardiac examination is real-time and single cardiac cycle 4D imaging (4D), which can acquire the full
volume cardiac images within a cardiac cycle. 4-D echocardiography can visually display the spatial structure of
the fetal heart in real time, realizing veritable real-time
full-volume cardiac imaging. Compared with traditional
full-volume cardiac imaging, 4-D echocardiography can
reach 90× 90 °, with exible size according to frame
frequency and resolution, no longer requires image
splicing, electrocardiogram trigger, or breath-holding.
4-D echocardiography starts a new era of fourdimensional cardiac imaging. With the progress of computer technology, these new technologies, which will
play a more prominent role in prenatal screening of fetal
CHD and eugenics, will inevitably become a necessary
complement to 2-D echocardiography.
10. New application of fetal cardiac function evaluation
A reliable noninvasive assessment of fetal cardiac
function is affected by many factors, including small fetal
heart volume, unclear display of ventricular intima, difculty in standardizing fetal cardiovascular structure, orientation, fetal movement, a poor acoustic window of
maternal abdominal wall, and irregular geometry of fetal
RV.The RV may have geometric changes if there is a fetal
arrhythmia accompanied by abnormal heart function. It is
challenging to evaluate fetal ventricular function accurately by the conventional evaluating method of adult and
child. Abnormal myocardial systolic and diastolic functions coexist in fetal cardiac insufciency cases, so it is
more reasonable to perform a detailed cardiac functional
assessment comprehensively.
Tei index is not affected by ventricular geometry
shape, heart rate, and gestational age in the fetus. The
measurement of the Tei index is reproducible and
straightforward, which is a practical method to evaluate
fetal cardiac function. Tei index can evaluate fetal car-
4 Ultrasonic Diagnosis ofFetal Heart
215
diac function reliably, under physiological or pathological conditions. In the case of cardiac insufciency, Tei
index of fetal ventricular cavity increases. Some
researches show that the Tei index can evaluate the cardiac function of edema fetus. Tei index measurement is
limited by the small volume of the fetal heart in early
pregnancy. Moreover, the Tei index detection in the fetal
ventricle is difcult, limiting the application of the Tei
index in fetal arrhythmia.
Huhta and colleagues developed the cardiovascular
prole score (CVPS, Table 4.1), a multivariate scoring
system to evaluate cardiovascular function. CVPS helps
to predict the outcome of hydrops and guide its treatment. Furthermore, CVPS can be used to evaluate the
prenatal intervention of severe congenital cardiovascular
malformation. It is also commonly applied to choose the
right opportunity for intrauterine treatment and evaluate
the efcacy of fetal arrhythmia/heart failure. It is generally considered that intervention should be performed
once the CVPS system score decreases. The treatment,
according to etiology, can achieve ideal results when the
score of CVPS is more than 7 points. If 7 points>CVPS
≥5 points, whether to take treatment measures or not
remains controversial. Most of these cases observe the
dynamic changes after individual treatment. The perinatal mortality is high, and the treatment is of little signicance when the CVPS is less than 5 points. Clinical
intervention may inhibit the adaptive protection of the
mother and fetus, exposing the mother–fetus complex to
a state of high stress, and result in unnecessary complications that threatening the safety of the mother and
fetus. CVPS is negatively correlated with the Tei index.
Therefore, the combination of CVPS and Tei index in
the evaluation of the diagnosis, treatment, and prognosis
of fetal cardiac failure will be more instructive in
clinical.
4.3 Echocardiography ofFetal
Arrhythmia
Fetal cardiac arrhythmia is dened as irregular fetal cardiac
rhythm or abnormal fetal heart rate that beyond the normal
range when there is no uterine contraction during a routine
prenatal examination. Fetal arrhythmias are detected in
1%~ 2% of all pregnancies. Normal fetal heart rate (FHR)
ranges between 120 and 160 beats per minute (bpm), with a
regular rhythm. When the FHR is less than 80% of the low
normal FHR, there is a sign of fetal bradycardia. And fetal
tachycardia is suggested if the FHR is more than 120% of the
high normal FHR. Premature contraction is the premature
beats of the atria or ventricles. The difference between supraventricular tachycardia and ventricular tachycardia is that the
former originates from atrial premature beats and the latter
from ventricular premature beats. There is an entirely contractive dissociation of the atria and ventricle in complete
heart block cases. The rst-degree heart block refers to a prolonged PR interval caused by the delayed atrioventricular
conduction. The second-degree atrioventricular block refers
to cyclical ventricular block because of intermittent
conduction abnormalities, consisting of Mobitz type I and
Mobitz type II.Mobitz type I is characterized by the gradually prolonged PR interval and gradually shortening RR
interval, following by a heart block. Mobitz type II refers to
the cyclical atrioventricular block without progressive prolonged PR interval. Irregular heart rhythm refers to the heart
rate ranges within normal limits, while its fastest heart rate is
25–30 more beats per minute than the slowest—serious
arrhythmia resulting in fetal heart failure and demise. In the
fetus, auscultation can reect no more than whether the heart
rate is regular, failing to dene the rhythm characters. It is
challenging to acquire fetal ECG by other noninvasive methods. Fortunately, fetal echocardiography can observe the
fetal cardiac structure and function in real time, and deter-
Table 4.1 Cardiovascular prole score (CVPS)
Project 2 points 1 point 0 points
Hydrops None Ascites, pleural effusion, or pericardial effusion Edema of skin
Heart area/ chest area
Cardiac function Normal MV and TV biphasic
Arterial Doppler of
umbilical artery
Venous Doppler of
umbilical vein and ductus
venosus
> 0.20 and≤0.35
diastolic lling
0.35~0.50 >0.50 or <0.20
Holosystolic tricuspid regurgitation Holosystolic mitral
regurgitation
Monophasic lling
216
ab
Q. Zhu et al.
mine the type of fetal arrhythmia, becoming the most valuable method to diagnose fetal arrhythmia.
The diagnosis, classication, and treatment of fetal
arrhythmia by fetal echocardiography are based on the electrophysiology and timing analysis of the atria and ventricle.
Currently, M-type, spectral Doppler and tissue Doppler
imaging (TDI) are used to describe the movement at the
atrioventricular level, separately. Although fetal echocardiography is difcult to diagnose complex arrhythmias, it is
competent to indicate the prognosis and guide the treatment
for its validity and relative accuracy.
1. Echocardiographic assessment of the fetal arrhythmia
• M-mode echocardiography
M-mode ultrasound is the most classical and com-
monly used method to evaluate arrhythmia. By 2-D
ultrasound, place the M-mode sampling line across the
atrial wall and the ventricular wall to obtain a clear
M-mode image. The motion curve of the atrial wall
represents atrial systole and diastole, and so does the
curve of the atrioventricular valve. The moving curve
of the ventricular wall represents ventricular systole
and diastole, and so does the curve of the semilunar
valve. These motion curves are representations of
ECG conduction, intuitively showing the sequence
and rhythmic relationship of the atrial and ventricular
conduction. Determine the types of fetal arrhythmia
by analyzing the corresponding relationship among
the motion curves above (Fig.4.34).
• Spectral Doppler echocardiography and tissue Doppler
echocardiography
Position the spectral Doppler ultrasound sample
volume at different sites of the heart, containing left
ventricular inow - outow tract area, the adjacent
area of SVC and ascending aorta, the adjoining area of
IVC and abdominal aorta, and area of pulmonary
artery and vein. Atrial rate, ventricular rate, and time
interval are calculated according to the blood ow
spectrum. Determine the types of arrhythmias depending on the corresponding relationship between the
atrial rate and the ventricular rate. The spectral imaging of the inow and the outow tract can be obtained
when placing the sampling volume at the intersection
of the ventricular inow and the outow tract. The
starting point of the inow tract spectral A wave represents the beginning of atrial systole, and that of the
outow tract spectrum represents that ventricular diastole starts. According to the above description, we can
dene specic fetal arrhythmia by analyzing and the
corresponding relationship between the systolic and
diastolic motion of the atrium and ventricle. Tissue
Doppler imaging, reecting the atrioventricular movement, is acquired when placing tissue Doppler sampling volume in the lateral septum of mitral/tricuspid
annular and left/right ventricular wall (Fig.4.35).
2. Classication of fetal arrhythmia
Fetal cardiac arrhythmia is dened as irregular fetal
cardiac rhythm or abnormal fetal heart rate that outside
the normal range when there is no uterine contraction
during a routine prenatal examination. When the FHR is
less than 80% of the low normal FHR, there is a sign of
fetal bradycardia. And fetal tachycardia is suggested if
the FHR is more than 120% of the high normal FHR.
Fetal arrhythmia is generally divided into irregular
arrhythmia, tachyarrhythmia, and bradyarrhythmia.
Tachyarrhythmia is dened as FHR higher than 200bpm,
Fig. 4.34 Atrioventricular motion curves of the normal fetal heart. (a)
The upper curve represents the atrial wall, and the lower one represents
the ventricular wall. The lines in the middle are the motion curves of the
ventricular septum and the atrioventricular valve. There is a one-to-one
correspondence between the motion curve of the atrial wall and the
ventricular wall. (b) Two sampling lines pass through the atrial wall and
the ventricular wall, respectively, and the motion curves of them show a
one-to-one correspondence either
4 Ultrasonic Diagnosis ofFetal Heart
217
a
b
c
Fig. 4.35 Pulsed Doppler and tissue Doppler echocardiography
images. (a) It shows A wave, the atrial excitation wave, when the PW
samples are placed at the adjacent areas of the inow and outow tracts
of the left ventricle. (b) PW is sampled at PA and PV, showing normal
consisting of sinus tachycardia, supraventricular tachycardia, atrial utter, and atrial brillation. Bradyarrhythmia
is characterized by FHR less than 100 bpm, including
sinus bradycardia, non-conductive premature beat, and
complete heart block. The irregular types include premature atrial contraction, premature ventricular contraction,
and tachyarrhythmia with heart block.
3. Echocardiographic characteristics of fetal arrhythmia
• Irregular arrhythmia
Irregular rhythm refers to that the heart rate ranges
within normal limits, while its fastest heart rate is
25–30 more beats per minute than the slowest.
According to the frequency of occurrence, the atrial
and ventricular premature contractions that happened
in the fetus can be divided into incidental (<5bpm)
and frequent (≥6bpm) premature contractions.
– Premature Atrial Contraction
Premature atrial contraction (PAC): It is a common fetal arrhythmia, which refers to that the
fetal rhythm. (c) Tissue Doppler spectrums of ventricular septal movement are obtained by placing sample volume at the lateral ventricular
septum of mitral/tricuspid annulus
atrial contraction is premature, following an
incomplete compensatory pause, which can be
conducted to the ventricle or blocked. The
appearance of a corresponding ventricular
movement represents that the PAC has conducted to the ventricle. Conversely, there is no
corresponding ventricular motion with a blocked
PAC. Both the above two characteristics are
shown if the PAC partly conducts to the ventricle (Fig.4.36).
M-mode echocardiography shows the premature
atrial motion wave with a low amplitude.
The Doppler echocardiography of PAC shows
that wave of the inow tract blood ow appears
in advance, similar to that in M-mode echocardiography. The wave of ventricular ejection will
appear if the PAC conducts to the ventricle. In
contrast, no wave of ventricular ejection will
appear if the PAC is blocked. It is challenging to
218
Q. Zhu et al.
a
b
c
Fig. 4.36 Fetal irregular arrhythmia (Premature Atrial Contraction).
(a) M-mode ultrasound shows the frequent atrial bigeminy caused by
PAC conducted to the ventricle. (b) Accidental blocked PAC and the
premature contraction of the atrial wall (arrow). (c) Spectrum Doppler
imaging shows the accidental blocked PAC and the premature contrac-
show the ventricular outow tract wave if the
atrial contraction is exceptionally in advance.
– Premature ventricular beat
Premature ventricular beat, originating from the
ventricle without conducting reverse to the
atrium, is uncommon in the fetus. It is characterized by the ventricular contraction premature
and long compensative interval, without corresponding atrial contraction.
M-mode echocardiography shows the premature
ventricular wave with a low amplitude. There is
no corresponding atrial wave in the anterior
region. A long interval can be shown in the
posterior of the premature ventricular wave,
which is longer than that of PAC (Fig.4.37).
The Doppler echocardiography of premature
ventricular beat shows that wave of the outow
tract blood ow appears in advance, without an
tion of the atrial wall (arrows). (References: Carvalho JS, Prefumo F,
Ciardelli V, et al. Evaluation of fetal arrhythmias from simultaneous
pulsed wave Doppler in pulmonary artery and vein. Heart, 2007,
93:1448–1453)
anterior wave of the inow tract blood ow, following by a long interval.
• Tachyarrhythmia
– Sinus tachycardia. The fetal heart rate ranges from
180 to 200bpm, with a 1:1 ratio of atrial: ventricular rhythm. The movement curves of the atrium and
ventricular wall are regular and corresponding.
– Supraventricular tachycardia. Supraventricular
tachycardia (SVT) refers to the fetal heart rate in
the 220 to 300bpm range, with 1:1 atrial: ventricular conduction. The motion curves of the atrial and
ventricular wall are corresponding and regular
(Fig.4.38).
– Ventricular tachycardia. Ventricular tachycardia
(VT) refers to the fetal ventricular rate>200bpm,
the ventricular rate>the atrial rate. The ventricular
movement curve is regular, while the atrial curve is
regular or irregular.
4 Ultrasonic Diagnosis ofFetal Heart
219
a
b
c
Fig. 4.37 Fetal irregular arrhythmia (Premature ventricular beat). (a)
In M-mode, the upper curve represents the ventricular wall, and the
lower one represents the atrial wall. The line in the middle is the motion
curve of the atrioventricular valve. The premature ventricular beat is
shown. (b) In the M-mode of fetal ventricular bigeminy, the upper curve
represents the atrial wall, the lower one represents the ventricular wall,
– Atrial utter. Atrial utter (AF) is dened as the
fetal atrial rate in the 300–500 bpm range, faster
than the rate of the ventricle. The movement curve
of the atrial wall is regular, and that of the ventricular wall is irregular (Fig.4.39).
– Atrial brillation. Fetal atrial brillation refers to
fetal atrial rate>400–500bpm, atrial rate>ventricular rate. Curves of the atrial wall and the ventricular wall are irregular (Fig. 4.40). Incessant
fetal tachyarrhythmia can lead to fetal heart failure,
hydrops, and even fetal demise.
• Bradyarrhythmia
– Sinus bradycardia. Fetal sinus bradycardia refers to
a fetal heart rate of 100bpm or less, with synchronized atrial and ventricular rate. Motion curves of
the atrial and ventricular walls are corresponding,
regular (Fig.4.41).
– Heart block. Normally, the distance between the
beginning of the atrial wave and that of the ven-
and the middle one is the motion curve of the ventricular septum. The
premature ventricular beat is shown. (c) The spectrum Doppler shows
the ventricular trigeminy in the fetus (References: Carvalho JS, Prefumo
F, Ciardelli V, etal. Evaluation of fetal arrhythmias from simultaneous
pulsed wave Doppler in pulmonary artery and vein. Heart, 2007,
93:1448–1453)
tricular wave in M-mode ultrasound or the A-V
interval in spectrum Doppler is within 150ms. The
heart block can be determined by estimating the
A-V interval by M-mode or spectral Doppler ultrasound (Fig.4.42).
First-degree heart block refers to the PR interval
is longer than 150ms. All the atrial contractions
are conducted to the ventricle (Fig.4.43).
Second-degree heart block
• Mobitz type I is characterized by the progressive
lengthening of the A-V interval in spectrum Doppler,
following by a heart block (short-long-long-drop)
(Fig.4.44).
• Mobitz type II refers to the regular A-V interval under
spectrum Doppler, with cyclical atrioventricular block.
No progressive prolonging PR interval is detected
(Fig.4.45).
• Third-degree atrioventricular block, also known as a
complete atrioventricular block (CAVB), is character-
220
ab
cd
Q. Zhu et al.
Fig. 4.38 Supraventricular tachycardia. (a) Doppler of supraventricular tachycardia. (b) M-mode ultrasound of fetal supraventricular tachycardia.
(c, d) M-mode color ultrasound in fetal supraventricular tachycardia
ab
Fig. 4.39 Fetal atrial utter. (a) M-mode ultrasound shows fetal atrial
utter with a 2:1 atrioventricular conduction, atrial rate> ventricular
rate. (b) It shows pulsed wave Doppler (PWD) recording of pulmonary
vessels (A) and M mode (B) of the same fetus with atrial utter and 2:1
atrioventricular block, simultaneously. The vertical dashed line shows
the corresponding atrial and ventricular activity both in the PWD and M
mode. (References: Carvalho JS, Prefumo F, Ciardelli V, et al.
Evaluation of fetal arrhythmias from simultaneous pulsed wave Doppler
in pulmonary artery and vein. Heart, 2007, 93:1448–1453)
4 Ultrasonic Diagnosis ofFetal Heart
221
ized by the fetal ventricular rate less than 80 bpm,
atrial rate >ventricular rate, and atrial and ventricular
dissociation (Fig.4.46).
• Notices in screening fetal arrhythmia.
Fig. 4.40 M-mode echocardiography of fetal atrial brillation, atrial
rate>ventricular rate
– When detecting fetal arrhythmia, M-mode echocar-
diography should simultaneously record the motion
curve of the atrial wall and the ventricular wall, and
calculate the atrial rate and ventricular rate, respectively. Dene the type of arrhythmia according to
the corresponding relationship between atrial and
ventricular rate and between atrial and ventricular
contraction.
– In Doppler echocardiography, place the sampling
volume at the intersection of the ventricular inow
and outow tract to obtain the spectral imaging of
the inow and outow tract, analyze, and determine the type of arrhythmia.
– The diagnosis of rst- to second-degree heart block
is based on the atrial and ventricular dissociation.
Besides, it depends on the PR interval by recording
the spectrum of the right pulmonary artery and
right superior pulmonary vein simultaneously, or
the spectrum of SVC and ascending aorta
simultaneously. These methods help to make a correct diagnosis of fetal rst- to second-degree atrio-
a
b
c
Fig. 4.41 Fetal sinus bradycardia. (a) M-mode ultrasound shows fetal bradycardia. (b) Spectrum Doppler ultrasound shows fetal bradycardia. (c)
Spectrum Doppler ultrasound shows fetal tachycardia changing into bradycardia, with alternating fast and slow heart rate
222
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Q. Zhu et al.
Fig. 4.42 Evaluation of the PR interval (A-V interval in the gure) by
the method of simultaneous spectrum Doppler A-V interval (a) and
recording the spectrum of pulmonary artery and vein (b). References:
Fig. 4.43 Spectrum Doppler of rst-degree heart block shows AV
interval>150ms. References from: Carvalho JS, Prefumo F, Ciardelli
V, et al. Evaluation of fetal arrhythmias from simultaneous pulsed wave
Doppler in pulmonary artery and vein. Heart, 2007, 93:1448–1453
Carvalho JS, Prefumo F, Ciardelli V, etal. Evaluation of fetal arrhythmias from simultaneous pulsed wave Doppler in pulmonary artery and
vein. Hear, 2007, 93:1448–1453
Fig. 4.45 The second-degree heart block, type II. In M-mode, the
upper curve represents the ventricular wall, and the lower one represents the atrial wall. The line in the middle is the motion curve of the
ventricular septum and the atrioventricular valve. The atrial wave beats
regularly, and the ventricular wave stops once after three pulsations,
indicating a cyclical atrioventricular block
ventricular block or dominant preexcitation
syndrome.
– It is transient when the arrhythmia duration
Fig. 4.44 Second-degree heart block, type I. This simultaneous SVC/
AA Doppler recording shows the venous waves are below the zerovelocity line and the aortic waves above the line. A tall “A” wave is
superimposed on the aortic wave. The progressive lengthening of the
AV time intervals from 280 to 353 ms leads to a complete block,
observed in a classical Luciani–Wenckebach phenomenon. It should be
noted that the A-A interval remains constant at 391 ms. (References:
Fouron JC. Fetal arrhythmias: the Saint-Justine hospital experience.
Prenat Diagn, 2004, 24:1068–1080.)
<10min. Premature more than 10bpm is dened as
frequent premature. The transient bradycardia,
tachycardia, and occasional premature are normal
variations, which are kinds of immature functional
changes. They may repeatedly occur in heart development and then disappear. No particular treatment
is needed.
4 Ultrasonic Diagnosis ofFetal Heart
223
a
b
c
Fig. 4.46 Bradyarrhythmia. (a) Spectral Doppler ultrasound shows
that the atrial and ventricular dissociation without dependence. (b)
M-mode color ultrasound shows that the movement curves dissociation
– The type of arrhythmia varies with pregnancy, so
does the severity of arrhythmia. The earliest diagnosis time of fetal arrhythmia is about 16weeks,
while the best diagnosis time is 18–22weeks. For
the early detection of fetal pathological arrhythmia,
fetal heart auscultation should be carried out carefully in the middle of pregnancy, especially in the
16–20 weeks. These actions contribute to further
clinical diagnosis, avoiding the delay of optimal
diagnosis and treatment.
of the atrial and ventricular wall, without correlation. Picture a and picture b are from the same fetus, suggesting CAVB. (c) The separation of
the atrial and ventricular motion curves, uncorrelated and independent
Suggested Reading
1. Carvalho JS, Prefumo F, Ciardelli V, et al. Evaluation of fetal
arrhythmias from simultaneous pulsed wave doppler in pulmonary
artery and vein. Heart. 2007;93:1448–53.
2. Fouron JC.Fetal arrhythmias: the saint-Justine hospital experience.
Prenat Diagn. 2004;24:1068–80.
3. Hofstaetter C, Hansmann M, Sturla H.Eik-nes, etal. A cardiovascular prole score in the surveillance of fetal hydrops. J MaternalFetal Neonatal Med. July 2006;19(7):407–13.