EDITORIAL

367

Ultrasound Obstet Gynecol

2001;

17

: 367–369

Blackwell Science, Ltd

Editorial

Editorial

Examination of the fetal heart by five short-axis views: a proposed screening method for comprehensive cardiac evaluation

S. YAGEL, S. M. COHEN and R. ACHIRON*

Department of Obstetrics and Gynecology, Hadassah University Hospital, Mt. Scopus, Jerusalem and *Department of Obstetrics and

Gynecology, Chaim Sheba Medical Center, Tel Hashomer, Israel

Fetal cardiac malformations, with an incidence of 8 : 1000among livebirths, are the most common congenital malforma-tions. Their incidence is 6.5 times greater than chromosomalanomalies and 4 times that of neural tube defects. Further-more, 4 : 1000 livebirths will be affected by severe congenitalcardiac malformations which account for 20% of neonataldeaths and up to 50% of infant deaths attributed to congenitalanomalies

1–4

. There is therefore a clear rationale for includ-ing complete fetal echocardiography in every targeted organscan.

Moreover, nuchal translucency screening has been shownto be very effective in identifying fetuses at increased risk forboth chromosomal anomalies and cardiac malformation.Three to five percent of tested fetuses will be defined as beingat high risk for congenital heart disease following nuchaltranslucency examination

5–7

. This creates a new populationof considerable size that would be candidates for completefetal echocardiography. Centers offering nuchal translucencyscreening would therefore be expected to complement thiswith comprehensive echocardiography.

Though hailed as innovative and effective at its introduction,the four-chamber view of the fetal heart, when used alone asa screening tool, reveals only some cardiac anomalies

8–13

.Faced with discouraging false-negative rates, many centersintroduced scanning of the great vessels’ outflow tractsas part of their screening programs. This improved detec-tion rates. Most recently, some centers have started to includeextensive fetal echocardiography as part of all targeted organscanning, with significantly higher detection rates for cardiacmalformations

8–13

. In 1998 the AIUM (American Institute ofUltrasound in Medicine) published a technical bulletin

14

which put forth the institute’s recommendation for stand-ardizing fetal echocardiography. Our method is a naturalprogression from this methodology, with several advantages:the AIUM recommends 18–22 weeks’ gestation as optimaltiming for fetal cardiac examination, while our method isamenable to early second-trimester transvaginal ultrasound;ours includes scanning of the mediastinum; we propose thatfetal echocardiography be offered to all gravidae presentingfor routine screening.

The challenge today is to create a comprehensive and precisemethod to streamline fetal echocardiography. Traditionally,

fetal echocardiography has relied on several short- and long-axis views of the fetal heart. Fetal lie may enable optimal visual-ization of the short-axis views, but make the long-axis planesdifficult or impossible to obtain, or vice versa. Often the onlyrecourse is to wait for the fetus to turn. This of course lengthensexamination times considerably. The most difficult and time-consuming portion of the fetal echocardiographic examinationis the visualization of the aortic arch, which on the one handis indispensable in the diagnosis of aortic malformations, andon the other places the greatest demands on the sonographer,both in degree of difficulty and time required. These obstaclesare particularly problematic in busy screening programs.

To improve and simplify comprehensive fetal heart exam-ination, we suggest a fetal echocardiographic examinationbased on five transverse planes. The first and most caudalplane is a transverse view of the upper abdomen: movingcephalad. The next is the traditional four-chamber view,which remains the key to the fetal echocardiographic exam-ination. The third is the plane commonly termed the five-chamber view, in which the aortic root is visualized. Thefourth transverse view reveals the bifurcation of the pulmon-ary arteries. Yoo et al

15,16

suggested the three-vessel viewof the fetal upper mediastinum, a cross-sectional view of themajor vessels, as a quick and accurate method to identify thegreat vessels and diagnose certain anomalies. However,

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Figure 1

The five short-axis views for optimal fetal heart screening. The color image shows the trachea, heart and great vessels, liver, and stomach with the five planes of insonation superimposed. Polygons show the angle of the transducer and are assigned to the relevant gray-scale images (LT, left; RT, right) (I) The most caudal plane, showing the fetal stomach (ST), cross-section of the abdominal aorta (AO), spine (SP) and liver (LI). (II) The four-chamber view of the fetal heart, showing the right and left ventricles (RV, LV) and atria (RA, LA), foramen ovale (FO), and pulmonary veins (PV) to the right and left of the aorta (AO). (III) The ‘five-chamber’ view, showing the aortic root (AO), left and right ventricles (LV, RV) and atria (LA, RA), and a cross-section of the descending aorta (AO with arrow). (IV) The slightly more cephalad view showing the main pulmonary artery (MPA) and the bifurcation of left and right pulmonary arteries (LPA, RPA) and cross-sections of the ascending and descending aortae (AO and AO with arrow, respectively). (V) The 3VT plane of insonation, showing the pulmonary trunk (P), proximal aorta ((P)Ao), ductus arteriosus (DA), distal aorta ((D)Ao), superior vena cava (SVC) and the trachea (T).

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Editorial Yagel et al.

the aortic arch and trachea were not included, the formerbeing perhaps the most demanding aspect of fetal heart exam-ination. Following Yoo, we recently presented

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the threevessel and trachea (3VT) plane of insonation as the fifthshort-axis view in fetal echocardiography, to complement thefour traditional planes currently in use and facilitate andexpedite thorough fetal heart examination. The 3VT is themost cephalad transverse view, visualized on a plane crossingthe fetal upper mediastinum. It is easily obtained by movingthe transducer cephalad and slightly oblique from the four-chamber view. When properly executed, the 3VT reveals themain pulmonary trunk in direct communication with theductus arteriosus. A transverse section of the aortic arch isseen to the right of the main pulmonary trunk and ductusarteriosus. Cross sections of the superior vena cava and, pos-terior to it, the trachea, are visualized (Figure 1).

We recently demonstrated the clinical applicability of the3VT (submitted): in 99% of patients this view was quicklyand easily obtained from the familiar four-chamber view. Itsuse shortened the time required to examine the aortic arch,the most time-consuming aspect of fetal echocardiography.We consider one of the greatest advantages of our novelapproach the ease with which the examiner can scan the fetalheart, beginning with the caudal upper-abdomen view. Bysliding the transducer cephalad in one continuous motion, allthe pertinent views are readily visualized.

In our center we demonstrated that five short-axis viewsincluding the 3VT, simplified and streamlined fetal cardiacexamination, without compromising diagnostic effectiveness.We see it as another step in the integration of complete fetalechocardiography in routine targeted organ studies.

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UltrasoundObstet Gynecol

2000; Abstracts of the 10

th

World Congress onUltrasound in Obstetrics and Gynecology (Zagreb, October 2000):WS06–07

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