Examination Of Fetal Heart Research Articles

EP04.05: Applicability of ISUOG practice guidelines on second trimester sonographic screening examination of fetal heart

To study the applicability of ISUOG practice guidelines on sonographic examination of fetal heart during second-trimester screening. A six month period (July- December 2016) prospective observational study was designed to evaluate singleton pregnancies between 20th and 22ndGW. 327 fetuses were examined. Cases with congenital heart malformation were excluded. Each parameter of the ISUOG heart protocol was scored for accuracy and characterised as adequately or non-adequately assessed by a qualified specialist who performed all examinations. 4 chamber view was adequately imaged in 98.8% of cases (n=323), while left outflow tract imaging was ideal in the total of examined parameters only in 41% of cases (n=134). A right outflow tract sufficient view was in 60.6% of cases (n=198) possible, while three vessel and trachea were characterised as satisfactorily visualised for all examined parameters in 67.6% of cases (n=221). When studying the different 31 parameters included in ISUOG protocol, there were only 5 which seem to be frequently involved in insufficient assessment. These parameters were: AV-valves offsetting (83% adequacy), septoaortic continuity with clear imaging of the aortic root (78.4% adequacy), clear wall demonstration of 3 distinct vessels in 3VTV (67.8% adequacy), detailed pulmonary branching (65.7% adequacy) and optimal visualisation of myocardiac / endocardiac tissue (55.9% adequacy). By excluding those 5 parameters, rate of adequate imaging was raised to 99.2% for 4 chamber view, 98.4% for left outflow tract view,73.8% for right outflow tract view, and 99.2% for three vessel and trachea view. Applicability of most parameters included in ISUOG practice guidelines concerning sonographic screening examination of fetal heart in 2nd trimester is feasible. Myocardiac / endocardiac tissue, AV-valves offsetting, septoaortic continuity, pulmonary artery bifurcation and clear vessel wall borders in 3VTV are indicated to be the parameters which can be characterised as often being inadequately imaged.

P27.09: Diagnostic accuracy of basic fetal heart examination at 11–13 weeks' gestation of pregnancy

Investigate the diagnostic performance of a simplified fetal heart examination in a routine setting of first trimester ultrasound screening for aneuploidies. This was a prospective observational study, in which a basic cardiac examination applying the cross-sections of the 4-chamber and/or 3-vessels views using colour Doppler was performed at the 11 to 13 weeks' gestation scan in a routine setting in single pregnancies. A total of 1850 single fetuses performed first and second trimester ultrasound scans between January 1st 2016 and January 13th 2017. Overall, 1799 cases with second trimester scan, echocardiography or autopsy findings were included. In 1177 cases (65.4%) basic heart examination was not performed during first trimester because of difficult fetal position, maternal obesity with inadequate visualisation of the heart structures or when the examiner was not comfortable with early heart examination. Patients with incomplete anatomy scan at second trimester and with unknown outcome were excluded. In 622 cases (34.5%) a basic cardiac examination applying the cross-sections of the 4-chamber and / or 3-vessels views using colour Doppler was carried out. In total, there were 16 cases with a confirmed congenital heart defect (0.89%) and 16 cases of fetuses with chromosomal abnormalities. Evaluation by the 4-chamber and/ or 3 vessels view had a sensitivity and specificity of 66.7% and 99.5% respectively, with a positive and negative predictive values of 85.7% and 99.5%, respectively. Overall, at our unit, 37.5% of the cardiac malformations were detected at first trimester scan. Major heart anomalies such as hypoplastic left heart syndrome, pulmonary hypoplasia, transposition of the great vessels and atrioventricular septal defect were depicted at the 11-13 weeks' scan by performing basic heart evaluation. Basic heart views allow for selection of 67% cases with major cardiac malformations at the 11 to 13 weeks' routine ultrasound scan, providing the option for early confirmation by echocardiography.

EP04.12: Parameters affecting imaging accuracy on sonographic screening examination of fetal heart during second trimester according to ISUOG practice guidelines

EP04.12: Parameters affecting imaging accuracy on sonographic screening examination of fetal heart during second trimester according to ISUOG practice guidelines

P27.07: Feasibility of basic fetal heart imaging during first trimester

Prospective study to evaluate the feasibility of obtaining standard basic fetal heart images during routine first trimester screening. From January 2010 up to December 2016 (7 years), 4518 pregnant women were examined for the purposes of the 1st trimester analytical sonogram. Singleton pregnancies, after spontaneous conception or as a result of IVF were included. All fetuses were characterised as low risk for congenital heart defects. Mothers' average age was 32.4 years (17-43). Mothers' average BMI was 24.8 (18.1-41). The gestational age during examination was on average 12+5 weeks (11+0-13+6), the CRL 64mm (46-81). Attempts were made to image the four-chamber view, the interventricular septum, the outflow and the cross-over of the great vessels and the transverse imaging of the 3 vessels-trachea in the upper part of the thorax. B-mode and bidirectional colour Doppler flow imaging were used in all cases. All images were reviewed offline and evaluated directly after every examination. Fetuses with well-visualised but atypical images were excluded. The sonographic access was transabdominal (82%; 3705/4518), transvaginal (2%;90/4518) or both (16%;723/4518). A satisfactory imaging of a normal fetal cardiac four-chamber view was achievable in 87% (3930/4518) and of a normal transverse three vessel-trachea view in 83% (3750/4518) of the cases (in 13% / 17% technically not feasible). Overall in both, 4CV- and 3VT-view, satisfactory visualisation was obtained successfully in 79% (3570/4518) of fetuses with typical first trimester heart images. The mean additional duration of the examination was less than four minutes (1.3-8.8) if the fetus was lying in the typical for NT-measurement neutral position. The attempt of an early sonographic imaging of the fetal cardiac anatomy is very important for a timely prenatal diagnosis of major congenital heart diseases. The examination conditions are often difficult and require well-experienced examiners. It is feasible to perform basic fetal heart examination during routine first trimester screening.

Effect role of initial planes on the examination of fetal heart by four-dimensional echocardiography with spatiotemporal image correlation

Objective To investigate whether different initial planes have an effect on examination of the fetal heart by four-dimensional ultrasound with spatiotemporal image correlation (STIC). Methods The standard examination planes of fetal heart were rendered using the heart volume data which were acquired in different initial planes with STIC, then these rendered planes were compared and scored. Results ① At the four-chamber initial planes, the reconstruction rate of longitudinal planes of the aortic arch (46.27%) and the pulmonary artery (49.25%) were poor, in addition, the reconstruction showed low quality, and the average scores were 1.366 and 1.403, respectively. ② At the left outflow-tract initial planes, reconstruction rates of all planes were above 75%, and there was no statistical difference(P=0.169). Each reconstruction plane had good score, even if the scores of longitudinal planes of the aortic arch/pulmonary artery were low, whose scores reached 1.936 and 2.051, respectively. ③ At the initial longitudinal planes of the aortic arch, the reconstruction rate (96.67%) and average reconstruction score (2.617) of longitudinal planes of the pulmonary artery were obviously higher than those of other planes. ④ Compared with different initial planes, volume data acquired from left outflow-tract initial planes could lead to high-quality reconstructed planes of all standard examination planes. While four-chamber initial planes acquired high-quality standard examination planes except longitudinal planes of the aortic arch and pulmonary artery. Volume data from initial longitudinal plane of the aortic arch acquired low-quality standard examination planes except longitudinal planes of the aortic arch and longitudinal plane of the pulmonary artery. Conclusions With STIC, sonographers can not only save the volume data for off-line analysis and remote consultation but also choose the better initial planes for themselves during the examination of fetal hearts. Key words: Echocardiography, four-dimensional; Fetal heart; Initial planes; Spatiotemporal image correlation

Double-outlet of Right Ventricle of Recipient Fetus in Severe Mid-trimester Twin–Twin Transfusion Syndrome

ABSTRACT A 37 years old Thai pregnant woman with MCDA twins, para 1, was suspected of severe twin-twin transfusion syndrome (TTTS) at 21 weeks’ of gestation. Quintero staging was applied in this cases. Neither of the fetuses exhibited signs of hydrops. Abnormal four-chamber view was demonstrated in a recipient fetus. Two-dimensional and color Doppler showed complex cardiac malformations which include (1) hypoplastic left ventricle, and (2) large atrial septal defect, (3) atretic tricuspid valve, and (4) the blind right atrium communicating with the left atrium through the ostiumprimum defect. For more information, threedimensional (3D) echocardiography was used toreconstruct“thin slab” of the fetal heart and its outflow tracts. A double-outletright ventricle (DORV) was highly suspicious. Congenital cardiac anomaly can decompensate the compromised myocardium of the recipient fetus. In addition to conventional 2D echocardiography, the application of advanced 3D echocardiography with ‘thin slab’ technique can help for the examination of fetal heart. How to cite this article Panchalee T, Wataganara T. Doubleoutlet of Right Ventricle of Recipient Fetus in Severe Midtrimester Twin–Twin Transfusion Syndrome. Donald School J Ultrasound Obstet Gynecol 2016;10(4):365-366.

Matrix array transducer for the examination of fetal heart

The X6-1 xmatrix array transducer allows a completely new approach to the diagnostic ultrasound: it permits visualization of fetal heart in real time, without the need for gating, and it is unaffected by motion artefacts. It is obtained in real time, without any spatial reconstruction. The authors compared this technology with the traditional one in two case reports: a diagnostic doubt of small muscular ventricular septal defect was solved using this new technique; a diagnosis of complete atrioventricular septal defect was confirmed. Three-dimensional real-time imaging would seem very precise in the study of fetal heart: the defects were fully visualized from any angulations. This new technology is promising but from the authors' limited experience, there is no evidence to use it in routine practice. It should be very useful to commence a prospective study on fetuses at risk while testing the superiority of this technique.

OP26.09: Comparison of first trimester to second trimester fetal heart examination in detection of cardiac anomalies in a tertiary fetal medicine teaching unit

<scp>OP</scp>26.09: Comparison of first trimester to second trimester fetal heart examination in detection of cardiac anomalies in a tertiary fetal medicine teaching unit

Low-frequency high-definition power Doppler in visualizing and defining fetal pulmonary venous connections.

The use of low-frequency high-definition power Doppler in assessing and defining pulmonary venous connections was investigated. Study A included 260 fetuses at gestational ages ranging from 18 to 36weeks. Pulmonary veins were assessed by performing two-dimensional B-mode imaging, color Doppler flow imaging (CDFI), and low-frequency high-definition power Doppler. A score of 1 was assigned if one pulmonary vein was visualized, 2 if two pulmonary veins were visualized, 3 if three pulmonary veins were visualized, and 4 if four pulmonary veins were visualized. The detection rate between Exam-1 and Exam-2 (intra-observer variability) and between Exam-1 and Exam-3 (inter-observer variability) was compared. In study B, five cases with abnormal pulmonary venous connection were diagnosed and compared to their anatomical examination. In study A, there was a significant difference between CDFI and low-frequency high-definition power Doppler for the four pulmonary veins observed (P<0.05). The detection rate of each pulmonary vein when employing low-frequency high-definition power Doppler was higher than that when employing two-dimensional B-mode imaging or CDFI. There was no significant difference between the intra- and inter-observer variabilities using low-frequency high-definition power Doppler display of pulmonary veins (P>0.05). The coefficient correlation between Exam-1 and Exam-2 was 0.844, and the coefficient correlation between Exam-1 and Exam-3 was 0.821. In study B, one case of total anomalous pulmonary venous return and four cases of partial anomalous pulmonary venous return were diagnosed by low-frequency high-definition power Doppler and confirmed by autopsy. The assessment of pulmonary venous connections by low-frequency high-definition power Doppler is advantageous. Pulmonary venous anatomy can and should be monitored during fetal heart examination.

Advances in fetal cardiology

The prevalence of congenital heart malformations as a whole (including diseases of little clinical significance) is 0.8% (8 of 1000 live births). The most frequent pathologies are malformations that prevent blood from reaching the lungs to take oxygen or block the normal supply of oxygenated blood to the body. The transposition of the great vessels (the aorta and pulmonary artery originate from the ‘wrong’ ventricles) is important as it represents the most severe neonatal heart disease. A separate issue, instead, is that of arrhythmias. The diagnosis is made around the 20th–21st week of gestation through a targeted ultrasound examination of fetal heart. This enables the recognition of the vast majority (around 85%) of clinically important congenital heart diseases (CHD) at birth. Nevertheless, targeted examinations are not possible for all pregnancies: the costs would not allow it. They are still available for patients who have recognized risk factors (they had children with previous CHD, they took teratogenic drugs, or they have diabetes), whereas pregnant women who have a very low risk are subjected to basic ultrasound examinations. An ultrasound examination allows at least suspicion of a significant proportion (30–40%) of important heart diseases. Progresses in the diagnostic field are continuous and the development of visualization techniques provides great opportunities. Four-dimensional (4-D) ultrasound that allows volumetrical viewing of the fetus, moving, to the most detailed facial expressions, appears to be promising in the diagnosis of CHD, which often escape the traditional ultrasound examination. Enabling better visualization of the heart, thanks to the ability to view it from different points and angles, volumetric ultrasound could aid the diagnosis of more heart diseases. Recognition of fetuses with heart disease may be useful for planning targeted interventions. The purpose of prenatal diagnosis is, first, to improve the prognosis without serious damages in the neonatal period. If necessary, there is the possibility of interventions on the fetus (which mainly consists of aortic or pulmonary valve and foramen ovale dilation), but they are still experimental cardiac procedures. In general, the first interventions take place on the newborn baby; therefore, the birth can be arranged at a cardiology and cardiac surgery unit, thus avoiding delays and dangerous transfers. Thanks to the timely diagnosis, today, 90% of operated babies survive and reach adulthood with a normal life expectancy (only for patients with univentricular heart, we impose limits on physical and working activity). Today, complex operations are possible even in low-birth-weight babies, with very good results, attempting to prioritize corrective radical rather than palliative solutions, which until recently were often the only options. As medical therapies play a marginal role in heart malformations, they are instead essential in the treatment of fetal tachyarrhythmias: these are quite rare diseases, which are also detectable by echocardiography, often isolated (i.e. not associated with cardiac malformations). These arrhythmias in the fetus are rapidly fatal if not effectively controlled and treated with specific drugs administered to the mother, so that in most cases, they resolve easily, without future problems.

Cardiac auscultation: Preliminary findings of a pilot study using continuous Wave Doppler and comparison with classic auscultation

Routine fetal heart examination is performed in the obstetric office using a portable continuous Wave Doppler (CWD) device [ [1] Brown A.D. Robertson J.G. The ultrasonic Doppler cardioscope in obstetrics. J Obstet Gynaecol Br Commonw. 1968 Jan; 75: 92-96 Crossref PubMed Scopus (5) Google Scholar ], which produces sounds but not images. We explored the heart in adult patients using this method and we found it to be surprisingly informative. We decided then to define cardiac auscultation points and typical auditive patterns for the procedure. After that, we compared this method with classic auscultation (CA) in cardiologic patients, using color Doppler echocardiography (CDE) as a gold standard.

OP26.01: Post‐mortem examination of fetal heart in the first half of the pregnancy: a comparison of high‐field MRI at 9.4 T to lower‐field MRI and to autopsy

OP26.01: Post‐mortem examination of fetal heart in the first half of the pregnancy: a comparison of high‐field MRI at 9.4 T to lower‐field MRI and to autopsy

OP15.09: Comparison of real‐time three‐dimensional echocardiography and spatio‐temporal image correlation in assessment of fetal interventricular septum

pulmonary vein was further to interatrial septum from the 4-chamber view, connected with left atrium obliquely. The left inferior pulmonary vein was close to descending aorta from 4-chamber view, connected with left atrium vertically. The left inferior pulmonary vein was located to anterior descending aorta from aortic arch view, and formed 90◦ angel with descending aorta. The right superior pulmonary vein was close to apical right atrium and superior vena cava from 4-chamber view, connected with left atrium. The right inferior pulmonary vein was near to spine, parallelled to interatrial septum, connected with left atrium. Conclusions: There is an advantage in visualizing and locating in fetal pulmonary veins by EFI combine with 2 dimensional echocardiography. Pulmonary veins anatomy should be checked during fetal heart examination.

Sonographic Finding of Aberrant Truncal Origin of the Left Carotid Artery: An Almost Unkown Abnormality of the Aortic Arch

During detailed anomaly scan at 20 weeks of pregnancy, we examine the fetal body, structure and position of the placenta and measure fetal growth and amount of amniotic fluid. An important part of the detailed scan is the examination of fetal heart and connecting vessels. Assessment of the aortic arch by ultrasound can discover malformations of this and leaving vessels.

Fetal cardiac function assessed by spatio-temporal image correlation

Three-dimensional (3D) and four-dimensional (4D) ultrasound have been proposed to be valuable tools for the examination of fetal heart. Spatio-temporal image correlation (STIC) is a technique that adds a time component to 3D ultrasound imaging of the fetal heart, so we can evaluate cardiac structures as a 4D cine sequence containing information of one full cardiac cycle. STIC gives the investigator the opportunity to freeze the displayed cardiac loop in end-diastolic and end-systolic phases. By STIC, 3D measurements of both the left and right ventricle can be used to calculate fetal heart stroke volume, cardiac output and ejection fraction, and expressions of cardiac function. The ultimate goal of STIC technique is to improve fetal cardiac function analysis by decreasing the dependency on operator skills required by two-dimensional ultrasound. In this article, we describe literature practical approach for the examination of the fetal heart function using 4D ultrasound by STIC technique.

OC195: Evaluation of perinatal condition in newborns with elevated concentration of cord cardiac troponin I

To assess the results of fetal examination and neonatal condition in cases with elevated cord cardiac troponin I concentration. Cardiac troponin I (cTnI) is a specific marker of myocardial injury in adults and children. Perinatal asphyxia can cause cardiac dysfunction. Some 161 samples among fetuses from pathological pregnancies were collected. Twenty-two had an elevated level of cTnI (above 0.1 ng/mL). Disorders in pregnancy, date of gestation, Doppler flow velocimetry in the ductus venosus (DV) and umbilical artery (AU) and vein (DV), mode of delivery, Apgar score and respiratory status after birth were evaluated. cTnI was determined on a dimension clinical chemistry system. There were 22 newborns with a raised level of TnI: seven (31.8%) with SGA, five (22.2%) with fetal cardiac problems (arrhythmia, structural and functional abnormalities), nine (40.9%) with abnormal biophysical test results (abnormal Doppler velocimetry, computerized cardiotocography, biophysical profile score) and six (27.2%) whose mothers who had disorders (diabetes mellitus, hypertension). Results are shown in the table. Median gestational age at delivery was 36.6 (range, 27–43) weeks. Seventeen (77.2%) patients had a Cesarean section. The range of TnI blood concentration was 0.11–6.66 ng/mL in this group. Five (22.7%) had umbilical pH below 7.25. A high level of cTnI was associated with several disorders that could have led to fetal asphyxia. More detailed fetal heart examination is necessary to prove that fetal asphyxia had an impact on heart function.

OC196: The contribution of CNTI‐SonoVue in the classification of adnexal masses as benign or malignant: a multicenter study

I concentration. Cardiac troponin I (cTnI) is a specific marker of myocardial injury in adults and children. Perinatal asphyxia can cause cardiac dysfunction. Methods: Some 161 samples among fetuses from pathological pregnancies were collected. Twenty-two had an elevated level of cTnI (above 0.1 ng/mL). Disorders in pregnancy, date of gestation, Doppler flow velocimetry in the ductus venosus (DV) and umbilical artery (AU) and vein (DV), mode of delivery, Apgar score and respiratory status after birth were evaluated. cTnI was determined on a dimension clinical chemistry system. Results: There were 22 newborns with a raised level of TnI: seven (31.8%) with SGA, five (22.2%) with fetal cardiac problems (arrhythmia, structural and functional abnormalities), nine (40.9%) with abnormal biophysical test results (abnormal Doppler velocimetry, computerized cardiotocography, biophysical profile score) and six (27.2%) whose mothers who had disorders (diabetes mellitus, hypertension). Results are shown in the table. Median gestational age at delivery was 36.6 (range, 27–43) weeks. Seventeen (77.2%) patients had a Cesarean section. The range of TnI blood concentration was 0.11–6.66 ng/mL in this group. Five (22.7%) had umbilical pH below 7.25. Conclusions: A high level of cTnI was associated with several disorders that could have led to fetal asphyxia. More detailed fetal heart examination is necessary to prove that fetal asphyxia had an impact on heart function.

Fetal echocardiographic screening in twins for congenital heart diseases

Congenital heart disease (CHD) is the most common congenital disorder at birth. Yagel and colleagues's method of heart examination has been proved valuable in finding CHD prenatally in single pregnancies. The aim of this study was to analyze the frequency of CHD in twin pregnancies and the sensitivity of the method. A total of 1103 pregnant women with twins were enrolled in this study, including 127 cases with high-risk for CHD. Five transverse ultrasound measurements were used for fetal heart examination, including the upper abdomen view, four-chamber view, five-chamber view, pulmonary artery bifurcation view, and three-vessel view. In the fetuses who were diagnosed with CHD and whose parents requested termination of the pregnancy, autopsy of the fetal heart was performed after an abortion, and a blood sample was collected from the heart for chromosome evaluation. In the other fetuses, a close follow-up was conducted by echocardiography within one year after birth. Antenatally, CHD was found in 12 twins, of which 4 were from the high-risk group (3.15%), and 8 from the low-risk group (0.82%). In 2 pairs of the twins, the two fetuses had a same kind of CHD (one pair had tetralogy of Fallot (TOF), another pair had rhabdomyoma). Another pair had different types of anomaly (one fetus had TOF, and the other duodenal atresia with a normal heart). Termination of pregnancy was performed in these three pairs and the autopsy of the fetal heart confirmed the ultrasound findings. In the other 9 pairs, CHD was detected in one fetus, and a normal heart in the others. In the cases who received chromosome evaluation, 2 had abnormal chromosomes. During the follow-up after birth, heart examinations confirmed the prenatal diagnosis in 7 of the 9. The diagnosis of CHD was missed antenatally in 2 pairs of twins. In both the cases, one fetus was normal, and the other was confirmed as having CHD after birth (small ventricle septum defect in one, and persistent open ductus arteriosus in the other). Thus, the total frequency of CHD was 16 (7.3/1000), which was similar to that in single pregnancies. The sensitivity of fetal echocardiography was 87.5% and the specificity was 100%. The frequency of CHD is the same in twin as in single pregnancies. Systemic ultrasound scanning with five transverse views is effective in diagnosing fetal CHD in twin pregnancies.

OP09.18: The value of three‐dimensional extended imaging for fetal heart examination

The aim of the study was to assess the value of a novel ultrasound package, named three-dimensional extended imaging, which is composed of Multi-Slice View (MSV) and Oblique View (OBV) modes, for fetal heart structures evaluation (for the volume fetal echocardiography). 62 women with physiological pregnancy in terms of 20–36 weeks were examined with the ultrasound system (Accuvix XQ, Medison, Korea) equipped with the 3D XI technology. 62 static volume recordings of the normal fetal heart were analyzed off-line in the study. A complete fetal heart examination was successful in 48 (77.4%) cases. It was impossible to evaluate 14 (22.6%) of cardiac volume data because of unsatisfactory image quality. MSV allowed approaching to the cardiac images by slicing and manipulating the volume data. OBV, with its ability to cut and move images inside the acquired volume, permitted creating images of fetal circulation, which may be difficult to obtain with conventional 2DUS. 48 cardiac recordings were used for intracardiac structures and great outflows' identification. In our preliminary study we were able to get following fetal heart views with the help of MSV and OBV: main pulmonary artery—in 42 (87.5%) cases, left outflow tract—in 34 (70.8%), 3 vessel view—in 38 (79.2%), aortic arch—in 36 (75%), ductal arch—in 21 (43.8%), superior and inferior veins cava—in 19 (39.6%), ‘in-plane’ of ventricular septum—in 100%. With the help of this new technology it was possible to create standard and nonstandard echocardiographic views from the only single volume.

The examiner's ultrasound experience has a significant impact on the detection rate of congenital heart defects at the second‐trimester fetal examination

To determine whether training and experience in performing ultrasound examinations are factors that influence the prenatal detection of congenital heart defects (CHDs) in a non-selected population, in order to evaluate and improve the current training program. All pregnant women who received a routine second-trimester ultrasound scan by a sonographer/midwife and delivered at our hospital between February 1991 and December 2001 were registered prospectively. Less experienced sonographer/midwives who had performed between 200 and 2000 routine examinations were compared with experienced sonographer/midwives who had carried out more than 2000 examinations. During the first 5 years of the study the heart structures obtained were registered in detail. Of 29,035 fetuses, 35/82 (43%) major CHDs were prenatally detected at the routine examination. The experienced sonographer/midwives obtained both the four-chamber view and the great arteries in 75%; the figure for the less experienced sonographer/midwives was 36% (P < 0.001). The differences in detecting major heart defects were 22/42 (52%) and 13/40 (32.5%), isolated CHDs 8/18 (44%) and 6/22 (27%) and CHDs with associated malformations 14/24 (58%) and 7/18 (39%), respectively. In both groups some CHDs with an abnormal four-chamber view were missed, although the experienced sonographer/midwives recognized significantly more of the abnormal views than did the less experienced sonographer/midwives (P = 0.002). Experience has a significant impact on the examination of the fetal heart and the prenatal detection rate of major CHDs. To avoid a relatively long learning curve, ultrasound education needs to intensify the teaching of the basic four-chamber view. The great arteries should be included after additional training. Those basic views of the fetal heart must be mastered before new views and advanced technology are added to the fetal heart examination.