Cardiac Axis Deviation in Anomaly Scan: A Marker for Underlying Cardiac Anomalies.

Cardiac screening examination of the fetus: guidelines for performing the ‘basic’ and ‘extended basic’ cardiac scan

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. isuog GUIDELINES ISUOG Practice Guidelines (updated): fetal cardiac screening The International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) is a scientific organization that encourages sound clinical practice and high-quality teaching and research related to diagnostic imaging in women's healthcare. The ISUOG Clinical Standards Committee (CSC) has a remit to develop Practice Guidelines and Consensus Statements as educational recommendations that provide healthcare practitioners with a consensus-based approach, from experts, for diagnostic imaging. They are intended to reflect what is considered by ISUOG to be the best practice at the time at which they are issued. Although ISUOG has made every effort to ensure that Guidelines are accurate when issued, neither the Society nor any of its employees or members accepts liability for the consequences of any inaccurate or misleading data, opinions or statements issued by the CSC. The ISUOG CSC documents are not intended to establish a legal standard of care, because interpretation of the evidence that underpins the Guidelines may be influenced by individual circumstances, local protocol and available resources. Approved Guidelines can be distributed freely with the permission of ISUOG (

In a 14-month period, 409 women with singleton gestations referred for perinatal ultrasound consultation underwent evaluation of the fetal cardiac axis. Cardiac and intrathoracic anomalies were confirmed either by neonatal echocardiography or autopsy. Overall, 32 fetuses had an abnormal axis (nine, smaller axis than normal; 23, larger axis than normal). Of the 29 found to have cardiac (n = 24) or intrathoracic (n = 5) anomalies, 23 had an abnormal axis. The median cardiac axis of the normal group (44.0 degrees) was significantly smaller than that of the cardiac/intrathoracic anomaly group(60.0 degrees) (p = 0.002). The cardiac axis was independent of gestational age. The mean interobserver variation was 1.3 +/- 1.8 degrees. The sensitivity of an abnormal axis (< 28 degrees or > 59 degrees) in detecting congenital heart disease or intrathoracic anomalies was 23/29 (79.3%), with specificity of 371/380 (97.5%), positive predictive value of 23/32 (71.9%), and negative predictive value of 371/377 (98.4%). Of those with a cardiac anomaly and an abnormal axis (n = 18), five were felt to have an initial normal four-chamber view. An abnormal fetal cardiac axis, either larger or smaller than normal, is suggestive of a cardiac or intrathoracic anomaly and requires further investigation, such as fetal echocardiography. The cardiac axis should be considered with the four-chamber view in fetal ultrasound evaluation.

Objective To explore the normal reference range for fetal cardiac axis in the first trimester, and to evaluate its clinical value. Methods A total of 1639 unselected singleton pregnancies were enrolled from June 2017 to June 2018. Routine first trimester screening scan and fetal echocardiography were performed at 11+ 0~13+ 6 weeks of gestation. The cardiac axis was assessed by obtaining an axial view of the fetal chest at the level of the four-chamber view (when the atrioventricular valve was completely closed). Results The 1631 normal fetuses had a mean cardiac axis of (43.79±10.10)°, ranging from 10.80° to 74.02°. According to the gestational weeks, all pregnant women were divided into groups of 11+ 0~11+ 6 weeks, 12+ 0~12+ 6 weeks, and 13+ 0~13+ 6 weeks, and the mean fetal cardiac axis for them were (43.40±10.82)°, (43.91±9.88)°, and (43.65±9.96)°, respectively; the difference among the three groups was not statistically significant (F=0.40375, P>0.05). The normal cardiac axis reference range was defined as 95% of the range of the fetal cardiac axis (23.99~63.58°). Among the 1639 fetuses, 8 were diagnosed with congenital heart disease in the first trimester, 6 of whom had abnormal cardiac axis value (4 cases of left axis deviation, 1 case of right axis deviation, and 1 case of unmeasurableness). Conclusion The reference range of fetal cardiac axis in the first trimester may be helpful in improving the detection rate of congenital heart defects, and it can be used as one of the indicators for the diagnosis of congenital heart defects in the first trimester. Key words: Ultrasonography, Prenatal; Cardiac axis; Heart defects, Congenital; First trimester

To investigate whether fetal cardiac axis is affected by the presence of an abdominal wall defect (AWD) independent of congenital heart disease (CHD). Video ultrasound records from fetuses with AWDs identified from 1991-2004 were reviewed. Still images of the fetal cardiac four-chamber view were digitized and two independent examiners measured the cardiac axis. A cardiac axis of >65 degrees or <25 degrees was considered abnormal. Maternal charts were reviewed for fetal echocardiogram results and neonatal charts were reviewed for confirmation of CHD and type of AWD. Of 17 fetuses with omphalocele and 42 fetuses with gastroschisis, 16 (27%) fetuses had an abnormal cardiac axis, while only seven (12%) had CHD. Fifty-nine percent of fetuses with omphalocele had an abnormal cardiac axis and 35% had CHD. Fourteen percent of fetuses with gastroschisis had an abnormal cardiac axis and 2% had CHD. Of 43 fetuses with a normal cardiac axis, only one had CHD. Fetal cardiac axis is often affected by the presence of an AWD independent of CHD. A normal cardiac axis in fetuses with AWDs is an accurate predictor of the absence of CHD, the negative predictive value being 97.7%.

Fetal dedicated echocardiography is the standard to measure the fetal cardiac axis. However, fetal screening ultrasound (US) or fetal dedicated echocardiography may be technically limited. The purpose of this study was to explore the accuracy of fetal cardiac magnetic resonance imaging (MRI) to measure the cardiac axis in fetuses with congenital heart disease as an adjunct to fetal dedicated echocardiography and to assess the predictive value of fetal cardiac MRI measurements in distinguishing healthy fetuses from fetuses with congenital heart disease. This is a retrospective study of fetuses referred to our hospital for a fetal cardiac MRI from November 2019 to December 2021. Cardiac axes were measured in the 4-chamber view of the fetal heart using fetal cardiac MRI and dedicated echocardiography, or only using fetal cardiac MRI when screening US was technically limited. The fetuses were divided into a congenital heart disease group and a healthy control group. We used Bland-Altman analysis and the intraclass correlation coefficient (ICC) to assess the agreement of cardiac axis measurements in fetuses with congenital heart disease obtained by cardiac MRI and by fetal dedicated echocardiography. Receiver operating characteristic (ROC) curve analysis of the fetal cardiac axes in the congenital heart disease and healthy fetus groups assessed the predictive value of the cardiac axis measurements. This retrospective study included 431 women (162 carrying fetuses with congenital heart disease, 269 carrying healthy fetuses). Cardiac axes were measured in the 162 fetuses with congenital heart disease using fetal cardiac MRI and dedicated echocardiography. Cardiac axes were measured in the 269 healthy control fetuses using fetal cardiac MRI when fetal screening US was technically limited. The interobserver analysis and intraobserver analysis showed that the cardiac axis measured by fetal cardiac MRI and fetal dedicated echocardiography was repeatable (ICC>0.90). In 162 fetuses with congenital heart disease, Bland-Altman analysis showed a strong agreement between cardiac MRI and fetal dedicated echocardiography measurements for the cardiac axis. The ICC for the cardiac axis values between cardiac MRI and fetal dedicated echocardiography measurements was 0.99. In fetuses with congenital heart disease, 64.2% (104/162) had an abnormal cardiac axis. For the fetal cardiac axis in both the 162 fetuses with congenital heart disease and the 269 healthy fetuses, the area under the ROC curve reached 0.85 (95% confidence interval: 0.80-0.89; P<0.0001). The cardiac axis can be accurately measured using fetal cardiac MRI when fetal dedicated echocardiography/fetal screening US is technically limited. The cardiac axis measurements by fetal cardiac MRI are consistent with known cardiac axis measurements by fetal dedicated echocardiography. The frequency of abnormal cardiac axis depends on the type of congenital heart disease.

Objective To investigate the cardiac axis changes within the cardiac cycle of both normal fetuses and fetuses with congenital heart diseases (CHD), and construct reference range of cardiac axis for normal fetuses. Methods Two hundred sixty-five fetuses were enrolled in our study, of whom 197 were normal fetuses and 68 were fetuses with CHD. The cardiac axis was measured at end systole (CAS°) and at end diastole (CAD°) in each case. Subsequently, all parameters were compared between the normal and CHD groups. The independent t-test was used to compare CAS° and CAD° parameters between the healthy control group and the middle pregnancy group and the late pregnancy group, and between the healthy control group and the CHD group. According to the practice guideline the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG): the normal reference range for normal fetal cardiac axis was (45±20)°, with 65° defined as abnormal fetal cardiac axis. The Chi-square test was used to compare the proportion of CAS° and CAD° CA abnormalities between the healthy control group and the CHD group. Results No significant difference was observed in comparison of maternal age and gestational age between 197 healthy controls and 68 CHD controls (P>0.05). There was no significant difference between CAS° and CAD° of the fetus in the healthy control group with the increase of the second and third gestational weeks (P>0.05). The mean cardiac axis in control group was (40.88±10.27)° at end systole, and (35.07±9.44)° at end diastole, resulting in an average difference of (5.85±4.42)°. While the mean cardiac axis in fetuses with CHD was (44.34±15.03)° at end systole and (41.32±16.71)° at end diastole, resulting in an average difference of (5.01±3.52)°. Significant difference was observed between two groups (t=-2.11,-3.79, all P<0.05). Among 197 normal cases, there were 11 cases with abnormal CAS° (4 cases with decreased CAS° and 7 cases with increased CAS°) accounting for 5.6%. There were 27 cases with abnormal CAD° (26 cases with decreased CAD° and 1 case with increased CAD°), accounting for 13.7%. In 68 CHD cases, there were 10 cases with abnormal CAS° (4 cases with decreased CAS° and 6 cases with increased CAS°) accounting for 14.7%. There were 17 cases with abnormal CAD° (12 cases with decreased CAD° and 5 cases with increased CAD°) accounting for 25.0%. The abnormity rates of both CAS° and CAD° were significantly lower in normal group than in the CHD group. The difference was statistically significant (χ2=5.765, 4.657, all P<0.05). Conclusions Measurement of cardiac axis at end systole and at end diastole provides values in screening for fetuses with congenital heart disease, and can be used as a routine measurement tool. Key words: Heart disease; Fetus; Ultrasonography

To investigate changes in the cardiac axis (CAx) within the cardiac cycle of normal fetuses and fetuses with congenital heart defects (CHD). This was a retrospective case-control study in which stored videoclips of four-chamber views from 527 prenatal ultrasound examinations performed at 18 + 0 to 36 + 6 weeks of gestation were reviewed. Among the ultrasound scans included, 287 were of normal fetuses (controls) and 240 were of fetuses with CHD. In each case, the CAx was measured at end systole (just before the atrioventricular (AV) valve opened) and at end diastole (just before the AV valve closed). CAx measurements of fetuses with CHD were compared to those of controls. The mean CAx in the control group was 45.9 ± 8.5° at end systole and 38.3 ± 8.4° at end diastole (P < 0.001), resulting in an average difference of 7.6 ± 3.2°. The mean CAx in fetuses with CHD was 53.4 ± 17.8° at end systole and 47.5 ± 17.3° at end diastole (P < 0.001), resulting in an average difference of 5.9 ± 6.3°. However, in some forms of CHD, such as hypoplastic left heart syndrome and L-transposition of the great arteries, the CAx was greater at end diastole than at end systole, with a difference of more than 5°. In 21.3% of control fetuses, there was a CAx shift within the cardiac cycle of ≥ 10°. Abnormal CAx measured at end systole was strongly associated with CHD. Measurement of the CAx at end systole provides values that differ from those when measured at end diastole, in both normal fetuses and those with CHD. We recommend that the CAx be measured at end systole as a greater proportion of fetuses with CHD and fewer normal fetuses have an abnormal CAx at this stage compared to at end diastole. The occurrence of an abnormal CAx and the CAx shift within the fetal cardiac cycle depend on the type of CHD.

Cardiac heart defects affect nearly 6-12 per 1000 live births in the general population and are more frequent than common trisomies. To assess the efficacy and technical limitations of first-trimester fetal heart evaluation in the 11-14th-weeks' scan and comparison with the second-trimester anatomical exam by ultrasound. Between April 2015 and July 2020, medical records and ultrasound data of 3295 pregnancies who underwent first-trimester fetal anatomy exams by ultrasound were reviewed retrospectively. All ultrasound exams were performed by the same two operators (TUKD, OP) with transabdominal transducers. Fetal situs, four-chamber view, outflow tracts, and three-vessel trachea view are the cornerstones of first-trimester fetal heart examination. Conventional grayscale mode and high-definition power Doppler mode were utilized. The same operators re-examined all cases between the 18 and 23 weeks of gestation by ISUOG guidelines. We performed a combined transvaginal and transabdominal approach for only 101 cases (3.06%). The mean maternal age was 31.28 ± 4.43, the median gestational age at the first-trimester ultrasound exam was 12.4 weeks, and the median CRL was 61.87 mm (range was 45.1-84 mm). Even combined approach situs, cardiac axis, and four-chamber view could not be visualized optimally in 28 cases (0.7%). Outflow tracts were visualized separately in 80% (2636 in 3295) cases. Three vessel-trachea views were obtained in 85.4% (2814 in 3295) cases by high-definition Doppler mode. There were 47 fetuses with cardiac defects in 3295 pregnancies with the known pregnancy outcome. Ten cases had abnormal karyotype results. Thirty-two fetuses with cardiac anomalies (9.7 in 1000 pregnancies) were detected in the first-trimester examination, and the remaining 15 (4.55 in 1000 pregnancies) cases were diagnosed in the second-trimester examination. The prevalence of congenital cardiac anomalies was 14.25 in 1000 pregnancies. Fifteen cases were missed in the first-trimester exam. Also, ten fetuses which had abnormal cardiac findings in the first-trimester exam were not confirmed in the second-trimester exam. Sensitivity, specificity, positive, and negative predictive values were calculated as 65.3%, 99.7%, 66.8%, and 99.67%, respectively. Late first-trimester examination of the fetus is feasible and allows earlier detection of many structural abnormalities of the fetus, including congenital heart defects. Suspicious and isolated cardiac abnormal findings should be re-examined and confirmed in the second-trimester exam. Previous abdominal surgery, high BMI, and subtle cardiac defects can cause missed cardiac abnormalities.

BackgroundCongenital heart disease (CHD) is the most common form of congenital anomalyand is a leading cause of neonatal morbidity and mortality. Major congenital heart disease (CHD) is defined as any...

Ultrasonographic left cardiac axis deviation: A marker for fetal anomalies

Purpose The purpose of this study was to assess the cardiac axis in fetuses with conotruncal anomalies during four-chamber view scanning. Materials and Methods We retrospectively evaluated the cardiac axis of 150 fetuses with conotruncal anomalies within the second and third trimester between October 2008 and August 2014. The cardiac axis was obtained by the angle of two lines in a transverse view of the fetal thorax at the level of the four-chamber view. The first line divided the thorax into two equal halves starting from the spine posteriorly ending at the sternum. The second line was placed through the interventricular septum of the fetal heart. The angle was calculated using OsiriX software. Results 23 had double outlet right ventricle (DORV), 17 had truncus arteriosus communis (TAC), 36 had tetralogy of Fallot (TOF), and 74 had complete transposition of the great arteries (d-TGA). In fetuses with DORV ≤ 24 + 6 weeks ofgestation (wks), the mean cardiac axis was 52.5° (p = 0.005), at ≥ 25 + 0 wks it was 51.1° (p = 0.0003). In fetuses with TAC ≤ 24 + 6 wks, the mean cardiac axis was 56.8° (p = 0.01), at ≥ 25 + 0 wks it was 50.0° (p = 0.05). In fetuses with TOF ≤ 24 + 6 wks, the mean cardiac axis was 67.5° (p < 0.0001), at ≥ 25 + 0 wks it was 63.8° (p < 0.0001). In fetuses with d-TGA ≤ 24 + 6 wks, the mean cardiac axis was 45.6°, at ≥ 25 + 0 wks it was 45.4° (not significant). Throughout gestation, the cardiac axis did not show a difference in the two separate examinations. Conclusion In fetuses with DORV, TAC and TOF, the cardiac axis is significantly different from the normal axis, but in fetuses with TGA there is no significant difference compared to the normal axis. Therefore, analysis of the heart axis could be useful for screening for conotruncal anomalies.

In 2006 the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) published practice guidelines for the sonographic screening of congenital heart disease (CHD) during the second trimester of pregnancy1. This document described two levels for screening low-risk fetuses for heart anomalies. Firstly, a ‘basic’ scan should be performed by analyzing a four-chamber view of the fetal heart. Secondly, an ‘extended-basic’ scan further examines the size and relationships of both arterial outflow tracts. The term ‘fetal echocardiogram’ was also mentioned as a more detailed sonographic evaluation to be performed by specialists in the prenatal diagnosis of CHD. Although common indications and imaging techniques were briefly discussed, it was thought important to further explain how this advanced diagnostic procedure differs from the basic and extended-basic cardiac screening examinations. A Fetal Echocardiography Task Force was subsequently asked to develop a standard description of ‘what constitutes a fetal echocardiogram’. Our original goal was to develop guidelines for a detailed examination of the fetal heart that were based on the literature and a consensus opinion of an expert panel. However, we soon realized that this project was quite different from developing minimum practice guidelines for fetal cardiac screening. There are several imaging modalities that can be used to evaluate fetal heart anomalies, ranging from M-mode techniques and color Doppler sonography to the use of four-dimensional (4D) ultrasonography with spatiotemporal image correlation (STIC). Consequently, our original efforts to develop a minimum practice guideline for fetal echocardiography evolved into a consensus statement that covers the following topics:

First-trimester fetal heart evaluation: time to move forward.

Objective To assess prenatal heart disease screening program by ultrasound. Methods A total of 11 544 second-trimester screening scans were performed before 24 weeks′ gestation on 11 410 women between February 2004 and May 2007 in Obstetrics and Gynecology Hospital of Fudan University. Fetal heart screening was based on four-chamber and outflow tract views( left ventricular outflow + three vessel view). The sensitivity and specificity of different views were evaluated. Follow-up data of newborns was obstained. Results (1) Among 11 544 cases, 48 cases of congenital heart disease (CHD) were diagnosed in utero. Six cases were false negative, and 2 cases were false positive. The incidence of CHD was 0.47% (54/11 544). (2) Thirty-three CHDs were detected based on the four-chamber view, including 18 ventricular septal defect (9 with conotroncal anomalies),6 anomalous atrioventricle valve, 9 disproportion of left/right ventricle. The sensitivity of the four-chamber view alone was 61.11% (33/54), and the specificity was 99. 98% ( 11 488/11 490). Fifteen CHDs were detected based on the left ventricular outflow and three vessel views, including 1 pulmonary atresia, 3 pulmonary valve stenosis, 2 transposition of the great arteries ( TGA ), 1 pulmonary stanosis with TGA, 6 tetralogy of Fallot, and 2 pulmonary stenosis. The sensitivity of the combination of the four-chamber and outflow tract views was 88. 89% (48/54), and the specificity was 99. 98% (11 488/11 490). (3)Of 48 CHDs,11 cases were eceompanied by other malformations. Eleven cases were performed amniocentesis, amony whom 5 cases were trisemy 21. Conclusion The screening program based on four-chamber and outflow tract views shows good sensitivity and excellent specificity. Our prenatal heart screening program is clinically feasible. Key words: Heart defects,congenital; Echocardiography ; Ultrasonography, prenatal