Qualitative real-time cross-sectional echocardiographic imaging of the human fetus during the second half of pregnancy

SKGC: A General Semantic-Level Knowledge Guided Classification Framework for Fetal Congenital Heart Disease

Congenital heart disease (CHD) is the most common congenital disability affecting healthy development and growth, even resulting in pregnancy termination or fetal death. Recently, deep learning techniques have made remarkable progress to assist in diagnosing CHD. One very popular method is directly classifying fetal ultrasound images, recognized as abnormal and normal, which tends to focus more on global features and neglects semantic knowledge of anatomical structures. The other approach is segmentation-based diagnosis, which requires a large number of pixel-level annotation masks for training. However, the detailed pixel-level segmentation annotation is costly or even unavailable. Based on the above analysis, we propose SKGC, a universal framework to identify normal or abnormal four-chamber heart (4CH) images, guided by a few annotation masks, while improving accuracy remarkably. SKGC consists of a semantic-level knowledge extraction module (SKEM), a multi-knowledge fusion module (MFM), and a classification module (CM). SKEM is responsible for obtaining high-level semantic knowledge, serving as an abstract representation of the anatomical structures that obstetricians focus on. MFM is a lightweight but efficient module that fuses semantic-level knowledge with the original specific knowledge in ultrasound images. CM classifies the fused knowledge and can be replaced by any advanced classifier. Moreover, we design a new loss function that enhances the constraint between the foreground and background predictions, improving the quality of the semantic-level knowledge. Experimental results on the collected real-world NA-4CH and the publicly FEST datasets show that SKGC achieves impressive performance with the best accuracy of 99.68% and 95.40%, respectively. Notably, the accuracy improves from 74.68% to 88.14% using only 10 labeled masks.

Prenatal diagnosis of congenital heart defects: echocardiography

Congenital heart defects (CHD) are the most common congenital anomaly, and the majority can be diagnosed during prenatal life. Prenatal detection rates remain highly variable, as most CHD occur in low risk pregnancies and therefore depend on the maternal obstetric provider to recognize fetal cardiac abnormality on obstetric screening anatomic ultrasound. Fetuses with abnormal findings on obstetric screening anatomic ultrasound and/or risk factors for cardiac disease should be referred for evaluation with fetal echocardiography. Fetal echocardiography should be performed by specialized sonographers and interpreted by physicians with knowledge of evolving fetal cardiac anatomy and physiology throughout gestation. A fetal echocardiography examination, which can be done from the late first trimester onward, utilizes a standardized and systemic approach to diagnose fetuses with CHD or other forms of primary or secondary cardiac disease. The field of fetal cardiology has advanced past the accurate prenatal diagnosis of simple and complex CHD, as fetal echocardiography enables understanding of dynamic fetal cardiac physiology and consideration of potential fetal/neonatal treatment. The greatest impact of fetal echocardiography remains identification of critical CHD before birth to allow immediate cardiac management after delivery to decrease neonatal morbidity and mortality. Analyzing the severity of abnormal cardiac physiology in various forms of CHD before birth allows the fetal cardiologist to prognosticate effects on the developing fetus, predict risk of postnatal hemodynamic instability, guide delivery planning through multidisciplinary collaboration, and anticipate how the disease will impact the neonate after delivery.

Prenatal cardiac care: Goals, priorities & gaps in knowledge in fetal cardiovascular disease: Perspectives of the Fetal Heart Society

Perinatal cardiovascular care has evolved considerably to become its own multidisciplinary field of care. Despite advancements, there remain significant gaps in providing optimal care for the fetus, child, mother, and family. Continued advancement in detection and diagnosis, perinatal care and delivery planning, and prediction and improvement of morbidity and mortality for fetuses affected by cardiac conditions such as heart defects or functional or rhythm disturbances requires collaboration between the multiple types of specialists and providers. The Fetal Heart Society was created to formalize and support collaboration between individuals, stakeholders, and institutions. This article summarizes the challenges faced to create the infrastructure for advancement of the field and the measures the FHS is undertaking to overcome the barriers to support progress in the field of perinatal cardiac care.

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Progress in perinatal cardiology is challenged by the rarity of fetal cardiac disease, care variation, and barriers to collaboration.

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The Fetal Heart Society was founded to formalize collaboration between the multiple disciplines in perinatal cardiac care.

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The FHS facilitates interdisciplinary multicenter research, education and advocacy to provide optimal perinatal cardiac care.

Mortality burden in patients born with Ebstein’s anomaly: a 40-year nationwide cohort study

Aims 

Survival rates for unoperated patients with Ebstein’s anomaly (EA) are unknown. We estimated overall long-term mortality in operated and unoperated EA patients, compared with the general population in Sweden.

Methods and results 

Using national medical registries, Swedish individuals born 1970–93 and diagnosed with EA between 1970 and 2011 were included. The hazard ratio for overall mortality for EA patients (n = 216) vs. the matched comparison cohort (n = 2160) was 43.7 [95% confidence interval (CI): 24.8–82.5]. Mortality risk for EA patients (vs. controls) decreased as birth period progressed, with hazard ratios declining from 63.6 (95% CI: 26.3–191.8) for those born in the 1970s to 34.4 (95% CI: 15.8–83.1) for those born in the 1980s and 20.2 (95% CI: 1.6–632.5) for those born at the beginning of 1990s. The overall mortality hazard ratios for unoperated and operated patients with EA (vs. controls) were 30.2 (95% CI: 13.8–73.3) and 63.7 (95% CI: 28.1–172.5), respectively. The risk of mortality among unoperated EA patients (vs. controls) declined with progressing birth period, with hazard ratios declining from 58.4 (95% CI: 15.1–415.2) in the 1970s to 22.9 (95% CI: 8.0–75.3) in the 1980s and 10.2 (95% CI: 0.3–395.9) in the 1990s.

Conclusion 

Overall all-cause mortality for patients with EA declined dramatically from 64 times to 20 times that of controls without EA, from the 1970s to the early 1990s. Unoperated patients with EA had better survival than did operated patients, possibly reflecting the higher severity of disease or more severe associated cardiac defects in patients undergoing surgery.

A Generic Quality Control Framework for Fetal Ultrasound Cardiac Four-Chamber Planes

Quality control/assessment of ultrasound (US) images is an essential step in clinical diagnosis. This process is usually done manually, suffering from some drawbacks, such as dependence on operator's experience and extensive labors, as well as high inter- and intra-observer variation. Automatic quality assessment of US images is therefore highly desirable. Fetal US cardiac four-chamber plane (CFP) is one of the most commonly used cardiac views, which was used in the diagnosis of heart anomalies in the early 1980s. In this paper, we propose a generic deep learning framework for automatic quality control of fetal US CFPs. The proposed framework consists of three networks: (1) a basic CNN (B-CNN), roughly classifying four-chamber views from the raw data; (2) a deeper CNN (D-CNN), determining the gain and zoom of the target images in a multi-task learning manner; and (3) the aggregated residual visual block net (ARVBNet), detecting the key anatomical structures on a plane. Based on the output of the three networks, overall quantitative score of each CFP is obtained, so as to achieve fully automatic quality control. Experiments on a fetal US dataset demonstrated our proposed method achieved a highest mean average precision (mAP) of 93.52% at a fast speed of 101 frames per second (FPS). In order to demonstrate the adaptability and generalization capacity, the proposed detection network (i.e., ARVBNet) has also been validated on the PASCAL VOC dataset, obtaining a highest mAP of 81.2% when input size is approximately 300 × 300.

Comparison of echocardiographic findings in fetuses at less than 15 weeks' gestation with later cardiac evaluation

OBJECTIVE

To compare the echocardiographic findings in fetuses at < 15 weeks' gestation with a later follow-up scan, and determine both the accuracy of early diagnosis and the frequency of findings that change between scans.

METHODS

For the period 2002 to the end of 2009, we searched our database for all patients who had had a detailed fetal echocardiogram at less than 15 completed weeks' gestation and a repeat scan at least 6 weeks later.

RESULTS

Of 1200 patients fulfilling our selection criteria, the cardiac findings were normal at both scans in 1069. In 46 cases the same cardiac abnormality was seen at both scans. There was a false-positive diagnosis at early scan in seven cases. In 50 cases, there were mildly abnormal functional findings early in pregnancy with no abnormality found later. In 29 fetuses, there was discordance between the early and later morphological diagnosis, 15/29 being considered significant differences, with 10/15 representing true progression of findings between the early and later scans, rather than missed or incorrect diagnoses.

CONCLUSIONS

A high degree of accuracy in the identification of congenital heart disease can be achieved by early fetal echocardiography (sensitivity 84.8 (95% CI, 75.0-91.9)%, specificity 95.3 (95% CI, 93.9-96.4)%), although the identification of every case of tetralogy of Fallot and small atrioventricular septal defects presents particular diagnostic challenges at this gestational age. A small but significant group showed progression of findings during this stage of rapid fetal heart growth, particularly in obstructive lesions.

Fetal diagnosis and imaging in cardiology

BACKGROUND

Fetal echocardiography plays a critical role in the diagnosis and management of structural, functional and rhythm-related fetal cardiovascular disease.

OBJECTIVES/METHODS

This article reviews the history of fetal echocardiography and the prenatal diagnosis of fetal cardiovascular disease as well as the evolution of the field of fetal cardiology. The clinical application of fetal echocardiography, including indications for referral, timing of referral and considerations in the diagnosis and serial assessment of fetal cardiovascular disease, is presented.

CONCLUSIONS

Newer directions in the field of fetal cardiology, including first trimester diagnoses and fetal intervention, will continue to expand its role in the evaluation and treatment of affected pregnancies in the future; however, equally as important are efforts to continue to improve prenatal detection rates.

The antenatal detection rate of major congenital heart disease in Scotland

Ultrasonography has been used to detect fetal congenital heart disease since the 1980s, although there has been little uniformity in policy. In the UK, data published for 1993-1995 found an average detection rate of 23.4% with a Scottish rate of 9.6%. At the time of this study, 10 out of the 14 health boards in Scotland were implementing the 16-22-week fetal anomaly scan (FAS). The aims of this study were to determine the rate of antenatal diagnosis of major congenital heart disease (MCHD) throughout Scotland during 1 January to 31 December 2006, to document the regional differences in detection and to determine if implementation of a FAS significantly improved rates. Retrospective data were collected from the centralized Paediatric Cardiac Services in Edinburgh and Glasgow. The database contains information on all infants with cardiac disease in Scotland. All infants requiring cardiac intervention or dying in the first year of life were included. The results showed that the antenatal diagnosis rate for Scotland was 28% (95% CI 21.2%, 34.9%). The Scottish health boards that had implemented the FAS had a significantly higher antenatal detection rate (χ2 test P = 0.037). In conclusion, antenatal detection rate of MCHD varies widely throughout Scotland. Implementation of the FAS has made a significant difference to antenatal diagnosis

Morphometric study of the ventricular segment of the human fetal heart between 13 and 20 weeks' gestation

Our objective was to determine the normal dimensions of the ventricular segment of the human fetal heart between 13 and 20 weeks' gestation.

STUDY DESIGN

103 hearts obtained by necropsy were dissected and measurements of different portions of ventricles were determined under stereoscopic magnification. In each ventricle were measured anteroposterior and lateral diameters, inlet and outlet length, and thickness of walls at different levels. Our results showed the cardiac apex was constituted by the left ventricle in 68.9% of the hearts. Both ventricles showed linear growth during this period of fetal development. Ranges in median values of external and internal ventricular measurements were determined. The left ventricular wall was thicker than the right, and the right ventricular cavity was larger. This study provides morphometric reference information concerning the dimensions and growth of both ventricles of the fetal heart, which may be useful in pediatric cardiac surgery and echocardiography.

A review of findings in fetal cardiac section drawings, part 1: The 4-chamber view

OBJECTIVES

The goal of this presentation is to review some of the common and rare fetal heart abnormalities and to provide an easy approach to these findings with schematic drawings.

METHODS

Over the past 10 years, we collected cases in which the common views of the heart were abnormal and the differential diagnoses that existed for each. The presentation shows the normal sonographic sections and then variations of these sections and the associated anomalies. We used illustrative drawings to present these findings, enabling us to point out the main sonographic features of abnormalities of the heart.

RESULTS

The work reviews 17 fetal heart abnormalities in schematic drawings.

CONCLUSIONS

This short review highlights several of the anomalies that can be recognized on the common sonographic views. The drawings tend to simplify the findings but serve as a basis for those doing fetal echocardiography when they encounter an unusual finding.

Three-Dimensional Echocardiography for Studies of the Fetal Heart: Present Status and Future Perspectives

Three-dimensional (3D) ultrasound of the fetal heart is increasingly being used in prenatal diagnosis. While very detailed fetal cardiac studies can be performed using the various 3D ultrasound modalities, their utility for screening for fetal heart disease is yet to be proven. With the emergence of even newer technologies such as quantification techniques and two-dimensional matrix arrays, further improvements are imminent.

Assessing fetal cardiac ventricular function

Fetal echocardiography has been used primarily to identify fetuses with structural malformations of the heart. Evaluation of fetal ventricular function, however, has received minimal attention since the inception of fetal echocardiography in the early 1980s. This communication reviews the use of M-mode, B-mode and pulsed Doppler ultrasound to examine cardiac function. M-mode ultrasound is used to determine the size of the fetal heart, the end-diastolic and end-systolic dimensions of the ventricular chambers, and the thickness of the ventricular walls and the interventricular septum, and to measure the diameter of the mitral and tricuspid valves as well as the diameter of the aorta and pulmonary artery. B-mode evaluation of the fetal heart includes measurement of atrial and ventricular dimensions as well as dimensions of the outflow tracts. This modality is useful when M-mode measurements cannot be made due to fetal position. Once measurements of cardiac structures are obtained using either M-mode or B-mode ultrasound, pulsed Doppler recording of mitral valve, tricuspid valve, aortic valve and pulmonary artery waveforms can be used to compute cardiac output as well as stroke volume. In addition, pulsed Doppler can be used to evaluate diastolic and systolic cardiac functions by examining the components of each waveform.

Morphometric study of the human fetal heart I. Arterial segment

This study measured the dimensions of the great arteries of normal human fetal hearts at an early fetal stage (between 13-20 weeks post-fertilization) in 103 fetuses obtained by necropsy. Different segments of the aorta and the pulmonary artery were dissected and their external diameters measured under stereoscopic magnification. All segments showed linear growth during this period of fetal development. Ranges in median values of external diameters associated with the pulmonary artery were: 2.1-4.2 mm for the valve ring; 2.2-4.2 mm for the main pulmonary trunk; 1.2-2.5 mm for the right pulmonary artery; 0.9-2.18 mm for the left pulmonary artery; and 4.0-8.0 mm for the length of the main pulmonary trunk. Similarly, in the aorta, median diameters were: 2.1-4.2 mm for the ascending aorta; 1.92-3.8 mm for the aortic arch; 1.45-3.0 mm for the aortic isthmus; and 1.75 -3.35 mm for the descending aorta. The diameter of the ductus arteriosus ranged between 1.2-2.45 mm. The growth rates of the pulmonary artery and the aorta were similar. The diameter of the ascending aorta was found to be greater than that of the descending aorta and the right pulmonary artery was wider than the left pulmonary artery. In addition, the magnitude of growth in the various aortic segments was different and the ratios obtained between the aortic isthmus and the ascending and descending aortae, ranged between 0.66-0.93. This study provides important morphometric reference information concerning the dimensions and growth of the great arteries of the fetal heart and has clinical application in pediatric cardiac surgery and echocardiography.

Technique of fetal echocardiography

The fetal heart is examined by a series of sequential ultrasound views, which image the cardiac connections and intracardiac structure. The imformation obtained by cross-sectional imaging can be augmented by the use of cardiac measurements, and evaluation with pulsed or color flow Doppler. A thorough familiarity with the normal appearance and systematic evaluation of standard views can exclude or diagnose major heart malformations. With training, cardiac evaluation can be performed during routine obstetric scanning, in a matter of minutes. An accurate description of any abnormal findings and a knowledge of the types of cardiac malformation which are possible, will help the examiner to reach a correct diagnosis.

Factors influencing the prenatal detection of structural congenital heart diseases

OBJECTIVE

To assess the factors influencing the prenatal detection rate of structural congenital heart diseases (CHDs).

METHODS

A retrospective study was conducted at a major obstetric hospital in Australia between 1 January 1996 and 30 June 1999. The medical records of all fetuses and infants born with CHD, except those with isolated patent ductus arteriosus or secundum atrial septal defect, were reviewed. Only pregnancies that had prenatal ultrasound scan assessments for morphological surveys were included. The following factors that may influence the detection rate were assessed: complexity of the lesions; experience of the sonographers (performance in tertiary versus non-tertiary institutions); presence of other structural or chromosomal anomalies; and maternal body mass index (BMI).

RESULTS

The incidence of structural CHD in this series, excluding cases referred from other hospitals, was 7.0 per 1000 (179/25 529). Of the 179 pregnancies with CHD, 151 had prenatal ultrasound scans and were included in the study. The overall detection rate for CHDs in this series was 40.4%. The detection rate for isolated septal defects was poor (13.7%). The detection rates were significantly higher for complex lesions (54%), for lesions with concomitant septal defects (66.7%), and for lesions with abnormal four-chamber views (62.9%). The detection rate was also higher if the scan was performed in the tertiary institution, and if there were other chromosomal or structural anomalies. Maternal BMI did not affect the detection rate in the current series. Stepwise logistic regression analysis showed that three independent variables affecting the detection rate were complexity of the cardiac lesion, experience of the operator, and the detection of chromosomal anomalies.

CONCLUSION

A high detection rate for major CHDs can be achieved in a screening setting but there is still room for improvement in scanning skills in the four-chamber view and great-artery analysis in both tertiary and local centers.

Real-time three-dimensional fetal echocardiography--optimal imaging windows

A total of 15 fetuses were scanned using 2-D array volumetric ultrasound (US). Acquired cardiac data were converted for rendering dynamic 3-D surface views and reformatting cross-sectional views. The image usefulness was compared between the data obtained from subcostal/subxiphoid and other imaging windows; the former are usually free of acoustic shadowing. Of 60 data sets recorded, 12 (20%) were acquired through subcostal windows in 6 (40%) patients. Subcostal windows were unavailable from the remaining patients due to unfavourable fetal positions. Of the 12 sets, 6 (50%) provided the dynamic 3-D and/or cross-sectional views of either the entire fetal heart or a great portion of it for sufficient assessments of its major structures and their spatial relationships. Of 48 data sets from other windows, only 9 (19%) provided such 3-D and/or cross-sectional views; the lower rate being due to acoustic shadowing. Real-time 3-D US is a convenient method for volumetric data acquisition. Through subcostal windows, useful information about the spatial relationships between major cardiac structures can be acquired. However, to offer detailed information, considerable improvement in imaging quality is needed.

Fetal cardiology

A systematic approach to examination of the fetal heart will enhance the detection of structural cardiac abnormalities and will enable an accurate diagnosis of congenital heart disease to be made. Once an abnormality has been detected appropriate counselling must be provided and adequate support given to the parents. Associated extracardiac abnormalities should be sought for, and plans for the remainder of pregnancy, delivery and postnatal management should be made using a team approach. In cases resulting in termination of pregnancy, permission for autopsy should be sought to confirm the ultrasound diagnosis. Although in-utero therapy is available for some forms of fetal arrhythmia and a few limited cases of structural heart disease, this should be conducted in tertiary centres.

In situ morphometric analysis of left and right ventricles in fetal rats: changes in ventricular volume, mass, wall thickness, and valvular size

We studied morphological changes in the left and right ventricles of fetal rats in late-gestation using rapid whole-body freezing technique. Pregnant Wistar rats (term, 21.5 day) were immediately frozen in liquid nitrogen on 17-, 18-, 19-, 20-, and 21-day of gestation. The frozen fetal hearts were serially sectioned with a sliding microtome and photographed. The ventricular volume, mass, wall thickness, and area of valvular orifice were measured on the photographs. During the study period, the left and right ventricular volumes increased very rapidly (9.9-fold and 7.6-fold, respectively) compared with the increase in the body weight (4.0-fold); the volumes divided by body weight increased linearly. Left and right ventricular masses also rapidly increased (5.9-fold and 5.0-fold, respectively). Mass/volume ratios for the two ventricles rapidly decreased. The wall thicknesses divided by body weights rapidly decreased with the progression of the gestational age. The left and right ventricles at 17 day of gestation have relative hypertrophy and relatively large valvular orifices as compared with those in terminal gestation. The improvement of the relative hypertrophy of the ventricles may indicate the morphological and functional maturation of the fetal heart.

Current and potential impact of fetal diagnosis on prevalence and spectrum of serious congenital heart disease at term in the UK. British Paediatric Cardiac Association

BACKGROUND

Assessment of the effect of fetal diagnosis on the prevalence of congenital heart disease at term requires national ascertainment because referral patterns are not rigorously structured.

METHODS

Between 1993 and 1995, all 17 paediatric cardiac centres in the UK submitted to a database lists of all fetuses diagnosed, and all infants needing surgery or interventional catheterisation or dying in the first year of life because of structural heart disease; details included the postal area of residence.

FINDINGS

There were 4799 affected pregnancies, 4165 babies born alive, 1124 fetal diagnoses, and 567 terminations of pregnancy because the fetus had structural heart disease. Thus, a fetal diagnosis was made in 23.4% of affected pregnancies (11.7% of all affected livebirths) with geographical variability in diagnostic rates.

INTERPRETATION

Fetal cardiac screening has an effect on the prevalence and types of congenital heart disease seen at term because many affected pregnancies are terminated. If detection rates of affected fetuses rose nationally to those seen in the 15 postal areas where detection rates were significantly higher than the national average in 1993-95, we would expect about 218 fewer affected individuals to be born annually.

The fetal heart: a practical sonographic approach

Structural abnormalities of the heart are a fairly common problem, affecting more than 8 of 1,000 newborns annually in the United States. Therefore, sonographic detection of these anomalies in utero is important. It is possible to detect a high percentage of fetal cardiac anomalies through proper sonographic examination using three central views of the heart: (1) the four-chamber view; (2) the aortic outflow tract view; and (3) the pulmonary output tract view. Although average sonologists may not be able to provide a precise diagnosis for a cardiac abnormality, they are able to recognize such abnormalities in a high percentage of cases by using these three views and by answering the following questions: (1) Is the heart in a normal position? (2) Is the heart size normal? (3) Are the ventricles equal in size? (4) Is there a septal defect? (5) Are the atrioventricular valves in a normal position? and (6) Is there any abnormality of the endocardium, myocardium, or pericardium? This article presents a practical approach to the detection of fetal cardiac anomalies using the four-chamber and outflow tract views. Examples of normal anatomy and cardiac pathology are provided as well as a listing of differential diagnoses that should be reviewed when certain abnormalities are visualized.

Fetal echocardiography in detecting anomalous pulmonary venous connection: four false positive cases

Prenatal detection of congenital heart disease is possible from the 16th week of pregnancy, the ideal time being the mid-trimester, when most cardiac abnormalities can be detected. However, identification of anomalous pulmonary venous connection is difficult before birth and the sensitivity of fetal echocardiography in detecting this anomaly is low. Four cases are reported in which fetal echocardiographic findings obtained during the third trimester of pregnancy were highly suggestive of anomalous pulmonary venous connection. Right ventricular and atrial dominance associated with an enlarged coronary sinus or dilated superior vena cava were identified and considered to be indirect markers of the anomaly. No other cardiac anomaly was detectable. In all cases right ventricular and atrial dominance with dilated coronary sinus or superior vena cava were confirmed after birth despite the presence of normal pulmonary venous connections. These results confirm that the prenatal detection of this condition is difficult and should be based on the direct visualisation of anomalous pulmonary venous connections. The sole detection of indirect signs, such as right atrial and ventricular dominance with or without a dilated coronary sinus, superior vena cava, or inferior vena cava, does not warrant the diagnosis of anomalous pulmonary venous connection. Since the pulmonary venous flow in the human fetus is not as small as is commonly assumed, an anomalous drainage should be detectable when present and therefore should be specifically sought if the anomaly is suspected. The reasons for the presence of such transient cardiac anomalies remain obscure, but they might be related to functional or morphological rearrangement of the heart during fetal and perinatal life.

Chronic alterations in cardiac mechanics after fetal closed heart operation

Pulmonary artery banding was performed in 8 fetal sheep at 125 days' gestation to evaluate the feasibility of fetal closed cardiac operation. At 135 days' gestation, the fetuses were delivered and the cardiac mechanics were evaluated using a modified Langendorff isolated heart preparation. Two of the 8 fetuses aborted spontaneously 2 and 7 days after operation. Six fetuses (75%) survived the 10 days after delivery. The left ventricular cardiac mechanics in the banded fetuses (group I) were compared with those in 8 control fetuses (group II). All fetal hearts in both groups displayed a significant volume-pressure relationship. The volume-pressure curve was found to be shifted upward and to the left in the fetal hearts after pulmonary artery banding. The left ventricles subjected to increased in utero preload secondary to pulmonary artery banding were capable of generating greater peak systolic and developed pressures. Because the fetal heart manifests a Starling type of preload reserve, as such, it demonstrates that the possibility exists for subsequent fetal development to be altered by intrauterine intervention.

Prospective diagnosis of 1,006 consecutive cases of congenital heart disease in the fetus

OBJECTIVE

This report describes our experience with fetal congenital heart disease since 1980.

BACKGROUND

Knowledge and expertise in the diagnosis, management and natural history of fetal congenital heart disease is increasingly demanded by both obstetricians and parents. The analysis of a large series should help the pediatric cardiologist to provide this service.

METHODS

The notes of 1,006 patients, where a prospective diagnosis of fetal congenital heart disease was made, were reviewed. The reason for referral, the diagnosis made, the accuracy of diagnosis, the fetal karyotype and the outcome of the pregnancy were noted. The cases were grouped into malformation categories, and the spectrum of disease seen was compared with that found in infants.

RESULTS

Most fetal cardiac anomalies are now suspected by the ultrasonographer during obstetric scanning. A different incidence of abnormalities is seen compared with that expected in infants. Chromosomal anomalies were more frequent in the fetus than in live births. The accuracy of diagnosis was good. The survival rate after diagnosis was poor because of frequent parental choice to interrupt pregnancy and the complexity of disease.

CONCLUSIONS

A large experience with fetal congenital heart disease allows the spectrum of disease to be described with accuracy and compared with that in infancy. Knowledge of the natural history of heart malformations when they present in the fetus allows accurate counseling to be offered to the parents. If the trend in parental decisions found in this series continues, a smaller number of infants and children with complex cardiac lesions will present in postnatal life.

Pressure-volume relationship of the fetal lamb heart

In contrast to the adult heart, the fetal heart reportedly has little functional reserve. With increased clinical emphasis on fetal cardiac diagnosis, neonatal surgery, and the potential for future fetal cardiac intervention, it is essential that we better understand fetal cardiac function. Therefore, to demonstrate the extent of fetal cardiac preload reserve, we studied 10 fetal lambs using an isolated, isovolumic, blood-perfused heart preparation. We maintained constant afterload, inotropic state, coronary blood flow, heart rate, and perfusate blood gas values. As left ventricular (LV) volume (preload) was incrementally increased, LV end-diastolic pressure and LV peak systolic pressure were recorded. Linear regression analysis demonstrated that increases in LV developed pressures were predicted by the LV volume, demonstrating the presence of the Frank-Starling mechanism in each case. The plateau of the Starling pressure-volume curve occurred at an LV end-diastolic pressure of 12.5 +/- 4.79 mm Hg (95% confidence interval, 9.07 to 15.9 mm Hg), lower than the plateau expected in the adult heart. This implies that, in the management of fetal and immature neonatal hearts, preload reserve plays an important but limited role in cardiac reserve.

Use of casts in the necropsy diagnosis of fetal congenital heart disease

OBJECTIVE

To evaluate a casting technique in the interpretation of fetal cardiac anatomy.

DESIGN

In 32 fetuses, the echocardiographic and cast features were compared and correlated.

PATIENTS

Three normal fetal heart specimens from spontaneous abortuses and 32 specimens from spontaneous or induced abortions with congenital heart malformation.

RESULTS

There was close correlation between the echocardiographic and anatomical features in 32 abnormal fetuses studied. In some, additional features of diagnosis could be displayed on the cast and the relative sizes of the cardiac structures could be appreciated and defined.

CONCLUSIONS

With increasing echocardiographic detection of congenital heart disease in early prenatal life, an increasing number of fetal heart specimens of small size are dissected for pathological confirmation. The use of silicone rubber casts to reproduce the internal anatomy proved a useful addition to dissection, providing a three dimensional model of the cardiac defect.

Fetal echocardiography in the assessment of lupus pregnancies

Fetal echocardiography is the most sensitive tool in detecting the earliest possible changes of the cardiovascular system related to maternal lupus. The institution of aggressive therapy at that time may still be able to reverse the process before permanent fetal cardiac injury occurs. Experience with this technique is described.

Ebstein anomaly: report of a familial occurrence and prenatal diagnosis

The Ebstein anomaly is a rare congenital heart disease involving the position and structure of the tricuspid valve. Although most cases are sporadic, familial occurrence has been documented. We report on 2 sisters, born to consanguineous parents, who were diagnosed prenatally with severe Ebstein anomaly.

Normal fetal foramen flap and transatrial Doppler velocity pattern

To define the normal size of the foramen ovale and the transatrial Doppler velocity pattern in the fetus, we examined foramen ovale size, foramen flap angle, and motion in 48 consecutive normal human fetal ultrasound studies. The maximal foramen diameter was similar in size to aortic root diameter at all gestational ages, differing by no more than 1.0 mm in any study. Attachment angle at the junction of the foramen with the rim of the foramen varied from 30 degrees to 50 degrees; at least a 30-degree angle was present at some point in the cardiac cycle in all studies. A redundant flap, defined as flap reaching greater than one half of the way across to the left atrial free wall, was observed in only three (6%) fetuses. Seventeen patients had transatrial Doppler velocities recorded with sample volume placed in the trough of the foramen flap on the left atrial side of the foramen ovale. A triphasic pattern was evident in systole with predominantly right-to-left flow in all fetuses. A biphasic pattern was present in diastole with bidirectional flow in all fetuses; this is toward the left atrium in early diastole and toward the right atrium in late diastole. Maximal right-to-left velocity ranged from 15 to 40 cm/sec (mean, 23 cm/sec) and was always less than or equal to mitral A wave velocity. Maximal left-to-right velocity ranged from 5 to 20 cm/sec (mean, 13 cm/sec). These data indicate that normal foramen ovale size is similar to aortic diameter, and foramen flap angle should reach 30 degrees or greater.(ABSTRACT TRUNCATED AT 250 WORDS)

Fetal echocardiographic diagnosis of congenital heart disease

The delineation of the structural and functional abnormalities of the fetal heart by echocardiography has led to the emergence of a new and vital subspecialty, that of fetal cardiology. Its practitioners are from disciplines such as genetics, obstetrics, and pediatrics, the common interests of which in the well-being of the unborn child have converged as technologic advances in ultrasound have enabled detailed evaluation and sometimes treatment of fetal hemodynamic abnormalities. Each discipline forms an entry point for the identification and referral of the high-risk patient or fetus with a suspected abnormality. As has been shown obstetric cardiac screening of the general population with ultrasound provides the highest yield of cardiac malformations when suspicious findings are referred to a subspecialist in fetal cardiac sonography. As we study the pathogenesis of congenital defects, it is likely that hitherto unidentified high risk populations will be found. The future holds the possibility of meaningful surgical interventions that may change the dismal outcome of fetuses with certain, now lethal cardiac malformations. Patients with hydrops fetalis due to congenital complete heart block are almost certain to die. Intrauterine cardiac pacing has been attempted and is a potentially life-saving procedure. Patients in whom pulmonary underdevelopment occurs because of the cardiac enlargement associated with some types of pulmonary atresia could potentially benefit from intrauterine surgery such as valvotomy. Serial fetal echocardiographic examination of the developing heart with higher resolution equipment during the first trimester may one day pinpoint the exact moment of teratogenesis and lead to more specific treatments designed to restore normal embryogenesis. Such examinations will, when known to be safe themselves, at the very least significantly advance our knowledge of normal cardiac embryogenesis and pathogenesis.

The accuracy of fetal echocardiography in the diagnosis of congenital heart disease

The accuracy of the echocardiographic diagnosis of fetal heart disease in an experienced centre was evaluated by analysing the results achieved during 1987 at the Perinatal Cardiology Unit, Guy's Hospital. In this one year, 978 high-risk patients were referred for fetal echocardiography. Of these, 74 cases were found to have cardiac malformation, 69 of which were predicted from the prenatal study. Of the 69, the autopsy specimen was available for correlative purposes in 41 cases. A postnatal echocardiogram was performed by us in a further 15 cases. The result of autopsy or of a postnatal echocardiogram was obtained from another hospital in 7 cases. Postmortem was refused in 5 cases, while one further case remains alive but has not had a postnatal echocardiogram. Close correlation was achieved between the predicted echocardiographic diagnosis and the anatomical results. Some minor errors in the complete interpretation of a defect were found, particularly in those fetuses in whom image quality was poor, due to early (less than 20 weeks) or late (greater than 34 weeks) gestation or to maternal obesity. Difficulty in echocardiographic interpretation was also experienced in unusual defects. There was one false positive prediction of coarctation of the aorta. One major (total anomalous pulmonary venous drainage) and 5 minor abnormalities (two atrial and three ventricular septal defects) detected after birth were overlooked on the fetal study. Although the echocardiogram in prenatal life is not as accurate as it can be postnatally, with suitable experience a high degree of precision can now be achieved.

Diagnosis of fetal cardiac abnormalities

Images

The Prevalence of Imaging Fetal Cardiac Anatomy

One hundred thirty fetuses were consecutively scanned to determine the prevalence of normal fetal cardiac anatomy. Gestational ages ranged from 20-40 weeks. The four-chamber, five-chamber, and short-axis views were sought in each fetus. Gestational age and fetal spine position were also documented. The fetal spine position was described as spine up, down, left, or right. Gestational ages were categorized into four sonographic age groups; 20-24, 25-29, 30-34, and 35-40 weeks. The number and percentage of echocardiographic views visualized were then calculated for overall population and individual gestational groups in relation to fetal spine position. In the overall gestational group, the fourchamber view was visualized in 99% of the fetuses, whereas the five-chamber and short-axis views were imaged in 95% and 69%, respectively. A three-view average was also calculated for each gestational age group. The highest combined view average was obtained in the 30-34 week group (94%), whereas the lowest was in the 25-29 week gestations (78%). The three-view average was highest in the fetal spine down position (100%), and worst in the fetal spine up position (79%). Spine left demonstrated an 86% mean three-view visualization average, and fetal spine right had a 95% three-view average. These data should aid the fetal echocardiographer in determining what fetal cardiac anatomy can and cannot be seen given the fetal spine position and gestational age.

Echocardiographic diagnosis of fetal heart defects in mid trimester

One hundred and thirty five consecutive fetuses of between 16 and 23 weeks' gestation that were considered to be at high risk of having structural heart defects were examined prospectively to determine the reliability of echocardiography for diagnosing such defects in mid trimester. Each echocardiogram was done in a standard manner and cardiac anatomy was analysed segmentally. Twelve fetuses were excluded from analysis because of lack of follow up. Of the remaining 123 fetuses, 109 had no evidence of heart disease when followed up. In this group the prenatal echocardiogram was normal in 105 and technically inadequate in four; thus there were no false positive diagnoses of heart disease in fetuses subsequently shown to have normal hearts. Fourteen had heart defects at follow up. The serious defect was correctly diagnosed prenatally in 10 of 14 cases, whereas in the other four the prenatal echocardiogram was considered normal. Some errors were made in diagnosing associated segmental defects particularly if the heart disease was complicated. Therapeutic abortion was carried out in seven cases; in five of the fetuses the prenatally diagnosed heart defect was the sole or an important contributing reason for the abortion. We conclude that echocardiography is a reliable method for diagnosing many heart defects in the mid trimester.

Prenatal detection of congenital heart disease: factors affecting obstetric management and survival

Our recent experience in the diagnosis and management of fetal congenital heart disease is presented. During an 18-month period from January 1985 to June 1986, 1757 fetal echocardiograms were performed on a total of 989 antenatal patients. Cardiac anomalies were accurately predicted in 74 cases, 34 of which were associated with extracardiac or chromosomal anomalies. Twenty-three pregnancies were electively terminated. Currently the survival rate for ongoing pregnancies is 17%. A false negative diagnosis was made in 16 cases, the majority involving minor anomalies with a good prognosis and a survival rate of 81%. Prenatal detection of congenital heart disease places the fetus at high risk for chromosomal and extracardiac anomalies. Congenital heart disease detectable during pregnancy is usually severe and associated with a poor long-term prognosis. Termination of the pregnancy may be a reasonable option if a severe anomaly is detected early in pregnancy.

Acceleration time in the aorta and pulmonary artery measured by Doppler echocardiography in the midtrimester normal human fetus

The time to peak velocity was measured by Doppler echocardiography in the pulmonary artery in 102 normal human fetuses (gestational age 16-30 weeks). Time to peak velocity in the aorta was measured in 72. In 58 both measurements could be made in the same fetus. The time to peak velocity was shorter in the pulmonary artery than in the aorta. This difference was statistically significant. This suggests that in the midtrimester fetus mean pressure in the pulmonary artery is higher than in the aorta.