Left atrial isomerism detected in fetal life

Congenital Heart Block

Congenital complete heart block (CCHB) defines atrioventricular conduction abnormalities diagnosed in utero or within the first 27 days of life. Maternal autoimmune disease and congenital heart defects are most commonly responsible. Recent genetic discoveries have highlighted our understanding of the underlying mechanism. Hydroxychloroquine shows promise in preventing autoimmune CCHB. Patients may develop symptomatic bradycardia and cardiomyopathy. The presence of these and other specific findings warrants placement of a permanent pacemaker to relieve symptoms and prevent catastrophic events. The mechanisms, natural history, evaluation, and treatment of patients with or at risk for CCHB are reviewed.

Prenatal diagnosis of hepatic interruption of the inferior vena cava with azygos/hemiazygos continuation without structural heart defects: A case series

OBJECTIVES

To describe fetal spectrum and echocardiographic characteristics of interrupted inferior vena cava (IIVC) with azygos/hemiazygous continuation without other structural heart defects and to evaluate its association with visceral heterotaxy and isomerism, extracardiac and genetic anomalies, and to review neonatal outcome.

METHODS

This was a retrospective study of 14 fetuses with a confirmed diagnosis of IIVC with normal intracardiac anatomy. The following variables were collected; indication for referral, gestational age at diagnosis; associated isomerism and visceral heterotaxy, heart rhythm, genetic and extracardiac abnormalities, and fetal/neonatal outcome.

RESULTS

Among 36 fetuses with IIVC, 14 cases (38.8%) had normal intracardiac anatomy. These IIVC cases correspond to 0.19% (14/7250) of all fetal cardiac examinations, and to 1.5% (14/922) of all cardiac abnormalities. Six patients had visceral abnormalities. Atrial appendage morphology was clearly depicted in three fetuses, both appendages were left. One fetus had bradyarrhythmia revealing atrial ectopic rhythm. Six fetuses did not have any concomitant cardiac or visceral abnormalities, therefore regarded as isolated. All babies were delivered at term with a good prognosis.

CONCLUSION

Our study has shown that almost half of the IIVC cases without intracardiac structural anomalies displayed other findings of isomerism while the other half was isolated benign vascular variant. Therefore, prenatal diagnosis of IIVC should prompt a comprehensive evaluation for cardiac, situs, and visceral anomalies. The outcome is favorable.

Congenital Heart Block

Congenital complete heart block (CCHB) defines atrioventricular conduction abnormalities diagnosed in utero or within the first 27 days of life. Maternal autoimmune disease and congenital heart defects are most commonly responsible. Recent genetic discoveries have highlighted our understanding of the underlying mechanism. Hydroxychloroquine shows promise in preventing autoimmune CCHB. Patients may develop symptomatic bradycardia and cardiomyopathy. The presence of these and other specific findings warrants placement of a permanent pacemaker to relieve symptoms and prevent catastrophic events. The mechanisms, natural history, evaluation, and treatment of patients with or at risk for CCHB are reviewed.

An unusual case of uninterrupted inferior vena cava with accessory hemizygous channel: An incidental finding in a child

Azygos or hemizygous continuation of inferior vena cava (IVC) is diagnosed in the presence of intrahepatic interruption of IVC. We report a case of a 4-year-old, male child presenting with a history of poor weight gain. A detailed evaluation of the child revealed a diagnosis of hemizygous continuation of uninterrupted, but severely obstructed, IVC. This incidental finding has rarely been reported in the literature.

Characteristics and outcomes of fetuses with laterality defects are the current outcomes better? A single center study

Objective: To analyze the more recent outcomes of fetuses with different laterality defects.Material and methods: Out of 1508 fetuses with congenital heart disease (CHD) diagnosed by echocardiography between January 1995 and December 2015, 94 (6.3%) presented abnormal visceroatrial situs: 42 till December 2002 (group 1, analyzed retrospectively) and 52 since then until December 2015 (group 2, analyzed prospectively). Twenty-one had left isomerism (Lisom), 22 right isomerism (Risom), 16 situs inversus- dextrocardia (SVI-dx), 5 situs inversus- levocardia (SVI-levo), and 30 situs solitus-dextrocardia (SSol-dx).Results: Seventy-six cases (81%) had CHD, more frequently complex atrioventricular defect. Eighteen cases showed normal heart: half of subgroups SVI-dx and SVI-levo, a third of SSol-dx. Postoperative mortality in continuing pregnancy in group 2 was 43.7 versus 40% in group 1, lower in SVs-dx (0 versus 50%) and Lisom (33.3 versus 66.7%), worse in Risom (71.4 versus 25%). Total mortality in group 2 was 48.3 versus 55% in group 1, better in Ssol-dx (37.5 versus 50%) and in Lisom (27.4 versus 71.4%). In isolated forms all but one case are alive.Conclusions: Our fetal cases presented a relevant mortality in both periods. The outcomes were slightly better in a more recent era in SSol and Lisom.What is known about this topic?Out of laterality defects, the heterotaxies (i.e. left and right isomerism) are known to be associated to a relevant mortality in fetal and neonatal cases.Heterotaxies have a variable position of the heart, but some authors evaluated only those with dextrocardia in their studies on different laterality defects.Controversial data are presented in the literature for the outcomes of fetuses with laterality defects. Many large studies analyzed the data of a very long time period in which it is opinable to compare the results of the treatment, because of a recent improved management and surgical techniques.What does this study add?Our study presents an experience of a single center with cases of different types of laterality defects observed during a routine fetal echocardiography, not only heterotaxies.The knowledge of different laterality defects and of their characteristics (association with cardiac and extracardiac anomalies or with normal heart) is useful for the prenatal counseling.We compare the postoperative and total mortality in more recent period (since 2003) with respect to the previous era (1995-2002).

Outcome of prenatally diagnosed fetal heterotaxy: systematic review and meta-analysis

OBJECTIVES

The main aim of this systematic review was to evaluate the prevalence and type of associated anomalies in fetuses with heterotaxy diagnosed prenatally on ultrasound; the perinatal outcome of these fetuses was also studied.

METHODS

An electronic search of MEDLINE, EMBASE and CINAHL databases was performed. Only studies reporting the prenatal diagnosis of isomerism were included. Outcomes observed included associated cardiac and extracardiac anomalies, fetal arrhythmia, abnormal karyotype, type of surgical repair and perinatal mortality. The analysis was stratified according to the type of heterotaxy syndrome (left (LAI) or right (RAI) atrial isomerism). Meta-analyses of proportions were used to combine data. Quality assessment of the included studies was performed using the Newcastle-Ottawa Scale for cohort studies.

RESULTS

Sixteen studies (647 fetuses) were included in the analysis. Atrioventricular septal defect was the most common associated major cardiac anomaly found both in fetuses with LAI (pooled proportion (PP), 59.3% (95% CI, 44.0-73.7%)), with obstructive lesions of the right outflow tract occurring in 35.5% of these cases, and in fetuses with RAI (PP, 72.9% (95% CI, 60.4-83.7%)). Fetal arrhythmias occurred in 36.7% (95% CI, 26.9-47.2%) of cases with LAI and were mainly represented by complete atrioventricular block, while this finding was uncommon in cases with RAI (PP, 1.3% (95% CI, 0.2-3.2%)). Abnormal stomach and liver position were found, respectively, in 59.4% (95% CI, 38.1-79.0%) and 32.5% (95% CI, 11.9-57.6%) of cases with LAI, and in 54.5% (95% CI, 38.5-70.1%) and 45.9% (95% CI, 11.3-83.0%) of cases with RAI, while intestinal malrotation was detected in 14.2% (95% CI, 2.5-33.1%) of LAI and 27.1% (95% CI, 7.9-52.0%) of RAI cases. Hydrops developed in 11.8% (95% CI, 2.9-25.6%) of fetuses diagnosed prenatally with LAI. Biventricular repair was accomplished in 78.2% (95% CI, 64.3-89.4%) of cases with LAI, while univentricular repair or palliation was needed in 17.0% (95% CI, 9.7-25.9%); death during or after surgery occurred in 26.8% (95% CI, 4.6-58.7%) of LAI cases. Most children with RAI had univentricular repair and 27.8% (95% CI, 15.5-42.1%) died during or after surgery.

CONCLUSIONS

Fetal heterotaxy is associated with a high prevalence of cardiac and extracardiac anomalies. Approximately one quarter of fetuses with heterotaxy died during or after surgery. Abnormal heart rhythm, especially heart block, is common in fetuses with LAI, while this finding is uncommon in RAI. Biventricular repair was common in LAI while univentricular repair was required in the majority of children affected by RAI. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Prenatal Findings in Left Atrial Isomerism and an Overview of Heterotaxy Syndrome

Heterotaxy syndrome is a rare, complex disorder involving structural cardiac defects in combination with symmetrical development of abdominal viscera that are normally asymmetrical organs. The vast assortment of cardiac manifestations with accompanying abdominal visceral variations determines the prognosis of heterotaxy syndrome. This case study provides an example of the management of this disease, which is unique to the patient. This is a case report of heterotaxy syndrome diagnosed in utero at 29 weeks and 4 days.

Perinatal outcome in fetuses with heterotaxy syndrome and atrioventricular block or bradycardia

Congenital atrioventricular (AV) block is commonly associated with heterotaxy syndrome; together they have reportedly low survival rates (10-25%). However, information about perinatal outcome and predictors of non-survival after prenatal diagnosis of this association is scarce. Therefore, we studied fetuses with heterotaxy syndrome and bradycardia or AV-block diagnosed between 1995 and 2011, and analyzed pre and post-natal variables. The primary outcome was death and the secondary outcome was pacemaker placement. Of the 154 fetuses with heterotaxy syndrome, 91 had polysplenia syndrome, 22/91(24%) with bradycardia or AV-block. Thirteen (59%) patients had sinus bradycardia at diagnosis, 8 (36%) complete AV block, and 1 (5%) second-degree AV-block. Three patients elected for termination of pregnancy (3/22, 14%), 4 had spontaneous fetal demise (4/22, 18%), and 15 (15/22, 68%) were live-born. Of the fetuses with bradycardia/AV-block, 30% presented with hydrops, 20% had ventricular rates <55 beats/min, and 10% had cardiac dysfunction. Excluding termination of pregnancy, 15/19 fetuses (79%) survived to birth. Among the 15 live-born patients, 4 had bradycardia and 11 had AV-block. A further 3 patients died in infancy, all with AV-block who required pacemakers in the neonatal period. Thus, the 1-year survival rate, excluding termination of pregnancy, was 63% (12/19). Of the remaining 12 patients, 9 required pacemaker. Predictors of perinatal death included hydrops (p < 0.0001), ventricular dysfunction (p = 0.002), prematurity (p = 0.04), and low ventricular rates (p = 0.04). In conclusion, we found a higher survival rate (63%) than previously published in patients with heterotaxy syndrome and AV block or bradycardia diagnosed prenatally. Hydrops, cardiac dysfunction, prematurity and low ventricular rates were predictors of death.

Defects in laterality with emphasis on heterotaxy syndromes with asplenia and polysplenia: an autopsy case series at a single institution

Heterotaxy is a rare disease with high morbidity and mortality. Controversy exists over how to classify these syndromes with most cases stratified into asplenia/polysplenia syndromes or right/left isomerism. In an effort to review comprehensively specific pheonotypes associated with heterotaxy syndromes, we reviewed published cases series, adopted a classification scheme based on spleen status, and evaluated autopsy cases retrospectively with abnormal laterality at our institution. We categorized 116 cases as situs inversus totalis, polysplenia, asplenia, and single right-sided spleen. Cardiovascular abnormalities occurred in 87.1% of polysplenia, 90.5% of asplenia, and all cases of single right-sided spleen. For polysplenia, 48.9% had bilateral bilobed lungs, 87% had right-sided stomach, 58.1% had midline symmetric liver, and 60.4% had malrotated intestines. For asplenia, 51.9% had bilateral trilobed lungs, 86.7% had right-sided stomach, 45.8% had symmetric liver, and 65.5% had malrotated intestines. Atrioventricular septal defects occurred in 91.2% of asplenia compared to 56.8% of polysplenia cases. Eight percent had pulmonary/aortic stenosis or atresia. Double outlet right ventricle was more common in polysplenia (32.6%) compared to asplenia (21.4%). Total anomalous systemic venous return was described in 55.6% of polysplenia and total anomalous pulmonary venous connections in 81% of asplenia cases. Greater than half of the cases had no heterotaxy diagnosis. Although, we found similar heterotaxy-associated characteristics, the frequencies differed from previous studies. We found great variation in how heterotaxy-associated defects were described, diagnosed, and reported. Although there are known associated characteristics with the polysplenia/asplenia syndromes, correct identification requires a standardized approach for diagnosis and reporting.

Prenatal diagnosis of atrial isomerism in the Korean population

OBJECTIVE

To report our experiences in the prenatal diagnosis of atrial isomerism and postnatal outcomes.

METHODS

A total of 80 fetuses prenatally diagnosed with atrial isomerism were retrospectively analyzed between 1999 and 2011 at a single institution.

RESULTS

Of 43 fetuses with prenatally diagnosed right atrial isomerism (RAI), 40 cases were analyzed. The diagnostic accuracy was 93%. The main intracardiac anomalies in RAI were atrioventricular septal defect (AVSD), abnormal pulmonary venous connection, bilateral superior vena cava (BSVC), and pulmonary atresia. Among 28 live births, three infants were lost to follow up, and the overall survival rate was 60%. Of 37 fetuses with prenatally diagnosed left atrial isomerism (LAI), 35 were evaluated. The diagnostic accuracy was 97%. The main intracardiac anomalies in LAI were ventricular septal defect, BSVC, AVSD, double outlet right ventricle, and bradyarrhythmia. Among seven patients with bradyarrhythmia, only one showed a complete atrioventricular block. All fetuses had an interrupted inferior vena cava with azygous continuation. The overall survival rate was 90%.

CONCLUSION

Our study confirms the previous findings of fetal atrial isomerism. We also demonstrates a much lower prevalence of AVSD and complete heart block in LAI and a better survival rate in RAI. Although the postnatal outcomes for RAI were worse than those for LAI, successful postnatal surgery with active management improved the survival rate.

Prenatal diagnosis of isolated interrupted inferior vena cava with azygos continuation to superior vena cava

Absence of inferior vena cava is an uncommon congenital abnormality. It is usually associated with other structural anomalies, typically left isomerism. We report a case of interrupted inferior vena cava with azygos continuation diagnosed as an isolated finding during routine prenatal ultrasound scan, confirmed by post-natal echocardiography. Detailed ultrasound examination of the fetal anatomy failed to demonstrate other anomalies. The neonatal course of this fetus was uneventful.

Outcome of left atrial isomerism at a single institution

Left atrial isomerism includes a complex spectrum of cardiac and extracardiac anomalies. The records of all patients with left isomerism born during the period of 1973-2010 and treated at the Children's Hospital, Helsinki were reviewed. The short- and long-term outcomes were studied. The review included 38 patients (50% females). The overall survival with left atrial isomerism was 63% during a median follow-up time of 16 years (range, 4-30 years). Extracardiac anomalies were noted in 14 (37%) of 38 cases. Cardiac defects included dextrocardia in 26%, partially or totally anomalous pulmonary venous return in 29%, common atrium in 50%, atrioventriculoseptal defect in 73%, single ventricle in 40%, ventriculoseptal defect without atrioventricular defect in 11%, transposition in 21%, double outlet of the right ventricle in 26%, pulmonary stenosis or atresia in 61%, and left ventricular outflow obstruction in 24% of the cases. Cardiac arrhythmias were presented in 71% and pacemaker treatment in 29% of the cases. Of the 38 patients, 33 had cardiac surgery. Simple palliative methods were used in 11 cases, single-ventricle palliation in 12 cases, and operation with a biventricular track in 10 cases. In the groups that had surgery, 3 of 11 patients, 3 of 12 patients, and 3 of 10 patients died, respectively. In this review, 14 deaths occurred, associated with extracardiac anomalies in five cases and with cardiac arrhythmia in four cases. Five postoperative deaths occurred. At this writing, all three patients who had heart transplantation are alive. Complicated heart defects associated with severe arrhythmias and extracardiac anomalies contribute to a high mortality rate with left isomerism. Cardiac transplantation was considered a good option for selected patients.

Role of four-dimensional ultrasound (spatiotemporal image correlation and sonography-based automated volume count) in prenatal assessment of atrial morphology in cardiosplenic syndromes

OBJECTIVE

To assess the diagnostic role of four-dimensional ultrasound using spatiotemporal image correlation and Sonography-based Automated Volume Count (STIC-SonoAVC) in the identification of the morphology of the atrial appendages in cases with cardiosplenic syndrome.

METHODS

This was a retrospective investigation of 22 fetuses with cardiosplenic syndromes seen at our institution over a 5-year period from January 2004. As control groups, 10 normal fetuses, five cases with a non-isomeric atrioventricular septal defect and five cases with other congenital heart diseases were also analyzed. For all fetuses, one or more cardiac volume datasets were available for offline analysis. Two-dimensional and four-dimensional echocardiography was carried out in all cases at the time of diagnosis using high quality three-dimensional equipment. Dedicated software was used to assess chamber morphology using the SonoAVC technique, which allows the creation of casts of hollow structures. Two different operators used the software. The first performed all steps up to positioning of the region of interest box. The second operator, who was blinded to clinical information, then rendered the cardiac chambers using the SonoAVC technique. This operator then used the rendered image to subjectively assess atrial morphology.

RESULTS

Suitable rendered images of the cardiac chambers could be produced in 40/42 fetuses. In two cases of left atrial isomerism, advanced (34 weeks) and early (13 weeks) gestational age made it impossible to obtain adequate rendered images. In the remaining 40 cases (13 cases of left atrial isomerism, seven cases of right atrial isomerism, five cases of non-isomeric atrioventricular septal defect, five cases of other congenital heart diseases and 10 normal fetuses), atrial morphology was correctly identified by evaluation of the rendered images.

CONCLUSION

Four-dimensional ultrasound with SonoAVC rendering allows correct identification of the morphology of atrial appendages in all cases of cardiosplenic syndromes in which an adequate cardiac volume dataset can be obtained for analysis.

Right Atrial Isomerism – Preponderance in Asian Fetuses. Using the Stomach-distance ratio as a Possible Diagnostic Tool for Prediction of Right Atrial Isomerism

Introduction: To present the characteristics and spectrum of associated anomalies in right- and left-sided isomerism in our local population and to assess the possibility of using stomach-distance ratio (SDR) of less than 0.34 as a diagnostic tool to predict right atrial isomerism. Materials and Methods: This was a retrospective study of fetuses in our department over a period of 8 years with postnatally confirmed prenatal diagnosis of atrial isomerism. Results: In 22 cases, atrial isomerism was confirmed by post-mortem or postnatal echocardiography. Eighteen (81.8%) fetuses had right isomerism. Their main abnormal ultrasound findings were pulmonary stenosis or atresia (n = 9), atrioventricular septal defect (n = 10), right-sided stomach (n = 9), transposition of great arteries (n = 6), dextrocardia (n = 8), single ventricle (n = 4), juxtaposition of inferior vena cava and descending aorta (n = 5), ventricular septal defect (n = 2), interrupted inferior vena cava with azygous drainage (n = 2) and double outlet right ventricle (n = 3). Four (18.2%) fetuses had left isomerism. Their abnormal ultrasound findings were dextrocardia (n = 3), right-sided stomach (n = 3), atrioventricular septal defect (n = 2), double outlet ventricle (n = 2), ventricular septal defect (n = 1), pulmonary stenosis (n = 2) and interrupted inferior vena cava with azygous drainage (n = 1). 66.7% (12/18) of cases with right isomerism had SDR of less than 0.34 compared to 0% (0/4) of the cases with left isomerism (P = 0.02). Conclusion: Our study suggests an Asian predilection towards right isomerism compared to Western populations. We postulate that there may be racial differences in the expression of these 2 forms of isomerism. The ultrasound findings of complex heart disease and abnormal arrangement of great vessels in abdominal cavity, though important, are varied and non-specific evidence for either form of fetal atrial isomerism. There is a possibility of using the SDR <0.34 (representing stomach proximity to the fetal spine) as a possible diagnostic tool to predict right-sided atrial isomerism. Key words: Azygous vein, Cardiac defects, Dextrocardia, Heterotaxy syndrome, Stomach localisation, Stomach near spine, Visceral heterotaxy

Prenatal diagnosis of omphalocele and left atrial isomerism (polysplenia) including complex congenital heart disease with ventricular noncompaction cardiomyopathy

We report prenatal diagnosis of a rare constellation of findings, including omphalocele and polysplenia (left atrial isomerism [LAI]) with cardiac malformations including ventricular noncompaction (VNC) cardiomyopathy. The heterotaxy syndromes (polysplenia or LAI and asplenia or right atrial isomerism) are rare syndromes in which organs that are usually asymmetric are abnormally symmetric or abnormally positioned. Complex congenital heart disease is frequently associated with heterotaxy, with the heart being substantially affected in both structure and orientation. Heterotaxy has also been occasionally associated with a rare type of cardiomyopathy: VNC, described by Feldt et al and Ozkutlu et al. Omphalocele is a relatively common birth defect that is due to failure of the abdominal wall to close in association with return of the bowel in the first trimester. We report a case in which all of these findings were present. The cardiac findings were previously included in a pathology series on LAI with VNC by Friedberg et al; however, to our knowledge, pre-natal diagnosis of this unique collection of findings has not been reported previously.

Atrioventricular septal defect recently diagnosed by fetal echocardiography: echocardiographic features, associated anomalies, and outcomes

OBJECTIVES

We report our recent experience with atrioventricular septal defect (AVSD) diagnosed in utero.

METHODS

We reviewed fetal echocardiograms diagnosed with AVSD between November 2002 and November 2004, comparing fetuses with and without aneuploidy. We compared results with previous studies.

RESULTS

Twenty (1.8%) fetuses had AVSD. Mean maternal age was 33 years (range 19-43). Mean gestational age was 26 weeks (range 18-38). Indications for fetal echocardiography were: abnormal obstetrical ultrasound (75%), chromosomal anomaly (15%), undetermined (10%). AVSD was an isolated cardiac defect in 5 (25%), associated with double-outlet right ventricle (9) or tetralogy of Fallot (3) in 12 (60%). Four had aortic arch anomalies. Atrioventricular valve regurgitation was mild in 7 (35%) and moderate in 4 (20%). Heart block existed in 2 (10%). Five (25%) with trisomy had Rastelli type A AVSD as a single lesion (odds ratio 24, P < .01). Extracardiac anomalies existed in 6, with and without aneuploidy. Pregnancy was terminated in 4 (20%), neonatal death in 4 (20%), and reparative surgery in 6 (30%), not ascertained in 6.

CONCLUSION

Atrioventricular septal defect is usually an isolated cardiac lesion in fetuses with aneuploidy. In the absence of aneuploidy, fetal AVSD is often associated with conotruncal and aortic arch abnormalities, which are important in determining outcomes. Pregnancy termination and neonatal death continue to be prevalent.

A review of findings in fetal cardiac section drawings, Part 2: high abdominal views

OBJECTIVE

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. This 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

This work reviews 4 fetal 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 should serve as a basis for those doing fetal echocardiography when they encounter an unusual finding.

The area behind the heart in the four-chamber view and the quest for congenital heart defects

OBJECTIVE

To evaluate the spectrum of fetal cardiac defects associated with abnormal sonographic findings in the area behind the heart (ABTH) in the four-chamber view.

METHODS

This study included a retrospective review of 393 fetuses with congenital heart defects (CHD) detected in 2003-2005 at our tertiary referral center and a prospective evaluation of 4666 fetal echocardiograms, including 220 cases of CHD, performed between January 2006 and February 2007. The retrospective and prospective groups did not differ significantly with respect to cardiac anomalies or abnormal findings in the ABTH, allowing us to combine the 613 fetuses with CHD investigated over a 50-month period.

RESULTS

In the study period, 69 fetuses had abnormalities of the ABTH (75% with major CHD). In 28 fetuses, two equally sized vessels ran behind the heart. Of these, 26 had an interrupted inferior vena cava with azygos continuation and two had total anomalous infracardiac pulmonary venous connection. In 41 fetuses, only one vessel was visualized, but the descending thoracic aorta was positioned contralateral to the cardiac apex. Of these, 29 had levocardia with right descending aorta. All of them had a right aortic arch. The remaining 12 had dextrocardia with left descending aorta.

CONCLUSIONS

The ABTH in the four-chamber view is easy to evaluate and offers important diagnostic markers for fetal CHD. Thus, it might enhance the screening performance of the four-chamber view. Attention must be paid to the number of vessels behind the heart and their laterality.

FETAL BRADYCARDIA. A PRACTICAL APPROACH

Fetal bradycardia may herald fetal demise. This article highlights arrhythmic fetal bradycardia rather than bradycardia caused by perinatal distress. We briefly examine the embryonic conduction system's development and physiology and we review the classification, aetiology, evaluation, and approach to fetal bradycardia. Our aim is to provide the clinician with practical information about fetal bradycardia that enlightens causative conditions and aids management.

Heterotaxy syndrome with functional single ventricle: does prenatal diagnosis improve survival?

BACKGROUND

Despite improved outcome for many single ventricle lesions, staged reconstruction for heterotaxy syndrome with a functional single ventricle continues to have a high mortality. Prenatal identification of heterotaxy syndrome may improve long-term survival.

METHODS

Our database was reviewed from January 1996 to December 2004 for patients with heterotaxy syndrome. Assessment was made for prenatal diagnosis and echocardiographic characteristics of heterotaxy syndrome. We sought to assess the accuracy of fetal echocardiography in the diagnosis of heterotaxy syndrome and determine whether prenatal diagnosis and other risk factors have an impact on survival in patients with heterotaxy syndrome.

RESULTS

Of 81 patients that met criteria, 43 (53%) had prenatal diagnosis. Prenatal diagnosis had high specificity and positive predictive value for all findings but had low sensitivity for anomalous pulmonary veins. Among the 70 patients born alive, survival was 60% with median follow-up of 51.4 months (range, 6.5 to 109.7 months). Prenatal diagnosis did not improve survival (p = 0.09). None of the 11 patients with complete heart block (CHB) survived past 3 months of age. Two patients underwent heart transplantation as their first intervention and have survived. CHB and anomalous pulmonary venous connection were associated with shorter duration of survival.

CONCLUSIONS

Prenatal diagnosis of heterotaxy syndrome does not improve survival in patients who undergo single ventricle reconstruction. The most potent risk factors for poor outcome (CHB, anomalous pulmonary veins) are likely not impacted by identification in utero. In light of the poor outcome, cardiac transplantation as an initial therapy may be a viable option for some patients.

Spectrum of cardiovascular disease, accuracy of diagnosis, and outcome in fetal heterotaxy syndrome

Because there is a paucity of information regarding the diagnosis and outcomes of fetal heterotaxy syndrome (HS), this study sought to determine the spectrum of cardiac pathology, accuracy of diagnosis, and outcome of fetal HS. All cases of fetal HS encountered in the investigators' institution over a 10-year period through 2002 were identified. Prenatal and postnatal echocardiograms and medical records were reviewed. Seventy-one fetuses were diagnosed with HS, including 48 with left atrial isomerism (LAI) and 23 with right atrial isomerism (RAI). For LAI and RAI, most intracardiac lesions, the pulmonary venous connections, and superior vena caval anatomy were correctly diagnosed in utero (93%, 86%, and 77% accuracy, respectively), whereas hepatic venous connections and inferior vena caval-atrial connections in RAI were difficult to define (65% and 56% accuracy, respectively). Of 32 continued and followed pregnancies with LAI, 22 are currently alive at 48 +/- 30 months. Heart block and associated major extracardiac pathology were significantly more common in nonsurvivors with fetal LAI (p = 0.007 and 0.024, respectively). Outcomes were even worse for prenatally diagnosed RAI: of 14 continued pregnancies, only 3 are currently alive. In conclusion, fetal HS is associated with a broad spectrum of cardiac pathology, which can be diagnosed accurately in utero. Fetal LAI is associated with a mortality of 31%, with heart block and extracardiac pathology as primary risk factors for perinatal mortality. The outcome of prenatally diagnosed RAI is poor.

Clinical Features, Management, and Outcome of Children With Fetal and Postnatal Diagnoses of Isomerism Syndromes

Background— Isomerism is associated with a complex spectrum of anomalies. There is paucity of data on prenatally detected cases.

Methods and Results— Between January 1990 and February 2004, 83 of 166 cases (50%) had a prenatal diagnosis of left isomerism (LAI; 52 of 97) or right isomerism (RAI; 31 of 69) at our institution. The spectrum of anomalies, management, and outcomes was compared for fetal and postnatal diagnoses of LAI and RAI. RAI more often than LAI was associated with AV septal defect (90% versus 56%; P <0.0001), pulmonary outflow obstruction (91% versus 37%; P <0.0001), total anomalous pulmonary venous drainage (73% versus 13%; P <0.0001), and abnormal VA connections (68% versus 33%; P <0.0001), whereas inferior vena cava interruption (3% versus 93%; P <0.0001), complete AV block (0% versus 13%; P =0.004), aortic obstruction (6% versus 33%; P <0.0001), and extracardiac defects (5% versus 25%; P =0.006) were less common. The spectrum of lesions was comparable for fetal and postnatal cases, except for AV block (fetal, 25%; postnatal, 0%; P =0.0002) and AV septal defect (fetal, 67%; postnatal, 42%; P =0.023) in LAI. Fetal demise was due mainly to pregnancy termination (LAI, 42%; RAI, 45%). Survival of actively managed children with LAI was significantly better than for those with RAI ( P <0.0001) but did not differ with regard to fetal versus postnatal diagnosis. Most LAI cases required no intervention or underwent successful biventricular cardiac surgery (65%), unlike RAI cases (13%; P <0.0001).

Conclusions— Prenatal diagnosis did not affect overall survival despite facilitated care. The prognosis of RAI was worse compared with LAI because of more complex associated cardiac defects and the inability to perform successful surgical procedures.

Fetal echocardiographic evaluation of atrial morphology and the prediction of laterality in cases of heterotaxy syndromes

OBJECTIVE

To evaluate whether abnormal atrial morphology, which is well recognized in autopsy series, is detectable by fetal echocardiographic examination of the four-chamber view, and can therefore be utilized to differentiate left from right isomerism in heterotaxy syndromes.

METHODS

This study was a retrospective review of 30 cases with prenatally diagnosed heterotaxy syndromes. Ultrasound video recordings and still images were reviewed with respect to atrial morphology in the four-chamber view. In 25 cases the morphology of both atria was sufficiently well visualized on the recordings to be evaluated and only these were included in the study.

RESULTS

Two types of atrial morphology were distinguished in our cohort: a sickle-shape with the tip pointing laterally and apically, and a blunt shape resembling the usual atrial appearance in the four-chamber view. Nineteen out of the 25 cases (76%) presented with isomerism of the atria in the four-chamber view. Thirteen had bilateral sickle-shaped atrial morphology, all associated with left isomerism. Six had bilateral blunt-shaped atrial morphology, all associated with right isomerism. The atria of the remaining six cases were not isomeric, the right atrium being sickle-shaped and the left blunt-shaped. Five of the latter cases were associated with left and one with right isomerism.

CONCLUSIONS

The majority of prenatally diagnosed heterotaxy syndromes seem to present with isomeric atrial morphology in the four-chamber view. In these cases a differentiation between left and right isomerism can be based on the two distinct types of atrial morphology. This may further enhance the prenatal differentiation of these syndromes.

Isomerism of the left atrial appendage associated with ventricular noncompaction

This study investigated the rare association of ventricular noncompaction with isomerism of the left atrial appendage and heart block, demonstrating a dire prognosis for this condition. Prenatal recognition is possible by ultrasound, facilitating appropriate prenatal counseling.

Totally anomalous pulmonary venous connection and complex congenital heart disease: prenatal echocardiographic diagnosis and prognosis

OBJECTIVE

The purpose of this study was to determine the accuracy of prenatal cardiac diagnosis, prognosis, and outcome of totally anomalous pulmonary venous connection (TAPVC) and to determine echocardiographic clues in the prenatal diagnosis of isolated TAPVC or TAPVC in association with other complex congenital heart disease (CHD).

METHODS

We reviewed our 13-year experience of prenatal diagnosis of TAPVC. Thirteen fetuses were identified with the diagnoses of TAPVC. We systematically analyzed the individual pulmonary veins by color and pulsed Doppler imaging, the presence of a pulmonary venous confluence, the pulsed and color Doppler evaluation of the vertical vein, and sites of connections. Prenatal diagnosis was confirmed by postnatal echocardiography, cardiac catheterization, surgery, or autopsy.

RESULTS

The mean gestational age at diagnosis of TAPVC was 26.3 weeks (range, 20-33 weeks). There were 8 fetuses with TAPVC and right isomerism, 3 fetuses with other associated CHD, and 2 with isolated TAPVC. There were 7 fetuses with supracardiac TAPVC, 4 with infracardiac TAPVC, and 2 with mixed TAPVC. Pulmonary vein color and pulsed Doppler data were available in 10 of 13 fetuses. The pulmonary venous confluence was visualized in all fetuses except 1. The vertical vein was visualized in all fetuses. Five fetuses had suspected signs of obstruction. The diagnosis was confirmed postnatally or at autopsy in 12 cases. Eight patients underwent surgery; 6 died, and 2 were alive. Two patients had compassionate care and died; 3 pregnancies were terminated.

CONCLUSIONS

It is possible to diagnose accurately complex CHD, including the pulmonary venous connections. When diagnosed prenatally, TAPVC carries a poor prognosis.

Heterotaxy syndrome -- asplenia and polysplenia as indicators of visceral malposition and complex congenital heart disease

Heterotaxy results from failure of the developing embryo to establish normal left-right asymmetry. Typical manifestations include abnormal symmetry and malposition of the thoraco-abdominal organs and vessels, complex congenital heart disease and extracardiac defects involving midline-associated structures. The spleen is almost always affected, and there is syndromic clustering of the malformations corresponding to the type of splenic abnormality present. This review outlines the embryologic and genetic background of the heterotaxy syndrome as well as the characteristic anatomic features, clinical manifestations, and diagnostic clues of its two main presentations with asplenia or polysplenia.

Atrioventricular block detected in fetal life: associated anomalies and potential prognostic markers

OBJECTIVES

To assess the spectrum of anomalies associated with fetal heart block and to identify possible prognostic markers.

METHODS

Retrospective review of all cases of second- or third-degree heart block identified in two tertiary referral centers in Germany (Bonn and Lübeck) and one in the USA (Baltimore).

RESULTS

Sixty fetuses with heart block were identified in the study period. Thirty-two had complex cardiac malformations, 31 of them associated with left isomerism. The outcomes of these fetuses were 22 terminations of pregnancy (TOP), three intrauterine fetal deaths (IUFD), three neonatal deaths (NND), two childhood deaths (CD) and there were two survivors. In 20 cases without complex cardiac malformations maternal antinuclear-antibodies were detected. Their outcomes were 2 TOP, 1 IUFD, 1 NND and 16 survived. The remaining eight cases had neither complex cardiac malformations nor associated maternal antibodies. Their outcomes were 1 TOP, 2 IUFD, 2 NND and 3 survived. After exclusion of terminated cases, hydrops as well as the presence of cardiac defects was significantly associated with non-survival (P < 0.01). The cardiothoracic circumference ratio was significantly higher in hydropic fetuses and significantly negatively correlated with survival in immune-mediated cases (P < 0.01). Atrial and ventricular frequencies and their evolution did not accurately predict fetal or neonatal outcome. Sympathomimetic treatment in seven cases was not associated with favorable fetal outcome in cases of hydrops or cardiac malformations.

CONCLUSIONS

The most important marker predicting adverse outcome in cases of heart block is fetal hydrops, followed by the association with complex cardiac malformations. Cases without cardiac malformations have a significantly better prognosis, especially in the absence of severe cardiomegaly.

The syndrome of left isomerism: sonographic findings and outcome in prenatally diagnosed cases

OBJECTIVE

The purpose of this study was to evaluate the accuracy of the prenatal diagnosis of left isomerism and to assess possible diagnostic and prognostic markers.

METHODS

We conducted a retrospective review of all previously unpublished cases of left isomerism diagnosed in the prenatal and postnatal periods in 2 tertiary referral centers in Germany over 15 years.

RESULTS

Among 34 fetuses, 31 had a correct prenatal diagnosis of left isomerism; 31 had an interruption of the inferior vena cava with azygos continuation; 22 had different types of viscerocardiac heterotaxy; 13 had heart block; and 28 had cardiac defects, with a high prevalence of atrioventricular septal defects (n = 24), right outflow tract obstruction (n = 11), double-outlet right ventricles (n = 6), and anomalous pulmonary venous return (n = 6). Among the 34 cases, 9 underwent termination of pregnancy; 2 fetuses died in utero; 5 children died in the neonatal period; and 4 children died in infancy. Only the presence of heart block and hydrops was significantly correlated with nonsurvival (P < .05). Fourteen children survived, with a mean follow-up +/- SD of 2.9 +/- 2.6 years. Three survivors underwent single-ventricle palliation, and 1 had successful biventricular repair. Three children were awaiting cardiac repair. The remaining 7 children had minor or no associated cardiac defects and were doing well.

CONCLUSIONS

Prenatal diagnosis of left isomerism is feasible, with high accuracy. Important diagnostic pointers are viscerocardiac heterotaxy, complex cardiac malformations, heart block, and interruption of the inferior vena cava. The mortality in fetuses and neonates is high in the presence of heart block and hydrops, whereas the cardiac defects influence the long-term outcome.

First-trimester fetal heart block and increased nuchal translucency: an indication for early fetal echocardiography

Prevalence of congenital heart disease increases with nuchal translucency (NT) thickness. First-trimester fetal bradycardia may result from heart block associated with complex congenital heart disease. We report two cases detected in the first trimester of pregnancy, in which both fetuses showed an increased nuchal translucency and bradycardia. Fetal karyotype was normal in both fetuses. First-trimester fetal echocardiography was performed and, in both cases, complex congenital heart disease was diagnosed. We discuss the added role of fetal heart rate in first-trimester ultrasound screening, in fetuses with increased nuchal translucency and normal karyotype. We stress, as well, the importance of echocardiography performed in the first trimester as a potential tool for early diagnosis in selected cases.

Diagnosis and outcome of dextrocardia diagnosed in the fetus

A retrospective review of 5,539 fetal echocardiograms over a 22-year period revealed 85 cases of dextrocardia. In primary dextrocardia (46 cases), the incidence of situs solitus, inversus, and ambiguous, was similar and associated with a high incidence of complex cardiac malformations in situs solitus and situs ambiguous. Secondary dextrocardia (39 cases) was due to intrathoracic displacement and, when caused by diaphragmatic hernia, was associated with cardiac malformations in 31% of cases. Even in complex cases, fetal echocardiography was highly accurate; therefore, specific counseling can be given to parents.

Right atrial isomerism in four siblings

Heterotaxy syndromes, right or left atrial isomerism, result from disruption of left-right axis determination and their manifestations include complicated heart defects. Recent studies in model organisms have revealed complex genetic pathways and several genes involved in this process. In affected humans, however, molecular studies have identified mutations in a small number of individuals, while in most the cause remains unknown. Furthermore, although family data suggest, autosomal recessive inheritance, such genes have not yet been identified. We have studied six members of a family, four children affected with right atrial isomerism (RAI) and their healthy parents, for disturbances of left-right axis development. The children, one female and three males who all had complicated heart defects, succumbed and had an autopsy. Their nonconsanguineous parents were examined by cardiac and abdominal ultrasound or MRI. In all four children the heart defects included single ventricle with dysplastic atrioventricular (AV) valve, total anomalous pulmonary venous drainage (TAPVD), and malposition of great arteries (MGA) with pulmonary stenosis (PS). All had asplenia; two also had dextrocardia and abdominal situs inversus. The diagnosis of RAI was made postnatally in the first child and prenatally in others. Two siblings had no surgery and died as a newborn, one with obstructed supracardiac TAPVD and the other with regurgitating AV valve. Two children underwent heart surgery. One had repair of obstructive infracardiac TAPVD but died in infancy. The other underwent both hemi-Fontan operation and heart transplantation but died at the age of 2 years. This is the first report describing four children with RAI in the same family. The occurrence of RAI in male and female siblings without any indication of left-right axis abnormalities in their parents suggests autosomal recessive inheritance of human isomerism.

Prenatal diagnosis of cardiosplenic syndromes: a 10-year experience

OBJECTIVE

To assess the accuracy of fetal echocardiography in the prenatal diagnosis of cardiosplenic syndromes and the spectrum of associated anomalies.

METHODS

This was a retrospective survey of fetuses in our databases over a period of 10 years with postnatally confirmed prenatal diagnosis of cardiosplenic syndromes.

RESULTS

In 32 of 35 fetuses the prenatal diagnosis of cardiosplenic syndromes was confirmed postpartum. Twenty-two fetuses had left isomerism. Their main prenatal ultrasound features were interrupted inferior vena cava (n = 21), complete atrioventricular septal defect (n = 15), viscerocardiac heterotaxy (n = 15), persistent bradyarrhythmia (n = 12) and fetal hydrops or nuchal edema (n = 12). Twelve pregnancies were terminated, two fetuses were stillborn and eight infants survived. Ten fetuses had right isomerism. Their main sonographic features were juxtaposition of the descending aorta and inferior vena cava (n = 7), complete atrioventricular septal defect (n = 7), left persistent superior vena cava (n = 6) and viscerocardiac heterotaxy (n = 6). In this group there was one stillbirth, five infant deaths and four survivors. The overall survival rate and spectrum of other cardiac malformations were similar between the two groups. Prenatal diagnosis of other visceral features of cardiosplenic syndromes was inconsistent.

CONCLUSION

Cardiosplenic syndromes can be diagnosed with high accuracy by prenatal sonography. A diagnosis of left isomerism should be strongly suggested in the presence of a combination of at least two of the following: (1) complete atrioventricular septal defect or other structural heart disease; (2) interruption of inferior vena cava with azygos continuation; (3) early fetal heart block; (4) viscerocardiac heterotaxy. Right isomerism should be suspected in the presence of a combination of at least two of the following: (1) structural heart disease, namely complete atrioventricular septal defect; (2) juxtaposition of inferior vena cava and descending aorta; (3) viscerocardiac heterotaxy.

Ivemark syndrome with agenesis of the corpus callosum: a case report with a review of the literature

Asplenia associated with situs ambiguus, symmetric liver, bilateral trilobulated lungs, and a complex heart defect was diagnosed on autopsy in a 14-day-old infant. Furthermore, examination of the brain displayed agenesis of the corpus callosum (ACC) with pachygyria and hydrocephalus. The characteristic association of asplenia with visceroatrial heterotaxia is traditionally named after the Swedish pediatrician, Ivemark. Although exceptional, association of Ivemark syndrome with callosal agenesis has been reported recently. The concept of 'developmental fields' describes morphogenetically reactive units of the embryo determining and controlling the development of complex structures in a hierarchical manner. Lateralization defects such as situs inversus, asplenia or polysplenia due to defective left-right axis development, as well as decussation defects such as ACC, are considered as defects of the primary developmental field. Therefore, additional callosal agenesis in Ivemark syndrome may be a coherent and synchronic defect in the primary developmental field rather than a causally independent malformation.

Intrauterine diagnosis of heterotaxy syndrome

BACKGROUND

Heterotaxy syndrome, including right isomerism and left isomerism, is characterized by an abnormal symmetry of the viscera and veins and is frequently associated with complex cardiac anomalies. We sought to define the feasibility of in utero diagnosis and the postnatal outcome.

METHODS

Patients with heterotaxy syndrome were identified from 579 fetal echocardiograms performed from January 1994 to December 1998. The diagnosis was made on the basis of the fetal echocardiographic findings and was confirmed with autopsy or postnatal evaluation.

RESULTS

A total of 25 fetuses with right isomerism and 4 with left isomerism constitute the study population. The pregnancies of 7 fetuses (6 right and 1 left isomerism) were terminated before the 24th gestational week and subjected to autopsy. Twelve fetuses (10 right and 2 left isomerism) were lost to follow-up. Nine with right isomerism and 1 with left isomerism were delivered and underwent palliation. Among them, 5 patients (56%) with right isomerism died and more than half of the deaths occurred during infancy. The major cardiac anomalies detected and confirmed with postnatal evaluation or autopsy in fetuses with right isomerism were total anomalous pulmonary venous connection (6/15; 40%), common atrium (15/15; 100%), complete atrioventricular canal (15/15; 100%), double outlet right ventricle (15/15; 100%), and pulmonary stenosis (11/15; 73%). The major cardiac anomalies in fetuses with left isomerism were interruption of inferior vena cava (2/2; 100%), common atrium (1/2; 50%), and complete atrioventricular canal (1/2; 50%). Undetected lesions with fetal echocardiogram were abnormal pulmonary venous return to systemic veins in 1 case (sensitivity, 83%; 5/6; and specificity, 90%; 9/10) and outflow obstruction in 1 case (sensitivity, 91%; 11/12; and specificity, 67%; 2/3). Different patterns of rhythm disturbances were identified: supraventricular tachycardia in 1 case with right isomerism and sinus bradycardia with junctional rhythm in 3 cases with left isomerism (2 of them lost to follow-up). After birth, another 2 patients with right isomerism had supraventricular tachycardia, and 1 with left isomerism had sinus bradycardia develop at age 2 years.

CONCLUSION

Heterotaxy syndrome is usually detected in fetuses with the sonographic cardiac abnormalities. Visualization of the pulmonary venous return and outflow obstruction and characterization of the rhythm disturbances are feasible. However, in spite of prenatal diagnosis, the prognosis remains poor.

In utero diagnosis of obstructed supracardiac total anomalous pulmonary venous connection in a patient with right atrial isomerism and asplenia

We describe a rare case of right atrial isomerism, levocardia, right-side stomach, obstructed supracardiac total anomalous pulmonary venous connection, double outlet right ventricle with complete atrioventricular septal defect and absent spleen. From the pulmonary venous confluence behind the atrium an ascending as well as a descending vertical vein communicated with the systemic venous system in the supracardiac as well as the infracardiac position. The pulsed and color Doppler examination of the individual pulmonary veins as well as of the vertical vein helped in making the diagnosis of obstructed total anomalous pulmonary venous connection. The diagnosis was made by fetal echocardiographic examination at 22 weeks of gestation and confirmed on postnatal echocardiography, cardiac catheterization, and at surgery.

Outcomes of left atrial isomerism over a 28-year period at a single institution

OBJECTIVES

We determined long-term outcomes in a large cohort with left atrial isomerism (LAI).

BACKGROUND

Left atrial isomerism is associated with a complex spectrum of cardiac and noncardiac anomalies that may impact on outcomes.

METHODS

The records of all patients with LAI, born between 1970 and 1998, and treated at one center were reviewed. Kaplan-Meier survival was estimated, and independent factors associated with time-related death were identified.

RESULTS

There were 163 patients (63% women), and extracardiac anomalies were noted in 36%, including biliary atresia in 10%. Cardiac defects included interrupted inferior caval vein in 92%, anomalous pulmonary veins in 56%, atrioventricular septal defect in 49%, pulmonary atresia or stenosis in 28% and aortic coarctation in 16%, with congenital atrioventricular block in 7%. Of 22 patients with a normal heart, 18% died of extracardiac anomalies. Of 71 patients with hearts suitable for biventricular repair, 62 (87%) had surgery, with survival of 80% at one year, 71% at five years, 66% at 10 years and 63% after 15 years. Of 70 patients with unbalanced cardiac defects suitable for single-ventricle palliation, 47 (67%) had surgery, with survival of 73% at one year, 61% at five years, 53% at 10 years and 48% at 15 years (p < 0.001). Independent factors associated with time-related death included congenital atrioventricular block, aortic coarctation, single ventricle, biliary atresia and other gastrointestinal malformations.

CONCLUSIONS

Both cardiac and noncardiac anomalies contribute to a high mortality with LAI. Cardiac transplantation may need to be a considered a primary option for selected high-risk patients.

Prenatal diagnosis of abnormalities of the fetal venous system

OBJECTIVE

To present our experience in the prenatal diagnosis of anomalies of fetal veins using high-resolution color Doppler ultrasound.

DESIGN

An observational study of 16 fetuses with abnormalities of the umbilical, portal, hepatic and caval venous system being diagnosed at the Division of Prenatal Diagnosis and Therapy (Bonn, Germany) over the past 5 years. The abnormality of the venous system, the underlying embryologic disorder and the outcome of the pregnancy are presented and compared with the literature.

RESULTS

In group A, eight fetuses had an abnormal course of the umbilical vein with a patent (n = 3) or absent (n = 5) ductus venosus. No portal veins and absent or abnormal hepatic veins were visualized by color Doppler sonography. Six fetuses (75%) did not have an associated malformation and have survived. Two pregnancies with fetal hydrops due to a small heart and to Turner's syndrome were terminated or ended in fetal demise. In group B, seven of eight fetuses with an abnormal caval system had a situs ambiguus or an atrial isomerism. A cardiac defect was detected in six cases (86%). These six pregnancies ended in four terminations of pregnancy and two infant deaths due to the severity of the congenital cardiac defect. One child with a normal heart and a child with an isolated abnormal course of the lower inferior vena cava are developing well.

CONCLUSIONS

In a targeted fetal scan the course of the umbilical vein, ductus venosus, the portal and hepatic veins and inferior vena cava should be carefully examined using color Doppler. Any suspicious finding should be followed by a detailed assessment of the specificity of this abnormality taking into consideration the embryologic development of the fetal venous system together with the associated malformations.

Progression of congenital heart disease in the prenatal period

BACKGROUND

Prenatal echocardiography has shown evidence of prenatal development of congenital heart disease. Prenatal cardiac anatomy, chamber size and function change during gestation, so that the appearance of cardiac structure in abnormal hearts may be different from that which is usually seen postnatally.

METHODS

Published prenatal echocardiographic studies were reviewed and in utero development of congenital heart disease from midtrimester to the early postnatal period is discussed.

RESULTS

The growth of the great vessels and ventricles is reduced in fetuses with ventricular outflow obstruction. Valve regurgitation may progress. The foramen ovale and ductus arteriosus have been reported to become restrictive in utero in several settings. Pulmonary vascular obstructive changes may progress prenatally. Fetal arrhythmia (both bradycardia and tachycardia) may develop in utero. Development of congestive heart failure is a very important issue during follow up of fetuses with significant cardiac or extracardiac problems. Some may progress to fetal hydrops and prognosis of the affected fetuses is usually very poor.

CONCLUSIONS

Correct knowledge of possible development is important for accurate prenatal diagnosis. Information on prenatal progression of the cardiac anomaly is also important to make plans for follow up and perinatal management, to predict outcomes and to counsel family. Furthermore, the benefits of prenatal treatment instead of postnatal treatment should be assessed by the accurate prediction of the progression of the cardiac problem in utero. Further extensive studies using a large number of cases is required to predict progression accurately. In addition, further studies for elucidating the mechanisms of progression is important to provide better outcomes for fetuses with various congenital heart diseases.

Sequential segmental approach to fetal congenital heart disease

The sequential segmental approach is now universally used in the diagnosis of congenital heart disease. Its utilization during fetal sonography has not been well described. In this review, we show how the fetal heart can be approached in a sequential segmental manner by using six basic sonographic views. The transverse view of the fetal upper abdomen is obtained to determine the arrangement of the abdominal organs, which, in most cases, provides the important clues to the determination of the atrial arrangement. The four-chamber view is obtained to evaluate the atrioventricular junctions. The views of the left and right ventricular outflow tracts are obtained to evaluate the ventriculoarterial junctions. The three-vessel view and the aortic arch view are obtained for the evaluation of the arrangement and size of the great arteries, which provides the additional clues to the diagnosis of the abnormalities involving the ventriculoarterial junctions and the great arteries. The standard protocol to acquire these six basic views is also introduced.

Pediatric echocardiography: applications and limitations

Echocardiography is an extraordinarily useful imaging technique in fetuses, infants, children, and adolescents. Recent technologic innovations have expanded its versatility in the pediatric population. However, limited societal resources, limitations inherent to ultrasound imaging, and numerous imaging options even within the field of pediatric echocardiography necessitate the discriminate and thoughtful use of echocardiography in children. The clinical assessment remains a critical prelude to echocardiographic examination of the pediatric cardiovascular system.

Diagnosis of heterotaxy syndrome by fetal echocardiography

We report a series of 13 consecutive patients diagnosed in utero with heterotaxy syndrome in which we found a slight predominance (8 of 13) of fetuses with right atrial isomerism. In previous studies in which diagnosis of left or right isomerism was made based upon findings at fetal echocardiography, there has been a preponderance of infants (95%) diagnosed with left isomerism.

Supraventricular tachycardia in patients with right atrial isomerism

OBJECTIVES

To clarify the prevalence and mechanism of supraventricular tachycardia in patients with right atrial isomerism.

BACKGROUND

Paired SA and dual atrioventricular (AV) nodes have been described in patients with right atrial isomerism. However, the clinical significance remains unclear.

METHODS

From 1987 to 1996, a total of 101 patients (61 male, 40 female) and four fetuses were identified with right atrial isomerism. The diagnosis of supraventricular tachycardia exclude the tachycardia with prolonged QRS duration or AV dissociation, and primary atrial tachycardia.

RESULTS

The median follow-up duration was 38 months (range 0.2-270 months). Supraventricular tachycardia was documented in 25 patients (24.8%) and one fetus (25%) (onset age ranged from prenatal to 14 years old; median 4 years old). Actuarial Kaplan-Meier analysis revealed that the probability of being free from tachycardia was 67% and 50% at 6 and 10 years of age, respectively. These tachycardias could be converted by vagal maneuvers in one, verapamil in seven, propranolol in four, digoxin in two, procainamide in one, and rapid pacing in five. Spontaneous conversion was noted in six (including the fetus). Seven cases had received electrophysiological studies. Reciprocating AV tachycardia could be induced in five and echo beats in one. The tachycardia in three patients was documented as incorporating a posterior AV node (antegrade) and an anterior or a lateral AV node (retrograde). Two of them received radiofrequency ablation. Successful ablation in both was obtained by delivering energy during tachycardia, aimed at the earliest retrograde atrial activity and accompanied by junctional ectopic rhythm. The patient with echo beats developed tachycardia soon after operation.

CONCLUSIONS

Supraventricular tachycardia is common in patients with right atrial isomerism and can occur during the prenatal stage. Drugs to slow conduction through the AV node may help to terminate the tachycardia. Radiofrequency ablation is a safe and effective treatment alternative to eliminate tachycardia.

Peculiarities of prevalence and morphology of congenital heart disease detected in utero

Intrauterine echocardiography is changing our knowledge of congenital heart disease; cardiac defects diagnosed in utero have distinctive features of both prevalence and morphology when compared with those observed just after birth. We reviewed a series of 171 fetal heart conditions: 148 were diagnosed at intrauterine echocardiography, the diagnosis being verified at autopsy in 41, and 23 were observed at the postmortem only. Peculiarities of prevalence consisted in an excess of various defects, such as hypoplastic left heart syndrome, atrial isomerism, pulmonary atresia, and atrioventricular and atrial septal defects, and in a reduced number of completely different conditions, such as transposition of great arteries and aortic coarctation. Differences in prevalence have been attributed to difficulties in diagnosing some particular anomalies in utero, to the selection of pregnancies undergoing screening, and to the special intrauterine evidence of some heart defects. Peculiarities in morphology result from the coexistence with extracardiac malformations, from the changes in shape conditioned by fetal hemodynamics, and from the intrauterine evolution of the morphology of some malformations. We concluded that the knowledge of these characteristic traits was helpful to cardiac pathologists, pediatric cardiologists, and obstetricians, and allowed the re-evaluation of the role of hemodynamic factors in remodeling the malformed cardiovascular appara-tus.