Assessment of cardiac angle in fetuses with congenital heart disease at risk of 22q11.2 deletion.

OBJECTIVES: To evaluate fetal cardiac angle as a screening tool for 22q11.2 deletion among cases with cardiac anomalies known to be associated with this genetic condition, to examine the correlation of fetal cardiac angle with thymic-thoracic (TT)-ratio, and to assess the performance of TT ratio as a covariate in screening for 22q11.2 deletion. METHODS: This was a retrospective cohort study that reviewed the records of 74 cases with cardiac anomalies known to be associated with 22q11.2 deletion (tetralogy of Fallot, common arterial trunk, interrupted aortic arch and right aortic arch) that were diagnosed between 2007 and 2013. The karyotype was known in all cases. The fetal cardiac angle and TT-ratio were measured using stored three-dimensional spatiotemporal image correlation volume datasets and compared in those with del.22q11.2 and those without. RESULTS: Of the 74 cases reviewed, 16 had 22q11.2 deletion. The mean cardiac angle was larger in the cases with 22q11.2 deletion than in those without (68.6° vs 58.7°, respectively; P = 0.02). Multivariate regression analysis showed an association between cardiac angle and TT-ratio in fetuses with 22q11.2 deletion (r(2) = 0.33; P = 0.02) but not in those with a normal karyotype (P = 0.4). Logistic regression analysis demonstrated that fetal cardiac angle, but not TT-ratio, is an independent predictor of 22q11.2 deletion among fetuses with 22q11.2 deletion-associated cardiac anomalies (P = 0.02; area under the receiver-operating characteristics curve = 0.69). CONCLUSIONS: An enlarged fetal cardiac angle is an independent predictor of 22q11.2 deletion among fetuses with 22q11.2 deletion-associated cardiac anomalies. However, its performance as a single variable in a screening model is not sufficient to guide management decisions regarding invasive testing.

Outcome and requirement for surgical repair following prenatal diagnosis of ventricular septal defect.

OBJECTIVE: To document outcome following prenatal diagnosis of ventricular septal defects (VSDs), particularly associated anomalies and the requirement for surgical closure of the defect. METHODS: All cases of prenatal diagnosis of a VSD made by fetal cardiologists at a tertiary fetal medicine referral center in the period January 2002 to December 2011 were extracted from our database. Data regarding fetal cardiac diagnosis, extracardiac anomalies, nuchal translucency thickness and karyotype were noted. RESULTS: A total of 171 cases fulfilled our selection criteria. Of these, 69% were diagnosed with a perimembranous VSD and 31% with a muscular defect. The median gestational age at diagnosis was 21 + 6 (range, 12 + 0 to 37 + 3) weeks. Owing to severe extracardiac or genetic conditions, pregnancy resulted in intrauterine death or termination in 49% cases, and postnatal death occurred in 9% of cases. Seventy-two babies were liveborn, and were regarded as potential surgical candidates if hemodynamics suggested that surgery was indicated. Surgical closure of the VSD proved necessary in 50% of the patients with a perimembranous VSD and 13% of those with a muscular VSD. All patients operated on survived surgical repair. No karyotypic abnormalities were identified in fetuses with VSDs that had normal first-trimester screening and no other sonographic abnormalities. CONCLUSIONS: A high proportion of VSDs diagnosed during fetal life (29%) require postnatal surgical intervention. The assessment of hemodynamic significance from fetal echocardiography is imperfect. The presence of extracardiac abnormalities or abnormal results on first-trimester screening has a major impact on the incidence of karyotypic abnormalities in affected fetuses. This should inform discussions with parents about invasive testing.

Reliability of fetal thymus measurement in prediction of 22q11.2 deletion: a retrospective study using four-dimensional spatiotemporal image correlation volumes.

OBJECTIVES: To evaluate the thymic-thoracic ratio (TT-ratio) method in assessment of the fetal thymus in normal fetuses and in those with cardiac abnormalities, in the presence or absence of 22q11.2 deletion. METHOD: Database records were reviewed for cases of conotruncal and arch abnormalities found on fetal echocardiography between January 2007 and September 2011. The 22q11.2 deletion status was retrieved and cases in which this was not known were excluded from the analysis, as were fetuses with aneuploidy or other genetic disorders. An additional 55 normal fetuses were analyzed as a control group. The TT-ratio was measured retrospectively using stored spatiotemporal image correlation (STIC) volume datasets. RESULTS: Sixty-nine fetuses with relevant cardiac diagnoses were identified and, of these, 18 (26%) had 22q11.2 deletion. The mean gestational age at diagnosis was 22 weeks. Significant pairwise differences, but also overlap, were observed between all three groups (i.e. fetuses with heart defects with and without the 22q11.2 deletion and controls). The mean TT-ratio was 0.44 in our normal control group and was significantly smaller in fetuses with 22q11.2 deletion, corresponding to previously published data. However, the mean TT-ratio in the group with conotruncal anomalies but without the 22q11.2 deletion was also smaller than that in controls, in contrast to previously published data. The TT-ratio was above the normal mean, regardless of fetal karyotype, in all cases of interrupted aortic arch. CONCLUSION: The TT-ratio method is a feasible and potentially useful tool during detailed fetal heart assessment. However, the absolute measurement is not reliable for prediction of 22q11.2 deletion and the obtained results should therefore be interpreted with caution. Fetal karyotyping should be recommended in cases with conotruncal heart abnormalities, irrespective of the TT-ratio.

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.

Three-dimensional fetal echocardiography for prediction of postnatal surgical approach in double outlet right ventricle: a pilot study.

OBJECTIVES: To examine the feasibility of reconstructing three-dimensional (3D) echocardiographic views in fetuses with double outlet right ventricle, which might enhance prognostication with respect to the postnatal surgical approach. METHODS: This was a retrospective blinded observational study. Our database was reviewed from January 2007 to June 2011 to identify fetuses with usual atrial arrangement, concordant atrioventricular connections, double outlet right ventricle and relatively balanced left and right ventricular size. Six fetuses, in which there was an intention to treat, were included. RESULTS: In all six cases, we identified important features, including location of the ventricular septal defect and its relation to the atrioventricular valves and great arteries. The postnatal surgical approach was predicted accurately in each case. CONCLUSION: In this group of fetuses with double outlet right ventricle, detailed evaluation by 3D fetal echocardiography enhanced visualization of the anatomy, leading to accurate prediction of the type of surgical repair. Prospective validation in a large cohort of fetuses is warranted.

Prenatally detectable congenital heart defects in fetuses with Down syndrome.

OBJECTIVE: To document the incidence of congenital heart defects (CHD) that are detectable echocardiographically in the fetus with trisomy 21 and the relationship with nuchal translucency, fetal sex and ethnicity. METHODS: Data on fetuses with a karyotypic diagnosis of trisomy 21 were collected between January 2002 and March 2010. The data were analyzed for the gestational age at examination, maternal age, reason for referral for fetal echocardiography, cardiac diagnosis, fetal sex, ethnicity and outcome. RESULTS: Of 917 fetuses with trisomy 21, 487 had a diagnostic echocardiogram. Cardiac examination was performed before 14 weeks' gestation in 75% of cases. The main reasons for referral were increased nuchal translucency (NT) in 76% of cases, suspected cardiac abnormality in 15% and an extracardiac anomaly in 6%. Structural CHD was found in 164/487 (34%), or 98/412 (24%) if those referred for suspected CHD are removed from the analysis. The most common diagnosis was atrioventricular septal defect (AVSD) (115/487, 24%). The ratio of female to male fetuses with AVSD was 29%:18% (P = 0.003). There was no difference in the incidence of AVSD with ethnicity. The pregnancy continued in 36 cases, but three were lost to follow-up; of the known outcomes there were 10 intrauterine deaths, six of which had structural heart disease, and 23 live births, 15 of which had CHD. CONCLUSION: Most fetuses (66-76%) with trisomy 21 have a structurally normal heart on echocardiography. The presence of structural CHD was not associated with increased NT. The increased incidence of AVSD in females was confirmed in our study, although an ethnic difference could not be confirmed. CHD does not appear to increase the chance of spontaneous intrauterine loss in ongoing pregnancies.

Aberrant right subclavian artery at 16 to 23 + 6 weeks of gestation: a marker for chromosomal abnormality.

OBJECTIVES: This study was carried out to determine the feasibility of defining the position of the right subclavian artery (RSA) by fetal echocardiography between 16 and 23 weeks of gestation, and the association between an aberrant right subclavian artery (ARSA) and chromosomal and cardiac defects. METHODS: We examined the position of the RSA in all patients who attended our unit for a fetal cardiac scan. The assessment was carried out using a transverse view of the fetal chest sweeping up from the level of the aortic arch, using color flow mapping. An ARSA was diagnosed when this vessel was not seen in the normal position and an arterial vessel was seen crossing behind the trachea towards the right arm, arising as a fourth branch of the aortic arch, at a lower level than normal. RESULTS: The course of the RSA could be identified in more than 95% of the 2799 fetuses examined between 16 and 23 + 6 weeks of gestation. An ARSA was found in 43 fetuses. The incidence was 1.5% in normal fetuses, 28.6% in fetuses with trisomy 21, 18.2% in fetuses with trisomy 18 and 8% in fetuses with other chromosomal defects. There was an association between an ARSA and cardiac defects in seven of the 43 fetuses (16%), and three of these seven fetuses had a normal karyotype. CONCLUSIONS: Assessment of the RSA by a fetal cardiologist is possible in almost all cases. The finding of an ARSA is much more common in fetuses with chromosomal defects, in particular trisomy 21 (where the prevalence of an ARSA was 29%), compared with euploid fetuses. Moreover, the presence of an ARSA may be associated with an increased incidence of intracardiac malformations. Examination of the position of the RSA is likely to become a routine ultrasound marker for chromosomal abnormalities in the second trimester of pregnancy.

Changing findings in pentalogy of Cantrell in fetal life.

Pentalogy of Cantrell is the association of five features: a midline anterior ventral wall defect, a diaphragmatic defect, a cleft distal sternum, a defect of the apical pericardium with communication into the peritoneum, and an intracardiac defect. This is a complex abnormality that requires multiple surgical procedures, but which can be successfully treated postnatally with staged surgery. Three recent cases demonstrated features in prenatal life that were unexpected to us, and which we felt were worthy of description. The diagnosis of the pentalogy of Cantrell was made at 11, 16 and 14 weeks. Two of the three had an increased nuchal translucency measurement. All three fetuses had a major abdominal wall defect with a significant degree of protrusion of the cardiac ventricles outside the chest at the initial scan. At 20 and 26 weeks, the heart was seen to be within the chest with no protrusion, even of the apex. An intracardiac malformation was found prenatally in two of three cases. There were no karyotype anomalies and all three cases survived despite multiple operations. At the time of writing they were aged 2, 5 and 8 years. The ultrasound findings in all three cases showed an evolving pattern during gestation, with a greater degree of protrusion of the heart through the lower sternal defect into the exomphalos in the early scans than was present later. The possibility of an improvement in the findings has some bearing on counseling in early pregnancy in this complex condition.

Tricuspid valve dysplasia or displacement in intrauterine life.

In 450 cases of structural heart disease diagnosed prenatally, 38 fetuses (8.5%) had either a dysplastic or a displaced tricuspid valve. The tricuspid valve was dysplastic in 22 fetuses, all of which had evidence of tricuspid regurgitation resulting in right atrial dilation and increased cardiothoracic ratio. An associated abnormality of the pulmonary valve occurred in 16 fetuses. The remaining 16 fetuses had Ebstein's malformation, 14 with evidence of tricuspid incompetence at presentation and 10 with an associated abnormality of the pulmonary valve. Of the 38 cases, the pregnancy was interrupted in 17, spontaneous intrauterine fetal death occurred in 8, 11 infants died postnatally and 2 infants are still alive; additional abnormalities were found in 8 cases (chromosomal anomalies in 2, ventricular septal defects in 2, corrected transposition in 2, the Chiari malformation in 2, supraventricular tachycardia in 1 case and coarctation of the aorta in 1). Fetuses with severe abnormalities are selected for fetal echocardiography by the four chamber screening program and a high rate of natural loss both in intrauterine life and immediately after birth was observed in the 21 cases in which pregnancy was continued. This would explain the higher incidence of tricuspid valve disease in our prenatal compared with postnatal series. Although increased cardiothoracic ratio and associated lesions of the right ventricular outflow tract contribute to the poor outcome in the cases detected prenatally, the absence of these features does not always indicate a good prognosis because progression of disease can occur with advancing gestational age. No absolute measurement or single echocardiographic feature emerged as a consistent predictive factor of prognosis.

Pulmonary atresia in prenatal life.

Seven cases of pulmonary atresia with intact ventricular septum were detected in prenatal life. In two of these cases, there was a small hypertrophied right ventricle of the type commonly seen postnatally. In the remaining five cases, the right atrium and right ventricle were grossly dilated to a degree that caused lung compression. The resulting impairment of lung development appeared to be an important factor contributing to death in all five cases. Decompression of the right ventricle by intrauterine surgery to allow normal lung development in the last weeks of pregnancy may be the only way of changing this outcome.

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.

Fetal echocardiography in trisomy 18.

BACKGROUND: Previously reported pathological series suggest that cardiac malformations are universal in trisomy 18. We examined our experience of fetal echocardiography in trisomy 18 for comparison. METHODS: Of 255 fetuses with trisomy 18 detected in our centre between January 1999 and June 2004, 174 were evaluated using fetal echocardiography. Our results were compared to four previous echocardiographic and four autopsy series, comprising 89 and 110 patients, respectively. RESULTS: Of these 174 fetuses, 114 were examined between 10 and 14 weeks gestation and the remainder between 15 and 33 weeks. An increased nuchal translucency measurement was the reason for referral in most of the early cases and extracardiac anomalies in the remainder. Images were non-diagnostic in 12 cases (7%), all examined at <15 weeks gestation. Abnormal cardiac findings were detected in 118 of the remaining 162 fetuses (73%), including 15 with functional anomalies. The various heart malformations included ventricular septal defects, tetralogy of Fallot, left heart disease, and atrioventricular septal defects. In all series used for comparison, a similar diversity of disease was seen. In pathological series of trisomy 18, structural heart malformations were found in all cases, but some had lesions which would not be detectable echocardiographically in the fetus. CONCLUSION: Abnormal cardiac findings are detectable echocardiographically in the majority of cases of trisomy 18 examined during fetal life, but not in all. A wide spectrum of heart defects is seen. Diagnosis of heart malformations can be made reliably, even in the first trimester at the time of nuchal translucency measurement.

Usefulness of preoperative echocardiography in predicting left ventricular outflow obstruction after primary repair of interrupted aortic arch with ventricular septal defect.

Residual left ventricular outflow tract (LVOT) obstruction is a significant problem after repair of interrupted aortic arch (IAA) and ventricular septal defect. Resection of subaortic tissue at the time of primary repair, however, is associated with increased morbidity and mortality. We reviewed the preoperative echocardiograms and the postoperative clinical course and echocardiograms of 23 consecutive patients who underwent primary repair of IAA without widening of the subaortic region. Nine patients (39%) developed significant LVOT obstruction (pressure gradient >40 mm Hg). LVOT obstruction was noted postoperatively in 7 of 9 patients by 1 month, 8 of 9 by 2 months, and 9 of 9 by 1 year. On retrospective analysis of the preoperative echocardiograms, the indexed cross-sectional area of the LVOT, the subaortic diameter index, and the subaortic diameter Z score were all significantly smaller in those requiring reintervention (p <0.04, p <0.05, p <0.05, respectively). Of these, indexed cross-sectional area had the least reproducibility and subaortic diameter index the most (coefficient of variation of 26.3% vs 11.2%). In conclusion, most patients who develop significant LVOT obstruction after repair of IAA do so within 1 month of operation. Although subaortic indexed cross-sectional area is the most sensitive predictor of LVOT obstruction after primary repair of IAA, other more simple standardized measurements of the subaortic diameter were comparably predictive and had better reproducibility.

Familial recurrence of congenital heart disease in a prospective series of mothers referred for fetal echocardiography.

Fetal echocardiography can ascertain, at an early stage in pregnancy, recurrences of congenital heart disease (CHD) in mothers with a family history of CHD. In 1,021 mothers referred for this reason, 20 recurrences were found; 17 occurred when there had been 1 previously affected child, and 3 when there had been 2 previously affected children. No recurrences were found in the 41 cases in which a parent had CHD. The overall recurrence rate was 1 in 52 with a previously affected child and 1 in 10 with 2 previously affected children. However, certain forms of CHD recurred much more frequently than others. Aortic valve atresia was associated with a recurrence rate of 1 in 28, coarctation of the aorta at a rate of 1 in 15, complex CHD at a rate of 1 in 11 and truncus arteriosus at 1 in 13. These findings are inconsistent with previous family studies; this may be due to more complete ascertainment, particularly of major lesions, possibly overlooked by postnatal family studies because of fetal loss. Alternatively, the availability of prenatal diagnosis may be producing an increase in family size after major CHD. The results support current doubts on the polygenic theory of inheritance for all forms of CHD.

World experience of percutaneous ultrasound-guided balloon valvuloplasty in human fetuses with severe aortic valve obstruction.

Prenatal alleviation of severe fetal aortic valve obstructions by percutaneous ultrasound-guided balloon valvuloplasty has been performed to improve the fate of affected fetuses. The purpose of this study was to analyze the current world experience of these procedures in human fetuses. Data from 12 human fetuses were available for analysis. The mean gestational age at intervention was 29.2 weeks (range 27 to 33). The mean time period between initial presentation and intervention was 3.3 weeks (range 3 days to 9 weeks). Technically successful balloon valvuloplasties were achieved in 7 fetuses, none of whom had an atretic valve. Only 1 of these fetuses remains alive today. Of the 5 remaining technical failures, 1 patient with severe aortic stenosis underwent successful postnatal intervention and remains alive. Six patients who survived prenatal intervention died from cardiac dysfunction or at surgery in the first days or weeks after delivery. Four fetuses died early within 24 hours after the procedure, 1 from a bleeding complication, 2 from persistent bradycardias, and 1 at valvotomy after emergency delivery. Thus, the early clinical experience of percutaneous ultrasound-guided fetal balloon valvuloplasty in human fetuses with severe aortic valve obstruction has been poor due to selection of severe cases, technical problems during the procedure, and high postnatal operative mortality in fetuses who survived gestation. Improved patient selection and technical modifications in interventional methods may hold promise to improve outcome in future cases.

Comparison of three-dimensional echocardiographic assessment of volume, mass, and function in children with functionally single left ventricles with two-dimensional echocardiography and magnetic resonance imaging.

Diminished systolic function or inappropriate hypertrophy are considered risk factors for outcome following the Fontan procedure. These parameters are difficult to assess in univentricular hearts that do not conform to the uniform shapes prescribed by conventional 2-dimensional imaging volume algorithms. Three-dimensional echocardiography requires no geometric assumptions and has been validated in both normal and distorted left ventricles. To assess the feasibility and accuracy of this technique in patients with univentricular hearts, we compared 2- and 3-dimensional echocardiographic estimates of ventricular volume, ejection fraction, and mass in patients with functionally single left ventricles with results obtained by magnetic resonance imaging (MRI). Twelve patients with functionally single left ventricles (6 months to 22 years) underwent examination by all 3 modalities. Correlation and agreement with MRI were calculated for volumes, ejection fraction, and mass. Three-dimensional echocardiographic comparison with MRI yielded a bias of 3.4 +/- 5.5 ml and 14.2 +/- 8.3 ml for systolic and diastolic volumes, respectively. Agreement analysis for mass showed a bias of 5.8 +/- 8.4 grams. Two-dimensional echocardiography showed less agreement for both volumes and mass (bias of -2.9 +/- 8.1, 2.9 +/- 10.4 ml and -8.3 +/- 12.0 g for volume and mass, respectively, p >0.05). Ejection fraction by 3-dimensional echocardiography showed significantly closer agreement with MRI (bias of 4.4 +/- 5.3%) than 2-dimensional echocardiography (bias of 8.5 +/- 10.3%, p = 0.04). Thus, 3-dimensional echocardiography provides estimates of ventricular volumes, ejection fraction, and mass that are comparable to MRI in this select group of patients with single ventricles of left ventricular morphology.

Fetal diagnosis of fatal congenital heart disease.

The identification of the structure of the fetal heart became possible in the early 1980s as the resolution of ultrasound equipment improved. At that time, use of fetal echocardiography was confined to mothers whose fetuses were at increased risk of developing congenital heart disease, although only 10% of congenital heart disease occurs in this group. In 1985 a French group suggested that obstetricians involved in routine scanning be taught a simplified form of heart scanning, which made it possible to screen the general pregnant population for major anomalies. This form of heart scanning involved the examination of one section of the heart, the four-chamber view, and this approach greatly increased the potential impact of fetal echocardiography. As a result of the success of this program in both the United Kingdom and France, a continually increasing proportion of major cardiac defects are detected prenatally. There is almost no form of structural heart disease seen in a four-chamber projection during a routine scan that will not result in the eventual death of the child or young adult. Surgery may delay or defer this event, depending on the anatomic anomaly, but in general the outlook for affected children and their chance of reaching healthy adult life is poor. Most parents who learn this before 20 weeks of pregnancy will elect to interrupt the pregnancy. As a result a decline in the number of postnatal cases of some defects, such as the hypoplastic left-heart syndrome, can be documented in postnatal life.

Histological changes in the left and right ventricle in hearts with Ebstein's malformation and tricuspid valvar dysplasia: A morphometric study of patients dying in the fetal and perinatal periods.

Both Ebstein's malformation and the related tricuspid valvar dysplasia are often associated with tricuspid regurgitation, and impaired right ventricular function may develop. Impaired function of the left ventricle in Ebstein's malformation has also been described. Interstitial fibrosis has been shown in the right and left ventricles of hearts with Ebstein's malformation from neonates, children, and adults. The objective of this study was to determine whether interstitial fibrosis seen in Ebstein's malformation is an intrinsic part of the congenital malformation or is acquired. From the fetal and perinatal periods, we compared 13 hearts with Ebstein's malformation (6 isolated and 7 with additional abnormalities) and 11 with tricuspid valvar dysplasia (3 isolated and 8 with additional abnormalities) with 16 controls. Three adult cases of isolated Ebstein's malformation in patients aged 17 to 20 years, were compared with 5 controls. The percentage of interstitial fibrous tissue and the thickness of the endocardium in the right and left ventricles were measured using histomorphometry. There were similar findings in Ebstein's malformation and tricuspid valvar dysplasia. Of 24 fetal and perinatal cases, 23 had normal interstitial fibrous tissue. Interstitial fibrosis was found in the right ventricle of only 1 perinatal heart with Ebstein's malformation and pulmonary stenosis. Of the 9 fetal cases, 4 had minimal right ventricular endocardial thickening (up to 10 µm). The left ventricular endocardium was normal in this group. Of the 6 perinatal cases with isolated Ebstein's malformation or tricuspid valvar dysplasia, 4 had right and 2 had left ventricular endocardial thickening (up to 345 µm). Of the 3 adult hearts with Ebstein's malformation, 2 had right ventricular endocardial thickening (47 and 225 µm) and 2 had right and 1 had left ventricular interstitial fibrosis. These results indicate that in both Ebstein's malformation and tricuspid valvar dysplasia the endocardial thickening develops in perinatal life, and in Ebstein's malformation the interstitial fibrosis develops in later life.

Outcome of isolated congenital complete heart block diagnosed in utero.

OBJECTIVE: To establish identifiable prenatal factors in fetal heart block which might predict death in utero, the need for intervention, or the probability of pacemaker requirement. SETTING: Tertiary referral unit for fetal echocardiography. SUBJECTS: 36 fetuses with congenital complete heart block and structurally normal hearts identified between 1980 and 1993. METHODS: Maternal anti-Ro antibody status was documented. Prenatal variables examined included absolute heart (ventricular) rate, change in rate, and development of hydrops fetalis. Postnatally, heart rate, need for pacing, and the indications for pacing were detailed. RESULTS: Of the total of 36 patients, there are 24 survivors; 11 are paced. Of those fetuses which died, two were electively aborted for severe hydrops, seven died in utero, two were immediate postnatal deaths, and one was an unrelated infant death. The trend was for the heart rate to decrease during fetal life and postnatally. Fetuses with deteriorating cardiac function did not always show the lowest heart rates. Bradycardia of less than 55 beats/min in early pregnancy or rapid decrease in heart rate prenatally were poor prognostic signs. Hydrops was also associated with bad outcome, 10 out of the 12 hydropic fetuses dying (83%). Of 10 fetuses presenting with a heart rate above 60/min, nine survived of whom three required pacing. Of seven presenting with heart rates of 50/min or less, only three survived and two of these required pacing. Of the two fetuses with negative maternal anti-Ro antibody status one died in utero and one required heart transplantation after pacemaker insertion. CONCLUSIONS: Isolated complete heart block identified in fetal life does not always have a good prognosis. An individual heart rate does not accurately predict the outcome in utero or the need for postnatal pacing. Regular, careful monitoring during pregnancy is required in order to optimise care and timing of any interventions.