PubMed Health⌕ Search

Biomedical subjects

L D Allan

Publications and source records attributed to L D Allan.

At least 19 recordsLinked to original sources
PubMed1992

Prognosis in fetal tetralogy of Fallot.

The outcome in a series of 23 cases of tetralogy of Fallot diagnosed prenatally was compared to published figures for this condition when (a) identified postnatally or (b) treated surgically. There was a marked difference in the survival between these groups, with the highest mortality (75%) occurring when the diagnosis had been made prenatally. The high incidence of chromosomal and extracardiac anomalies in this group (60%) largely accounted for the discrepancy. This, and the potential for progressive changes in the anatomy of the defect during pregnancy, must be taken into account by the pediatric cardiologist offering prognosis in early pregnancy.

Female↗
PubMed1992

Prognosis in fetal diaphragmatic hernia.

The reported mortality for prenatally detected congenital diaphragmatic hernia is high. Polyhydramnios and presentation in early pregnancy have been suggested as high-risk factors adversely affecting outcome. We retrospectively reviewed 55 cases of congenital diaphragmatic hernia diagnosed prenatally in our unit. There was an overall mortality of 73%. The mortality in cases with presentation before 25 weeks' gestation was 74%, if the cases resulting in termination of pregnancy are excluded, compared with a mortality of 60% in those seen after this gestational age. Underdevelopment of left-sided cardiac structures was found to be a helpful prognostic factor. We were unable to confirm the predictive nature of hydramnios. Associated chromosomal anomalies were found in two fetuses and major congenital heart disease in nine. Although diagnosis before 25 weeks' gestation is associated with a higher mortality than in cases detected later, it is not universally fatal. If congenital heart disease and chromosomal anomalies are excluded and there is little or no evidence of left heart underdevelopment, the odds for survival will improve. This should be taken into account when the management of these cases is planned.

Chromosome Aberrations↗
PubMed1992

Umbilical venous pressure in nonimmune hydrops fetalis: correlation with cardiac size.

OBJECTIVES: Our objectives were to examine the relationship between umbilical venous pressure and cardiac size in nonimmune hydrops fetalis and to assess the role of cardiac failure in the pathogenesis of the disease. STUDY DESIGN: Fourteen fetuses with nonimmune hydrops fetalis were investigated in a tertiary referral unit with high-resolution ultrasonography, echocardiography, and fetal blood sampling. Fetal heart size was assessed by measurement of the cardiothoracic ratio. Umbilical venous pressure was measured at the time of fetal blood sampling with a fluid-filled system. RESULTS: The 10 fetuses with elevated umbilical venous pressures had significantly increased cardiothoracic ratios (p = 0.02). These fetuses also had ascites. Four other fetuses had normal-sized hearts, normal umbilical venous pressures, and no ascites. There was a linear relationship between cardiothoracic ratio and umbilical venous pressure (r = 0.75, p = 0.003). CONCLUSION: Measurement of umbilical venous pressure validates cardiothoracic ratio as a noninvasive assessment of cardiac function in nonimmune hydrops.

Female↗
PubMed1992

Screening for congenital heart disease prenatally. Results of a 2 1/2-year study in the South East Thames Region.

OBJECTIVE: To assess the efficacy of four chamber view examination, during routine obstetric scanning, in the prenatal detection of fetuses with congenital heart disease. DESIGN: Prospective observational study. SETTING: Ten obstetric ultrasound units in the South East Thames Region. SUBJECTS: All pregnant women attending for routine obstetric ultrasound examination. INTERVENTION: Ultrasonographers performing routine ultrasound examinations were taught to obtain, and correctly interpret, the four chamber view of the fetal heart. When this view could not be achieved adequately, an attempt was made to identify a reason for failure and, if possible, to arrange a repeat scan. All suspected abnormalities were referred to a specialized unit. MAIN OUTCOME MEASURES: Numbers of true abnormalities detected or overlooked, and the number in whom abnormality was suspected incorrectly. RESULTS: Over a 2.5-year period, 69% of the known number of cardiac lesions associated with an abnormality of the four chamber view were detected prenatally during the routine obstetric scan, 10% were identified as a result of referal for other high-risk factors and 21% were overlooked. The overall positive predictive value in the 10 obstetric units was 36%. CONCLUSIONS: Prenatal screening for some forms of major congenital heart disease is possible by including examination of the four chamber view of the fetal heart in routine obstetric scans. However, there are important limiting factors that will influence the success of abnormality detection and must be taken into account if screening is to be effective nationwide.

Diagnostic Errors↗
PubMed1992

Cardiac tumours in intrauterine life.

Since 1980, 11 examples of cardiac tumour have been detected in the fetus out of a total of 794 congenital cardiac malformations. Patients were referred because of fetal hydrops in two, a family history of tuberous sclerosis in two, and because of the detection of a tumour mass during a scan at the local hospital in seven. The gestational age range at presentation was from 20-34 weeks. Of eight fetuses where death occurred, the histological type was rhabdomyoma in seven and teratoma in one. In seven cases, the lesion appeared single and in four there were multiple tumours. In two of the cases of rhabdomyoma, other family members had evidence of tuberous sclerosis. Termination of pregnancy took place in four cases; of seven continuing pregnancies, spontaneous intrauterine death occurred in four, and three children are still alive. Two of the three survivors has the clinical picture of tuberous sclerosis. The last case is as yet only 1 month old. In summary, even where the lesion is single, the most likely diagnosis in fetal cardiac tumour is rhabdomyoma, with associated tuberous sclerosis. However, the characteristic features of this latter condition may not become evident until some months after birth.

Echocardiography↗
PubMed1992

Potential impact of population screening for prenatal diagnosis of congenital heart disease.

The potential impact of prenatal screening for the detection of congenital heart disease (CHD) was assessed by prospective analysis of 428 consecutive infant admissions to a supraregional centre; 28 (6.5%) did not have CHD and were excluded from analysis. Of the 400 cases with CDH, 396 (99%) underwent fetal ultrasonography but scanning was performed only before 18 weeks' gestation in 200 (50%). One hundred and forty nine (37%) of all cardiac abnormalities and 149/283 (53%) of severe abnormalities were considered to be detectable prenatally in a screening echocardiographic four chamber view had this technique been used. Prenatal diagnosis of severe CHD actually occurred in only eight (2%) cases and was after 30 weeks' gestation in all. There were 181/347 (52%) of all mothers and 177/253 (70%) of the subgroup with severe abnormalities who expressed an opinion volunteered their preference for termination of pregnancy if mid-trimester diagnosis had been available. Mid-trimester detection of congenital heart disease rarely occurs at present despite fetal ultrasound scanning in almost all pregnancies. More than half of all severe congenital heart defects seen in infancy are potentially detectable by screening. Major training at primary scan level and modification of the timing of existing fetal anomaly scanning would be required for a screening programme to be effective.

Female↗
PubMed1992

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

OBJECTIVE: To evaluate a casting technique in the interpretation of fetal cardiac anatomy. DESIGN: In 32 fetuses, the echocardiographic and cast features were compared and correlated. PATIENTS: Three normal fetal heart specimens from spontaneous abortuses and 32 specimens from spontaneous or induced abortions with congenital heart malformation. RESULTS: There was close correlation between the echocardiographic and anatomical features in 32 abnormal fetuses studied. In some, additional features of diagnosis could be displayed on the cast and the relative sizes of the cardiac structures could be appreciated and defined. CONCLUSIONS: With increasing echocardiographic detection of congenital heart disease in early prenatal life, an increasing number of fetal heart specimens of small size are dissected for pathological confirmation. The use of silicone rubber casts to reproduce the internal anatomy proved a useful addition to dissection, providing a three dimensional model of the cardiac defect.

Autopsy↗
PubMed1992

Correlation between echocardiographic and morphological investigations of lesions of the tricuspid valve diagnosed during fetal life.

OBJECTIVE: To assess the degree of agreement between the fetal echocardiographic and postmortem examination of hearts from fetuses with severe malformations of the tricuspid valve. DESIGN: A retrospective study to analyse echocardiographic recordings and make comparisons with postmortem findings. SETTING: Tertiary referral centre for fetal echocardiography. Institute for cardiac morphology. PATIENTS: 19 cases shown to have severe malformation of the tricuspid valve by fetal echocardiography that died in the prenatal or neonatal period. MAIN OUTCOME MEASURES: Correlations between morphology and measurements made at echocardiography and necropsy. RESULTS: The echocardiographic diagnosis was Ebstein's malformation in seven and tricuspid valvar dysplasia in 12 fetuses. These findings were confirmed in six and eight cases at necropsy. In one false positive diagnosis of Ebstein's malformation, necropsy showed dysplasia of the leaflets of the tricuspid valve without displacement. In four cases with the echocardiographic diagnosis of valvar dysplasia, necropsy showed displacement, the hallmark of Ebstein's malformation. Associated malformations that are known to worsen prognosis were predicted correctly by echocardiography. Taking the mean duration of four weeks between echocardiographic and postmortem investigations, both methods showed cardiomegaly causing lung hypoplasia, right atrial dilatation, and relative hypoplasia of the pulmonary trunk, morphometric factors that may be responsible for the poor outcome. Mostly good agreement existed between the echocardiographic and postmortem measurements if cases with an interval of more than eight weeks between the measurements were excluded. CONCLUSION: Fetal echocardiography was proved to be a reliable technique in differentiating the variants of tricuspid valvar disease, in diagnosing associated cardiac lesions, and in predicting quantitative factors that can define the subsequent outcome.

Ebstein Anomaly↗
PubMed1991

Hypoplastic left heart syndrome: effects of fetal echocardiography on birth prevalence.

Hypoplastic left heart syndrome was diagnosed prenatally and confirmed in 105 fetuses since 1983 at a regional referral centre. An increased detection rate since 1988 is probably related to increased experience in the use of a four-chamber view of the fetal heart during routine obstetric ultrasound scanning. When the diagnosis was made sufficiently early, most parents chose to terminate the pregnancy after the prognosis and surgical options were explained. By contrast, after an increase in the mid 1980s, since 1988 there has been a striking fall in the number of newborn babies with hypoplastic left heart syndrome treated at a supraregional referral centre. More widespread use of four-chamber cardiac screening during routine fetal ultrasonography may reduce the number of newborn babies with hypoplastic left heart syndrome--a factor which should be taken into account when the likely requirements for neonatal cardiac transplantation facilities are calculated.

Abortion, Induced↗
PubMed1991

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.

Ebstein Anomaly↗
PubMed1991

Factors influencing the outcome of congenital heart disease detected prenatally.

The diagnosis of structural heart disease before birth is associated with a poor prognosis. Of 222 continuing pregnancies seen in a 10 year period, there has been a 79% mortality. This is inconsistent with published results and current concepts of the outcome for children with cardiac malformation. Of the 222, death occurred in intrauterine life in 57, 87 died as neonates, and 31 in infancy or childhood. There are 47 survivors of whom only five have survived beyond 4 years. Factors influencing the outcome in these cases were examined further. A high mortality was associated with the presence of extracardiac anomalies in 71 (32%) and prenatal cardiac failure in 28 (13%). As many patients were referred for these reasons, referral methods preferentially select patients with a different range of heart disease from that seen postnatally. In addition, some forms of heart disease progress in severity during fetal life. Those involved in the management and counselling after diagnosis of heart disease in early pregnancy must be aware of the additional prenatal factors influencing prognosis and allow for them in making predictions of outcome.

Child↗
PubMed1991

Flecainide in the treatment of fetal tachycardias.

Fourteen mothers were treated with flecainide for fetal atrial tachycardias associated with intrauterine cardiac failure. Twelve of the 14 fetuses responded by conversion to sinus rhythm. One of the 12 fetuses subsequently died in utero. The remaining fetuses suffered no morbidity and were alive and well 3 months to 2 years after delivery. The two fetuses in whom atrial tachycardia did not convert with flecainide were successfully treated with digoxin. These results compare favourably with previous forms of antiarrhythmic treatment. After recent reports of the side effects of flecainide treatment, however, it has been advised that this drug should be confined to high risk patients and those with life threatening arrhythmias. The use of flecainide for fetal arrhythmias should be limited to patients with severe fetal hydrops and supraventricular tachycardias. It should not be the first drug of choice in atrial flutter.

Cardiac Output, Low↗
PubMed1991

Left ventricular dysfunction in the fetus: relation to aortic valve anomalies and endocardial fibroelastosis.

OBJECTIVE: To examine the relation between a characteristic form of left ventricular dysfunction in the fetus and abnormalities of the aortic valve and endocardial fibroelastosis of the left ventricle. DESIGN: A retrospective study to examine the correlation between echocardiographic findings in the fetus and postnatal or necropsy findings. SETTING: Tertiary referral centre for fetal echocardiography. PATIENTS: Thirty fetuses showing a characteristic echocardiographic picture of left ventricular dysfunction. MAIN OUTCOME MEASURES: The relation between the prenatal echocardiographic features and the postnatal and necropsy findings. RESULTS: At presentation the size of the left ventricular cavity was normal or enlarged in all cases. The measurements of the orifice of the aortic root and mitral valve were either normal or small for the gestational age. The echocardiographic diagnosis made at presentation was critical aortic stenosis in all cases. At necropsy or postnatal examination the aortic valve was dysplastic and stenotic in 15 cases and the left ventricle had become hypoplastic in one of these. Aortic atresia was present in seven patients, three of whom had a hypoplastic left ventricle. In six patients the aortic valve was bicuspid although not obstructive. One of these patients had hypoplasia of the aortic arch and one had a hypoplastic left ventricle but in the remaining four patients endocardial fibroelastosis of the left ventricle was the only abnormality found. No follow up information was available in two. Of 26 patients for whom there was postmortem information, 24 had evidence of some degree of endocardial fibroelastosis of the left ventricle. Sequential observations showed that five cases developed into the hypoplastic left heart syndrome. CONCLUSIONS: This type of left ventricular dysfunction in the fetus is the result of an overlap of diseases, including primary left ventricular endocardial fibroelastosis, critical aortic stenosis, and the hypoplastic left heart syndrome.

Aortic Valve↗
PubMed1990

The use of colour Doppler in fetal echocardiography.

Doppler colour flow mapping provides a non-invasive method for studying patterns of blood flow in the cardiovascular system. We undertook a prospective study using this technique in order to document normal and abnormal patterns in the human fetus. A group of 50 consecutive normal fetuses were examined with colour flow mapping. Patterns of flow that could be readily identified in the majority included inflow at the atrioventricular valves, outflow through the arterial valves and flow in the aortic arch and arterial duct. Flow across the oval foramen and in the pulmonary veins was identified in approximately half the patients. Colour Doppler also proved helpful in the detection and definition of cardiac anomalies. A series of 74 cardiac malformations, seen during 1988, were examined with colour flow mapping. The presence or absence of flow across valves could be confirmed, valvar incompetence demonstrated and the direction of blood flow displayed across both normal and abnormal communications. Colour Doppler studies in the human fetus can thus improve the understanding of the characteristics of flow of blood and add to the accuracy of antenatal diagnosis of congenital heart disease.

Echocardiography, Doppler↗
PubMed1990

Structural cardiac abnormalities in the fetus: reliability of prenatal diagnosis and outcome.

The outcomes of 129 pregnancies in which the fetus was found to have a structural cardiac abnormality are reviewed. Over a 30-month period from January 1985 to June 1987, 1924 patients were referred to the British Heart Foundation Research Centre for Perinatal Cardiology at Guy's Hospital for fetal cardiac scanning. A total of 129 structural cardiac abnormalities was diagnosed; 53% of these patients were referred because of an abnormal 'four-chamber view' on ultrasound at the referring hospital; 47 of the pregnancies (69% of the 68 patients referred before 28 weeks) were terminated, and in the remaining 82 pregnancies outcome was poor with only 20 infants (16%) surviving longer than 11 months. The prenatal diagnosis was fully or partly correct in 96% of the 111 cases where it was possible to verify the diagnosis by post-mortem or postnatal diagnosis. In the 82 pregnancies not terminated, 13 of the 22 cases given a moderate or good prognosis survived more than 11 months (59% survival), but only seven of the 60 (12% survival) given a fatal, poor or uncertain prognosis. The benefits of a multidisciplinary approach are discussed.

Chromosome Aberrations↗
PubMed1990

Prenatal measurement of cardiothoracic ratio in evaluation of heart disease.

The cardiothoracic ratio was measured in 410 normal fetuses and in a group of 73 fetuses with functional or structural heart disease. In normal fetuses it was fairly constant throughout pregnancy, but of those with congenital heart disease it was raised in cases of Ebstein's anomaly, tricuspid dysplasia, atrioventricular septal defect, and complete heart block. In some forms of congenital heart disease, however, it was within the normal range. There was a significant positive correlation between the cardiothoracic ratio and fetal hydrops in the group of 15 fetuses with supraventricular tachycardias. In these fetuses the cardiac size decreased significantly once the fetus reverted to sinus rhythm after the mother had been treated. Measurement of the cardiothoracic ratio is essential in the evaluation of fetal hydrops, as an increased value may point to the diagnosis of an intermittent fetal tachycardia if the fetus is assessed during a period of sinus rhythm. The measurement of this index forms a part of the complete prenatal evaluation of structural heart disease. The degree of cardiomegaly may provide useful information about secondary lung compression or cardiac failure and therefore assist in giving an accurate prognosis for postnatal survival.

Female↗