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L D Allan

Publications and source records attributed to L D Allan.

At least 91 records · Page 5Linked to original sources
PubMed1987

Doppler echocardiographic evaluation of the normal human fetal heart.

Pulsed wave Doppler estimates of blood flow velocity were made across the mitral, tricuspid, aortic, and pulmonary valves in a series of 120 normal fetuses (gestational age 16-36 weeks). In 36 of these the data were obtained in all four sites. The maximum and mean velocities were calculated for each valve and these values were plotted against gestational age. There was little change in these values throughout pregnancy. The orifice dimensions of the valves were measured by cross sectional echocardiography. At all ages the tricuspid orifice was larger than the mitral and the pulmonary orifice was larger than the aortic. The blood flow values for each valve were derived from the product of the mean velocity and the valve orifice dimensions. The output of the right ventricle was usually, but not always, greater than that of the left ventricle. Combined ventricular output increased from approximately 50 ml/min at 18 weeks to 1200 ml/min at term. Despite limitations in the accuracy of the technique these results form a useful basis for the analysis of blood flow in the normal fetus and for the interpretation of abnormal Doppler findings in prenatal life.

Aortic Valve↗
PubMed1987

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

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

Aorta↗
PubMed1986

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.

Aortic Coarctation↗
PubMed1986

Prenatal screening for congenital heart disease.

Routine ultrasound examination of the fetus is already established in most obstetric units in Britain. A simple method was devised to evaluate one section of the fetal heart systematically. Examination of this section, the four chamber view, may readily be incorporated into routine obstetric screening. Severe cardiac abnormalities detectable in this view occur in two per 1000 pregnancies. For six years the department of paediatric cardiology at Guy's Hospital, London, served as a referral centre for fetal echocardiography. As teaching became more widespread an increasing proportion of cases of cardiac anomaly were referred because the obstetrician suspected abnormality on examination of the four chamber view. Currently 80% of detected abnormalities are referred for this reason. Further extension and organisation of teaching might result in most severe cardiac malformations being detected in early prenatal life.

Female↗
PubMed1986

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.

Cardiomegaly↗
PubMed1986

Aetiology of non-immune hydrops: the value of echocardiography.

Forty-eight pregnancies, five of them multiple, were referred for fetal cardiac assessment following the detection of non-immune hydrops fetalis; there were 52 hydropic fetuses in total. A cardiovascular aetiology was found in 21 of these 52 (40%); structural heart disease was present in 13, tachyarrhythmia in the remaining eight. The accurate delineation of these causes was possible using fetal echocardiography, and enabled rational management to be instituted. This included termination of pregnancy, pharmacological control of arrhythmias and appropriate timing of delivery.

Echocardiography↗
PubMed1985

Echocardiography in the investigation of anterior abdominal wall defects in the fetus.

Of 20 pregnancies referred for fetal echocardiography with a diagnosis of anterior abdominal wall defect, congenital heart disease was present in eight of the 17 with exomphalos and in none of the three with gastroschisis. Four of these eight affected pregnancies were terminated because trisomy 18 was diagnosed, of the remaining four, only one baby survived infancy. We conclude that ultrasound investigation of the fetal heart is an important part of the diagnostic assessment of anterior abdominal wall defect if an accurate prognosis and appropriate obstetric management are to be provided.

Abdominal Muscles↗
PubMed1984

Evaluation and treatment of fetal arrhythmias.

In a series of 31 cases referred for the evaluation of fetal arrhythmia, it was possible to identify the rhythm disturbance correctly using M-mode echocardiography. Cross-sectional echocardiography delineated structural abnormality where it occurred in association with an arrhythmia. Fifteen cases had premature atrial or ventricular contractions occurring in structurally normal hearts. These were not associated with perinatal mortality or morbidity in our series. Nine cases had complete heart block, three of which had structural cardiac anomalies. Seven cases were of atrial tachycardia, six were treated prenatally, one was delivered prematurely. Correct identification of an arrhythmia and appropriate prenatal therapy where indicated, was found to prevent unnecessary operative or premature deliveries.

Arrhythmias, Cardiac↗
PubMed1984

Balloon atrial septostomy in the neonatal intensive care unit.

In eight infants with complete transposition of the great arteries balloon atrial septostomy was performed in the neonatal intensive care unit solely under cross sectional echocardiographic control. One infant developed necrotising enterocolitis; otherwise there were no complications. This technique eliminates the need for radiographic screening during the procedure, is quick, and causes little disturbance to the infant who does not have to be removed from the incubator.

Echocardiography↗
PubMed1984

Evolution of coarctation of the aorta in intrauterine life.

The echocardiographic appearances in a case of coarctation of the aorta, first suspected at 21 weeks of intrauterine life, changed progressively during this time. Early right ventricular hypertrophy and increasing aortic arch hypoplasia were evident and suggest the possible sequence of evolution of the coarctation in this case.

Aortic Coarctation↗
PubMed1984

Echocardiographic and anatomical correlations in fetal congenital heart disease.

In a series of 1600 pregnancies 34 cases of congenital heart disease were correctly identified by fetal echocardiography. In each case echocardiographic diagnosis was confirmed by anatomical study. Termination of pregnancy was done electively in 14 cases: in six because of the identification of a cardiac anomaly and in the remaining eight because of multiple congenital anomalies. The remaining 20 fetuses died subsequently owing either to the complexity of congenital heart disease or to associated extracardiac abnormalities, which were present in more than half the fetuses with congenital heart disease. There were eight errors in interpretation of the fetal echocardiogram. The outcome of the pregnancy was not influenced by the error in any case. Fetal echocardiography can predict correctly structural malformations of the heart. The technique is sufficiently reliable to give an accurate prognosis in early pregnancy and provide the basis for alterations in obstetric management.

Diagnostic Errors↗
PubMed1983

Evaluation of fetal arrhythmias by echocardiography.

The normal fetal heart shows variation in rate and rhythm. Twenty three cases that fell outside the normal patterns of variation of heart rate and rhythm were evaluated by echocardiography. Ten showed atrial or ventricular extrasystoles and these were not associated with perinatal morbidity or mortality. Seven cases showed complete heart block, two in association with structural cardiac abnormality. Six cases were of supraventricular tachycardia, five of which were successfully treated and one was delivered prematurely. It was possible to diagnose accurately the type of arrhythmia using the M-mode echocardiogram to compare the relation between atrial and ventricular contraction. Cross-sectional echocardiography allowed identification of associated structural abnormalities. Recognition that an arrhythmia is present and appropriate prenatal treatment if this is indicated will avoid unnecessary operative or premature deliveries.

Arrhythmias, Cardiac↗