Neurological morbidity after fetal supraventricular tachyarrhythmia.
(9/1926)
BACKGROUND: Fetal tachyarrhythmia is a well-documented entity which, in the absence of pharmacological intervention, may lead to congestive heart failure, fetal hydrops and eventually fetal demise. The success rate of the implemented treatment is generally measured by survival and achievement of control of the arrhythmia. We report on the occurrence of associated cerebral damage in three patients with fetal tachycardia. METHODS: We describe three patients with a history of fetal supraventricular tachyarrhythmia who developed cerebral complications in utero. RESULTS: Two patients had cerebral hypoxic-ischemic lesions and one had hemorrhagic lesions present at birth. They had developed severe congestive heart failure and fetal hydrops secondary to fetal tachyarrhythmia, and there were no other obvious causes for the cerebral pathology. Two of these patients were referred to us antenatally. Therapy was instituted and resulted in control of the tachycardia and resolution of hydrops. The third patient was referred to our clinic shortly after birth because of severe circulatory problems secondary to fetal tachyarrhythmia. CONCLUSION: From these observations, we believe that a fetus with tachyarrhythmia and subsequent hydrops is at increased risk for the development of cerebral complications, due to the circulatory disturbances and sudden changes in heart rate which may lead to fluctuations in cerebral perfusion. This would imply that it is of the utmost importance to aim at immediate and complete control of the heart rate in the treatment of fetal tachyarrhythmia. (+info)
Cardiac blood flow studies in fetuses with homozygous alpha-thalassemia-1 at 12-13 weeks of gestation.
(10/1926)
OBJECTIVE: Fetuses affected by homozygous alpha-thalassemia-1 develop anemia as early as the first trimester. Our objective was to study hemodynamic indices in affected fetuses at 12-13 weeks of gestation to determine whether these would be useful in the prediction of anemia. DESIGN: Prospective observational study. SUBJECTS: Women referred before 14 weeks of gestation for the prenatal diagnosis of homozygous alpha-thalassemia-1. METHODS: Transabdominal and/or transvaginal Doppler sonography was performed to measure the flow velocities in the fetal ascending aorta and pulmonary artery at 12-13 weeks. The Doppler indices were compared between those that were subsequently confirmed to be affected by homozygous alpha-thalassemia-1 and those that were unaffected. RESULTS: Between June 1997 and April 1998, 60 eligible women were recruited. Doppler examination was successful in 58 fetuses. Of these, 22 were subsequently confirmed to be affected by homozygous alpha-thalassemia-1. The diagnosis was made by chorionic villus sampling and DNA analysis in two affected fetuses and by cordocentesis and hemoglobin evaluation in 20 affected fetuses. Hemoglobin concentrations could be measured in ten fetuses and these ranged from 4 to 8 g/dl. The affected fetuses had significantly higher peak velocities at the pulmonary valve and ascending aorta and a larger inner diameter of the pulmonary valve than that in unaffected fetuses. The total cardiac output was increased by one-third in affected fetuses and was mainly due to an increase of the right-side cardiac output. CONCLUSION: In the early stage of anemia, the fetus responds mainly by increasing its right-side cardiac output. However, there is extensive overlap of the values of cardiac output between the affected and the unaffected fetuses, precluding its use in the prediction of anemia. (+info)
Validation of diameter measurements by ultrasound: intraobserver and interobserver variations assessed in vitro and in fetal sheep.
(11/1926)
OBJECTIVES: Blood flow evaluation in the fetus is hampered by inaccuracy in the measurement of vessel diameter. The impact of biological variation on reproducibility studies is unknown. The present study evaluated diameter measurements carried out with modern ultrasound equipment by assessing inter- and intraobserver variations. DESIGN: Repeated measurements analyzed by a general factorial model of analysis of variance. METHODS: Three observers measured repeatedly (six or more times for each tube and session) silicone tube implants (0.6, 2.2 and 6 mm), applying ultrasound imaging in eight fetal sheep, and the same silicone tubes in vitro. Analysis of variance was carried out on 199 observations made in vitro and 537 in vivo. RESULTS: The upper 95% confidence limit for the intra- and interobserver variations was higher for measurements made in vivo than in vitro. It was highest for the largest diameter and varied between 0.10 and 0.38 mm. When the diameter was determined as an average of repeated measurements, the error was reduced: six measurements in vivo had upper 95% confidence limits for intraobserver variation of 0.04 and 0.09 mm for diameters of 0.6 and 6 mm, respectively. CONCLUSIONS: The results show that ultrasound diameter measurements have a high reproducibility even for vessels of small dimensions when repeated measurements are taken with high-frequency ultrasound under favorable conditions. The low variation described in the present investigation of silicone tubes, compared to previous studies, suggests that diameter changes of living vessels represent a separate source of measurement variation. (+info)
Prenatal diagnosis of a lean umbilical cord: a simple marker for the fetus at risk of being small for gestational age at birth.
(12/1926)
OBJECTIVE: The purpose of this study was to investigate whether the prenatal diagnosis of a 'lean' umbilical cord in otherwise normal fetuses identifies fetuses at risk of being small for gestational age (SGA) at birth and of having distress in labor. The umbilical cord was defined as lean when its cross-sectional area on ultrasound examination was below the 10th centile for gestational age. METHOD: Pregnant women undergoing routine sonographic examination were included in the study. Inclusion criteria were gestational age greater than 20 weeks, intact membranes, and singleton gestation. The sonographic cross-sectional area of the umbilical cord was measured in a plane adjacent to the insertion into the fetal abdomen. Umbilical artery Doppler waveforms were recorded during fetal apnea and fetal anthropometric parameters were measured. RESULTS: During the study period, 860 patients met the inclusion criteria, of whom 3.6% delivered a SGA infant. The proportion of SGA infants was higher among fetuses who had a lean umbilical cord on ultrasound examination than among those with a normal umbilical cord (11.5% vs. 2.6%, p < 0.05). Fetuses with a lean cord had a risk 4.4-fold higher of being SGA at birth than those with a normal umbilical cord. After 25 weeks of gestation, this risk was 12.4 times higher when the umbilical cord was lean than when it was of normal size. The proportion of fetuses with meconium-stained amniotic fluid at delivery was higher among fetuses with a lean cord than among those with a normal umbilical cord (14.6% vs. 3.1%, p < 0.001). The proportion of infants who had a 5-min Apgar score < 7 was higher among those who had a lean cord than among those with normal umbilical cord (5.2% vs. 1.3%, p < 0.05). Considering only patients admitted in labor with intact membranes and who delivered an appropriate-for-gestational-age infant, the proportion of fetuses who had oligohydramnios at the time of delivery was higher among those who had a lean cord than among those with a normal umbilical cord (17.6% versus 1.3%, p < 0.01). CONCLUSION: We conclude that fetuses with a lean umbilical cord have an increased risk of being small for gestational age at birth and of having signs of distress at the time of delivery. (+info)
Fetal pulmonary venous flow into the left atrium relative to diastolic and systolic cardiac time intervals.
(13/1926)
OBJECTIVE: To establish the nature and gestational age dependency of the pulmonary venous flow velocity pattern into the left atrium relative to systolic and diastolic phases of the cardiac cycle. DESIGN: This was a cross-sectional study of Doppler measurements of fetal pulmonary venous inflow velocities, which were correlated with simultaneous recordings of transmitral and aortic flow velocity waveforms based on an equal cardiac cycle length (+/- 5%). RESULTS: Successful recordings were obtained in 28 out of 60 (47%) normal singleton pregnancies at 20-36 weeks of gestation. Reproducibility of waveform analysis of the various phases of the cardiac cycle was satisfactory, within-patient variance ranging between 1.7% and 6.5%. A statistically significant increase (p < 0.05) in pulmonary venous time average velocity and velocity integral with advancing gestational age was established. A statistically significant increase (p < 0.05) of the pulmonary flow velocity integral was also found when related to each of the systolic and diastolic segments of the cardiac cycle, with the exception of isovolemic relaxation time. The duration of each of the diastolic and systolic segments of the cardiac cycle, as well as the pulmonary venous velocity integral expressed as a percentage of the cardiac cycle, remained constant with advancing gestational age. CONCLUSIONS: The second half of pregnancy is characterized by pulmonary venous inflow into the left atrium throughout the cardiac cycle. Pulmonary venous inflow into the left atrium occurs predominantly during the filling and ejection phases of the cardiac cycle. Absolute cardiac diastolic and systolic time intervals as well as the percentage distribution of pulmonary venous flow velocity integrals between these cardiac time intervals remain unchanged with advancing gestational age. (+info)
Definitive diagnosis of intestinal volvulus in utero.
(14/1926)
Midgut volvulus with or without intestinal malrotation can occur in fetal life. Several reports have described congenital midgut volvulus showing non-specific sonographic findings of intestinal obstruction and perforation in utero. None of the previously reported cases, however, were definitively diagnosed as midgut volvulus by fetal sonography. We report two cases both exhibiting the sonographic 'whirlpool' sign, in utero. Color Doppler interrogation provided a clue to the viability of the involved intestinal segment. (+info)
Abnormal ductus venosus blood flow: a clue to umbilical cord complication.
(15/1926)
We report a case of umbilical cord complication causing, fetal hypoxemia and acidemia. At 30 weeks of gestation, the patient was referred because of slightly increased amniotic fluid volume and a non-reactive cardiotocogram. Biometry was appropriate for gestational age. Umbilical artery and fetal aortic Doppler findings were normal, whereas diastolic blood flow velocities in the middle cerebral artery were increased and the ductus venosus showed severely abnormal flow velocity waveforms with reversal of flow during atrial contraction. Since other reasons for fetal hypoxemia could be excluded, careful examination of the umbilical cord was performed. Traction of the hypercoiled umbilical cord due to its course around the fetal neck and shoulders was suspected. Cesarean section confirmed the sonographic findings and fetal blood gases revealed fetal acidemia. This case indicates that investigation of fetal venous blood flow may also help to identify fetal jeopardy due to reasons other than increased placental vascular resistance. (+info)
Dodecafluoropentane ultrasonic contrast enhancement in carotid diagnosis: preliminary results.
(16/1926)
To assess the efficacy in carotid diagnosis of an investigational dodecafluoropentane ultrasonic contrast enhancing agent, we compared B-mode, color flow, and duplex Doppler findings in 16 patients with common carotid artery bifurcation disease after dodecafluoropentane and saline injections. Dodecafluoropentane produced enhanced backscatter in all patients for 4 to 20 min (mean, 8.4+/-4.74 min) after intravenous injection. In six patients this enhancement improved the color flow and pulsed Doppler signal detection in areas of sonographic shadowing. The enhanced color flow information changed the diagnostic impression in one case. Dodecafluoropentane produced enhanced backscatter in the carotid artery in all patients, and for a mean duration longer than that reported for other agents. It has the potential to improve the efficacy of carotid ultrasonic evaluation. (+info)