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At least 163 records · Page 9Linked to original sources

The influence of coincidence of fetal and maternal QRS complexes on fetal heart rate reliability.

Bioelectrical fetal heart activity being recorded from maternal abdominal surface contains more information than mechanical heart activity measurement based on the Doppler ultrasound signals. However, it requires extraction of fetal electrocardiogram from abdominal signals where the maternal electrocardiogram is dominant. The simplest technique for maternal component suppression is a blanking procedure, which relies upon the replacement of maternal QRS complexes by isoline values. Although, in case of coincidence of fetal and maternal QRS complexes, it causes a loss of information on fetal heart activity. Its influence on determination of fetal heart rate and the variability analysis depends on the sensitivity of the heart-beat detector used. The sensitivity is defined as an ability to detect the incomplete fetal QRS complex. The aim of this work was to evaluate the influence of the maternal electrocardiogram suppression method used on the reliability of FHR signal being calculated.

Electrocardiography↗

Interpretation of the electronic fetal heart rate during labor.

Electronic fetal heart rate monitoring is commonly used to assess fetal well-being during labor. Although detection of fetal compromise is one benefit of fetal monitoring, there are also risks, including false-positive tests that may result in unnecessary surgical intervention. Since variable and inconsistent interpretation of fetal heart rate tracings may affect management, a systematic approach to interpreting the patterns is important. The fetal heart rate undergoes constant and minute adjustments in response to the fetal environment and stimuli. Fetal heart rate patterns are classified as reassuring, nonreassuring or ominous. Nonreassuring patterns such as fetal tachycardia, bradycardia and late decelerations with good short-term variability require intervention to rule out fetal acidosis. Ominous patterns require emergency intrauterine fetal resuscitation and immediate delivery. Differentiating between a reassuring and nonreassuring fetal heart rate pattern is the essence of accurate interpretation, which is essential to guide appropriate triage decisions.

Bradycardia↗

Antenatal fetal heart rate and "maternal intuition" as predictors of fetal sex.

OBJECTIVE: To determine if the antenatal fetal heart rate is a reliable predictor of fetal sex, if there is any correlation between "maternal intuition" and fetal gender, and if maternal intuition favors one sex over the other. STUDY DESIGN: Two hundred twelve consecutive maternity patients with singleton gestations underwent a total of 2,261 antepartum visits. Fetal heart rate assessment was carried out between 14 and 41 weeks of gestation. At 32 weeks, participants were asked if they had a strong intuitive feeling regarding the fetal gender. Following birth, data on the infant were recorded, and the information was analyzed. RESULTS: There was no significant difference in the baseline fetal heart rate between male and female fetuses at any recorded gestational age. One hundred ten patients (51.9%) in the sample indicated a strong belief about the sex of their fetuses, with the majority (63.6%) predicting a male. The accuracy of maternal intuition, however, was not significantly different from that of random guessing. CONCLUSION: In the current era of declining family size, an increased focus on absolute reproductive choice and proliferating reproductive technological services, prenatal sex determination and sex selection will continue to provoke increasing attention. Fetal heart rate determination and maternal intuition, however, are not valid predictors of fetal gender.

Adolescent↗

Electronic fetal heart rate monitoring with intrauterine fetal demise.

Management of patients during labor is often based upon interpretation of electronic fetal heart rate tracings. Misdiagnoses of these records can lead to inappropriate actions, including cesarean delivery for presumed fetal distress. This case study, using a heart rate tracing from a patient with intrauterine fetal death, describes the findings, reviews the origin of the electronic signal, and outlines the means to distinguish the fetal and maternal cardiac impulses.

Adolescent↗

Sinusoidal fetal heart rate pattern and severe fetal anemia.

This report describes a case of a sinusoidal fetal heart rate (FHR) pattern encountered in a fetus at 34 weeks' gestation during antepartum fetal stress testing because of maternal hypertension. Delivery of the fetus was accomplished, and the newborn was found to be severely anemic and hypotensive due to a massive fetomaternal transfusion. Some pathophysiologic mechanisms are suggested, and the clinical significance of this finding is discussed.

Adult↗

[Diagnosis of a fetal cardiac malformation. Fetal heart].

To diagnose a fetal heart abnormality is one of the most important purpose of the foetopathologic examination performed after spontaneous abortion, intrauterine death or pregnancy termination. Frequency of cardiac abnormalities in fetal or maternal pathologies explains the significance of this diagnosis in a pertinent genetic counseling before next pregnancy. The diagnose of a fetal heart abnormality requires a good knowledge of: normal anatomy and examination technics of fetal heart, congenital heart abnormalities classification and knowledge of the most common diagnosis, diagnostic orientation according to the cardiopathy: fetal origin in genic syndrome, chromosomal abnormalities, malformative or sporadic association; maternal etiology (toxic, infection, metabolic). This procedure needs experience, acquired by rigorous practice and team working.

Cardiomyopathies↗

[Effect of low molecular dextran on maternal microrheologic parameters, fetal heart rate and transcutaneous fetal oxygen partial pressure in labor].

The results from animal experimental research have shown that the infusion of dextran 40 increased the uterine blood flow mainly by decreasing the vascular resistance and by this improving the oxygen supply to the fetus. Dextran 40 given in a dosage of 50 ml/min within 10 minutes to 11 pregnant women during parturition showed that the fetal blood PO2 increased if the PO2 before infusion was low and decreased if the PO2 before infusion was high. Therefore the question enhanced if the reduced maternal oxygen capacity results in a reduction of fetal PO2 (tcPo2) too. After informed consent 10 healthy pregnant women at term with a normal pregnancy got an infusion of 500 ml dextran 40 during 30 minutes. The following maternal parameters were measured: heart rate, mean arterial blood pressure, intrauterine pressure and transcutaneous carbon dioxide tension (tcPCO2). Maternal microrheological parameters before and after infusion of dextran 40 were estimated as following: plasma viscosity, erythrocyte aggregation, serum osmolality, colloid osmotic pressure, hemoglobin and haematocrit. The mothers were laying in the side position and their ventilation was controlled by tcPco2 (Dräger, Lübeck). The following fetal parameters were registered: basal fetal heart rate, transcutaneous fetal oxygen partial pressure (tcPo2) and the umbilical cord blood gases. After rupture of the fetal membranes and at a cervix dilatation of about 5-7 cm a tcPo2 electrode (Dräger, Lübeck) was fixed at the fetal scalp with an acrylate glue (Histoacryl) and by this fetal tcPo2 and its "flow" registered.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗

Checkmark fetal heart rate pattern associated with severe fetal hypoxia. A case report.

A 31-year-old nulliparous woman developed vaginal bleeding after spontaneous rupture of the membranes at 40 weeks of gestation. Fetal heart rate monitoring showed checkmark and sinusoidal patterns. A 3,281 g male neonate was delivered by emergency cesarean section, with Apgar scores of 1 and 3 at 1 and 5 min, respectively. The neonate exhibited severe acidosis with arterial blood gas pH of 6.96, and was diagnosed to have severe hypoxic-ischemic encephalopathy. An umbilical artery branch was noted in the membrane near the cervical os and found to be torn, representing hemorrhagic vasa previa. Severe fetal hypoxia resulting from hemorrhagic vasa previa might be associated with checkmark fetal heart rate pattern.

Female↗

Diurnal rhythms in fetal heart rate baseline and sustained fetal tachycardia in twin pregnancy.

OBJECTIVE: To elucidate the synchronization of phases of diurnal rhythms in fetal heart rate (FHR) baseline between twin fetuses and the occurrence of sustained fetal tachycardia. METHODS: FHR was simultaneously recorded in twins for 24 h in 7 monochorionic diamniotic (MD) and 8 dichorionic diamniotic (DD) twin pregnancies at 35 to 38 weeks of gestation. The diurnal rhythms of the hourly mean FHR baseline were tested in each fetus, and the time of occurrence of sustained fetal tachycardia was compared between twins. The correlation coefficients and phase lags of diurnal rhythms between the hourly mean FHR baselines of twins were calculated in each case. RESULTS: There were significant diurnal rhythms in the hourly mean FHR baselines of all twin fetuses (p<0.01). The patterns of diurnal rhythms were similar for each pair of twins, with the exception of the periods of sustained fetal tachycardia. Sustained fetal tachycardia was not coincident between twins. Analysis in which the periods of sustained fetal tachycardia were excluded demonstrated a significant correlation between the hourly mean FHR baselines of twins in all cases (p<0.01). In the case of DD twins, the phase lag between twins was 0; however, phase lags were observed in 4 cases of MD twins. CONCLUSIONS: The results of this study revealed that the diurnal rhythms in the FHR baseline correlated well between twins, and that the occurrences of sustained fetal tachycardia were completely independent.

Adult↗

[Fetal heart rate accelerations and fetal oxygen pressure sub partu].

By means of tcPO2 measurement, a total of 297 FHR accelerations from 55 oxygen cardiotocograms were analysed with regard to their association with changes in fetal oxygen pressure sub partu. It could be demonstrated that the transcutaneous oxygen pressure of 2.3 kPa (17.1 mmHg) with occasional accelerations was significantly (alpha less than 0.05) higher than that of 2.2 kPa (16.6 mmHg) with periodic accelerations. Oxygen pressure with occasional accelerations with "classical parameters" (amplitude greater than or equal to 15 bpm, duration greater than or equal to 15 sec) did not significantly differ from that with one or both parameters below these minimal values. Furthermore, our results suggest the production of periodic accelerations by pressorreceptor reflex due to intermittent disturbance in umbilico-placental perfusion.

Blood Gas Monitoring, Transcutaneous↗

Automated analysis of antepartum fetal heart rate in relation to fetal rest-activity states: a longitudinal study of uncomplicated pregnancies using the Sonicaid System 8000.

OBJECTIVES: To learn which fetal heart rate (FHR) parameters change with gestational age and to demonstrate the relation with fetal rest-activity states. STUDY DESIGN: FHR and fetal movements were recorded in 12 uncomplicated pregnancies from 26 weeks gestational age onwards. Seventy-two FHR recordings of 60 min duration were analysed by a computer (Sonicaid System 8000). Statistical analysis of complete 60 min recordings and selective periods of rest and activity comprised Spearman's rank correlation test, regression analysis and Wilcoxon's signed-rank test. RESULTS: The time needed to meet the system's criteria of normality decreased with gestational age. The incidence of accelerations (ACC), overall FHR variation (VAR) and variation during 'episodes of high variation' (VEHV) increased with gestational age in the total population, but statistical significance of these relations could only be demonstrated in a minority of individual fetuses. Most FHR parameters differed significantly for periods of fetal rest and activity. No FHR parameters showed a relation with gestational age during periods of rest. CONCLUSIONS: The increase of ACC, VAR and VEHV with gestational age is primarily due to an increase during fetal activity. The considerable variation within and between fetuses, however, can only be partly explained by fetal rest-activity states.

Activity Cycles↗

The response of the fetal heart rate of amniocentesis.

Fetal heart rate monitoring during 107 amniocenteses suggested that acceleration of the fetal heart rate indicated fetal well-being. Eight out of the 19 fetuses who did not show this response (as against 2 out of the 88 others) had a low Apgar score at birth.

Adult↗

The indirectly obtained fetal heart rate: comparison of first- and second-generation electronic fetal monitors.

Fetal heart rate variability has become an essential component in evaluation of the fetus during continuous electronic fetal monitoring. Because of technical deficiencies of monitoring equipment, fetal heart rate variability may not always be available, such as during indirect monitoring of the fetus. In lieu of integration, a mathematical procedure called autocorrelation has, with the use of microprocessors, been incorporated into the fetal monitor, creating the "second generation" of electronic fetal monitoring. This study examined the accuracy of the first- and second-generation monitors by comparing simultaneously obtained indirect and direct real-time fetal heart rate data. The second-generation monitor produced an indirectly obtained fetal heart rate that was more accurate when compared with the directly obtained data than that with the first-generation fetal monitor. In addition, the variation in data from the first-generation monitor was substantially higher than that with the second-generation monitor. It is concluded that the fetal heart rate tracing from the second-generation monitor is more accurate when compared with the fetal electrocardiogram and may facilitate a truer interpretation of fetal heart rate variability than that obtained with the first-generation monitor.

Electrocardiography↗

Does a nonreactive fetal heart rate pattern really mean fetal distress?

The aim of the study was to compare three different fetal heart rate (FHR) patterns, namely, a nonreactive pattern with good long-term variability (fluctuation of 5 or more beats/min), a reactive pattern, and a nonreactive pattern with poor long-term variability (less than 5 beats/min). For this purpose, nonstress tests done less than 24 hours before delivery and FHR patterns recorded during labor were separately assessed. Endpoints for comparison were 5-minute Apgar scores, intrauterine growth retardation, and umbilical blood gas values at birth. Regarding the nonstress test, the prevalence of low 5-minute Apgar scores in reactive, good variability, and in poor variability patterns were 7.2%, 5.3%, and 24%, respectively. The prevalences of small for gestational age newborns were 8%, 17.6%, and 60.6%, respectively. Blood gas values did not differ significantly. Regarding the FHR patterns during labor, using the same sequence, the prevalences of low 5-minute Apgar scores were 3.5%, 6%, and 23%, respectively. Small for gestational age babies occurred in 8.8%, 15.6%, and 80% of the different FHR patterns, respectively. Regarding umbilical artery blood gas values, the only significant difference was a lower pH in the poor variability group. No difference was found between the blood gas values of babies with a reactive pattern and a nonreactive pattern with good variability.

Apgar Score↗

The clinical significance of the irregular fetal heart rhythm.

OBJECTIVE: Irregular fetal heart rhythms are common in clinical practice, but there is little information available on their significance or appropriate management. STUDY DESIGN: This was a retrospective review of fetuses seen during 10 years that either were referred for fetal echocardiography because of a fetal arrhythmia or were found incidentally to have an arrhythmia during fetal echocardiography for other indications. RESULTS: From 1988 through 1997 we performed 5566 fetal echocardiograms on 4838 different fetuses. There were 614 fetuses with irregular fetal heart rhythms. Among 595 referred for arrhythmias, extrasystoles were found in 255 (42.9%), normal rhythms were seen in 330 (55.4%), and hemodynamically significant arrhythmias were seen in 10. There were 2 fetuses with arrhythmias and structural heart disease. Nine of 10 fetuses with hemodynamically significant arrhythmias survived. An additional five neonates were found to have hemodynamically significant arrhythmias only postnatally. A total of 15 fetuses (2. 4%) among those referred for irregular rhythms had significant arrhythmias. CONCLUSIONS: Irregular fetal heart rhythms signify hemodynamically significant arrhythmias in a small but important proportion of fetuses. Those without persistent irregularities on evaluation can be followed up with routine prenatal care.

Arrhythmias, Cardiac↗

A comparison of methods for quantitating fetal heart rate variability.

Fetal heart rate (FHR) variability is thought to be an important index of fetal health. In the presence of normal variability, the fetus is vigorous, but lack of beat-to-beat variability may be associated with fetal compromise. A distinction between short-term variability (STV) (beat-to-beat changes between successive beats) and long-term variability (LTV) (rhythmic fluctuations in FHR) has not been made to date. We have utilized computer programs to compare three pairs of mathematical indices and one visual index of FHR variability. Among the three pairs of indices designed for detection of STV and LTV, de Haan's short-term and long-term indices exhibited the least interdependence, and the long-term index was completely insensitive to artifically generated pure STV. Yeh's short-term and long-term indices exhibited substantial positive interdependence. Hon's visual index appears to detect LTV primarily rather than STV. When the effect of progression of labor on FHR variability was examined, no conclusions were possible because of inconsistencies between patients. Ultimately, the clinical value of any one of these indices awaits testing of their ability to define fetal well-being or fetal distress.

Analog-Digital Conversion↗