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PubMed1989

[Effects of hemodialysis on left ventricular performance: a Doppler echocardiographic study].

Left ventricular systolic and diastolic performance was examined using Doppler and M-mode echocardiography in 42 patients with chronic renal failure before and after hemodialysis. Twenty patients with left ventricular hypertrophy, 22 without hypertrophy and 30 normal subjects were studied. Chronic renal failure patients showed significantly larger chamber diameters of the left ventricle, left atrium and right ventricle than did normal subjects. This group also exhibited greater fractional shortening, stroke volume and cardiac output. Before hemodialysis, patients with left ventricular hypertrophy had a significantly higher cardiac output and the greater ratio of late to early diastolic peak flow velocities (A/R) than did patients without hypertrophy. After hemodialysis, there were significant reductions in blood pressure, ventricular and atrial dimensions, stroke volume and cardiac output. The velocities of early and late diastolic left ventricular filling and the deceleration rate were also significantly reduced. The heart rate, A/R, deceleration half time, and the ratio of deceleration half time to acceleration half time (DHT/AHT) were significantly increased. The greater the amount of fluid removed, the greater the changes in the above values. Patients with left ventricular hypertrophy exhibited significant reductions in fractional shortening, ejection fraction, stroke volume and cardiac output, compared to those without hypertrophy. However, patients without hypertrophy showed more significant decrease in the acceleration half time and increase in DHT/AHT than did patients with hypertrophy. These findings demonstrated normal systolic function and impaired diastolic properties in patients with chronic renal failure, who had left ventricular hypertrophy unaccompanied by dilatation.

Adult↗
PubMedDate not supplied

[Stimulating effect of pancreatic DNase on Bacillus subtilis growth as a function of the physiologic properties of the inoculation culture].

The stimulating effect of pancreatic DNAse on Bacillus subtilis growth was studied in relation to the content of "slowly growing" cells in the inoculation culture in the phase of decelerated growth. Three cell fractions of B. subtilis were obtained using the stepwise separation of the population in terms of buoyant density in the phase of decelerated growth. In contrast to fractions II and III, fraction I contained cells with decelerated growth, competent, permeable to exogenous DNAase I, and sensitive to the action of this enzyme. The faster growth of bacterial cells in fraction I was shown to be associated with the shorter lag period of these cells having a longer generation time.

Bacillus subtilis↗
PubMedDate not supplied

[Diagnosis of constrictive pericarditis and restrictive cardiomyopathy by pulsed Doppler echocardiography].

Characteristics of flow through atrioventricular valves were analyzed by pulsed Doppler echocardiography (PDE) in 7 patients with either constrictive pericarditis or restrictive cardiomyopathy and 10 controls to determine the value of this technique in their differentiation. All patients were admitted with systemic venous congestion and underwent right and left heart catheterization. PDE variables considered included peak flow velocity (PV), acceleration time, peak velocity of the atrial component (PVA), PVA/PV quotient, duration of early diastolic fillings, deceleration of early diastolic filling, duration of diastolic flow and mean temporal velocity. Ventricular filling differed between patients and controls in that the former group was characterized by higher PV's, lower PVA's, higher deceleration and lower PVA/PV quotient. When we compared both patient groups we found a significant tendency toward higher PV's, faster deceleration and lower PVA/PV quotient in constrictive pericarditis.

Adult↗
PubMed1986

[Development of gait in children--characteristics of gait in children from the viewpoint of ground reaction force].

Walking patterns of fifty-seven normal children were studied using large-sized force plates and compared with those of normal adults. In the vertical component of the ground reaction force, the peak of the deceleration phase was higher than that of the acceleration phase in younger children. In the sagittal component, the peak of the deceleration phase was higher than that of the acceleration phase, particularly in younger children. The point of change from the deceleration phase to the acceleration phase appeared earlier than that of adults. The lateral component in younger children was relatively larger than that of the older children and adults. The period of change from the child walking pattern to the adult walking pattern in each component was as follows:--In the sagittal component it was about five years of age, in the vertical component at about six years of age and in the lateral component at about nine years of age.

Adult↗
PubMed1987

Infant visual sustained attention and respiratory sinus arrhythmia.

Infants were studied cross-sectionally at 14, 20, and 26 weeks of age. They were presented with varying and complex patterns on a TV screen. Two-thirds of the presentations were accompanied by an "interrupting stimulus" in the periphery delayed in time from the onset of fixation on the central stimulus. The infants were not easily distracted from looking at the central stimulus when the presentation of the interrupting stimulus occurred at the point of maximal heart rate (HR) deceleration. However, if the presentation occurred at the end of the HR response, the infants were easily distracted. Infants with large amounts of respiratory sinus arrhythmia (RSA; i.e., HR variability) in a baseline recording were less distractible during the deceleration-defined trials than were infants with low amounts of RSA. High-RSA infants also showed larger HR deceleration on these trials than did the low-RSA infants. These results are consistent with a model positing that sustained HR lowering during visual fixation is an index of active attention and that RSA is an index of voluntary, sustained attention in infants.

Arrhythmia, Sinus↗
PubMed1985

[Effect of calcium antagonist (diltiazem) on left ventricular diastolic properties in essential hypertension: a pulsed Doppler echocardiographic study].

To evaluate the acute effect of diltiazem on left ventricular diastolic properties, we measured transmitral flow in 15 patients with essential hypertension using pulsed Doppler techniques. Before administering diltiazem, the peak velocity (R) and the deceleration rate of rapid inflow decreased significantly as compared with healthy subjects, but the peak velocity during atrial contraction (A) and the A/R increased significantly. Immediately after the intravenous administration of 10 mg diltiazem, blood pressure decreased from 157 +/- 22/96 +/- 12 mmHg to 135 +/- 19/82 +/- 11 mmHg (p less than 0.001) and the heart rate increased from 69 +/- 10/min to 74 +/- 10/min (p less than 0.05). However, 30 minutes after the injection, these returned to control values. The peak velocity and deceleration rate of rapid inflow were 52 +/- 9 cm/sec and 227 +/- 65 cm/sec2, respectively, before administering diltiazem, and five minutes after injection, these parameters increased to 63 +/- 13 cm/sec (p less than 0.001) and 292 +/- 82 cm/sec2 (p less than 0.001), respectively. Thirty minutes later, these values leveled off at 58 +/- 12 cm/sec (p less than 0.01) and 257 +/- 76 cm/sec2 (p less than 0.05), respectively. The peak velocity during atrial contraction was 67 +/- 12 cm/sec before administration, and this did not change significantly after injecting diltiazem. Significant increases in peak velocity and deceleration rate of rapid inflow and decreases in the A/R continued after the blood pressure and heart rate returned to control values. It was therefore concluded that diltiazem improves impaired early diastolic left ventricular filling in essential hypertension.

Adult↗
PubMed1986

Fetal cardiac asystole during labor.

A review of 14 cases of fetal cardiac asystole greater than two seconds during labor revealed two distinct patterns. Type 1 episodes developed without warning in eight apparently healthy fetuses at the nadir of a variable deceleration. These episodes were both preceded and followed by normal to increased variability, stable baseline heart rate, and less dramatic variable decelerations. Analysis of the fetal electrocardiogram (ECG) complexes during the asystole revealed a normal QRS complex, either biphasic or absent P-waves, and occasional ventricular extrasystoles. One of eight fetuses in this group died; the remainder were delivered in good condition and required minimal resuscitation. The mechanism of type 1 episodes appears to be an exuberant vagal response to umbilical cord compression. Rapid intervention probably is not warranted. Type 2 episodes developed in seriously asphyxiated infants and frequently were preceded by absent variability and, usually, severe decelerations. The fetal ECG pattern during the episode revealed bradycardia with sinus rhythm. Five of the six infants with type 2 episodes died either in utero or in the neonatal period. Despite the ominous portent of type 2 patterns, rapid delivery appears to be indicated.

Birth Weight↗
PubMed1985

Supine position in labor and associated fetal heart rate changes.

Presented is an investigation of the relationship of fetal heart rate (FHR) deceleration and position of the patient in labor. In a group of 902 laboring patients, 126 (14%) demonstrated late decelerations. Of the 126, 24 (19%) patients demonstrated late decelerations in the supine position only. These occurred during uterine contractions and were associated with reduced femoral arterial blood pressure and amplitude of the capillary pulse of the big toe. A drop in capillary blood pH of the fetal scalp could also be demonstrated. These effects reproducibly appeared and disappeared when supine and lateral positions were alternated. These data would suggest that maternal aortic compression by the pregnant uterus plays a role in the etiology of fetal stress as expressed by changes in fetal heart rate and acid base balance. This effect can be evaluated and monitored simply by recording the pulse pressure of the big toe and femoral arterial pressure. These atraumatic procedures can be applied to any patient.

Aorta, Abdominal↗
PubMed1985

Repetitive reduction of uterine blood flow and its influence on fetal transcutaneous PO2 and cardiovascular variables.

The influence of repeated asphyxia on fetal transcutaneous PO2, relative local skin perfusion, heart rate, blood gases and pH was investigated in 15 experiments on 8 acutely instrumented sheep fetuses in utero between 125 and 145 days gestation (term is 147 days). Uterine blood flow was intermittently arrested (11 times within 33 min) by intra-vascular maternal aortic occlusion, exposing the fetuses to repeated episodes of asphyxia of 30 (n = 3), 60 (n = 9) and 90 (n = 3) s duration. The fetal transcutaneous PO2 fell as the duration of asphyxia (2 alpha less than 0.01), heart rate deceleration area (2 alpha less than 0.01) and acidaemia (2 alpha less than 0.01) increased. With decreasing skin perfusion, which was dependent on the duration of asphyxia (2 alpha less than 0.001) and acidaemia (2 alpha less than 0.001), a discrepancy developed between transcutaneous and arterial PO2. The increase (delta) in transcutaneous-arterial PO2 difference was related linearly to the duration of asphyxia (2 alpha less than 0.01), the mean haemoglobin oxygen saturation (2 alpha less than 0.001), acidaemia (2 alpha less than 0.001) and relative local skin flow (2 alpha less than 0.05). It was highest after severe episodes of asphyxia (90 s), when O2 saturation, skin blood flow and arterial blood pH values were low. Fetal heart rate deceleration area was only correlated with the cutaneous-arterial PO2 difference when the mean fetal haemoglobin oxygen saturation was below 35%. Thus, a discrimination of heart rate decelerations that are significant for the fetus seems to be possible, when associated with low transcutaneous PO2 values. We conclude that in the sheep fetus transcutaneous PO2 measurements during repeated asphyxial episodes yield information on fetal oxygenation and on the skin vasomotor response.

Acid-Base Equilibrium↗
PubMed1979

[Conformational changes in the heat-denatured nucleotide complex of human lymphocytes on subsequent cooling].

The microfluorometric technique allowed an assay of the chromatin state from binding of acridine orange in studies on the kinetics of conformational changes in the nucleoprotein complex (NP) of human peripheral blood lymphocytes. Extraction of F1 histone fraction with 0.01 N HCl (pH 2) substantially altered (decelerated) conformational changes in the NP complex. Extraction of F1, F2 and F3 histone fractions with 0.25N HCl (pH 0.6) led to a more pronounced deceleration of the kinetics of conformational changes. The latter ones were decelerated as well when the process was run in a more viscous medium (e. g. in a 70% glycerin solution). No conformational changes in the NP complex deproteinized with 0.25N HCl were revealed in a vicsous medium. In such a case the NP complex showed low F530 values and elevated values of the alpha coefficient that seems likely to suggest the nonreversible denaturation of the NP complex.

Cell Nucleus↗
PubMed1978

[Cardiorespirography in physiologic and pathologic premature infants].

The cardiorespirography investigation, carried out in 42 premature newborn has led to the following results: 1. The narrowed undulatory zone was stated more frequently in cases of prematurely born infants, than in those of mature ones.--2. A silent zone was a typical phenomen with pathological prematurely born infants. The silent zone of type b together with tachypnoe and apnoic attacks and decelerations, prevailed within the group of infants suffering from IRDS. A typical silent zone of type a together with bradycardia, bradypnoe and apnoic attacks without decelerations was found in infants with the symptoms of intracranial haemorrhage. There were observed the silent zone of type a and of type b in cases of severe neonatal infections. But apnoic attacks with decelerations proved to be more frequent than in cases suffering from IRDS and intracranial haemorrhage. The respiratory curves showed an accentuated respiratory periodicity.--3. Whereas in cases of infants with IRDS the correction of the acid base balance brought about the correction of CRG--a gradual passage from the silent zone of type b to the undulatory one, the correction of the acid base balance did not bring about any change in the type of the silent zone within the group of cases of infants suffering from intracranial haemorrhage.--4. The cardiorespirography would therefore be suitable to be used, in relation to acid base balance values, as an additional method of establishing differential diagnosis in neonatal pathological cases.

Acid-Base Equilibrium↗
PubMed1978

Mathematical modeling of the head and neck response to -Gx impact accelration (minimum articulation requirements).

Data on the dynamic response of the living human head and neck to -Gx impact acceleration was analyzed. The Calspan 3-D Computer Simulator of a Motor Vehicle Crash Victim was used to provide estimates of the head and neck response to be expected for the very specific deceleration profiles simulated. Two segments connected via a pivot were used to represent the head-neck system. The monitored T1 deceleration profile was used to drive this system and the simulation head-neck response was checked for accuracy in replicating motional characteristics and trends in the response mechanism. Two head pivot locations were considered. The first was the occipital condylar point and the second was a theorized hingepoint in the head which minimized the distance from this point to the T1 anatomical coordinate system over the range of body orientations observed in the photographic data. For the two geometrical representations, a successive approximation technique was employed to analyze the resulting data. This approach initially removed all constraints to head and neck motion, and the resulting simulation results were compared to the human data. Restrictions to head and neck motion were then successively added until an adequate replication of the human data was obtained. This approach made it possible to correlate specific events, such as loading of the head-to-neck dorsiflexion limiting angle, to head deceleration profile characteristics. Results were compared to calculations obtained for eight additional subjects and proved to be in good agreement.

Acceleration↗
PubMed1984

Fetal cardiac responding: a correlate of birth weight and neonatal behavior.

Certain intrapartum fetal heart-rate (FHR) patterns are associated with low Apgar scores and other neonatal risks. Intrapartum FHR has been the subject of extensive clinical investigation, but only occasional reference is made to the possible behavioral correlates of this phenomenon. The current investigation found that neonates classified as FHR decelerators had lower birth weights and shorter gestational ages than FHR accelerators. Decelerators exhibited higher baseline heart rate and experienced more frequent uterine contractions than accelerators. Neurobehavioral assessment of these neonates indicated that decelerators had more abnormal reflex ratings and were less behaviorally organized than heart-rate accelerators. The results indicate that FHR responses are associated with prenatal growth, maturity, and possibly stress tolerance, and that intrapartum FHR responses be related to nonoptimal neonatal behavior.

Behavior↗
PubMedDate not supplied

[Disorders of the fetal oxygen supply during labor--retrospect and prospect of diagnostic possibilities].

Uterine blood flow decreases during uterine contractions. Under physiological conditions there is however an uterine hemodynamic buffer mechanism to guarantee a sufficient oxygen supply to the fetus even during uterine contractions. Heart rate decelerations occur therefore not during the period of cervical dilation but in the second stage of labor. In disorders of pregnancy uterine blood flow is primarily reduced and the slightest uterine contraction exhibits signs of fetal hypoxia, i.e. deceleration of fetal heart rate. Heart rate decelerations signify the possibility of the deterioration of the fetal acid base status. But the degree of fetal acidosis can be estimated only by fetal scalp blood sampling. A valuable tool to predict fetal hazard is to measure the transcutaneous PO2. Numerous hypoxic episodes decrease not only the arterial PO2 but also the skin blood flow which demonstrates a reduced peripheral circulation. This, however, is an indication of severe fetal stress in utero.

Acid-Base Equilibrium↗
PubMed1984

Antepartum fetal heart rate pattern associated with major congenital malformations.

Antenatal fetal heart rate monitoring of 20 fetuses with major congenital malformations revealed loss of long-term variability in 11 (55%) and an isolated, abrupt-onset fetal heart rate deceleration in 13 (65%). In ten (50%), loss of variability coexisted with periodic fetal heart rate decelerations. These fetal heart rate changes were significantly more prevalent in the malformed group than in a control population. There was also a significantly increased incidence of fetal distress in labor and in the requirement for primary cesarean section delivery. Perinatal mortality was 75%, reflecting the lethal nature of the malformations. Loss of long-term fetal heart rate variability associated with isolated, abrupt occurrence of fetal heart rate deceleration should raise the possibility of congenital malformations in an apparently normal pregnancy.

Abnormalities, Multiple↗
PubMed1984

[A scoring system for the evaluation of prenatal cardiotocograms: a study on normal patients].

A 10-point scoring system based on the basal heart rate, amplitude and frequency of variation, accelerations and decelerations was developed to assess antenatal fetal heart rate patterns in 47 patients with uncomplicated pregnancies and deliveries. From a gestational age of 28 weeks the fetal heart rate was monitored every 2 weeks until 36 weeks and then every week until delivery, usually by ultrasound. Every 4-minute period of the cardiotocogram was scored and then the mean score was calculated for every test. The mean score for all the tests was 6,9 with a standard deviation of 1,8. In 1 patient a basal bradycardia was responsible for the low score. At the end of the pregnancy, the fetal heart rate in this patient fluctuated between 90 and 110/min. A heart rate above 180/min was seen on three occasions in 3 different patients. Tests before or after these episodes of tachycardia were all normal. Severe variable decelerations and non-reactive heart rate pattern in 1 patient were responsible for the lowest score seen in this study. This patient developed severe variable decelerations during labour; at caesarean section, the umbilical cord was tightly around the neck twice. The difference between the lowest and highest 4-minute scores was called the fluctuation of the score. Between 28 and 36 weeks the mean fluctuation of the score varied between 0,6 and 1,2. After 36 weeks however, the mean fluctuation suddenly increased to 1,67 at 37 weeks and to 1,9 at 38 weeks. After 38 weeks the score fluctuation gradually declined again. The mean score was not influenced by the duration of pregnancy.

Adolescent↗
PubMed1984

[The effect of maternal exercise on the fetal heart rate].

The effect of maternal exercise (the two-step test of Master) on the fetus was studied in 28 pregnant women. These subjects consisted of 5 cardiac cases, 5 cases with IUGR, 5 cases with preeclampsia and 13 normal pregnant women. Overt deceleration of the FHR was found after exercise only in 3 cardiac cases whose FHR tracings had been normal before. Slight changes such as a small rise or a small fall in FHR after exercise were seen in 4 of 7 cases who had shown decelerations in FHR before, and in a normal case. Fetal tachycardia appeared in 2 normal cases immediately before exercise; in one case the FHR tracing appeared not to be influenced by exercise; in the other case it rested at the normal baseline level after exercise. In most cases the amplitude of baseline variability remained unchanged or decreased after exercise. The severity of deceleration before exercise did not correlate well with the results of the exercise test. The exercise test did not reveal any new patients who might have placental insufficiency, suggesting that this procedure may not be warranted for evaluating a patient with placental insufficiency. Fetal response to exercise, however, may disclose a maternal hemodynamic problem. The exercise test with FHR monitoring should be recommended to a patient with heart disease.

Adolescent↗
PubMed1983

Cardiac orienting and vowel discrimination in newborns: crucial stimulus parameters.

To delineate the acoustic parameters crucial for eliciting a cardiac deceleratory response in newborns, 2 experiments investigated stimulus dimensions implicated as important by previous research. In experiment 1, the temporal pattern and spectral complexity of moderately intense auditory stimuli influenced the cardiac responses of 24 alert newborns. Temporal pattern determined response direction: pulsed stimuli elicited cardiac deceleration, whereas continuous stimuli elicited acceleration. Stimulus complexity influenced response magnitude: the most complex stimulus, a synthetically produced vowel, produced both the largest deceleration for pulsed stimuli and the largest acceleration for continuous ones. Experiment 2 (N = 16) extended the temporal pattern effect to other vowel stimuli in a no-delay discrimination paradigm. These findings indicate that the cardiac deceleratory response to auditory stimuli is a predictable component of the newborn infant's behavior. Furthermore, they suggest that stimulus parameters that influence cardiac deceleration may also play a critical role in stimulus discrimination.

Attention↗