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PubMed1986

The significance of antepartum variable decelerations.

A total of 4886 nonstress tests were reviewed to establish the relationship between antepartum variable decelerations and perinatal outcome. The association between various fetal heart rate components and variable decelerations was also studied. The incidence of variable decelerations, defined as three or more decelerations greater than or equal to 15 bpm lasting at least 15 seconds in a 20-minute period, was 1.3%. The results suggest that in the presence of variable decelerations: there is a higher incidence of fetal distress in labor, low Apgar scores, neonatal intensive care unit admissions, and nuchal cord involvement; the presence of accelerations and normal variability is associated with good neonatal outcome, whereas their absence is associated with adverse outcome; the presence of accelerations or good variability is not independently correlated with neonatal outcome.

Apgar Score↗
PubMed1996

Amniotic fluid index predicts the relief of variable decelerations after amnioinfusion bolus.

OBJECTIVE: Our purpose was to determine whether intrapartum amniotic fluid index before amnioinfusion can be used to predict response to therapeutic amnioinfusion. STUDY DESIGN: Intrapartum patients (n = 85) with repetitive variable decelerations in fetal heart rate that necessitated amnioinfusion (10 ml/min for 60 minutes) underwent determination of amniotic fluid index before and after bolus amnioinfusion. The fetal heart tracing was scored (scorer blinded to amniotic fluid index values) for number and characteristics of variable decelerations before and 1 hour after initiation of amnioinfusion. The amnioinfusion was considered successful if it resulted in a decrease of > or = 50% in total number of variable decelerations or a decrease of > or = 50% in the rate of atypical or severe variable decelerations after administration of the bolus. Spontaneous vaginal births before completion of administration of the bolus (n = 18) were excluded from analysis. The probability of success of amnioinfusion in relation to amniotic fluid index was analyzed with the chi(2) test for progressive sequence. RESULTS: The mean amniotic fluid index before amnioinfusion was 6.2 +/- 3.3 cm. An amniotic fluid index of < or = 5 cm was present in 40% of patients (27/67), and an amniotic fluid index of < or = 8 cm was present in 72% of patients (48/67). The probability of success of amnioinfusion decreased with increasing amniotic fluid index before amnioinfusion (76% [16/21] when initial amniotic fluid index was 0 to 4 cm, 63% [17/27] when initial amniotic fluid index was 4 to 8 cm, 44% [7/16] when initial amniotic fluid index was 8 to 12 cm, and 33% [1/3] when initial amniotic fluid index was > 12 cm, p = 0.03). The incidence of nuchal cords or true umbilical cord knots increased in relation to amniotic fluid index before amnioinfusion. CONCLUSIONS: Amniotic fluid index before amnioinfusion can be used to predict the success of amnioinfusion for relief of variable decelerations in fetal heart rate. Failure of amnioinfusion at a high amniotic fluid index before amnioinfusion may be explained by the increased prevalence of nuchal cords or true knots in the umbilical cord.

Adult↗
PubMed1997

Doppler blood flow velocity waveforms of the umbilical artery during variable decelerations in labor.

OBJECTIVE: To investigate the changes in resistance indices of blood flow velocity waveforms of the umbilical artery (UmA-RIs) during variable decelerations (VDs) vs. early decelerations (EDs). METHODS: UmA-RIs were measured before and during uterine contractions in 30 cases with VDs, nine cases with EDs and 20 cases without decelerations. In 12 out of 30 cases with VDs, UmA-RI was determined at the following five stages of a VD; before the deceleration, downward, bottom, upward and resumption stages. RESULTS: UmA-RIs during VDs were significantly higher compared with those at preceding periods. UmA-RIs at downward and bottom stages of VDs were significantly higher than those at the upward stage, although no differences in heart rate were found between downward and upward stages. UmA-RIs during EDs or uterine contractions without decelerations did not differ from those preceding them. CONCLUSION: UmA-RIs increased during VDs, particularly at downward and bottom stages during which the cord seemed to be actually compressed.

Blood Flow Velocity↗
PubMed2003

Failure of the biceps superior labral complex: a cadaveric biomechanical investigation comparing the late cocking and early deceleration positions of throwing.

PURPOSE: The goal of the study was to determine which position of the throwing motion, late-cocking or early deceleration, was more likely to produce lesions of the biceps superior labral complex. TYPE OF STUDY: Cadaveric biomechanical model. METHODS: Ten paired cadaver shoulders were prepared and mounted on a custom testing apparatus in 60 degrees glenohumeral abduction with the humerus in the plane of the scapula. All specimens were loaded with 100 cycles of subfailure external rotation torque (7.9 N-m) with 22 N applied to the rotator cuff tendons and long head of the biceps tendon. One of each pair of specimens was randomly tested in a late cocking position for throwing (>125 degrees external rotation, 60 degrees glenohumeral abduction, in the plane of the scapula). The other was tested in a position of early deceleration (80 degrees external rotation, 60 degrees glenohumeral abduction, 16 degrees horizontal adduction). The biceps was loaded to failure with the shoulder fixed in these positions. The specimens were then examined by 2 experienced shoulder surgeons, blinded to the test protocol, to assess for the presence of a type II SLAP lesion. RESULTS: Failure of the biceps superior labral complex occurred at the superior glenoid in 9 of 10 specimens in the late cocking position and in 2 of 10 specimens in the early deceleration position (P =.055). Five specimens developed type II SLAP lesions, with more in the late cocking position (4 of 10) than in the early deceleration position (1 of 10; P =.12). Load to failure was significantly less for the late cocking position (289 +/- 39 N) than for the early deceleration position (346 +/- 40 N; P =.004). CONCLUSIONS: These results suggest that the late cocking position may contribute to biceps-superolabral complex injuries in the thrower's shoulder.

Adult↗
PubMed1991

Reflection as a cause of mid-systolic deceleration of pulmonary flow wave in dogs with acute pulmonary hypertension: comparison of pulmonary artery constriction with pulmonary embolisation.

STUDY OBJECTIVE: The aim was to examine whether mid-systolic deceleration of the pulmonary flow wave occurred in acute pulmonary hypertension due to pulmonary artery constriction and pulmonary embolisation, and if so whether it was related to reflection. DESIGN: Various degrees of pulmonary hypertension were induced by both pulmonary artery constriction and pulmonary embolisation in dogs. During control periods and during pulmonary artery constriction and pulmonary embolisation, pulmonary flow and pulmonary artery pressure were recorded, and the forward and backward (reflected) flow waves were separated from the measured pulmonary flow wave by the method of Westerhof et al. MATERIALS: 20 adult mongrel dogs were used and 10 dogs qualified for analysis. The other 10 dogs, which died before both interventions were completed, were excluded. MEASUREMENTS AND MAIN RESULTS: During pulmonary artery constriction, a distinct mid-systolic deceleration of the pulmonary flow wave was observed in five of the 10 dogs, while during pulmonary embolisation, no mid-systolic deceleration was found in these five dogs. The distinct deceleration of the pulmonary flow wave was related to a steep fall and early negative peak in the backward flow wave. CONCLUSION: Mid-systolic deceleration of pulmonary flow wave is likely to be related to reflection.

Acute Disease↗
PubMed1977

Nonspecific decelerations in fetal heart rate during high-risk pregnancy.

Solitary nonspecific decelerations in fetal heart rate occurring in three patients during antepartum cardiotocography are described. The decelerations were nonspecific in that they were neither variable nor late nor associated with maternal hypotension. All occurred in pregnancies complicated by hypertension and placental insufficiency. In the three patients described, the fetus lived for at least three days after the first nonspecific deceleration was observed. Although solitary nonspecific decelerations may indicate may indicate danger to the fetus from placental insufficiency, these decelerations should not be considered as an indication for immediate delivery.

Adult↗
PubMed2006

Stark deceleration and trapping of OH radicals.

The motion of polar molecules can be controlled by time-varying inhomogeneous electric fields. In a Stark decelerator, this is exploited to accelerate, transport, or decelerate a fraction of a molecular beam. When combined with a trap, the decelerator provides a means to store the molecules for times up to seconds. Here, we review our efforts to produce cold molecules via this technique. In particular, we present a new generation Stark decelerator and electrostatic trap that selects a significant part of a molecular beam pulse that can be loaded into the trap. Deceleration and trapping experiments using a beam of OH radicals are discussed.

Journal Article↗
PubMed1999

Myocardial perfusion and angiographic findings in patients with paradoxical sinus deceleration during dobutamine technetium-99m sestamibi-gated SPECT imaging.

AIMS: Dobutamine-gated SPECT imaging allows simultaneous perfusion and function assessment and is an alternative stress method for evaluating coronary artery disease in patients unable to perform treadmill exercise. In some patients, a paradoxical decrease in heart rate has been observed during high dose dobutamine infusion. The purpose of this study was to describe the paradoxical decrease in heart rate observed during dobutamine perfusion scintigraphy and determine its relation to inducible ischemia and angiographic coronary artery disease. METHODS AND RESULTS: We studied 52 patients who underwent dobutamine-gated (99m)Tc sestamibi SPECT imaging and coronary angiography within 30 days. Paradoxical deceleration was defined as a decrease in heart rate >/=5 beats/min lasting at least 3 min during dobutamine infusion. Perfusion was graded on a five-point scale (0 = normal; 4 = absent uptake) and wall motion on a four-point scale (0 = akinesia/dyskinesia; 3 = normal) using the 20-segment model. Significant coronary artery disease was defined as >/=50% narrowing of lumen diameter of a major epicardial artery. Paradoxical deceleration occurred in 10 patients (19%, 95% CI 8-30%). A decrease in systolic blood pressure [8 patients (80%), 95% CI 56-92%] with angina [5 patients (50%), 95% CI 23-71%] often accompanied the decrease in heart rate. All 10 patients with sinus deceleration had an inferior wall perfusion defect and 8 of them had a corresponding wall motion abnormality on gated images. Significant coronary artery disease was present in all 10 patients with sinus deceleration, with an increased incidence of right coronary artery stenosis (p = 0.007). CONCLUSIONS: Paradoxical deceleration observed during dobutamine perfusion scintigraphy is associated with inducible ischemia and angiographic coronary artery disease and the underlying mechanism for this phenomenon may be the activation of the Bezold-Jarisch reflex.

Aged↗
PubMed2005

Erythromycin antagonizes the deceleration of gastric emptying by glucagon-like peptide 1 and unmasks its insulinotropic effect in healthy subjects.

Glucagon-like peptide 1 (GLP-1) has been proposed to act as an incretin hormone due to its ability to enhance glucose-stimulated insulin secretion. Because GLP-1 also decelerates gastric emptying, it physiologically reduces rather than augments postprandial insulin secretory responses. Therefore, we aimed to antagonize the deceleration of gastric emptying by GLP-1 to study its effects on insulin secretion after a meal. Nine healthy male volunteers (age 25 +/- 4 years, BMI 25.0 +/- 4.9 kg/m2) were studied with an infusion of GLP-1 (0.8 pmol.kg(-1).min(-1) from -30 to 240 min) or placebo. On separate occasions, the prokinetic drugs metoclopramide (10 mg), domperidone (10 mg), cisapride (10 mg, all at -30 min per oral), or erythromycin (200 mg intravenously from -30 to -15 min) were administered in addition to GLP-1. A liquid test meal (50 g sucrose and 8% mixed amino acids in 400 ml) was administered at 0 min. Capillary and venous blood samples were drawn for the determination of glucose (glucose oxidase), insulin, C-peptide, GLP-1, glucagon, gastric inhibitory polypeptide (GIP), and pancreatic polypeptide (specific immunoassays). Gastric emptying was assessed by the phenol red dilution technique. Statistical analyses were performed using repeated-measures ANOVA and Duncan's post hoc test. GLP-1 significantly decelerated the velocity of gastric emptying (P < 0.001). This was completely counterbalanced by erythromycin, whereas the other prokinetic drugs used had no effect. Postprandial glucose concentrations were lowered by GLP-1 (P < 0.001 vs. placebo), but this effect was partially reversed by erythromycin (P < 0.05). Insulin secretory responses to the meal were lower during GLP-1 administration (P < 0.05 vs. placebo). However, when erythromycin was added to GLP-1, insulin concentrations were similar to those in placebo experiments. The suppression of meal-related increments in glucagon secretion by GLP-1 was reversed by erythromycin (P < 0.001). The time course of GIP secretion was delayed during GLP-1 administration (P < 0.05), but when erythromycin was added, the pattern was similar to placebo experiments. GLP-1 administration led to a reduction in pancreatic polypeptide plasma concentrations (P < 0.05). In contrast, pancreatic polypeptide levels were markedly increased by erythromycin (P < 0.001). Intravenous erythromycin counteracts the deceleration of gastric emptying caused by GLP-1, probably by interacting with the parasympathetic nervous system (pancreatic polypeptide responses). Despite augmented rises in insulin secretion, the glucose-lowering effect of GLP-1 is markedly reduced when the deceleration of gastric emptying is antagonized, illustrating the importance of this facet of the multiple antidiabetic actions of GLP-1.

Adult↗
PubMed1999

Prognostic value of Doppler-derived mitral deceleration time in postinfarction patients with left ventricular ejection fractions of 35% or more.

Short Doppler-derived mitral deceleration time of early filling has been proved to be an independent predictor of poor prognosis in patients with left ventricular dysfunction. However, the prognostic value of Doppler-derived mitral deceleration time in postinfarction patients without overt left ventricular dysfunction is poorly understood. A total of 27 survivors of acute myocardial infarction with left ventricular ejection fractions of 35% or more, as determined by radionuclide ventriculography, were prospectively studied. Doppler study was performed 5 to 7 days after the index infarction. The patients were divided into two groups. Group A included 10 patients whose mitral deceleration time was 125 msec or less and group B consisted of 17 patients whose mitral deceleration time was 125 msec or more. The two groups were similar in terms of age and gender distribution and there were no statistically significant differences in coronary risk factors, peak creatine kinase concentration, location of infarction, Killip classification, thrombolytic therapy, left ventricular ejection fraction, or medications. After a mean follow-up period of 30 months, the rate of congestive heart failure (New York Heart Association, NYHA, class II or above) was significantly higher in group A (5/10) than in group B (1/17) (p < 0.01). These results suggest that a short mitral deceleration time could be a useful early predictor of the potential development of future congestive heart failure in postinfarction patients with left ventricular ejection fractions of 35% or more.

Blood Flow Velocity↗
PubMed1982

[Studies on the safe limit of variable decelerations during labor].

Ninety neonates who presented variable decelerations during labor were divided into two groups, according to the one-minute Apgar scores of greater than or equal to 8 and 7 less than or equal to. Only neonates of singleton pregnancies and cephalic presentations of 34 weeks gestation or more were included in the study. Several parameters of this fetal heart rate (FHR) pattern and the presence or absence of meconium staining were compared. Followings were found to be statistically significant. 1) The duration of the variable deceleration (less than 2 hours). 2) The FHR deceleration/uterine contraction ratio (less than 80%). 3) The absence of meconium staining. An effort was made to establish safe limits of variable decelerations. These are shown in parentheses. Based on both these data and findings of others, a multifactorial scoring system named a variable deceleration score was proposed for the proper management of this FHR pattern. Five variables were selected for the system. These were: The duration of variable decelerations, the FHR deceleration/uterine contraction ratio, the duration and amplitude of dips, and the presence or absence of meconium staining. The system scores from 0 to 2 for each of five factors, and was designed to be able to predict depressed neonates with the numerical increase of the score.

Female↗
PubMed1980

Fetal blood and tissue pH with variable deceleration patterns.

Continuous tissue pH, scalp blood pH, and umbilical artery pH were studied in 89 patients with variable decelerations and 5 control patients in labor. The characteristics of the variable decelerations were analyzed. The deceleration pattern was classified as variable without late component (V), variable with late onset (VLO), or variable with late recovery (VLR). The patterns with a late component showed a greater incidence of falling pH during the decelerations. The VLR pattern was very likely to show a tendency to fetal acidosis and a high incidence of low Apgar scores. Variable decelerations without a late component were found to be innocuous. The VLO was an intermediate pattern, often progressing to the potentially more hazardous pattern of VLR.

Apgar Score↗
PubMed1981

Fetal heart rate decelerations during a nonstress test.

In a review of 2000 nonstress tests (NSTs) on 972 pregnant women at high risk at the authors' institution, 94 exhibited fetal heart rate (FHR) decelerations in response to fetal activity in 110 (46.6%) of the 236 NSTs. The NST results were interpreted as either reactive (178) or nonreactive (58). Of those cases with an FHR deceleration pattern, an abnormal cord position was observed in 55.3% (X2 = 68; P less than .001). Of the 74 patients who went into labor, 59.5% demonstrated variable FHR decelerations. Moreover, 8.5% required cesarean section for fetal distress. Of greater importance, 3 intrauterine fetal deaths occurred that appeared to be related to the abnormal cord position. FHR decelerations may occur during reactive as well as nonreactive NSTs. When FHR decelerations are present, they may signify some form of abnormal cord position and require further evaluation by ultrasonography and a contraction stress test.

Adult↗
PubMed1998

Deceleration in the age pattern of mortality at older ages.

The rate of mortality increase with age tends to slow down at very old ages. One explanation proposed for this deceleration is the selective survival of healthier individuals to older ages. Data on mortality in Sweden and Japan are generally compatible with three predictions of this hypothesis: (1) decelerations for most major causes of death; (2) decelerations starting at younger ages for more "selective" causes; and (3) a shift of the deceleration to older ages with declining levels of mortality. A parametric model employed to illustrate the third prediction relies on the distinction between senescent and background mortality. This dichotomy, though simplistic, helps to explain the observed timing of the deceleration.

Age Distribution↗
PubMed1982

Voluntary heart rate deceleration: a critical evaluation.

This experiment was designed as a test of the view that the human heart rate (HR) deceleration response can be brought under voluntary control, when some form of exteroceptive feedback is available. Sixteen female volunteers were randomly assigned to two groups. The first group received instructions to decrease their HR plus a continuous negative (failure) binary feedback, while the second group received only the instructions. Each subject was given four sessions of HR deceleration training. Two identical tests were presented, one before and the other after the series of training sessions. These tests were divided into two parts. In the first part, subjects attempted to decrease their HR while undergoing an ischemic arm pain stress. In the second part, subjects performed a 40-trial HR discrimination task. The results indicate that all subjects decrease HR during both rest and voluntary control periods within each training session, but there are no significant group differences, no improvement in HR deceleration control over the four training sessions, and no difference in performance between rest and voluntary control periods. Similarly HR, blood pressure (BP), and the HR x BP product levels during the ischemic stress condition and the HR discrimination performance do not show group differences. It is suggested that the HR deceleration response may not meet the criteria generally applied to the definition of a voluntary response.

Adolescent↗
PubMed1982

Mechanisms of late decelerations of the fetal heart rate during hypoxia.

Transient maternal aortic occlusion decreases uterine blood flow and results in the delayed deceleration of the fetal heart rate. The response to this maneuver was examined in the hypoxic fetus. Pregnant ewes and their fetuses at 0.8 gestation were catheterized for chronic study. A blood flow transducer was placed around the common umbilical artery, and a Fogarty balloon-tipped catheter was placed in the maternal abdominal aorta distal to the renal arteries. The ewes were made hypoxic by breathing a hypoxic gas mixture through a mask placed over their faces. Transient maternal aortic occlusion resulted in a delayed and transient deceleration of the fetal heart rate in hypoxic fetuses, associated with a significant decrease in mean arterial pressure and umbilical blood flow. Infusion of atropine into the fetus before maternal aortic occlusion modified but did not abolish the fetal heart rate response. The deceleration was associated with the significant decrease in the "double-product" index of myocardial oxygen consumption. The conclusion is that late decelerations result from two mechanisms: chemoreceptor vagal reflex mechanisms and hypoxic myocardial depression.

Animals↗
PubMed1986

Variable decelerations during nonstress tests are not a sign of fetal compromise.

An examination of 908 fetal heart rate tests of 418 consecutive patients revealed brief variable decelerations in more than 50.7% of the patients. Although an association existed with nuchal cord location found at delivery, no association existed between these variable decelerations and fetal heart rate decelerations during labor, low Apgar scores at birth, or birth weight. We find no evidence to suggest that these brief variable decelerations are a sign of fetal compromise or an indication for obstetric intervention.

Apgar Score↗
PubMed1990

Effect of uterine contractility and maternal hypotension on prolonged decelerations after bupivacaine epidural anesthesia.

Patients with prolonged decelerations after bupivacaine epidural anesthesia were matched with control patients. It was found that there were no differences in the decrease in mean arterial blood pressure after epidural anesthesia between those with prolonged decelerations (5 +/- 9 mm Hg) and those without (5 +/- 9 mm Hg). Uterine hypertonus was suggested as a cause in the prolonged deceleration group as a result of a higher rate of subjective impressions of uterine hypertonus (82% vs 11%) and more frequent use of terbutaline (30% vs 0%) after epidural anesthesia. With patients with internal uterine pressure monitors used as their own controls, it was also found that basal uterine tone was higher during periods when the deceleration occurred (26 +/- 9 mm Hg) than when it did not (13 +/- 4 mm Hg), and in comparison to windows before epidural anesthesia (12 +/- 5 mm Hg).

Adult↗