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PubMed1997

Evaluation of interobserver agreement of cardiotocograms.

OBJECTIVE: To evaluate interobserver agreement in visual analysis of each cardiotocographic event. METHODS: Three experts independently divided 16 antepartum and 17 intrapartum cardiotocograms into baseline segments, accelerations and decelerations, according to the FIGO guidelines. Baseline segments were further classified as having normal, reduced or increased variability and decelerations as early, late and variable. Uterine activity was divided into tonus and contractions. Agreement was assessed by the proportions of agreement (pa) with 95% confidence intervals. RESULTS: Reproducibility in assessment of baseline segments with normal variability, accelerations and uterine activity was acceptable (pa = 0.56-0.71) whereas that of other segments was not (pa = 0.14-0.45). CONCLUSIONS: Analysis of most cardiotocographic events is poorly reproducible, even when experts use the FIGO guidelines. This may be explained by some still ambiguous guidelines, by eyeball limitations in evaluation of subtle events, and by the incapacity of busy clinicians to assess complex and multiple cardiotocographic events in a systematic and disciplined fashion.

Cardiotocography↗
PubMed2000

Intrapartum fetal distress and magnesium sulfate.

OBJECTIVE: Intrapartum fetal distress is an obstetric emergency traditionally managed by immediate delivery by either the vaginal route or cesarean section. However, there is usually time to attempt intrauterine resuscitation. The purpose of this study was to report the utilization of magnesium sulfate for intrauterine resuscitation. METHOD: Twenty-one fetuses received magnesium sulfate 4-g intravenous bolus in mothers awaiting cesarean section for fetal distress in the labor room of the Complejo Hospitalario Metropolitano de la Caja de Seguro Social de Panamá, from March through August 1997. Fetal distress in labor was defined as the presence of repetitive late decelerations, persistent loss of baseline variability, severe variable decelerations, or bradycardia. RESULTS: Twenty-one fetuses received magnesium sulfate 4-g intravenous bolus in mothers awaiting cesarean section for fetal distress. Uterine activity ceased in seven patients, diminished in 13 patients and did not change in one. In all cases, but one, there was recovery of the FHR within 4 min; furthermore there was rose reactive of FHR in nine patients. The 1-min Apgar scores were 7 or above in 18 cases and the 5-min Apgar scores were 7 or above in 20 patients. CONCLUSIONS: In summary, magnesium sulfate may be useful in the management of acute intrapartum fetal distress when there is evidence of increased uterine activity.

Anti-Arrhythmia Agents↗
PubMed1999

Dynamics of the long jump.

A mechanical model is proposed which quantitatively describes the dynamics of the centre of gravity (c.g.) during the take-off phase of the long jump. The model entails a minimal but necessary number of components: a linear leg spring with the ability of lengthening to describe the active peak of the force time curve and a distal mass coupled with nonlinear visco-elastic elements to describe the passive peak. The influence of the positions and velocities of the supported body and the jumper's leg as well as of systemic parameters such as leg stiffness and mass distribution on the jumping distance were investigated. Techniques for optimum operation are identified: (1) There is a minimum stiffness for optimum performance. Further increase of the stiffness does not lead to longer jumps. (2) For any given stiffness there is always an optimum angle of attack. (3) The same distance can be achieved by different techniques. (4) The losses due to deceleration of the supporting leg do not result in reduced jumping distance as this deceleration results in a higher vertical momentum. (5) Thus, increasing the touch-down velocity of the jumper's supporting leg increases jumping distance.

Biomechanical Phenomena↗
PubMed2000

Strain relief from the cerebral ventricles during head impact: experimental studies on natural protection of the brain.

Physical models of the parasagittal human skull/brain have been tested to investigate whether the cerebral ventricles provide natural protection of the brain by relieving strain during head rotation. A sophisticated model included anatomical structures, and a semicircular model consisted of a cylinder divided into two semicircles. Silicone gel simulated the brain and was detached from the vessel by a layer of liquid paraffin simulating the cerebrospinal fluid. Both models were run with and without an elliptical inclusion filled with liquid paraffin simulating a cerebral ventricle. The 2D models were exposed to angular acceleration by a pendulum impact causing 7600 rad/s2 peak rotational acceleration with 6 ms pulse duration. After rotating 100 degrees, the models were decelerated during 30 ms. The trajectory of grid markers was analyzed from high-speed video (1000 frames/s). Rigid-body displacement, shear strain and principal strain were determined from the displacement of three-point sets inferior and superior to the ventricle. For the subventricular (inferior) region in the sophisticated model, approximately 40% lower peak strain values were obtained in the model with ventricle than in the one without. Subcortical displacement was reduced by 12%. Corresponding strain reduction in the subcortical (superior) region was approximately 40% following the acceleration and 25% following the deceleration. Similar but less pronounced effects were found for the semicircular model. The lateral ventricles play an important role as strain relievers and provide natural protection against brain injury.

Brain↗
PubMed1994

Effects of activation sequence on the spatial distribution of repolarization properties.

The electrotonic effects of activation spread on the spatial distribution of repolarization properties were studied in animal experiments and with computer simulations. Refractory periods (RPs) were measured at 36 sites within a 1.0 cm2 region of the epicardial surface of the canine pulmonary conus during 37 drives in 11 experiments. In each experiment three or four sites along the perimeter of the region bounding the RP test sites were driven. Activation propagated uniformly during some and nonuniformly during other drives in the same animals. In general, RPs were distributed uniformly when activation spread uniformly and nonuniformly when activation spread nonuniformly. The authors observed RP differences as large as 16 ms between sites with 2 mm separation during drive from some epicardial sites in these normal canine hearts. Indices of nonuniformity of activation and of relative RP values were used to quantify the relation between nonuniformity of activation spread and the spatial distribution of the RP. There was a significant negative correlation between nonuniformity of activation and RP indices during the 19 drives in which activation spread nonuniformly. This indicated that RPs were relatively long at sites where activation spread decelerated and relatively short at sites where activation spread accelerated. When nonuniform activation spread was simulated by introducing high-resistance barriers in a model with fixed anisotropic conductivities, there were marked spatial variations in action potential duration. The spatial variations in action potential duration were negatively correlated to acceleration and deceleration of activation spread. The major new finding of this study is that the spatial distributions of RPs are markedly affected by activation spread. Since both characteristics of activation sequence and nonuniformity of RP distributions have roles in reentrant arrhythmias, the findings suggest that some sites of origin of premature activity may be more arrhythmogenic than others. The findings may also explain why ventricular tachycardia can sometimes be initiated from one but not from other sites in patients undergoing electrophysiologic testing.

Action Potentials↗
PubMed1995

Troponin C-mediated calcium sensitization by levosimendan accelerates the proportional development of isometric tension.

The effects of various calcium sensitizers on myosin-actin crossbridge kinetics were evaluated in intact, paced guinea-pig papillary muscle by analysing the velocity of the development of isometric tension (dT/dt) in detail. The effect on association (the whole sequence of events from troponin onward) and dissociation rates of crossbridges was estimated from the rising phase and from the early decay phase of the normalized dT/dt curve. Levosimendan, a calcium sensitizer acting through troponin C, accelerated the proportional association rate and decelerated the dissociation rate of crossbridges. The effect of levosimendan on crossbridge kinetics occurred before the peak twitch tension was achieved. Thus, the compound did not change the actual relaxation phase of twitch tension. Since the effect on the association was more pronounced than on the dissociation of crossbridges, levosimendan shifted the entire twitch tension curve to the left. Based on the dissociation rate analysis levosimendan seems to act preferentially as a calcium sensitizer at low concentrations. At high concentrations the phosphodiesterase III (PDE III) inhibitory properties of levosimendan modulated its effect on the early relaxation processes. In contrast, PDE III inhibition is probably the primary mechanism of action for MCI-154. Pimobendan, and EMD 53998 at low concentrations, whereas their direct effects on crossbridge kinetics contributed to the positive inotropic action at high concentrations. The calcium sensitizing mechanisms of these compounds seemed to be based almost exclusively on the decelerating effect on dissociation of crossbridges.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1998

Age-dependent telomere shortening is slowed down by enrichment of intracellular vitamin C via suppression of oxidative stress.

Telomeres in eukaryotic somatic cells are destined to the age-dependent shortening, which has not been demonstrated to correlate to direct lesion of telomeric DNA by reactive oxygen intermediates (ROI); still less explicable is the inhibitory effect of ROI-scavenging on telomere shortening. Here, we succeeded in artificial slowdown of age-dependent telomere shortening to 52-62% of the untreated control, in human vascular endothelial cells, by addition of the oxidation-resistant type of ascorbic acid (Asc), Asc-2-O-phosphate (Asc2P), which concurrently achieved both extension of cellular life-span and prevention of cell size enlargement indicative of cellular senescence. The results are attributable to a 3.9-fold more marked enrichment of intracellular Asc (Asc(in)) by addition of Asc2P, subsequently dephosphorylated before or during transmembrane influx, than by addition of Asc itself, and also attributed to diminution of intracellular ROI to 53% of the control level by Asc2P; telomerase activity was at a trace level and underwent an age-dependent decline, which was significantly decelerated by Asc2P. Thus, age-dependent telomere-shortening can be decelerated by suppression of intracellular oxidative stress and/or by telomerase retention, both of which are achieved by enriched Asc(in) but not by extracellular Asc overwhelmingly more abundant than Asc(in).

Ascorbic Acid↗
PubMed2001

Visual illusions and the control of children arm movements.

The aim of the present study was to determine whether children like adults (Gentilucci M, Chieffi S, Daprati E, Saetti MC, Toni I. Visual illusion and action. Neuropsychologia 1996;34:369-76; Gentilucci M, Daprati E, Gangitano M, Toni I. Eye position tunes the contribution of allocentric and egocentric information to target localisation in human goal directed arm movements. Neurosci Lett 1997;222:123-6) are influenced by visual illusions when they transform visual information in motor command. Children and adults pointed to a shaft extremity of the Müller-Lyer configurations, as well as to an extremity of a control configuration. Movements were executed in two experimental conditions. In the vision condition subjects saw both the stimulus and their hand before and during movement. In the no vision (memory) condition subjects saw the stimulus and their hand before, but not during movement. Movement started 5 s after vision was precluded. The Müller-Lyer illusion affected pointing kinematics of both children and adults. As found previously (Gentilucci M, Chieffi S, Daprati E, Saetti MC, Toni I. Visual illusion and action. Neuropsychologia 1996;34:369-76; Gentilucci M, Daprati E, Gangitano M, Toni I. Eye position tunes the contribution of allocentric and egocentric information to target localisation in human goal directed arm movements. Neurosci Lett 1997;222:123-6), subjects undershot and overshot the shaft extremity of the closed and of the open configuration, respectively. The illusion effect was greater in the no vision than in the vision condition. These results show that in children like in adults the system underlying visual perception in an object-centered frame of reference and that involved in motor control functionally interact with each other. Although the processes of target localisation were the same, the transformation of target position information in a sequence of motor patterns was different in children from that in adults. Even if both children and adults lengthened duration of the deceleration phase in the vision condition, only adults shortened duration of the acceleration phase in order to maintain constant movement time (Viviani P, Schneider R. A developmental study of the relationship between geometry and kinematics in drawing movements. J Exp Psychol 1991;17:198-218). This result suggests that children are yet unable to co-ordinate temporally acceleration with deceleration phase.

Acceleration↗
PubMed2000

The reach-to-grasp movement in Parkinson's disease before and after dopaminergic medication.

The aim of the present study was to assess the effects of dopaminergic medication on the organisation of the reach-to-grasp movement in Parkinson's disease. A three-dimensional kinematic system (ELITE, B/T/S Italy) was used to record reach-to-grasp movements to objects of either small (0.7 cm) or large (8 cm) diameter placed at a reaching distance of either 20 or 30 cm. Vision of the reaching limb and target was also manipulated. Parkinson's disease participants (N = 14) were assessed in 'OFF' (12 h without medication) and 'ON' (1-2 h post-administration of medication) states. In the 'ON' state, movement duration and the time spent in arm deceleration were significantly less than in the 'OFF' state. The amplitudes of peak reaching velocity, acceleration and deceleration were all higher in the 'ON' than in the 'OFF' state. Further, in the 'ON' state, the acceleration profile no longer exhibited small irregular adjustments, the number of significant correlations between parameters measured from the transport and manipulation components was greater, and the movement was more direct in both the mediolateral horizontal and vertical planes. These results indicate that dopaminergic medication is of benefit in reducing bradykinesia and in fine-tuning kinematic parameterisation of a selected reach-to-grasp action.

Adult↗
PubMed2000

Movement accuracy constraints in Parkinson's disease patients.

This study examined the hypothesis that the kinematics of movements performed by PD (Parkinson's disease) patients are differentially affected depending on whether or not the aiming movement has an accuracy constraint. The aiming movements required elbow extension in the horizontal plane on a digitizer. There were two movement conditions: (1) one having a spatial accuracy requirement in which the subjects moved to the defined target and stopped on it; and (2) one requiring the subjects to move toward the defined target without stopping precisely on it. Subjects were instructed to make their movements as fast and as accurate as possible in response to the auditory imperative signal. PD patients modified the movement speed and kinematics depending on the two accuracy conditions. However, when the accuracy constraint was imposed, movement slowness observed in the patients was much more pronounced. The most revealing result was localized to the deceleration phase, particularly as the target was approached. The patients also were found to make a higher number of acceleration zero crossings from negative to positive to reach the target, indicating that the movements were more irregular. For the patients, the first acceleration zero crossing from negative to positive occurred much earlier in the movement than that for the controls. In addition, when movement accuracy was constrained, the number of zero crossings was accentuated. These data show that when PD patients make aiming movements to a target, their deceleration phase becomes longer and more variable.

Aged↗
PubMed2001

Clinical significance of fetal heart rate tracings during the second stage of labor.

OBJECTIVE: To examine the significance of abnormal fetal heart rate (FHR) patterns during the second stage of labor in terms of pregnancy outcome. METHODS: A prospective observational study comparing women who had abnormal FHR patterns during the second stage of labor with women who demonstrated normal FHR patterns. RESULTS: Abnormal second-stage FHR patterns were found in 420 tracings (75%), whereas 140 tracings (25%) were normal. In a multivariable analysis, nulliparity (odds ratio [OR] 2.5; 95% confidence interval [CI] 1.5, 4.2), cord problems (OR 1.8; 95% CI 1.03, 3.3), and male sex (OR 1.5; 95% CI 1.01, 2.2) were independent factors affecting the occurrence of abnormal second-stage FHR patterns. Patients with abnormal tracings had significantly higher rates of operative delivery compared with patients with normal tracings. The newborns from the case group had significantly higher percentages of Apgar scores lower than 7 at 1 minute, arterial pH lower than 7.2, and base deficit of 12 mmol/L or higher, and six were admitted to the intensive care unit (ICU). A multiple logistic regression model found second-stage late decelerations, bradycardia less than 70 beats per minute, and the presence of abnormal FHR patterns during the first stage of labor to be independently associated with fetal acidosis (determined by pH less than 7.2 and base deficit greater than 12 mmol/L). CONCLUSION: Late decelerations, bradycardia less than 70 beats per minute, and abnormal FHR patterns during the first stage of labor might jeopardize fetal well-being, and expedited delivery should be considered.

Adult↗
PubMed2002

Active pushing versus passive fetal descent in the second stage of labor: a randomized controlled trial.

OBJECTIVE: To compare perinatal outcomes among women with epidural anesthesia who were encouraged to push at complete dilatation with those who had a period of rest before pushing began. METHODS: After a power analysis to determine appropriate sample size (based upon an alpha error rate of.05% and 80% power), a prospective randomized trial of 252 women with epidural anesthesia was conducted. Patients were randomized to a rest period or immediate pushing at complete dilatation. Variables measured included rate of fetal descent, length of time of pushing, the number and type of fetal heart rate decelerations, Apgar scores, arterial cord pH values, perineal injuries, type of delivery, length of second stage, maternal fatigue, and endometritis. RESULTS: When a period of rest was used before pushing, we found a longer second stage, decreased pushing time, fewer decelerations, and, in primiparous women, less fatigue compared with control patients. Apgar scores, arterial cord pH values, rates of perineal injury, instrument delivery, and endometritis were similar in both groups. CONCLUSION: Delayed pushing was not associated with demonstrable adverse outcome, despite second-stage length of up to 4.9 hours. In select patients, such delay may be of benefit.

Adult↗
PubMed2002

Gestational cocaine exposure and intrauterine growth: maternal lifestyle study.

OBJECTIVE: To estimate the effects of cocaine exposure on intrauterine growth and to investigate at what point in gestation growth deviation would be manifested. METHODS: This is a secondary analysis of data from a multicenter project, the Maternal Lifestyle Study, designed to determine infant outcomes of in utero cocaine or opiates exposure. Four centers of the National Institute of Child Health and Human Development Neonatal Research Network enrolled 11,811 maternal-infant dyads. A total of 1072 infants were cocaine exposed, 7565 were cocaine negative by maternal history and meconium results, and 3174 were excluded from analysis because of unconfirmed negative exposure. Outcome measures included birth weight, length, and head circumference. RESULTS: Percentile estimates for birth weight, length, and head circumference revealed growth deceleration in cocaine-exposed infants evident after 32 weeks' gestation. There was significant interaction between cocaine and gestational age. After controlling for confounders, at 40 weeks' gestation, cocaine exposure was estimated to be associated with a decrease of 151 g, 0.71 cm, and 0.43 cm in birth weight, length, and head circumference, respectively. Smoking had a negative impact on all growth measurements, with some indication of a dose-effect relationship. Heavy alcohol use was associated with decrease in weight and length only. Opiates had significant effect only on birth weight. CONCLUSION: In utero cocaine exposure is associated with growth deceleration involving all measurements, becoming more pronounced with advancing gestation.

Adult↗
PubMed2002

The effect of a nitric oxide donor on fetal heart rate patterns in patients with hypertension.

OBJECTIVE: To estimate whether nitric oxide donors can be administered safely to patients with pregnancy-associated hypertension based on computer analysis of antepartum fetal heart rate (FHR) tracings. METHODS: Thirty-minute recordings of FHR and fetal movements, before (stage I) and after (stage II) sublingual administration of 5 mg of isosorbide dinitrate, a nitric oxide donor, were obtained in 20 women with pregnancy-associated hypertension. RESULTS: Baseline FHR in stage I did not differ significantly from that in stage II (140.9 +/- 2.0 beats per minute and 137.5 +/- 2.1 beats per minute, respectively). There were no significant differences between stage I and II in the number (9.67 +/- 1.14 versus 9.56 +/- 1.07), amplitude (26.14 +/- 1.03 versus 24.5 +/- 0.85 beats per minute), and duration (36.03 +/- 1.46 versus 34.04 +/- 1.57 seconds) of heart rate accelerations. During stage II, the number (1.39 +/- 0.43) and duration (26.9 +/- 1.38 seconds) of heart rate decelerations did not change significantly as compared with stage I (1.67 +/- 0.33 and 26.23 +/- 1.13 seconds, respectively). However, the amplitude of heart rate decelerations was significantly higher in stage I compared with stage II (-19.36 +/- 1.44 versus -14.38 +/- 1.55 beats per minute, respectively). There were more fetal body movements during stage II than stage I (12.39 +/- 2.8 versus 9.72 +/- 2.0), but the difference was not statistically significant. CONCLUSION: Based on numeric analysis of FHR records, our data suggest that short-acting donors of nitric oxide can be administered safely to patients with pregnancy-associated hypertension.

Adult↗
PubMed2003

Ruptured membranes at term: randomized, double-blind trial of oral misoprostol for labor induction.

OBJECTIVE: To determine if oral misoprostol can replace oxytocin for labor stimulation in women with ruptured membranes at term and without evidence of labor. METHODS: Nulliparous women at 36 to 41 weeks with a singleton, cephalic-presenting fetus and ruptured membranes without evidence of labor were randomized to receive oral misoprostol (100 microg) or a placebo every 4 hours for a maximum of two doses. Intravenous oxytocin was initiated if active labor had not ensued within 8 hours of the initial study drug dose. RESULTS: Fifty-one women were randomized to oral misoprostol and 51 women to the placebo. Misoprostol reduced the use of oxytocin stimulation of labor from 90% to 37% (P <.001) and was associated with approximately a 7-hour shorter elapsed time in the labor unit. Uterine hyperactivity, defined as six or more contractions in 10 minutes without fetal heart rate decelerations, occurred in 25% of women randomized to misoprostol. However, uterine hyperactivity associated with fetal heart rate decelerations occurred in only three (6%) women, none of whom required emergency cesarean delivery. Route of delivery and infant outcomes were not related to misoprostol use. CONCLUSION: Oral misoprostol (100 microg) given in a maximum of two doses 4 hours apart significantly reduced the use of oxytocin in the management of women with ruptured membranes without labor at term.

Administration, Oral↗
PubMed1998

Newborn acid-base status and umbilical cord morphology.

OBJECTIVE: To assess the relation between umbilical cord morphology and intrapartum fetal status and umbilical cord blood gases at birth. METHODS: In a prospective study of 134 consecutive newborns and their umbilical cords, relations were investigated between umbilical cord morphologic characteristics (umbilical cord length, number of vascular coils, coiling index, and vessel length index) and intrapartum fetal heart rate (FHR) decelerations, color of amniotic fluid, operative delivery for suspected fetal acidosis, umbilical vessel blood gases, and acid-base status. RESULTS: Statistically significant linear correlations were found between umbilical venous pH and the umbilical cord length (r = 0.30; 95% confidence interval [CI] 0.13, 0.46; P < .001), number of vascular coils (r = 0.27; 95% CI 0.10, 0.43; P = .001), coiling index (r = 0.15; 95% CI 0, 0.33; P = .05), and vessel length index (r = 0.30; 95% CI 0.13, 0.46; P < .001). Statistically significant negative linear correlations were found between the umbilical venous partial pressure of carbon dioxide (PCO2) and cord length (r = -0.34, 95% CI -0.49, -0.17; P < .001), number of vascular coils (r = -0.30, 95% CI -0.46, -0.13; P < .001), coiling index (r = -0.17, 95% CI -0.34, 0; P = .03), and vessel length index (r = -0.34, 95% CI -0.49, -0.17; P < .001). The umbilical artery pH was related to vessel length index and to the number of umbilical vascular coils (r = 0.17, 95% CI 0.03, 0.36; P = .04 and r = 0.17, 95% CI 0.02, 0.35; P = .047, respectively). No relation was found between umbilical cord indices and intrapartum FHR decelerations, meconium staining of the amniotic fluid, or mode of delivery. Placental weight also correlated with umbilical cord length and vessel length index (95% CI 0.15, 0.46; P < .001 and 95% CI 0.05, 0.38; P = .01, respectively), but not with the number of umbilical cord coils or the coiling index. CONCLUSION: Umbilical venous pH and PCO2 and umbilical artery pH are related to umbilical cord morphology. Associated variations in placental morphology or placental blood flow affecting maternal-fetal gas exchange may explain these findings.

Acid-Base Equilibrium↗
PubMed1999

Predictive value of electronic fetal monitoring for intrapartum fetal asphyxia with metabolic acidosis.

OBJECTIVE: To determine the predictive value of each fetal heart rate (FHR) variable and of patterns of FHR variables for fetal asphyxia during labor. METHODS: This matched case-control study included an asphyxia group of 71 term infants with umbilical artery base deficit greater than 16 mmol/L and a control group of 71 term infants with umbilical artery base deficit less than 8 mmol/L. Each FHR record available for the 4 hours before delivery was scored in 10-minute cycles for each FHR variable. Selected patterns of important FHR variables were examined during the last hour before delivery for their predictive value for fetal asphyxia. RESULTS: The FHR variables associated with fetal asphyxia included absent and minimal baseline variability and late and prolonged decelerations. Fetal heart rate patterns with absent baseline variability were the most specific but identified only 17% of the asphyxia group. The sensitivity of this test increased to 93% with the addition of less specific patterns. The estimated positive predictive value ranged from 18.1% to 2.6%, and the negative predictive value ranged from 98.3% to 99.5%. CONCLUSION: A narrow 1-hour window of FHR patterns including minimal baseline variability and late or prolonged decelerations will predict fetal asphyxial exposure before decompensation and newborn morbidity. Thus, with careful interpretation, predictive FHR patterns can be a useful screening test for fetal asphyxia. However, supplementary tests are required to confirm the diagnosis and to identify the large number of false-positive patterns to avoid unnecessary intervention.

Acidosis↗
PubMed1999

The relationship between diastolic function of the left ventricle and QT dispersion in patients with myocardial infarction.

Lack of synchronicity concerns not only the electrical but also the mechanical function of the left ventricle and causes impaired ventricular filling. To our knowledge a direct association between electrical dispersion and impairment of left ventricular filling has not been reported. The study group comprised 71 patients with myocardial infarction. Echocardiographic Doppler studies and QT dispersion measurements from standard 12-lead electrocardiograms were performed during the second week of hospitalization. The study population was divided into high, intermediate and low QT dispersion groups. Differences in the left ventricular filling parameters between high and low QT dispersion groups were assessed. Patients with high QT dispersion had larger end-diastolic volume (134+/-31 vs. 107+/-19 ml; P=0.049) and tended to have shorter E-wave deceleration time (155+/-18 vs. 175+/-20 ms; P=0.056) compared with patients with low QT dispersion. There was a negative correlation between E-wave deceleration time and QT dispersion (r=-0.248; P=0.05). We conclude that greater dispersion of repolarization is accompanied by changes in the left ventricular diastolic geometry and more 'restrictive' filling. The hypothesis that left ventricular filling abnormalities are caused by increased electrical dispersion deserves further study, especially under controlled, experimental conditions.

Aged↗