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At least 1,405 records · Page 78Linked to original sources
PubMed2000

Influence of dose per fraction and overall treatment time on the response of pulmonary micrometastases of the R1H-tumour to fractionated irradiation.

BACKGROUND AND PURPOSE: Macroscopic subcutaneously growing R1H-tumours have been shown to respond almost independently of the dose per fraction when treated under ambient conditions. In addition decelerated repopulation during fractionated irradiation has been shown for this experimental tumour. The aim of the present study was to investigate whether this is also the case for pulmonary micrometastases which are assumed to be fully oxygenated or whether differences in the oxygenation status of the tumour possibly alters its response to fractionation. The influence of the dose per fraction and overall treatment time on the response of micrometastases to fractionated irradiation was studied. MATERIALS AND METHODS: Pulmonary metastases were induced by i.v. injection of viable tumour cells. Treatment was started 14 days later, when metastases reached an average size of four cells. Total doses of 16 to 28 Gy were administered within an overall treatment time of 11 or 25 days, using doses per fraction of 1, 2, or 4 Gy. Tumour response was quantified by metastatic control (MCD(37%)). RESULTS: Fractionation had a significant influence on local control (P=0.009). After application of 1, 2, or 4 Gy and an overall treatment time of 11 days the MCD(37%) was 25.4 (95% C.I.: 21.5-32.0) Gy, 20.7 (17. 0-24.0) Gy, and 18.5 (14.9-21.6) Gy, respectively. When overall treatment time was prolonged to 25 days the MCD(37%) increased to 25. 5 (21.3-33.5) Gy when fractions of 2 Gy where applied, but this difference was not significant (P=0.13). The doubling time of 12.8 days determined for the metastatic clonogenic tumour cells during fractionated irradiation was significantly longer than the 4.1 days observed for untreated metastases (P=0.006). CONCLUSIONS: The results show a strong influence of fractionation on treatment outcome and a decelerated repopulation during fractionated irradiation treatment for well oxygenated pulmonary metastases of the R1H-tumour.

Animals↗
PubMed1998

Cardiac response induced by voluntary self-paced finger movement.

Cardiac responses induced by slow and brisk voluntary self-paced index finger movements of the dominant and non-dominant hand were investigated in a group of 12 right-handed subjects. Since subjects synchronised movement and respiration, initiating movement preferably during inspiration, a novel method of evaluating the movement-induced cardiac response was used. This method allows one to distinguish the differential effects on the cardiac response due to movement and respiration. The effect of type of movements (slow vs. brisk) and hand (right vs. left) were analysed. Slow movements induced a monophasic cardiac response, consisting of cardiac deceleration preceding and accompanying movement. Brisk movements induced a biphasic cardiac response, consisting of preparatory deceleration followed by slight post-movement cardiac acceleration. Hand-dominance did not influence the movement-induced cardiac response. The results suggest that neocortical structures involved in planning and execution of voluntary movement impinge upon brainstem cardiovascular nuclei. Vagal cardiac outflow is affected and gives rise to movement-induced changes in cardiac chronotropism.

Adult↗
PubMed1999

Voluntary movements and event-related potentials in Parkinsonians (stages 1-2).

The temporal analysis of goal-directed movements has revealed that the delay of movement initiation in Parkinsonians might be decreased or abolished by altering the preparatory set and increasing the motivation level of patients. Averaged event-related potentials (ERPs) during different psychomotor reactions to light stimuli, ignore condition and difference waves between attend (reactions) and ignore conditions were analyzed in 19 Parkinsonian patients (stages 1-2) and 12 healthy subjects. A deceleration of psychomotor reactions in the patients was found to be accompanied by a decrease in ERPs, especially in frontal recording. This decrease was affected by an altered pre-stimulus preparatory set in the patients. The decrease of endogenous ERPs (difference waves) was associated to a greater extent with the motor acts than with cognitive operations. The deceleration of the voluntary movements in Parkinsonism is assumed to be connected with 'deficit' of the frontal activation due to a dysfunction of the basal ganglia.

Adult↗
PubMed1998

Effects of memory load on event-related patterns of 40-Hz EEG during cognitive and motor tasks.

The present study describes a phasic event-related synchronization (ERS) in the gamma band (36-44 Hz) induced by the onset of probe visual stimuli. The experiment consisted of two experimental tasks with high and low memory-load in which a geometrical figure (S1) was held in memory for comparison with a subsequent stimulus (S2). In each task a Go-NoGo paradigm was used with a Same-Different discrimination task. The aim of the study was to examine the influence on 40-Hz ERS of stimulus type ('Same-Different') and of response (Go-NoGo) task as moderated by activation or effort level (high/low memory-load). The investigation was carried out in 27 women. The EEG was recorded from FP1, FP2, F3, F4, P3, P4, O1 and O2 scalp sites referenced to linked earlobes. As a manipulation check for activation level, we recorded heart rate (HR) during the S1-S2 period. A main peak of activity was found around 160 ms with a maximum at occipital sites. The amplitude of this peak was higher in the high memory-load as compared to the low memory-load condition. This difference was manifested mainly at F3 and O2 scalp sites. A larger 40-Hz peak at F3 was also found in the Go compared to the NoGo condition. No 40-Hz ERS differences between Same and Different trials were observed. The HR was found sensitive to the stimulus type showing a greater HR deceleration response to S2 for Same trials, as compared to Different ones. In parallel with 40-Hz ERS response, the HR deceleration was more pronounced for the high memory-load as compared to the low memory-load condition. The results indicate that the 40-Hz ERS is dependent upon both memory-load and motor responding. The influence of memory load on cognitive (Same-Different) and motor response (Go-NoGo) variables is discussed.

Adult↗
PubMed2002

Stability and skill in driving.

Two experiments addressed the relation between postural stability, perceptual sensitivity, and stability of driving performance. A vehicle was fitted with differential GPS for measuring position and speed, position sensors for measuring brake and accelerator depression, force transducers for measuring door, console and footrest bracing forces, and an accelerometer for measuring the 3D accelerations of the vehicle. In Experiment 1, we investigated whether the initiation of deceleration and the control of braking might be due to sensitivity to the perceptual variable tau, which specifies time-to-contact (TTC), and in particular, whether its first derivative, tau-dot, is used to maintain a constant deceleration profile. Using both untrained experienced drivers (EDs) and trained driving instructors from the Holden Performance Driving Centre (HPDC), results confirmed that, regardless of skill level, tau-dot was maintained at a value close to 0.5 and, as predicted by Lee [Perception 5 (1976) 437], braking was initiated when TTC approximately 5 s. In Experiment 2, we wished to quantify the purported differences in driving behaviour between EDs and HPDC instructors during a variety of everyday manoeuvres. Results indicated that instructors utilised a different cornering trajectory, a different emergency braking strategy, and were able to perform a high-speed swerve and recovery task more effectively than the EDs. In general, the instructors applied greater bracing forces using the door and console compared with EDs. The instructors also applied greater footrest forces during emergency braking than did the EDs. The greater use of bracing by instructor drivers to resist g-forces represents a strategy of active stabilisation that enhances both postural stability, as well as overall stability and consistency of driving performance. Results are discussed with regard to the dynamics of perceptual-motor coordination, and how increased stability might improve sensitivity to relevant perceptual information. We conclude that driver-training programmes that focus on increasing driver stability (as a pre-requisite for increased control) show great promise as a means to improving one's attention during driving, and hence have the potential to dramatically improve road safety in general.

Adult↗
PubMed2002

[Geriatric drug therapy guide: evaluation of the effect on prescription at old people's homes in Gipuzkoa].

OBJECTIVE: To analyse the impact of the composition, publication and dissemination of the Geriatric Drug-therapy Guide of Gipuzkoa (GDGG) and monitoring of adherence to it, as an intervention in the community to improve medical prescription in old people s homes (OPH) in Gipuzkoa. DESIGN: Descriptive evaluation < > the intervention. SAMPLE: billed prescriptions for pharmaceutical products (PP) from Osakidetza in 1996 (pre-intervention) and 1997-1999 (post-intervention). SOURCE: the prescription data base of the Basque Government. SETTING: 35 OPH in Gipuzkoa (2963 residents). MEASUREMENTS AND RESULTS: Indicators: Adherence percentage=(No. units prescribed of PP with selected active principles)x100/total No. PP prescribed); Mean price per unit (MPU)=(total RSP of units/total No. PP units). Overall adherence rose from 44% in 1996 to 62% in 1999; the groups accounting for 84% of prescription and the sub-groups accounting for 65% of prescription went up in these years from 43% to 64% and from 50% to 67%, respectively. A deceleration of the increase in MPU in OPH was detected, when compared with the figure for primary care. CONCLUSIONS: Overall adherence to the GDGG is high, with an upwards tendency that lasts about three years after the initial intervention. Similarly, the evolution of the MPU for the PP prescribed in OPH is better than the primary care average, with a steady deceleration in the indirect indicator analysed. The community intervention undertaken is an effective tool for improving medical prescription in the old people s homes examined.

Aged↗
PubMed1998

Left ventricular mass and diastolic function in normotensive young adults with autosomal dominant polycystic kidney disease.

Left ventricular hypertrophy is often found very early in the course of autosomal dominant polycystic kidney disease (ADPKD). Diastolic dysfunction has been shown in hypertensive adult patients with ADPKD with increased left ventricular mass (LVM), but there are no data about diastolic function in the young ADPKD population without hypertension and with normal renal function. To evaluate very early alterations in cardiac structure and diastolic function in young normotensive patients with ADPKD, color Doppler echocardiography was performed in 46 young normotensive patients with ADPKD and 35 healthy subjects. LVM, transmitral pulsed Doppler flow (diastolic function), and valvular abnormalities were studied. Patients with ADPKD showed higher LVM indices (LVMIs) than controls (89.7+/-17.3 v 68.5+/-17.2 g/m2; P < 0.0001). Peak early diastolic velocity (E wave) deceleration time and isovolumic relaxation time were significantly prolonged in patients with ADPKD compared with controls (E wave deceleration time, 182.5+/-51.3 v 149.4+/-34 msec; P=0.002; isovolumic relaxation time, 97.7+/-17.5 v 79+/-15 msec; P=0.0001). No differences were found in valvular abnormalities in the two groups. In conclusion, young normotensive patients with ADPKD showed increased LVMIs and Doppler abnormalities consistent with early diastolic dysfunction.

Adolescent↗
PubMed1998

[A simplified method of continuous-wave Doppler noninvasive assessment of ventricular relaxation in mitral insufficiency].

INTRODUCTION AND OBJECTIVES: The minimum value of dP/dT is a parameter of diastolic function that can be estimated noninvasively by analyzing the profile of velocity of the mitral regurgitant jet, recorded by continuous-wave Doppler. This estimation requires a complex analysis of the curves that impedes its practical use. Our objective was to validate a simplified method to estimate noninvasively the value of dP/dTmin when mitral regurgitation exists. We calculated the pendient of the profile of velocity of the curve of mitral regurgitation during its deceleration, between 3 and 1.5 m/s, an interval that defines a difference in pressure using the formula delta p = (4v2(1) - 4v2(2)). We divided this interval by the time needed by the jet to decelerate from 3 to 1.5 m/s, obtaining the rate of pressure decay, in mmHg/s. METHODS: We provoked mitral regurgitation in five pigs and registered dP/dT and the curve velocity of mitral regurgitation simultaneously, by micromanometer-tipped catheter and continuous-wave Doppler, respectively. The rate of pressure decay was calculated on the mitral regurgitation curve. RESULTS: We obtained 29 simultaneous registers. The coefficient for the correlationship between dP/dT and the rate of pressure decay was with an r value of 0.62 (p < 0.0001). The rate of pressure decay underestimated systematically the value of dP/dT. Intra and interobserver variability of TDP was 9 and 11%, respectively. CONCLUSIONS: This study validates a simplified method to estimate dP/dT noninvasively, with acceptable correlation with invasive measurements and adequate reproducibility.

Animals↗
PubMed2004

Effect of electromagnetic field emitted by cellular phones on fetal heart rate patterns.

The study was planned to determine the effects of electromagnetic fields produced by cellular phones on baseline fetal heart rate, acceleration and deceleration. Forty pregnant women undergoing non-stress test were admitted to the study. Non-stress test was obtained while the subjects were holding the CP on stand by mode and on dialing mode, each for 5 min. Similar recordings were taken while there were no phones around for 10 min. Electromagnetic fields produced by cellular phones do not cause any demonstrable affect in fetal heart rate, acceleration and deceleration.

Adult↗
PubMed2002

Blunt renal trauma: biomechanics and origination of renal lesions.

OBJECTIVES: Computer-assisted simulation of trauma is supposed to improve protective systems in traffic and risky leisure activities. In case of blunt renal injury biomechanical data being concerned with kidneys as a whole are extremely sparse. To enable three-dimensional simulations this study should supply important data of the renal biomechanics and elucidate the relationship between force distribution and origination of renal lesions. MATERIALS & METHODS: The present study investigated 66 isolated uninjured porcine kidneys using a drop impactor. Changes in deformation, brake force of power, deceleration and intrapelvic pressure are depicted while varying energy application between 1.4 and 14.2J. Lesions were detected by cross-dissecting the organs into slices. RESULTS: The measured values reflect a high correlation between load energy or brake force of power and deformation. Except the intrapelvic pressure all biomechanical parameters rise under increasing energy load. Comparing the different parameters over time a simultaneous concurrence of maximum brake force of power, deceleration and intrarenal pressure can be shown, the peak of deformation was reached belatedly. CONCLUSIONS: The paths of biomechanical curves prove a viscoelastic behaviour of the kidney. In contrast to the literature the region principally bearing the load seems to be the collision zone between renal pelvis and cortex where first lesions appear. This is mainly caused by the fluid filled pelvis, an incompressible support, that is supposed to change its shape after exceeding energy application of about 4J.

Animals↗
PubMedDate not supplied

Improvement of the mass resolution of the atom probe using a dual counter-electrode.

As compared to other techniques, the mass resolution of the 3D atom probe is rather poor. This low mass resolution derives from the spread in energy of field-evaporated ions. In this work, the single counter-electrode used to remove atoms from the specimen was replaced with a dual counter-electrode. A positive standing voltage V(PA) is applied on the electrode facing the specimen while the second electrode is grounded. As a result, ions experience a post-acceleration between electrodes that lowers energy deficits of ions resulting in an improvement in the mass resolution. This paper reports the study of the resulting improvement in mass resolution as a function of the post-acceleration voltage. It is also shown that, because of the evaporation pulse, ions also undergo a dynamic post-deceleration in the between electrodes. This post-deceleration contributes to the mass resolution increase. Our results show that this very simple device makes it possible to significantly improve the mass resolution of the atom probe. For a low post-acceleration voltage, the mass resolution is 800 FWHM and 200 at full-width tenth-maximum.

Journal Article↗
PubMed1998

Patterns of bursting occurring in thalamic cells during parkinsonian tremor.

It has been proposed that parkinsonian tremor is produced either by the activity of an intrinsic thalamic pacemaker or by the oscillation of an unstable long loop reflex arc. The former (central) hypothesis proposes that overactivity of neurons in the internal segment of the globus pallidus inhibits or hyperpolarizes thalamic neurons. When hyperpolarized, thalamic cells oscillate with bursting of the type associated with low threshold calcium spikes (low threshold spike-bursts). Low threshold spike-bursts can be identified by particular patterns of interspike intervals within the burst. The alternative (peripheral) hypothesis proposes that tremor results from oscillation of a reflex arc transmitting activity from muscle stretch receptors to thalamus, motor cortex, and back to the stretched muscle. When the gain of this reflex is increased, the arc may become unstable and oscillate. Oscillations produced by peripheral inputs may produce an acceleration-deceleration pattern within the burst which results in sinusoidal modulation of a spike train if bursting is periodic. We have assessed these two hypotheses by studying the pattern of interspike intervals occurring within bursts recorded in patients with parkinsonian tremor. The spike trains were analysed for 118 cells located in the ventral nuclear group including ventralis intermedius (thalamic cerebellar relay nucleus, n=48) and ventralis oralis posterior (thalamic pallidal relay nucleus, n=39) of patients with parkinsonian tremor. Two cells recorded in ventralis intermedius of a sleeping patient with chronic pain showed bursting activity similar to the low threshold spike-bursts recorded in sleeping animals, suggesting a common mechanism for low threshold spike-bursts across species. Forty-two cells recorded in patients with parkinsonian tremor (ventralis intermedius, n=19; ventralis oralis posterior, n=12) were classified as tremor-related cells because their activity was characterized by both a concentration of power at tremor frequency and significant correlation with tremor. Eleven tremor-related cells, 10 located in ventralis intermedius or ventralis oralis posterior and most responding to sensory inputs, had an acceleration-deceleration pattern of intraburst firing. Only one cell, a tremor-related cell in ventralis intermedius, showed the pattern expected of presumed low threshold spike-bursts. Therefore, intraburst interspike interval patterns consistent with either the central or the peripheral hypothesis were recorded in the thalamus of patients with parkinsonian tremor. Twenty-one tremor-related cells (15 cells in ventralis intermedius or ventralis oralis posterior) had bursts with intraburst interspike intervals which were independent of position of the interspike interval within the burst. Therefore, the activity of the majority of cells was not consistent with either hypothesis, suggesting that another oscillatory process may contribute to parkinsonian tremor.

Electromyography↗
PubMed1978

Falls from heights.

Falls from heights are most commonly due to accidents in children and suicide, accident, and crime-related incidents in adults. Two types of injury result from falls from heights: injury resulting from direct impact and deceleration-type injury. The injuries resulting from direct impact are mostly fractures. The body position at impact is crucial. The deceleration forces immediately post-impact result primarily in visceral and internal injury, including cranial injury. There is a lack of correlation between os calcis fractures and vertebral fractures. Spinal cord injury is infrequent. Survival figures are higher than usually assumed.

Accidental Falls↗
PubMed2003

Acute increase of umbilical artery vascular flow resistance in compromised fetuses provoked by uterine contractions.

BACKGROUND: An impaired placental circulation is involved in the mechanism of late fetal heart rate (FHR) decelerations. OBJECTIVES: To explore umbilical artery (UA) Doppler velocimetry changes in response to uterine contractions during the oxytocin challenge test (OCT) and assess the potentially clinical value of 'OCT Doppler velocimetry'. METHODS: 111 women with pregnancy complications were subjected to an OCT with simultaneous recordings of FHR and UA pulsatility index (PI). Positive OCT cases (late FHR decelerations) were compared with negative OCT cases (normal FHR patterns). Only negative OCT cases were allowed a trial of vaginal delivery. RESULTS: The UA PI was higher in OCT positive (N=21) than in negative cases (N=90) during uterine contractions and relaxations (P<0.05), but not during basal measurements. A positive OCT, but not negative, was associated with an increase of PI during contractions and relaxations compared with basal measurements (P<0.05). Fetal growth restriction (N=58), operative delivery for fetal distress (ODFD) in labor (N=10), and birth asphyxia (N=8) were not associated with PI changes significantly different from cases without these complications. CONCLUSIONS: During uterine contractions and relaxations, but not during basal measurements, a significantly higher UA PI evolved in OCT positive cases compared with OCT negative cases. This indicates a pathophysiological mechanism disclosed only during uterine activity. Although these changes would not have been revealed by traditional Doppler velocimetry, the data suggest a limited predictive value of 'OCT Doppler velocimetry' on the short-term neonatal outcome.

Adult↗
PubMed1997

Clinical features of and cardiotocographic findings for premature infants with antenatal periventricular leukomalacia.

OBJECTIVE: To clarify the clinical features of and cardiotocographic findings for premature infants with antenatal periventricular leukomalacia (PVL). METHODS: Antenatal PVL was judged to be present if a cyst greater than 3 mm in largest diameter was detected in the periventricular region by the 14th day of life on cranial ultrasonography. The clinical features of and cardiotocographic findings for 12 premature infants with antenatal PVL born within 1 year were compared with those of 12 infants chosen as control group matched in gestational age at birth from the premature infants without antenatal PVL born within the study period. RESULTS: Abnormalities of the umbilical cord such as coiling, excessive torsion and membrane insertion were observed more frequently for infants with antenatal PVL (58.3%) than for control infants (16.7%) (P<0.05). Frequent moderate variable deceleration on the fetal cardiogram was also observed more frequently for infants with antenatal PVL (80.0%) than for control infants (27.3%) (P<0.05). CONCLUSION: Abnormalities of the umbilical cord and frequent moderate variable deceleration on fetal cardiotocogram appear to be causes of antenatal PVL in premature infants.

Apgar Score↗
PubMed1999

The acute effects of sublingual estradiol on left ventricular diastolic function in normotensive and hypertensive postmenopausal women.

AIM: limited information is available on estrogen influences on diastole. We aimed to investigate the acute effects of a single dose of sublingual 17beta-estradiol on left ventricular diastolic function in postmenopausal women. METHODS: the study included 28 women aged 55.6 +/- 6 (15 normotensive and 13 hypertensive), who underwent Doppler echocardiography and estradiol plasma levels determination before and 60 min after sublingual administration of 4 mg of 17beta-estradiol. RESULTS: there were no modifications in heart rate. Both systolic and diastolic blood pressure dropped significantly in the hypertensives and remained unchanged in normotensives. Estradiol levels were 1790 +/- 869 pg/ml in the normotensives and 2664 +/- 1490 in the hypertensives (P < 0.05). Peak early velocity, in the population as a whole, increased from 84 +/- 18 to 91 +/- 18 cm/s and the early-to-atrial velocity ratio from 1.1 +/- 0.4 to 1.4 +/- 0.6 (P < 0.0001 for both). Both acceleration and deceleration rates increased significantly (P < 0.0001). These changes were shared by all the patients. In addition, the hypertensive patients, who presented a baseline pattern characterized mainly by a grossly increased peak atrial velocity with reduction in the early-to-atrial velocity ratio, demonstrated a decrease in peak atrial velocity from 92 +/- 12 to 78 +/- 10 cm/s (P < 0.0001), associated with significant reductions in deceleration time (P < 0.0001) and pressure half time (P < 0.005). Therefore, the typical picture of impaired ventricular relaxation was favorably changed after estradiol administration. CONCLUSIONS: the sublingual administration of estradiol induces acute modifications in left ventricular diastolic function in postmenopausal women, with improvement in the age-related left ventricular relaxation pattern, and that these beneficial changes are more pronounced in hypertensive that in normotensive women.

Administration, Sublingual↗
PubMed2000

Early changes in left ventricular function in chronic asymptomatic alcoholics: relation to the duration of heavy drinking.

OBJECTIVES: This study sought to assess preclinical cardiac abnormalities in chronic alcoholic patients and possible differences among alcoholics related to the duration of heavy drinking. BACKGROUND: Chronic excessive alcohol intake has been reported as a possible cause of dilated cardiomyopathy. However, before the appearance of severe cardiac dysfunction, subtle signs of cardiac abnormalities may be identified. METHODS: We studied 30 healthy subjects (age 44 +/- 8 years) and 89 asymptomatic alcoholics (age 45 +/- 8 years, p = NS) divided into three groups, with short (S, 5-9 years, n = 31), intermediate (I, 10-15 years, n = 31) and long (L, 16-28 years, n = 27) duration of alcoholism. Transmitral early (E) and late (A) Doppler flow velocities, E/A ratio, deceleration time of E (DT) and isovolumic relaxation time (IVRT) were obtained. Left ventricular (LV) wall thickness and volumes were also determined by echocardiography, and LV mass and ejection fraction (EF) were calculated. RESULTS: The alcoholics had prolonged IVRT (92 +/- 11 vs. 83 +/- 7 ms, p < 0.001), longer DT (180 +/- 20 vs. 170 +/- 10 ms, p < 0.01), smaller E/A (1.25 +/- 0.34 vs. 1.40 +/- 0.32, p < 0.05), larger LV volumes (73 +/- 8 vs. 65 +/- 7 ml/m2, p < 0.001 for end-diastolic volume index; 25 +/- 4 vs. 21 +/- 2 ml/m2, p < 0.001 for end-systolic volume index), higher LV mass index (92 +/- 14 vs. 78 +/- 8 g/m2, p < 0.001) and thicker posterior wall (9 +/- 1 vs. 8 +/- 1 mm, p < 0.001). Ejection fraction did not differ between the two groups (66 +/- 4 vs. 67 +/- 2%). Deceleration time of the early transmitral flow velocity was longer in groups L (187 +/- 18 ms) and I (185 +/- 16 ms) compared with group S (168 +/- 17 ms, p < 0.001 for L and I vs. S), whereas A was higher in group L compared with S (43 +/- 10 vs. 51 +/- 10 cm/s, p < 0.005). Multiple regression analysis identified duration of heavy drinking as the most important variable affecting DT and A. CONCLUSIONS: Left ventricular dilation with preserved EF and impaired LV relaxation characterized LV function in chronic asymptomatic alcoholic patients. It appeared that the progression of abnormalities in LV diastolic filling related to the duration of alcoholism.

Adult↗
PubMed2000

Evolving changes in Doppler mitral flow velocity pattern in rats with hypertensive hypertrophy.

OBJECTIVES: The aim of our study was to explore evolving changes in a mitral flow velocity pattern (MFVP) and its hemodynamic and pathological correlates in hypertensive rats in an isolated diastolic heart failure model. BACKGROUND: Development of left ventricular (LV) hypertrophy and concomitant diastolic dysfunction cause heart failure in hypertensive hearts even with normal systolic function; however, associated evolving change in MFVP is still unclear. METHODS: Mitral flow velocity pattern was recorded every 2 weeks from 7 to 19 weeks in six hypertensive rats. Hemodynamic and pathological correlates of Doppler mitral flow indexes were examined as an additional part of the study using the hypertensive rats at the age of 13 weeks (compensatory stage, n = 7) and at 19 weeks (heart failure stage, n = 8). RESULTS: Initial development of pressure overload LV hypertrophy resulted in a decrease in early diastolic filling wave (E), a reciprocal increase in the filling wave due to atrial contraction (A) and prolongation of deceleration time of E wave (relaxation abnormality pattern). These changes were associated with an increase in tau, an index of LV relaxation, but without a change in LV end-diastolic pressure. Transition to congestive heart failure caused an increase in E, a decrease in A and shortening of deceleration time. These changes were not associated with further increase in tau but with elevation of LV end-diastolic pressure, reflecting marked LV hypertrophy and myocardial fibrosis. CONCLUSIONS: Development of pressure overload LV hypertrophy is associated with evolving changes in MFVP from normal to relaxation abnormality pattern and, in turn, to pseudonormalized to restrictive pattern. Analysis of MFVP may be useful to follow not only functional but also constitutional changes of the myocardium in hypertensive hearts.

Animals↗