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Biomedical subjects

J M Mallion

Publications and source records attributed to J M Mallion.

At least 145 records · Page 8Linked to original sources
PubMed1990

Day and night blood pressure values in normotensive and essential hypertensive subjects assessed by twenty-four-hour ambulatory monitoring.

Circadian blood pressure variations were studied in 110 normotensive (blood pressure less than or equal to 140/90 mmHg) and 142 untreated essential hypertensive (blood pressure greater than or equal to 160/95 mmHg) subjects. Measurements were carried out under full ambulatory conditions by the oscillometric method, using an automatic device (SpaceLabs 5200). Readings taken between 9.00 a.m. and 7.00 p.m. were defined as daytime values (activity), and those taken between 11.00 p.m. and 7.00 a.m. as night-time values (sleep). Blood pressure was significantly higher during the day than at night. The day-night differences were significantly higher in the hypertensive than in the normotensive subjects. There was a significant correlation for both systolic blood pressure (SBP) and diastolic blood pressure (DBP) between the day-night differences and DBP values at rest. The difference between the normotensives and hypertensives was smaller when the day-night difference was calculated as a percentage of the daytime blood pressure, but the SBP difference remained significantly higher in the hypertensives. The number of subjects without a nocturnal blood pressure decrease or with a decrease of less than 5-10 mmHg was not statistically different between the normotensives and the hypertensives. These results are a contribution towards an understanding of day-night blood pressure differences in hypertensive and in normotensive subjects. A knowledge of the 24-h blood pressure profile in the individual patient is important because abnormal profiles may be linked with various etiologies responsible for dysregulation, and might have prognostic implications.

Adult↗
PubMed1990

[Reproducibility at 3 different points of the pulse wave velocity at rest].

UNLABELLED: The study was aimed to search in which site the pulse wave velocity (PWV), is the most reproducible at rest, and determine the best site for measurement. The 3 sites habitually employed carotid-femoral (CF), femoral-dorsalis pedis (FP), subclavian-radial (SCR) were studied twice running at 24 hours interval (D1/D2) at rest after 10 minutes in dorsal decubitus, in 20 borderline hypertensive subjects (mean age 50 +/- 14), treated (n = 7) or non-treated (n = 13). Pulse transit time (dt) was measured with a continuous doppler velocimeter according to the ECG, the PWV calculated from the artery length on each site (dl) according to the formula PWV = dl/dt (m/s). STATISTICAL ANALYSIS: Wilcoxon test for paired series and correlation coefficients. Whatever the site, no significant difference between measurements 24 hours apart. For each measurement, the variability and standard errors at each site appear greater for CF and FP (24%), than for SCR (14%). Study of the correlations between measurements at each site: the measurements SCR and CF are correlated (r = 0.43, p less than 0.05); those at the other sites are independent of each other. CONCLUSION: at rest and 24 hrs apart in the hypertensive subject, the PWV is reproducible in the three measurement sites. The CF and FP sites give less consistent results. The SCR site seems to be the most practical: it is the site of BP measurement, it is correlated with the CF site, and its variability and standard error are low.

Adult↗
PubMed1989

[Hypertension and stress tests].

Stress tests have been performed for a long time in patients with coronary disease. The study of blood pressure variations, under these circumstances, is also interesting in hypertension. Several types of stress tests, dynamic and static, may be performed. Dynamic tests on ergometric bicycles are the most frequently performed. The evolution of the BP during stress increases regularly and there is a linear correlation between the BP values and the level of work as well as the heart rate (HR). It is therefore possible to individualize a reference blood pressure profile, according to age and sex. The stress may find applications from a diagnostic, prognostic and therapeutic standpoint. First of all, in borderline HT, the stress test enables to confirm the HT and better differentiate between hyperemotional and hyperkinetic patients. In severe hypertension, the stress test permits to better define the magnitude of the haemodynamic disorder. In true hypertensive patients, undergoing major physical stress (work, sports...) the stress test permits to evaluate the tolerance to stress and the faculties of myocardial adaptation. From a prognostic standpoint, the incidence of permanent hypertension is 2 to 3 times higher in patients presenting an abnormal blood pressure profile. There is a significant correlation between the BP at maximum stress and the left ventricular mass index at all stages of the HT. The stress test makes it possible to better define the mode of action of antihypertensive medications, prescribe a personalized treatment according to these patients reactivity to stress and guarantee the correction of blood pressure abnormalities, since normalisation at rest does not necessarily imply a normalisation during stress.

Blood Pressure Determination↗
PubMed1989

Twenty-four-hour ambulatory blood pressure in shift workers.

Blood pressure and heart rate of 15 male shift workers were measured every 15 minutes for 24 hours during three work shifts: morning, 4:00 AM to noon; afternoon, noon to 8:00 PM; and night, 8:00 PM to 4:00 AM. For each shift, 24-hour systolic and diastolic blood pressure showed a large "trough" (the low pressure span) and a continuous range of elevated pressure (the high pressure span). Fourier series were used to model the 24-hour blood pressure profiles. A careful examination of the residuals (measured minus predicted pressures) showed that four harmonics were necessary to describe the data accurately. The model enabled localization in each blood pressure profile of the high and low pressure spans that did not coincide with the subject's work and rest periods. The time and slope of blood pressure entering and leaving these spans could also be individually determined. Mean blood pressure during the high pressure span was the same for the three shifts, but mean blood pressure during the low pressure span was lower when the subject worked in the afternoon. During that shift, the systolic blood pressure slopes entering and leaving the low pressure span were steeper than during the two other shifts. The high pressure span was longest during the night shift and shortest during the afternoon shift. Therefore, a change in the working time profoundly perturbed the 24-hour blood pressure profile.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Arterial pressure--self measurement. Recommendations. French Society for Arterial Hypertension--the Measurement Group].

Self-measurement of blood pressure has become widespread in recent years. It may be defined as the measurement of arterial pressure by a conscious and free-willed subject. Self-measurement must remain a medical procedure, which means that doctors should be able to advise their patients (a) on the type of apparatus they should purchase and get validated at regular intervals; (b) on the method of using the apparatus in practice, and (c) on the circumstances, conditions and numbers of measurements to be performed. Doctors must remain responsible for the interpretation of the results obtained and for the diagnostic, pronostic an therapeutic applications of the method. Self-measurement of blood pressure naturally has advantages and disadvantages, but it must be noted that it may offer an alternative to hospitalization or to ambulatory arterial pressure measurement, avoid excessive or defective therapies and improve the patient's compliance with his treatment.

Blood Pressure Determination↗
PubMed1989

[Determination of physiologic disturbances due to rotating shift schedules using ambulatory measurement of the arterial pressure].

UNLABELLED: Technological progress has led to the creation of jobs requiring minimal physical labor, high mental concentration, and rotating shift schedules. This study evaluates the physiological effects of rotating shift work on the cardiovascular system. METHODS: blood pressure (BP) and heart rate were recorded automatically (Spacelabs) under ambulatory conditions over a 24 h period in 15 quality control technicians at a chemical factory, during each one of their 3 shifts: morning (4 am-12 noon), afternoon (12 noon to 8 pm) and night (8 pm to 4 am). RESULTS: mean Bp and HR did not differ significantly between the 3 shifts when the work period was taken into account. (table; see text) Activity appears to prevail over circadian rythm and to determine BP and HR levels. Techniques using chronological series analysis which take BP variability into account (Fourier harmonic transformations) show that night work considerably modifies the modes of BP and HR variation (going to sleep, waking-up, variability at work). CONCLUSION: BP and HR measurement provide a pratical approach to the analysis of physiological disturbances induced by rotating shift work in employees with mentally demanding jobs.

Adult↗
PubMed1989

[Course in time of the blood pressure profile in effort].

Blood-pressure (BP) responses to exercise are worth studying to evaluate the cardiovascular adjustment ability of hypertensive subjects whose daily activities include important physical performances. Some authors also consider that they have a predictive value. Changes in exercise BP over a period of more than 3 years (mean: 5.2 +/- 2.26 years) were studied in 225 subjects, some of whom had normal BP while others had untreated borderline or moderate hypertension. Globally, the mean values of diastolic pressure, heart rate, exacerbated response and BP profile remained remarkably stable with time despite significant differences in some groups of subjects. When each subject was considered separately, a normal BP response to exercise had a very high predictive value, since systolic and diastolic pressure which were normal at the first examination remained normal at the second examination in 85 p. 100 and 93 p. 100 respectively of the subjects. The reproducibility with time of response to exercise is an additional incentive to perform this type of examination.

Adult↗
PubMed1989

[Arterial compliance during exertion in hypertensive and normal subjects of the same age].

In order to improve the reproducibility of arterial compliance measurements, normally taken at rest, we performed these measurements during exercise under stable conditions. Our aim was to determine, in both normotensive and hypertensive subjects, those parameters which condition changes in arterial compliance during exercise, and in particular age, systolic/diastolic arterial pressures and heart rate. The study involved 59 normotensive and 31 hypertensive subjects. Compliance was evaluated by measuring pulse wave velocity in the upper limbs at three levels of exercise: 50, 75 and 100 watts. Pulse wave velocity measured in different age-groups gradually increased at each exercise level, but age made no significant difference in values. Only one correlation appeared at recovery, with a significant (p less than 0.05) difference between normotensive and hypertensive subjects. As regards arterial pressures, there was only one correlation with diastolic pressure reflecting an increase in mural tension during exercise. A correlation with heart rate appeared during exercise, probably due to the vasomotor effect of a higher adrenergic tone. The diversity of vascular repercussions and haemodynamic regulation modes during exercise accounts for the variability of arterial compliance measurements taken during exercise, irrespective of age and blood pressure level. However, these measurements remain of interest for their reproducibility and their correlation with the adrenergic tone. This may be useful for the choice of an antihypertensive therapy.

Adult↗
PubMed1989

[Value of the measurement of pulse wave velocity during exertion].

Establishing an arterial compliance index by measuring pulse wave velocity (PWV) has proved useful for the early diagnosis of arterial lesions in atherosclerosis and diabetes, but the lack of reproducibility of this measurement when performed at rest has limited its use. Exercise tests, a global method for the dynamic study of blood pressure (BP) level, has been suggested as a means of standardizing the neurosensorial influences on the vasomotor tone. In this paper, we advocate a dynamic evaluation of arterial compliance by measurement of PWV during exercise, and we report the results of our study concerning the reproducibility of PWV during exercise, and we report the results of our study concerning the reproducibility of PWV measurements and the changes observed in arterial compliance during dynamic constraints. Thirty normotensive subjects aged from 20 to 30 years were studied on two occasions separated by more than 24 hours. PWV was measured in the subclavian and radial arteries by doppler shifted ultrasound combined with ECG, both at rest and after 3 levels (50, 75, 100 watts) of a standard triangular exercise test in sitting position. BP levels during exercise were the same in both tests. The reproducibility of PWV measurements in these two tests confirmed the non-reproducibility of these measurements at rest. It also showed that reproducibility is obtained during the first minutes of exercise (r = 0.72 ; p less than 0.001 at 75 watts). Changes in PWV at exercise varied with the subject, with a mean progressive increase of 1 m/s/level (rest = 9.8, 50 w = 11.1, 75 w = 12.2, 100 w = 13.14; 4 min. later: 10.7 m/s).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Non-invasive ambulatory blood pressure measurement over 24 hours: effects of labetalol on the rise of blood pressure in the early morning].

Three french specialist centers have included 19 hypertensive patients in an open cooperative study of the effect of labetalol (L = 200 to 400 mg b.i.d.) on the 24 hour blood pressure (24 h - B.P.) recording by a non invasive method (Spacelabs - Squibb Medical Systems), with a particular assessment of the early morning rise of BP. Each patient was subjected to 2 assessments at the end of a 14 days' placebo period and of a 28 days' treatment period. At the end of the study, the systolic (SBP) and diastolic (DBP). B.P. were significantly decreased at rest (p less than 0.001) and on the 24 hours recording (p less than 0.001). The reduction of B.P. was also significant on day period from 7 a.m. to 22 p.m. (p less than 0.001) and night period from 22 a.m. to 7 a.m. (p less than 0.05) as well as on the early morning period, 3 hours before and after waking (p less than 0.001). The heart rate was significantly reduced during the day (p less than 0.05) and was not on the night. The slope of the early morning rise of B.P. was marked after placebo and significantly decreased after labetalol with a reduction of 52% for SBP and 49% for DBP (p less than 0.001). These results show that labetalol has an antihypertensive effect over 24 hours with a marked effect on the early morning rise of B.P.

Adult↗
PubMed1988

[Evaluation of the importance of ambulatory blood pressure measurement in the diagnostic and therapeutic management of hypertension].

PURPOSE: evaluate, in a Public Health approach, the contribution of ambulatory blood pressure recordings (ABPR) in the diagnostic and therapeutic management of hypertension. METHODS: a retrospective study is led among 32 physicians who have addressed 473 patients for ABP: 182 for borderline hypertension (B-H) diagnosis, 94 for treatment decision (NT-H) and 197 for a therapy efficiency assessment (T-H). ABPR is performed with the non invasive Spacelabs device on a 24 hour period. The data interpretation is provided by statistical comparison of patient's data with those of a same age and sex 30 normotensive subjects group. RESULTS: The table presents the action of physician according to the ABPR motive and answer: TT = therapy, NT = no therapy, ADJ = adjustment, NADJ = no adjustment. (Table: see text). CONCLUSION: physicians follow drastically ABPR interpretation: a large number of patient avoid a treatment (68 percent of B-H group and 63 percent of NT-H group), the therapy is modified for 40 percent of the T-H patients. Such evidence may have some Public Health implications.

Adult↗
PubMed1988

[Does the blood pressure balance obtained in hospitalized hypertensive patients remain satisfactory a month later at home? (Ambulatory measurement)].

Twenty patients with hypertensive heart disease have been hospitalised for adjustment of their antihypertensive medication. The new treatment was left unchanged during a period of forty days, the survey consisted in three blood pressure measurements at rest every day during the first ten days of hospitalisation and an ambulatory blood pressure measurement the 10th and 40th day. The 10th day, there is no significant correlation between blood pressures measured at rest and ambulatory, even if the average BP levels are not significantly different. The 40th day, the average BP levels are equivalent with a correlation coefficient of 0.5 for the systolic and 0.64 for the diastolic blood pressure (p less than 0.01). Thus, a measurement of the ambulatory BP at the 10th day of hospitalisation seems to be a good indicator of the expected long term therapeutic effect. However, absence of greater increase of the ambulatory BP at one month probably corresponds with the majored action of certain treatments as time goes by.

Adult↗
PubMed1988

[Reproducibility and development of pulse wave velocity at rest and during exertion].

PURPOSE: to search in which situation the PWV is the most reproducible. METHODOLOGY: PWV is measured with a continuous doppler technique along the subclavial radial arterial segment on the right forearm. 30 normotensive subjects (20-30 years) are studied twice running at 24-hour interval at rest and during stress (ergometric bicycle, stress levels: 50, 75, 100 watts/mn). STATISTICS: Student test and correlation when the data are normally distributed. RESULTS: mean PWV increases progressively with blood pressure during stress. REST: 10.0, 50W: 11.3, 75W: 12.33, 100W: 13.32, 4 mn rest: 10.6. Mean differences (MD) with standard deviations (SD) and correlation (COR) are as following: (Table: see text). If we take into consideration MD, SD and COR between the 2 stress tests, 75W level appears to be the most reproducible. CONCLUSION: these data must be taken into account when using PWV to appreciate the vascular effect of some medications especially in hypertension.

Adult↗
PubMed1987

[Arterial pressure and shift work activities].

Circadian blood pressure (BP) and heart rate (HR) variations are studied during activities and sleep in a group of nine subjects with shiftwork activities (3 X 8 hours with a short rotation of 2 days). BP and HR values are measured in ambulatory (outside the hospital) with and automatic device (Spacelab system 5,200) during 24 hours at 3 times according to the work periods (morning 7-12 AM, afternoon 3-11 PM, night 1-7 AM) on a month. According to BP hour variations, activities and sleep are the main determining factors. For work periods BP mean values are significantly lower during night than during day. The lower BP values are found during the sleep periods, but the values are higher when subjects sleep during the day. There is an adaptation according to work hour changes, but this adaptation is incomplete and during night activities, the circadian rythm is partly altered. These constatations must be taken in account particularly on a therapeutic point of view for hypertensive subjects for which the treatment must be adjusted.

Adaptation, Physiological↗