Biomedical subjects

F Tremel

Publications and source records attributed to F Tremel.

44 records · Page 3Linked to original sources

PubMed1992

Use of ambulatory blood pressure monitoring in the management of antihypertensive therapy.

The recent development of ambulatory blood pressure (ABP) monitoring techniques has improved recording of blood pressure in therapeutic trials and in the clinical setting. The application of ABP differs according to which of these 2 applications is being considered. In therapeutic trials, a placebo control is required. The large quantity of precise data acquired with ABP monitoring allows the study of a limited number of patients; it also allows individual study of patients with a 'white coat' response (i.e. elevated blood pressure in response to examination by the clinician). Analysis of data from ABP monitoring may include the following: comparison of mean blood pressure values over 24 hours, daytime or night-time, or over any other selected time period; 24-hour blood pressure profiles, or analysis hour-by-hour, giving true chronotherapy, and providing data regarding the wearing-off of a drug effect or loss of therapeutic control; analysis of blood pressure at particular times, such as on waking; or specific examination of nonresponders. In individual patients, ABP monitoring should be reserved for specific indications. It can be used before initiation of treatment to confirm the necessity for treatment, especially in the context of hypertension at rest or the 'white coat' effect. With established treatment, ABP monitoring can be used in patients with resistant hypertension, in severe hypertension to examine loss of blood pressure control over time or inversion of the day/night cycle, and in patients with a specific illness, e.g. diabetes, in order to obtain the lowest blood pressure readings possible. Examination of these factors assists clinicians to accurately decide upon the timing and frequency of antihypertensive therapy.

Blood Pressure Monitors↗

PubMed1992

[Evaluation of norepinephrine content in the myocardium in hypertensive patients with left ventricular hypertrophy].

The sympathetic nervous system seems to be a non hemodynamic factor involved in the development of hypertension and in left ventricular hypertrophy determinism. The aim of this study was to estimate the myocardial norepinephrine content in essential hypertensive patients, using a reliable radio-iodinated marker of norepinephrine: the 123I-meta-iodobenzylguanidine (123I-meta-iodobenzylguanidine). Eight male and female hypertensive patients with left ventricular hypertrophy and average age of 52 +/- 9 years underwent a resting, ambulatory and effort blood pressure measure. Echocardiographic parameters allowed measure of left ventricular mass index (according to Devereux, and we considered left ventricular hypertrophy as left ventricular mass index greater than 120g/m2. Plasma norepinephrine is measured at rest. Cardiac and mediastinal radioactivity is detected 4 h after a 4mCi i.v. injection of 123I-meta-iodobenzylguanidine and meta-iodobenzylguanidine myocardial uptake is definite as the cardiac/mediastinal ratio (N:1.78 +/- 0.19). Meta-iodobenzylguanidine-myocardial uptake average value of hypertensive patients was 1.89 +/- 0.19 (1.63 to 2.25) without statistical difference to control subjects. We found a significative correlation between meta-iodobenzylguanidine myocardial uptake and effort systolic blood pressure variation in one hand, and with heart rate increase with effort in the other hand. There is no correlation between meta-iodobenzylguanidine-myocardial uptake and left ventricular mass index or ambulatory blood pressure. In hypertensive patients with left ventricular hypertrophy, meta-iodobenzylguanidine myocardial uptake is normal or high, in agreement with experimental data in SHRs, model of human essential hypertension. Therefore myocardial scintigraphy with 123I-meta-iodobenzylguanidine can appreciate cardiac norepinephrine content in humans.

3-Iodobenzylguanidine↗

PubMed1992

[Action of labetalol on norepinephrine myocardial content in left ventricular hypertrophy in hypertensive patients].

The high incidence of cardiovascular morbidity and mortality in hypertensive patients with left ventricular hypertrophy shows the great interest in understanding the pathophysiology of this process. Many reports suggest the role of catecholamines in generating left ventricular hypertrophy. The aim of this study is to evaluate the effect of labetalol on myocardial norepinephrine content in hypertensive subjects with left ventricular hypertrophy by using an isotopic norepinephrine marker, the 123I-meta-iodobenzylguanidine (123I-MIBG). Eight male and female hypertensive patients with left ventricular hypertrophy were investigated after a 30 day placebo period. Resting, ambulatory and effort blood pressure was measured. Echocardiographic parameters allowed measure of left ventricular mass index according to Devereux. And we considered left ventricular hypertrophy as left ventricular mass index greater than 120 g/m2. Cardiac and mediastinal radioactivity is detected 4 h after a 4 mCi i.v. injection of 123I-MIBG and MIBG myocardial uptake is definite as the cardiac/mediastinal ratio (N : 1.78 +/- 0.19). All subjects received at the beginning of the study (D0) 2 tablets of labetalol 200 mg, increased to 4 tablets if diastolic blood pressure during follow-up remained above 95 mmHg. Patients again underwent these explorations after 3 months of treatment (D90). Labetalol decreases in considerable manner MIBG myocardial uptake as it has been shown that it decreases tissular norepinephrine content in experimental studies. Therefore, MIBG myocardial uptake seems to be a reliable tool in evaluating drugs effect on cardiac sympathetic nervous system.

3-Iodobenzylguanidine↗

PubMed1992

[Methods of computerized approach of dysautonomia from a non-invasive pressure signal].

OBJECTIVE: examination of an automated exploration of autonomic neuropathy using the Ewing score and evaluation of sympatho-vagal tone. MATERIAL: continuous non-invasive collection of blood pressure (BP) data by means of Finapress fingerprobe. The signal was analysed after digitization at 500Hz, sampled and computerised. Values of systolic BP (SBP), diastolic BP (DBP) and heart rate (HR) are analysed by Anapres (Notochord). PROTOCOL: the pressure monitor is placed on the finger and the reading calibrated to the BP value recorded by auscultatory method on the contralateral arm to give a gap of less than 10 mmHg. BP and HR response to five different manoeuvres are recorded, namely: at rest over 7 minutes, after lying decubitus for 15 minutes; on rising suddenly over 3 seconds, and then over 9 minutes standing still; during 2 respiratory manoeuvres (a) deep breathing over 6 cycles per minute, (b) Valsalva pressure at 40 mmHg sustained over 20 seconds; isometric exercise with sustained handgrip at 30% maximal force sustained over 3 minutes. ANALYSIS: a dedicated computer programme displays in graphic form BP and HR over each manoeuvre and allows the operator to locate the exact cut-off of normality for each test of the Ewing score and also measure the balance of sympatho-vagal tone by Fourier transformation of the interval data of HR or BP peaks. APPLICATION: this approach allows evaluation of autonomic function and sympatho-vagal tone by means of 40 minutes of clinical testing and two minutes of automated analysis. This approach seems useful in the assessment of the autonomic nervous system in diabetes.

Autonomic Nervous System Diseases↗

PubMed1991

[Study of the 24 hour blood pressure profile in normotensive type I diabetic patients].

A number of studies have shown changes and even an inversion of the diurnal cycle in certain affections: Cushing's syndrome, pheochromocytoma, severe renal failure, autonomous nervous system disorders, pre eclampsia etc.... The authors studied diurnal and nocturnal variations of blood pressure in type I diabetics. Twenty-nine normotensive (WHO criteria) type I diabetics (NTD) average age 34.9 +/- 11 years, with diabetes of 13.6 +/- 8 years standing, and 118 normotensive non-diabetics (NT) aged 20 to 60 years (distributed by decennies according to age and sex) were studied. The systolic (SBP) and diastolic blood pressures (DBP) were recorded at rest in the decubitus position by the phase V indirect auscultatory method and during ambulatory monitoring (automatic Spacelabs no. degrees 90207 device) every 15 minutes during the daytime and 20 minutes during the night. The mean values were studied; the values of the heart rates were identical in the NTD and NT populations. Significant difference in SBP between the Nt and NTD were recorded: during daytime there was no difference either in SBP or DPB; during the night, there was a significant difference in SBP. A study of the day-night differences both in absolute and in relative values (day-night difference with respect to daytime values as a percentage) did not show any statistically significant differences between the two populations. Abnormalities of the 24 hour profile, defined as absence of a 5 mmHg fall in nocturnal BP values, were looked for but there were no differences between the NT and NTD subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

[Nyctohemeral changes of blood pressure. Diagnostic and prognostic value].

The blood pressure shows circadian variation in normal subjects with higher diurnal than nocturnal values: the difference between day and night time blood pressure is about 10-20 mmHg for systolic and for diastolic blood pressure. These variations are mainly related to physical and/or psychosensorial stress: the physician is himself a cause of increased blood pressure (the "white coat" effect). The degree of the nocturnal decrease in blood pressure which is maximal 2 and 3 o'clock is related to the quality and depth of sleep. The nocturnal decrease is followed by an increase in blood pressure when the person wakes up (early morning peak). Diagnostic signs: a physiological inversion of the circadian rhythm may be observed in people who sleep during the daytime and work at night. There would seem to be less of a nocturnal fall in black persons in the United States. Some pathological conditions can inverse or at least disturb the ciacadian variation: apart from hypertension, this has been reported in autonomic nervous system disease, in diabetics with autonomic neuropathy in some elderly patients, in Cushing's syndrome, after cardiac transplantation, etc... In hypertensives, the lack of nocturnal decrease of the blood pressure or an inversion in circadian rhythm should be looked for in severe and secondary hypertension such as associated with pheochromocytoma, or in renal dialysis patients. In toxaemia of pregnancy, this abnormality may herald an eclamptic crisis. Prognostic signs: in normotensives (especially in black persons) and hypertensives, inversion of the circadian rhythm is associated with more severe left ventricular hypertrophy and a higher morbidity.

Adult↗

PubMed1991

[Analysis of results of the determination of ambulatory blood pressure].

Although there has never been a consensus about the presentation and analysis of the results of ambulatory blood pressure recordings, it is important to define the stages and useful means both for studying individual and groups of recordings (therapeutic trials): individual recordings: edition of results, 24 hour display, quantification of the blood pressure over predefined periods, comparison with reference values; therapeutic trials: verification of the quality of the recordings (consecutive hours without measurements, artefacts), preparation of the results for analysis (grouped in hourly mean values), search for confusing factors and non-adherence to the protocol, analysis of efficacy over 24 hours and predefined periods, partial studies (non-responders, normalisation of blood pressure with respect to reference values, control of efficacy over more than 24 hours...). All these stages must be predefined in the study protocol.

Ambulatory Care↗

PubMedDate not supplied

Carotid remodeling in essential hypertension: role of blood pressure, indexed parameters, and association with cardiac mass and aortic stiffness.

The role of blood pressure on carotid remodeling, using no indexed and indexed parameters, was studied in essential hypertension. Carotid parameters were also compared to cardiac mass and aortic stiffness. Forty untreated hypertensive men had echocardiography, carotid ultrasonography and carotidfemoral pulse wave velocity measurements. Cross-sectional area index was associated essentially with the 24-hour systolic blood pressure whereas intima-media thickness was related especially to the 24-hour pulse pressure. Carotid intima-media thickness and cross-sectional area indexes were less related to blood pressure variables than non-indexed parameters. There is an independent association between 24-hour pulse pressure and left ventricular mass index and pulse wave velocity. To conclude, blood pressure, particularly pulse pressure, is associated with vascular and cardiac alterations. The indexation by the body surface area do not provide any additional information in the association between carotid and blood pressure parameters.

Adult↗