Biomedical subjects

C Schwebel

Publications and source records attributed to C Schwebel.

5 recordsLinked to original sources

PubMed1994

[Left ventricular hypertrophy and blood pressure variability during rest and ambulatory monitoring in the hypertensive patient].

To study the relationship between assessment of blood pressure (BP) variability measured by continuous measurement (Finapres) or discontinuous ambulatory (ABPM Spacelabs) in 70 untreated essential hypertensive subjects (mean age 51 +/- 12) and their relationship with the development of left ventricular hypertrophy (LVH). There is no relationship between the BP variability measurements either by Finapres nor by ABPM. Multiple regression analysis show that ambulatory systolic BP variability (standard deviation) and resting BP variability (spectral analysis of SBP in the medium frequency band 0.1 Hz) are related to LVH index when we take into account age and BP difference (to explain LVH) (p < 0.001) ABPM SBP variability increase with LVH, while resting SBP measurement of BP variability (Mayer waves) significantly decreased. The study points to the different role of BP variability measurements in the mechanisms related to left ventricular hypertrophy and to the interest of continuous BP resting spectral analysis measurements.

Blood Pressure↗

PubMed1993

[Delayed potentials and left ventricular hypertrophy].

Delayed potentials (DP) (ECGHA) are markers of the occurrence of ventricular rhythm disturbances, and have a prognostic value after myocardial infarction. In hypertensive heart disease, the prevalence of DP is variable according to the literature (1-40%) and their prognostic significance is not known. We examine the frequency of DP in hypertension (HT) and the relationship between DP and left ventricular hypertrophy (LVH) as defined by echocardiographic estimation of the LV mass index (LVMI). We investigated 50 consecutive patients with essential HT who were being assessed as regards cause and effects of HT. Exclusion criteria were coronary artery disease, bundle branch block and poor echocardiographic trace. ECGHA was registered by means of ART device. The presence of DP as defined according to the criteria of Kacet. LV mass was determine according to the method of Penn and LVH defined according to the criteria of Devereux. Besides LVMI, were examined age, sex, duration of HT, micro-albuminuria, LVH on ECG (Sokolow index and strain-ECG). There were no correlations between the different variables studied and the presence of DP. The results relating to LVMI are shown in Table. There were no correlation between DP and LVH on echography. Other explanations, electrophysiologic, ischemic and histological may explain the greater incidence of BP observed in hypertensive heart disease. [table: see text] The prevalence of DP was not significantly different as regard the presence or absence of LVH (35% vs 25%; p = 0.53). In the 10 patients with the highest LVMI, the DP were enregistered 3 times.

Action Potentials↗

PubMed1993

[Relationships between ambulatory blood pressure and carotid artery diseases].

UNLABELLED: We studied in a retrospective study 138 consecutive hypertensive patients, the relationship between atherosclerosis lesions in carotid-artery and the ambulatory blood pressure. Only 93 of the 138 patients were finally included in this study because of the quality of information. They were 50 women and 43 men, aged 57.2 +/- 12.6 years. METHODOLOGY: The ambulatory blood pressure was recorded by oscillometric method (Spacelab monitor). The carotid artery were studied by echography and doppler. RESULTS: Carotid lesions in hypertensive patients didn't differ significantly when ambulatory systolic blood pressure increased (147,1 mmHg vs 145.2 in the day, and 135.5 mmHg vs 131.7 in the night; ns); Ambulatory diastolic blood pressure was lower during the day when carotid lesions where present (86.5 mmHg vs 93.2; p < 0.05). Ambulatory diastolic blood pressure decreased also with age; Ambulatory pulsed blood pressure increased when carotid lesions where present (59.3 mmHg vs 52.8 in the day and 58 mmHg vs 51.7 in the night; p < 0.05). Ambulatory pulsed blood pressure increased also with age and body mass index. CONCLUSION: This results suggest a predictive character of the pulsed pressure measure on the existence of carotid artery lesions in hypertensive patients and that a non invasive study of the carotid artery is opportune when pulsed pressure ambulatory measure is high.

Aged↗

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↗