AJH
2000;13:3A– 4A
ORALS: Theme II: Congestive Heart Failure and Hypertension
DECREASED MYOCARDIAL FATTY ACID UTILIZATION IN THE ELDERLY AND IN HYPERTENSIVE LVH G. Vedala, A.M. Kates, P. Herrero, R.J. Gropler, V.G. DavilaRoman*. Washington University School of Medicine, St. Louis, MO The clinical manifestations of LVH worsen with age. Experimental models of aging suggest that this may be mediated, at least in part, by abnormalities in myocardial blood flow (MBF) and intermediary metabolism (i.e. fatty acids). Furthermore, animal models of LVH have shown a reduction in myocardial fatty acid utilization (MFAU). To determine whether abnormalities in MFAU are present in the normal elderly (E) and in patients with hypertension and LVH, measurements of MBF (ml/g/min), myocardial oxygen consumption (MVO2, mol/g/min), and fasting MFAU (mol/g/min) were measured at rest using positron emission tomography in 4 patients with hypertension and LVH (age 63 ⫾ 8; 3 male; LV mass index 106 ⫾ 13 g/m2), 6 normal elderly subjects (age 64 ⫾ 4; 4 male), and 3 normal young (Y) subjects (age 24 ⫾ 1; 3 male). All groups had normal exercise stress echocardiograms, fasting lipid and glucose levels, and were nondiabetic and nonsmokers.
The aim of this work is to study the relationships between blood pressure profile, cardiac manifestations of high blood pressure and P-III-P as an index of fibrosis. We studied hypertensives without other diseases using echocardiography (M and B mode, and Doppler), ABPM using a Spacelabs 9000, and plasma levels of P-III-P. The model ANOVA, one way, was used for the statistical analysis. The level of significance was accepted for p⬍0.01 (twotailed probabilities). The 73 hypertensives studied were divided in two subgroups: dippers (49 subjects) and non-dippers (21 subjects). The non-dipper group had an higher degree of left ventricular hypertrophy obtained by the higher measurement of the inter-ventricular septum thickness (p⬍0.01), posterior wall thickness (p⬍0.01), and an higher index of left ventricular mass (p⬍0.01) then the dippers, they also had higher levels of fibrinogen (p⬍0,01) and higher plasma levels of P-III-P then dippers (p⬍0.01). It was found a correlation between the fibrinogen, P-III-P levels and index of left ventricular mass (p⬍0,01). In conclusion, P-III-P might be a marker of tissue lesion, and fibrinogen might be a plasma marker of gravity of hypertension. This gravity can be express by the degree of left ventricular hypertrophy. Key Words: Hypertension; ABPM; P-III-P; Echocardiography
Levels of MBF, MVO2, and plasma free fatty acids were similar for all groups (p⫽NS for all). The MFAU (corrected for MVO2) in the normal elderly was lower compared with normal young (3.2 ⫻ 10⫺2 ⫾ 5.3 ⫻ 10⫺3 vs. 4.1 ⫻ 10⫺2 ⫾ 7.1 ⫻ 10⫺3, p⫽0.03, respectively), and was even lower in the hypertension and LVH patients (2.3 ⫻ 10⫺2 ⫾ 4.2 ⫻ 10⫺3, p⫽0.04 vs E and p⬍0.01 vs Y, see figure). These results demonstrate altered metabolic function in normal aging, and these alterations are even more marked in patients of similar age with hypertension and LVH. Thus, the myocardial metabolic response to aging may predispose to the clinical cardiovascular manifestations of LVH. Key Words: Left ventricular hypertrophy; fatty acid utilization; positron emission tomography
AMBULATORY BLOOD PRESSURE, PROCOLAGEN AMINO-TERMINAL POLYPEPTIDE (P-III-P) AND HEMORREOLOGYC PARAMETERS C. Moreira, P. Alcaˆntara, F. Serejo, M. Gato-Varela, V. Ramalhinho, J. Braz-Nogueira, J. Martins e Silva. Medicine I Depar. / Instituto de Bioquimica fisiolo´gica—Hosp. Sta Maria/ Faculdade de Medicina de Lisboa—Portugal © 2000 by the American Journal of Hypertension, Ltd. Published by Elsevier Science, Inc.
CYCLIC VARIATION OF MYOCARDIAL INTEGRATED BACKSCATTER SIGNAL OF THE HYPERTENSIVE CARDIOPATHY. COMPARISON WITH THE ATHLETE’S HEART V. Di Bello, R. Pedrinelli*, D. Giorgi, A. Bertini, A. Cioppi, E. Talini, J. Khabirinejad, M. Pallini, S. Precisi, L. Moretti, M.T. Caputo, G. Dell’Omo*, C. Giusti. Department of Internal Medicine and *Cardiology, University of Pisa, Italy Aim of the study is to analyze the ultrasonic backscatter myocardial indexes both as peak signal intensity and as cyclic variation in these two models of left ventricular hypertrophy and in a group of sedentary healthy controls. We have studied three groups of 10 subjects, all males of mean age (31.6⫾3.5), with comparable weight and height: athlete’s group (A) (all cyclists); hypertensive group (I) and control group (C). Hypertensives are selected on the basis of ambulatory blood pressure monitoring results, according to ISHWHO guidelines. All subjects have performed 2D-color Doppler echocardiography with a digital echograph Hewlett-Packard Sonos 5500, for the conventional analysis of left ventricular mass and function. With “Acoustic Densitometry” module implemented on HP echograph, we have analyze the ultrasonic myocardial integrated backscatter (IB) signal, sampled with a R.O.I. placed at interventricular septum and at posterior left ventricular wall level. We also have considered the systo-diastolic variation of backscatter as Cyclic Variation Index (CVIbs): Left ventricular mass is comparable between the A and I groups, by inclusion criteria, and significantly higher in comparison with group C (LVMbs: A: 154.5⫾18.7; I: 146.8⫾25.5; C: 101.4⫾12.4; 0895-7061/00/$20.00
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p⬍0.001). The end diastolic IB signal doesn’t show significant statistical differences between the three groups. While the CVIbs both at septum (A: 30.5⫾5.3; I: 13.2⫾13.1; C: 27.2⫾ 7.3; p ⬍ 0.002) and posterior wall level (A: 43.7⫾9.1; I: 16.5⫾12.1; C: 40.7⫾9.1; p ⬍ 0.001) is significantly lower in the hypertensives in comparison with athletes and controls, who are comparable. The present study confirms the physiology of left ventricular hypertrophy of the athlete’s heart, evaluated with the ultrasonic integrated backscatter tissue characterization; in the hypertensive model we have demonstrated a significant alteration of myocardial CVIbs (both for septum and posterior wall), probably expression of an alteration of intrinsic myocardial function. Key Words: Ultrasonic Integrated Backscatter; left ventricular hypertrophy; hypertension; athlete’s heart NOVEL CARDIOPROTECTIVE EFFECTS OF ENDOTHELIN RECEPTOR BLOCKADE IN DIABETEIC AND HYPERTENSIVE DIABETIC HEARTS S. Verma, E. Arikawa, L. Yao and J.H. McNeill. Faculty of Medicine, University of Calgary and Faculty of Pharmaceutical Sciences, University of British Columbia, Canada Evidence suggests that the potent vasoconstrictor-mitogen endothelin-1 (ET-1) may play an important role in the patho-
AJH–APRIL 2000 –VOL. 13, NO. 4, PART 2
genesis of cardiovascular diseases. The present study was designed to examine the contribution of this peptide towards cardiac dysfunction in diabetes and combined diabetes and hypertension. To this aim, we examined the chronic effects of bosentan (a mixed ETA/B antagonist) on isolated working heart function in (a) STZ-induced diabetic rats and (b) STZ-diabetic spontaneously hypertensive (SH) rats. LV function was assessed under conditions of increasing preload in terms ⫺dP/dt, LVDP and ⫹dP/dt. Hearts from both diabetic and SH-diabetic rats exhibited marked decreases in ⫹dP/dt, ⫺dP/dt and LVDP in response to increasing preload. Chronic treatment of STZ-diabetic rats with bosentan (100 mg/kg/day for 7 weeks) improved LVDP and ⫺dP/dt but had no effect on ⫹dP/dt. In STZ-SH (diabetic⫹hypertensive) rats, chronic bosentan treatment improved both ⫹dP/dt and ⫺dP/dt without affecting LVDP. Diabetic rat hearts exhibited enhanced coronary pressor responses to ET-1 (50 pmol/L) which were restored to control values by chronic bosentan treatment. These data reveal novel cardioprotective effects of endothelin receptor blockade in diabetic and hypertensive-diabetic rats. Key Words: Cardiac function; diabetes; hypertension; endothelin; bosentan