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Biomedical subjects

C Marabotti

Publications and source records attributed to C Marabotti.

At least 19 recordsLinked to original sources
PubMed1997

Comparative effects of enalapril and verapamil on myocardial blood flow in systemic hypertension.

BACKGROUND: The comparative effects of calcium channel blockers and ACE inhibitors on myocardial blood flow (MBF) in hypertensive patients after long-term treatment are still unknown. METHODS AND RESULTS: Twenty hypertensive subjects with normal coronary arteries were randomly assigned to verapamil 240 to 480 mg/d or enalapril 10 to 40 mg/d. MBF was quantified at rest, during pacing tachycardia, and after dipyridamole by positron emission tomography and 13N-ammonia before and 6 months after treatment after 1 week of pharmacological washout. In both groups, blood pressure and heart rate during flow measurements were not different before and after therapy. Before treatment, mean MBF at rest, during pacing tachycardia, and after dipyridamole infusion was similar in the two groups; however, pacing and dipyridamole flows were significantly lower than those obtained in a control group of normotensive subjects. After treatment, in the enalapril-treated patients, MBF did not change in the three study conditions. In the verapamil-treated patients, MBF did not change at rest and significantly increased during pacing and after dipyridamole. The inhomogeneity of regional MBF distribution, evaluated from the coefficient of variation, decreased at rest after both treatments and, in the enalapril group, also during pacing. No relation was found between changes in MBF and changes in left ventricular mass. CONCLUSIONS: In arterial hypertension, MBF during pacing tachycardia and after dipyridamole is impaired. Successful therapy with verapamil increases MBF response to these stimuli, independent of changes in perfusion pressure and left ventricular mass. These results suggest that verapamil directly improves coronary microcirculatory function in hypertension. Enalapril does not significantly change MBF but reduces the inhomogeneity of regional flow distribution.

Antihypertensive Agents↗
PubMed1994

Diastolic function in the different patterns of left ventricular adaptation to essential hypertension.

Recent reports have shown that four distinct left ventricular anatomical patterns, with different hypertension severity and hemodynamic features, are associated with sustained arterial hypertension (normal anatomy, concentric remodeling, concentric hypertrophy and eccentric hypertrophy). The aim of this study was to evaluate left ventricular diastolic function in these different left ventricular anatomic patterns. To achieve this aim, 94 borderline-to-severe essential hypertensive patients (60 never treated before, 34 off treatment for at least 3 weeks before the study) underwent an echo-Doppler study; left ventricular thickness, dimension and mass index were obtained. Early (E) and late (A) transmitral flow velocity, their ratio (A/E) and the early filling fraction (EFF) were obtained by pulsed-wave Doppler and used as left ventricular diastolic function indexes. Differences between groups were evaluated by one-way ANOVA followed by Scheffe F-test. A normal left ventricular anatomy was found in 41 (44%), concentric remodeling in 17 (18%), concentric hypertrophy in 21 (22%) and eccentric hypertrophy in 15 (16%) patients. Early filling fraction and A/E ratio which resulted were significantly different for the groups (P < 0.001 and P < 0.002, respectively). As compared with the group with normal left ventricle, patients with concentric hypertrophy had significantly EFF and those with eccentric hypertrophy had significantly lower EFF and higher A/E ratio. Our results thus confirm the presence of distinct anatomical left ventricular adaptation patterns in arterial hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1994

Echo Doppler diastolic function and exercise tolerance.

OBJECTIVE: To investigate the possible association between Doppler left ventricular filling pattern and exercise capacity in a group of normotensives to severe hypertensive patients. BACKGROUND: Invasive left ventricular filling indexes evaluated at rest are reported to be related to exercise capacity in heart failure. Whether exercise capacity is limited by abnormalities of left ventricular filling also in other less severe conditions is however unclear. METHODS: Fifty-one subjects with normal to severely elevated blood pressure underwent a standard exercise test on cycle ergometer, negative for myocardial ischemia, and a complete echo Doppler evaluation showing a basal systolic function within normal limits. RESULTS: Basal systolic function indexes were not significantly related to exercise duration. On the contrary, exercise duration was highly significantly correlated to the relative atrial contribution to left ventricular filling (0.001 < P < 0.05), in both the overall group and the two subgroups in whom exercise was interrupted because of fatigue (n = 30) or because of attaining target heart rate (n = 21). Significant correlations were also observed between exercise time and resting blood pressure, whereas no association with resting heart rate, age and body surface area was found. Exercise time also correlated to left ventricular mass and mass index but not to left ventricular volume. Multiple regression analysis showed that exercise tolerance was significantly related to diastolic blood pressure and left ventricular filling. Echo Doppler indexes of left ventricular filling are associated with exercise duration; left ventricular diastole could thus influence effort tolerance, not only in patients with cardiac insufficiency, but also in subjects with normal to elevated blood pressure levels and normal systolic function at rest.

Blood Pressure↗
PubMed1994

Cardiac morphology and function in arterial hypertension. The effects of a new multifactorial hypotensive agent: urapidil.

It has been recognized as increasingly important to determine whether antihypertensive agents, while satisfactorily lowering the blood pressure, at the same time adversely or positively affect the cardiac hemodynamic profile. On theoretical grounds, one would expect that an ideal hypotensive drug should decrease blood pressure by decreasing total peripheral resistances, without affecting cardiac output, and should normalize left ventricular hypertrophy without deteriorating systolic or diastolic left ventricular function. We here briefly review the effects of urapidil on these variables in patients under chronic treatment investigated in a series of studies employing echocardiography. The results of the studies are in fair agreement and indicate a blood pressure decrease already after one month of treatment, due to a decrease of peripheral resistances, without changes in heart rate. A clear trend towards a reduction of cardiac hypertrophy during the treatment is suggested by the significant decrements of the indices measured. One study also suggests that right ventricular wall thickness may be reduced. Left ventricular dimensions remained unchanged in all except one study. Systolic and diastolic function indices were also unchanged during the first 6 months of treatment and, in one study, improvement was found after 12 months of treatment. Taken together these results suggest that urapidil lowers blood pressure favorably, affecting cardiac morphology and function.

Antihypertensive Agents↗
PubMed1993

Normal ultrasonic myocardial reflectivity in hypertensive patients. A tissue characterization study.

Ultrasonic backscatter of myocardial walls is directly related to the morphometrically evaluated collagen content in humans. The integrated backscatter is also increased in hypertrophic cardiomyopathy, whereas it gives normal values in the physiological hypertrophy of elite athletes. We assessed the quantitatively evaluated myocardial reflectivity in 46 mild to moderate, clinically uncomplicated essential hypertensive patients, with echocardiographically assessed normal regional and global left ventricular function, and 22 age- and sex-matched normotensive control subjects. With an echo prototype implemented in our institute, we performed an on-line radiofrequency analysis to obtain quantitative operator-independent measurements of the integrated backscatter signal of the ventricular septum and posterior wall. The integrated values of the radiofrequency signal of myocardial walls were normalized for those of the pericardial interface and expressed as a percent (integrated backscatter index). Hypertensive patients and control subjects differed in mean blood pressure (119 +/- 11 versus 95 +/- 5 mm Hg, p < 0.001) and left ventricular mass index (134 +/- 31 versus 105 +/- 21 g/m2, p < 0.001). However, integrated backscatter index overlapped for both the septum (28 +/- 17% versus 25 +/- 6%, p = NS) and the posterior wall (13 +/- 7% versus 13 +/- 4%, p = NS). In the hypertensive group, there was no detectable correlation between septal integrated backscatter index and either septal thickness (r = -0.26, p = NS) or mean arterial pressure (r = -0.14, p = NS). Hypertensive patients showed a normal pattern of quantitatively assessed ultrasonic backscatter, even in the presence of left ventricular hypertrophy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Regional myocardial blood flow and coronary reserve in hypertensive patients. The effect of therapy.

Patients with essential arterial hypertension demonstrate abnormal vasodilator capacity either during increased cardiac metabolic demand or during pharmacological vasodilation. Structural and functional damage to the coronary microcirculation has been proposed as one of the major causes of impaired coronary reserve in this disease. To assess the role of microvascular impairment in regional myocardial blood flow (MBF), 27 patients with essential hypertension were evaluated by dynamic positron emission tomography (PET) at rest, during atrial pacing and after dipyridamole infusion and compared with 13 healthy subjects. All patients had normal coronary arteries, 17 had moderate to severe hypertension and 10 had mild hypertension. Baseline mean MBF of 0.97 +/- 0.25 ml/min/g was significantly increased to 1.60 +/- 0.38 during atrial pacing and 2.35 +/- 0.95 after dipyridamole infusion (p < 0.01); however, mean flow during atrial pacing and after dipyridamole infusion was significantly lower than in healthy subjects (2.15 +/- 0.73 and 3.71 +/- 0.86 ml/min/g, p < 0.05 and p < 0.01, respectively). The MBF response to atrial pacing and dipyridamole infusion was similarly depressed in patients with mild and severe hypertension. The study was repeated after 6 months of antihypertensive treatment with the calcium antagonist verapamil or the angiotensin converting enzyme (ACE) inhibitor enalapril in a subgroup of 20 patients as part of a randomised, single-blind clinical trial. This study is still in progress; the initial 16 patients treated with verapamil or enalapril showed an obvious improvement in MBF values during atrial pacing and after dipyridamole infusion after 6 months of therapy (mean MBF: 2.10 +/- 0.64 and 2.99 +/- 1.63 ml/min/g, respectively, p < 0.05 vs pretreatment values). In conclusion, obvious impairment of MBF during atrial pacing and after dipyridamole infusion was observed in hypertensive patients with normal coronary arteries and this appeared unrelated to the severity of hypertension. Therapy with verapamil or enalapril improved coronary reserve and MBF response to an increase in myocardial oxygen demand.

Adult↗
PubMed1992

[Relationship of Doppler indexes of left ventricular filling and exertion tolerance].

The aim of this study was to evaluate if Doppler indexes of left ventricular filling are related to exercise capacity. Since a correlation between left ventricular filling pattern and causal blood pressure has been recently reported along a wide range of pressure values, a group of subjects with blood pressure ranging from normal to severely elevated values was studied. Twenty-four subjects (11 normotensives, 13 mild to severe hypertensive patients) underwent an echo-Doppler study and a maximal multistage cycloergometric exercise test. Since the cycloergometric test was limited by fatigue or dyspnea in all subjects, exercise duration was used as an effort tolerance index. Echocardiographic indexes of systolic function resulted normal in all subjects. Significant relationships with exercise duration were found for several indexes of left ventricular filling (A peak: r = -.743, p < .0001; A/E ratio: r = -.606, p < .005; early filling fraction: r = .639, p < .001). Exercise time was also significantly related to casual blood pressure, both systolic and diastolic. The relationships between transmitral blood flow and exercise capacity seem to indicate that an impairment of ventricular relaxation (as indicated by the progressive increase of atrial contribution) is associated with a decreased exercise tolerance, possibly because a progressively lower activation of Frank-Starling mechanism. Diastolic function thus seems to be able to affect exercise tolerance even in subjects with normal systolic function and blood pressure ranging from normal to severely elevated values.

Adult↗
PubMed1991

Electrocardiographic signs of atrial overload in hypertensive patients: indexes of abnormality of atrial morphology or function?

Left atrial electrocardiographic (ECG) abnormalities have been reported as common findings in hypertension; however, their relationships with atrial anatomy are still uncertain. In addition, in arterial hypertension several studies demonstrated an abnormal left ventricular filling. The aim of this study was to investigate the relationships of the ECG signs of left atrial abnormality to atrial anatomy and left ventricular filling as evaluated by pulsed-wave (PW) Doppler in a group of patients with uncomplicated essential hypertension. To this end, 53 untreated essential hypertensive patients (age 44 +/- 8 years; blood pressure 160.5 +/- 21.5/104.7 +/- 13.5 mm Hg) underwent a complete 12-lead ECG and a PW Doppler study of the transmitral flow velocities. The ECG criteria of left atrial abnormality were: P wave wider than 0.12 (or 0.10) second or higher than 0.25 mV in lead II; P wave/PR segment ratio (Macruz index) greater than 1.6 in lead II; and P wave terminal forces in lead V1 equal to or more negative than 0.04. Echocardiographic measurements were made according to American Society of Echocardiography (ASE) convention. Doppler parameters of left ventricular filling were measured as E and A peak velocity, A/E ratio, and the ratio between the velocity-time integral under the E peak and that of the whole diastolic flow, which represents the rapid filling fraction (RFF). At least one ECG sign of atrial abnormality was present in 34 patients (64%); the Macruz index gave the most common ECG index of atrial abnormality (31 patients).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Casual, ambulatory and stress blood pressure: relationships with left ventricular mass and filling.

In arterial hypertension, casual blood pressure seems to be weakly related to the level of cardiac involvement. The aim of the present study was to assess if blood pressure during ambulatory monitoring, and during different stress tests, is a stronger predictor of anatomical and functional changes observed in hypertensive heart disease. To this aim, 29 untreated patients with borderline-to-moderate essential hypertension underwent an echo-Doppler evaluation to determine left ventricular thickness and mass. From transmitral flow, the ratio between late and early filling velocities (A/E ratio) was used to assess left ventricular diastolic behaviour. On the same day that ultrasonic study was carried out, we also measured a set of casual blood pressures; conducted a mental arithmetic test (standardized series of mental subtractions); a handgrip test (30% of maximum voluntary contraction for 3 minutes); and performed noninvasive ambulatory monitoring of blood pressure (Spacelabs 5200). Significant relationships were observed between left ventricular mass and both night-time systolic blood pressure (r = 0.46, P less than 0.02) and peak systolic blood pressure during mental stress (r = 0.39, P less than 0.05). The A/E ratio was significantly associated with casual systolic and diastolic blood pressure (r = 0.45, P less than 0.02; r = 0.38, P less than 0.05, respectively); day-time diastolic blood pressure (r = 0.47, P less than 0.02); night-time systolic and diastolic blood pressure (r = 0.44, P less than 0.05; r = 0.42, P less than 0.05 respectively); and peak systolic blood pressure during the mental arithmetic test (r = 0.44, P less than 0.05). Our results seem to confirm the presence of a relationship between causal blood pressure and left ventricular filling. Moreover, the transmitral flow seems to be dependent on both mean levels of blood pressure on ambulatory monitoring and systolic blood pressure during mental stress. As concerns left ventricular mass, the correlations observed support the weakness of the links between blood pressure and left ventricular anatomy.

Adult↗
PubMed1991

Left ventricular filling: relationship with arterial blood pressure, left ventricular mass, age, heart rate and body build.

The relationships of age, heart rate, body build and, in particular, of arterial blood pressure and left ventricular mass to several Doppler indexes of diastolic function were evaluated in a series of 80 subjects with a wide range of blood pressure levels (106-217/68-144 mmHg). Body build and age results were inversely correlated to the indexes, reflecting the early contribution to left ventricular filling, whereas the increase in heart rate was associated with an increase in late diastolic contribution. Strong correlations (in most instances, P less than 0.0001) were observed with arterial blood pressure and left ventricular mass: the increase of these parameters was associated with a decrease of early transmitral peak velocity (E peak) and of early filling fraction, with an increase of late diastolic transmitral peak velocity (A peak) and of A:E ratio and, finally, with an increase of both deceleration time of E peak and acceleration time to A peak. Blood pressure or left ventricular mass were also confirmed as strong predictors of nearly all the Doppler-derived diastolic indexes by stepwise multiple regression analysis. When the subjects were subdivided into quintiles according to diastolic blood pressure and the average values of the five subgroups were compared, age, heart rate and body build results were similar in the quintiles while diastolic blood pressure increased stepwise by 10 mmHg. Analysis of variance showed significant differences for all the indexes of left ventricular filling except deceleration time of and acceleration time to E peak (P less than 0.05 to P less than 0.0001) and almost all the echo-Doppler indexes showed a linear trend with diastolic blood pressure and left ventricular mass.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Echo-Doppler assessment of left ventricular filling in borderline hypertension.

The aim of this study was to evaluate left ventricular anatomy and diastolic function in borderline essential hypertension. To this aim, 16 borderline hypertensive patients underwent echocardiographic and pulsed-wave Doppler evaluation. As control groups, 20 normotensive controls and 20 patients with established hypertension were evaluated by the same procedure. By the Doppler assessment of transmitral blood flow, the following indices of left ventricular diastolic function were obtained: early (E) and late (A) peak flow velocity, late to early velocity ratio (A/E), early filling fraction (EFF) and acceleration and deceleration times of early and late flow peaks. Borderline hypertensives had an interventricular septum and posterior wall thickness significantly higher than normotensives and lower than established hypertensives. As regards the diastolic indexes, borderline hypertensive patients had significantly higher A peaks (P less than .02) and A/E ratios (P = .05) and lower EFF (P less than .02) as compared to normotensive controls. No significant differences were on the other hand observed with established hypertensive patients. This resultant diastolic pattern was independent of age, as indicated by the analysis of age-matched subgroups. The presence of diastolic function changes in borderline hypertension confirms the early appearance of this kind of abnormality in hypertensive heart disease. On the other hand, the finding of increased left ventricular wall thickness in borderline hypertensives does not allow us to conclude that, as suggested by other authors, diastolic function changes in the early stage of hypertension are independent on anatomical modifications.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Reduced cardiovascular efficiency and increased reactivity during exercise in borderline and established hypertension.

In this study, exercise capacity was evaluated in patients with borderline and established, uncomplicated, essential hypertension as compared to normal subjects. To this aim, the response of blood pressure, heart rate and cardiac work to a multi-stage exercise test was investigated by analyzing the results of linear regression fitting of cardiovascular parameters (ie, heart rate, systolic blood pressure and rate-pressure product (RPP)) versus time of exercise. Compared to normal patients, both essential and borderline hypertensive patients had a shorter average duration of exercise test (ie, a decreased exercise capacity), always negative for transient myocardial ischemia. This was in spite of a mild increment of maximal RPP (+19% and +10% v normal patients, respectively). Reduction of exercise duration in borderline and established hypertensive patients was related to the higher RPP at rest (+26% and +56% related to normal patients, respectively) and to the steeper slopes (rates of increment) of heart rate systolic pressure and RPP during exercise. Interestingly, in the overall population of normal and hypertensive subjects, the slopes of heart rate and RPP were directly correlated with basal blood pressure. In conclusion, these data indicate a decreased exercise tolerance in both established and borderline hypertensive patients without documented myocardial ischemia. This abnormality, which appears to be due to a disproportional increment during exercise not only of systolic pressure but also of heart rate, could reflect abnormalities in the autonomic control of heart function.

Adult↗
PubMed1989

Different determinants of left ventricular filling in normotensive subjects and essential hypertensive patients.

The aim of the study was to evaluate the relationships between left ventricular (LV) filling and age, heart rate (HR), blood pressure (BP), and LV mass in three groups of subjects with different casual blood pressure. Twenty normotensive subjects (NT: age 39.2 +/- 7.2; BP 121.6 +/- 11.3/77.7 +/- 7.5 mm Hg), 16 borderline hypertensives (BH: age 38.6 +/- 9.2; BP 138.2 +/- 11.6/91.7 +/- 9.4 mm Hg), and 20 essential hypertensives (EH: age 44.5 +/- 8.3; BP 165.7 +/- 14.8/107.6 +/- 11.4 mm Hg) underwent 2D Echo evaluation and PW Doppler measurements of transmitral blood flow velocity. In NT, the Doppler indexes of LV filling showed significant correlations only with age and heart rate (age v E peak: r = .68 P less than .001; v A peak: r = .45, P less than .05; v A/E: r = .78, P less than .001. Heart rate v A peak: r = .78, P less than .001, v A/E: r = .74, P less than .001, respectively). Similar but weaker relationships were observed in BH. On the contrary, EH showed no significant correlations with age or heart rate, but with both systolic blood pressure (SBP), diastolic blood pressure (DBP), and LV mass (SBP v A peak: r = .49, P less than .05; v A/E: r = .68, P less than .001; DBP v E peak: r = 44, P less than .05; v A/E: r = .58, P less than .01. Left ventricular mass v E peak: r = .45, P less than .05; v A/E: r = .51, P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Seasonal influences on blood pressure in high normal to mild hypertensive range.

To investigate the seasonal influences on various arterial blood pressure measurements, 22 subjects in the high normal to mild hypertensive range were examined twice following the same protocol. In one group (13 subjects), measurements were first done in warm conditions and repeated 5-7 months later in cold conditions; in the second group (nine subjects) a reverse sequence was followed. Blood pressure was measured under casual conditions during a hand grip exercise test, mental arithmetic test, and submaximal multistage bicycle exercise test; during the following 24 hours, blood pressure was measured serially with a noninvasive ambulatory blood pressure recorder. Daily outdoor maximum and indoor laboratory temperatures were also obtained. In the cold season, significantly higher values (on the average by 5-10 mm Hg, p less than 0.01) were obtained in both groups for mean diastolic daytime blood pressure. For other measurements, a trend toward higher values in the cold season was observed in both groups, although statistical significance was not obtained in all instances. For nighttime measurements, irrespective of the seasonal sequence, lower values were observed in the second session. Significant correlations were found between the differences in the average daytime ambulatory blood pressures and the corresponding changes of daily maximum outdoor temperatures after 5-7 months. These observations indicate that arterial blood pressure may be strongly influenced by environmental temperature. This phenomenon should be taken into account both in the evaluation of the individual hypertensive patients and in the design and analysis of studies on arterial hypertension, especially when ambulatory blood pressure techniques are employed.

Adolescent↗
PubMed1988

Long-term reproducibility and evaluation of seasonal influences on blood pressure monitoring.

The aim of this study was to evaluate the long-term reproducibility and the possible seasonal influences on casual blood pressure and ambulatory blood pressure monitoring in patients with borderline or mild arterial hypertension. Two sets of measurements were performed at 6-month intervals, one set in the warm and one in the cold season, using the same protocol, consisting of measurements of casual and ambulatory blood pressures, together with the recording of outdoor temperatures. Casual blood pressure was measured by an automatic recorder and 24-h ambulatory blood pressure monitoring was performed by a non-invasive device. For the selected intervals, the reproducibility of most pressure measurements was low; in addition, casual diastolic pressure and 24-h systolic and diastolic pressures were significantly higher in the cold than in the warm season. Taken together, these findings confirm and extend the results obtained in several large-scale studies and support the importance of taking environmental temperature into account, not only in epidemiological studies but also in small-scale studies and probably even in the individual patients, especially when using integrated evaluations by ambulatory monitoring.

Adult↗