Simultaneous vs. sequential biventricular pacing in dilated cardiomyopathy: an acute hemodynamic study.

Aims: Simultaneous biventricular pacing improves left ventricular (LV) systolic performance in patients with dilated cardiomyopathy and intraventricular conduction delay. We tested the hypothesis that further improvements can be obtained using sequential biventricular pacing by optimizing both atrioventricular and interventricular delays.

Methods And Results: In 12 patients, LV pressure, right ventricular (RV) pressure and respective rates of change of pressure (dP/dt) were acutely measured during biventricular pacing with different atrioventricular and interventricular (VVi) intervals ranging from -60 to +40 ms.

Lacidipine and blood pressure variability in diabetic hypertensive patients.

The aim of our study was to assess the effects of lacidipine, a long-acting calcium antagonist, on 24-hour average blood pressure, blood pressure variability, and baroreflex sensitivity. In 10 mildly to moderately hypertensive patients with type II diabetes mellitus (aged 18 to 65 years), 24-hour ambulatory blood pressure was continuously monitored noninvasively (Portapres device) after a 3-week pretreatment with placebo and a subsequent 4-week once daily lacidipine (4 mg) or placebo treatment (double-blind crossover design). Systolic blood pressure, diastolic blood pressure, and heart rate means were computed each hour for 24 hours (day and night) at the end of each treatment period.

Influence of dental status on dietary intake and survival in community-dwelling elderly subjects.

Objective: to evaluate the relationships between a functional measure of dental status (FDS), the nutrients intake profile (NIP) and mortality in a community elderly population.

Design: cross-sectional analysis for FDS and NIP and a prospective study for mortality.

Setting: the central district of Brescia, northern Italy.

Time and frequency domain estimates of spontaneous baroreflex sensitivity provide early detection of autonomic dysfunction in diabetes mellitus.

Diabetic autonomic dysfunction is associated with a high risk of mortality which makes its early identification clinically important. The aim of our study was to compare the detection of autonomic dysfunction provided by classical laboratory autonomic function tests with that obtained through computer assessment of the spontaneous sensitivity of the baroreceptor-heart rate reflex (BRS) by time domain and frequency domain techniques. In 20 normotensive diabetic patients (mean age +/- SD 41.

Dental status, quality of life, and mortality in an older community population: a multivariate approach.

Objective: To evaluate the relationships between a functional measure of dental status (FDS), several variables belonging to a quality of life (QOL) profile, and mortality in an older community population.

Design: Cross-sectional analysis for FDS and QOL; 10-year prospective study for mortality.

Setting: The historical and central district of the city of Brescia, northern Italy.

Broadband spectral analysis of blood pressure and heart rate variability in very elderly subjects.

Systolic blood pressure (SBP) variability is increased and R-R interval variability is reduced in the elderly. Little is known, however, about how SBP and R-R interval variabilities change in the very elderly. More important, however, it is not known which frequency components of SBP and R-R interval variability are affected significantly.

Blood pressures other than the one at the clinic.

While assessing the cardiovascular risk of hypertensive patients, different types of blood pressure measurements can be regarded as suitable surrogate endpoints. In this context the possible role of clinic, stress, exercise, basal, home and ambulatory blood pressures is briefly discussed. The clinical value of night-time blood pressure, of the clinic-daytime blood pressure difference and of blood pressure variability is also addressed.

Effects of aging on 24-h dynamic baroreceptor control of heart rate in ambulant subjects.

The effects of aging on the dynamic modulation of baroreflex sensitivity over 24 h was assessed in eight elderly (mean age +/- SD, 63.9 +/- 3.2 yr) and in eight young (23.

Blood pressure reduction and end-organ damage in hypertension.

VALUE OF AMBULATORY BLOOD PRESSURE MONITORING: Studies that have used ambulatory blood pressure monitoring techniques have shown that the average 24-h or daytime blood pressure values are more closely related to the end-organ damage associated with hypertension than are isolated office readings. IMPORTANCE OF BLOOD PRESSURE VARIABILITY IN PROGNOSIS: More recently, blood pressure variability, measured as the overall 24-h blood pressure standard deviation, has been shown to have a significant relationship to end-organ damage in hypertensive patients. The potential clinical relevance of blood pressure variability has been strengthened in a recent prospective study.

Blood pressure variability: clinical implications and effects of antihypertensive treatment.

HYPOTHESIS ON RELATIONSHIP BETWEEN BLOOD PRESSURE VARIABILITY AND END-ORGAN DAMAGE: Several studies have shown that the cardiovascular complications of hypertension are more closely related to ambulatory 24-h or daytime average blood pressure than to office readings. A few studies have also provided evidence that in hypertensive patients, not only average ambulatory blood pressure but also the degree of blood pressure variability is significantly and independently related to the end-organ damage associated with hypertension. LIMITATIONS OF PREVIOUS STUDIES: A common limitation of previous studies is that they were based on cross-sectional or retrospective observations, so that the correlative evidence they provide does not allow the relationship between blood pressure variability and end-organ damage to be interpreted causally.

Beta-adrenergic blocking treatment and 24-hour baroreflex sensitivity in essential hypertensive patients.

We dynamically evaluated the effects of beta-blockade on the sensitivity of arterial baroreflex control of heart rate in 10 mild or moderate essential hypertensive patients in whom blood pressure was recorded intra-arterially for 24 hours in ambulatory conditions. Twenty-four-hour baroreflex sensitivity was assessed by both (1) a time-domain approach based on the calculation of the slope of the regression line between linearly related progressive increases in systolic blood pressure and pulse interval (+PI/+SBP sequences) and decreases in systolic blood pressure and pulse interval (-PI/-SBP sequences) and (2) a frequency-domain approach, ie, the ratio between the spectral powers of pulse interval and systolic blood pressure around 0.1 Hz (alpha coefficient).

Blood pressure variability and organ damage.

Several studies have now shown that hypertension-induced end-organ damage is more closely related to 24-h average blood pressure than to clinic measurements. Furthermore, the degree of variability of blood pressure during a 24-h period bears a relation to organ damage that is independent of average blood pressure value. The measurement of blood pressure variability is a complex task, however, because data from automatic ambulatory blood pressure monitoring should be interpreted with caution, especially if the interval between blood pressure measurements is more than 15 min, and different types of blood pressure variability (e.

Prognostic value of 24-hour blood pressure variability.

Objectives: Evaluation of the prognostic value of 24-h blood pressure averages and 24-h blood pressure variability.

Design: After an initial thorough clinical and laboratory evaluation which included 24-h continuous ambulatory blood pressure monitoring, a group of hypertensive patients were re-examined after an average of 7.4 years.

Spectral and sequence analysis of finger blood pressure variability. Comparison with analysis of intra-arterial recordings.

The aim of our study was to assess whether the Finapres device is able to accurately monitor not only average blood pressure values but also blood pressure variability. To examine this issue, we analyzed 30-minute recordings of finger and intra-arterial pressure simultaneously obtained at rest in 14 patients. We compared systolic blood pressure, diastolic blood pressure, mean arterial pressure, pulse interval (the reciprocal of heart rate), overall variability (standard deviation), and specific time-domain and frequency-domain components.

Spectral analysis of 24 h blood pressure recordings.

Spectral analysis of blood pressure and heart rate signals allows overall blood pressure and heart rate variabilities to be split into their different frequency components. When used to analyze 24 h discontinuous blood pressure recordings, the low sampling frequency that characterizes these devices allows only the slow fluctuations in day and night blood pressure to be adequately described by the spectral approach. Conversely, spectral analysis of continuous blood pressure recordings provides information both on fast and slow changes in blood pressure and heart rate.

Clinical value of blood pressure measurements: focus on ambulatory blood pressures.

Because clinic blood pressure values are compromised by 2 major limitations--the alerting reaction to clinic measurements and the spontaneous blood pressure variability--they have only a limited correlation with average 24-hour blood pressure values. Whether the latter should be employed routinely in substitution for, or in addition to, traditional blood pressure measurements has not yet been determined, however. To date, average 24-hour blood pressure values have been shown to correlate more closely than clinic blood pressure values with the organ damage of hypertension.

Twenty-four hour blood pressure variability: clinical implications.

Ambulatory blood pressure monitoring techniques have allowed quantification of blood pressure variations occurring over a 24 hour time. The evaluation of these phenomena has not only allowed us to investigate the mechanisms responsible for cardiovascular regulation, but it has also provided information of clinical value. In particular there is evidence that blood pressure variations are significantly related to cardiovascular complications of hypertension.

Twenty-four-hour blood pressure and antihypertensive treatment.

Normal values for 24-hour blood pressure (BP) have not been well characterized. However, it is believed that the maintenance of normal blood pressure control is a desirable feature of an antihypertensive agent. This is particularly important with respect to the drug's ability to (1) maintain circadian variation, albeit from a lower baseline, (2) lower BP throughout the 24 hours, (3) avoid the development of postural hypotension, (4) avoid decreases in BP sufficient to precipitate an ischemic event, (5) and to reduce BP variability toward the normal BP limits.

Ambulatory blood pressure monitoring.

This paper reviews the evidence that, in patients with hypertension, end-organ damage correlates more closely with blood pressure values obtained by ambulatory blood pressure monitoring than with those obtained by conventional sphygmomanometry. However, ambulatory blood pressure monitoring is not suitable for routine use in the clinical setting because of a lack of standard reference values and data regarding the prognostic significance of this method. Ambulatory blood pressure values are reproducible and this method avoids the so-called placebo effect; thus, this method is useful in clinical studies investigating the efficacy and duration of action of antihypertensive drugs.

Testing the accuracy of blood pressure monitoring devices in ambulatory conditions.

In recent years technological progress has improved the construction of ambulatory blood pressure monitoring devices. This has resulted in devices able to measure blood pressure continuously and non-invasively, and also in lighter, less noisy and more accurate intermittent blood pressure monitors. The accuracy of monitors, however, is still tested by taking blood pressure measurements at rest, and testing against intra-arterial blood pressure values, in true ambulatory conditions, is very seldom used.

Reproducibility of non-invasive and intra-arterial blood pressure monitoring: implications for studies on antihypertensive treatment.

Ambulatory blood pressure has been shown to be more reproducible than office blood pressure and thus to be more suited for studying the efficacy of antihypertensive drugs. In 34 untreated essential hypertensive subjects, we measured office and 24-h non-invasive or intra-arterial blood pressure twice over a 4-week interval; 24-h intra-arterial blood pressure was obtained by the Oxford method whereas 24-h non-invasive blood pressure was obtained by the automatic SpaceLabs 5300 device, with a 10 min (daytime) or 20 min (night-time) interval between measurements. The standard deviation of the mean difference (s.

Balanced 24-hour blood pressure control by angiotensin-converting enzyme inhibitors administered once daily.

Traditional sphygmomanometric measurements may inaccurately reflect the actual blood pressure level over a 24-h period. This is due to several factors which are known to affect cuff blood pressure readings, including the limited number of readings obtainable throughout the 24 h and the alerting reaction and pressor response induced in patients by the presence of the physician. Twenty-four-hour ambulatory blood pressure monitoring has been reported to be superior to isolated cuff blood pressure readings in the diagnostic evaluation of hypertension and in assessing the blood pressure response to treatment.