The fractal structure of cardiovascular beat-to-beat series described over a broad range of scales: Differences between blood pressure and heart rate, and the effect of gender.

The fractal characteristics of heart rate variability are usually assessed by estimating short- and long-term scale coefficients, α1 and α2, by detrended fluctuation analysis. Recently we extended this approach introducing a temporal spectrum of scale coefficients, α(τ), that describes the deviations of self-similarity from the bi-fractal model at each scale τ. Until now relatively short recordings were considered and α(τ) was characterized only for scales τ<;100 s.

Detecting sodium-sensitivity in hypertensive patients: information from 24-hour ambulatory blood pressure monitoring.

Sodium sensitivity is an important cardiovascular risk factor for which a diagnosis requires a time-consuming protocol, the implementation of which is often challenging for patients and physicians. Our aim was to assess the reliability of an easier approach based on data from 24-hour ambulatory blood pressure monitoring performed in hypertensive subjects during daily-life conditions and habitual diet. We enrolled 46 mild to moderate hypertensive subjects who underwent 24-hour ambulatory blood pressure monitoring during usual sodium intake.

[Disease management for heart failure patients: role of wireless technologies for telemedicine. The ICAROS project].

Healthcare costs for heart failure are increasing. The need for a better care, however, has to be matched with a policy of cost containment. A way to improve the cost-effectiveness of heart failure care is the disease management approach, in which therapy, education and follow-up are tailored for each patient by a multidisciplinary team.

Autonomic cardiac modulation in obstructive sleep apnea: effect of an oral jaw-positioning appliance.

Background: Patients with obstructive sleep apnea (OSA) are characterized by deranged cardiovascular variability, a well-established marker of cardiovascular risk. While long-term treatment with continuous positive airway pressure leads to a significant improvement of cardiovascular variability, little is known of the possibility of achieving the same results with other therapeutic approaches. The aim of our study was to investigate the responses of autonomic indexes of neural cardiac control to another type of OSA treatment based on an oral jaw-positioning appliance.

Non-invasive evaluation of coronary calcium.

With the increasing diffusion of 4-row,16-row and 64-row multislice computed tomography scanners, widespread coronary calcium scoring has become possible in Europe. This relatively easy-to-perform test has a high sensitivity and low specificity for the detection of significant coronary artery stenosis, and may have an important role in the risk stratification for future coronary artery events in selected groups of patients, such as those immediately at risk. This study reviews the techniques available for coronary calcium scoring (electron beam tomography and multislice computed tomography) with their respective protocols, as well as their advantages and disadvantages.

Intravenous contrast material administration in multislice computed tomography coronary angiography.

Rationale And Objectives: to compare contrast material (CM) administration protocols in non-invasive coronary angiography (CA) using a 16-row multislice CT (16-MSCT).

Methods: 45 patients undergoing CA with 16-MSCT were divided into three CM protocols: group 1 (140 ml@4ml/s), group 2 (140 ml = 60 ml@5ml/s + 80 ml@3ml/s), and group 3 (100 ml@4ml/s). The attenuation at the origin of the coronary vessels was assessed.

Effects of salt sensitivity on neural cardiovascular regulation in essential hypertension.

Salt-sensitive hypertensive subjects, as defined by conventional categorical classification, exhibit alterations of autonomic cardiovascular control. The aim of our study was to explore whether, in hypertensive subjects, the degree of autonomic dysfunction and the level of salt sensitivity are correlated even when the latter is only mildly elevated and displays under-threshold values. Salt sensitivity of 34 essential hypertensive subjects was assessed on a continuous basis by the salt sensitivity index after low- and high-sodium diet.

Pitfalls and feasibility of a protocol of virtual colonography designed for the screening of colo-rectal pre-cancerous lesions.

Purpose: To evaluate the pitfalls occurring during the virtual colonoscopy examination performed with a protocol designed for screening purposes.

Materials And Methods: 40 patients underwent a spiral CT for virtual colonoscopic evaluation with the following parameters: collimation 3 mm, feed 6 mm.rot(-1), pitch 2 and increment 1 mm in supine position.

Technical analysis of volume-rendering algorithms: application in low-contrast structures using liver vascularisation as a model.

Aim: To assess the influence of pre-set volume-rendering opacity curves (OC) on image quality and to identify which absolute parameters (density of aorta, hepatic parenchyma and portal vein) affect visualization of portal vascular structures (low-contrast structures).

Materials And Methods: Twenty-two patients underwent a dual-phase spiral CT with the following parameters: collimation 3 mm, pitch 2, increment 1 mm. Three scans were performed: one without contrast medium and the latter two after the injection of contrast material (conventionally identified as ''arterial'' and ''portal'').

Image assessment with multislice CT coronary angiography.

Aim: To investigate the diagnostic accuracy of two different protocols for image evaluation used in multislice computed tomography coronary angiography (MSCT-CA).

Materials And Methods: Sixty patients with suspected coronary artery disease undergoing conventional coronary angiography (CA) were enrolled for MSCT-CA. All patients underwent 16-row MSCT (Sensation 16, Siemens, Germany) with the following parameters: detector rows 16, collimation 0.

Comparison of monophasic vs biphasic administration of contrast material in non-invasive coronary angiography using a 16-row multislice Computed Tomography.

Purpose: To compare two different techniques for the administration of the bolus of contrast material (cm) in coronary angiography with multislice CT (MSCT) scanner.

Materials And Methods: Thirty consecutive patients were divided into two groups. In group 1 contrast material was administered with the monophasic protocol (140 ml of cm at 4 ml/s).

Potassium supplementation improves the natriuretic response to central volume expansion in primary aldosteronism.

Potassium depletion induced by dietary potassium restriction is known to cause sodium retention, while potassium supplementation is known to increase urinary sodium excretion. However, the ability of potassium deficiency to affect mineralocorticoid-induced sodium retention in aldosterone-producing adenoma (APA) subjects has not been extensively investigated, neither in baseline conditions nor when facilitating natriuresis through a physiological manoeuver such as central blood volume expansion. With the aim of testing the hypothesis that potassium supplementation would attenuate the mineralocorticoid-induced sodium retention, in 7 APA patients elevation of serum potassium was obtained by infusion of isosmotic potassium chloride (KCl) at a constant rate of 36 mmol/h for a 2-hour period for 5 consecutive days.

Renal and cardiovascular responses to water immersion in essential hypertension: is there a role for the opioidergic system?

Our study aimed at elucidating the effects of acute central hypervolemia induced by water immersion (WI) on renal hemodynamics, hormonal responses and on cardiovascular control in hypertensive patients, as well as at evaluating the possible role of the opioidergic system (OS) in determining these effects. Thirteen essential hypertensives were studied for 2 h before and for 2 h during WI. This was done twice, without and with i.

Plasma fatty acids response to central volume expansion in salt-sensitive hypertension.

The purpose of the present study was to investigate the possible regulation of plasma fatty acids by an acute isotonic-isooncotic central volume expansion. We measured the levels of nonesterified fatty acids (NEFA) in plasma from 12 essential hypertensive patients subjected to water immersion (WI). Central hypervolemia by WI over 2 hours caused the levels of most NEFA to increase, concomitantly with a marked natriuretic and kaliuretic response.