Aldosterone and anti-aldosterone effects in cardiovascular diseases and diabetic nephropathy.

Cells in the cortical collecting duct of distal nephron have been considered for a long time as the unique cellular targets of aldosterone. However, it is now clear that other cell types in non-epithelial tissues are also potential targets for aldosterone. The functions that this hormone controls in non-epithelial tissues are still a matter of debate.

Brain death assessment using instant spectral analysis of heart rate variability.

Objective: Confirmation of brain death requires an urgent diagnosis to allow rapid vital organ removal for transplantation. Evaluation of forebrain functions is commonly performed through electroencephalogram. Nevertheless, there are, for the moment, no methods that allow for an instantaneous evaluation of brainstem functions.

Use of time frequency analysis to follow transitory modulation of the cardiac autonomic system in clinical studies.

Heart rate variability (HRV) can be assessed through a time frequency analysis, the smoothed pseudo Wigner-Ville transformation (SPWVT). Such an analysis has allowed the calculation of ICF, a frequential index, extremely sensitive to the modulation of the sympatho-vagal balance. The use of ICF has been applied in the present study to two clinical situations for which a role of this balance was probable, brain death and atrial fibrillation (AF).

Simultaneous analysis of heart rate variability and myocardial contractility during head-up tilt in patients with vasovagal syncope.

Introduction: The aim of this study was to evaluate simultaneously cardiac autonomic activity, through heart rate variability (HRV) analysis, and cardiac inotropic changes during head-up tilt (HUT) in patients with recurrent vasovagal syncope.

Methods And Results: Twelve subjects implanted with a permanent dual-chamber pacemaker for recurrent vasovagal syncope characterized by marked bradycardia were studied. The tip of the right ventricular electrode was equipped with a sensor that measured peak endocardial acceleration (PEA) as an index of myocardial contractility.

Altered baroreflex gain during voluntary breathing in chronic heart failure.

Background: We assessed the behavior of the baroreflex (BR) gain in chronic heart failure (CHF) patients using the spectral analysis method during application of a forcing stimulus, i.e. respiration.