A range of techniques for the assessment of autonomic tone are described. Impaired baroreflex control of heart period, measured in terms of heart rate variability or baroreflex sensitivity, is independently associated with adverse prognosis in patients with heart failure and following acute myocardial infarction. These techniques have not yet entered routine clinical practice.

In animals, electric field stimulation of carotid baroreceptors elicits a depressor response through sympathetic inhibition. We tested the hypothesis that the stimulation acutely reduces sympathetic vasomotor tone and blood pressure in patients with drug treatment–resistant arterial hypertension. Furthermore, we tested whether the stimulation impairs the physiological baroreflex regulation. We ...

BACKGROUND Atrial tachyarrhythmia is a common cause of morbidity and mortality in patients with univentricular physiology undergoing the Fontan operation. We examined cardiac autonomic nervous activity, a predictor of arrhythmia and sudden death in other cardiovascular disease, in patients late after the Fontan operation, employing heart rate variability (HRV) and baroreflex sensitivity. METH...

Cardiovascular System Identification (CSI), a novel technique for the noninvasive and quantitative characterization of short-term cardiovascular regulation, was applied to determine the effects of simulated microgravity environments on cardiovascular deconditioning in general and orthostatic intolerance in particular. Preliminary results indicate that simulated micro-gravity environments signif...

Angiotensin-converting enzyme 2 (ACE2), a new component of the brain renin-angiotensin system, has been suggested to participate in the central regulation of blood pressure (BP). To clarify the relationship between ACE2 and other brain renin-angiotensin system components, we hypothesized that central angiotensin II type 1 receptors reduce ACE2 expression/activity in hypertensive mice, thereby i...

OBJECTIVE To assess the influence of both sympathetic (plasma noradrenaline concentrations) and parasympathetic (baroreflex activation) tone on survival in patients with congestive heart failure. DESIGN Invasive study with determination of parasympathetic activity and follow up for at least 4.5 years. SUBJECTS 35 patients with sinus rhythm and mild to moderate heart failure (New York Heart ...

We aimed to investigate the interaction [with respect to the regulation of muscle sympathetic nerve activity (MSNA) and blood pressure] between the arterial baroreflex and muscle metaboreflex in humans. In 10 healthy subjects who performed a 1-min sustained handgrip exercise at 50% maximal voluntary contraction followed by forearm occlusion, arterial baroreflex control of MSNA (burst incidence ...

Decreased baroreflex sensitivity is an early sign of autonomic dysfunction in patients with type-1 diabetes mellitus. We evaluated the repeatability of a mild baroreflex sensitivity decrease in diabetics with respect to their heart rate. Finger blood pressure was continuously recorded in 14 young diabetics without clinical signs of autonomic dysfunction and in 14 age-matched controls for 42 min...

Objective: Glycemic control decreases the incidence and progression of diabetic complications, but increases the incidence of hypoglycemia. Hypoglycemia can impair hormonal and autonomic responses to subsequent hypoglycemia. Intensive glycemic control may increase mortality in individuals with type 2 diabetes at high risk for cardiovascular complications. We tested the hypothesis that prior exp...

This study analyzed baroreflex sensitivity, heart rate and systolic blood pressure variabilities during an oral 1 week administration of prednisone. This study examined the hypothesis that prednisone might change both systolic blood pressure level and baroreflex sensitivity. Twelve physically active male subjects participated to a double-blind, randomized cross-over study consisting of two 1-we...