Baroreflex sensitivity assessed with the sequence method is associated with ventricular arrhythmias in patients implanted with a defibrillator for the primary prevention of sudden cardiac death.

Background: Left ventricular ejection fraction lacks accuracy in predicting sudden cardiac death, resulting in unnecessary implantation of cardioverter defibrillators for the primary prevention of sudden cardiac death. Baroreflex sensitivity could help to stratify patients at risk of ventricular arrhythmia.

Aim: To assess the association between cardiac baroreflex sensitivity and ventricular arrhythmias in patients implanted with an implantable cardioverter defibrillator for the primary prevention of sudden cardiac death after myocardial infarction.

Increased carotid stiffness and remodelling at early stages of chronic kidney disease.

Objective: Increased carotid stiffness and remodelling is reported in patients with moderate and advanced chronic kidney disease (CKD) and is associated with cardiovascular events. Here, we tested the hypothesis that carotid artery alterations start earlier, during mild CKD.

Methods: Within the Paris Prospective Study 3, a large prospective observational survey of nonreferred people aged 50-75 who received an extensive health check-up, there were 294 participants with glomerular filtration rate (GFR) of at least 45 and less than 60 ml/min per 1.

EEG profiles during general anesthesia in children: A comparative study between sevoflurane and propofol.

Background: In this prospective study, we describe the electroencephalographic (EEG) profiles in children anesthetized with sevoflurane or propofol.

Methods: Seventy-three subjects (11 years, range 5-18) were included and randomly assigned to two groups according to the anesthetic agent. Anesthesia was performed by target-controlled infusion of propofol (group P) or by sevoflurane inhalation (group S).

Sympathetic baroreceptor regulation during hypoxic hypotension in humans: new insights.

Background: Baroreceptor activation by a continuous infusion of phenylephrine selectively abolishes the muscle sympathetic nerve activity (MSNA) response to hypoxia in humans. Baroreceptor deactivation enhances the MSNA rise during hypoxia in animals. Whether this is true in humans is unknown and was tested in the present study.

The Neural Baroreflex Pathway in Subjects With Metabolic Syndrome: A Sub-Study of the Paris Prospective Study III.

The mechanisms that link metabolic syndrome (MetS) to increased cardiovascular risk are incompletely understood. We examined whether MetS is associated with the neural baroreflex pathway (NBP) and whether any such associations are independent of blood pressure values.This study involved the cross-sectional analysis of data on 2835 subjects aged 50 to 75 years from the Paris Prospective Study 3.

Visualizing oxidative stress-induced depression of cardiac vagal baroreflex by MRI/DTI in a mouse neurogenic hypertension model.

A clinical hallmark of hypertension is impairment of the cardiac vagal baroreflex, which maintains stable blood pressure and heart rate under physiological conditions. There is also evidence that oxidative stress in the brain is associated with neurogenic hypertension. We tested the hypothesis that an augmented superoxide level in the nucleus tractus solitarii (NTS), the terminal site of baroreceptor afferents, contributes to the depression of cardiac vagal baroreflex by disrupting the connectivity between the NTS and the nucleus ambiguus (NA), the origin of the vagus nerve, during neurogenic hypertension.

Involvement of the dorsomedial hypothalamus and the nucleus tractus solitarii in chronic cardiovascular changes associated with anxiety in rats.

Anxiety disorders in humans reduce both the heart rate variability (HRV) and the sensitivity of the cardiac baroreflex (BRS). Both may contribute to sudden death. To elucidate the mechanisms underlying these alterations, male rats were subjected to social defeat sessions on four consecutive days.

Cardiovascular rhythms and cardiac baroreflex sensitivity in AT(1A) receptor gain-of-function mutant mice.

A mutant mouse expressing a gain-of-function of the AT(1A) angiotensin II receptor was engineered to study the consequences of a constitutive activation of this receptor on blood pressure (BP). Cardiovascular rhythms and spontaneous cardiac baroreflex sensitivity (BRS) were evaluated using telemetric BP recordings of five transgenic (AT(1A)MUT) and five wild (AT(1A)WT) mice. The circadian rhythms were described with the Chronos-Fit program.

Tuning of the sequence technique.

The sequence method was first described by Di Rienzo in cats and applied in different species including humans. Until now, no systematic study of spontaneous baroreflex sensitivity (BRS) has been performed by the sequence method in mice. This study aimed to characterize the best estimates of BRS using the sequence method by tuning all the possible parameters, specifically, the number of beats involved in a sequence, the minimal changes in blood-pressure (BP) ramps, and the minimal changes in pulse-interval (PI) ramps.

Tissue kallikrein deficiency and renovascular hypertension in the mouse.

The kallikrein kinin system (KKS) is involved in arterial and renal functions. It may have an antihypertensive effect in both essential and secondary forms of hypertension. The role of the KKS in the development of two-kidneys, one-clip (2K1C) hypertension, a high-renin model, was investigated in mice rendered deficient in tissue kallikrein (TK) and kinins by TK gene inactivation (TK-/-) and in their wild-type littermates (TK+/+).

Acute effects of sildenafil on flow mediated dilatation and cardiovascular autonomic nerve function in type 2 diabetic patients.

Background: Sildenafil, frequently used as on demand medication for the treatment of erectile dysfunction (ED), has been suggested to improve endothelial function but also to alter blood pressure (BP) and induce sympathetic activation. In people with type 2 diabetes mellitus (T2DM), a high-risk population, the safety profile and the effects on endothelial function of a maximal sildenafil dose (100 mg) have not been investigated and therefore constituted the aim of our study.

Methods: A double-blind, placebo-controlled, cross-over trial using a single dose of 100 mg sildenafil or placebo has been conducted in 40 subjects with T2DM without known CVD.

Tuba players reproduce a Valsalva maneuver while playing high notes.

Playing wind instruments requires expiratory efforts. Blowing low notes on a tuba means a low resistance to expiration while playing high notes requires a strenuous expiratory strain. The resulting high intrathoracic pressure may reproduce a Valsalva maneuver.

Effects of atropine on the time and frequency domain estimates of blood pressure and heart rate variability in mice.

1. Indices quantifying blood pressure (BP) and heart rate (HR) variability have been recently developed and may be used to assess the contribution of the autonomic nervous system to cardiovascular fluctuations. 2.

Applicability of recent methods used to estimate spontaneous baroreflex sensitivity to resting mice.

Short-term blood pressure (BP) variability is limited by the arterial baroreflex. Methods for measuring the spontaneous baroreflex sensitivity (BRS) aim to quantify the gain of the transfer function between BP and pulse interval (PI) or the slope of the linear relationship between parallel BP and PI changes. These frequency-domain (spectral) and time-domain (sequence) techniques were tested in conscious mice equipped with telemetric devices.

Differential effects of metaboreceptor and chemoreceptor activation on sympathetic and cardiac baroreflex control following exercise in hypoxia in human.

Muscle metaboreceptors and peripheral chemoreceptors exert differential effects on the cardiorespiratory and autonomic responses following hypoxic exercise. Whether these effects are accompanied by specific changes in sympathetic and cardiac baroreflex control is not known. Sympathetic and cardiac baroreflex functions were assessed by intravenous nitroprusside and phenylephrine boluses in 15 young male subjects.

Specific serotonin reuptake inhibition in major depressive disorder adversely affects novel markers of cardiac risk.

There exists a growing body of evidence linking depression with cardiovascular events, although the mechanisms responsible remain unknown. We investigated the role of the autonomic nervous system and inflammation in the link between coronary heart disease and major depressive disorder (MDD), and examined the cardiac risk modification following pharmacological treatment of depression. We measured cardiac baroreflex function, heart rate variability, pulse pressure and high sensitivity C-reactive protein (hsCRP), all of which have an impact on cardiac risk, pre- and post-treatment in 25 patients with MDD, with no history of coronary heart disease, and in 15 healthy subjects.

Aortic stiffness and pulse pressure amplification in Wistar-Kyoto and spontaneously hypertensive rats.

In humans, increased body weight and arterial stiffness are significantly associated, independently of blood pressure (BP) level. The finding was never investigated in rodents devoid of metabolic disorders as spontaneously hypertensive rats (SHR). Using simultaneous catheterization of proximal and distal aorta, we measured body weight, intra-arterial BP, heart rate and their variability (spectral analysis), aortic pulse wave velocity (PWV), and systolic and pulse pressure (PP) amplifications in unrestrained conscious Wistar-Kyoto (WKY) rats and SHR between 6 and 24 wk of age.

Optimal frequency ranges for extracting information on cardiovascular autonomic control from the blood pressure and pulse interval spectrograms in mice.

The analysis of blood pressure (BP) and heart rate (HR) variability by spectral methods has proven a useful tool in many animal species for the assessment of the vagal and sympathetic contributions to oscillations of BP and HR. Continuous BP measurements obtained in mice by telemetry were used to characterize the spectral bandwidths of autonomic relevance by using an approach with no a priori. The paradigm was based on the autonomic blockades obtained with conventional drugs (atropine, prazosin, atenolol).

Noninvasive investigation of autonomic activity after carotid stenting or carotid endarterectomy.

Objective: Carotid artery stenting (CAS) has been introduced as an alternative to carotid endarterectomy (CEA) for the treatment of carotid artery stenosis. Both techniques seem to be associated with postoperative hemodynamic lability. Both may induce baroreceptor dysfunction, possibly leading to transient impairment of cardiovascular autonomic activity and resulting in hemodynamic instability.

Effects of rilmenidine on 24-h rhythmicity of blood pressure and spontaneous baroreflex sensitivity in essential hypertensive subjects.

Objective: To study the effects of the centrally acting imidazoline-like compound rilmenidine on the circadian and short-term cardiovascular rhythms derived from continuous blood pressure (BP) recordings in patients with mild essential hypertension.

Methods: This was a single-center, open study. Recordings were obtained from eight subjects, using a Portapres during two 24-h hospitalizations: the first after the inclusion visit and the second 4 weeks after starting rilmenidine treatment (1 or 2 mg/day).

Short-term blood pressure and heart rate variability in congenital central hypoventilation syndrome (Ondine's curse).

The effect of CCHS (congenital central hypoventilation syndrome, or Ondine's curse) on short-term BP (blood pressure) and HR (heart rate) variability was evaluated in 16-year-old subjects presenting a form of CCHS requiring night ventilatory assistance. The 12 patients were compared with 12 age- and gender-matched healthy volunteers. Recordings were obtained during daytime while the subjects were breathing spontaneously.

Does halothane really preserve cardiac baroreflex better than sevoflurane? A noninvasive study of spontaneous baroreflex in children anesthetized with sevoflurane versus halothane.

Heart rate profiles during the induction of anesthesia differ markedly between the administration of sevoflurane and halothane. Previous investigations have shown that halothane preserves cardiac parasympathetic activity more than sevoflurane. Because vagal drive to the sinus node is the main effector of arterial baroreflex control of heart rate, halothane may preserve cardiac baroreflex better than sevoflurane.