Impact of optimized transcutaneous auricular vagus nerve stimulation on cardiac autonomic profile in healthy subjects and heart failure patients.

To determine the optimal frequency and site of stimulation for transcutaneous vagus nerve stimulation (tVNS) to induce acute changes in the autonomic profile (heart rate (HR), heart rate variability (HRV)) in healthy subjects (HS) and patients with heart failure (HF).We designed three single-blind, randomized, cross-over studies: (1) to compare the acute effect of left tVNS at 25 Hz and 10 Hz (= 29, age 60 ± 7 years), (2) to compare the acute effect of left and right tVNS at the best frequency identified in study 1 (= 28 age 61 ± 7 years), and (3) to compare the acute effect of the identified optimal stimulation protocol with sham stimulation in HS and HF patients (= 30, age 59 ± 5 years, and= 32, age 63 ± 7 years, respectively).In study 1, left tragus stimulation at 25 Hz was more effective than stimulation at 10 Hz in decreasing HR (-1.

Nocturnal hypoxemic burden in patients with heart failure: Emerging prognostic role of its nonspecific component.

Background: Nocturnal hypoxemic burden has been shown to be a robust, independent predictor of all-cause mortality in patients with heart failure and reduced ejection fraction (HFrEF) and to occur in a severe form even in patients with low or negligible frequency of respiratory events (apneas/hypopneas). This suggests the existence of two components of hypoxemic burden: one unrelated to respiratory events and the other related. The aim of this study was to characterize these two components and to evaluate their prognostic value.

Effect of lateral position on rostral fluid shift and relationship to severity of Cheyne-Stokes respiration in heart failure patients.

Purpose: Lateral sleep position has a significant beneficial effect on the severity of Cheyne-Stokes respiration with central sleep apnea (CSR-CSA) in patients with heart failure (HF). We hypothesized that a reduction in rostral fluid shift from the legs in this position compared with the supine position may contribute to this effect.

Methods: In patients with CSR-CSA and an apnea-hypopnea index (AHI) ≥ 15/h (by standard polysomnography), uncalibrated leg fluid volume was measured in the supine, left lateral decubitus, and right lateral decubitus positions (in-laboratory assessment).

Baroreceptor Sensitivity in Individuals with CKD and Heart Failure.

Background: Heart failure is the most common cardiovascular complication of chronic kidney disease (CKD) and foreshadows a high morbidity and mortality rate. Baroreflex impairment likely contributes to cardiovascular mortality. We aimed to study the associations between CKD, heart failure, and baroreflex sensitivity (BRS) and their association with cardiovascular outcomes.

Effect of Algorithmic Music Listening on Cardiac Autonomic Nervous System Activity: An Exploratory, Randomized Crossover Study.

It is proven that music listening can have a therapeutic impact in many clinical fields. However, to assume a curative value, musical stimuli should have a therapeutic logic. This study aimed at assessing short-term effects of algorithmic music on cardiac autonomic nervous system activity.

Computer-Assisted Assessment of the Interaction Between Arousals, Breath-by-Breath Ventilation, and Chemical Drive During Cheyne-Stokes Respiration in Heart Failure Patients.

Transient increases in ventilation induced by arousal from sleep during Cheyne-Stokes respiration in heart failure patients are thought to contribute to sustaining and exacerbating the ventilatory oscillation. The only possibility to investigate the validity of this notion is to use observational data. This entails some significant challenges: (i) accurate identification of both arousal onset and offset; (ii) detection of short arousals (<3 s); (iii) breath-by-breath analysis of the interaction between arousals and ventilation; (iv) careful control for important confounding factors.

Interaction Between Arousals and Ventilation During Cheyne-Stokes Respiration in Heart Failure Patients: Insights From Breath-by-Breath Analysis.

Arousals from sleep during the hyperpneic phases of Cheyne-Stokes respiration with central sleep apnea (CSR-CSA) in patients with heart failure are thought to cause ventilatory overshoot and a consequent longer apnea, thereby sustaining and exacerbating ventilatory instability. However, data supporting this model are lacking. We investigated the relationship between arousals, hyperpnea and post-hyperpnea apnea length during CSR-CSA.

Determinants of Sleepiness at Wheel and Missing Accidents in Patients With Obstructive Sleep Apnea.

Study Objectives: Motor-vehicle crashes are frequent in untreated OSA patients but there is still uncertainty on prevalence as well as physiological or clinical determinants of sleepiness at the wheel (SW) in OSA patients. We assessed determinants of SW or sleepiness related near-miss car accident (NMA) in a group of non-professional drivers with OSA.

Methods: A 237 consecutive, treatment-naïve PSG-diagnosed OSA patients (161 males, 53.

Lack of association between heart period variability asymmetry and respiratory sinus arrhythmia in healthy and chronic heart failure individuals.

Temporal asymmetry is a peculiar aspect of heart period (HP) variability (HPV). HPV asymmetry (HPVA) is reduced with aging and pathology, but its origin is not fully elucidated. Given the impact of respiration on HPV resulting in the respiratory sinus arrhythmia (RSA) and the asymmetric shape of the respiratory pattern, a possible link between HPVA and RSA might be expected.

CARDIAC chronotropic effects of sleep-disordered breathing in patients with heart failure.

It is still not known whether the oscillation in heart rate (HR) induced by sleep-disordered breathing (SDB) in patients with heart failure entails significant chronotropic effects. We hypothesised that since cyclical changes in ventilation and arterial blood gases during SDB affect HR through multiple and complexly interacting mechanisms characterised by large inter-subject variability, chronotropic effects may change from patient to patient. A total of 42 patients with moderate-to-severe chronic heart failure with systolic dysfunction underwent an in-hospital sleep study.

Upper Limb Interactive Weightless Technology-Aided Intervention and Assessment Picks Out Motor Skills Improvement in Parkinson's Disease: A Pilot Study.

In Parkinson's disease, reaching movements are conditioned by motor planning and execution deficiency. Recently, rehabilitation, aided by high technological devices, was employed for Parkinson's disease. We aimed to (1) investigate the changes in the upper limb motor performances in a sample of a patient with Parkinson's disease after a weightless training, with a passive exoskeleton, in an augmented-feedback environment; (2) highlight differences by motor parameters (performance, speed, and movement accuracy) and by type of movement (simple or complex); and (3) evaluate movement improvements by UPDRS II-III.

Cardiac and Peripheral Autonomic Responses to Orthostatic Stress During Transcutaneous Vagus Nerve Stimulation in Healthy Subjects.

Previous studies showed that transcutaneous vagus nerve stimulation (tVNS) modulates the autonomic nervous system (ANS) in resting condition. However, the autonomic regulation in response to an orthostatic challenge during tVNS in healthy subjects remains unknown. We tested the hypothesis that tVNS reduces heart rate (HR) and alters the responsivity of ANS to orthostatic stress in healthy subjects.

Arterial oxygen saturation during Cheyne-Stokes respiration in heart failure patients: does measurement site matter?

Objective: Despite the fact that the ear is the site to monitor arterial oxygen saturation by pulse oximetry (SpO2) closest to carotid chemoreceptors, sleep studies almost invariably use finger probes. This study aimed to assess the timing and morphological differences between SpO2 signals at the ear and finger during Cheyne-Stokes respiration (CSR) in heart failure (HF) patients.

Methods: We studied 21 HF patients with CSR during a 40-min in-laboratory resting recording.

Paced Breathing Increases the Redundancy of Cardiorespiratory Control in Healthy Individuals and Chronic Heart Failure Patients.

Synergy and redundancy are concepts that suggest, respectively, adaptability and fault tolerance of systems with complex behavior. This study computes redundancy/synergy in bivariate systems formed by a target X and a driver Y according to the predictive information decomposition approach and partial information decomposition framework based on the minimal mutual information principle. The two approaches assess the redundancy/synergy of past of X and Y in reducing the uncertainty of the current state of X.

Exercise Training After Pulmonary Endarterectomy for Patients with Chronic Thromboembolic Pulmonary Hypertension.

Background: After undergoing a procedure of pulmonary endarterectomy (PEA), patients with chronic thromboembolic pulmonary hypertension (CTEPH) may still experience reduced exercise capacity. Data on effects of exercise training in these patients are scant.

Objectives: To evaluate the effectiveness of exercise training after PEA for CTEPH and if the presence of "residual pulmonary hypertension" may affect the outcome.

Physiological and clinical characteristics of patients with COPD admitted to an inpatient pulmonary rehabilitation program: A real-life study.

Background And Objective: Patient selection criteria and experimental interventions of randomized controlled trials may not reflect how things work in practice. The aim of this study was to describe the characteristics of chronic obstructive pulmonary disease (COPD) patients undergoing an inpatient pulmonary rehabilitation program (PRP) and the correlates of success.

Methods: Retrospective database review of 975 consecutive patients transferred from acute care hospitals after an acute exacerbation (group A: 14.

Temporal relationship between arousals and Cheyne-Stokes respiration with central sleep apnea in heart failure patients.

Objective: The interplay between arousals and respiratory events during Cheyne-Stokes respiration (CSR) with central sleep apnea (CSA) in heart failure (HF) patients is still not fully understood. We investigated the temporal relationship between arousals and CSR-CSA.

Methods: Episodes of CSR-CSA during sleep stages N1-N2 were analyzed in 22 HF patients with an apnea-hypopnea index ≥15/h, dominant CSA and central apnea index ≥5/h.

Chronic thromboembolic pulmonary hypertension: Reversal of pulmonary hypertension but not sleep disordered breathing following pulmonary endarterectomy.

Background: It has been hypothesized that pre-capillary pulmonary hypertension (PH) may trigger sleep disordered breathing (SDB). In patients with chronic thromboembolic PH (CTEPH), pulmonary endarterectomy (PEA) is potentially effective to improve PH. We assessed the pre- and post-operative prevalence of SDB in CTEPH patients submitted to PEA and the relationship between SDB and clinical, pulmonary and hemodynamic factors.

Estimation of baroreflex sensitivity by the bivariate phase rectified signal averaging method: a comparison with the phenylephrine method.

Objectives: A novel technique to assess spontaneous baroreflex sensitivity (BRS) by bivariate phase-rectified signal averaging (PRSA-BRS) has been recently proposed and its independent prognostic power demonstrated. This method, however, has never been compared with the phenyleprine test (Phe-BRS), commonly regarded as the reference method in clinical and research applications.

Approach: In 192 heart failure (HF) and 41 post-myocardial infarction (post-MI) patients we compared PRSA-BRS with Phe-BRS, assessing both association and agreement.

The reduction of central sleep apnoea severity in the left lateral position is not due to an improvement in cardiac haemodynamics in patients with chronic heart failure.

Objective: The severity of central sleep apnoea (CSA), a common comorbidity in patients with chronic heart failure (CHF) and reduced ejection fraction, markedly decreases from the supine to the lateral sleeping position, with no difference between the left and right positions. The mechanisms responsible for this beneficial effect have not yet been elucidated.

Methods: We tested the hypothesis that CSA attenuation in the left lateral position is due, at least in part, to an improvement in cardiac haemodynamics.

Different estimation methods of spontaneous baroreflex sensitivity have different predictive value in heart failure patients.

Objective: Several methods have been developed so far to estimate cardiac baroreflex sensitivity (BRS) through the analysis of spontaneous fluctuations of systolic arterial pressure (SAP) and R-R interval. Their relative performance in predicting cardiac mortality in heart failure patients is not known. The aim of this study was to compare the prognostic value of a set of representative indexes of spontaneous BRS in these patients.

Medicinal clays improve the endurance of loaded inspiratory muscles in COPD: a randomized clinical trial of nonpharmacological treatment.

Background: Inspiratory resistive breathing (IRB) challenges affect respiratory muscle endurance in healthy individuals, which is considered to be an interleukin 6 (IL-6)-dependent mechanism. Whether nonpharmacological thermal therapies promote the endurance of loaded inspiratory muscles in chronic obstructive pulmonary disease (COPD) is unclear. The objectives of this study were to compare the effects of two thermal interventions on endurance time (ET) and plasma IL-6 concentration following an IRB challenge.