1,720,985 research outputs found
Central apnoeas, sympathetic activation and mortality in heart failure: look before you leap
No full textUse of hypocapnia for improved risk stratification in pulmonary arterial hypertension: should we return to respiratory pathophysiology?
No full textMultimodale Diagnostik der Atemmuskelkraft im Menschen und Pathophysiologie des hyperkapnischen Atemversagens bei Patienten mit neuromuskulärer Erkrankung
No full textSacubitril–valsartan treatment is associated with decrease in central apneas in patients with heart failure with reduced ejection fraction
No full textBackground: To assess the impact of sacubitril-valsartan on apneic burden in patients with heart failure with reduced ejection fraction (HFrEF), 51 stable HFrEF patients planned for switching from an ACE-i/ARB to sacubitril-valsartan were prospectively enrolled. Methods and results: At baseline and after 6 months of treatment, all patients underwent echocardiography, 24-h cardiorespiratory monitoring, neurohormonal evaluation, and cardiopulmonary exercise testing. At baseline 29% and 65% of patients presented with obstructive and central apneas, respectively. After 6 months, sacubitril-valsartan was associated with a decrease in NT-proBNP, improvement in LV function, functional capacity and ventilatory efficiency. After treatment, the apnea-hypopnea index (AHI) decreased across the 24-h period (p < 0.001), as well as at daytime (p < 0.001) and at nighttime (p = 0.026), proportionally to baseline severity. When subgrouping according to the type of apneas, daytime, nighttime and 24-h AHI decreased in patients with central apneas (all p < 0.01). Conversely, in patients with obstructive apneas, the effect of drug administration was neutral at nighttime, with significant decrease only in daytime events (p = 0.007), mainly driven by reduction in hypopneas. Conclusions: Sacubitril-valsartan on top of medical treatment is associated with a reduction in the apneic burden among a real-life cohort of HFrEF patients. The most marked reduction was observed for central apneas
Effective non-invasive ventilation reduces muscle sympathetic nerve activity in patients with stable hypercapnic COPD
No full textIncreased sympathetic drive is of prognostic significance in chronic obstructive pulmonary disease (COPD) but its determinants remain poorly understood. One potential mechanism may be chemoreflex-mediated adrenergic stimulation caused by sustained hypercapnia. This study determined the impact of non-invasive ventilation (NIV) on muscle sympathetic nerve activity (MSNA) in patients with stable hypercapnic COPD. Ten patients (age 70 ± 7 years, GOLD stage 3–4) receiving long-term NIV (mean inspiratory positive airway pressure 21 ± 7 cmH2O) underwent invasive MSNA measurement via the peroneal nerve during spontaneous breathing and NIV. Compared with spontaneous breathing, NIV significantly reduced hypercapnia (PaCO2 51.5 ± 6.9 vs 42.6 ± 6.1 mmHg, p < 0.0001) along with the burst rate (64.4 ± 20.9 vs 59.2 ± 19.9 bursts/min, p = 0.03) and burst incidence (81.7 ± 29.3 vs 74.1 ± 26.9 bursts/100 heartbeats, p = 0.04) of MSNA. This shows for the first time that correcting hypercapnia with NIV decreases MSNA in COPD
Validity of transit time–based blood pressure measurements in patients with and without heart failure or pulmonary arterial hypertension across different breathing maneuvers
No full textPurpose: Pulse transit time (PTT) derived by ECG and plethysmographic signal can be a promising alternative to invasive or oscillometry-based blood pressure (BP) monitoring in sleep laboratories because it does not cause arousals from sleep. Therefore, this study assessed the validity of PTT for BP monitoring under sleep laboratory-like conditions. Methods: Ten volunteers (55.8 ± 19.6 years), 12 patients with heart failure with reduced ejection fraction (HFrEF; 67.3 ± 8.6 years), and 14 patients with Nizza class I pulmonary arterial hypertension (PAH; 59.5 ± 13.4 years) performed different breathing patterns to simulate nocturnal sleep-disordered breathing (SDB). BP was measured at least every 15 min over 1 h using oscillometry (Task Force MonitorTM) and PTT (SOMNOscreenTM) devices in free breathing conditions and during SDB simulation (alternating phases of hyperventilation and apneas). Results: One hundred forty-two points of measurements were collected. No difference was found in both mean systolic BP (SBP) and diastolic BP (DBP) between oscillometric PTT-based BP measurements in the whole population and throughout the whole recording (SBP 111.3 ± 15.1 mmHg versus 110.0 ± 14.7 mmHg, p = 0.051; DBP 69.9 ± 12.2 versus 69.9 ± 14.2 mmHg, p = 0.701). Likewise, no significant difference in SBP and DBP was found between the two methods in the subgroups of healthy subjects, HFrEF patients and PAH patients, both in free breathing conditions (p > 0.05) and during SDB simulation (p > 0.05). Conclusions: When monitoring BP in healthy subjects, and in patients with HFrEF or PAH, PTT provides a BP estimation comparable with oscillometric measurement, though slightly inaccurate, both in the condition of regular and unstable breathing
Bioimpedance based determination of cardiac index does not show enough trueness for point of care use in patients with systolic heart failure
No full textCardiac output (CO) is a key parameter in diagnostics and therapy of heart failure (HF). The thermodilution method (TD) as gold standard for CO determination is an invasive procedure with corresponding risks. As an alternative, thoracic bioimpedance (TBI) has gained popularity for CO estimation as it is non-invasive. However, systolic heart failure (HF) itself might worsen its validity. The present study validated TBI against TD. In patients with and without systolic HF (LVEF ≤ 50% or > 50% and NT-pro-BNP < 125 pg/ml, respectively) right heart catheterization including TD was performed. TBI (Task Force Monitor©, CNSystems, Graz, Austria) was conducted semi-simultaneously. 14 patients with and 17 patients without systolic HF were prospectively enrolled in this study. In all participants, TBI was obtainable. Bland-Altman analysis indicated a mean bias of 0.3 L/min (limits of agreement ± 2.0 L/min, percentage error or PE 43.3%) for CO and a bias of -7.3 ml (limits of agreement ± 34 ml) for cardiac stroke volume (SV). PE was markedly higher in patients with compared to patients without systolic HF (54% vs. 35% for CO). Underlying systolic HF substantially decreases the validity of TBI for estimation of CO and SV. In patients with systolic HF, TBI clearly lacks diagnostic accuracy and cannot be recommended for point-of-care decision making. Depending on the definition of an acceptable PE, TBI may be considered sufficient when systolic HF is absent. Trial registration number: DRKS00018964 (German Clinical Trial Register, retrospectively registered
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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