Mechanisms of respiratory sinus arrhythmia in patients with mild heart failure

2001 ◽  
Vol 280 (1) ◽  
pp. H125-H131 ◽  
Author(s):  
Magdi El-Omar ◽  
Attila Kardos ◽  
Barbara Casadei
Keyword(s):  
Heart Failure ◽  
High Frequency ◽  
Spectral Power ◽  
Significant Proportion ◽  
Vagal Tone ◽  
Healthy Controls ◽  
Sinus Arrhythmia ◽  
Mild Heart Failure ◽  
Controlled Breathing ◽  
Average Contribution

The high-frequency (HF) component of the heart rate variability (HRV) is regarded as an index of cardiac vagal responsiveness. However, when vagal tone is decreased, nonneural mechanisms could account for a significant proportion of the HF component. To test this hypothesis, we examined the HRV spectral power in 20 patients with mild chronic heart failure (CHF) and 11 controls before and during ganglion blockade with trimethaphan camsylate (3–6 mg/min iv). A small HF component was still present during ganglion blockade, and its amplitude did not differ between CHF patients and controls. The average contribution of nonneural oscillations to the HF component was 15% (range 1–77%) in patients with CHF and 3% (range 0.7–30%) in healthy controls ( P < 0.005). During controlled breathing at 0.16 Hz, however, it decreased to 1% (range 0.2–13%) in healthy controls and 5% (range 1–44%) in CHF patients. Our results indicate that the HF component can significantly overestimate cardiac vagal responsiveness in patients with mild CHF. This bias is improved by controlled breathing, since this maneuver increases the vagal contribution to HF without affecting its nonneural component.

scholarly journals Cortical hyperarousal in NREM sleep normalizes from pre- to post- REM periods in individuals with frequent nightmares

SLEEP ◽  
2019 ◽  
Vol 43 (1) ◽  
Author(s):  
Borbála Blaskovich ◽  
Richárd Reichardt ◽  
Ferenc Gombos ◽  
Victor I Spoormaker ◽  
Péter Simor
Keyword(s):  
High Frequency ◽  
Slow Wave Sleep ◽  
Ptsd Symptom ◽  
Spectral Power ◽  
Lower Amount ◽  
State Transitions ◽  
Similar Distribution ◽  
Healthy Controls ◽  
Post Traumatic Stress ◽  
Symptom Intensity

Abstract Study Objectives Frequent nightmares have a high prevalence and constitute a risk factor for psychiatric conditions, but their pathophysiology is poorly understood. Our aim was to examine sleep architecture and electroencephalographic markers—with a specific focus on state transitions—related to sleep regulation and hyperarousal in participants with frequent nightmares (NM participants) versus healthy controls. Methods Healthy controls and NM participants spent two consecutive nights in the sleep laboratory. Second night spectral power during NREM to REM sleep (pre-REM) and REM to NREM (post-REM) transitions as well as during NREM and REM periods were evaluated for 22 NM participants compared to 22 healthy controls with a similar distribution of age, gender, and dream recall frequency. Results We found significant differences between the groups in the pre-REM to post-REM changes in low- and high-frequency domains. NM participants experienced a lower amount of slow-wave sleep and showed increased beta and gamma power during NREM and pre-REM periods. No difference was present during REM and post-REM phases. Furthermore, while increased pre-REM high-frequency power seems to be mainly driven by post-traumatic stress disorder (PTSD) symptom intensity, decreased low-frequency activity occurred regardless of PTSD symptom severity. Conclusion Our findings indicate that NM participants had increased high-frequency spectral power during NREM and pre-REM periods, as well as relatively reduced slow frequency and increased fast frequency spectral power across pre-and post-REM periods. This combination of reduced sleep-protective activity and increased hyperarousal suggests an imbalance between sleep regulatory and wake-promoting systems in NM participants.

scholarly journals Resting vagal activity in schizophrenia: Meta-analysis of heart rate variability as a potential endophenotype

2016 ◽  
Vol 208 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Annika Clamor ◽  
Tania M. Lincoln ◽  
Julian F. Thayer ◽  
Julian Koenig
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
High Frequency ◽  
Meta Analysis ◽  
Random Effect ◽  
Vagal Tone ◽  
Sensitivity Analyses ◽  
Psychotic Symptoms ◽  
Vagal Activity ◽  
Healthy Controls

BackgroundCardiac vagal tone, indexed by heart rate variability (HRV), is a proxy for the functional integrity of feedback mechanisms integrating central and peripheral physiology.AimsTo quantify differences in HRV in individuals with schizophrenia compared with healthy controls.MethodDatabases were systematically searched for studies eligible for inclusion. Random effect meta-analyses of standardised mean differences were calculated for vagal activity indicated by high-frequency HRV and the root mean square of successive R–R interval differences (RMSSD).ResultsThirty-four studies were included. Significant main effects were found for high-frequency HRV (P = 0.0008; Hedges' g =–0.98, 95% CI −1.56 to −0.41, k = 29) and RMSSD (P<0.0001; g =–0.91, 95% CI −1.19 to −0.62, k = 24), indicating lower vagal activity in individuals with schizophrenia than in healthy controls. Considerable heterogeneity was evident but effects were robust in subsequent sensitivity analyses.ConclusionsGiven the association between low HRV, threat processing, emotion regulation and executive functioning, reduced vagal tone may be an endophenotype for the development of psychotic symptoms.

Effect of β-blockade on baroreceptor and autonomic function in heart failure

1999 ◽  
Vol 96 (2) ◽  
pp. 137-146 ◽  
Author(s):  
John E. SANDERSON ◽  
Leata Y. YEUNG ◽  
Skiva CHAN ◽  
Brian TOMLINSON ◽  
Richard KAY ◽  
...  
Keyword(s):  
Heart Failure ◽  
Chronic Heart Failure ◽  
High Frequency ◽  
Vagal Tone ◽  
Dose Titration ◽  
Controlled Study ◽  
Control Group ◽  
Double Blind ◽  
Baroreceptor Function ◽  
Patients With Heart Failure

Although β-adrenoreceptor antagonists appear to be beneficial in chronic heart failure there is little information on their effects on autonomic and baroreceptor function which may have important prognostic implications. We sought to determine first whether β-adrenoreceptor blockade will improve baroreceptor function and vagal tone in chronic heart failure, and second whether there were any differences between standard therapy with metoprolol and the second-generation vasodilating β-blocker celiprolol. In this double-blind randomized placebo-controlled study 50 patients with stable chronic heart failure received either celiprolol 200 mg daily, metoprolol 50 mg twice daily or placebo for 12 weeks after a 4-week dose titration period. Thirty-five healthy normal subjects were also studied. Baroreceptor gain was assessed non-invasively by cross-spectral analysis of R–R and systolic blood pressure low- and high-frequency components (the α angle) during controlled respiration. High-frequency power was used as a measure of vagal modulation. Satisfactory recordings for analysis were obtained in 31 patients with heart failure. The results showed that at baseline baroreceptor gain (αHF) was significantly depressed in patients with heart failure compared with the normal control group (4.95±0.55 versus 11.73±1.32 ms/mmHg, P< 0.0001). After 12 weeks of treatment with metoprolol baroreceptor gain improved significantly whether measured while supine (P = 0.03) or standing (P = 0.009), and this was associated with a significant increase in R–R HF power (P = 0.008). There were no significant changes after treatment with celiprolol or placebo. We conclude that metoprolol but not celiprolol therapy restores baroreceptor gain towards normal and increases vagal tone in chronic heart failure. The ancillary properties of celiprolol do not appear to provide any advantages over metoprolol for the restoration of autonomic and baroreceptor function in heart failure.

scholarly journals P.199 Variability descriptors of cerebral blood flow velocity as predictors of vasospasm in Subarachnoid Hemorrhage: A feasibility study

2021 ◽  
Vol 48 (s3) ◽  
pp. S77-S77
Author(s):  
RA Rodriguez ◽  
C Herry ◽  
S English ◽  
T Ramsay ◽  
A Seely ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Subarachnoid Hemorrhage ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
High Frequency ◽  
Cerebral Blood Flow Velocity ◽  
Spectral Power ◽  
Healthy Controls ◽  
Frequency Power

Background: Transcranial Doppler (TCD) measurements poorly predict vasospasm in patients with aneurysmal subarachnoid hemorrhage (aSAH). Variability descriptors of mean cerebral blood flow velocity (mean-CBFV) may improve this prediction. We assessed the feasibility of generating reliable mean-CBFV variability metrics using extended TCD recordings in aSAH patients and healthy controls. We also explored whether these parameters are capable to discriminate aSAH patients from healthy controls, and between patients with and without vasospasm. Methods: Bilateral mean-CBFV, systemic blood pressure and heart rate were recorded for 40 minutes in 3 groups: aSAH patients (n=8) within the first 5 days post-ictus, age-matched healthy controls (n=8) and young healthy controls (n=8). We obtained linear [standard deviations, coefficient of variations, very-low, low and high-frequency power-spectra] and non-linear [Fractality, deterministic Chaos analyses] variability metrics. Results: All TCD recordings provided consistent variability metrics. aSAH patients showed higher correlation dimensions, increased high-frequency spectral power, and decreased very-low frequency power than healthy controls. aSAH patients who developed vasospasm (n=3) showed higher mean-CBFV and lower coefficient of variations than those without vasospasm (n=5). Conclusions: Descriptors of mean-CBFV variability may distinguish between aSAH patients with and without vasospasm. Future studies are required to evaluate the role of these variability parameters for risk stratification in aSAH.

scholarly journals Shoulder transcutaneous electric nerve stimulation decreases heart rate via potentiating vagal tone

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chun-Ming Hsieh ◽  
Wan-Chen Lin ◽  
Hsien-Yu Peng ◽  
Huang-Chung Chen ◽  
Yu-Cheng Ho ◽  
...  
Keyword(s):  
Heart Failure ◽  
Heart Rate ◽  
Nerve Stimulation ◽  
High Frequency ◽  
Vagal Tone ◽  
Transcutaneous Electric Nerve Stimulation ◽  
Frequency Spectra ◽  
Invasive Therapy ◽  
Non Invasive ◽  
Electric Nerve Stimulation

AbstractBy enhancing vagal activity, auricle transcutaneous electric nerve stimulation (TENS) is developed as a non-invasive therapy for heart failure. Nevertheless, though shoulder TENS used for treating adhesive capsulitis could affect vagal tone, its potential impact on heart functions remains unclear. In this study, electrocardiogram (ECG) and heart rate (HR) of subjects in response to sham, right-sided, or left-sided shoulder TENS (TENS-S, TENS-R, and TENS-L, respectively; 5 min) were recorded and analyzed. During the stimulation period, TENS-R constantly and TENS-L transiently decreased the HR of subjects; both TENS-R and TENS-L increased powers of the low- and high-frequency spectra. While TENS-R exhibiting no effect, TENS-L increased the ratio of low/high-frequency power spectrum indicating TENS-R decreased the HR through potentiating cardiac vagal tone. Collectively, these results suggest TENS could be an early and non-invasive therapy for heart failure patients before considering implant devices or devices are not feasible; moreover, therapists/physicians need to carefully monitor the potential adverse events during treatment for patient safety.Trial registration: The study protocol was registered in ClinicalTrials.gov (NCT03982472; 11/06/2019).

Update regarding anemia in heart failure

Medic ro ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 8-13
Author(s):  
Roxana Marcela Sânpălean ◽  
Dorina Nastasia Petra
Keyword(s):  
Heart Failure ◽  
Iron Deficiency ◽  
Multidisciplinary Team ◽  
Significant Proportion ◽  
Life Quality ◽  
Lower Number ◽  
Nutritional Deficiencies ◽  
Cardiac Morbidity ◽  
Appropriate Treatment

Heart failure (HF) is a burden for the healthcare system. The incidence will increase significantly due to the aging of po­pu­la­tion, which is associated with multiple comorbidities. Ane­mia and iron deficiency are common in patients with HF, their etiology being often multifactorial. The screening for anemia and iron deficiency is recommended as soon as pos­si­ble. There are often no targeted investigations, therefore a significant proportion of cases are underdiagnosed. The ma­nagement of patients may focus on identifying and correcting the cause. Anemia can occur due to nutritional deficiencies, infla­m­mation, renal failure, bone marrow dysfunction, neuro­hor­mo­nal activity, treatment and hemodilution. The appropriate the­ra­py for the patients with anemia and HF will contribute to the improvement of life quality. The only recommended iron product is ferric carboxymalose administered by in­tra­venous infusion. Under the appropriate treatment, the pa­tients showed an increase in effort tolerance, with an im­prove­ment in symptomatology and a lower number of hos­pi­ta­li­za­tion days. The management of these cases is handled by a multidisciplinary team consisting of a general prac­ti­tio­ner, a cardiologist and other specialists if the patient has other comorbidities. The role of the general practitioner is essential, as he can perform proper screening, prevention and management, developed by a multidisciplinary team, in order to reduce the cardiac morbidity and mortality.  

Estimation of the Safety of Intraoperative Fluid Therapy during Great Abdominal Surgery in Patients with Coronary Heart Disease

2020 ◽  
Vol 5 (5) ◽  
pp. 158-163
Author(s):  
V. I. Lysenko ◽  
◽  
E. A. Karpenko ◽  
Ya. V. Morozova
Keyword(s):  
Heart Failure ◽  
Coronary Heart Disease ◽  
Heart Disease ◽  
Fluid Therapy ◽  
Troponin I ◽  
Significant Proportion ◽  
Myocardial Damage ◽  
Enzyme Linked Immunosorbent Assay ◽  
Cardiac Complications ◽  
Fluid Regimen

The study of intraoperative fluid therapy tactics has been of great interest over the past few years, especially in people with concomitant coronary heart disease, as they make up a significant proportion of all surgical patients. The purpose of our study was to assess the risk of intraoperative myocardial damage in patients with concomitant coronary heart disease depending on the fluid regimen used based on monitoring of hemodynamic parameters, electrocardiogram and biomarkers of myocardial damage. Material and methods. The study involved 89 patients, who were divided into two groups depending on the tactics of intraoperative fluid therapy – restrictive and liberal. In order to detect cardiac complications at different stages, we assessed biomarkers of myocardial damage Troponin I, NT-proBNP by solid-phase enzyme-linked immunosorbent assay (ELISA). Results and discussion. Analysis of the obtained data showed that MINS (myocardial injury in noncardiac surgery) incidents were diagnosed in 5 patients (11.1%) in the first group and in 6 patients (13.6%) in the second. In patients of both groups there was an increase in NT-proBNP in the dynamics at all stages, and in the 2nd group, with a liberal regimen of intraoperative fluid therapy, it was more pronounced. It should be noted that the obtained values of NT-proBNP in all patients did not differ significantly from those allowed for this age group; such dynamics of NT-proBNP may indicate a relative risk of complications of liberal fluid therapy in patients with baseline heart failure. One of the important points when choosing the mode of fluid therapy in patients with high cardiac risk is the assessment of the initial volemic status and careful monitoring of water balance in the perioperative period with the desire for "zero" balance. The obtained dynamics of laboratory markers of myocardial damage indicates that in patients with a significant reduction in cardiac reserves compensated for heart failure, a restrictive fluid regimen is preferable, which is also confirmed by slight changes in the concentration of biomarkers. Conclusion. Thus, the study demonstrated the relative safety of selected fluid regimens in patients with concomitant coronary heart disease without signs of congestive heart failure

scholarly journals Direct measurement of vagal tone in rats does not show correlation to HRV

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Joseph T. Marmerstein ◽  
Grant A. McCallum ◽  
Dominique M. Durand
Keyword(s):  
Heart Failure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Neural Activity ◽  
Vagal Tone ◽  
Neural Recording ◽  
The Body ◽  
Autonomic Nerve ◽  
Vagal Activity ◽  
Recording Technology

AbstractThe vagus nerve is the largest autonomic nerve, innervating nearly every organ in the body. “Vagal tone” is a clinical measure believed to indicate overall levels of vagal activity, but is measured indirectly through the heart rate variability (HRV). Abnormal HRV has been associated with many severe conditions such as diabetes, heart failure, and hypertension. However, vagal tone has never been directly measured, leading to disagreements in its interpretation and influencing the effectiveness of vagal therapies. Using custom carbon nanotube yarn electrodes, we were able to chronically record neural activity from the left cervical vagus in both anesthetized and non-anesthetized rats. Here we show that tonic vagal activity does not correlate with common HRV metrics with or without anesthesia. Although we found that average vagal activity is increased during inspiration compared to expiration, this respiratory-linked signal was not correlated with HRV either. These results represent a clear advance in neural recording technology but also point to the need for a re-interpretation of the link between HRV and “vagal tone”.

scholarly journals Intestinal barrier dysfunction in irritable bowel syndrome: a systematic review

2021 ◽  
Vol 14 ◽  
pp. 175628482199358
Author(s):  
Nikita Hanning ◽  
Adam L. Edwinson ◽  
Hannah Ceuleers ◽  
Stephanie A. Peters ◽  
Joris G. De Man ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Systematic Review ◽  
Irritable Bowel Syndrome ◽  
Abdominal Pain ◽  
Barrier Function ◽  
Significant Proportion ◽  
Healthy Controls ◽  
Barrier Dysfunction ◽  
Irritable Bowel

Background and Aim: Irritable bowel syndrome (IBS) is a complex and heterogeneous disorder. Sensory, motor and barrier dysfunctions are the key physiological endophenotypes of IBS. Our aim is to review studies evaluating barrier dysfunction in adults and children with IBS, as well as to link those changes with IBS symptomatology and quality of life. Methods: A comprehensive and systematic review of multiple databases was performed up to March 2020 to identify studies comparing intestinal permeability in IBS patients with healthy controls. Both in vivo and in vitro studies were considered. Results: We identified 66 studies, of which 27 used intestinal probes to quantify barrier function. The prevalence of barrier dysfunction differed between PI-IBS (17–50%), IBS-D (37–62%) and IBS-C (4–25%). At a group level, permeability was increased compared with healthy controls in IBS-D (9/13 studies) and PI-IBS (4/4 studies), but only a minority of IBS-C (2/7 studies) and not in the only IBS-M study. All four studies in children with IBS demonstrated loss of barrier function. A heterogeneous set of tight junction genes were found to be altered in small and large intestines of adults with IBS, but these have not been evaluated in children. Positive associations were identified between barrier dysfunction and bowel disturbances (6/9 studies), abdominal pain (9/13 studies), overall symptom severity (1/6 studies), depression and anxiety (1/1 study) and quality of life (1/4 studies). Fecal slurry or supernatants of IBS patients were found to induce barrier disruption in animal models (5/6 studies). Conclusions: Barrier dysfunction is present in a significant proportion of adult and all pediatric IBS studies, especially in the IBS-D and PI-IBS subtype. The majority of studies indicated a positive association between loss of barrier function and symptoms such as abdominal pain and changes in the bowel function.

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