Chronic vagus nerve stimulation is associated with multi-year improvement in intrinsic heart rate recovery and left ventricular ejection fraction in ANTHEM-HF

Efficacy and safety of transcutaneous auricular vagus nerve stimulation for frequent premature ventricular complexes: rationale and design of the TASC-V trial

BACKGROUND

Premature Ventricular Complexes (PVCs) are very common in clinical practice, with frequent PVCs (more than 30 beats per hour) or polymorphic PVCs significantly increasing the risk of mortality. Previous studies have shown that vagus nerve stimulation improves ventricular arrhythmias. Stimulation of the auricular distribution of the vagus nerve has proven to be a simple, safe, and effective method to activate the vagus nerve. Transcutaneous au ricular vagus nerve stimulation (taVNS) has shown promise in both clinical and experimental setting for PVCs; however, high-quality clinical studies are lacking, resulting in insufficient evidence of efficacy.

METHODS

The study is a prospective, randomized, parallel-controlled trial with a 1:1 ratio between the two groups. Patients will be randomized to either the treatment group (taVNS) or the control group (Sham-taVNS) with a 6-week treatment and a subsequent 12-week follow-up period. The primary outcome is the proportion of patients with a ≥ 50% reduction in the number of PVCs monitored by 24-hour Holter. Secondary outcomes include the proportion of patients with a ≥ 75% reduction in PVCs, as well as the changes in premature ventricular beats, total heartbeats, and supraventricular premature beats recorded by 24-hour Holter. Additional assessments compared score changes in PVCs-related symptoms, as well as the score change of self-rating anxiety scale (SAS), self-rating depression scale (SDS), and 36-item short form health survey (SF-36).

DISCUSSION

The TASC-V trial will help to reveal the efficacy and safety of taVNS for frequent PVCs, offering new clinical evidence for the clinical practice.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT04415203 (Registration Date: May 30, 2020).

Vagus nerve stimulation alleviates cardiac dysfunction and inflammatory markers during heart failure in rats

Vagus nerve stimulation (VNS) is under clinical investigation as a therapy for heart failure with reduced ejection fraction (HFrEF). This study aimed to investigate its therapeutic effects on three main components of heart failure: cardiac function, cardiac remodeling and central neuroinflammation using a pressure overload (PO) rat model. Male Sprague-Dawley rats were divided into four groups: PO, PO + VNS, PO + VNS sham, and controls. All rats, except controls, underwent a PO surgery to constrict the thoracic aorta (~50 %) to induce HFrEF. Open loop VNS therapy was continuously administered to PO + VNS rats at 20 Hz, 1.0 mA for 60 days. Evaluation of cardiac function and structure via echocardiograms showed decreases in stroke volume and relative ejection fraction and increases in the internal diameter of the left ventricle during systole and diastole in PO rats (p < 0.05). However, these PO-induced adverse changes were alleviated with VNS therapy. Additionally, PO rats exhibited significant increases in myocyte cross sectional areas indicating hypertrophy, along with significant increases in myocardial fibrosis and apoptosis, all of which were reversed by VNS therapy (p < 0.05). Furthermore, VNS mitigated microglial activation in two central autonomic nuclei: the paraventricular nucleus of the hypothalamus and locus coeruleus. These findings demonstrate that when VNS therapy is initiated at an early stage of HFrEF progression (<10 % reduction in relative ejection fraction), the supplementation of vagal activity is effective in restoring multi organ homeostasis in a PO model.

The Interplay of Comorbidities in Chronic Heart Failure: Challenges and Solutions

BACKGROUND

Chronic heart failure (HF) is frequently associated with various comorbidities. These comorbid conditions, such as anemia, diabetes mellitus, renal insufficiency, and sleep apnea, can significantly impact the prognosis of patients with HF.

OBJECTIVE

This review aims to synthesize current evidence on the prevalence, impact, and management of comorbidities in patients with chronic HF.

METHODS

A comprehensive review was conducted, with a rigorous selection process. Out of an initial pool of 59,030 articles identified across various research modalities, 134 articles were chosen for inclusion. The selection spanned various research methods, from randomized controlled trials to observational studies.

RESULTS

Comorbidities are highly prevalent in patients with HF and contribute to increased hospitalization rates and mortality. Despite advances in therapies for HF with reduced ejection fraction, options for treating HF with preserved ejection fraction remain sparse. Existing treatment protocols often lack standardization, reflecting a limited understanding of the intricate relationships between HF and associated comorbidities.

CONCLUSION

There is a pressing need for a multidisciplinary, tailored approach to manage HF and its intricate comorbidities. This review underscores the importance of ongoing research efforts to devise targeted treatment strategies for HF patients with various comorbid conditions.

Application of Vagus Nerve Stimulation in Spinal Cord Injury Rehabilitation

Spinal cord injury (SCI) is a prevalent devastating condition causing significant morbidity and mortality, especially in developing countries. The pathophysiology of SCI involves ischemia, neuroinflammation, cell death, and scar formation. Due to the lack of definitive therapy for SCI, interventions mainly focus on rehabilitation to reduce deterioration and improve the patient's quality of life. Currently, rehabilitative exercises and neuromodulation methods such as functional electrical stimulation, epidural electrical stimulation, and transcutaneous electrical nerve stimulation are being tested in patients with SCI. Other spinal stimulation techniques are being developed and tested in animal models. However, often these methods require complex surgical procedures and solely focus on motor function. Vagus nerve stimulation (VNS) is currently used in patients with epilepsy, depression, and migraine and is being investigated for its application in other disorders. In animal models of SCI, VNS significantly improved locomotor function by ameliorating inflammation and improving plasticity, suggesting its use in human subjects. SCI patients also suffer from nonmotor complications, including pain, gastrointestinal dysfunction, cardiovascular disorders, and chronic conditions such as obesity and diabetes. VNS has shown promising results in alleviating these conditions in non-SCI patients, which makes it a possible therapeutic option in SCI patients.

Exploratory Investigation of the Effects of Tactile Stimulation Using Air Pressure at the Auricular Vagus Nerve on Heart Rate Variability

OBJECTIVE

To explore the effects of tactile stimulation using air pressure at the auricular branch of the vagus nerve on autonomic activity in healthy individuals.

METHODS

Three types of tactile stimulation were used in this study: continuous low-amplitude, continuous high-amplitude, and pulsed airflow. The tactile stimulations were provided to the cymba concha to investigate autonomic activity in 22 healthy participants. The mean heart rate (HR) and parameters of HR variability, including the standard deviation of R-R intervals (SDNN) and root mean square of successive R-R interval differences (RMSSD) were compared at baseline, stimulation, and recovery periods.

RESULTS

Two-way repeated measures ANOVA indicated a significant main effect of time on HR (p=0.001), SDNN (p=0.003), and RMSSD (p<0.001). These parameters showed significant differences between baseline and stimulation periods and baseline and recovery periods in the post-hoc analyses. There were no significant differences in the changes induced by stimulation type and the interaction between time and stimulation type for all parameters. One-way repeated measures ANOVA showed that HR, SDNN, and RMSSD did not differ significantly among the three time periods during sham stimulation.

CONCLUSION

Parasympathetic activity can be enhanced by auricular tactile stimulation using air pressure, targeting the cymba concha. Further studies are warranted to investigate the optimal stimulation parameters for potential clinical significance.

Noninvasive Vagus Nerve Stimulation in the Treatment of Methamphetamine Use Disorder: A Review Article

: Methamphetamine (MA) use and the mortality it causes are increasing worldwide. The neurobiological mechanisms underlying the destructive effects of MA use are complex; however, there is much evidence that MA induces the dysfunction of monoaminergic transmission and causes oxidative stress, neuroinflammation, gliosis, and apoptosis. These toxic effects are associated with cardiotoxicity and neurotoxicity and with an imbalance in the autonomic nervous system, which altogether manifest themselves in clinical symptoms, such as neuropsychiatric disorders and cardiovascular diseases. There is no approved treatment for methamphetamine use disorder (MUD) despite all efforts made to date. The behavioral and pharmacological approaches currently used for the treatment of MUD are not completely effective. In this study, it is hypothesized that the stimulation of the vagus nerve and biological pathways underlying the processes of this stimulation might be effective as adjunctive therapy. Despite the potential effects of vagus nerve stimulation (VNS) to improve MUD, no study has yet examined the clinical potential effects of VNS in patients with the disorder. Therefore, further studies, including experimental and clinical trials, are needed to examine the effects of VNS on MUD.

Optimization of respiratory-gated auricular vagus afferent nerve stimulation for the modulation of blood pressure in hypertension

Background

The objective of this pilot study was to identify frequency-dependent effects of respiratory-gated auricular vagus afferent nerve stimulation (RAVANS) on the regulation of blood pressure and heart rate variability in hypertensive subjects and examine potential differential effects by sex/gender or race.

Methods

Twenty hypertensive subjects (54.55 ± 6.23 years of age; 12 females and 8 males) were included in a within-person experimental design and underwent five stimulation sessions where they received RAVANS at different frequencies (i.e., 2 Hz, 10 Hz, 25 Hz, 100 Hz, or sham stimulation) in a randomized order. EKG and continuous blood pressure signals were collected during a 10-min baseline, 30-min stimulation, and 10-min post-stimulation periods. Generalized estimating equations (GEE) adjusted for baseline measures were used to evaluate frequency-dependent effects of RAVANS on heart rate, high frequency power, and blood pressure measures, including analyses stratified by sex and race.

Results

Administration of RAVANS at 100 Hz had significant overall effects on the reduction of heart rate (β = -2.03, p = 0.002). It was also associated with a significant reduction of diastolic (β = -1.90, p = 0.01) and mean arterial blood pressure (β = -2.23, p = 0.002) in Black hypertensive participants and heart rate in female subjects (β = -2.83, p = 0.01) during the post-stimulation period when compared to sham.

Conclusion

Respiratory-gated auricular vagus afferent nerve stimulation exhibits frequency-dependent rapid effects on the modulation of heart rate and blood pressure in hypertensive patients that may further differ by race and sex. Our findings highlight the need for the development of optimized stimulation protocols that achieve the greatest effects on the modulation of physiological and clinical outcomes in this population.

[Long-term course of heart disease: How can psychosocial care be improved?]

Cardiovascular diseases, which primarily include coronary artery disease (CAD), heart failure (HF) and cardiac arrhythmias, are the leading causes of death in the European Union and responsible for most of the serious courses of coronary disease. Acute events are usually the focus of clinical attention. In contrast, there are hardly any structured care and therapy concepts for the long-term course of these diseases. Based on a literature review, this article provides an overview of the long-term consequences and long-term care of heart diseases. Deficits in the psychosocial care of patients and possible solutions are discussed.Patients with CAD often experience problems with medication adherence and compliance to behavioural recommendations due to inadequate long-term psychosocial care. Psychological comorbidities reduce the quality of life and are a driver for health-damaging behaviour. Patients with cardiac arrhythmias often get into a vicious circle of recurrent physical complaints interacting with anxiety and panic attacks and the associated use of outpatient, emergency, or inpatient care facilities. In the course of heart failure, a clinically significant growing number of patients are treated with antidepressants, the benefit of which is rather doubtful.The apparent deficits in long-term psychosocial care of cardiovascular disease and the quality of life of patients could be improved through the increased use of systematic collaborative care models by specialised care facilities with the involvement of general practitioners.

Multifactorial Benefits of Chronic Vagus Nerve Stimulation on Autonomic Function and Cardiac Electrical Stability in Heart Failure Patients With Reduced Ejection Fraction

Heart failure with reduced left ventricular ejection fraction is a progressive disease that claims > 352,000 lives annually in the United States alone. Despite the development of an extensive array of pharmacologic and device therapies, prognosis remains poor. Disruption in autonomic balance in the form of heightened sympathetic nerve activity and reduced vagal tone have been established as major causes of heart failure progression. Interest in chronic neuromodulation mediated by vagus nerve stimulation (VNS) has intensified in recent years. This review focuses on four main goals: (1) To review the preclinical evidence that supports the concept of a cardioprotective effect of VNS on autonomic function and cardiac electrical stability along with the underlying putative mechanisms. (2) To present the initial clinical experience with chronic VNS in patients with heart failure and highlight the controversial aspects of the findings. (3) To discuss the latest findings of the multifactorial effects of VNS on autonomic tone, baroreceptor sensitivity, and cardiac electrical stability and the state-of-the-art methods employed to monitor these relationships. (4) To discuss the implications of the current findings and the gaps in knowledge that require attention in future investigations.