Noninvasive low-level tragus stimulation attenuates inflammation and oxidative stress in acute heart failure.

PURPOSE: Acute decompensated heart failure (ADHF) is associated with inflammation, oxidative stress, and excess sympathetic drive. It is unknown whether neuromodulation would improve inflammation and oxidative stress in acute heart failure. We, therefore, performed this proof-of-concept study to evaluate the effects of neuromodulation using noninvasive low-level tragus stimulation on inflammation and oxidative stress in ADHF. METHODS: Nineteen patients with ejection fraction < 40% were randomized to neuromodulation 4 h twice daily (6-10 a.m. and 6-10 p.m.) (n = 8) or sham stimulation (n = 11) during hospital admission. All patients received standard-of-care treatment. Blood samples were collected at admission and discharge. Serum cytokines were assayed using standard immunosorbent techniques. Reactive oxygen species inducibility from cultured coronary endothelial cells exposed to patient sera was determined using a dihydrodichlorofluorescein probe test (expressed as fluorescein units). RESULTS: Compared to sham stimulation, neuromodulation was associated with a significant reduction of circulating serum interleukin-6 levels (-78% vs. -9%; p = 0.012). Similarly, neuromodulation led to a reduction of endothelial cell oxidative stress in the neuromodulation group (1363 units to 978 units, p = 0.003) compared to sham stimulation (1146 units to 1083 units, p = 0.094). No significant differences in heart rate, blood pressure, or renal function were noted between the two groups. CONCLUSION: In this proof-of-concept pilot study, in acute decompensated heart failure, neuromodulation was feasible and safe and was associated with a reduction in systemic inflammation and attenuation of coronary endothelial cellular oxidative stress. CLINICAL TRIAL REGISTRATION: NCT02898181.

The neurometabolic axis: A novel therapeutic target in heart failure.

Abnormal cardiac metabolism or cardiac metabolic remodeling is reported before the onset of heart failure with reduced ejection fraction (HFrEF) and is known to trigger and maintain the mechanical dysfunction and electrical, and structural abnormalities of the ventricle. A dysregulated cardiac autonomic tone characterized by sympathetic overdrive with blunted parasympathetic activation is another pathophysiological hallmark of HF. Emerging evidence suggests a link between autonomic nervous system activity and cardiac metabolism. Chronic ß-adrenergic activation promotes maladaptive metabolic remodeling whereas cholinergic activation attenuates the metabolic aberrations through favorable modulation of key metabolic regulatory molecules. Restoration of sympathovagal balance by neuromodulation strategies is emerging as a novel nonpharmacological treatment strategy in HF. The current review attempts to evaluate the 'neuro-metabolic axis' in HFrEF and whether neuromodulation can mitigate the adverse metabolic remodeling in HFrEF.

Protein kinase A: A potential marker of sympathovagal imbalance in heart failure.

Mitigation of cardiac autonomic dysregulation by neuromodulation technologies is emerging as a new therapeutic modality of heart failure (HF). This recent progress has necessitated the identification of a biomarker for the quantification of sympathovagal balance, the potential target of 'neuromodulation' strategies. The currently available autonomic nervous system assessment parameters do not truly reflect the sympathovagal balance of the ventricle. Protein kinase A (PKA) is an intracellular enzyme that plays a major role in the pathophysiology of functional and structural ventricular remodeling in HF. Interestingly, sympathetic and parasympathetic activations exert reciprocal influence on the activity of PKA. The current review attempts to evaluate the potential concept and feasibility of using in vitro assessment of PKA activity as a marker of sympathovagal balance in HF.

Cerebral small vessel disease pathology in COVID-19 patients: A systematic review.

Cerebral small vessel disease (CSVD) is the leading cause of vascular cognitive impairment and is associated with COVID-19. However, contributing factors that often accompany CSVD pathology in COVID-19 patients may influence the incidence of cerebrovascular complications. Thus, a mechanism linking COVID-19 and CSVD has yet to be uncovered and differentiated from age-related comorbidities (i.e., hypertension), and medical interventions during acute infection. We aimed to evaluate CSVD in acute and recovered COVID-19 patients and to differentiate COVID-19-related cerebrovascular pathology from the above-mentioned contributing factors by assessing the localization of microbleeds and ischemic lesions/infarctions in the cerebrum, cerebellum, and brainstem. A systematic search was performed in December 2022 on PubMed, Web of Science, and Embase using a pre-established search criterion related to history of, or active COVID-19 with CSVD pathology in adults. From a pool of 161 studies, 59 met eligibility criteria and were included. Microbleeds and ischemic lesions had a strong predilection for the corpus callosum and subcortical/deep white matter in COVID-19 patients, suggesting a distinct CSVD pathology. These findings have important implications for clinical practice and biomedical research as COVID-19 may independently, and through exacerbation of age-related mechanisms, contribute to increased incidence of CSVD.

The role of age-associated autonomic dysfunction in inflammation and endothelial dysfunction.

Aging of the cardiovascular regulatory function manifests as an imbalance between the sympathetic and parasympathetic (vagal) components of the autonomic nervous system (ANS). The most characteristic change is sympathetic overdrive, which is manifested by an increase in the muscle sympathetic nerve activity (MSNA) burst frequency with age. Age-related changes that occur in vagal nerve activity is less clear. The resting tonic parasympathetic activity can be estimated noninvasively by measuring the increase in heart rate occurring in response to muscarinic cholinergic receptor blockade; animal study models have shown this to diminish with age. Humoral, cellular, and neural mechanisms work together to prevent non-resolving inflammation. This review focuses on the mechanisms underlying age-related alternations in the ANS and how an imbalance in the ANS, evaluated by MSNA and heart rate variability (HRV), potentially facilitates inflammation when the homeostatic mechanisms between reflex neural circuits and the immune system are compromised, particularly the dysfunction of the cholinergic anti-inflammatory reflex. Physiologically, the efferent arm of this reflex acts via the [Formula: see text] 7 nicotinic acetylcholine receptors expressed in macrophages, monocytes, dendritic cells, T cells, and endothelial cells to curb the release of inflammatory cytokines, in which inhibition of NF­κB nuclear translocation and activation of a JAK/STAT-mediated signaling cascade in macrophages and other immune cells are implicated. This reflex is likely to become less adequate with advanced age. Consequently, a pro-inflammatory state induced by reduced vagus output with age is associated with endothelial dysfunction and may significantly contribute to the development and propagation of atherosclerosis, heart failure, and hypertension. The aim of this review is to summarize the relationship between ANS dysfunction, inflammation, and endothelial dysfunction in the context of aging. Meanwhile, this review also attempts to describe the role of HRV measures as a predictor of the level of inflammation and endothelial dysfunction in the aged population and explore the possible therapeutical effects of vagus nerve stimulation.

Meta-analysis Analyzing the Effect of Therapies on 6-Minute Walk Distance in Heart Failure With Reduced Ejection Fraction.

The 6-minute walk distance (6MWD) carries prognostic value in patients with heart failure with reduced ejection fraction (HFrEF). We performed this systematic review and meta-analysis to evaluate the effect of heart failure therapies on improvement in 6MWD. A systematic search of MEDLINE and Embase was conducted for randomized controlled trials measuring 6MWD at baseline and at follow-up in at least 50 patients with HFrEF across both arms. The primary outcome was improvement in 6MWD at follow-up. Meta-analysis was stratified in groups on the basis of medical therapy, device-based therapy, autonomic modulation, and exercise. Mean differences (MDs) with 95% confidence interval (CI) were reported across multiple studies that were included in the meta-analysis. A total of 44 studies met the inclusion criteria for systematic review; 17 of which were included for meta-analysis. Statistical analysis showed a statistically significant improvement in 6MWD in meters (m) at follow-up for device-based therapy (MD 20.01 m, 95% CI 18.71 to 21.31), autonomic modulation (MD 76.64 m, 95% CI 54.10 to 99.19), and exercise group (MD 39.52 m, 95% CI 19.68 to 59.35). Pooled analysis of medical therapy did not show statistically significant improvement in 6MWD at follow-up (MD 31.69 m, 95% CI -6.52 to 69.91). Device-based therapy (cardiac resynchronization therapy and cardiac contractility modulation), autonomic modulation, and exercise training programs are associated with improvement in 6MWD in patients with HFrEF. 6MWD is a useful test to gauge improvement in functional capacity among patients with HFrEF, especially those with severe symptomatic heart failure.

Microvascular dysfunction and neurovascular uncoupling are exacerbated in peripheral artery disease, increasing the risk of cognitive decline in older adults.

Peripheral artery disease (PAD) is a vascular pathology with high prevalence among the aging population. PAD is associated with decreased cognitive performance, but the underlying mechanisms remain obscure. Normal brain function critically depends on an adequate adjustment of cerebral blood supply to match the needs of active brain regions via neurovascular coupling (NVC). NVC responses depend on healthy microvascular endothelial function. PAD is associated with significant endothelial dysfunction in peripheral arteries, but its effect on NVC responses has not been investigated. This study was designed to test the hypothesis that NVC and peripheral microvascular endothelial function are impaired in PAD. We enrolled 11 symptomatic patients with PAD and 11 age- and sex-matched controls. Participants were evaluated for cognitive performance using the Cambridge Neuropsychological Test Automated Battery and functional near-infrared spectroscopy to assess NVC responses during the cognitive n-back task. Peripheral microvascular endothelial function was evaluated using laser speckle contrast imaging. We found that cognitive performance was compromised in patients with PAD, evidenced by reduced visual memory, short-term memory, and sustained attention. We found that NVC responses and peripheral microvascular endothelial function were significantly impaired in patients with PAD. A positive correlation was observed between microvascular endothelial function, NVC responses, and cognitive performance in the study participants. Our findings support the concept that microvascular endothelial dysfunction and neurovascular uncoupling contribute to the genesis of cognitive impairment in older PAD patients with claudication. Longitudinal studies are warranted to test whether the targeted improvement of NVC responses can prevent or delay the onset of PAD-associated cognitive decline.NEW & NOTEWORTHY Peripheral artery disease (PAD) was associated with significantly decreased cognitive performance, impaired neurovascular coupling (NVC) responses in the prefrontal cortex (PFC), left and right dorsolateral prefrontal cortices (LDLPFC and RDLPFC), and impaired peripheral microvascular endothelial function. A positive correlation between microvascular endothelial function, NVC responses, and cognitive performance may suggest that PAD-related cognitive decrement is mechanistically linked, at least in part, to generalized microvascular endothelial dysfunction and subsequent impairment of NVC responses.

Effects of Low-Level Tragus Stimulation on Endothelial Function in Heart Failure With Reduced Ejection Fraction.

BACKGROUND: Autonomic dysregulation in heart failure with reduced ejection fraction plays a major role in endothelial dysfunction. Low-level tragus stimulation (LLTS) is a novel, noninvasive method of autonomic modulation. METHODS AND RESULTS: We enrolled 50 patients with heart failure with reduced ejection fraction (left ventricular ejection fraction of ≤40%) in a randomized, double-blinded, crossover study. On day 1, patients underwent 60 minutes of LLTS with a transcutaneous stimulator (20 Hz, 200 µs pulse width) or sham (ear lobule) stimulation. Macrovascular function was assessed using flow-mediated dilatation in the brachial artery and cutaneous microcirculation with laser speckle contrast imaging in the hand and nail bed. On day 2, patients were crossed over to the other study arm and underwent sham or LLTS; vascular tests were repeated before and after stimulation. Compared with the sham, LLTS improved flow-mediated dilatation by increasing the percent change in the brachial artery diameter (from 5.0 to 7.5, LLTS on day 1, P = .02; and from 4.9 to 7.1, LLTS on day 2, P = .003), compared with no significant change in the sham group (from 4.6 to 4.7, P = .84 on day 1; and from 5.6 to 5.9 on day 2, P = .65). Cutaneous microcirculation in the hand showed no improvement and perfusion of the nail bed showed a trend toward improvement. CONCLUSIONS: Our study demonstrated the beneficial effects of acute neuromodulation on macrovascular function. Larger studies to validate these findings and understand mechanistic links are warranted.

Utilization of guideline-directed medical therapy in patients with de novo heart failure with reduced ejection fraction: A Veterans Affairs study.

BACKGROUND: The utilization of guideline-directed medical therapy (GDMT) significantly reduces morbidity and mortality in patients with heart failure with reduced ejection fraction (HFrEF). Previous studies have documented the underutilization of GDMT in HFrEF. The present study aimed to determine reasons for underutilization and achievement of target doses of GDMT in patients with de novo diagnosis of HFrEF. METHODS: Patients presenting with de novo HFrEF at the Veterans Affairs Medical Center were included. Baseline demographic, clinical, and echocardiographic data were collected. The utilization of target doses of GDMT was assessed at the time of discharge and 1-, 3-, 6-, and 12-month follow-up. RESULTS: Of the 95 patients who met the criteria for de novo HFrEF, 48 were included in the final analysis. Dose titration of either beta-blocker or angiotensin converting enzyme inhibitors/angiotensin receptor blockers (ACEi/ARB) was attempted in 20 patients (42%) at 1 month, 21 patients (44%) at 3 months, 13 patients (27%) at 6 months, and 14 patients (29%) at 12 months. Nine (19%) patients were on a target dose of beta-blockers and three (6%) patients were on a target dose of an ACEi/ARB at 12 months. The most common reasons for underutilization were patient-level factors, such as hypotension, acute kidney injury/hyperkalemia, and patient noncompliance. CONCLUSIONS: Utilization and achievement of target doses of GDMT were suboptimal among patients discharged with de novo HFrEF during a 1-year follow-up. Although patient factors may limit the up-titration of therapies, concerted efforts are needed to support primary care physicians in improving adherence to target doses of GDMT in patients with HFrEF.

Non-invasive Low-level Tragus Stimulation in Cardiovascular Diseases.

Low-level tragus stimulation (LLTS) is a non-invasive approach of transcutaneous vagus nerve stimulation. LLTS has applications in diseases of multiple systems, including epilepsy, depression, headache and potentially several cardiovascular diseases. LLTS has shown promising results in suppressing AF, alleviating post-MI ventricular arrhythmias and ischaemia-reperfusion injury along with improving diastolic parameters in heart failure with preserved left ventricular ejection fraction (HFpEF). Preliminary pilot clinical studies in patients with paroxysmal AF, HFpEF, heart failure with reduced ejection fraction and acute MI have demonstrated promising results. The beneficial effects are likely secondary to favourable alteration of the sympathovagal imbalance. On-going exploratory work focused on underlying mechanisms of LLTS in cardiovascular disease states and larger scale clinical trials will shed more light on the non-invasive modulation of the neuro-immune axis.

TREAT AF (Transcutaneous Electrical Vagus Nerve Stimulation to Suppress Atrial Fibrillation): A Randomized Clinical Trial.

OBJECTIVES: This study was a sham-controlled, double-blind, randomized clinical trial to examine the effect of chronic low level tragus stimulation (LLTS) in patients with paroxysmal AF. BACKGROUND: Low-level transcutaneous electrical stimulation of the auricular branch of the vagus nerve at the tragus (LLTS) acutely suppresses atrial fibrillation (AF) in humans, but the chronic effect remains unknown. METHODS: LLTS (20 Hz, 1 mA below the discomfort threshold) was delivered using an ear clip attached to the tragus (active arm) (n = 26) or the ear lobe (sham control arm) (n = 27) for 1 h daily over 6 months. AF burden over 2-week periods was assessed by noninvasive continuous electrocardiogram monitoring at baseline, 3 months, and 6 months. Five-minute electrocardiography and serum were obtained at each visit to measure heart rate variability and inflammatory cytokines, respectively. RESULTS: Baseline characteristics were balanced between the 2 groups. Adherence to the stimulation protocol (≤4 sessions lost per month) was 75% in the active arm and 83% in the control arm (p > 0.05). At 6 months, the median AF burden was 85% lower in the active arm compared with the control arm (ratio of medians: 0.15; 95% confidence interval: 0.03 to 0.65; p = 0.011). Tumor necrosis factor-alpha was significantly decreased by 23% in the active group relative to the control group (ratio of medians: 0.77; 95% confidence interval: 0.63 to 0.94; p = 0.0093). Frequency domain indices of heart rate variability were significantly altered with active versus control stimulation (p < 0.01). No device-related side effects were observed. CONCLUSIONS: Chronic, intermittent LLTS resulted in lower AF burden than did sham control stimulation, supporting its use to treat paroxysmal AF in selected patients. (Transcutaneous Electrical Vagus Nerve Stimulation to Suppress Atrial Fibrillation [TREAT-AF]; NCT02548754).

Prognostic Value of 6-Minute Walk Distance in Patients Undergoing Percutaneous Coronary Intervention: a Veterans Affairs Prospective Study.

The 6-minute walk distance (6MWD) test is a useful prognostic tool in chronic heart failure. Its usefulness after percutaneous coronary intervention is unknown. In a prospective observational study, patients underwent a 6MWD test within 2 weeks after percutaneous coronary intervention. The primary endpoint was major adverse cardiovascular events (MACE) (death, acute coronary syndrome, and heart failure admission) at one year. Receiver operating characteristic curves and area under the curve were used to determine the 6MWD test's predictive power, and the Youden index was used to measure its effectiveness. A total of 212 patients were enrolled (98% men; mean age, 65 ± 9 yr). Major comorbidities were hypertension in 187 patients (88%), dyslipidemia in 186 (88%), and diabetes mellitus in 95 (45%). Among the 176 patients (83%) who completed the 6MWD test, the incidence of MACE at one year was 22% (acute coronary syndrome in 17%; heart failure admission in 4%; and death in 3%). The area under the curve for MACE was 0.59, and 6MWD was shorter for patients with MACE than for those without (290 vs 326 m; P=0.03). For 39 patients with previous heart failure who completed the 6MWD test, the area under the curve was 0.64 for MACE and 0.78 for heart failure admission. The 6MWD test predicted reasonably well the incidence of MACE one year after percutaneous coronary intervention. In a subgroup of patients with previous heart failure, it fared even better in predicting heart failure admission. Larger studies are needed to confirm these findings.

Age-related decline in peripheral vascular health predicts cognitive impairment.

Preclinical studies demonstrate that generalized endothelial cell dysfunction and microvascular impairment are potentially reversible causes of age-related vascular cognitive impairment and dementia (VCID). The present study was designed to test the hypothesis that severity of age-related macro- and microvascular dysfunction measured in the peripheral circulation is an independent predictor of cognitive performance in older adults. In this study, we enrolled 63 healthy individuals into young (< 45 years old) and aged (> 65 years old) groups. We used principal component analysis (PCA) to construct a comprehensive peripheral vascular health index (VHI) encompassing peripheral microvascular reactivity, arterial endothelial function, and vascular stiffness, as a marker of aging-induced generalized vascular dysfunction. Peripheral macrovascular and microvascular endothelial function were assessed using flow-mediated dilation (FMD) and laser speckle contrast imaging tests. Pulse waveform analysis was used to evaluate the augmentation index (AIx), a measure of arterial stiffness. Cognitive function was measured using a panel of CANTAB cognitive tests, and PCA was then applied to generate a cognitive impairment index (CII) for each participant. Aged subjects exhibited significantly impaired macrovascular endothelial function (FMD, 5.6 ± 0.7% vs. 8.3 ± 0.6% in young, p = 0.0061), increased arterial stiffness (AIx 29.3 ± 1.8% vs 4.5 ± 2.6% in young, p < 0.0001), and microvascular dysfunction (2.8 ± 0.2 vs 3.4 ± 0.1-fold change of perfusion in young, p = 0.032). VHI showed a significant negative correlation with age (r = - 0.54, p < 0.0001) and CII significantly correlated with age (r = 0.79, p < 0.0001). VHI significantly correlated with the CII (r = - 0.46, p = 0.0003). A decline in peripheral vascular health may reflect generalized vascular dysfunction and predict cognitive impairment in older adults.

An Unusual Case of Left Sinus of Valsalva Rupture Into Right Atrium.

A 19-year-old college athlete presented with dyspnea and was found to have left sinus of Valsalva rupture into the right atrium on a transesophageal echocardiogram that was verified on coronary angiogram and computed tomography heart scan. The patient subsequently underwent surgical resection. (Level of Difficulty: Intermediate.).

Peripartum cardiomyopathy: A systematic review of the literature.

Peripartum cardiomyopathy (PPCM) is a rare cause of heart failure. It is defined as cardiomyopathy that develops in the last month of pregnancy or within 5 months of the postpartum period without an identifiable cause. We conducted a systematic review of literature of prospective studies with a focus on echocardiographic and long-term clinical outcomes in PPCM. We searched MEDLINE and Embase up to October 1, 2017. Prospective studies (sample size ≥20) reporting all-cause mortality and follow-up duration of ≥1 year were included. Of the 956 studies identified, 7 met the inclusion criteria. A total of 445 patients with a mean age of 30 years (range, 27-32 years) were included. The mean follow-up duration was 41 months (range, 12-61 months). The majority of patients had New York Heart Association class III or IV symptoms at the time of diagnosis. Only 3 studies reported data on ethnicity where the majority of patients were non-Caucasian. Most of the patients (81%-93%) were on guideline-directed medical therapy, except 1 study (41%). Left ventricular ejection fraction at baseline ranged from 24% to 35% (mean, 28%) and at follow-up from 31% to 53% (mean, 44%). Recovery in systolic function was noted in 20% to 82% (mean, 50%) of patients. All-cause mortality ranged from 0% to 28% (mean, 16%). This systematic review summarizes the evidence to date on the clinical characteristics and outcomes of patients with PPCM. Multicenter registries with long-term follow-up will help shed further light on characteristics and outcomes of patients with this rare disease.

Pharmacotherapy of Vasospastic Angina.

Vasospastic angina is a diagnosis of exclusion that manifests with signs and symptoms, which overlap with obstructive coronary artery disease, most often ST-segment elevation myocardial infarction. The pharmacotherapy that is available to treat vasospastic angina can help ameliorate angina symptoms. However, the etiology of vasospastic angina is ill-defined, making targeted pharmacotherapy difficult. Most patients receive pharmacotherapy that includes calcium channel blockers and/or long-acting nitrates. This article reviews the efficacy and safety of the pharmacotherapy used to treat vasospastic angina. High-dose calcium channel blockers possess the most evidence, with respect to decreasing angina incidence, frequency, and duration. However, not all patients respond to calcium channel blockers. Nitrates and/or alpha1-adrenergic receptor antagonists can be used in patients who respond poorly to calcium channel blockers. Albeit, evidence for use of nitrates and alpha1-adrenergic receptor antagonists in vasospastic angina is not as robust as calcium channel blockers and can exacerbate adverse effects when added to calcium channel blocker therapy. Despite having a clear benefit in patients with obstructive coronary artery disease, the benefit of beta-adrenergic receptor antagonists, statins, and aspirin remains unclear. More data are needed to elucidate whether or not these agents are beneficial or harmful to patients being treated for vasospastic angina. Overall, the use of pharmacotherapy for the treatment of vasospastic angina should be guided by patient-specific factors, such as tolerability, adverse effects, drug-drug, and drug-disease interactions.

Non-eligibility for reperfusion therapy in patients presenting with ST-segment elevation myocardial infarction: Contemporary insights from the National Cardiovascular Data Registry (NCDR).

BACKGROUND: Reperfusion therapy is lifesaving in patients presenting with ST-segment elevation myocardial infarction (STEMI). Contemporary data describing the characteristics and outcomes of patients presenting with STEMI not receiving reperfusion therapy are lacking. METHODS: Using the ACTION Registry-GWTG database, we examined 219,726 STEMI patients (January 2007-December 2013) at 721 percutaneous coronary intervention (PCI)-capable hospitals in United States. Clinical characteristics and in-hospital outcomes were stratified by those who underwent reperfusion (n = 188,200; 86%), those who did not undergo reperfusion with a reason for ineligibility (n = 27,179; 12%), and those without reperfusion but had no reason for ineligibility (n = 4,347; 2%). RESULTS: Compared with STEMI patients receiving reperfusion therapy, the nonreperfusion groups were older, were more often female, and had higher rates of hypertension, diabetes, prior myocardial infarction, prior stroke, atrial fibrillation, and left bundle-branch block and heart failure on presentation. The major reason for reperfusion noneligibility was coronary anatomy not suitable for PCI (33%). Presence of 3-vessel coronary disease was more common in the nonreperfusion groups (with or without a documented reason) compared with reperfusion group (38% and 36% vs 26%, P < .001, respectively). In-hospital mortality was higher in patients not receiving reperfusion therapy with or without a documented reason compared with the reperfusion group (adjusted odds ratio [95% CI] 1.88 [1.78-1.99] and 1.37 [1.21-1.57], respectively). CONCLUSION: Most patients with STEMI not receiving reperfusion therapy had a documented reason. Coronary anatomy not suitable for PCI was the major contributor to ineligibility. In-hospital mortality was higher in patients not receiving reperfusion therapy.