The sympathetic nervous system in heart failure physiology, pathophysiology, and clinical implications

Hypertension in Patients with Heart Failure with Reduced Ejection Fraction

Hypertension (HTN) is a well-known health problem associated with considerable morbidity and mortality and it is an important risk factor for the development of heart failure (HF). These findings support the need for optimizing the antihypertensive strategies to prevent the progression to HF. Interestingly, the progression from HTN to HF, among other things, may be a consequence of inappropriate over-activation of the renin-angiotensin-aldosterone system (RAAS), sympathetic nervous system (SNS), and the natriuretic peptide system (NPS). In the present review, we will discuss the pathophysiological aspects of the progression from HTN to HF with reduced ejection fraction (HFrEF) and we will focus on the evolution of different pharmacological therapies which are reported to be effective in reducing BP and improving HF outcomes, paying particular attention to the recent trials that have demonstrated the efficacy of the combined therapy of RAAS blockade and Neprilysin (NEP) inhibitor in lowering BP and mediating several beneficial actions within cardiovascular tissues, such as avoiding the worsening of HF.

Diabetic cardiomyopathy: a clinical entity or a cluster of molecular heart changes?

BACKGROUND

Although the increasing rate of cardiovascular mortality in patients with diabetes is thought to be due to the coronary atherosclerosis caused mainly by compounding factors such as dyslipidaemia and hypertension, it is now well documented that diabetes alone can lead to a vast array of molecular changes in the heart.

DESIGN

The aim of this article was to comprehensively review the pathophysiological and molecular changes leading to diabetic cardiomyopathy (DCM), as well as to critically analyse the literature that offers evidence in favour and against the existence of the overt clinical expression of this entity.

RESULTS

We included in the discussion studies that have revealed the existence of diabetic cardiomyopathy with unique remodelling pattern when compared to other types of cardiomyopathies. On the other hand, several studies debate the existence of clinically discernible cardiomyopathy caused only by diabetes and were also presented and discussed in details.

CONCLUSION

Clinicians should be aware of DCM when facing patients with diabetes in order both to recognize on time relevant symptoms and to intensively look for and treat other compounding factors, apart from optimal glucose control. Furthermore, the elucidation of the pathophysiological mechanisms leading to DCM could provide new therapeutic targets for heart disease, which will be wonderful for the good of our patients.

Radionuclide Imaging Applications in Cardiomyopathies and Heart Failure

Multiple epidemiological factors including population aging and improved survival after acute coronary syndromes have contributed to a heart failure (HF) prevalence in the USA in epidemic proportions. In the absence of transplantation, HF remains a progressive disease with poor prognosis. The structural and functional abnormalities of the myocardium in HF can be assessed by various radionuclide imaging techniques. Radionuclide imaging may be uniquely suited to address several important clinical questions in HF such as identifying etiology and guiding the selection of patients for coronary revascularization. Newer approaches such as autonomic innervation imaging, phase analysis for synchrony assessment, and other molecular imaging techniques continue to expand the applications of radionuclide imaging in HF. In this manuscript, we review established and evolving applications of radionuclide imaging for the diagnosis, risk stratification, and management of HF.

Reduced epicardial vagal nerve density and impaired vagal control in a rat myocardial infarction-heart failure model

BACKGROUND

Autonomic remodeling, characterized by sympathetic activation and vagal withdrawal, contributes to heart failure (HF) progression. However, the exact mechanism(s) responsible for vagal withdrawal in HF remain(s) unclear, and whether HF causes epicardial autonomic nerve remodeling is unknown.

METHODS AND RESULTS

Myocardial infarction (MI) was produced in 14 Sprague-Dawley rats, and 10 sham surgery rats served as the control. MI-HF was confirmed 2 months after the surgery by echocardiography and hemodynamic measurement. Cervical vagal nerve stimulation was delivered to examine the heart rate slowing effect. Whole heart acetylcholinesterase histochemistry was used to examine the epicardial autonomic nerve remodeling at dorsal ventricles (remote from the infarcted area). Compared with the control animals, the same vagal nerve stimulation had less heart rate slowing effect in MI-HF group. Both epicardial nerve bundle length-density (2.56±0.60 μm/mm² versus 1.68±0.46 μm/mm², P=.001) and branching point-density (1.24±0.25 points/mm² versus 0.66±0.18 points/mm², P<.001) were lower in MI-HF rats. The chemically stained epicardial nerve bundles contain both sympathetic (tyrosine hydroxylase positive) and vagal (choline acetyltransferase positive) fibers. However, within the stained nerve bundle, the chemical color corresponds mainly with the vagal fibers.

CONCLUSIONS

Whole heart acetylcholinesterase histochemistry revealed a decreased ventricular epicardial vagal nerve density in MI-HF rats, which may contribute to impaired cardiac vagal control in HF.

Renal denervation in the treatment of resistant hypertension: Dead, alive or surviving?

Hypertension is one of the most common chronic clinical problems encountered by physicians. The prevalence of resistant hypertension is estimated at 9% in the US. Patients with resistant hypertension have been shown to be at higher risk for adverse cardiovascular events, hence the need for greater efforts in improving the treatment of hypertension. The renal sympathetic nerves play an important role in the development of hypertension, mediated via sodium and water retention, increased renin release and alterations in renal blood flow. The proximity of the afferent and efferent renal sympathetic nerves to the adventitia of the renal arteries suggested the feasibility of an endovascular, selective, minimally invasive approach to renal denervation; a potential treatment option for resistant hypertension. While the RAPID, Reduce-HTN, EnligHTN, DENERHTN and Symplicity HTN-1 and -2 studies showed significant benefit of renal denervation in the treatment of resistant hypertension, the results of Oslo RDN, Prague-15 and Symplicity HTN-3 were not so favorable. Future well-designed clinical trials are needed to ascertain the benefits or otherwise of renal denervation in treatment-resistant hypertension.

Neprilysin inhibition: A brief review of past pharmacological strategies for heart failure treatment and future directions

Heart failure (HF) is a manifestation of aberrant vascular responses and remains a public health concern with a worldwide prevalence of around 23 million and a 5-year mortality numerically equivalent to many cancers. Over the last two decades, mortality from HF reached a plateau with current pharmaceutical agents and mechanical cardiac support. In the last several years, various "novel" pharmaceutical agents have been tested in clinical trials and ultimately met with disappointment, showing only incremental benefit in the treatment of HF. Designing a HF drug with enhanced efficacy over existing agents seemed like a Sisyphean task. Yet again, pharmaceutical chemists have demonstrated their prowess in lateral thinking by developing a vasoactive agent which is a co-crystallized compound of valsartan and sacubitril in a one-to-one molar ratio; the former molecule belongs to a family of agents that are the current standard of care for HF and the latter molecule is a novel agent which inhibits neprilysin - a neutral endopeptidase found in human plasma which alters neurohumoral responses. In July of 2015, a drug which is a combination of valsartan and sacubitril was formally licensed by the United States Food and Drug Administration for the treatment of HF. This review describes the evolution of HF medications focusing on rational drug design with the first HF medication, the beta-adrenergic receptor antagonist. We then discuss the biochemical and physiological properties of sacubitril/valsartan which likely lead to its dramatic ability to ameliorate HF mortality.

Acute Decompensated Heart Failure

Heart failure (HF) is a societal burden due to its high prevalence, frequent admissions for acute decompensated heart failure (ADHF), and the economic impact of direct and indirect costs associated with HF and ADHF. Common etiologies of ADHF include medication and diet noncompliance, arrhythmias, deterioration in renal function, poorly controlled hypertension, myocardial infarction, and infections. Appropriate medical management of ADHF in patients is guided by the identification of signs and symptoms of fluid overload or low cardiac output and utilization of evidence-based practices. In patients with fluid overload, various strategies for diuresis or ultrafiltration may be considered. Depending on hemodynamics and patient characteristics, vasodilator, inotropic, or vasopressor therapies may be of benefit. Upon ADHF resolution, patients should be medically optimized, have lifestyle modifications discussed and implemented, and medication concierge service considered. After discharge, a multidisciplinary HF team should follow up with the patient to ensure a safe transition of care. This review article evaluates the management options and considerations when treating a patient with ADHF.

Effect of High Thoracic Sympathetic Nerve Block on Serum Collagen Biomarkers in Patients with Chronic Heart Failure

OBJECTIVES

The impact of high thoracic sympathetic block (HTSB) on myocardial fibrosis in chronic heart failure (HF) is unclear. Myocardial collagen synthesis can be assessed by measuring circulating biomarkers. We observed the effect of HTSB on serum collagen biomarkers in HF.

METHODS

Forty-four patients were randomized to a control and a HTSB group. They received routine medications. Repeated epidural injections were given to the HTSB group for 4 weeks. Echocardiography and measurements of serum carboxy-terminal propeptide of procollagen type I (PICP) and amino-terminal propeptide of procollagen type III (PIIINP) were performed at baseline and 4 weeks later.

RESULTS

There were significant reductions in left atrial diameter, left ventricular (LV) diameter and volume, LV weight index (LVWI) and serum PICP and PIIINP levels in the HTSB group (p < 0.05). The changes in LV end-systolic volume and ejection fraction (LVEF) were greater in the HTSB group than in the control group (p < 0.05). In the HTSB group, the decreases in PICP and PIIINP were correlated with the decrease in LVWI (PICP: r = 0.695, p = 0.000; PIIINP: r = 0.642, p = 0.001), and the decrease in PICP was negatively associated with the rise in LVEF (r = -0.813, p = 0.000).

CONCLUSION

HTSB reduces myocardial fibrosis in HF, which may accompany the improvement of LV hypertrophy and dysfunction.

Effects of renal sympathetic denervation on cardiac systolic function after myocardial infarction in rats

This study investigated the therapeutic effects of renal denervation on cardiac systolic function after myocardial infarction (MI) in rats and the mechanism involved. Fifty male SD rats were randomly assigned to the sham group (n = 15), the MI group (n = 20), and the MI plus renal denervation group (n = 15). MI was established through thoracotomic ligation of the anterior descending artery. Renal denervation was achieved by laparotomic stripping of the renal arterial adventitial sympathetic nerve, approximately 3 mm from the abdominal aorta. Left ventricular function and hemodynamics were measured several weeks following MI. The left ventricular systolic function of the MI group was significantly reduced and the systolic blood pressure (SBP) remarkably declined. In rats with MI treated with renal denervation, the left ventricular ejection fraction (EF), fractional shortening (FS) and SBP markedly improved compared with the MI group. However, heart rate and fibrosis decreased significantly. These findings suggest that renal denervation has therapeutic effects on post-MI cardiac dysfunction. These effects are associated with increased left ventricular ejection fraction (LVEF) and SBP, as well as reduced heart rate and fibrosis. This may represent a new approach to the treatment of post-MI remodeling and subsequent heart failure.

Regulation of sarcoplasmic reticulum Ca2+ release by serine-threonine phosphatases in the heart

The amount and timing of Ca²⁺ release from the sarcoplasmic reticulum (SR) during cardiac cycle are the main determinants of cardiac contractility. Reversible phosphorylation of the SR Ca²⁺ release channel, ryanodine receptor type 2 (RyR2) is the central mechanism of regulation of Ca²⁺ release in cardiomyocytes. Three major serine-threonine phosphatases including PP1, PP2A and PP2B (calcineurin) have been implicated in modulation of RyR2 function. Changes in expression levels of these phosphatases, their activity and targeting to the RyR2 macromolecular complex were demonstrated in many animal models of cardiac disease and humans and are implicated in cardiac arrhythmia and heart failure. Here we review evidence in support of regulation of RyR2-mediated SR Ca²⁺ release by serine-threonine phosphatases and the role and mechanisms of dysregulation of phosphatases in various disease states.

Exercise training-induced modification in autonomic nervous system: An update for cardiac patients

Patients with cardiovascular disease show autonomic dysfunction, including sympathetic activation and vagal withdrawal, which leads to fatal events. This review aims to place sympathovagal balance as an essential element to be considered in management for cardiovascular disease patients who benefit from a cardiac rehabilitation program. Many studies showed that exercise training, as non-pharmacologic treatment, plays an important role in enhancing sympathovagal balance and could normalize levels of markers of sympathetic flow measured by microneurography, heart rate variability or plasma catecholamine levels. This alteration positively affects prognosis with cardiovascular disease. In general, cardiac rehabilitation programs include moderate-intensity and continuous aerobic exercise. Other forms of activities such as high-intensity interval training, breathing exercises, relaxation and transcutaneous electrical stimulation can improve sympathovagal balance and should be implemented in cardiac rehabilitation programs. Currently, the exercise training programs in cardiac rehabilitation are individualized to optimize health outcomes. The sports science concept of the heart rate variability (HRV)-vagal index used to manage exercise sessions (for a goal of performance) could be implemented in cardiac rehabilitation to improve cardiovascular fitness and autonomic nervous system function.

Non-neuronal cardiac cholinergic system influences CNS via the vagus nerve to acquire a stress-refractory propensity

We previously developed cardiac ventricle-specific choline acetyltransferase (ChAT) gene-overexpressing transgenic mice (ChAT tgm), i.e. an in vivo model of the cardiac non-neuronal acetylcholine (NNA) system or non-neuronal cardiac cholinergic system (NNCCS). By using this murine model, we determined that this system was responsible for characteristics of resistance to ischaemia, or hypoxia, via the modulation of cellular energy metabolism and angiogenesis. In line with our previous study, neuronal ChAT-immunoreactivity in the ChAT tgm brains was not altered from that in the wild-type (WT) mice brains; in contrast, the ChAT tgm hearts were the organs with the highest expression of the ChAT transgene. ChAT tgm showed specific traits in a central nervous system (CNS) phenotype, including decreased response to restraint stress, less depressive-like and anxiety-like behaviours and anti-convulsive effects, all of which may benefit the heart. These phenotypes, induced by the activation of cardiac NNCCS, were dependent on the vagus nerve, because vagus nerve stimulation (VS) in WT mice also evoked phenotypes similar to those of ChAT tgm, which display higher vagus nerve discharge frequency; in contrast, lateral vagotomy attenuated these traits in ChAT tgm to levels observed in WT mice. Furthermore, ChAT tgm induced several biomarkers of VS responsible for anti-convulsive and anti-depressive-like effects. These results suggest that the augmentation of the NNCCS transduces an effective and beneficial signal to the afferent pathway, which mimics VS. Therefore, the present study supports our hypothesis that activation of the NNCCS modifies CNS to a more stress-resistant state through vagus nerve activity.

Effects of varenicline on sympatho-vagal balance and cue reactivity during smoking withdrawal: a randomised placebo-controlled trial

Background

Varenicline is an effective smoking cessation medication. Some concern has been raised that its use may precipitate adverse cardiovascular events although no patho-physiological mechanism potentially underlying such an effect has been reported. The aim of this study was to test the hypothesis that varenicline impacts on sympatho-vagal balance during smoking withdrawal.

Methods

In this randomised, placebo-controlled trial, muscle sympathetic nerve activity (MSNA), baroreflex sensitivity (BRS), heart rate, and blood pressure were assessed in 17 smokers four weeks before a quit attempt (baseline) and again on the third day of that quit attempt (acute smoking withdrawal).

Results

Regarding the primary endpoint of our study, we did not find a significant effect of varenicline compared to placebo on changes in MSNA burst incidence between baseline and acute smoking withdrawal (−3.0 ± 3.3 vs.−3.9 ± 5.0 bursts/100 heart beats; p = 0.308). However, heart rate and systolic blood pressure significantly decreased in the placebo group only, while no significant changes in these parameters were observed in the varenicline group. Exposure to smoking cues during acute withdrawal lead to a significant increase of heart rate in the placebo group, while heart rate decreased in the varenicline group, and the difference in these changes was significant between groups (+2.7 ± 1.0 vs.−1.8 ± 0.5 1/min; p = 0.002). In all 17 participants combined, a significant increase in heart rate during smoking cue exposure was detected in subjects who relapsed in the course of six weeks after the quit date compared to those who stayed abstinent (+2.5 ± 1.2 vs.−1.1 ± 0.7; p = 0.018). Six-week abstinence rates were higher in the varenicline group compared to placebo (88 vs. 22 % p = 0.015).

Conclusion

We did not find evidence of adverse effects of varenicline on sympatho-vagal balance. Varenicline probably blunts the heart rate response to smoking cues, which may be linked to improved cessation outcome.

Calcific Aortic Valve Disease: Part 2-Morphomechanical Abnormalities, Gene Reexpression, and Gender Effects on Ventricular Hypertrophy and Its Reversibility

In part 1, we considered cytomolecular mechanisms underlying calcific aortic valve disease (CAVD), hemodynamics, and adaptive feedbacks controlling pathological left ventricular hypertrophy provoked by ensuing aortic valvular stenosis (AVS). In part 2, we survey diverse signal transduction pathways that precede cellular/molecular mechanisms controlling hypertrophic gene expression by activation of specific transcription factors that induce sarcomere replication in-parallel. Such signaling pathways represent potential targets for therapeutic intervention and prevention of decompensation/failure. Hypertrophy provoking signals, in the form of dynamic stresses and ligand/effector molecules that bind to specific receptors to initiate the hypertrophy, are transcribed across the sarcolemma by several second messengers. They comprise intricate feedback mechanisms involving gene network cascades, specific signaling molecules encompassing G protein-coupled receptors and mechanotransducers, and myocardial stresses. Future multidisciplinary studies will characterize the adaptive/maladaptive nature of the AVS-induced hypertrophy, its gender- and individual patient-dependent peculiarities, and its response to surgical/medical interventions. They will herald more effective, precision medicine treatments.

New medications for heart failure

Heart failure is common and results in substantial morbidity and mortality. Current guideline-based therapies for heart failure with reduced ejection fraction, including beta blockers, angiotensin converting enzyme (ACE) inhibitors, and aldosterone antagonists aim to interrupt deleterious neurohormonal pathways and have shown significant success in reducing morbidity and mortality associated with heart failure. Continued efforts to further improve outcomes in patients with heart failure with reduced ejection fraction have led to the first new-in-class medications approved for heart failure since 2005, ivabradine and sacubitril/valsartan. Ivabradine targets the If channels in the sinoatrial node of the heart, decreasing heart rate. Sacubitril/valsartan combines a neprilysin inhibitor that increases levels of beneficial vasodilatory peptides with an angiotensin receptor antagonist. On a background of previously approved, guideline-directed medical therapies for heart failure, these medications have shown improved clinical outcomes ranging from decreased hospitalizations in a select group of patients to a reduction in all-cause mortality across all pre-specified subgroups. In this review, we will discuss the previously established guideline-directed medical therapies for heart failure with reduced ejection fraction, the translational research that led to the development of these new therapies, and the results from the major clinical trials of ivabradine and sacubitril/valsartan.

Bisoprolol in idiopathic pulmonary arterial hypertension: an explorative study

While beta-blockers are considered contraindicated in pulmonary arterial hypertension (PAH), the prognostic significance of sympathetic nervous system over-activity suggests a potential benefit of beta-blocker therapy. The aim of this randomised, placebo-controlled, crossover, single centre study was to determine the effects of bisoprolol on right ventricular ejection fraction (RVEF) in idiopathic PAH (iPAH) patients. Additional efficacy and safety parameters were explored.Patients with optimally treated, stable iPAH (New York Heart Association functional class II/III) were randomised to placebo or bisoprolol. Imaging and functional measurements were performed at baseline, crossover and end of study.18 iPAH patients were included, because inclusion faltered before enrolment of the targeted 25 patients. 17 patients completed 6 months of bisoprolol, 15 tolerated bisoprolol, one patient required intravenous diuretics. Bisoprolol was associated with a lower heart rate (17 beats per minute, p=0.0001) but RVEF remained unchanged. A drop in cardiac index (0.5 L·min(-1)·m(-2), p=0.015) was observed, along with a trend towards a decreased 6-min walking distance (6MWD).Although careful up-titration of bisoprolol was tolerated by most patients and resulted in a decreased heart rate, no benefit of bisoprolol in iPAH was demonstrated. Decreases in cardiac index and 6MWD suggest a deteriorated cardiac function. The results do not favour the use of bisoprolol in iPAH patients.

The strange case of the ear and the heart: The auricular vagus nerve and its influence on cardiac control

The human ear seems an unlikely candidate for therapies aimed at improving cardiac function, but the ear and the heart share a common connection: the vagus nerve. In recent years there has been increasing interest in the auricular branch of the vagus nerve (ABVN), a unique cutaneous subdivision of the vagus distributed to the external ear. Non-invasive electrical stimulation of this nerve through the skin may offer a simple, cost-effective alternative to the established method of vagus nerve stimulation (VNS), which requires a surgical procedure and has generated mixed results in a number of clinical trials for heart failure. This review discusses the available evidence in support of modulating cardiac activity using this strange auricular nerve.

Impacts of Surgically Performed Renal Denervation on the Cardiovascular and Electrophysiological Variables in the Chronic Atrioventricular Block Dogs - Comparison With Those of Amiodarone Treatment

BACKGROUND

In order to begin to precisely clarify the impact of renal denervation on the blood pressure, atrial fibrillation and ventricular tachyarrhythmias, in addition to proarrhythmic potential, its cardiovascular effects were assessed by using the chronic complete atrioventricular block dogs.

METHODS AND RESULTS

Cardiohemodynamic and electrophysiological effects, together with neurohumoral factors and/or electrolytes, were assessed before and 4 weeks after either renal denervation (n=5) or amiodarone treatment (n=6). Amiodarone hydrochloride was given orally to the animals every day in a dose of 200 mg/day for the first 7 days followed by 100 mg/day for the following 21 days. The renal denervation decreased the systolic pressure, idioventricular rate, prolonged ventricular effective refractory period, and slightly suppressed the adrenergic tone and the renin-angiotensin-aldosterone system, but hardly affected the atrial effective refractory period and terminal repolarization period. Amiodarone prolonged the atrial effective refractory period, whereas no significant change was detected in the other variables.

CONCLUSIONS

Surgically performed renal denervation may possess the anti-ventricular tachyarrhythmic rather than anti-atrial fibrillatory potentials, and it also modestly decreased the blood pressure. Thus, currently obtained information may be used as guidance for better understanding the utility and limitation of renal denervation against various types of cardiovascular diseases. (Circ J 2016; 80: 1556-1563).

Worry is associated with robust reductions in heart rate variability: a transdiagnostic study of anxiety psychopathology

BACKGROUND

Individuals with anxiety disorders display reduced resting-state heart rate variability (HRV), although findings have been contradictory and the role of specific symptoms has been less clear. It is possible that HRV reductions may transcend diagnostic categories, consistent with dimensional-trait models of psychopathology. Here we investigated whether anxiety disorders or symptoms of anxiety, stress, worry and depression are more strongly associated with resting-state HRV.

METHODS

Resting-state HRV was calculated in participants with clinical anxiety (n = 25) and healthy controls (n = 58). Symptom severity measures of worry, anxiety, stress, and depression were also collected from participants, regardless of diagnosis.

RESULTS

Participants who fulfilled DSM-IV criteria for an anxiety disorder displayed diminished HRV, a difference at trend level significance (p = .1, Hedges' g = -.37, BF10 = .84). High worriers (Total n = 41; n = 22 diagnosed with an anxiety disorder and n = 19 not meeting criteria for any psychopathology) displayed a robust reduction in resting state HRV relative to low worriers (p = .001, Hedges' g = -.75, BF10 = 28.16).

CONCLUSIONS

The specific symptom of worry - not the diagnosis of an anxiety disorder - was associated with the most robust reductions in HRV, indicating that HRV may provide a transdiagnostic biomarker of worry. These results enhance understanding of the relationship between the cardiac autonomic nervous system and anxiety psychopathology, providing support for dimensional-trait models consistent with the Research Domain Criteria framework.

Looking for agonists of β2 adrenergic receptor from Fuzi and Chuanwu by virtual screening and dual-luciferase reporter assay

More and more studies demonstrated that β2 adrenergic receptor (β2-AR) plays a crucial role for the treatment of heart failure. Chuanwu and Fuzi have been used over thousands of years in China for the treatment of heart failure. Considering the effects of these herbs are very similar to β2-AR agonists, we presume whether β2-AR agonists can be found from Fuzi and Chuanwu. Fuzi and Chuanwu decoction were used to receive the luciferase reporter activity assay to verify the hypothesis, and the result is positive and encouraging. For it is very difficult to get all of the monomer compounds of Fuzi and Chuanwu, virtual screening was used to find potential β2-AR agonists and a cell-based β2-AR agonist functional evaluation model, combined with a luciferase reporter assay system, was used to confirm the final result. In this research, 45 compounds were identified as β2-AR agonists, and four compounds were verified and the rest need further experiment.

Procalcitonin and Midregional Proatrial Natriuretic Peptide as Markers of Ischemic Stroke: The Northern Manhattan Study

BACKGROUND AND PURPOSE

Chronic infections and neuroendocrine dysfunction may be risk factors for ischemic stroke (IS). We hypothesized that selected blood biomarkers of infection (procalcitonin [PCT]), hypothalamic-pituitary-axis function (copeptin), and hemodynamic dysfunction (midregional proatrial natriuretic peptide [MRproANP]) are associated with incident IS risk in the multiethnic, urban Northern Manhattan Study (NOMAS) cohort.

METHODS

A nested case-control study was performed among initially stroke-free participants. Cases were defined as first IS (n=172). We randomly selected controls among those who did not develop an event (n=344). We calculated Cox proportional hazards models with inverse probability weighting to estimate the association of blood biomarkers with risk of stroke after adjusting for demographic, behavioral, and medical risk factors.

RESULTS

Those with PCT and MRproANP, but not copeptin, in the top quartile, compared with the lowest quartile, were associated with IS (for PCT adjusted hazard ratio [HR], 1.9; 95% confidence interval [CI], 1.0-3.8 and for MRproANP adjusted HR, 3.5; 95% CI, 1.6-7.5). The associations of PCT and MRproANP differed by stroke etiology; PCT levels in the top quartile were particularly associated with small vessel stroke (adjusted HR, 5.1; 95% CI, 1.4-18.7) and MRproANP levels with cardioembolic stroke (adjusted HR, 16.3; 95% CI, 3.7-70.9).

CONCLUSIONS

Higher levels of PCT, a marker of infection, and MRproANP, a marker for hemodynamic stress, were independently associated with IS risk. PCT was specifically associated with small vessel and MRproANP with cardioembolic stroke risk. Further study is needed to validate these biomarkers and determine their significance in stroke risk prediction and prevention.

Low-Level Vagus Nerve Stimulation Reverses Cardiac Dysfunction and Subcellular Calcium Handling in Rats With Post-Myocardial Infarction Heart Failure

Vagus nerve stimulation (VNS), targeting the imbalanced autonomic nervous system, is a promising therapeutic approach for chronic heart failure (HF). Moreover, calcium cycling is an important part of cardiac excitation-contraction coupling (ECC), which also participates in the antiarrhythmic effects of VNS. We hypothesized that low-level VNS (LL-VNS) could improve cardiac function by regulation of intracellular calcium handling properties. The experimental HF model was established by ligation of the left anterior descending coronary artery (LAD). Thirty-two male Sprague-Dawley rats were divided into 3 groups as follows; control group (sham operated without coronary ligation, n = 10), HF-VNS group (HF rats with VNS, n = 12), and HF-SS group (HF rats with sham nerve stimulation, n = 10). After 8 weeks of treatment, LL-VNS significantly improved left ventricular ejection fraction (LVEF) and attenuated myocardial interstitial fibrosis in the HF-VNS group compared with the HF-SS group. Elevated plasma norepinephrine and dopamine, but not epinephrine, were partially reduced by LL-VNS. Additionally, LL-VNS restored the protein and mRNA levels of sarcoplasmic reticulum Ca(2+) ATPase (SERCA2a), Na(+)-Ca(2+) exchanger 1 (NCX1), and phospholamban (PLB) whereas the expression of ryanodine receptor 2 (RyR2) as well as mRNA level was unaffected. Thus, our study results suggest that the improvement of cardiac performance by LL-VNS is accompanied by the reversal of dysfunctional calcium handling properties including SERCA2a, NCX1, and PLB which may be a potential molecular mechanism of VNS for HF.

Preliminary effects of renal denervation with saline irrigated catheter on cardiac systolic function in patients with heart failure: A Prospective, Randomized, Controlled, Pilot Study

OBJECTIVE

To assess efficacy and safety of renal denervation (RDN) for heart failure (HF).

BACKGROUND

RDN has been demonstrated to be an effective method in lowing overactive sympathetic nerve. However, it's feasibility and efficacy for HF is unclear.

METHODS

In this randomized, controlled pilot study, patients with HF were randomly assigned in 1:1 ratio to undergo RDN plus optimal medical therapy (RDN group) or only optimal medical therapy (control group). Before randomization, patients received optimal medical therapy at least half a year. Primary efficacy end point was the change in LVEF over six months; secondary efficacy end points were the change in six-minute walk distance and SF-36 Health Survey scores over six months.

RESULTS

Up to Apr 2015, sixty symptomatic HF patients were successfully enrolled into study. Thirty patients were randomly assigned to RDN group and 30 patients were randomly assigned to control group. All patients completed six months follow up. During follow up, no severe adverse events were observed. Blood pressure was stable in both groups. Patients in RDN group had shown a significant improvement in LVEF (P < 0.001), SMWD (P = 0.043), NYHA class (P < 0.001), NT-proBNP (P < 0.001) and office heart rate (P = 0.008). Compared with control group, RDN patients were associated with significant improvement in all domains of SF-36 but bodily pain (P = 0.74). No significant change in estimate glomerular filtration nor complication of renal artery stenosis were observed.

CONCLUSIONS

Results imply that RDN could be safely applied to treatment of HF and probably improve cardiac systolic function and patients' quality of life. © 2016 Wiley Periodicals, Inc.

Autonomic Predictors of Hospitalization Due to Heart Failure Decompensation in Patients with Left Ventricular Systolic Dysfunction

Introduction

Autonomic nervous system balance can be significantly deteriorated during heart failure exacerbation. However, it is still unknown whether these changes are only the consequence of heart failure decompensation or can also predict development thereof. Objectives were to verify if simple, non-invasive autonomic parameters, such as baroreflex sensitivity and short-term heart rate variability can provide independent of other well-known clinical parameters information on the risk of heart failure decompensation in patients with left ventricular systolic dysfunction.

Methods

In 142 stable patients with left ventricular ejection fraction ≤ 40%, baroreflex sensitivity and short-term heart rate variability, as well as other well-known clinical parameters, were analyzed. During 23 ± 9 months of follow-up 19 patients were hospitalized due to the heart failure decompensation (EVENT).

Results

Pre-specified cut-off values of baroreflex sensitivity (≤2.4 ms/mmHg) and low frequency power index of heart rate variability (≤19 ms²) were significantly associated with the EVENTs (hazard ratio 4.43, 95% confidence interval [CI] 1.35–14.54 and 5.41, 95% CI 1.87–15.65 respectively). EVENTs were also associated with other parameters, such as left ventricular ejection fraction, NYHA class, diuretic use, renal function, brain natriuretic peptide and hemoglobin level, left atrial size, left and right ventricular heart failure signs. After adjusting baroreflex sensitivity and low frequency power index for each of the abovementioned parameters, autonomic parameters were still significant predictors of hospitalization due to the heart failure decompensation.

Conclusion

Simple, noninvasive autonomic indices can be helpful in identifying individuals with increased risk of hospitalization due to the heart failure decompensation among clinically stable patients with left ventricular systolic dysfunction, even when adjusted for other well-known clinical parameters.

The pathophysiological role of natriuretic peptide-RAAS cross talk in heart failure

Chronic Heart Failure (HF) is still a disease state characterized by elevated morbidity and mortality and represents an unresolved problem for its socio-economic impact. Besides many of the pathophysiological events leading to advanced HF have been widely disclosed in the past decades, the role of neuro-hormonal dysregulation accompanying HF has to be clearly assessed with the objective of better therapeutic approaches in treating such a disease. In the present review article, alongside with a brief re-evaluation of general aspects of HF physiopathology, we summarize recent advances in the cross talk between renin-angiotensin-aldosterone system (RAAS) with natriuretic peptides (NPs) which have been shown to play a relevant role in the development of severe HF. The role of RAAS-NPs interplay has been shown to be crucial in both hemodynamic and tissue remodeling associated to cardiomyocyte dysfunction, leading to advanced impairment of left ventricular performance. On the basis of these results, the development of drugs resetting both RAAS and NPs system seems to be promising for a successful long term treatment of chronic HF.

Deceleration and acceleration capacities of heart rate associated with heart failure with high discriminating performance

Accurate measurements of autonomic nerve regulation in heart failure (HF) were unresolved. The discriminating performance of deceleration and acceleration capacities of heart rate in HF was evaluated in 130 HF patients and 212 controls. Acceleration capacity and deceleration capacity were independent risk factors for HF in males, evaluated by multiple logistic regression analysis, with odds ratios (ORs) of 5.94 and 0.13, respectively. Acceleration capacity was also an independent risk factor for HF in females, with an OR of 8.58. Deceleration capacity was the best cardiac electrophysiological index to classify HF in males, with an area under the receiver operating characteristic curve (AUC) of 0.88. Deceleration capacity was the best classification factor of HF in females with an AUC of 0.97, significantly higher than even left ventricular ejection fraction (LVEF). Acceleration capacity also showed high performance in classifying HF in males (0.84) and females (0.92). The cut-off values of deceleration capacity for HF classification in males and females were 4.55 ms and 4.85 ms, respectively. The cut-off values of acceleration capacity for HF classification in males and females were −6.15 ms and −5.75 ms, respectively. Our study illustrates the role of acceleration and deceleration capacity measurements in the neuro-pathophysiology of HF.

Heart Failure as a Disruption of Dynamic Circulatory Homeostasis Mediated by the Brain

Circulatory homeostasis is associated with interactions between multiple organs, and the disruption of dynamic circulatory homeostasis could be considered as heart failure. The brain is the central unit integrating neural and neurohormonal information from peripheral organs and controlling peripheral organs using the autonomic nervous system. Heart failure is worsened by abnormal sympathoexcitation associated with baroreflex failure and/or chemoreflex activation, and by vagal withdrawal, and autonomic modulation therapies have benefits for heart failure. Recently, we showed that baroreflex failure induces striking volume intolerance independent of left ventricular dysfunction. Many studies have indicated that an overactive renin-angiotensin system, excess oxidative stress and excess inflammation, and/or decreased nitric oxide in the brain cause sympathoexcitation in heart failure. We have demonstrated that angiotensin II type 1 receptor (AT1R)-induced oxidative stress in the rostral ventrolateral medulla (RVLM), which is known as a vasomotor center, causes prominent sympathoexcitation in heart failure model rats. Interestingly, systemic infusion of angiotensin II directly affects brain AT1R with sympathoexcitation and left ventricular diastolic dysfunction. Moreover, we have demonstrated that targeted deletion of AT1R in astrocytes strikingly improved survival with prevention of left ventricular remodeling and sympathoinhibition in myocardial infarction-induced heart failure. From these results, we believe it is possible that AT1R in astrocytes, not in neurons, have a key role in the pathophysiology of heart failure. We would like to propose a novel concept that the brain works as a central processing unit integrating neural and hormonal input, and that the disruption of dynamic circulatory homeostasis mediated by the brain causes heart failure.

Mechanisms for the cardiovascular effects of glucagon-like peptide-1

Over the past three decades, at least 10 hormones secreted by the enteroendocrine cells have been discovered, which directly affect the cardiovascular system through their innate receptors expressed in the heart and blood vessels or through a neural mechanism. Glucagon-like peptide-1 (GLP-1), an important incretin, is perhaps best studied of these gut-derived hormones with important cardiovascular effects. In this review, I have discussed the mechanism of GLP-1 release from the enteroendocrine L-cells and its physiological effects on the cardiovascular system. Current evidence suggests that GLP-1 has positive inotropic and chronotropic effects on the heart and may be important in preserving left ventricular structure and function by direct and indirect mechanisms. The direct effects of GLP-1 in the heart may be mediated through GLP-1R expressed in atria as well as arteries and arterioles in the left ventricle and mainly involve in the activation of multiple pro-survival kinases and enhanced energy utilization. There is also good evidence to support the involvement of a second, yet to be identified, GLP-1 receptor. Further, GLP-1(9-36)amide, which was previously thought to be the inactive metabolite of the active GLP-1(7-36)amide, may also have direct cardioprotective effects. GLP-1's action on GLP-1R expressed in the central nervous system, kidney, vasculature and the pancreas may indirectly contribute to its cardioprotective effects.

Increased Epicardial Adipose Tissue Volume Correlates With Cardiac Sympathetic Denervation in Patients With Heart Failure

RATIONALE

It has been reported that epicardial adipose tissue (EAT) may affect myocardial autonomic function.

OBJECTIVE

The aim of this study was to explore the relationship between EAT and cardiac sympathetic nerve activity in patients with heart failure.

METHODS AND RESULTS

In 110 patients with systolic heart failure, we evaluated the correlation between echocardiographic EAT thickness and cardiac adrenergic nerve activity assessed by (123)I-metaiodobenzylguanidine ((123)I-MIBG). The predictive value of EAT thickness on cardiac sympathetic denervation ((123)I-MIBG early and late heart:mediastinum ratio and single-photon emission computed tomography total defect score) was tested in a multivariate analysis. Furthermore, catecholamine levels, catecholamine biosynthetic enzymes, and sympathetic nerve fibers were measured in EAT and subcutaneous adipose tissue biopsies obtained from patients with heart failure who underwent cardiac surgery. EAT thickness correlated with (123)I-MIBG early and late heart:mediastinum ratio and single-photon emission computed tomography total defect score, but not with left ventricular ejection fraction. Moreover, EAT resulted as an independent predictor of (123)I-MIBG early and late heart:mediastinum ratio and single-photon emission computed tomography total defect score and showed a significant additive predictive value on (123)I-MIBG planar and single-photon emission computed tomography results over demographic and clinical data. Although no differences were found in sympathetic innervation between EAT and subcutaneous adipose tissue, EAT showed an enhanced adrenergic activity demonstrated by the increased catecholamine levels and expression of catecholamine biosynthetic enzymes.

CONCLUSIONS

This study provides the first evidence of a direct correlation between increased EAT thickness and cardiac sympathetic denervation in heart failure.

The role of heart rate variability in sports physiology

Heart rate variability (HRV) is a relevant marker reflecting cardiac modulation by sympathetic and vagal components of the autonomic nervous system (ANS). Although the clinical application of HRV is mainly associated with the prediction of sudden cardiac death and assessing cardiovascular and metabolic illness progression, recent observations have suggested its applicability to physical exercise training. HRV is becoming one of the most useful tools for tracking the time course of training adaptation/maladaptation of athletes and in setting the optimal training loads leading to improved performances. However, little is known regarding the role of HRV and the internal effects of physical exercise on an athlete, which may be useful in designing fitness programs ensuring sufficient training load that may correspond with the specific ability of the athlete. In this review, we offer a comprehensive assessment of investigations concerning the interrelation between HRV and ANS, and examine how the application of HRV to physical exercise may play a role in sports physiology.

Renal function on admission modifies prognostic impact of diuretics in acute heart failure: a propensity score matched and interaction analysis

Although intravenous diuretics have been mainstay drugs in patients with acute heart failure (AHF), they have been suggested to have some deleterious effects on prognosis. We postulated that renal function may modify their deleterious effects in AHF patients. The study population consisted of 1094 AHF patients from three hospitals. Renal dysfunction (RD) was defined as estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m² on admission, and the cohort was divided into a high-dose furosemide (≥100 mg/48 h) and low-dose furosemide group according to the amount of intravenous furosemide used within 48 h from admission. In the whole cohort, in-hospital mortality rate was higher in the high-dose furosemide group than the low-dose furosemide group (12.5 vs. 6.6 %, respectively, P = 0.001). However, this difference in the in-hospital mortality rates was significant only in the RD subgroup (15.6 vs. 7.0 %, respectively, P < 0.001), and not in the non-RD subgroup (2.5 vs. 5.9 %, respectively, P = 0.384). Propensity score-matched analysis was performed to evaluate the impact of high-dose furosemide on prognosis. After propensity score matching, high-dose furosemide was not associated with in-hospital mortality (OR 1.25, 95 % CI 0.73-2.16, P = 0.408). However, there was a qualitative difference in OR for in-hospital mortality between AHF with RD (OR 1.77, 95 % CI 0.96-3.28, P = 0.068) and without RD (OR 0.23, 95 % CI 0.05-1.10, P = 0.064), and there was a significant interaction between eGFR and prognostic impact of high-dose furosemide (P for OR interaction = 0.013). An inverse relationship was observed between eGFR and OR for in-hospital death in the group treated with high-dose furosemide (decreasing OR with better eGFR). The deleterious effect of diuretics was significantly modified with renal function in AHF. This association may be one reason for poorer prognosis of AHF patients complicated with renal impairment.

Prognostic Value of Lymphocyte G Protein-Coupled Receptor Kinase-2 Protein Levels in Patients With Heart Failure

RATIONALE

Sympathetic nervous system hyperactivity is associated with poor prognosis in patients with heart failure (HF), yet routine assessment of sympathetic nervous system activation is not recommended for clinical practice. Myocardial G protein-coupled receptor kinase-2 (GRK2) is upregulated in HF patients, causing dysfunctional β-adrenergic receptor signaling. Importantly, myocardial GRK2 levels correlate with levels found in peripheral lymphocytes of HF patients.

OBJECTIVE

The independent prognostic value of blood GRK2 measurements in HF patients has never been investigated; thus, the purpose of this study was to evaluate whether lymphocyte GRK2 levels predict clinical outcome in HF patients.

METHODS AND RESULTS

We prospectively studied 257 HF patients with mean left ventricular ejection fraction of 31.4±8.5%. At the time of enrollment, plasma norepinephrine, serum NT-proBNP, and lymphocyte GRK2 levels, as well as clinical and instrumental variables were measured. The prognostic value of GRK2 to predict cardiovascular (CV) death and all-cause mortality was assessed using the Cox proportional hazard model including demographic, clinical, instrumental, and laboratory data. Over a mean follow-up period of 37.5±20.2 months (range, 3-60 months), there were 102 CV deaths. Age, left ventricular ejection fraction, New York Heart Association class, chronic obstructive pulmonary disease, chronic kidney disease, N-terminal-pro brain natriuretic peptide, and lymphocyte GRK2 protein levels were independent predictors of CV mortality in HF patients. GRK2 levels showed an additional prognostic and clinical value over demographic and clinical variables. The independent prognostic value of lymphocyte GRK2 levels was also confirmed for all-cause mortality.

CONCLUSIONS

Lymphocyte GRK2 protein levels can independently predict prognosis in patients with HF.

Drug resistant hypertension – no simple way out

Hypertension poses growing challenge for health policy-makers and doctors worldwide. Recently published results of Symplicity-III trial (HTN-3), the first blinded, randomized, multicenter study on the efficacy of renal denervation for the treatment of resistant hypertension did not show a significant reduction of BP in patients with resistant hypertension 6 months after renal-artery denervation, as compared with controls. In this paper we review clinical and experimental studies on renal denervation. In order to identify causes of inconsistent results in renal denervation studies we look at basic science support for renal denervation and at designs of clinical trials.

Alcohol effects on cardiac function

The consumption of ethanol can have both beneficial and detrimental effects on the function of the heart and cardiovascular system, depending on the amount consumed. Low-to-moderate amounts of ethanol intake are associated with improvements in cardiac function and vascular health. On the other hand, ethanol chronically consumed in large amounts acts as a toxin to the heart and vasculature. The cardiac injury produced by chronic alcohol abuse can progress to heart failure and eventual death. Furthermore, alcohol abuse may exacerbate preexisting heart conditions, such as hypertension and cardiomyopathy. This article focuses on the molecular mechanisms and pathophysiology of both the beneficial and detrimental cardiac effects of alcohol.

Exploration of 6,7-dimethoxyquinazoline derivatives as dual acting α1- and AT1-receptor antagonists: synthesis, evaluation, pharmacophore & 3D-QSAR modeling and receptor docking studies

The 6,7-dimethoxyquinazoline scaffold was further explored to provide dual acting α₁- and AT₁-receptor antagonists by synthesizing a series of derivatives and biologically evaluating the newly synthesized compounds.

Cardiac Adrenergic Nervous System and Left Ventricular Remodeling

Heightened cardiac adrenergic nervous system (ANS) activity and progression of left ventricular (LV) remodeling are temporally related in patients with systolic heart failure. Whether cardiac ANS activation directly contributes to or merely accompanies LV remodeling remains an unresolved issue. Human and experimental data that directly link cardiac ANS activation to LV remodeling and worsening heart failure are first reviewed, including cardiac norepinephrine spillover. Alterations of beta adrenergic receptor signaling pathways are then addressed with emphasis on the mechanisms that may mediate the beneficial effect of beta adrenergic receptor blockade on LV remodeling. Lastly, alternative approaches to beta adrenergic receptor blockade for lessening cardiac ANS activation and reversing cardiac ANS-induced LV remodeling are discussed. A large body of work now links LV remodeling to cardiac ANS activation. However, the precise mechanisms that link cardiac ANS activation to LV remodeling are still to be fully understood. Fully understanding of these mechanisms may uncover new therapeutic approaches.

Upper arm venous compliance and fitness in stable coronary artery disease patients and healthy controls

OBJECTIVES

Arteries have been examined extensively in coronary artery disease (CAD), while less attention has been paid to veins.

AIMS

(1) To determine whether venous compliance or venous outflow in the upper arm is reduced in CAD patients compared to healthy age- and fitness-matched controls; and (2) to examine the association between upper arm venous compliance and total blood volume.

DESIGN

Fifteen patients with stable CAD (age 62·1 ± 5·7 years, body mass index 26·5 ± 3·2 kg·m² , fat-free mass 59·3 ± 7·6 kg, mean arterial pressure 98·9 ± 8·0 mmHg, VO_2peak : 2·92 ± 0·53 l min^-1 ) were compared to twelve healthy age- and fitness-matched controls (age 62·2 ± 3·7 years, body mass index 26·2 ± 2·3 kg m² , fat-free mass 61·0 ± 9·2 kg, mean arterial pressure 96·5 ± 9·1 mmHg, VO_2peak : 3·24 ± 0·48 l min^-1 ). Venous compliance was examined using high-resolution ultrasound and Doppler in the basilic vein. Blood volumes were measured by the optimized CO rebreathing method.

RESULTS

Equal upper arm venous compliance normalized to blood volume (patients: 0·28 ± 0·26 mm³  mmHg^-1  l^-1 , healthy controls: 0·16 ± 0·11 mm³ mmHg^-1  l^-1 ) and peak venous outflow normalized to blood volume (patients: 10·4 ± 3·9 cm s^-1  l^-1 , healthy controls: 8·3 ± 0·8 cm s^-1  l^-1 ) were found in patients with CAD and healthy age- and fitness-matched controls. Additionally, no difference was found in blood volume (patients: 6·06 ± 0·79 l, healthy controls: 6·68 ± 1·27 l) or VO_2peak .

CONCLUSION

Comparable upper arm venous compliance and venous outflow in CAD patients and healthy age- and fitness-matched controls might indicate that high VO_2peak and blood volume could prevent possible disease-induced reductions in venous compliance in CAD.