Prevention of Ventricular Fibrillation, Acute Myocardial Infarction (Myocardial Necrosis), Heart Failure, and Mortality by Bretylium

Role of plasmacytoid dendritic cells in vascular dysfunction in mice with renovascular hypertension

Endothelial dysfunction and inflammation are clinically significant risk factors for cardiovascular diseases in hypertension. Although immune cells play a role in hypertension, the impact of plasmacytoid dendritic cells in established renovascular hypertension-induced cardiovascular complications is not fully understood. We investigated plasmacytoid dendritic cells' contribution to arterial endothelial dysfunction and inflammation in renovascular hypertension. A two-kidney one-clip (2K1C) model for four weeks in both male and female mice was used to induce renovascular hypertension. We treated mice with or without anti-PDCA-1 antibodies for one week to deplete the plasmacytoid dendritic cells. Renovascular hypertension causes cardiac hypertrophy, lung edema, and microvascular endothelial dysfunction associated with inflammation induction in mice. Moreover, renovascular hypertension affects the profile of immune cells, including dendritic cells and macrophages, with variations between male and female mice. Interestingly, the depletion of plasmacytoid dendritic cells significantly reduces blood pressure, cardiac hypertrophy, lung edema, inflammation, and oxidative stress and improves microvascular endothelial function via the endoplasmic reticulum (ER) stress, autophagy, and mTOR-dependent mechanisms. Plasmacytoid dendritic cells significantly contribute to the development of cardiovascular complications in renovascular hypertension by modulating immune cells, inflammation, oxidative stress, and ER stress.

Perioperative Myocardial Infarction in Free Flap for Head and Neck Reconstruction

INTRODUCTION

Acute myocardial infarction (AMI) is a postoperative complication of major surgical procedures, including free flap surgery. It is the most common cause of postoperative morbidity and mortality. Moreover, patients receiving free flap reconstruction for the head and neck have significant risk factors such as coexisting coronary artery disease (CAD). Our primary aim was to ascertain predictors of perioperative AMI to enable early detection and consequently early treatment of perioperative AMI. Our secondary aim was to determine the group of patients who would be at a high risk for perioperative AMI after free flap surgery.

MATERIALS AND METHODS

This retrospective study enrolled patients who underwent free flap reconstruction surgery at the Division of Plastic and Reconstructive Surgery of Taipei Veterans General Hospital between 2013-01 and 2017-12.

RESULTS

This study included 444 patients and 481 free flap head and neck reconstruction surgeries. Fifteen (3.1%) patients were diagnosed with perioperative AMI. Statistical analysis of the variables revealed that patients with underlying CAD or cerebrovascular accident (CVA) were at a high risk of developing perioperative AMI (odds ratio: 6.89 and 11.11, respectively). The flap failure rate was also higher in patients with perioperative AMI compared with those without perioperative AMI (P = 0.015).

CONCLUSIONS

Patients with underlying diseases, such as CAD or CVA, constituted high-risk groups for perioperative AMI.

Functional Gly297Ser Variant of the Physiological Dysglycemic Peptide Pancreastatin Is a Novel Risk Factor for Cardiometabolic Disorders

Pancreastatin (PST), a chromogranin A-derived potent physiological dysglycemic peptide, regulates glucose/insulin homeostasis. We have identified a nonsynonymous functional PST variant (p.Gly297Ser; rs9658664) that occurs in a large section of human populations. Association analysis of this single nucleotide polymorphism with cardiovascular/metabolic disease states in Indian populations (n = 4,300 subjects) displays elevated plasma glucose, glycosylated hemoglobin, diastolic blood pressure, and catecholamines in Gly/Ser subjects as compared with wild-type individuals (Gly/Gly). Consistently, the 297Ser allele confers an increased risk (∼1.3-1.6-fold) for type 2 diabetes/hypertension/coronary artery disease/metabolic syndrome. In corroboration, the variant peptide (PST-297S) displays gain-of-potency in several cellular events relevant for cardiometabolic disorders (e.g., increased expression of gluconeogenic genes, increased catecholamine secretion, and greater inhibition of insulin-stimulated glucose uptake) than the wild-type peptide. Computational docking analysis and molecular dynamics simulations show higher affinity binding of PST-297S peptide with glucose-regulated protein 78 (GRP78) and insulin receptor than the wild-type peptide, providing a mechanistic basis for the enhanced activity of the variant peptide. In vitro binding assays validate these in silico predictions of PST peptides binding to GRP78 and insulin receptor. In conclusion, the PST 297Ser allele influences cardiovascular/metabolic phenotypes and emerges as a novel risk factor for type 2 diabetes/hypertension/coronary artery disease in human populations.

Liposome-encapsulated hemoglobin (HbV) transfusion rescues rats undergoing progressive lethal 85% hemorrhage as a result of an anti-arrhythmogenic effect on the myocardium

Liposome-encapsulated hemoglobin vesicles (HbV) can serve as a blood substitute with oxygen-carrying capacity comparable to that of human blood and lethal hemorrhage is associated with lethal arrhythmias. To investigate the resuscitation effect of HbV on lethal hemorrhage and anti-arrhythmogenesis, we performed optical mapping analysis (OMP) and electrophysiological study (EPS) in graded blood exchange (85% blood loss) in the rat model. We also measured cardiac autonomic activity, as assessed by heart rate variability (HRV), and changes in plasma norepinephrine and left ventricle ejection fraction (LVEF) by echocardiography. Pathological study on Connexin43 was performed. A 5% albumin (ALB group), washed rat erythrocytes (wRBC group), and HbV (HbV group) were used as a resuscitation fluid. The survival effects over 24 hours were examined. All rats died in the ALB group, whereas almost all survived for 24-hours period in wRBC and HbV groups. OMP showed impaired action potential duration dispersion (APDd) in the ALB group, whereas normal APDs in HbV and wRBC groups. Lethal arrhythmias were induced by EPS in the ALB group, but not in wRBC and HbV groups. HRV indices, LVEF, Connexin43 were preserved in HbV and wRBC groups. Lethal hemorrhage causes lethal arrhythmias in the presence of impaired APDd. HbV acutely rescues lethal hemorrhage by preventing lethal arrhythmias and preserving arrhythmogenic factors.

Bretylium, a Class III Antiarrhythmic, Returns to the Market

Bretylium, with an extensive pharmacologic and medicinal history, was approved by the United States Food and Drug Administration in 1986 for "short-term prevention and treatment of ventricular fibrillation (VF) and treatment of life-threatening ventricular arrhythmias and ventricular tachycardia (VT) unresponsive to adequate doses of a first-line antiarrhythmic agent, such as lidocaine." The NDA sponsor withdrew bretylium from the market in 2011, largely due to unavailability of raw materials required for its production; prior to this, bretylium was removed from the 2000 ACLS Guidelines algorithm for VF/pulseless VT given the challenges obtaining raw materials for drug manufacture. Recently, bretylium has been reintroduced into the US market by a generic pharmaceutical company with the same indications as before. This article provides a history of the salient trials evaluating the efficacy and safety of bretylium and looks to the future as bretylium finds its place in the modern day management of ventricular arrhythmia.

What is New in Pharmacologic Therapy for Cardiac Resuscitation?

Antiarrhythmic therapy can be a critical component of cardiac resuscitation. Therapies in this area have seen little advance in the last decade. Bretylium, a very old drug, has been reintroduced for ventricular tachycardia/ventricular fibrillation (VT/VF) therapy. There are still important questions to be addressed with bretylium: when to administer (first- or second-line) and at which dose. These questions and the development of newer agents will be areas of future research.

The Protective Mechanism of Cannabidiol in Cardiac Injury: A Systematic Review of Non-Clinical Studies

Background:

Cardiac disease is accounted as the leading cause of worldwide morbidity and mortality. The disease is characterized by the overproduction of reactive oxygen and/or nitrogen species (ROS/RNS), and induction of oxidative stress. Cannabidiol (CBD) is a non-psychoactive ingredient of marijuana that has been reported to be safe and well tolerated in patients. Due to its pleiotropic effect, CBD has been shown to exert cytoprotective effects. This study intended to clarify the mechanisms and the potential role of CBD regarding cardiac injuries treatment.

Methods:

A systematic literature search was conducted, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, in the electronic databases including PubMed, Web of Science, Scopus, and Embase up to June 2019 using predefined search terms in the titles and abstracts. Accordingly, a set of pre-specified inclusion and exclusion criteria were considered and 8 articles were ultimately included in this study.

Results:

Our findings demonstrate that CBD has multi-functional protective assets to improve cardiac injuries; preliminary through scavenging of free radicals, and reduction of oxidative stress, apoptosis, and inflammation.

Conclusion:

CBD can protect against cardiac injuries, mainly through its antioxidative and antiapoptotic effects on the basis of non-clinical studies. The cardioprotective effects of the CBD need to be further studied in welldesigned clinical trials.

Decreased circulating catestatin levels are associated with coronary artery disease: The emerging anti-inflammatory role

BACKGROUND AND AIMS

The neuropeptide catestatin (CST) is an endogenous nicotinic cholinergic antagonist that acts as pleiotropic cardiac protective hormone. This study investigated the association between CST and coronary artery disease (CAD) and the underlying mechanisms.

METHODS AND RESULTS

The serum concentration of CST among 224 CAD patients and 204 healthy controls was compared, and its association with atherosclerosis severity in 921 CAD patients was further analyzed. Compared to healthy subjects, serum CST concentration was lower in patients with CAD [1.14 (1.05-1.24) ng/mL vs. 2.15 (1.92-2.39) ng/mL, p < 0.001] and was inversely correlated with disease severity (r = -0.208, p < 0.001). In cultured endothelial cells, CST suppressed TNF-α-elicited expression of inflammatory cytokines and adhesion molecules by activating angiotensin-converting enzyme-2 (ACE2). Administration of CST reduced leukocyte-endothelium interactions in vitro and in vivo, and attenuated the development of atherosclerotic in ApoE^-/- mice fed a high-fat diet. These protective effects by CST were blocked by an ACE2 inhibitor.

CONCLUSIONS

Serum CST concentration is lower in CAD patients and is inversely associated with the severity of atherosclerosis. CST acts as a novel anti-atherogenic peptide that inhibits inflammatory response and EC-leukocyte interactions via an ACE2-dependent mechanism.

Treg cells depletion is a mechanism that drives microvascular dysfunction in mice with established hypertension

BACKGROUND

Microvascular dysfunction is a major complication in hypertensive patients. We previously reported that CD4⁺CD25⁺ T regulatory cells (Treg) play an important preventive role in hypertension-induced vascular dysfunction. However, whether Treg cells therapy and autophagy inhibition could rescue Treg cells survival and microvascular function in established hypertension is an important question that remained unanswered.

METHODS & RESULTS

Here we showed that Treg cells from mice model of established hypertension displayed an enhanced apoptotic rate, which was rescued with Treg cells transfer and autophagy inhibition. We also showed increased autophagy in mesenteric resistance artery (MRA) in mice with established hypertension. Importantly, the inhibition of autophagy or one single transfer of Treg cells into mice with established hypertension improved the microvascular function independently of high blood pressure. The protection involves the modulation of interleukin-10 (IL-10), inflammation, endoplasmic reticulum (ER) stress, oxidative stress, Akt, and eNOS.

CONCLUSIONS

The present study suggests that Treg cells survival is regulated by autophagy. Also, Treg cells as a cellular therapy aimed at rescuing the microvascular function through an autophagy-dependent mechanism and independently of arterial blood pressure lowering effects. Because our mouse model of established hypertension mimics the clinical situation, our results have the potential for new therapeutic approaches that involve the manipulation of Treg cells and autophagy to overcome established hypertension-induced cardiovascular complications.

Cardioprotective Effects of Curcumin-Nisin Based Poly Lactic Acid Nanoparticle on Myocardial Infarction in Guinea Pigs

Myocardial infarction (MI) is the most prevalent cause of cardiovascular death. A possible way of preventing MI maybe by dietary supplements. The present study was thus designed to ascertain the cardio-protective effect of a formulated curcumin and nisin based poly lactic acid nanoparticle (CurNisNp) on isoproterenol (ISO) induced MI in guinea pigs. Animals were pretreated for 7 days as follows; Groups A and B animals were given 0.5 mL/kg of normal saline, group C metoprolol (2 mg/kg), groups D and E CurNisNp 10 and 21 mg/kg respectively (n = 5). MI was induced on the 7^th day in groups B-E animals. On the 9^th day electrocardiogram (ECG) was recorded, blood samples and tissue biopsies were collected for analyses. Toxicity studies on CurNisNp were carried out. MI induction caused atrial fibrillation which was prevented by pretreatment of metoprolol or CurNisNp. MI induction was also associated with increased expressions of cardiac troponin I (CTnI) and kidney injury molecule-1 (KIM-1) which were significantly reduced in guinea pig's pretreated with metoprolol or CurNisNp (P < 0.05). The LC₅₀ of CurNisNp was 3258.2 μg/mL. This study demonstrated that the formulated curcumin-nisin based nanoparticle confers a significant level of cardio-protection in the guinea pig and is nontoxic.

Ivabradine has a neutral effect on mortality in randomized controlled trials

BACKGROUND

It has long been a controversial hotspot whether resting heart rate (RHR) is a risk factor or a marker for death. Ivabradine, a specific inhibitor of the If current in the sinoatrial node, is a pure RHR lowering agent. The study was aimed to investigate whether ivabradine would reduce more RHR, cardiovascular disease (CVD) mortality, and all-cause mortality than those placebo or beta-blockers.

METHODS

The authors performed a meta-analysis of 8 randomized controlled clinical studies (with 40,357 participants), and 3 studies of those which were ivabradine versus placebo (36,069 participants) and other 5 studies ivabradine versus beta-blockers (4288 participants) were available. The authors compared the association of the RHR reduction with death from CVD causes (2674 in 40,285 participants) and the rate of all-cause death (3143 deaths in 38,037 participants), and assessed improvement in death rates with the use of ivabradine.

RESULTS

The change of RHR from baseline to endpoint was 8 to 16 beats/min (bpm) in ivabradine group, 1 to 8 bpm in placebo group, and 4 to 24 bpm in beta-blockers group. In ivabradine versus placebo, the reduced risks of CVD mortality and all-cause morbidity were not significantly (risk ratio [RR] 1.02; 95% confidence interval [CI] 0.91-1.14, P = .737; RR: 1.00, 95% CI: 0.92-1.09, P = .992, respectively). CVD and all-cause morbidity were similar for ivabradine versus beta-blockers (RR: 1.04; 95% CI: 0.80-1.37, P = .752; RR: 1.17, 95% CI: 0.53-2.60, P = .697, respectively).

CONCLUSIONS

Ivabradine had a neutral effect on mortality, suggesting that a pure RHR lowering agent did not reduce CVD mortality, all-cause mortality and improve the lifespan.

Determination of risk factors affecting the in-hospital prognosis of patients with acute ST segment elevation myocardial infarction after percutaneous coronary intervention

BACKGROUND

To determine the factors affecting the in-hospital prognosis of patients with acute ST segment elevation myocardial infarction (STEMI) after percutaneous coronary intervention (PCI), and to establish its prognostic discriminant model.

METHODS

A total of 701 consecutive STEMI patients undergoing PCI were enrolled in this study. The patients were divided into two groups, good prognosis and poor prognosis, based on whether the patient had adverse outcomes (death or heart function ≥ grade III) at discharge. Demographic and basic clinical characteristics, diagnosis at admission (e.g., ventricular function, complications, or hyperlipidemia), and biomedical indicators (e.g., blood count, basal metabolism and biochemical composition, blood lipid and glucose levels, myocardial biomarkers, and coagulation) were collected and analyzed.

RESULTS

We determined 22 factors as risk factors for the in-hospital prognosis of STEMI patients after PCI: age, cardiac function during hospitalization, complications, history of diabetes mellitus, et al., among which the history of diabetes, uric acid, urea nitrogen, and activated partial thromboplastin time (APTT) were independent risk factors.

CONCLUSION

We identified four independent risk factors for the in-hospital prognosis of STEMI patients after PCI and generated a prognostic model to predict the adverse outcomes of these patients.

Granin-derived peptides

The granin family comprises altogether 7 different proteins originating from the diffuse neuroendocrine system and elements of the central and peripheral nervous systems. The family is dominated by three uniquely acidic members, namely chromogranin A (CgA), chromogranin B (CgB) and secretogranin II (SgII). Since the late 1980s it has become evident that these proteins are proteolytically processed, intragranularly and/or extracellularly into a range of biologically active peptides; a number of them with regulatory properties of physiological and/or pathophysiological significance. The aim of this comprehensive overview is to provide an up-to-date insight into the distribution and properties of the well established granin-derived peptides and their putative roles in homeostatic regulations. Hence, focus is directed to peptides derived from the three main granins, e.g. to the chromogranin A derived vasostatins, betagranins, pancreastatin and catestatins, the chromogranin B-derived secretolytin and the secretogranin II-derived secretoneurin (SN). In addition, the distribution and properties of the chromogranin A-derived peptides prochromacin, chromofungin, WE14, parastatin, GE-25 and serpinins, the CgB-peptide PE-11 and the SgII-peptides EM66 and manserin will also be commented on. Finally, the opposing effects of the CgA-derived vasostatin-I and catestatin and the SgII-derived peptide SN on the integrity of the vasculature, myocardial contractility, angiogenesis in wound healing, inflammatory conditions and tumors will be discussed.

Plasma Catestatin in Patients with Acute Coronary Syndrome

OBJECTIVES

To measure plasma catestatin levels in patients with acute coronary syndrome and investigate whether there is an association between catestatin levels and long-term outcome.

METHODS

Patients (n = 170) with suspected acute coronary syndrome who underwent emergency coronary angiography were enrolled, including 46 with acute ST-segment elevation myocardial infarction (STEMI), 89 with unstable angina pectoris (UAP), and 35 without coronary artery disease (CAD). All patients were followed for 2 years to measure the occurrence of major adverse cardiovascular events (MACEs), including death from a cardiovascular cause, recurrent acute myocardial infarction, or hospital admission for heart failure or revascularization.

RESULTS

On average, the plasma catestatin levels in patients with STEMI (0.80 ± 0.62 ng/ml) and UAP (0.99 ± 0.63 ng/ml) were significantly lower than the levels seen in the control group with no evidence of CAD (1.38 ± 0.98 ng/ml; p = 0.001). In multivariable linear regression, body mass index, presence of hypertension, and type of CAD were independently related to the plasma catestatin level. However, there were no significant differences in MACEs between patients with high and low levels of catestatin.

CONCLUSIONS

The plasma catestatin levels in patients with STEMI and UAP were lower than the levels seen in patients without CAD.

Alpha-linolenic acid protects against cardiac injury and remodelling induced by beta-adrenergic overstimulation

α-Linolenic acid (ALA)-enriched diet prevented isoproterenol (ISO)-induced fibrosis in the ventricular myocardium.

Noradrenaline transmission reducing drugs may protect against a broad range of diseases

1 A growing body of evidence suggests that the signalling molecule, noradrenaline (NA), plays a pathophysiological role in a broad range of psychiatric, neurological and peripheral disorders. Both preclinical and clinical data suggest that elevated NA signalling may be involved in the aetiology of major diseases such as depression, Alzheimer's disease and diabetes mellitus. 2 The molecular pathways by which NA may cause the manifestation of disease remain poorly understood, although they may include G protein-coupled receptor modulation of the Ras/MAP kinase, Stat3 and PI3K pathways, among others. In both individual animals and humans, NA tone may be elevated largely due to genetics, but also because of the exposure to marked psychological stress or trauma, or other environmental factors. 3 As NA is involved in the 'fight or flight' response by the sympathetic nervous system, this transmitter may be elevated in a large number of organisms due to evolutionary selection of enhancing responses to immediate environmental dangers. Likewise, acetylcholine signalling by the parasympathetic ('rest and digest') nervous system may be relatively diminished. This putative autonomic imbalance may result in diminished engagement in homeostatic processes, resulting in the emergence and progression of a number of diseases throughout the body. 4 In this scenario, a large number of individuals may benefit from chronic use of pharmacological agents - such as clonidine, guanfacine, propranolol or prazosin - that diminish NA signalling throughout the body. If so, NA transmission lowering drugs may protect against a wide range of diseases.

The biology of neurotrophins: cardiovascular function

This chapter addresses the role of neurotrophins in the development of the heart, blood vessels, and neural circuits that control cardiovascular function, as well as the role of neurotrophins in the mature cardiovascular system. The cardiovascular system includes the heart and vasculature whose functions are tightly controlled by the nervous system. Neurons, cardiomyocytes, endothelial cells, vascular smooth muscle cells, and pericytes are all targets for neurotrophin action during development. Neurotrophin expression continues throughout life, and several common pathologies that impact cardiovascular function involve changes in the expression or activity of neurotrophins. These include atherosclerosis, hypertension, diabetes, acute myocardial infarction, and heart failure. In many of these conditions, altered expression of neurotrophins and/or neurotrophin receptors has direct effects on vascular endothelial and smooth muscle cells in addition to effects on nerves that modulate vascular resistance and cardiac function. This chapter summarizes the effects of neurotrophins in cardiovascular physiology and pathophysiology.

Myocardial sympathetic innervation, function, and oxidative metabolism in non-infarcted myocardium in patients with prior myocardial infarction

OBJECTIVE

The purpose of this study was to investigate the relationship between sympathetic innervation, contractile function, and the oxidative metabolism of the non-infarcted myocardium in patients with prior myocardial infarction.

METHODS

In 19 patients (14 men, 5 women, 65 ± 9 years) after prior myocardial infarction, sympathetic innervation was assessed by (11)C-hydroxyephedrine (HED) positron emission tomography (PET). Oxidative metabolism was quantified using (11)C-acetate PET. Left ventricular systolic function was measured by echocardiography with speckle tracking technique.

RESULTS

The (11)C-HED retention was positively correlated with left ventricular ejection fraction (LVEF) (r = 0.566, P < 0.05), and negatively with peak longitudinal strain in systole in the non-infarcted myocardium (r = -0.561, P < 0.05). Kmono, as an index of oxidative metabolism, was significantly correlated with rate pressure product (r = 0.649, P < 0.01), but not with (11)C-HED retention (r = 0.188, P = 0.442). Furthermore, there was no significant correlation between Kmono and LVEF (r = 0.106, P = 0.666) or peak longitudinal strain in systole (r = -0.256, P = 0.291) in the non-infarcted myocardium. When the patients were divided into two groups based on the median value of left ventricular end-systolic volume index (LVESVI) (41 mL), there were no significant differences in age, sex, and rate pressure product between the groups. However, the large LVESVI group (>41 mL) was associated with reduced (11)C-HED retention and peak longitudinal strain in systole, whereas Kmono was similar between the groups.

CONCLUSIONS

This study indicates that remodeled LV after myocardial infarction is associated with impaired sympathetic innervation and function even in the non-infarcted myocardial tissue. Furthermore, oxidative metabolism in the non-infarcted myocardium seems to be operated by normal regulatory mechanisms rather than pre-synaptic sympathetic neuronal function.

Dramatic changes in catestatin are associated with hemodynamics in acute myocardial infarction

Acute myocardial infarction (AMI) is characterized by complex neuroendocrine activation. To investigate catestatin profiles, serial catestatin levels were determined by enzyme-linked immunosorbent assay in the first week after AMI in 50 patients. Catestatin levels reduced at admission and negatively correlated with heart rates; it increased significantly on the third day but remained decreased at 1 week and positively with blood pressure. In a subgroup of 20 patients admitted within 4 h after onset, circulating catestatin correlated inversely with norepinephrine. Catestatin might be involved in the course of AMI and act as a tool in monitoring the progression of AMI.

Cholesterol depletion enhances adrenergic signaling in cardiac myocytes

Cardiac myocytes endogenously express α and β adrenergic receptors, prototypes of the G-protein coupled receptor superfamily. Depending upon the dose of norepinephrine (agonist) exposure, hypertrophy and apoptosis are initiated by differential induction of two discrete constituents of the transcription factor AP-1, i.e., FosB and Fra-1. We explored differential adrenergic signaling as a paradigm for understanding how cholesterol dictates cells to choose hypertrophy or apoptosis. For this, we used fosB and fra-1 promoter-reporter constructs for monitoring adrenergic signaling. We show that cholesterol depletion enhances norepinephrine-mediated signaling in cardiac myocytes. Importantly, this increased signaling is reduced to original level upon cholesterol replenishment. We used specific ligands for α and β adrenergic receptors and show that the enhanced signaling upon cholesterol depletion is a combined effect of both α and β adrenergic receptors. These results constitute the first report demonstrating the effect of cholesterol on adrenergic signaling using a direct end-point gene expression.

Factors related to silent myocardial damage in hemodialysis patients

BACKGROUND

Both traditional and non-traditional risk factors play a role for the development of cardiovascular disease in hemodialysis patients. However, a specific relationship between these risk factors and silent myocardial damage is unknown.

METHODS

Demographic, anthropometric, clinical, and laboratory data were collected. Silent myocardial damage was defined by elevated cardiac troponin I values above cutoff values.

RESULTS

In total, 113 hemodialysis patients were included. Cardiac troponin I concentrations were below cutoff value (<2.3 ng/mL) in 103 (91.2%) patients (Group 1), whereas 10 (8.8%) patients had elevated concentrations (Group 2). Group 1 patients had higher levels of hemoglobin (p = 0.002) and high-density lipoprotein cholesterol (p = 0.002) and lower C-reactive protein (p = 0.003) and tumor necrosis factor-alpha (p = 0.005) levels, as well as less incidence of left ventricular hypertrophy (p = 0.045), when compared to Group 2 patients. Diabetes mellitus (Beta = +0.160, p = 0.021), left ventricular hypertrophy (Beta = +0.247, p < 0.0001), uncontrolled blood pressure (Beta = +0.170, p = 0.016), normalized protein equivalent of total nitrogen appearance (Beta = -0.230, p = 0.001), hemoglobin (Beta = -0.302, p < 0.0001), and tumor necrosis factor-alpha (Beta = +0.506, p < 0.0001) were found to be independently associated with cardiac troponin I levels in multiple linear regression analysis.

CONCLUSIONS

Both traditional and non-traditional risk factors are related with silent myocardial damage, which is considered to an antecedent of major cardiovascular events. Hemodialysis patients, even when asymptomatic, must be closely followed up for the presence of these risk factors.

Plasma catecholamines and ischemic heart disease

Plasma levels of norepinephrine and epinephrine were measured in 84 patients aged 56 +/- 9 (mean +/- SD) years with chronic ischemic heart disease (IHD), anterior acute myocardial infarction (AMI), posterior AMI, acute or chronic IHD associated with various types of electrical instability and in the control subjects. During the first day of hospitalization, plasma epinephrine levels were higher in patients with AMI in both localizations and chronic IHD in comparison with control values. There were no significant differences in plasma epinephrine levels among these groups of patients. However, in the same time period, plasma norepinephrine concentrations in patients with chronic IHD and posterior AMI did not differ from the control values; in patients with anterior AMI they reached by approximately 60% higher values than in the control group. Moreover, all myocardial lesions showing different types of electrical instability were associated with increased plasma levels of both norepinephrine and epinephrine. In conclusion, high plasma levels of epinephrine may result from sympathoadrenal activation. High plasma levels of norepinephrine in patients with anterior AMI and no change in patients with posterior AMI suggest a rather myocardial than an extramyocardial origin of plasma norepinephrine level in anterior AMI. Norepinephrine released from the ischemic area might contribute to the electrical instability of the myocardium and generation of dysrrhythmias.

Altered Autonomic Cardiac Control Predicts Restenosis After Percutaneous Coronary Intervention

BACKGROUND

Early and late restenosis in up to 30% remains a major problem for long-term success after percutaneous coronary intervention (PCI). Compared to bare metal stents, the use of drug-eluting stents reduces restenosis below 10%, but implant coasts have to be considered. In restenosis noninvasive testing lacks diagnostic power. We applied a new approach to identify patients with a high risk for restenosis after PCI by combining heart rate (HR) and blood pressure variability (BPV) analyses.

METHODS

In 52 patients with clinical suspicion of restenosis and history of PCI, we investigated patterns of cardiovagal autonomic regulation prior to cardiac catheterization. The patients were separated in (i) patients with restenosis (CAD+R) and (ii) patients without restenosis (CAD-R), where restenosis is defined as a stenosis greater than 75% of luminal diameter in at least one main vessel. The following parameters/methods were evaluated: Canadian Cardiovascular Society grade (CCS-grade), vessel disease score (CAD-level), left ventricular ejection fraction (LVEF), heart rate variability (HRV), BPV, baroreflex sensitivity (BRS), as well as HR turbulence and blood pressure (BP) potentiation caused by premature ventricular complexes.

RESULTS

Whereas age, LVEF, CAD-level, CCS-grade, and mean BP did not differ between CAD+R and CAD-R, significant differences were found in (i) BPV: diastolic LF/P, systolic, and diastolic UVLF, (ii) in BRS: slope of tachycardic sequences, and (iii) in extrasystolic parameters: heart rate turbulence onset (HRTO) and potentiation of systolic BP (SBPP). Standard HRV parameters did not show significant differences between the groups. Using the two parameters diastolic LF/P (threshold >0.2) and HRTO (threshold >0) restenosis were predicted in 83.4%.

CONCLUSIONS

These results demonstrate that indicators of sympathetic activation or vagal depression identify restenosis in patients after PCI, thus opening a perspective for a new noninvasive monitoring.

Brief stimulation of the peroneal nerve attenuates the exercise pressor reflex in anaesthetised cats

We recently demonstrated that applying capsaicin to the common peroneal nerve, thereby activating small diameter afferent neurons, caused a substantial rise in mean arterial pressure (MAP) and heart rate (HR) that lasted approximately 20 min. In addition, this application of capsaicin transiently attenuated the exercise pressor reflex (EPR). The purpose of the current study was to test the hypothesis that stimulating the peroneal nerve at an intensity that activated both myelinated and unmyelinated axons for a short duration (1 min) causes a similar attenuation of the EPR. Cats were anaesthetised with alpha-chloralose and urethane, the popliteal fossa was exposed, and static contraction was induced by stimulating the tibial nerve. The ipsilateral peroneal nerve was cut and placed on a stimulating electrode. Prior to peroneal nerve stimulation, static contraction of the triceps surae muscle for 1 min increased MAP 48+/-8 mmHg and HR 16+/-3 bpm. Electrical stimulation of the central end of the cut peroneal nerve for 1 min (100 x motor threshold; 40 Hz; 0.1 ms) increased MAP and HR by 62+/-11 mmHg and 28+/-4 bpm, respectively. These increases returned to prestimulation levels within 1 min. Two minutes after the peroneal stimulation was stopped, the EPR was markedly reduced as muscle contraction increased MAP and HR by 20+/-4 mmHg and 7+/-2 bpm, respectively. Repeating the muscle contraction approximately 25 min after peroneal stimulation increased MAP and HR by 38+/-8 mmHg and 12+/-2 bpm, indicating some recovery of the EPR. These results show that brief (1 min) electrical stimulation of afferent neurons in the peroneal nerve attenuates the EPR. This supports the hypothesis that strong activation of small diameter afferent neurons stimulates a nervous system mechanism that diminishes the sensory input from skeletal muscle involved in cardiovascular regulation.