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Results 451 - 500 of 1284
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Goldstein David S - - 2004
Many concepts about acute and chronic effects of stress depend on alterations in sympathetic nerves supplying the heart. Physiologic, pharmacologic, and neurochemical approaches have been used to evaluate cardiac sympathetic function. This article describes a fourth approach that is based on nuclear scanning to visualize cardiac sympathetic innervation and function ...
Goncalvesova Eva - - 2004
Heart transplantation (HTx) is an accepted treatment for precisely defined patients with chronic congestive heart failure; however, as a result of the procedure, the graft is completely denervated. Our study focused on the catecholamine biosynthetic pathway, that is, the production of epinephrine, which is known to have positive chronotropic and ...
Rubinger Dvora - - 2004
BACKGROUND: The pathogenesis of haemodialysis-induced hypotension is multifactorial and may include autonomic nervous system dysfunction. The present study was undertaken to (i) determine heart rate variability (HRV) in chronic haemodialysis patients without and with haemodynamic instability (hypotension-prone) during ultrafiltration and (ii) identify patients at risk and the predictors of dialysis-related ...
Middlekauff Holly R - - 2004
Few clinical studies evaluating the efficacy of acupuncture in heart failure have been performed. These studies have focused on the acupoint Neiguan (P6) in patients experiencing heart failure and have variably reported either an acute increase in ventricular contractility and/or relaxation or no effect on ventricular contractility and/or relaxation. To ...
Acharya R - - 2004
The heart rate is a non-stationary signal, and its variation can contain indicators of current disease or warnings about impending cardiac diseases. The indicators can be present at all times or can occur at random, during certain intervals of the day. However, to study and pinpoint abnormalities in large quantities ...
Tambara Keiichi - - 2004
Reclining in the right lateral decubitus position in chronic heart failure (CHF) is a self-protective mechanism for normalizing impaired cardiac autonomic nervous activity (CANA). Candesartan, an angiotensin II receptor blocker, exerts beneficial effects on CANA and postural preferences in patients with CHF. We studied 15 patients with CHF due to ...
Wranicz Jerzy Krzysztof - - 2004
BACKGROUND: Although the relationship between sex steroid levels and coronary artery disease (CAD) has been the subject of many studies there are still controversies concerning the role of sex steroids in CAD. In patients with CAD, especially after a myocardial infarction, there is evidence for autonomic nervous system dysfunction. However, ...
Hadase Mitsuyoshi - - 2004
BACKGROUND: The present study examined whether the very low frequency (VLF) power of heart rate variability (HRV) is predictive of clinical prognosis in patients with congestive heart failure (CHF). METHOD AND RESULTS: The study recruited 54 consecutive CHF patients with emergency admission because of exacerbation of pulmonary congestion. Holter monitoring ...
Chowdhary Saqib - - 2004
Cardiac parasympathetic activity reduces susceptibility to potentially lethal ventricular arrhythmias in heart failure and ischemic heart disease. This influence is mediated in large part by antagonism of the adverse cardiac effects of sympathetic overactivity ("indirect" parasympathetic activity) in addition to the "direct" effects of muscarinic stimulation. Nitric oxide modulates parasympathetic ...
Friedman Howard S - - 2004
The purpose of this investigation was to determine whether heart rate variability (HRV) in atrial fibrillation (AF) can be related to any echocardiographic-derived measurements of cardiac dimensions or function. AF is characterized by marked HRV. Although HRV in normal sinus rhythm has been studied and shown to have important clinical ...
Fauchier Laurent - - 2004
The decrease in heart rate variability (HRV) might be related to the hemodynamic status in heart failure. However, HRV in patients with severe isolated right heart failure has not been extensively studied. This study compared HRV in patients with congestive heart failure (CHF) and in patients with isolated right heart ...
Schwab J O - - 2004
METHODS: Time and frequency domain analysis were conducted during a period of 600 s each. We performed a special protocol consisting of five different "pacing" periods: 1) recording of normal sinus rhythm (SR1); 2) atrial pacing with a rate 15% higher than the intrinsic heart rate; 3) ventricular pacing triggered ...
Arora Rishi - - 2004
Diastolic heart failure accounts for up to 40% of patients with congestive heart failure (CHF), and is associated with a better prognosis as compared to patients with systolic dysfunction. Nevertheless, patients with diastolic dysfunction have a significantly higher mortality as compared to the normal population. Reduced heart rate variability (HRV), ...
Gray Alrich L - - 2004
Intracardiac pathways mediating the parasympathetic control of various cardiac functions are incompletely understood. Several intracardiac ganglia have been demonstrated to potently influence cardiac rate [the sinoatrial (SA) ganglion], atrioventricular (AV) conduction (the AV ganglion), or left ventricular contractility (the cranioventricular ganglion). However, there are numerous ganglia found throughout the heart ...
Costoli Tania - - 2004
Repeated single exposures to social stressors induce robust shifts of cardiac sympathovagal balance toward sympathetic dominance both during and after each agonistic interaction. However, little evidence is available regarding possible persistent pathophysiological changes due to chronic social challenge. In this study, male CD-1 mice (n = 14) were implanted with ...
Meyer S - - 2004
Autonomic nervous system dysfunction is a common complication of ischemic stroke. Clinical and experimental data indicate hemispheric lateralization in the control of autonomic activity. The insular cortex has also been shown to play a crucial role in the central autonomic network. The aim of this study was to assess cardio-autonomic ...
Yeragani Vikram K - - 2004
In this study, we analyzed heart rate variability during sexual activity using complex demodulation, which is a useful technique to study continuous changes in different frequency bands over short periods of time. Complex demodulation has the advantage of having higher time resolution compared to spectral analysis. We quantified the low ...
Odreman Rodolfo O - - 2004
BACKGROUND: We studied the heart rate responses to the Valsalva maneuver in eight patients with documented past medical history of acute Chagas' disease. METHODS: Four patients were studied 8-21 months after the acute episode and four, 58-68 months thereafter (age 25+/-8.65 years M+/-S.D.). Seventeen healthy subjects of similar age were ...
Villar Juan C - - 2004
BACKGROUND: Although impaired cardio-vagal response characterizes full-blown Chagas' disease, this feature among otherwise healthy T. cruzi serology carriers (SERO[+]) requires confirmation. The purpose of this study was to determine whether abnormal cardio-vagal responses were different among SERO[+] subjects with varying ECG alterations. METHODS: We assessed cardio-vagal reflex response in 57 ...
Agelink Marcus W - - 2004
Numerous studies provide evidence that major depression (MD) is associated with certain disorders of cardiac autonomic nervous system (ANS) function, in particular, with an autonomic neurocardiac imbalance characterized by a low cardiovagal modulation, a raised sympathetic nerve activity and a high resting heart rate. We assume that such MD-associated cardiac ...
Kishi F - - 2004
Mitral valve prolapse (MVP) is closely related to myocardial sympathetic nerve function. This study evaluated the presence of impaired myocardial sympathetic nerve function by Iodine-123-metaiodobenzylguanidine (MIBG) scintigraphy in ten patients with MVP. For comparison, 15 healthy subjects without heart disease were investigated (control group). Single photon emission computed tomography (SPECT) ...
Dobrzycki S - - 2004
PURPOSE: Assessment of the gastroesophageal reflux disease (GERD) influence on myocardial ischemia and autonomic nervous system (ANS) activity. MATERIAL AND METHODS: In 50 patients with angiographically confirmed ischemic heart disease (IHD) in I-III CCS class, simultaneous 24-hour ECG and esophageal pH-metry monitoring was performed. We assessed: (1) GERD occurrence in ...
Alan Sait - - 2004
The purpose of this study is to examine clinical progress and hemodynamic and electrocardiologic features (QT depression and heart rate variability [HRV]) of patients exposed to a scorpion bite. Seventeen patients bitten by scorpions, and, as a control group, 15 healthy subjects were included in the study. Standard electrocardiograph (ECG) ...
Aydin Mustafa - - 2004
To analyze the function of cardiac autonomic regulation in patients with obstructive sleep apnea syndrome (OSAS), we enrolled 36 patients with OSAS and divided them according to the apnea hypopnea index (AHI) into 2 groups: Group I (n=19) had mild OSAS (AHI < 20) and Group II (n=17) had severe ...
Majamaa-Voltti Kirsi - - 2004
BACKGROUND: Patients with the 3243A > G mutation in mitochondrial DNA (mtDNA) have an increased risk for cardiovascular morbidity and mortality. The function of the autonomic nervous system has not been evaluated in these patients. PATIENTS AND METHODS: Indices of 24-hour heart rate variability (HRV) and baroreflex sensitivity (BRS) were ...
Bickel Amitai - - 2004
BACKGROUND: The creation of positive pressure pneumoperitoneum (PP) may lead to adverse cardiovascular effects during laparoscopic operations. It can also lead to increased sympathetic cardiac activity, that might have serious consequences. We hypothesized that by reversing the hemodynamic effects, the use of intermittent sequential pneumatic compression device (Lympha-press) on the ...
Laciar E E Dept. ESAII, CREB, Universitat Politècnica de Catalunya, Barcelona, - - 2004
The aim of this paper is to analyze the beat-to-beat variability of ventricular late potentials (LP) in high resolution ECG (HRECG) records of patients with Chagas' disease. In order to evaluate the LP activity, we propose a method which computes the bi-dimensional (2-D) cross-correlation between a template spectro-temporal (STM) of ...
Verrier Richard L RL Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, - - 2004
Recent progress in understanding the role of the autonomic nervous system in the development of cardiac arrhythmias is reviewed. The focus is on the translation of basic principles of neural control of heart rhythm that have emerged from experimental studies to clinical applications. Recent studies have made significant strides in ...
O'Leary Deirdre M - - 2003
The fibre types that run in a vagal branch projecting to the rat heart are described in this study. In order to obtain spontaneous discharge in this vagal branch and optimal recording conditions, we compared the decerebrate state to urethane, urethane-chloralose and pentobarbital-chloralose anaesthesia with regard to level of chronotropic ...
Gerson Myron C - - 2003
BACKGROUND: Patients with a deletion of 4 consecutive amino acids in the gene encoding for the alpha(2C)-adrenergic receptor (alpha(2C)Del322-325) have an increased prevalence of clinical heart failure, worse clinical status, and a lower left ventricular ejection fraction compared with patients without this deletion. We postulated that patients with the alpha(2C)Del322-325 ...
Cohn Jay N - - 2003
The association between sympathetic activation and mortality in chronic heart failure and the favorable effect of beta blocking drugs has raised the possibility of therapeutic efficacy for central sympathetic inhibition with sustained-release (SR) moxonidine, an imidazoline receptor agonist. A randomized double-blind, placebo-controlled trial was initiated in 425 centers in 17 ...
Mangin Laurence - - 2003
Hemodynamic alterations during balloon carotid angioplasty (BCA) and stenting have been ascribed to the consequences of direct carotid baroreceptor stimulation during balloon inflation. BCA with stenting in patients with carotid atheromatous stenoses offers a unique opportunity for elucidating the cardiovascular autonomic response to direct transient intravascular stimulation of the baroreceptors. ...
Arnol Miha - - 2003
Variability in atrioventricular (AV) conduction has been described in healthy subjects, whereas data for coronary patients are lacking. This study was designed to evaluate AV conduction variability in patients with stable coronary artery disease. Beat-to-beat PR interval variability with 5-minute resting high-resolution electrocardiogram recordings was measured in 30 men (mean ...
Toyama Takuji - - 2003
Carvedilol and metoprolol have been reported to be effective in the treatment of patients with chronic heart failure. However, to our knowledge, there have been no studies comparing the effects of the 2 drugs on cardiac function, including cardiac sympathetic nerve activity. We compared 15 patients with dilated cardiomyopathy (DCM) ...
Karayaylali Ibrahim - - 2003
OBJECTIVE: Autonomic neuropathy and impairment of left ventricular functions (LVF) have been frequently encountered in chronic renal failure (CRF). The aim of the present study was to evaluate the relationship of cardiac autonomic modulation impairments, as assessed by means of heart rate variability (HRV), with clinical characteristics, and left ventricular ...
Dworschak Martin - - 2003
Impaired heart rate variability (HRV) has been described postoperatively. Diminished HRV may be related to myocardial ischemia and potentially causes circulatory instability. Cardiac ischemic events and a compromised cardiovascular function are not uncommon after aortic surgery. Circadian variation of HRV seems to be a prognostically more important parameter than HRV ...
Kikuchi Yutaka - - 2003
BACKGROUND: Despite anticoagulant therapy, many patients with Kawasaki disease and giant coronary artery aneurysm develop myocardial infarction. These patients have a high risk of sudden death, but the etiology is not clear. We studied autonomic function and the possibility of malignant ventricular arrhythmia through heart rate variability. METHODS: We studied ...
Arora Rakesh C - - 2003
The purpose of this study was to test the hypothesis that early-stage heart failure differentially affects the intrinsic cardiac nervous system's capacity to regulate cardiac function. After 2 wk of rapid ventricular pacing in nine anesthetized canines, cardiac and right atrial neuronal function were evaluated in situ in response to ...
Chiladakis John A - - 2003
BACKGROUND: The cardiodepressor Bezold-Jarisch reflex (BJR) in acute inferior myocardial infarction (AMI) is traditionally considered as an indicator of successful thrombolysis. HYPOTHESIS: The study aim was to elucidate the role of the autonomic nervous system in the pathogenesis of a BJR response in patients with AMI by tracing spectral profiles ...
Pather N - - 2003
Cardiac sympathetic denervation for intractable angina pectoris in patients unsuitable for conventional revascularization is currently gaining popularity since this procedure may be performed via minimally invasive surgery. A thorough understanding of cardiac innervation and its variations is crucial to successfully effect cardiac denervation. This study aimed to demonstrate the cervical ...
Rossi Lino - - 2003
BACKGROUND: Debate regarding the alterations of the cardiac innervation in an evolving myocardial infarction and transplanted hearts is still raging and most studies are based on radionuclide uptake of neurotransmitters or on the evaluation of the cardiorespiratory reflex. METHODS: The present investigation, upon human autoptic specimens of 57 infarcts and ...
Toweill Daniel L - - 2003
OBJECTIVE: To determine whether heart rate variability metrics provide an accurate method of monitoring depth of anesthesia, assessing the response to painful stimuli, and assessing neuroautonomic regulation of cardiac activity in children receiving propofol anesthesia for short-duration procedures. DESIGN: Prospective, case series. SETTING: Sixteen-bed pediatric intensive care unit, oncology unit, ...
Pyetan Erez - - 2003
When spectral analysis of the heart rate (HR) signal is performed, it is quite common to attribute the HF indexes of heart rate variability (HRV) to cardiac vagal control. The paradigm underlying this attribution states that changes in cardiac vagal outflow correspond to a proportional change in respiratory sinus arrhythmia ...
Parthenakis Fragiskos I - - 2003
Experimental studies have shown that cytokine production by the heart may be regulated by sympathetic nervous system stimulation of cardiac beta-adrenergic receptors. Proinflammatory cytokine levels are increased in heart failure, whereas cardiac fixation of 123-I-metaiodobenzylguanidine (MIBG) has been used to study myocardial adrenergic innervation. This study was designed to assess ...
Sampaio Karla N - - 2003
Vagal cardioinhibition is exerted through a reduction not only in the heart rate but also in the rate of propagation of the cardiac action potential and in myocardial contractility. In several species, such effects can be produced independently by selective activation of ganglia in identified 'fat pads'. In this study ...
Björkman Jan-Arne - - 2003
OBJECTIVE: This study was undertaken to determine whether stimulation of sympathetic cardiac nerves induces release of the thrombolytic enzyme tissue-type plasminogen activator (t-PA) in the coronary vascular bed. METHODS AND RESULTS: Anesthetized pigs were studied in an open chest model. Bilateral vagotomy was performed, and sympathetic cardiac nerves were activated ...
Nakata Tomoaki - - 2003
BACKGROUND: Although altered cardiac sympathetic innervation is related to fatal outcome, the mechanisms and prognostic value of an initial cardiac metaiodobenzylguanidine (MIBG) defect are not known. METHODS AND RESULTS: After quantitative cardiac MIBG imaging, 205 patients with left ventricular ejection fraction <50% were prospectively followed up with a primary end-point ...
Minamihaba Osamu - - 2003
BACKGROUND: It is known that heart rate shows complex behavior, long-term fluctuation of heart rate, and short-term fluctuations in heart failure. Analyzing these properties and examining the relationship to the disease, severity may increase the understanding of the background of heart rate variability (HRV). METHODS: In 61 patients (mean age ...
Arora Rishi - - 2003
BACKGROUND: Iodine 123 metaiodobenzylguanidine (MIBG) imaging and heart rate variability (HRV) analysis were compared in patients with an implantable cardioverter defibrillator (ICD) who did and did not receive defibrillator discharges. Although the ICD has been shown to abort potentially fatal ventricular arrhythmias, identification of patients who most benefit from this ...
Tarkiainen Tuula H - - 2003
Epidemiological studies have shown that air pollution is associated with increased cardiovascular mortality. Although the pathophysiological mechanisms behind this association have remained largely unknown, it has been suggested that changes in cardiac autonomic function may play a role. In this study, we investigated the association between acute carbon monoxide (CO) ...
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