Search Results
Results 451 - 500 of 1268
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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 ...
Laciar E - - 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 ...
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 ...
Verrier Richard L - - 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) ...
Grassi Guido - - 2003
Animal studies have conclusively shown that the sympathetic nervous system plays a major role not only in regulating sinus node activity but also in promoting cardiac rhythm alterations. Less univocal and often circumstantial have been the evidences collected on this issue in humans. However, the introduction of the microneurographic technique ...
Aggarwal Anuradha - - 2003
This study examined the effects of low doses of intravenous clonidine on regional and global sympathetic nervous system activity in heart failure. In heart failure, adrenoceptor-blocking treatments have a limited sphere of activity. Centrally acting sympatholytic therapies should be further investigated, with a specific emphasis on targeting cardiac and renal ...
Kasama Shu - - 2003
OBJECTIVES: We sought to evaluate the effects of spironolactone on cardiac sympathetic nerve activity and left ventricular (LV) remodeling in patients with dilated cardiomyopathy (DCM). BACKGROUND: Aldosterone prevents the uptake of norepinephrine and promotes structural remodeling of the heart. Spironolactone, an aldosterone receptor blocker, improves LV remodeling in patients with ...
Abildstrom Steen Z - - 2003
INTRODUCTION: The aim of this study was to evaluate and compare heart rate and heart rate variability (HRV) in risk prediction after acute myocardial infarction (MI) and to evaluate the effect of beta-blocker treatment on the prognostic performance of heart rate and HRV. METHODS AND RESULTS: Three hundred sixty-six patients ...
Fukuta Hidekatsu - - 2003
BACKGROUND: Although decreased heart rate variability (HRV) is an independent predictor of death in various populations, its prognostic value in patients with end-stage renal disease on chronic haemodialysis is unknown. METHODS: We prospectively studied 120 chronic haemodialysis patients (age 61+/-11 years; males 51%; diabetics 38%; duration of haemodialysis therapy 50+/-114 ...
Liang Chang-seng - - 2003
We reported recently that inhibition of neuronal reuptake of norepinephrine (NE) by desipramine prevented the reduction of sympathetic neurotransmitters in the failing right ventricle of right heart failure animals. In this study, we studied whether desipramine also reduced the sympathetic neurotransmitter loss in animals with left heart failure induced by ...
Yamada Takahisa - - 2003
OBJECTIVES: We sought to prospectively compare the prognostic value of cardiac iodine-123 (I-123) metaiodobenzylguanidine (MIBG) imaging with that of heart rate variability (HRV) in patients with mild-to-moderate chronic heart failure (HF). BACKGROUND: Cardiac I-123 MIBG imaging, which reflects cardiac adrenergic nerve activity, provides prognostic information on chronic HF patients. Reduced ...
Pater Cornel - - 2003
BACKGROUND: A large body of data derived from animal, epidemiological and clinical studies indicate that n-3 polyunsaturated fatty acids have a favourable effect on the prognosis of patients with cardiovascular disease in general, and on reducing sudden death in particular.Depressed heart rate variability (HRV), an indicator of impairment of the ...
Meyer, Michael
The complexity of the cardiac rhythm is demonstrated to exhibit self-affine multifractal variability. The dynamics of heartbeat interval time series was analyzed by application of the multifractal formalism based on the Cramer theory of large deviations. The continuous multifractal large deviation spectrum uncovers the nonlinear fractal properties in the dynamics ...
Jokinen Vesa - - 2003
AIM: This research was designed to study the temporal changes in cardiovascular autonomic regulation, assessed by 24-hour heart rate (HR) variability, and the possible relation of changes in HR variability to cardiovascular risk factors and progression of coronary artery disease (CAD) among type II diabetic subjects. METHOD: In a single-center ...
Ozdemir Ozcan - - 2003
In this prospective study, we set out to determine whether analysis of heart rate variability (HRV) in patients with exercise-induced ventricular tachycardia (EIVT) and normal coronary arteries would reveal increased sympathetic nervous system activity. From January 1996 to December 2001, we compared 16 patients with EIVT and normal coronary arteries ...
Singh Ram B - - 2003
OBJECTIVES: To review mechanisms of circadian variations in heart rate variability (HRV) and blood pressure variability (BPV) and mortality and morbidity due to cardiovascular diseases (CVD). METHODS: Results from 7-day/24-h HRV and BPV are interpreted by gender and age-specified reference values in the context of a Medline search. RESULTS: Abnormal ...
Gang Yi - - 2003
Autonomic nervous system plays an integral role in homeostasis. Autonomic modulation can frequently be altered in patients with cardiac disorders as well as in patients with other critical illnesses or injuries. Assessment of heart rate variability is based on analysis of consecutive normal R-R intervals and may provide quantitative information ...
Zosky Graeme R - - 2003
We investigated the effect of parasympathetic antagonism on the patterns of heart rate during torpor in the western pygmy possum Cercatetus concinnus (Marsupialia: Burramyidae). This is the first study to examine the influence of the autonomic nervous system on cardiac function in a metatherian hibernator. During torpor, antagonism of the ...
Galuszka Jan - - 2002
Heart rate variability evaluation is a useful diagnostic tool for autonomic nervous balance assessment. The role of the autonomic nervous system in aetiology of atrial fibrillation is sometimes clear as a trigger from a patient's history, but mostly it acts as a modulating factor which is not easy to detect. ...
Utell Mark J - - 2002
A recent series of epidemiologic reports have shown associations between fine particulate matter (PM) levels and increased cardiovascular morbidity and mortality. Elevated PM levels have been linked with cardiac events, including serious ventricular arrhythmias and myocardial infarction. A workshop brought together epidemiologists, cardiologists, and toxicologists from academia, government, and industry ...
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