Search Results
Results 501 - 550 of 1297
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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 ...
Sosnowski Maciej - - 2002
THE AIMS OF OUR STUDY WERE: (1) to establish the normal limit of the heart rate variability (HRV) indices in a healthy population and in its four age-related subgroups, including a new HRV index, HRV fraction; and (2) to analyse the frequency and predictive value of abnormally low HRV in ...
Toledo Eran - - 2003
Myocardial infarction (MI) is known to elicit activation of the autonomic nervous system. Reperfusion, induced by thrombolysis, is thus expected to bring about a shift in the balance between the sympathetic and vagal systems, according to the infarct location. In this study, we explored the correlation between reperfusion and the ...
Goldstein David S - - 2002
The term dysautonomia refers to a change in autonomic nervous system function that adversely affects health. The changes range from transient, occasional episodes of neurally mediated hypotension to progressive neurodegenerative diseases; from disorders in which altered autonomic function plays a primary pathophysiologic role to disorders in which it worsens an ...
Gaudino Mario - - 2002
BACKGROUND: This study was conceived to explore the correspondence between scintigraphic imaging of the sympathetic innervation of human postischemic left ventricular aneurysms and direct immunohistochemical localization of the nerve fibers in the same area. MATERIALS AND METHODS: In 7 patients undergoing left ventricular aneurysmectomy for postischemic ventricular aneurysm, the findings ...
Ros Magdalena - - 2002
BACKGROUND: Left ventricular isovolumic relaxation responses to changes in afterload or preload may be mediated, in part, by reflex changes in sympathetic nervous system activity. PATIENTS AND METHODS: The authors examined whether changes in left ventricular isovolumic relaxation during changes in load were associated with changes in cardiac norepinephrine spillover. ...
Boardman A - - 2002
The long-term aims of this study are to find a parameter derived from the ECG that has a high sensitivity and specificity to asphyxia and, once we know or suspect that asphyxia occurred, to estimate how severe it was. We carried out a pilot study in which 24 adult Wistar ...
Gerson Myron C - - 2002
Carvedilol treatment reduces the mortality rate in patients with congestive heart failure. It is not known whether carvedilol treatment is effective in heart failure patients with substantial cardiac sympathetic nerve dysfunction. The goal of this study was to determine the effect of chronic carvedilol treatment in patients with cardiac sympathetic ...
Goldstein David S - - 2002
BACKGROUND: In postural tachycardia syndrome (POTS) and repeated neurocardiogenic presyncope (NCS), orthostatic intolerance occurs without persistent sympathetic neurocirculatory failure. Whether these conditions involve abnormal cardiac sympathetic innervation or function has been unclear. METHODS AND RESULTS: Patients with POTS or NCS underwent measurements of neurochemical indices of cardiac release, reuptake, and ...
Barman Susan M - - 2003
We tested the hypothesis that the cardiac-related rhythm in muscle sympathetic nerve activity (MSNA) of humans reflects entrainment of a central oscillator by pulse-synchronous baroreceptor nerve activity. Partial autospectral analysis was used to mathematically remove the portion of cardiac-related power in MSNA autospectra that was attributable to its linear relationship ...
Rong Peijing - - 2002
It has been demonstrated that an important clinical phenomenon often associated with visceral diseases is the referred pain to somatic structures, especially to the body area of homo-segmental innervation. It is interesting that the somatic foci of cardiac referred pain were often and mainly distributed along the heart meridian (HM), ...
Davos Constantinos H - - 2002
BACKGROUND: Sustained ventricular tachycardia (VT) and sudden cardiac death (SCD) remain devastating late complications after repair of Tetralogy of Fallot (ToF). Although heart rate variability (HRV) and baroreflex sensitivity (BRS) are recognized as independent markers of autonomic activity and strong predictors of SCD in major cardiovascular disease, little is known ...
Zhao Ning - - 2002
This study was carried out to determine whether selective cardiac autonomic denervation performed on neonatal swine would evoke dysrhythmias later in development. Piglets (n = 27; 5-10 days old) underwent unilateral stellate ganglion ablation, or right cardiac vagotomy, or sham surgery. Fifty to sixty days after denervation, acute experiments were ...
Folino Antonio Franco - - 2002
The identification of subjects with arrhythmogenic right ventricular cardiomyopathy (ARVC) at higher risk for sudden death is an unresolved issue. An influence of the autonomic activity on the genesis of ventricular arrhythmias was postulated. Heart rate variability (HRV) analysis provides a useful method to measure autonomic activity, and is a ...
Stein Phyllis K - - 2002
Real world clinical Holter reports are often difficult to interpret from a heart rate variability (HRV) perspective. In many cases HRV software is absent. Step-by-step HRV assessment from clinical Holter reports includes: making sure that there is enough usable data, assessing maximum and minimum heart rates, assessing circadian HRV from ...
Lombardi Federico - - 2002
Time and frequency domain analysis of heart rate variability (HRV) is a non invasive technique capable of providing information on autonomic modulation of the sinus node and of stratifying risk after myocardial infarction and in heart failure. One of the basic assumptions used to explain the negative predictive value of ...
Guzik Przemysław - - 2002
Identification of high-risk cardiac patients is crucial for stratification strategies and prevention of cardiovascular events, including death. Single ventricular premature beat triggers some oscillations in cardiac cycle duration (the shortening followed by the lengthening of the cycle intervals) in healthy subjects and low-risk patients with ischaemic heart disease and/or heart ...
Imamura Yoshihiro - - 2002
OBJECTIVE: To assess the prognostic value of I-123 metaiodobenzylguanidine (MIBG) scintigraphy findings, and establish the most appropriate method for calculating myocardial MIBG activity in patients with left ventricular dysfunction due to cardiomyopathy (CM). METHODS: Predictors of cardiac death related to progressive heart failure (HF) were examined in 150 patients with ...
Wichterle Dan - - 2002
Proper understanding of the mechanisms involved in heart rate turbulence (HRT) may offer an explanation of why it is such a potent postinfarction risk stratifier. This article reviews the physiological background of ventriculophasic sinus arrhythmia-a phenomenon which shares some underlying physiological features with HRT including cardiac autonomic regulation. It is ...
Zosky G R - - 2002
This study investigated the effect of parasympathetic inhibition on the cardio-ventilatory interaction during torpor in the fat-tailed dunnart (Sminthopsis crassicaudata). Studies on the influence of the autonomic nervous system on cardiac function during torpor have focused on deep hibernation in eutherians. S. crassicaudata was used as a representative of the ...
Lameris Thomas W - - 2002
BACKGROUND: Several studies have suggested that epinephrine augments the release of norepinephrine from sympathetic nerve terminals through stimulation of presynaptic receptors, but evidence pertaining to this mechanism in the heart is scarce and conflicting. Using the microdialysis technique in the porcine heart, we investigated whether epinephrine, taken up by and ...
Hongo Minoru - - 2002
BACKGROUND: Although a high incidence of myocardial adrenergic denervation has been reported in patients with familial amyloid polyneuropathy, assessment of cardiac sympathetic nerve function has not been available in patients with AL (primary) amyloidosis. METHODS: To test the hypothesis that myocardial sympathetic nerve innervation might be impaired and variable according ...
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